#!/usr/bin/env python
#
# Minimal support for git commands on an hg repository
#
# Copyright 2005 Chris Mason <mason@suse.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import time, sys, signal
from mercurial import hg, mdiff, fancyopts, commands, ui
    
def difftree(args, ui, repo):
    def __difftree(repo, files = None, node1 = None, node2 = None):
        def date(c):
            return time.asctime(time.gmtime(float(c[2].split(' ')[0])))

        if node2:
            change = repo.changelog.read(node2)
            mmap2 = repo.manifest.read(change[0])
            (c, a, d, u) = repo.changes(node1, node2)
            def read(f): return repo.file(f).read(mmap2[f])
            date2 = date(change)
        else:
            date2 = time.asctime()
            (c, a, d, u) = repo.diffdir(repo.root, node1)
            if not node1:
                node1 = repo.dirstate.parents()[0]
            def read(f): return file(os.path.join(repo.root, f)).read()

        change = repo.changelog.read(node1)
        mmap = repo.manifest.read(change[0])
        date1 = date(change)
        empty = "0" * 40;

        if files:
            c, a, d = map(lambda x: filterfiles(files, x), (c, a, d))

        for f in c:
            # TODO get file permissions
            print ":100664 100664 %s %s M\t%s\t%s" % (hg.hex(mmap[f]), 
                                                      hg.hex(mmap2[f]), f, f)
        for f in a:
            print ":000000 100664 %s %s N\t%s\t%s" % (empty, hg.hex(mmap2[f]), f, f)
        for f in d:
            print ":100664 000000 %s %s D\t%s\t%s" % (hg.hex(mmap[f]), empty, f, f)
    ##

    revs = []
    if args:
        doptions = {}
        opts = [('p', 'patch', None, 'patch'),
                ('r', 'recursive', None, 'recursive')]
        args = fancyopts.fancyopts(args, opts, doptions)

    if len(args) < 2:
        help()
        sys.exit(1)
    revs.append(repo.lookup(args[0]))
    revs.append(repo.lookup(args[1]))
    args = args[2:]
    if doptions['patch']:
        commands.dodiff(sys.stdout, ui, repo, args, *revs)
    else:
        __difftree(repo, args, *revs)

def catcommit(repo, n, prefix):
    nlprefix = '\n' + prefix;
    changes = repo.changelog.read(n)
    (p1, p2) = repo.changelog.parents(n)
    (h, h1, h2) = map(hg.hex, (n, p1, p2))
    (i1, i2) = map(repo.changelog.rev, (p1, p2))
    print "tree %s" % (h)
    if i1 != -1: print "%sparent %s" % (prefix, h1)
    if i2 != -1: print "%sparent %s" % (prefix, h2)
    date_ar = changes[2].split(' ')
    date = int(float(date_ar[0]))
    print "%sauthor <%s> %s %s" % (prefix, changes[1], date, date_ar[1])
    print "%scommitter <%s> %s %s" % (prefix, changes[1], date, date_ar[1])
    print prefix
    if prefix != "":
        print "%s%s" % (prefix, changes[4].replace('\n', nlprefix).strip())
    else:
        print changes[4]

def catfile(args, ui, repo):
    doptions = {}
    opts = [('s', 'stdin', None, 'stdin')]
    args = fancyopts.fancyopts(args, opts, doptions)

    # in stdin mode, every line except the commit is prefixed with two
    # spaces.  This way the our caller can find the commit without magic
    # strings
    #
    prefix = ""
    if doptions['stdin']:
        try:
            (type, r) = raw_input().split(' ');
            prefix = "  "
        except EOFError:
            return

    else:
        if len(args) < 2:
            help()
            sys.exit(1)
        type = args[0]
        r = args[1]

    while r:
        if type != "commit":
            sys.stderr.write("aborting hg cat-file only understands commits\n")
            sys.exit(1);
        n = repo.lookup(r)
        catcommit(repo, n, prefix)
        if doptions['stdin']:
            try:
                (type, r) = raw_input().split(' ');
            except EOFError:
                break
        else:
            break

