iens

iens.scm (48746B)

---

 ; Copyright (c) 2023-2024, Natacha Porté
 ;
 ; Permission to use, copy, modify, and distribute this software for any
 ; purpose with or without fee is hereby granted, provided that the above
 ; copyright notice and this permission notice appear in all copies.
 ;
 ; THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 ; WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 ; MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 ; ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 ; WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 ; ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 ; OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 
 (import (chicken condition)
         (chicken file)
         (chicken file posix)
         (chicken io)
         (chicken process)
         (chicken process signal)
         (chicken process-context)
         (chicken sort)
         (chicken string)
         (chicken time)
         (chicken time posix)
         breadline
         breadline-scheme-completion
         lowdown
         sql-de-lite
         srfi-1
         sxml-serializer)
 
 (define (starts-with? maybe-prefix s)
   (substring=? s maybe-prefix 0 0 (string-length maybe-prefix)))
 
 (define (ends-with? maybe-suffix s)
   (let ((ls  (string-length s))
         (lms (string-length maybe-suffix)))
   (and (>= ls lms)
        (substring=? s maybe-suffix (- ls lms)))))
 
 (define (time->rfc-3339 time)
   (let ((time-str (time->string time "%FT%T%z")))
     (assert (= 24 (string-length time-str)))
     (if (equal? "0000" (substring time-str 20))
         (string-append (substring time-str 0 19) "Z")
         (string-append (substring time-str 0 22)
                        ":"
                        (substring time-str 22)))))
 
 (define (rfc-3339-local seconds)
   (time->rfc-3339 (seconds->local-time seconds)))
 (define (rfc-3339-utc seconds)
   (time->rfc-3339 (seconds->utc-time seconds)))
 (define rfc-3339 rfc-3339-local)
 
 (define (terminate-line line)
   (let ((l (string-length line)))
     (if (or (zero? l)
             (eqv? (string-ref line (sub1 l)) #\newline))
         line
         (string-append line "\n"))))
 
 (define cmd-list '())
 
 (define-syntax defcmd
   (syntax-rules ()
     ((defcmd (name . args) str first . rest)
       (begin
         (set! cmd-list (cons (list (symbol->string 'name) str first) cmd-list))
         (define (name . args) . rest)))))
 
 (define vt100-entry-header "\033[34m")
 (define vt100-reset        "\033[0m")
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Command-Line Processing
 
 (define db-filename #f)
 (define arg-replay #f)
 
 (let ((arg-list (command-line-arguments)))
   (when (>= (length arg-list) 2) (set! arg-replay (cadr arg-list)))
   (when (>= (length arg-list) 1) (set! db-filename (car arg-list))))
 
 ;;;;;;;;;;;;;
 ;; Tracing
 
 (define trace-port #f)
 (define display-trace #t)
 
 (define (trace obj)
   (when display-trace
     (write obj)
     (newline))
   (when trace-port
     (write obj trace-port)
     (newline trace-port)))
 
 ;;;;;;;;;;;;;;;;;;;;;;;
 ;; Persistent Storage
 
 (define db-name
   (if db-filename db-filename "iens.sqlite"))
 
 (define db
   (open-database db-name))
 (write-line (conc "Using database " db-name " with SQLite " library-version))
 (exec (sql db "PRAGMA foreign_keys = ON;"))
 
 (define (db-version)
   (query fetch-value (sql db "PRAGMA user_version;")))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Database Creation/Migration
 
 (when (null? (schema db))
   (write-line "Initializing database with schema v2")
   (for-each
     (lambda (s) (exec (sql/transient db s)))
     (list "CREATE TABLE config (key TEXT PRIMARY KEY, val);"
           "CREATE TABLE tag (id INTEGER PRIMARY KEY,
                              name TEXT NOT NULL,
                              auto INTEGER DEFAULT 0);"
           "CREATE TABLE entry (id INTEGER PRIMARY KEY,
              url TEXT NOT NULL, type TEXT, description TEXT, notes TEXT,
              protected INTEGER DEFAULT 0, ptime INTEGER,
              ctime INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP,
              mtime INTEGER NOT NULL DEFAULT CURRENT_TIMESTAMP);"
           "CREATE TABLE tagrel (url_id REFERENCES entry(id)
                                   ON UPDATE CASCADE ON DELETE CASCADE,
                                 tag_id REFERENCES tag(id)
                                   ON UPDATE CASCADE ON DELETE CASCADE);"
           "CREATE TABLE feed (id INTEGER PRIMARY KEY, filename TEXT NOT NULL,
                               url TEXT NOT NULL, selector TEXT NOT NULL,
                               title TEXT NOT NULL,
                               active INTEGER NOT NULL DEFAULT 1,
                               mtime INTEGER);"
           "CREATE TABLE selector (id INTEGER PRIMARY KEY, text TEXT);"
           "CREATE INDEX i_mtime ON entry(mtime);"
           "CREATE INDEX i_pmtime ON entry(protected,mtime);"
           "CREATE UNIQUE INDEX i_url ON entry(url);"
           "CREATE UNIQUE INDEX i_tag ON tag(name);"
           "CREATE UNIQUE INDEX i_rel0 ON tagrel(url_id,tag_id);"
           "CREATE INDEX i_rel1 ON tagrel(url_id);"
           "CREATE INDEX i_rel2 ON tagrel(tag_id);"
           "PRAGMA user_version = 2;")))
 
 (when (= 0 (db-version))
   (write-line "Updating database schema from v0 to v1")
   (assert (= 1 (query fetch-value
                       (sql db "SELECT val FROM config WHERE key = ?;")
                       "schema-version")))
   (for-each
     (lambda (s) (exec (sql/transient db s)))
     (list "CREATE TABLE IF NOT EXISTS
              selector (id INTEGER PRIMARY KEY, text TEXT);"
           "DELETE FROM config WHERE key='schema-version';"
           "PRAGMA user_version = 1;")))
 
 (when (= 1 (db-version))
   (write-line "Updating database schema from v1 to v2")
   (for-each
     (lambda (s) (exec (sql/transient db s)))
     (list "ALTER TABLE feed ADD COLUMN mtime INTEGER;"
           "PRAGMA user_version = 2;")))
 
