# incremental search panel
# based on code from gitk, Copyright (C) Paul Mackerras

class searchbar {

field w
field ctext

field searchstring   {}
field casesensitive  1
field searchdirn     -forwards

field smarktop
field smarkbot

constructor new {i_w i_text args} {
        set w      $i_w
        set ctext  $i_text

        frame  $w
        label  $w.l       -text [mc Find:]
        button $w.bn      -text [mc Next] -command [cb find_next]
        button $w.bp      -text [mc Prev] -command [cb find_prev]
        checkbutton $w.cs -text [mc Case-Sensitive] \
                -variable ${__this}::casesensitive -command [cb _incrsearch]
        entry  $w.ent -textvariable ${__this}::searchstring -background lightgreen
        pack   $w.l   -side left
        pack   $w.cs  -side right
        pack   $w.bp  -side right
        pack   $w.bn  -side right
        pack   $w.ent -side left -expand 1 -fill x

        eval grid conf $w -sticky we $args
        grid remove $w

        trace add variable searchstring write [cb _incrsearch_cb]
        
        bind $w <Destroy> [cb delete_this]
        return $this
}

method show {} {
        if {![winfo ismapped $w]} {
                grid $w
        }
        focus -force $w.ent
}

method hide {} {
        if {[winfo ismapped $w]} {
                focus $ctext
                grid remove $w
        }
}

method _get_new_anchor {} {
        # use start of selection if it is visible,
        # or the bounds of the visible area
        set top    [$ctext index @0,0]
        set bottom [$ctext index @0,[winfo height $ctext]]
        set sel    [$ctext tag ranges sel]
        if {$sel ne {}} {
                set spos [lindex $sel 0]
                if {[lindex $spos 0] >= [lindex $top 0] &&
                    [lindex $spos 0] <= [lindex $bottom 0]} {
                        return $spos
                }
        }
        if {$searchdirn eq "-forwards"} {
                return $top
        } else {
                return $bottom
        }
}

method _get_wrap_anchor {dir} {
        if {$dir eq "-forwards"} {
                return 1.0
        } else {
                return end
        }
}

method _do_search {start {mlenvar {}} {dir {}} {endbound {}}} {
        set cmd [list $ctext search]
        if {$mlenvar ne {}} {
                upvar $mlenvar mlen
                lappend cmd -count mlen
        }
        if {!$casesensitive} {
                lappend cmd -nocase
        }
        if {$dir eq {}} {
                set dir $searchdirn
        }
        lappend cmd $dir -- $searchstring
        if {$endbound ne {}} {
                set here [eval $cmd [list $start] [list $endbound]]
        } else {
                set here [eval $cmd [list $start]]
                if {$here eq {}} {
                        set here [eval $cmd [_get_wrap_anchor $this $dir]]
                }
        }
        return $here
}

method _incrsearch_cb {name ix op} {
        after idle [cb _incrsearch]
}

method _incrsearch {} {
        $ctext tag remove found 1.0 end
        if {[catch {$ctext index anchor}]} {
                $ctext mark set anchor [_get_new_anchor $this]
        }
        if {$searchstring ne {}} {
                set here [_do_search $this anchor mlen]
                if {$here ne {}} {
                        $ctext see $here
                        $ctext tag remove sel 1.0 end
                        $ctext tag add sel $here "$here + $mlen c"
                        $w.ent configure -background lightgreen
                        _set_marks $this 1
                } else {
                        $w.ent configure -background lightpink
                }
        }
}

method find_prev {} {
        find_next $this -backwards
}

method find_next {{dir -forwards}} {
        focus $w.ent
        $w.ent icursor end
        set searchdirn $dir
        $ctext mark unset anchor
        if {$searchstring ne {}} {
                set start [_get_new_anchor $this]
                if {$dir eq "-forwards"} {
                        set start "$start + 1c"
                }
                set match [_do_search $this $start mlen]
                $ctext tag remove sel 1.0 end
                if {$match ne {}} {
                        $ctext see $match
                        $ctext tag add sel $match "$match + $mlen c"
                }
        }
}

method _mark_range {first last} {
        set mend $first.0
        while {1} {
                set match [_do_search $this $mend mlen -forwards $last.end]
                if {$match eq {}} break
                set mend "$match + $mlen c"
                $ctext tag add found $match $mend
        }
}

method _set_marks {doall} {
        set topline [lindex [split [$ctext index @0,0] .] 0]
        set botline [lindex [split [$ctext index @0,[winfo height $ctext]] .] 0]
        if {$doall || $botline < $smarktop || $topline > $smarkbot} {
                # no overlap with previous
                _mark_range $this $topline $botline
                set smarktop $topline
                set smarkbot $botline
        } else {
                if {$topline < $smarktop} {
                        _mark_range $this $topline [expr {$smarktop-1}]
                        set smarktop $topline
                }
                if {$botline > $smarkbot} {
                        _mark_range $this [expr {$smarkbot+1}] $botline
                        set smarkbot $botline
                }
        }
}

method scrolled {} {
        if {$searchstring ne {}} {
                after idle [cb _set_marks 0]
        }
}

}