# git rev-tree is a confusing thing.  You can supply a number of
# commit sha1s on the command line, and it walks the commit history
# telling you which commits are reachable from the supplied ones via
# a bitmask based on arg position.
# you can specify a commit to stop at by starting the sha1 with ^
def revtree(args, repo, full="tree", maxnr=0):
    # calculate and return the reachability bitmask for sha
    def is_reachable(ar, reachable, sha):
        if len(ar) == 0:
            return 1
        mask = 0
        for i in range(len(ar)):
            if sha in reachable[i]:
                mask |= 1 << i

        return mask

    reachable = []
    stop_sha1 = []
    want_sha1 = []
    count = 0

    # figure out which commits they are asking for and which ones they
    # want us to stop on
    for i in range(len(args)):
        if args[i].startswith('^'):
            s = repo.lookup(args[i][1:])
            stop_sha1.append(s)
            want_sha1.append(s)
        elif args[i] != 'HEAD':
            want_sha1.append(repo.lookup(args[i]))

    # calculate the graph for the supplied commits
    for i in range(len(want_sha1)):
        reachable.append({});
        n = want_sha1[i];
        visit = [n];
        reachable[i][n] = 1
        while visit:
            n = visit.pop(0)
            if n in stop_sha1:
                break
            for p in repo.changelog.parents(n):
                if p not in reachable[i]:
                    reachable[i][p] = 1
                    visit.append(p)
                if p in stop_sha1:
                    break

    # walk the repository looking for commits that are in our
    # reachability graph
    for i in range(repo.changelog.count()-1, -1, -1):
        n = repo.changelog.node(i)
        mask = is_reachable(want_sha1, reachable, n)
        if mask:
            if not full:
                print hg.hex(n)
            elif full is "commit":
                print hg.hex(n)
                catcommit(repo, n, '  ')
            else:
                changes = repo.changelog.read(n)
                (p1, p2) = repo.changelog.parents(n)
                (h, h1, h2) = map(hg.hex, (n, p1, p2))
                (i1, i2) = map(repo.changelog.rev, (p1, p2))

                date = changes[2].split(' ')[0]
                print "%s %s:%s" % (date, h, mask),
                mask = is_reachable(want_sha1, reachable, p1)
                if i1 != -1 and mask > 0:
                    print "%s:%s " % (h1, mask),
                mask = is_reachable(want_sha1, reachable, p2)
                if i2 != -1 and mask > 0:
                    print "%s:%s " % (h2, mask),
                print ""
            if maxnr and count >= maxnr:
                break
            count += 1

# git rev-list tries to order things by date, and has the ability to stop
# at a given commit without walking the whole repo.  TODO add the stop
# parameter
def revlist(args, repo):
    doptions = {}
    opts = [('c', 'commit', None, 'commit'),
            ('n', 'max-nr', 0, 'max-nr')]
    args = fancyopts.fancyopts(args, opts, doptions)
    if doptions['commit']:
        full = "commit"
    else:
        full = None
    for i in range(1, len(args)):
        args[i] = '^' + args[i]
    revtree(args, repo, full, doptions['max-nr'])

def catchterm(*args):
    raise SignalInterrupt

def help():
    sys.stderr.write("commands:\n")
    sys.stderr.write("  hgit cat-file [type] sha1\n")
    sys.stderr.write("  hgit diff-tree [-p] [-r] sha1 sha1\n")
    sys.stderr.write("  hgit rev-tree [sha1 ... [^stop sha1]]\n")
    sys.stderr.write("  hgit rev-list [-c] [sha1 [stop sha1]\n")

cmd = sys.argv[1]
args = sys.argv[2:]
u = ui.ui()
signal.signal(signal.SIGTERM, catchterm)
repo = hg.repository(ui = u)

if cmd == "diff-tree":
    difftree(args, u, repo)

elif cmd == "cat-file":
    catfile(args, u, repo)

elif cmd == "rev-tree":
    revtree(args, repo)

elif cmd == "rev-list":
    revlist(args, repo)

elif cmd == "help":
    help()

else:
    if cmd: sys.stderr.write("unknown command\n\n")
    help()
    sys.exit(1)

sys.exit(0)