 (assert (= 2 (db-version)))
 
 ;;;;;;;;;;;;;;;;;;
 ;; Configuration
 
 (define config-author-name #f)
 (define config-author-email #f)
 (define config-author-uri #f)
 (define config-autogenerate #f)
 (define config-editor #f)
 (define config-entry-id-prefix "")
 (define config-list-tagged-count 0)
 (define config-verbose #f)
 
 (define default-editor
   (let ((term   (get-environment-variable "TERM"))
         (visual (get-environment-variable "VISUAL"))
         (editor (get-environment-variable "EDITOR"))
         (fallback "vi"))
     (cond
       ((and visual term (not (equal? "dumb" term))) visual)
       (editor editor)
       (else fallback))))
 
 (define (get-config key)
   (query fetch-value (sql db "SELECT val FROM config WHERE key = ?;") key))
 
 (define (get-config/default key default-value)
   (let ((result (get-config key)))
     (if result
         result
         default-value)))
 
 (define (string->filename data)
   (cond ((not data) #f)
         ((starts-with? "~/" data)
           (string-append (get-environment-variable "HOME")
                          (substring data 1)))
         (else data)))
 
 (define (read-config!)
   (set! display-trace  (not (zero? (get-config/default "display-trace" 0))))
   (set! config-verbose (not (zero? (get-config/default "verbose" 0))))
   (set! rfc-3339        (if (zero? (get-config/default "local-time" 1))
                             rfc-3339-utc rfc-3339-local))
   (set! config-author-name  (get-config "author-name"))
   (set! config-author-email (get-config "author-email"))
   (set! config-author-uri   (get-config "author-uri"))
   (set! config-autogenerate (not (zero? (get-config/default "autogenerate" 0))))
   (set! config-editor       (get-config/default "editor" default-editor))
   (set! config-entry-id-prefix (get-config/default "entry-id-prefix" ""))
   (set! config-list-tagged-count (get-config/default "list-tagged-count" 0))
   (let ((trace-filename (get-config "trace")))
     (when trace-port (close-output-port trace-port))
     (set! trace-port
       (if trace-filename
           (open-output-file (string->filename trace-filename) #:text #:append)
           #f)))
   (history-file (string->filename (get-config "histfile"))))
 
 (read-config!)
 
 (defcmd (print-config . args)
   "[key ...]" "Print configuration"
   (if (null? args)
       (query
         (for-each-row*
           (lambda (key val) (write-line (conc key ": " val))))
         (sql db "SELECT key,val FROM config ORDER BY key;"))
       (let loop ((todo args))
         (unless (null? todo)
           (write-line (conc (car todo) ": " (get-config (car todo))))
           (loop (cdr todo))))))
 
 (defcmd (set-config key val)
   "key value" "Set configuration variable"
   (trace `(set-config ,key ,val))
   (exec (sql db "INSERT OR REPLACE INTO config VALUES (?,?);") key val)
   (read-config!))
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Configurable Query Selectors
 
 (defcmd (add-selector text)
   "\"WHERE …\"" "Creates a pre-defined query selector"
   (trace `(add-select ,text))
   (exec (sql db "INSERT INTO selector(text) VALUES (?);") text)
   (write-line (conc " -> " (last-insert-rowid db))))
 
 (define (call-with-selector arg proc)
   (cond ((string? arg) (proc arg #f))
         ((number? arg) (let ((selector (get-selector arg)))
                          (if selector
                              (proc selector arg)
                              (write-line
                                (conc "No selector #" arg " found")))))
         (else (write-line (conc "Invalid selection argument " arg)))))
 
 (define (get-selector id)
   (query fetch-value (sql db "SELECT text FROM selector WHERE id=?;") id))
 
 (defcmd (list-selectors)
   "" "List pre-defined query selectors"
   (query
     (for-each-row
       (lambda (row)
         (write-line (conc "#" (car row) ": \"" (cadr row) "\""))))
     (sql db "SELECT id,text FROM selector;")))
 
 (defcmd (set-selector id text)
   "id \"WHERE …\"" "Sets a pre-defined query selector"
   (trace `(set-selector ,id ,text))
   (exec (sql db "INSERT OR REPLACE INTO selector(id,text) VALUES (?,?);")
         id text))
 
 ;;;;;;;;;;;;;;;;;;;;;
 ;; Database Updates
 
 ;; Feed Management
 
 (define (set-feed-active id n)
   (exec (sql db "UPDATE feed SET active=? WHERE id=?;") n id))
 
 (defcmd (activate-feed feed-id)
   "feed-id" "Activate the given feed"
   (trace `(activate-feed ,feed-id))
   (set-feed-active feed-id 1))
 
 (defcmd (add-feed filename url selector title)
   "filename url selector title" "Add a new feed"
   (trace `(add-feed ,filename ,url ,selector ,title))
   (exec (sql db
              "INSERT INTO feed(filename,url,selector,title) VALUES (?,?,?,?);")
         filename url selector title)
   (write-line (conc "Added feed " (last-insert-rowid db))))
 
 (defcmd (disable-feed feed-id)
   "feed-id" "Disable the given feed"
   (trace `(disable-feed ,feed-id))
   (set-feed-active feed-id 0))
 
 (defcmd (list-feeds)
   "" "Display all feeds"
   (query
     (map-rows*
       (lambda (id filename url selector title active-int mtime)
         (write-line (conc (if (zero? active-int)
                               (conc "(" id ")")
                               (conc "#" id))
                           " "
                           filename
                           " - "
                           title))
         (write-line (conc "    " url))
         (write-line (conc "    " selector))
         (unless (null? mtime)
           (write-line (conc "    Updated " (rfc-3339 mtime))))))
     (sql db "SELECT id,filename,url,selector,title,active,mtime FROM feed;")))
 
 (defcmd (remove-feed feed-id)
   "feed-id" "Remove the given feed"
   (trace `(remove-feed ,feed-id))
   (exec (sql db "DELETE FROM feed WHERE id=?;") feed-id))
 
 (define (touch-feed mtime feed-id)
   (trace `(touch-feed ,mtime ,feed-id))
   (exec (sql db "UPDATE feed SET mtime=? WHERE id=?;") mtime feed-id))
 
