# visdiff.py - launch external visual diff tools
#
# Copyright 2009 Steve Borho <steve@borho.org>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2, incorporated herein by reference.

import os
import subprocess
import stat
import shutil
import threading
import tempfile
import re

from mercurial import hg, util, error, match, scmutil, copies

from tortoisehg.hgqt.i18n import _
from tortoisehg.util import hglib
from tortoisehg.hgqt import qtlib

from PyQt4.QtCore import *
from PyQt4.QtGui import *

# Match parent2 first, so 'parent1?' will match both parent1 and parent
_regex = '\$(parent2|parent1?|child|plabel1|plabel2|clabel|repo|phash1|phash2|chash)'

_nonexistant = _('[non-existant]')

# This global counter is incremented for each visual diff done in a session
# It ensures that the names for snapshots created do not collide.
_diffCount = 0

def snapshotset(repo, ctxs, sa, sb, copies, copyworkingdir = False):
    '''snapshot files from parent-child set of revisions'''
    ctx1a, ctx1b, ctx2 = ctxs
    mod_a, add_a, rem_a = sa
    mod_b, add_b, rem_b = sb

    global _diffCount
    _diffCount += 1

    if copies:
        sources = set(copies.values())
    else:
        sources = set()

    # Always make a copy of ctx1a
    files1a = sources | mod_a | rem_a | ((mod_b | add_b) - add_a)
    dir1a, fns_mtime1a = snapshot(repo, files1a, ctx1a)
    label1a = '@%d:%s' % (ctx1a.rev(), ctx1a)

    # Make a copy of ctx1b if relevant
    if ctx1b:
        files1b = sources | mod_b | rem_b | ((mod_a | add_a) - add_b)
        dir1b, fns_mtime1b = snapshot(repo, files1b, ctx1b)
        label1b = '@%d:%s' % (ctx1b.rev(), ctx1b)
    else:
        dir1b = None
        fns_mtime1b = []
        label1b = ''

    # Either make a copy of ctx2, or use working dir directly if relevant.
    files2 = mod_a | add_a | mod_b | add_b
    if ctx2.rev() is None:
        if copyworkingdir:
            dir2, fns_mtime2 = snapshot(repo, files2, ctx2)
        else:
            dir2 = repo.root
            fns_mtime2 = []
        # If ctx2 is working copy, use empty label.
        label2 = ''
    else:
        dir2, fns_mtime2 = snapshot(repo, files2, ctx2)
        label2 = '@%d:%s' % (ctx2.rev(), ctx2)

    dirs = [dir1a, dir1b, dir2]
    labels = [label1a, label1b, label2]
    fns_and_mtimes = [fns_mtime1a, fns_mtime1b, fns_mtime2]
    return dirs, labels, fns_and_mtimes

def snapshot(repo, files, ctx):
    '''snapshot files as of some revision'''
    dirname = os.path.basename(repo.root) or 'root'
    dirname += '.%d' % _diffCount
    if ctx.rev() is not None:
        dirname += '.%d' % ctx.rev()
    base = os.path.join(qtlib.gettempdir(), dirname)
    fns_and_mtime = []
    if not os.path.exists(base):
        os.makedirs(base)
    for fn in files:
        wfn = util.pconvert(fn)
        if not wfn in ctx:
            # File doesn't exist; could be a bogus modify
            continue
        dest = os.path.join(base, wfn)
        if os.path.exists(dest):
            # File has already been snapshot
            continue
        destdir = os.path.dirname(dest)
        try:
            if not os.path.isdir(destdir):
                os.makedirs(destdir)
            data = repo.wwritedata(wfn, ctx[wfn].data())
            f = open(dest, 'wb')
            f.write(data)
            f.close()
            if ctx.rev() is None:
                fns_and_mtime.append((dest, repo.wjoin(fn), 
                                    os.lstat(dest).st_mtime))
            else:
                # Make file read/only, to indicate it's static (archival) nature
                os.chmod(dest, stat.S_IREAD)
        except EnvironmentError:
            pass
    return base, fns_and_mtime

