from mr.developer import common
import os
import subprocess


logger = common.logger


class DarcsError(common.WCError):
    pass


class DarcsWorkingCopy(common.BaseWorkingCopy):

    def __init__(self, source):
        super(DarcsWorkingCopy, self).__init__(source)
        self.darcs_executable = common.which('darcs')

    def darcs_checkout(self, **kwargs):
        name = self.source['name']
        path = self.source['path']
        url = self.source['url']
        if os.path.exists(path):
            self.output((logger.info, "Skipped getting of existing package '%s'." % name))
            return
        self.output((logger.info, "Getting '%s' with darcs." % name))
        cmd = [self.darcs_executable, "get", "--quiet", "--lazy", url, path]
        cmd = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        stdout, stderr = cmd.communicate()
        if cmd.returncode != 0:
            raise DarcsError("darcs get for '%s' failed.\n%s" % (name, stderr))
        if kwargs.get('verbose', False):
            return stdout

    def darcs_update(self, **kwargs):
        name = self.source['name']
        path = self.source['path']
        self.output((logger.info, "Updating '%s' with darcs." % name))
        cmd = subprocess.Popen([self.darcs_executable, "pull", "-a"],
                               cwd=path,
                               stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE)
        stdout, stderr = cmd.communicate()
        if cmd.returncode != 0:
            raise DarcsError("darcs pull for '%s' failed.\n%s" % (name, stderr))
        if kwargs.get('verbose', False):
            return stdout

    def checkout(self, **kwargs):
        name = self.source['name']
        path = self.source['path']
        update = self.should_update(**kwargs)
        if os.path.exists(path):
            if update:
                self.update(**kwargs)
            elif self.matches():
                self.output((logger.info, "Skipped checkout of existing package '%s'." % name))
            else:
                raise DarcsError("Checkout URL for existing package '%s' differs. Expected '%s'." % (name, self.source['url']))
        else:
            return self.darcs_checkout(**kwargs)

    def _darcs_related_repositories(self):
        name = self.source['name']
        path = self.source['path']
        repos = os.path.join(path, '_darcs', 'prefs', 'repos')
        if os.path.exists(repos):
            for line in open(repos).readlines():
                yield line.strip()
        else:
            cmd = subprocess.Popen([self.darcs_executable, "show", "repo"],
                                   cwd=path,
                                   stdout=subprocess.PIPE,
                                   stderr=subprocess.PIPE)
            stdout, stderr = cmd.communicate()
            if cmd.returncode != 0:
                self.output((logger.error, "darcs info for '%s' failed.\n%s" % (name, stderr)))
                return

            lines = stdout.splitlines()
            for line in lines:
                k, v = line.split(':', 1)
                k = k.strip()
                v = v.strip()
                if k == 'Default Remote':
                    yield v
                elif k == 'Cache':
                    for cache in v.split(', '):
                        if cache.startswith('repo:'):
                            yield cache[5:]

    def matches(self):
        return self.source['url'] in self._darcs_related_repositories()

    def status(self, **kwargs):
        path = self.source['path']
        cmd = subprocess.Popen([self.darcs_executable, "whatsnew"],
                               cwd=path,
                               stdout=subprocess.PIPE,
                               stderr=subprocess.PIPE)
        stdout, stderr = cmd.communicate()
        lines = stdout.strip().split('\n')
        if 'No changes' in lines[-1]:
            status = 'clean'
        else:
            status = 'dirty'
        if kwargs.get('verbose', False):
            return status, stdout
        else:
            return status

    def update(self, **kwargs):
        name = self.source['name']
        if not self.matches():
            raise DarcsError("Can't update package '%s' because it's URL doesn't match." % name)
        if self.status() != 'clean' and not kwargs.get('force', False):
            raise DarcsError("Can't update package '%s' because it's dirty." % name)
        return self.darcs_update(**kwargs)