 ;; Feed Caching
 
 (define (build-signature selector)
   (query fetch-rows
          (sql db (string-append "SELECT id,mtime FROM entry " selector ";"))))
 
 (define (car< a b) (< (car a) (car b)))
 
 (define (diff-signature old-sig new-sig)
   (let loop ((old    (sort old-sig car<))
              (new    (sort new-sig car<))
              (result '()))
     (cond ((and (null? old) (null? new))
               result)
           ((null? old)
               (loop old
                     (cdr new)
                     (cons `(add ,@(car new)) result)))
           ((null? new)
               (loop (cdr old)
                     new
                     (cons `(del ,@(car old)) result)))
           ((equal? (car new) (car old))
               (loop (cdr old)
                     (cdr new)
                     result))
           ((= (caar new) (caar old))
               (loop (cdr old)
                     (cdr new)
                     (cons `(chg ,@(car old) ,(cadar new)) result)))
           ((< (caar new) (caar old))
               (loop old
                     (cdr new)
                     (cons `(add ,@(car new)) result)))
           ((> (caar new) (caar old))
               (loop (cdr old)
                     new
                     (cons `(del ,@(car old)) result)))
           (else (assert #f "Should be unreachable")))))
 
 (define (write-diff sig-diff)
   (for-each
     (lambda (hunk)
       (cond ((eqv? (car hunk) 'add)
               (write-line (conc "    added item #" (cadr hunk)
                                 " at " (rfc-3339 (caddr hunk)))))
             ((eqv? (car hunk) 'del)
               (write-line (conc "    removed item #" (cadr hunk)
                                 " at " (rfc-3339 (caddr hunk)))))
             ((eqv? (car hunk) 'chg)
               (write-line (conc "    updated item #" (cadr hunk)
                                 ": " (rfc-3339 (caddr hunk))
                                 " → " (rfc-3339 (cadddr hunk)))))
           (else (assert #f "Should be unreachable"))))
     sig-diff))
 
 (define feed-cache
   (query (map-rows* (lambda (id selector)
                             (cons id (build-signature selector))))
          (sql db "SELECT id,selector FROM feed WHERE active=1;")))
 (define dirty-feeds '())
 
 (define (check-feed* id)
   (let ((new (query fetch-value
                     (sql db "SELECT selector FROM feed WHERE id=?;")
                     id))
         (old (alist-ref id feed-cache = '())))
     (cond ((and (not new) (null? old))
             (write-line (conc "Feed #" id " does not exist")))
           ((not new)
             (write-line (conc "Feed #" id " does not exist anymore")))
           ((null? old)
             (write-line (conc "Feed #" id " is not cached")))
           (else
             (let ((sig-diff (diff-signature old (build-signature new))))
               (if (null? sig-diff)
                   (write-line (conc "Feed #" id " has not changed"))
                   (write-line (conc "Feed #" id " was modified:")))
               (write-diff sig-diff))))))
 
 (defcmd (check-feed . args)
   "[feed-id ...]" "Check the cache for the given feeds, or all active feeds"
   (for-each check-feed*
     (if (null? args)
         (query fetch-column (sql db "SELECT id FROM feed WHERE active=1;"))
         args)))
 
 (define (update-feed-cache* mtime id)
   (let ((data (query fetch-row
                      (sql db "SELECT mtime,selector,filename,title,url
                               FROM feed WHERE id=?;")
                      id))
         (old-sig (alist-ref id feed-cache = '())))
     (if (null? data)
         (write-line (conc "Feed #" id " does not exist"))
         (let ((new-sig (build-signature (cadr data))))
           (unless (equal? old-sig new-sig)
             (when (or (null? (car data))
                       (> mtime (car data)))
               (touch-feed mtime id)
               (set! (car data) mtime))
             (when config-verbose
                (write-line (if config-autogenerate
                                (conc "Autogenerating feed " id)
                                (conc "Marking feed " id " as dirty:")))
                (write-diff (diff-signature old-sig new-sig)))
             (if config-autogenerate
                 (with-output-to-file (caddr data) ;filename
                   (cut write-feed
                     (car data) ;mtime
                     (list-ref data 3) ;title
                     (list-ref data 4) ;url
                     (query fetch-rows
                       (sql db (string-append "SELECT id,url,type,description,
                                                      notes,ptime,ctime,mtime
                                               FROM entry " (cadr data) ";")))))
                 (unless (any (cut = id <>) dirty-feeds)
                   (set! dirty-feeds (cons id dirty-feeds))))
             (set! feed-cache
                   (alist-update! id new-sig feed-cache =)))))))
 
 (define (update-feed-cache mtime . id-list)
   (for-each
     (cut update-feed-cache* mtime <>)
     (if (null? id-list)
         (query fetch-column (sql db "SELECT id FROM feed WHERE active=1;"))
         id-list)))
 
 ;; Tag Management
 
 (define (set-tag-auto name auto)
   (exec (sql db "UPDATE tag SET auto=? WHERE name=?;") auto name))
 
 (defcmd (add-auto-tag name . rest)
   "tag-name [tag-name ...]" "Set tags as automatic"
   (trace `(add-auto-tag ,name))
   (set-tag-auto name 1)
   (unless (null? rest)
     (apply add-auto-tag rest)))
 
 (defcmd (add-tag name . rest)
   "tag-name [tag-name ...]" "Create a new tag"
   (trace `(add-tag ,name))
   (exec (sql db "INSERT INTO tag(name) VALUES (?);") name)
   (unless (null? rest)
     (apply add-tag rest)))
 
 (defcmd (auto-tags . tag-list)
   "[tag-name ...]" "Set the list of automatic tags"
   (trace `(auto-tags . ,tag-list))
   (with-transaction db
     (lambda ()
       (exec (sql db "UPDATE tag SET auto=0;"))
       (let loop ((todo tag-list))
         (unless (null? todo)
           (set-tag-auto (car todo) 1)
           (loop (cdr todo)))))))
 
