#!/bin/sh
# Tcl ignores the next line -*- tcl -*- \
exec wish "$0" -- "${1+$@}"

# Copyright (C) 2005 Paul Mackerras.  All rights reserved.
# This program is free software; it may be used, copied, modified
# and distributed under the terms of the GNU General Public Licence,
# either version 2, or (at your option) any later version.

# CVS $Revision: 1.2 $

set datemode 0
set boldnames 0
set revtreeargs {}

foreach arg $argv {
    switch -regexp -- $arg {
	"^$" { }
	"^-d" { set datemode 1 }
	"^-b" { set boldnames 1 }
	"^-.*" {
	    puts stderr "unrecognized option $arg"
	    exit 1
	}
	default {
	    lappend revtreeargs $arg
	}
    }
}

proc getcommits {rargs} {
    global commits parents cdate nparents children nchildren
    if {$rargs == {}} {
	set rargs HEAD
    }
    set commits {}
    foreach c [split [eval exec git-rev-tree $rargs] "\n"] {
	set i 0
	set cid {}
	foreach f $c {
	    if {$i == 0} {
		set d $f
	    } else {
		set id [lindex [split $f :] 0]
		if {![info exists nchildren($id)]} {
		    set children($id) {}
		    set nchildren($id) 0
		}
		if {$i == 1} {
		    set cid $id
		    lappend commits $id
		    set parents($id) {}
		    set cdate($id) $d
		    set nparents($id) 0
		} else {
		    lappend parents($cid) $id
		    incr nparents($cid)
		    incr nchildren($id)
		    lappend children($id) $cid
		}
	    }
	    incr i
	}
    }
}

proc readcommit {id} {
    global commitinfo commitsummary
    set inhdr 1
    set comment {}
    set headline {}
    set auname {}
    set audate {}
    set comname {}
    set comdate {}
    foreach line [split [exec git-cat-file commit $id] "\n"] {
	if {$inhdr} {
	    if {$line == {}} {
		set inhdr 0
	    } else {
		set tag [lindex $line 0]
		if {$tag == "author"} {
		    set x [expr {[llength $line] - 2}]
		    set audate [lindex $line $x]
		    set auname [lrange $line 1 [expr {$x - 1}]]
		} elseif {$tag == "committer"} {
		    set x [expr {[llength $line] - 2}]
		    set comdate [lindex $line $x]
		    set comname [lrange $line 1 [expr {$x - 1}]]
		}
	    }
	} else {
	    if {$comment == {}} {
		set headline $line
	    } else {
		append comment "\n"
	    }
	    append comment $line
	}
    }
    if {$audate != {}} {
	set audate [clock format $audate -format "%Y-%m-%d %H:%M:%S"]
    }
    if {$comdate != {}} {
	set comdate [clock format $comdate -format "%Y-%m-%d %H:%M:%S"]
    }
    set commitinfo($id) [list $comment $auname $audate $comname $comdate]
    set commitsummary($id) [list $headline $auname $audate]
}

proc makewindow {} {
    global canv linespc charspc ctext
    panedwindow .ctop -orient vertical
    frame .ctop.clist
    set canv .ctop.clist.canv
    canvas $canv -height [expr 30 * $linespc + 4] -width [expr 90 * $charspc] \
	-bg white -relief sunk -bd 1 \
	-yscrollincr $linespc -yscrollcommand ".ctop.clist.csb set"
    scrollbar .ctop.clist.csb -command "$canv yview" -highlightthickness 0
    pack .ctop.clist.csb -side right -fill y
    pack $canv -side bottom -fill both -expand 1
    .ctop add .ctop.clist
    #pack .ctop.clist -side top -fill both -expand 1
    set ctext .ctop.ctext
    text $ctext -bg white
    .ctop add .ctop.ctext
    #pack $ctext -side top -fill x -expand 1
    pack .ctop -side top -fill both -expand 1

    bind $canv <1> {selcanvline %x %y}
    bind $canv <B1-Motion> {selcanvline %x %y}
    bind $canv <ButtonRelease-4> "$canv yview scroll -5 u"
    bind $canv <ButtonRelease-5> "$canv yview scroll 5 u"
    bind $canv <2> "$canv scan mark 0 %y"
    bind $canv <B2-Motion> "$canv scan dragto 0 %y"
    bind . <Key-Prior> "$canv yview scroll -1 p"
    bind . <Key-Next> "$canv yview scroll 1 p"
    bind . <Key-Delete> "$canv yview scroll -1 p"
    bind . <Key-BackSpace> "$canv yview scroll -1 p"
    bind . <Key-space> "$canv yview scroll 1 p"
    bind . <Key-Up> "$canv yview scroll -1 u"
    bind . <Key-Down> "$canv yview scroll 1 u"
    bind . Q "set stopped 1; destroy ."
}

