import os
import re
from subprocess import Popen, PIPE, STDOUT

from method import Method, Argument
from method.vc import VcBlame

try:
    from mercurial import hg, ui, node
    from mercurial import commands as hgc
    has_hg = True
except ImportError:
    has_hg = False

class HgBase(object):
    def _hg_check(self, w):
        if not has_hg:
            w.set_error("Mercurial is not installed")
            return False
        elif not hasattr(w.buffer, 'path'):
            w.set_error("Buffer has no corresponding file")
            return False
        else:
            return True
    def _hg_init(self, **kwargs):
        ui_imp = ui.ui(**kwargs)
        ui_imp.pushbuffer()
        repo = hg.repository(ui=ui_imp, path='.')
        return ui_imp, repo

class HgBlame(VcBlame, HgBase):
    """Show buffer annotated with hg metadata"""
    num_fields = 3
    # user, rev, [changeset], date, content
    line_re    = re.compile(r'^ *([^ ]+) +(\d+) +[^ ]+ +(\d{4}-\d{2}-\d{2}): (.*)\n$')
    prefix_fmt = '[g:d:*]%*s [c:d:*]%*s [b:d:*]%*s[d:d:*]'
    _is_method = True
    def _open_pipe(self, w, **vargs):
        cmd = ("hg", 'blame', '-cnudq', w.buffer.path)
        return Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)

class HgLog(Method, HgBase):
    """Show hg log for this buffer"""
    def _execute(self, w, **vargs):
        if not self._hg_check(w):
            return
        ui_imp, repo = self._hg_init()
        hgc.log(ui_imp, repo, user=None, rev=None, date=None)
        s = ''.join(ui_imp.popbuffer())
        w.application.data_buffer('*Log*', s, switch_to=True)

class HgInfo(Method, HgBase):
    """Get some basic info from Mercurial about the current buffer"""
    def _execute(self, w, **vargs):
        if not self._hg_check(w):
            return
        base = os.path.basename(w.buffer.path)
        ui_imp, repo = self._hg_init()
        path = w.buffer.path.replace(os.getcwd() + '/', '')
        l = repo.file(path)
        status = 'Unknown'
        rev = l.linkrev(l.rev(l.tip()))
        ctx = repo[rev]
        changeid = node.hex(ctx.node()[:6])
        user = ui_imp.shortuser(ctx.user())
        msg = '%s  %s  %s:%s  [%s]' % (base, status, rev, changeid, user)
        w.set_error(msg)

class HgDiff(Method, HgBase):
    """Diff the current file with the version in Mercurial"""
    def _get_revs(self, w, **vargs):
        return []
    def _execute(self, w, **vargs):
        if not self._hg_check(w):
            return
        ui_imp, repo = self._hg_init()
        revs = self._get_revs(w, **vargs)
        try:
            c = w.application.config
            opts = {
                'ignore_all_space':    c.get('hg.diff.ignore_app_space'),
                'ignore_space_change': c.get('hg.diff.ignore_space_change'),
                'ignore-blank-lines':  c.get('hg.diff.ignore_blank_lines'),
                'unified':             c.get('hg.diff.unified'),
            }
            hgc.diff(ui_imp, repo, w.buffer.path, rev=revs, **opts)
        except Exception as e:
            w.set_error(str(e))
            return
        s = ''.join(ui_imp.popbuffer())
        w.application.data_buffer("*Diff*", s, switch_to=True, modename='diff')

class HgDiff2(HgDiff):
    """Diff the current file with a specific revision in Mercurial"""
    args = [Argument("revision", type=type(""), prompt="Revision: ")]
    def _get_revs(self, w, **vargs):
        return [vargs['revision']]

class HgDiff3(HgDiff):
    """Diff the current file with a specific revision in Mercurial"""
    args = [Argument("revision1", type=type(""), prompt="First Revision: "),
            Argument("revision2", type=type(""), prompt="Second Revision: ")]
    def _get_revs(self, w, **vargs):
        return [vargs['revision1'], vargs['revision2']]