 (define (n-split l n)
   (let loop ((todo-l l) (todo-n n) (acc '()))
     (if (or (zero? todo-n) (null? todo-l))
         (reverse acc)
         (let ((chunk-size (ceiling (/ (length todo-l) todo-n))))
           (loop (drop todo-l chunk-size)
                 (sub1 todo-n)
                 (cons (take todo-l chunk-size) acc))))))
 
 (define (expand-cols cols)
   (let loop ((todo cols) (acc '()))
     (if (> (length todo) 1)
         (loop
           (cons (append (cadr todo)
                         (make-list (- (length (car todo)) (length (cadr todo)))
                                    ""))
                 (cddr todo))
           (let ((width (apply max (map string-length (car todo)))))
             (cons
               (append
                 (map (lambda (s t)
                        (string-append
                          s
                          (make-string (- width -2 (string-length s))
                                       #\space)))
                      (car todo)
                      (cadr todo))
                 (drop (car todo) (length (cadr todo))))
               acc)))
         (reverse (append todo acc)))))
 
 (defcmd (list-tags #!optional (cols 1) (threshold 0))
   "[n-columns [min-count]]"
   "List available tag, automatic tags are marked with *"
   (apply for-each
          (lambda row
            (write-line (apply string-append row)))
          (expand-cols
            (n-split
              (query
                (map-rows*
                  (lambda (name auto count)
                    (conc name (if (zero? auto) " (" "* (") count ")")))
                (sql db "SELECT name,auto,COUNT(tagrel.url_id) AS cnt
                         FROM tag OUTER LEFT JOIN tagrel ON id=tagrel.tag_id
                         GROUP BY id HAVING cnt >= ? ORDER BY name;")
                threshold)
              cols))))
 
 (defcmd (remove-auto-tag name . rest)
   "[tag-name ...]" "Set tags as not automatic"
   (trace `(remove-auto-tag ,name))
   (set-tag-auto name 0)
   (unless (null? rest)
     (apply remove-auto-tag rest)))
 
 (defcmd (remove-tag name . rest)
   "tag-name [tag-name ...]" "Remove tags"
   (trace `(remove-tag ,name))
   (exec (sql db "DELETE FROM tag WHERE name=?;") name)
   (unless (null? rest)
     (apply remove-tag rest)))
 
 (defcmd (rename-tag old-name new-name)
   "old-tag-name new-tag-name" "Rename a tag, preserving associations"
   (trace `(rename-tag ,old-name ,new-name))
   (exec (sql db "UPDATE tag SET name=? WHERE name=?;") new-name old-name))
 
 ;; Entry Protection
 
 (define (is-protected? entry-id)
   (not (zero?
           (query fetch-value
                  (sql db "SELECT protected FROM entry WHERE id=?;")
                  entry-id))))
 
 (define protection-overrides '())
 
 (define (is-overridden? entry-id)
   (any (cut = entry-id <>) protection-overrides))
 
 (define (update-allowed? entry-id)
   (or (not (is-protected? entry-id)) (is-overridden? entry-id)))
 
 (define-syntax unless-protected
   (syntax-rules ()
     ((unless-protected entry-id . form)
       (if (update-allowed? entry-id)
           (begin . form)
           (write-line (conc "Warning: entry " entry-id " is protected"))))))
 
 (define (unoverride! entry-id)
   (trace `(unoverride! ,entry-id))
   (set! protection-overrides (delete! entry-id protection-overrides =)))
 
 (define (protect* ptime entry-id)
   (trace `(protect ,ptime ,entry-id))
   (unless-protected entry-id
      (exec (sql db "UPDATE entry SET protected=1,ptime=? WHERE id=?;")
            ptime entry-id)
      (update-feed-cache ptime)))
 
 (defcmd (protect . args)
   "[[timestamp] entry-id]" "Protect entries from modification"
   (cond ((null? args)
           (protect* (current-seconds) cur-entry))
         ((null? (cdr args))
           (protect* (current-seconds) (car args)))
         (else
           (protect* (car args) (cadr args)))))
 
 (define (override! entry-id)
   (trace `(override! ,entry-id))
   (unless (update-allowed? entry-id)
     (set! protection-overrides (cons entry-id protection-overrides))))
 
 (define (unprotect* mtime entry-id)
   (trace `(unprotect ,mtime ,entry-id))
   (exec (sql db "UPDATE entry SET protected=0,ptime=NULL,mtime=? WHERE id=?;")
         mtime entry-id)
   (update-feed-cache mtime))
 
 (defcmd (unprotect . args)
   "[[timestamp] entry-id]" "Unprotect entries from modification"
   (cond ((null? args)
           (unprotect* (current-seconds) cur-entry))
         ((null? (cdr args))
           (unprotect* (current-seconds) (car args)))
         (else
           (unprotect* (car args) (cadr args)))))
 
 (define (without-protection* entry-id proc)
   (if (or (procedure? proc) (list? proc))
       (let ((prev-cur-entry-id cur-entry))
         (set! cur-entry entry-id)
         (if (is-protected? entry-id)
             (begin
               (override! entry-id)
               (if (procedure? proc) (proc) (eval proc))
               (unoverride! entry-id))
             (if (procedure? proc) (proc) (eval proc)))
         (set! cur-entry prev-cur-entry-id))
       (write-line (conc "Invalid procedure " proc))))
 
 (defcmd (without-protection! first . args)
   "[entry-id] '(...)" "Perform updates bypassing protection"
   (cond ((null? args)
           (without-protection* cur-entry first))
         ((and (null? (cdr args)) (integer? first))
           (without-protection* first (car args)))
         (else (assert #f "Invalid arguments " (cons first args)))))
 
 ;; Entry Management
 
 (define cur-entry
   (query fetch-value
          (sql/transient db "SELECT id FROM entry ORDER BY id DESC LIMIT 1;")))
 
 (define (time-id-strings args)
   (cond ((or (null? args) (string? (car args)))
           (list (current-seconds) cur-entry args))
         ((not (integer? (car args)))
           (assert #f "Unknown type parameter for " (car args)))
         ((or (null? (cdr args)) (string? (cadr args)))
           (list (current-seconds) (car args) (cdr args)))
         ((integer? (cadr args))
           (list (car args) (cadr args) (cddr args)))
         (else (assert #f "Unknown type parameter for " (cadr args)))))
 