proc truncatetofit {str width font} {
    if {[font measure $font $str] <= $width} {
	return $str
    }
    set best 0
    set bad [string length $str]
    set tmp $str
    while {$best < $bad - 1} {
	set try [expr {int(($best + $bad) / 2)}]
	set tmp "[string range $str 0 [expr $try-1]]..."
	if {[font measure $font $tmp] <= $width} {
	    set best $try
	} else {
	    set bad $try
	}
    }
    return $tmp
}

proc drawgraph {start} {
    global parents children nparents nchildren commits
    global canv mainfont namefont canvx0 canvy0 linespc namex datex
    global datemode cdate
    global lineid linehtag linentag linedtag commitsummary

    set colors {green red blue magenta darkgrey brown orange}
    set ncolors [llength $colors]
    set nextcolor 0
    set colormap($start) [lindex $colors 0]
    foreach id $commits {
	set ncleft($id) $nchildren($id)
    }
    set todo [list $start]
    set level 0
    set canvy $canvy0
    set linestarty(0) $canvy
    set nullentry -1
    set lineno -1
    while 1 {
	incr lineno
	set nlines [llength $todo]
	set id [lindex $todo $level]
	set lineid($lineno) $id
	set actualparents {}
	foreach p $parents($id) {
	    if {[info exists ncleft($p)]} {
		incr ncleft($p) -1
		lappend actualparents $p
	    }
	}
	if {![info exists commitsummary($id)]} {
	    readcommit $id
	}
	set x [expr $canvx0 + $level * $linespc]
	set y2 [expr $canvy + $linespc]
	if {$linestarty($level) < $canvy} {
	    set t [$canv create line $x $linestarty($level) $x $canvy \
		       -width 2 -fill $colormap($id)]
	    $canv lower $t
	    set linestarty($level) $canvy
	}
	set t [$canv create oval [expr $x - 4] [expr $canvy - 4] \
		   [expr $x + 3] [expr $canvy + 3] \
		   -fill blue -outline black -width 1]
	$canv raise $t
	set xt [expr $canvx0 + $nlines * $linespc]
	set headline [lindex $commitsummary($id) 0]
	set name [lindex $commitsummary($id) 1]
	set date [lindex $commitsummary($id) 2]
	set headline [truncatetofit $headline [expr $namex-$xt-$linespc] \
			 $mainfont]
	set linehtag($lineno) [$canv create text $xt $canvy -anchor w \
				   -text $headline -font $mainfont ]
	set name [truncatetofit $name [expr $datex-$namex-$linespc] $namefont]
	set linentag($lineno) [$canv create text $namex $canvy -anchor w \
				   -text $name -font $namefont]
	set linedtag($lineno) [$canv create text $datex $canvy -anchor w \
				 -text $date -font $mainfont]
	if {!$datemode && [llength $actualparents] == 1} {
	    set p [lindex $actualparents 0]
	    if {$ncleft($p) == 0 && [lsearch -exact $todo $p] < 0} {
		set todo [lreplace $todo $level $level $p]
		set colormap($p) $colormap($id)
		set canvy $y2
		$canv conf -scrollregion [list 0 0 0 $canvy]
		update
		continue
	    }
	}

	set oldtodo $todo
	set oldlevel $level
	set lines {}
	for {set i 0} {$i < $nlines} {incr i} {
	    if {[lindex $todo $i] == {}} continue
	    set oldstarty($i) $linestarty($i)
	    if {$i != $level} {
		lappend lines [list $i [lindex $todo $i]]
	    }
	}
	unset linestarty
	if {$nullentry >= 0} {
	    set todo [lreplace $todo $nullentry $nullentry]
	    if {$nullentry < $level} {
		incr level -1
	    }
	}

	set badcolors [list $colormap($id)]
	foreach p $actualparents {
	    if {[info exists colormap($p)]} {
		lappend badcolors $colormap($p)
	    }
	}
	set todo [lreplace $todo $level $level]
	if {$nullentry > $level} {
	    incr nullentry -1
	}
	set i $level
	foreach p $actualparents {
	    set k [lsearch -exact $todo $p]
	    if {$k < 0} {
		set todo [linsert $todo $i $p]
		if {$nullentry >= $i} {
		    incr nullentry
		}
		if {$nparents($id) == 1 && $nparents($p) == 1
		    && $nchildren($p) == 1} {
		    set colormap($p) $colormap($id)
		} else {
		    for {set j 0} {$j <= $ncolors} {incr j} {
			if {[incr nextcolor] >= $ncolors} {
			    set nextcolor 0
			}
			set c [lindex $colors $nextcolor]
			# make sure the incoming and outgoing colors differ
			if {[lsearch -exact $badcolors $c] < 0} break
		    }
		    set colormap($p) $c
		    lappend badcolors $c
		}
	    }
	    lappend lines [list $oldlevel $p]
	}