def launchtool(cmd, opts, replace, block):
    def quote(match):
        key = match.group()[1:]
        return util.shellquote(replace[key])
    if isinstance(cmd, unicode):
        cmd = hglib.fromunicode(cmd)
    lopts = []
    for opt in opts:
        if isinstance(opt, unicode):
            lopts.append(hglib.fromunicode(opt))
        else:
            lopts.append(opt)
    args = ' '.join(lopts)
    args = re.sub(_regex, quote, args)
    cmdline = util.shellquote(cmd) + ' ' + args
    cmdline = util.quotecommand(cmdline)
    try:
        proc = subprocess.Popen(cmdline, shell=True,
                                creationflags=qtlib.openflags,
                                stderr=subprocess.PIPE,
                                stdout=subprocess.PIPE,
                                stdin=subprocess.PIPE)
        if block:
            proc.communicate()
    except (OSError, EnvironmentError), e:
        QMessageBox.warning(None,
                _('Tool launch failure'),
                _('%s : %s') % (cmd, str(e)))

def filemerge(ui, fname, patchedfname):
    'Launch the preferred visual diff tool for two text files'
    detectedtools = hglib.difftools(ui)
    if not detectedtools:
        QMessageBox.warning(None,
                _('No diff tool found'),
                _('No visual diff tools were detected'))
        return None
    preferred = besttool(ui, detectedtools)
    diffcmd, diffopts, mergeopts = detectedtools[preferred]
    replace = dict(parent=fname, parent1=fname,
                   plabel1=fname + _('[working copy]'),
                   repo='', phash1='', phash2='', chash='',
                   child=patchedfname, clabel=_('[original]'))
    launchtool(diffcmd, diffopts, replace, True)


def besttool(ui, tools, force=None):
    'Select preferred or highest priority tool from dictionary'
    preferred = force or ui.config('tortoisehg', 'vdiff') or \
                         ui.config('ui', 'merge')
    if preferred and preferred in tools:
        return preferred
    pris = []
    for t in tools.keys():
        p = int(ui.config('merge-tools', t + '.priority', 0))
        pris.append((-p, t))
    tools = sorted(pris)
    return tools[0][1]


def visualdiff(ui, repo, pats, opts):
    revs = opts.get('rev', [])
    change = opts.get('change')

    try:
        ctx1b = None
        if change:
            ctx2 = repo[change]
            p = ctx2.parents()
            if len(p) > 1:
                ctx1a, ctx1b = p
            else:
                ctx1a = p[0]
        else:
            n1, n2 = scmutil.revpair(repo, revs)
            ctx1a, ctx2 = repo[n1], repo[n2]
            p = ctx2.parents()
            if not revs and len(p) > 1:
                ctx1b = p[1]
    except (error.LookupError, error.RepoError):
        QMessageBox.warning(None,
                       _('Unable to find changeset'),
                       _('You likely need to refresh this application'))
        return None

    pats = scmutil.expandpats(pats)
    m = match.match(repo.root, '', pats, None, None, 'relpath')
    n2 = ctx2.node()
    mod_a, add_a, rem_a = map(set, repo.status(ctx1a.node(), n2, m)[:3])
    if ctx1b:
        mod_b, add_b, rem_b = map(set, repo.status(ctx1b.node(), n2, m)[:3])
        cpy = copies.mergecopies(repo, ctx1a, ctx1b, ctx1a.ancestor(ctx1b))[0]
    else:
        cpy = copies.pathcopies(ctx1a, ctx2)
        mod_b, add_b, rem_b = set(), set(), set()
    MA = mod_a | add_a | mod_b | add_b
    MAR = MA | rem_a | rem_b
    if not MAR:
        QMessageBox.information(None,
                _('No file changes'),
                _('There are no file changes to view'))
        return None

    detectedtools = hglib.difftools(repo.ui)
    if not detectedtools:
        QMessageBox.warning(None,
                _('No diff tool found'),
                _('No visual diff tools were detected'))
        return None

    preferred = besttool(repo.ui, detectedtools, opts.get('tool'))

    # Build tool list based on diff-patterns matches
    toollist = set()
    patterns = repo.ui.configitems('diff-patterns')
    patterns = [(p, t) for p,t in patterns if t in detectedtools]
    for path in MAR:
        for pat, tool in patterns:
            mf = match.match(repo.root, '', [pat])
            if mf(path):
                toollist.add(tool)
                break
        else:
            toollist.add(preferred)

    cto = cpy.keys()
    for path in MAR:
        if path in cto:
            hascopies = True
            break
    else:
        hascopies = False
    force = repo.ui.configbool('tortoisehg', 'forcevdiffwin')
    if len(toollist) > 1 or (hascopies and len(MAR) > 1) or force:
        usewin = True
    else:
        preferred = toollist.pop()
        dirdiff = repo.ui.configbool('merge-tools', preferred + '.dirdiff')
        dir3diff = repo.ui.configbool('merge-tools', preferred + '.dir3diff')
        usewin = repo.ui.configbool('merge-tools', preferred + '.usewin')
        if not usewin and len(MAR) > 1:
            if ctx1b is not None:
                usewin = not dir3diff
            else:
                usewin = not dirdiff
    if usewin:
        # Multiple required tools, or tool does not support directory diffs
        sa = [mod_a, add_a, rem_a]
        sb = [mod_b, add_b, rem_b]
        dlg = FileSelectionDialog(repo, pats, ctx1a, sa, ctx1b, sb, ctx2, cpy)
        return dlg