 (define (add-entry* ctime url notes)
   (trace `(add-entry ,ctime ,url ,notes))
   (let ((new-id
     (with-transaction db
       (lambda ()
         (exec (sql db "INSERT INTO entry(url,notes,ctime,mtime) VALUES (?,?,?,?);")
               url notes ctime ctime)
         (let ((new-id (last-insert-rowid db)))
           (exec (sql db "INSERT INTO tagrel SELECT ?,id FROM tag WHERE auto=1;")
                 new-id)
           new-id)))))
     (set! cur-entry new-id)
     (write-line (conc "Added " new-id)))
   (update-feed-cache ctime))
 
 (defcmd (add-entry first second . rest)
   "[timestamp] URL note-line [note-line ...]" "Create a new entry"
   (if (or (null? rest) (string? first))
       (add-entry* (current-seconds)
                   first
                   (apply string-append (map terminate-line (cons second rest))))
       (add-entry* first
                   second
                   (apply string-append (map terminate-line rest)))))
 
 (define (add-notes* mtime entry-id lines)
   (unless (null? lines)
     (trace `(add-notes ,mtime ,entry-id . ,lines))
     (with-transaction db
       (lambda ()
         (let ((prev-notes (query fetch-value
                                  (sql db "SELECT notes FROM entry WHERE id=?;")
                                  entry-id)))
           (unless-protected entry-id
             (exec (sql db "UPDATE entry SET notes=?,mtime=? WHERE id=?;")
                   (apply string-append prev-notes
                     (map terminate-line lines))
                   mtime
                   entry-id))))))
   (update-feed-cache mtime))
 
 (defcmd (add-notes . args)
   "[[timestamp] entry-id] note-line [note-line ...]"
   "Append new lines of notes"
   (apply add-notes* (time-id-strings args)))
 
 (define (print-entry-row id url type descr notes protected ptime ctime mtime tags)
   (write-line (conc vt100-entry-header
                     "#" id (if (zero? protected) "" "*") " - " url
                     vt100-reset))
     (unless (null? ctime) (write-line (conc "Created   " (rfc-3339 ctime))))
     (unless (null? ptime) (write-line (conc "Protected " (rfc-3339 ptime))))
     (unless (null? mtime) (write-line (conc "Modified  " (rfc-3339 mtime))))
     (unless (null? descr)
       (if (null? type)
           (write-line "Descripiton:")
           (write-line (conc "Description (" type "):")))
       (write-string descr))
     (unless (null? notes)
       (write-line (conc "Notes:"))
       (write-string notes))
     (if (null? tags)
         (write-line "No tags.")
         (write-line (string-append "Tags: " tags))))
 
 (define (print-listed-entry-row id url notes protected)
   (write-line (conc vt100-entry-header
                     "#" id (if (zero? protected) "" "*") " - " url
                     vt100-reset))
   (write-string notes))
 
 (define (count-selection* text id)
   (write-line (string-append (if id (conc "#" id ": ") "")
                              "\"" text "\""))
   (write-line (conc " -> " (query fetch-value
                                   ((if id sql sql/transient)
                                     db
                                     (string-append
                                       "SELECT COUNT(id) FROM entry "
                                       text ";"))))))
 
 (defcmd (count-selection . args)
   "\"WHERE ...\"|selector-id ..." "Count results of a custom queries"
   (if (null? args)
       (query (for-each-row* count-selection*)
              (sql db "SELECT text,id FROM selector;"))
       (let loop ((todo args))
         (unless (null? todo)
           (call-with-selector (car todo) count-selection*)
           (loop (cdr todo))))))
 
 (defcmd (list-selection arg)
   "\"WHERE ...\"|selector-id" "Display a custom query as an entry list"
   (call-with-selector arg
     (lambda (selector id)
       (query (for-each-row* print-listed-entry-row)
              ((if id sql sql/transient) db
                (string-append "SELECT id,url,notes,protected FROM entry "
                               selector ";"))))))
 
 (defcmd (list-tagged tag-name #!optional (count config-list-tagged-count))
   "tag-name [limit]" "Display entries with the given tag"
   (query (for-each-row* print-listed-entry-row)
          (sql db (cond ((positive? count)
                          "SELECT * FROM
                             (SELECT id,url,notes,protected FROM entry
                               WHERE id IN (SELECT url_id FROM tagrel
                                             WHERE tag_id IN (SELECT id FROM tag
                                                               WHERE name=?))
                             ORDER BY id DESC LIMIT ?)
                            ORDER BY id ASC;")
                        ((negative? count)
                          "SELECT id,url,notes,protected FROM entry
                             WHERE id IN (SELECT url_id FROM tagrel
                                           WHERE tag_id IN (SELECT id FROM tag
                                                             WHERE name=?))
                           ORDER BY id ASC LIMIT ?;")
                        (else ; (zero? count)
                          "SELECT id,url,notes,protected FROM entry
                             WHERE id IN (SELECT url_id FROM tagrel
                                           WHERE tag_id IN (SELECT id FROM tag
                                                             WHERE name=?))
                               OR id=?
                           ORDER BY id ASC;")))
          tag-name
          (abs count)))
 
 (defcmd (list-untagged)
   "" "Display entries without any tag"
   (query (for-each-row* print-listed-entry-row)
          (sql db "SELECT id,url,notes,protected FROM entry
                    WHERE id NOT IN (SELECT url_id FROM tagrel);")))
 
 (define (print-entry* entry-id)
   (query (for-each-row* print-entry-row)
          (sql db "SELECT entry.id,url,type,description,notes,
                          protected,ptime,ctime,mtime,group_concat(tag.name,' ')
                   FROM entry
                   LEFT OUTER JOIN tagrel ON entry.id=tagrel.url_id
                   LEFT OUTER JOIN tag ON tag.id=tagrel.tag_id
                   WHERE entry.id=? GROUP BY entry.id;")
          entry-id))
 
 (defcmd (print-entry . args)
   "[entry-id]" "Display an entry"
   (if (null? args)
       (print-entry* cur-entry)
       (let loop ((todo args))
         (unless (null? todo)
           (print-entry* (car todo))
           (loop (cdr todo))))))
 
