# git-gui spellchecking support through ispell/aspell
# Copyright (C) 2008 Shawn Pearce

class spellcheck {

field s_fd      {} ; # pipe to ispell/aspell
field s_version {} ; # ispell/aspell version string
field s_lang    {} ; # current language code

field w_text      ; # text widget we are spelling
field w_menu      ; # context menu for the widget
field s_menuidx 0 ; # last index of insertion into $w_menu

field s_i           {} ; # timer registration for _run callbacks
field s_clear        0 ; # did we erase mispelled tags yet?
field s_seen    [list] ; # lines last seen from $w_text in _run
field s_checked [list] ; # lines already checked
field s_pending [list] ; # [$line $data] sent to ispell/aspell
field s_suggest        ; # array, list of suggestions, keyed by misspelling

constructor init {pipe_fd ui_text ui_menu} {
        set w_text $ui_text
        set w_menu $ui_menu
        array unset s_suggest

        _connect $this $pipe_fd
        return $this
}

method _connect {pipe_fd} {
        fconfigure $pipe_fd \
                -encoding utf-8 \
                -eofchar {} \
                -translation lf

        if {[gets $pipe_fd s_version] <= 0} {
                close $pipe_fd
                error [mc "Spell checker sliently failed on startup"]
        }
        if {{@(#) } ne [string range $s_version 0 4]} {
                close $pipe_fd
                error [strcat [mc "Unrecognized spell checker"] ": $s_version"]
        }
        set s_version [string range $s_version 5 end]

        puts $pipe_fd !             ; # enable terse mode
        puts $pipe_fd {$$cr master} ; # fetch the language
        flush $pipe_fd

        gets $pipe_fd s_lang
        regexp {[/\\]([^/\\]+)\.[^\.]+$} $s_lang _ s_lang

        if {$::default_config(gui.spellingdictionary) eq {}
         && [get_config gui.spellingdictionary] eq {}} {
                set ::default_config(gui.spellingdictionary) $s_lang
        }

        if {$s_fd ne {}} {
                catch {close $s_fd}
        }
        set s_fd $pipe_fd

        fconfigure $s_fd -blocking 0
        fileevent $s_fd readable [cb _read]

        $w_text tag conf misspelled \
                -foreground red \
                -underline 1
        bind_button3 $w_text [cb _popup_suggest %X %Y @%x,%y]

        array unset s_suggest
        set s_seen    [list]
        set s_checked [list]
        set s_pending [list]
        _run $this
}

method lang {{n {}}} {
        if {$n ne {} && $s_lang ne $n} {
                set spell_cmd [list |]
                lappend spell_cmd aspell
                lappend spell_cmd --master=$n
                lappend spell_cmd --mode=none
                lappend spell_cmd --encoding=UTF-8
                lappend spell_cmd pipe
                _connect $this [open $spell_cmd r+]
        }
        return $s_lang
}

method version {} {
        if {$s_version ne {}} {
                return "$s_version, $s_lang"
        }
        return {}
}

method stop {} {
        while {$s_menuidx > 0} {
                $w_menu delete 0
                incr s_menuidx -1
        }
        $w_text tag delete misspelled

        catch {close $s_fd}
        catch {after cancel $s_i}
        set s_fd {}
        set s_i {}
        set s_lang {}
}

method _popup_suggest {X Y pos} {
        while {$s_menuidx > 0} {
                $w_menu delete 0
                incr s_menuidx -1
        }

        set b_loc [$w_text index "$pos wordstart"]
        set e_loc [_wordend $this $b_loc]
        set orig  [$w_text get $b_loc $e_loc]
        set tags  [$w_text tag names $b_loc]

        if {[lsearch -exact $tags misspelled] >= 0} {
                if {[info exists s_suggest($orig)]} {
                        set cnt 0
                        foreach s $s_suggest($orig) {
                                if {$cnt < 5} {
                                        $w_menu insert $s_menuidx command \
                                                -label $s \
                                                -command [cb _replace $b_loc $e_loc $s]
                                        incr s_menuidx
                                        incr cnt
                                } else {
                                        break
                                }
                        }
                } else {
                        $w_menu insert $s_menuidx command \
                                -label [mc "No Suggestions"] \
                                -state disabled
                        incr s_menuidx
                }
                $w_menu insert $s_menuidx separator
                incr s_menuidx
        }

        $w_text mark set saved-insert insert
        tk_popup $w_menu $X $Y
}

method _replace {b_loc e_loc word} {
        $w_text configure -autoseparators 0
        $w_text edit separator

        $w_text delete $b_loc $e_loc
        $w_text insert $b_loc $word

        $w_text edit separator
        $w_text configure -autoseparators 1
        $w_text mark set insert saved-insert
}

method _restart_timer {} {
        set s_i [after 300 [cb _run]]
}

proc _match_length {max_line arr_name} {
        upvar $arr_name a

        if {[llength $a] > $max_line} {
                set a [lrange $a 0 $max_line]
        }
        while {[llength $a] <= $max_line} {
                lappend a {}
        }
}

method _wordend {pos} {
        set pos  [$w_text index "$pos wordend"]
        set tags [$w_text tag names $pos]
        while {[lsearch -exact $tags misspelled] >= 0} {
                set pos  [$w_text index "$pos +1c"]
                set tags [$w_text tag names $pos]
        }
        return $pos
}

method _run {} {
        set cur_pos  [$w_text index {insert -1c}]
        set cur_line [lindex [split $cur_pos .] 0]
        set max_line [lindex [split [$w_text index end] .] 0]
        _match_length $max_line s_seen
        _match_length $max_line s_checked