	# choose which one to do next time around
	set todol [llength $todo]
	set level -1
	set latest {}
	for {set k $todol} {[incr k -1] >= 0} {} {
	    set p [lindex $todo $k]
	    if {$p == {}} continue
	    if {$ncleft($p) == 0} {
		if {$datemode} {
		    if {$latest == {} || $cdate($p) > $latest} {
			set level $k
			set latest $cdate($p)
		    }
		} else {
		    set level $k
		    break
		}
	    }
	}
	if {$level < 0} {
	    if {$todo != {}} {
		puts "ERROR: none of the pending commits can be done yet:"
		foreach p $todo {
		    puts "  $p"
		}
	    }
	    break
	}

	# If we are reducing, put in a null entry
	if {$todol < $nlines} {
	    if {$nullentry >= 0} {
		set i $nullentry
		while {$i < $todol
		       && [lindex $oldtodo $i] == [lindex $todo $i]} {
		    incr i
		}
	    } else {
		set i $oldlevel
		if {$level >= $i} {
		    incr i
		}
	    }
	    if {$i >= $todol} {
		set nullentry -1
	    } else {
		set nullentry $i
		set todo [linsert $todo $nullentry {}]
		if {$level >= $i} {
		    incr level
		}
	    }
	} else {
	    set nullentry -1
	}

	foreach l $lines {
	    set i [lindex $l 0]
	    set dst [lindex $l 1]
	    set j [lsearch -exact $todo $dst]
	    if {$i == $j} {
		set linestarty($i) $oldstarty($i)
		continue
	    }
	    set xi [expr {$canvx0 + $i * $linespc}]
	    set xj [expr {$canvx0 + $j * $linespc}]
	    set coords {}
	    if {$oldstarty($i) < $canvy} {
		lappend coords $xi $oldstarty($i)
	    }
	    lappend coords $xi $canvy
	    if {$j < $i - 1} {
		lappend coords [expr $xj + $linespc] $canvy
	    } elseif {$j > $i + 1} {
		lappend coords [expr $xj - $linespc] $canvy
	    }
	    lappend coords $xj $y2
	    set t [$canv create line $coords -width 2 -fill $colormap($dst)]
	    $canv lower $t
	    if {![info exists linestarty($j)]} {
		set linestarty($j) $y2
	    }
	}
	set canvy $y2
	$canv conf -scrollregion [list 0 0 0 $canvy]
	update
    }
}

proc selcanvline {x y} {
    global canv canvy0 ctext linespc selectedline
    global lineid linehtag linentag linedtag commitinfo
    set ymax [lindex [$canv cget -scrollregion] 3]
    set yfrac [lindex [$canv yview] 0]
    set y [expr {$y + $yfrac * $ymax}]
    set l [expr {int(($y - $canvy0) / $linespc + 0.5)}]
    if {$l < 0} {
	set l 0
    }
    if {[info exists selectedline] && $selectedline == $l} return
    if {![info exists lineid($l)] || ![info exists linehtag($l)]} return
    $canv select clear
    $canv select from $linehtag($l) 0
    $canv select to $linehtag($l) end
    set id $lineid($l)
    $ctext delete 0.0 end
    set info $commitinfo($id)
    $ctext insert end "Author: [lindex $info 1]  \t[lindex $info 2]\n"
    $ctext insert end "Committer: [lindex $info 3]  \t[lindex $info 4]\n"
    $ctext insert end "\n"
    $ctext insert end [lindex $info 0]
}

getcommits $revtreeargs

set mainfont {Helvetica 9}
set namefont $mainfont
if {$boldnames} {
    lappend namefont bold
}
set linespc [font metrics $mainfont -linespace]
set charspc [font measure $mainfont "m"]

set canvy0 [expr 3 + 0.5 * $linespc]
set canvx0 [expr 3 + 0.5 * $linespc]
set namex [expr 45 * $charspc]
set datex [expr 75 * $charspc]

makewindow

set start {}
foreach id $commits {
    if {$nchildren($id) == 0} {
	set start $id
	break
    }
}
if {$start != {}} {
    drawgraph $start
}