 (defcmd (print-selection arg)
   "\"WHERE ...\"|selector-id" "Display entries from a custom query"
   (call-with-selector arg
     (lambda (selector id)
       (query
         (for-each-row* print-entry-row)
         ((if id sql sql/transient) db
           (string-append
             "SELECT entry.id,url,type,description,notes,
                     protected,ptime,ctime,mtime,group_concat(tag.name,' ')
              FROM entry
              LEFT OUTER JOIN tagrel ON entry.id=tagrel.url_id
              LEFT OUTER JOIN tag ON tag.id=tagrel.tag_id "
             selector
             " GROUP BY entry.id;"))))))
 
 (defcmd (random-tagged tag-name)
   "tag" "Select a random entry with the given tag"
   (let ((entry-id (query fetch-value
                          (sql db "SELECT url_id FROM tagrel WHERE tag_id IN
                                     (SELECT id FROM tag WHERE name=?)
                                   ORDER BY RANDOM() LIMIT 1;")
                          tag-name)))
     (if entry-id
         (begin
           (set! cur-entry entry-id)
           (print-entry))
         (write-line "No such entry found"))))
 
 (defcmd (random-untagged)
   "" "Select a random entry without tag"
   (let ((entry-id (query fetch-value
                          (sql db "SELECT id FROM entry WHERE id NOT IN
                                     (SELECT url_id FROM tagrel)
                                   ORDER BY RANDOM() LIMIT 1;"))))
     (if entry-id
         (begin
           (set! cur-entry entry-id)
           (print-entry))
         (write-line "No such entry found"))))
 
 (define (guess-type str)
   (cond ((null? str) '())
         ((starts-with? "<" str) "html")
         ((or (starts-with? " - " str)
              (starts-with? " + " str)) "markdown-li")
         (else "text")))
 
 (define (set-descr* mtime entry-id type text)
   (trace `(set-descr ,mtime ,entry-id ,type ,text))
   (unless-protected entry-id
     (exec (sql db "UPDATE entry SET type=?,description=?,mtime=? WHERE id=?;")
           type text mtime entry-id)
     (update-feed-cache mtime)))
 
 (defcmd (set-descr first . args)
   "[[[mtime] entry-id] type] description" "Sets an entry description"
   (case (length args)
     ((0) (set-descr* (current-seconds) cur-entry (guess-type first) first))
     ((1) (set-descr* (current-seconds) cur-entry first (car args)))
     ((2) (set-descr* (current-seconds) first (car args) (cadr args)))
     ((3) (set-descr* first (car args) (cadr args) (caddr args)))
     (else (assert #f "Too many arguments to set-descr " (cons first args)))))
 
 (defcmd (set-entry arg)
   "entry-id|url" "Set current entry"
   (cond ((integer? arg)
           (set! cur-entry arg)
           (when config-verbose (print-entry)))
         ((string? arg)
           (let ((id (query fetch-value
                            (sql db "SELECT id FROM entry WHERE url=?;")
                            arg)))
             (if id
                 (begin
                   (set! cur-entry id)
                   (when config-verbose (print-entry)))
                 (write-line (conc "No entry found for \"" arg "\"")))))
         (else (assert #f "Unsupported argument type for " arg))))
 
 (define (touch* mtime entry-id)
   (trace `(touch ,mtime ,entry-id))
   (unless-protected entry-id
     (exec (sql db "UPDATE entry SET mtime=? WHERE id=?;") mtime entry-id)
     (update-feed-cache mtime)))
 
 (define (touch . args)
   (cond ((null? args)
           (touch* (current-seconds) cur-entry))
         ((not (integer? (car args)))
           (assert #f "Bad type for " (car args)))
         ((null? (cdr args))
           (touch* (current-seconds) (car args)))
         ((not (integer? (cadr args)))
           (assert #f "Bad type for " (car args)))
         (else
           (touch* (car args) (cadr args)))))
 
 (define (without-mtime* entry-id proc)
   (if (or (procedure? proc) (list? proc))
       (let ((prev-entry cur-entry)
             (prev-mtime (query fetch-value
                                (sql db "SELECT mtime FROM entry WHERE id=?;")
                                entry-id)))
         (set! cur-entry entry-id)
         (if (procedure? proc) (proc) (eval proc))
         (touch* prev-mtime entry-id)
         (set! cur-entry prev-entry))
       (write-line (conc "Invalid procedure " proc))))
 
 (defcmd (without-mtime! first . args)
   "[entry-id] '(...)" "Perform updates and restore entry mtime"
   (cond ((null? args)
           (without-mtime* cur-entry first))
         ((and (null? (cdr args)) (integer? first))
           (without-mtime* first (car args)))
         (else (assert #f "Invalid arguments " (cons first args)))))
 
 ;; Entry Tagging
 
 (define (print-tags* entry-id)
   (write-line (apply conc (append (list "Tags for " entry-id ":")
     (query (map-rows (lambda (x) (string-append " " (car x))))
            (sql db "SELECT tag.name FROM tagrel
                     OUTER LEFT JOIN tag ON tagrel.tag_id=tag.id
                     WHERE url_id=? ORDER BY tag.name;")
            entry-id)))))
 
 (defcmd (print-tags . args)
   "[entry-id ...]" "Print tags associated with an entry"
   (if (null? args)
       (print-tags* cur-entry)
       (let loop ((todo args))
         (unless (null? todo)
           (print-tags* (car todo))
           (loop (cdr todo))))))
 
 (define (exec-on-tags stmt mtime entry-id tag-list)
   (with-transaction db
     (lambda ()
       (unless-protected entry-id
         (let loop ((todo tag-list))
           (if (null? todo)
               (exec (sql db "UPDATE entry SET mtime=? WHERE id=?;")
                     mtime entry-id)
               (let ((tag-id (query fetch-value
                                    (sql db "SELECT id FROM tag WHERE name=?;")
                                    (car todo))))
                 (if tag-id
                     (exec stmt entry-id tag-id)
                     (write-line (conc "Unknown tag " (car todo))))
                 (loop (cdr todo))))))))
   (print-tags entry-id)
   (update-feed-cache mtime))
 