        # Nothing in the message buffer?  Nothing to spellcheck.
        #
        if {$cur_line == 1
         && $max_line == 2
         && [$w_text get 1.0 end] eq "\n"} {
                array unset s_suggest
                _restart_timer $this
                return
        }

        set active 0
        for {set n 1} {$n <= $max_line} {incr n} {
                set s [$w_text get "$n.0" "$n.end"]

                # Don't spellcheck the current line unless we are at
                # a word boundary.  The user might be typing on it.
                #
                if {$n == $cur_line
                 && ![regexp {^\W$} [$w_text get $cur_pos insert]]} {

                        # If the current word is mispelled remove the tag
                        # but force a spellcheck later.
                        #
                        set tags [$w_text tag names $cur_pos]
                        if {[lsearch -exact $tags misspelled] >= 0} {
                                $w_text tag remove misspelled \
                                        "$cur_pos wordstart" \
                                        [_wordend $this $cur_pos]
                                lset s_seen    $n $s
                                lset s_checked $n {}
                        }

                        continue
                }

                if {[lindex $s_seen    $n] eq $s
                 && [lindex $s_checked $n] ne $s} {
                        # Don't send empty lines to Aspell it doesn't check them.
                        #
                        if {$s eq {}} {
                                lset s_checked $n $s
                                continue
                        }

                        # Don't send typical s-b-o lines as the emails are
                        # almost always misspelled according to Aspell.
                        #
                        if {[regexp -nocase {^[a-z-]+-by:.*<.*@.*>$} $s]} {
                                $w_text tag remove misspelled "$n.0" "$n.end"
                                lset s_checked $n $s
                                continue
                        }

                        puts $s_fd ^$s
                        lappend s_pending [list $n $s]
                        set active 1
                } else {
                        # Delay until another idle loop to make sure we don't
                        # spellcheck lines the user is actively changing.
                        #
                        lset s_seen $n $s
                }
        }

        if {$active} {
                set s_clear 1
                flush $s_fd
        } else {
                _restart_timer $this
        }
}

method _read {} {
        while {[gets $s_fd line] >= 0} {
                set lineno [lindex $s_pending 0 0]

                if {$s_clear} {
                        $w_text tag remove misspelled "$lineno.0" "$lineno.end"
                        set s_clear 0
                }

                if {$line eq {}} {
                        lset s_checked $lineno [lindex $s_pending 0 1]
                        set s_pending [lrange $s_pending 1 end]
                        set s_clear 1
                        continue
                }

                set sugg [list]
                switch -- [string range $line 0 1] {
                {& } {
                        set line [split [string range $line 2 end] :]
                        set info [split [lindex $line 0] { }]
                        set orig [lindex $info 0]
                        set offs [lindex $info 2]
                        foreach s [split [lindex $line 1] ,] {
                                lappend sugg [string range $s 1 end]
                        }
                }
                {# } {
                        set info [split [string range $line 2 end] { }]
                        set orig [lindex $info 0]
                        set offs [lindex $info 1]
                }
                default {
                        puts stderr "<spell> $line"
                        continue
                }
                }

                incr offs -1
                set b_loc "$lineno.$offs"
                set e_loc [$w_text index "$lineno.$offs wordend"]
                set curr [$w_text get $b_loc $e_loc]

                # At least for English curr = "bob", orig = "bob's"
                # so Tk didn't include the 's but Aspell did.  We
                # try to round out the word.
                #
                while {$curr ne $orig
                 && [string equal -length [string length $curr] $curr $orig]} {
                        set n_loc  [$w_text index "$e_loc +1c"]
                        set n_curr [$w_text get $b_loc $n_loc]
                        if {$n_curr eq $curr} {
                                break
                        }
                        set curr  $n_curr
                        set e_loc $n_loc
                }

                if {$curr eq $orig} {
                        $w_text tag add misspelled $b_loc $e_loc
                        if {[llength $sugg] > 0} {
                                set s_suggest($orig) $sugg
                        } else {
                                unset -nocomplain s_suggest($orig)
                        }
                } else {
                        unset -nocomplain s_suggest($orig)
                }
        }

        fconfigure $s_fd -block 1
        if {[eof $s_fd]} {
                if {![catch {close $s_fd} err]} {
                        set err [mc "Unexpected EOF from spell checker"]
                }
                catch {after cancel $s_i}
                $w_text tag remove misspelled 1.0 end
                error_popup [strcat [mc "Spell Checker Failed"] "\n\n" $err]
                return
        }
        fconfigure $s_fd -block 0

        if {[llength $s_pending] == 0} {
                _restart_timer $this
        }
}

proc available_langs {} {
        set langs [list]
        catch {
                set fd [open [list | aspell dump dicts] r]
                while {[gets $fd line] >= 0} {
                        if {$line eq {}} continue
                        lappend langs $line
                }
                close $fd
        }
        return $langs
}

}