    # We can directly use the selected tool, without a visual diff window
    diffcmd, diffopts, mergeopts = detectedtools[preferred]

    # Disable 3-way merge if there is only one parent or no tool support
    do3way = False
    if ctx1b:
        if mergeopts:
            do3way = True
            args = mergeopts
        else:
            args = diffopts
            if str(ctx1b.rev()) in revs:
                ctx1a = ctx1b
    else:
        args = diffopts

    def dodiff():
        assert not (hascopies and len(MAR) > 1), \
                'dodiff cannot handle copies when diffing dirs'

        sa = [mod_a, add_a, rem_a]
        sb = [mod_b, add_b, rem_b]
        ctxs = [ctx1a, ctx1b, ctx2]

        # If more than one file, diff on working dir copy.
        copyworkingdir = len(MAR) > 1
        dirs, labels, fns_and_mtimes = snapshotset(repo, ctxs, sa, sb, cpy,
                                                   copyworkingdir)
        dir1a, dir1b, dir2 = dirs
        label1a, label1b, label2 = labels
        fns_and_mtime = fns_and_mtimes[2]

        if len(MAR) > 1 and label2 == '':
            label2 = 'working files'

        def getfile(fname, dir, label):
            file = os.path.join(qtlib.gettempdir(), dir, fname)
            if os.path.isfile(file):
                return fname+label, file
            nullfile = os.path.join(qtlib.gettempdir(), 'empty')
            fp = open(nullfile, 'w')
            fp.close()
            return (hglib.fromunicode(_nonexistant, 'replace') + label,
                    nullfile)

        # If only one change, diff the files instead of the directories
        # Handle bogus modifies correctly by checking if the files exist
        if len(MAR) == 1:
            file2 = MAR.pop()
            file2local = util.localpath(file2)
            if file2 in cto:
                file1 = util.localpath(cpy[file2])
            else:
                file1 = file2
            label1a, dir1a = getfile(file1, dir1a, label1a)
            if do3way:
                label1b, dir1b = getfile(file1, dir1b, label1b)
            label2, dir2 = getfile(file2local, dir2, label2)
        if do3way:
            label1a += '[local]'
            label1b += '[other]'
            label2 += '[merged]'

        replace = dict(parent=dir1a, parent1=dir1a, parent2=dir1b,
                       plabel1=label1a, plabel2=label1b,
                       phash1=str(ctx1a), phash2=str(ctx1b),
                       repo=hglib.fromunicode(repo.displayname),
                       clabel=label2, child=dir2, chash=str(ctx2))
        launchtool(diffcmd, args, replace, True)

        # detect if changes were made to mirrored working files
        for copy_fn, working_fn, mtime in fns_and_mtime:
            try:
                if os.lstat(copy_fn).st_mtime != mtime:
                    ui.debug('file changed while diffing. '
                            'Overwriting: %s (src: %s)\n' % (working_fn, copy_fn))
                    util.copyfile(copy_fn, working_fn)
            except EnvironmentError:
                pass # Ignore I/O errors or missing files

    def dodiffwrapper():
        try:
            dodiff()
        finally:
            # cleanup happens atexit
            ui.note('cleaning up temp directory\n')

    if opts.get('mainapp'):
        dodiffwrapper()
    else:
        # We are not the main application, so this must be done in a
        # background thread
        thread = threading.Thread(target=dodiffwrapper, name='visualdiff')
        thread.setDaemon(True)
        thread.start()

class FileSelectionDialog(QDialog):
    'Dialog for selecting visual diff candidates'
    def __init__(self, repo, pats, ctx1a, sa, ctx1b, sb, ctx2, cpy):
        'Initialize the Dialog'
        QDialog.__init__(self)

        self.setWindowIcon(qtlib.geticon('visualdiff'))