 (define (retag* mtime entry-id tag-list)
   (trace `(retag ,mtime ,entry-id . ,tag-list))
   (unless-protected entry-id
     (exec (sql db "DELETE FROM tagrel WHERE url_id=?;") entry-id)
     (exec-on-tags (sql db "INSERT OR IGNORE INTO tagrel VALUES (?,?);")
                   mtime entry-id tag-list)))
 
 (defcmd (retag . args)
   "[[timestamp] entry-id] tag-name [tag-name ...]"
   "Overwrite tag list for an entry"
   (apply retag* (time-id-strings args)))
 
 (define (tag* mtime entry-id tag-list)
   (unless (null? tag-list)
     (trace `(tag ,mtime ,entry-id . ,tag-list))
     (exec-on-tags (sql db "INSERT OR IGNORE INTO tagrel VALUES (?,?);")
                   mtime entry-id tag-list)))
 
 (defcmd (tag . args)
   "[[timestamp] entry-id] tag-name [tag-name ...]"
   "Associate tags to an entry"
   (apply tag* (time-id-strings args)))
 
 (define (untag* mtime entry-id tag-list)
   (unless (null? tag-list)
     (trace `(untag ,mtime ,entry-id . ,tag-list))
     (exec-on-tags (sql db "DELETE FROM tagrel WHERE url_id=? AND tag_id=?;")
                   mtime entry-id tag-list)))
 
 (defcmd (untag . args)
   "[[timestamp] entry-id] tag-name [tag-name ...]"
   "Disssociates tags from an entry"
   (apply untag* (time-id-strings args)))
 
 ;;;;;;;;;;;;;;;;;;;;
 ;; Editor Spawning
 
 (define (edit-descr* entry-id)
   (let ((file-name (create-temporary-file
                      (string-append "."
                        (get-config/default "description-ext" "txt"))))
         (fields
            (query fetch-row
                   (sql db "SELECT description,notes FROM entry WHERE id=?;")
                   entry-id)))
     (when fields
       (call-with-output-file file-name
         (lambda (port)
           (unless (null? (car fields))
             (write-string (car fields) #f port))
           (unless (null? (cadr fields))
             (write-string "-+-+-\n" #f port)
             (write-string (cadr fields) #f port)))))
     (when config-editor
       (process-wait
         (process-run (string-append config-editor " " (qs file-name)))))
     (let ((result (call-with-input-file file-name
                     (lambda (port)
                       (let* ((text (read-string #f port))
                              (end  (substring-index-ci "-+-+-\n" text)))
                         (if end
                             (substring text 0 end)
                             text))))))
       (delete-file file-name)
       (if (or (zero? (string-length result))
               (equal? (if (or (null? fields) (null? (car fields)))
                           "" (car fields))
                       result))
           #f
           result))))
 
 
 (defcmd (edit-descr . args)
   "[[mtime] entry-id]" "Describe using an external editor"
   (let ((new-value (case (length args)
                      ((0) (edit-descr* cur-entry))
                      ((1) (edit-descr* (car args)))
                      ((2) (edit-descr* (cadr args)))
                      (else
                        (assert #f "Too many arguments to edit-descr " args)))))
     (when new-value
       (case (length args)
         ((0) (set-descr* (current-seconds)
                          cur-entry
                          (guess-type new-value)
                          new-value))
         ((1) (set-descr* (current-seconds)
                          (car args)
                          (guess-type new-value)
                          new-value))
         ((2) (set-descr* (car args)
                          (cadr args)
                          (guess-type new-value)
                          new-value))
         (else (assert #f "Too many arguments to edit-descr " args))))))
 
 ;;;;;;;;;;;;;;;;;;;;
 ;; Feed Generation
 
 (define (atom-content type descr notes)
   (cond ((null? descr) `(atom:content ,notes))
         ((null? type)  `(atom:content ,descr))
         ((equal? type "markdown-li")
           (let ((acc (open-output-string))
                 (prev-output (current-output-port)))
             (current-output-port acc)
             (let ((result (markdown->html (substring descr 3))))
               (current-output-port prev-output)
               (if result
                   `(atom:content (@ (type "html")) ,(get-output-string acc))
                   `(atom:content ,descr)))))
         (else `(atom:content (@ (type ,type)) ,descr))))
 
 (define (feed->sxml id url type descr notes ptime ctime mtime)
   `(atom:entry
      (atom:id ,(string-append config-entry-id-prefix (number->string id)))
      (atom:title ,url)
      (atom:updated ,(rfc-3339 mtime))
      (atom:published ,(rfc-3339 (if (null? ptime) ctime ptime)))
      (atom:link (@ (rel "related") (href ,url)))
      ,(atom-content type descr notes)
      ,@(query (map-rows (lambda (x) `(atom:category (@ (term ,(car x))))))
               (sql db "SELECT tag.name FROM tagrel
                        OUTER LEFT JOIN tag ON tagrel.tag_id=tag.id
                        WHERE url_id=? ORDER BY tag.name;")
               id)))
 
 (define (write-feed mtime title self rows)
   (write-string
     (serialize-sxml
       `(*TOP* (@ (*NAMESPACES* (atom "http://www.w3.org/2005/Atom")))
          (*PI* xml "version='1.0' encoding='utf-8'")
          (atom:feed
            (atom:title ,title)
            (atom:author
              (atom:name ,(if config-author-name
                              config-author-name
                              "Unknown Author"))
              ,@(if config-author-email `((atom:email ,config-author-email)) '())
              ,@(if config-author-uri `((atom:uri ,config-author-uri)) '()))
            (atom:id ,self)
            (atom:link (@ (rel "self") (href ,self)))
            (atom:updated ,(rfc-3339 mtime))
            ,@(map (lambda (row) (apply feed->sxml row)) rows)))
       ns-prefixes: '((*default* . "http://www.w3.org/2005/Atom")))))
 