        if ctx2.rev() is None:
            title = _('working changes')
        elif ctx1a == ctx2.parents()[0]:
            title = _('changeset %d:%s') % (ctx2.rev(), ctx2)
        else:
            title = _('revisions %d:%s to %d:%s') \
                % (ctx1a.rev(), ctx1a, ctx2.rev(), ctx2)
        title = _('Visual Diffs - ') + title
        if pats:
            title += _(' filtered')
        self.setWindowTitle(title)

        self.resize(650, 250)
        self.reponame = hglib.fromunicode(repo.displayname)

        self.ctxs = (ctx1a, ctx1b, ctx2)
        self.filesets = (sa, sb)
        self.copies = cpy
        self.repo = repo
        self.curFile = None

        layout = QVBoxLayout()
        self.setLayout(layout)

        lbl = QLabel(_('Temporary files are removed when this dialog '
                       'is closed'))
        layout.addWidget(lbl)

        list = QListWidget()
        layout.addWidget(list)
        self.list = list
        list.itemActivated.connect(self.itemActivated)

        tools = hglib.difftools(repo.ui)
        preferred = besttool(repo.ui, tools)
        self.diffpath, self.diffopts, self.mergeopts = tools[preferred]
        self.tools = tools
        self.preferred = preferred

        if len(tools) > 1:
            hbox = QHBoxLayout()
            combo = QComboBox()
            lbl = QLabel(_('Select Tool:'))
            lbl.setBuddy(combo)
            hbox.addWidget(lbl)
            hbox.addWidget(combo, 1)
            layout.addLayout(hbox)
            for i, name in enumerate(tools.iterkeys()):
                combo.addItem(name)
                if name == preferred:
                    defrow = i
            combo.setCurrentIndex(defrow)

            list.currentRowChanged.connect(self.updateToolSelection)
            combo.currentIndexChanged['QString'].connect(self.onToolSelected)
            self.toolCombo = combo

        BB = QDialogButtonBox
        bb = BB()
        layout.addWidget(bb)

        if ctx2.rev() is None:
            pass
            # Do not offer directory diffs when the working directory
            # is being referenced directly
        elif ctx1b:
            self.p1button = bb.addButton(_('Dir diff to p1'), BB.ActionRole)
            self.p1button.pressed.connect(self.p1dirdiff)
            self.p2button = bb.addButton(_('Dir diff to p2'), BB.ActionRole)
            self.p2button.pressed.connect(self.p2dirdiff)
            self.p3button = bb.addButton(_('3-way dir diff'), BB.ActionRole)
            self.p3button.pressed.connect(self.threewaydirdiff)
        else:
            self.dbutton = bb.addButton(_('Directory diff'), BB.ActionRole)
            self.dbutton.pressed.connect(self.p1dirdiff)

        self.updateDiffButtons(preferred)

        QShortcut(QKeySequence('CTRL+D'), self.list, self.activateCurrent)
        QTimer.singleShot(0, self.fillmodel)

    @pyqtSlot()
    def fillmodel(self):
        repo = self.repo
        sa, sb = self.filesets
        self.dirs, self.revs = snapshotset(repo, self.ctxs, sa, sb, self.copies)[:2]

        def get_status(file, mod, add, rem):
            if file in mod:
                return 'M'
            if file in add:
                return 'A'
            if file in rem:
                return 'R'
            return ' '

        mod_a, add_a, rem_a = sa
        for f in sorted(mod_a | add_a | rem_a):
            status = get_status(f, mod_a, add_a, rem_a)
            row = QString('%s %s' % (status, hglib.tounicode(f)))
            self.list.addItem(row)

    @pyqtSlot(QString)
    def onToolSelected(self, tool):
        'user selected a tool from the tool combo'
        tool = hglib.fromunicode(tool)
        assert tool in self.tools
        self.diffpath, self.diffopts, self.mergeopts = self.tools[tool]
        self.updateDiffButtons(tool)