 (define (generate-feed forced feed-id filename url selector title mtime)
   (let* ((rows (query fetch-rows
                       (sql db (string-append "SELECT id,url,type,description,
                                                      notes,ptime,ctime,mtime
                                               FROM entry " selector ";"))))
          (generate?
            (cond ((null? rows)
                    (when config-verbose
                      (write-line (conc "Feed " feed-id " is empty")))
                    #f)
                  ((any (cut = feed-id <>) dirty-feeds)
                    (when config-verbose
                      (write-line (conc "Generating feed " feed-id)))
                    #t)
                  (forced
                    (when config-verbose
                      (write-line (conc "Generating feed " feed-id
                                        " unconditionally")))
                    #t)
                  (else
                    (when config-verbose
                      (write-line (conc "Feed " feed-id
                                        " is already up to date")))
                    #t))))
     (when generate?
       (with-output-to-file filename
         (lambda () (write-feed (if (null? mtime) (list-ref (car rows) 7) mtime)
                                title url rows)))
       (set! dirty-feeds (delete! feed-id dirty-feeds =))
       (set! feed-cache
         (alist-update! feed-id
                        (map (lambda (row) (list (car row) (list-ref row 7)))
                             rows)
                        feed-cache =)))))
 
 (define (generate-feeds forced id-list)
   (for-each
     (lambda (row) (apply generate-feed forced row))
     (if (null? id-list)
         (query fetch-rows
                (sql db "SELECT id,filename,url,selector,title,mtime
                         FROM feed WHERE active=1;"))
         (map (lambda (id)
                (query fetch
                       (sql db "SELECT id,filename,url,selector,title,mtime
                                FROM feed WHERE id=?;")
                       id))
              id-list))))
 
 (defcmd (force-generate . args)
   "[feed-id ...]"
   "Generate unconditionally the given feeds, or all active feeds"
   (generate-feeds #t args))
 
 (defcmd (generate . args)
   "[feed-id ...]" "Generate if needed the given feeds, or all active feeds"
   (generate-feeds #f args))
 
 ;;;;;;;;;;;;;
 ;; Auto Add
 
 (define (auto-add lines)
   (unless arg-replay
     (trace `(auto-add ,lines))
     (let loop ((index 0) (urls '()))
       (let* ((start0 (substring-index-ci "https://" lines index))
              (start  (if start0 start0
                          (substring-index-ci "http://" lines index)))
              (end    (if start
                          (apply min
                            (filter identity
                              (list
                                (string-length lines)
                                (substring-index " " lines start)
                                (substring-index "\n" lines start))))
                          #f)))
         (cond (start
                 (loop end (cons (substring lines start end) urls)))
               ((null? urls)
                 (write-line (conc "Warning: no URL found")))
               (else
                 (for-each (lambda (url) (add-entry url lines)) urls)))))))
 
 ;;;;;;;;;;;;;;
 ;; Main loop
 
 (defcmd (replay filename)
   "filename" "Replay the given file"
   (let ((old-arg-replay arg-replay))
     (set! arg-replay #t)
     (load filename)
     (set! arg-replay old-arg-replay)))
 
 (define write-each-row
   (for-each-row
     (lambda (row) (if (= 1 (length row))
                       (write-line (->string (car row)))
                       (begin (write row) (newline))))))
 
 (define (write-query text . args)
    (apply query write-each-row (sql/transient db text) args))
 
 (defcmd (help)
   "" "Display this help"
   (for-each
     (lambda (row)
       (write-line (conc
         "("
         (car row)
         (if (zero? (string-length (cadr row))) "" " ")
         (cadr row)
         ")"))
       (write-line (conc "    " (caddr row))))
     cmd-list))
 
 (set! cmd-list (sort! cmd-list (lambda (r1 r2) (string<? (car r1) (car r2)))))
 
 (define completion-ptr cmd-list)
 (define new-completion #t)
 (define (completer prefix state)
   (when (zero? state)
     (set! completion-ptr cmd-list)
     (set! new-completion #t))
   (let ((buf (line-buffer)))
     (cond ((and (positive? (string-length buf))
                 (not (eqv? (string-ref buf 0) #\()))
             #f)
           ((substring-index " " buf)
             (let ((other-state (if new-completion 0 state)))
               (set! new-completion #f)
               (scheme-completer prefix other-state)))
           (else
             (let loop ()
               (cond ((null? completion-ptr)
                       #f)
                     ((starts-with? prefix (caar completion-ptr))
                       (let ((result (caar completion-ptr)))
                         (set! completion-ptr (cdr completion-ptr))
                         result))
                     (else
                         (set! completion-ptr (cdr completion-ptr))
                         (loop))))))))
 
 (define state 'general)
 (define (prompt)
   (string-append
     (if (null? protection-overrides)
         ""
         (string-append "!"
           (string-intersperse (map ->string protection-overrides) ",")))
     (cond ((eqv? state 'general) "> ")
           ((eqv? state 'in-command) "… ")
           (else "? "))))
 
 (define (interactive-main)
   (basic-quote-characters-set! "\"|")
   (completer-word-break-characters-set! "\"\'`;|()[] ")
   (completer-set! completer)
   (variable-bind! "blink-matching-paren" "on")
   (paren-blink-timeout-set! 200000)
 
   (let ((handler (signal-handler signal/int)))
     (set-signal-handler! signal/int (lambda (s) (cleanup-after-signal!)
                                                 (reset-after-signal!)
                                                 (handler s))))
   (on-exit reset-terminal!)
   (current-input-port (make-readline-port prompt))
 
   (let main-loop ()
     (let ((c (peek-char)))
       (cond ((eof-object? c))
             ((eqv? c #\()
               (set! state 'in-command)
               (handle-exceptions
                 exn
                 (begin
                   (print-error-message exn)
                   (print-call-chain))
                 (eval (read)))
               (set! state 'general)
               (main-loop))
             (else
               (let data-loop ((acc (list (read-line))))
                 (if (char-ready?)
                     (data-loop (cons (read-line) acc))
                     (let ((lines (reverse-string-append
                                    (map terminate-line acc))))
                       (when (positive? (string-length lines))
                         (auto-add lines))
                       (main-loop)))))))))
 
 (cond ((not arg-replay)
         (interactive-main))
       ((eqv? (string-ref arg-replay 0) #\()
         (eval (read (open-input-string arg-replay))))
       (else
         (load arg-replay)))