    @pyqtSlot(int)
    def updateToolSelection(self, row):
        'user selected a file, pick an appropriate tool from combo'
        if row == -1:
            return

        repo = self.repo
        patterns = repo.ui.configitems('diff-patterns')
        patterns = [(p, t) for p,t in patterns if t in self.tools]

        fname = self.list.item(row).text()[2:]
        fname = hglib.fromunicode(fname)
        if self.curFile == fname:
            return
        self.curFile = fname
        for pat, tool in patterns:
            mf = match.match(repo.root, '', [pat])
            if mf(fname):
                selected = tool
                break
        else:
            selected = self.preferred
        for i, name in enumerate(self.tools.iterkeys()):
            if name == selected:
                self.toolCombo.setCurrentIndex(i)

    def activateCurrent(self):
        'CTRL+D has been pressed'
        row = self.list.currentRow()
        if row >= 0:
            self.launch(self.list.item(row).text()[2:])

    def itemActivated(self, item):
        'A QListWidgetItem has been activated'
        self.launch(item.text()[2:])

    def updateDiffButtons(self, tool):
        if hasattr(self, 'p1button'):
            d2 = self.repo.ui.configbool('merge-tools', tool + '.dirdiff')
            d3 = self.repo.ui.configbool('merge-tools', tool + '.dir3diff')
            self.p1button.setEnabled(d2)
            self.p2button.setEnabled(d2)
            self.p3button.setEnabled(d3)
        elif hasattr(self, 'dbutton'):
            d2 = self.repo.ui.configbool('merge-tools', tool + '.dirdiff')
            self.dbutton.setEnabled(d2)

    def launch(self, fname):
        fname = hglib.fromunicode(fname)
        source = self.copies.get(fname, None)
        dir1a, dir1b, dir2 = self.dirs
        rev1a, rev1b, rev2 = self.revs
        ctx1a, ctx1b, ctx2 = self.ctxs

        def getfile(ctx, dir, fname, source):
            m = ctx.manifest()
            if fname in m:
                path = os.path.join(dir, util.localpath(fname))
                return fname, path
            elif source and source in m:
                path = os.path.join(dir, util.localpath(source))
                return source, path
            else:
                nullfile = os.path.join(qtlib.gettempdir(), 'empty')
                fp = open(nullfile, 'w')
                fp.close()
                return hglib.fromunicode(_nonexistant, 'replace'), nullfile

        local, file1a = getfile(ctx1a, dir1a, fname, source)
        if ctx1b:
            other, file1b = getfile(ctx1b, dir1b, fname, source)
        else:
            other, file1b = fname, None
        fname, file2 = getfile(ctx2, dir2, fname, None)

        label1a = local+rev1a
        label1b = other+rev1b
        label2 = fname+rev2
        if ctx1b:
            label1a += '[local]'
            label1b += '[other]'
            label2 += '[merged]'

        # Function to quote file/dir names in the argument string
        replace = dict(parent=file1a, parent1=file1a, plabel1=label1a,
                       parent2=file1b, plabel2=label1b,
                       repo=self.reponame,
                       phash1=str(ctx1a), phash2=str(ctx1b), chash=str(ctx2),
                       clabel=label2, child=file2)
        args = ctx1b and self.mergeopts or self.diffopts
        launchtool(self.diffpath, args, replace, False)

    def p1dirdiff(self):
        dir1a, dir1b, dir2 = self.dirs
        rev1a, rev1b, rev2 = self.revs
        ctx1a, ctx1b, ctx2 = self.ctxs

        replace = dict(parent=dir1a, parent1=dir1a, plabel1=rev1a,
                       repo=self.reponame,
                       phash1=str(ctx1a), phash2=str(ctx1b), chash=str(ctx2),
                       parent2='', plabel2='', clabel=rev2, child=dir2)
        launchtool(self.diffpath, self.diffopts, replace, False)

    def p2dirdiff(self):
        dir1a, dir1b, dir2 = self.dirs
        rev1a, rev1b, rev2 = self.revs
        ctx1a, ctx1b, ctx2 = self.ctxs

        replace = dict(parent=dir1b, parent1=dir1b, plabel1=rev1b,
                       repo=self.reponame,
                       phash1=str(ctx1a), phash2=str(ctx1b), chash=str(ctx2),
                       parent2='', plabel2='', clabel=rev2, child=dir2)
        launchtool(self.diffpath, self.diffopts, replace, False)

    def threewaydirdiff(self):
        dir1a, dir1b, dir2 = self.dirs
        rev1a, rev1b, rev2 = self.revs
        ctx1a, ctx1b, ctx2 = self.ctxs

        replace = dict(parent=dir1a, parent1=dir1a, plabel1=rev1a,
                       repo=self.reponame,
                       phash1=str(ctx1a), phash2=str(ctx1b), chash=str(ctx2),
                       parent2=dir1b, plabel2=rev1b, clabel=dir2, child=rev2)
        launchtool(self.diffpath, self.mergeopts, replace, False)
