#!/usr/bin/python

# Copyright (c) 2013, Yeukhon Wong <yeukhon@acm.org>
# Copyright (c) 2014, Nate Coraor <nate@bx.psu.edu>
# GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
# SPDX-License-Identifier: GPL-3.0-or-later

from __future__ import annotations

DOCUMENTATION = r"""
module: hg
short_description: Manages Mercurial (hg) repositories
description:
  - Manages Mercurial (hg) repositories. Supports SSH, HTTP/S and local address.
author: "Yeukhon Wong (@yeukhon)"
extends_documentation_fragment:
  - community.general._attributes
attributes:
  check_mode:
    support: none
  diff_mode:
    support: none
options:
  repo:
    description:
      - The repository address.
    required: true
    aliases: [name]
    type: str
  dest:
    description:
      - Absolute path of where the repository should be cloned to. This parameter is required, unless clone and update are
        set to no.
    type: path
  revision:
    description:
      - Equivalent C(-r) option in hg command which could be the changeset, revision number, branch name or even tag.
    aliases: [version]
    type: str
  force:
    description:
      - Discards uncommitted changes. Runs C(hg update -C).
    type: bool
    default: false
  purge:
    description:
      - Deletes untracked files. Runs C(hg purge).
    type: bool
    default: false
  update:
    description:
      - If V(false), do not retrieve new revisions from the origin repository.
    type: bool
    default: true
  clone:
    description:
      - If V(false), do not clone the repository if it does not exist locally.
    type: bool
    default: true
  executable:
    description:
      - Path to C(hg) executable to use. If not supplied, the normal mechanism for resolving binary paths is used.
    type: str
notes:
  - This module does not support push capability. See U(https://github.com/ansible/ansible/issues/31156).
  - 'If the task seems to be hanging, first verify remote host is in C(known_hosts). SSH prompts user to authorize the first
    contact with a remote host. To avoid this prompt, one solution is to add the remote host public key in C(/etc/ssh/ssh_known_hosts)
    before calling the hg module, with the following command: C(ssh-keyscan remote_host.com >> /etc/ssh/ssh_known_hosts).'
  - As per 01 Dec 2018, Bitbucket has dropped support for TLSv1 and TLSv1.1 connections. As such, if the underlying system
    still uses a Python version below 2.7.9, you are bound to have issues checking out bitbucket repositories. See
    U(https://bitbucket.org/blog/deprecating-tlsv1-tlsv1-1-2018-12-01).
"""

EXAMPLES = r"""
- name: Ensure the current working copy is inside the stable branch and deletes untracked files if any.
  community.general.hg:
    repo: https://bitbucket.org/user/repo1
    dest: /home/user/repo1
    revision: stable
    purge: true

- name: Get information about the repository whether or not it has already been cloned locally.
  community.general.hg:
    repo: git://bitbucket.org/user/repo
    dest: /srv/checkout
    clone: false
    update: false
"""

import os

from ansible.module_utils.basic import AnsibleModule


class Hg:
    def __init__(self, module, dest, repo, revision, hg_path):
        self.module = module
        self.dest = dest
        self.repo = repo
        self.revision = revision
        self.hg_path = hg_path

    def _command(self, args_list):
        (rc, out, err) = self.module.run_command([self.hg_path] + args_list)
        return (rc, out, err)

    def _list_untracked(self):
        args = ["purge", "--config", "extensions.purge=", "-R", self.dest, "--print"]
        return self._command(args)

    def get_revision(self):
        """
        hg id -b -i -t returns a string in the format:
           "<changeset>[+] <branch_name> <tag>"
        This format lists the state of the current working copy,
        and indicates whether there are uncommitted changes by the
        plus sign. Otherwise, the sign is omitted.

        Read the full description via hg id --help
        """
        (rc, out, err) = self._command(["id", "-b", "-i", "-t", "-R", self.dest])
        if rc != 0:
            self.module.fail_json(msg=err)
        else:
            return out.strip("\n")

    def get_remote_revision(self):
        (rc, out, err) = self._command(["id", self.repo])
        if rc != 0:
            self.module.fail_json(msg=err)
        else:
            return out.strip("\n")

    def has_local_mods(self):
        now = self.get_revision()
        return "+" in now

    def discard(self):
        before = self.has_local_mods()
        if not before:
            return False

        args = ["update", "-C", "-R", self.dest, "-r", "."]
        (rc, out, err) = self._command(args)
        if rc != 0:
            self.module.fail_json(msg=err)

        after = self.has_local_mods()
        if before != after and not after:  # no more local modification
            return True

    def purge(self):
        # before purge, find out if there are any untracked files
        (rc1, out1, err1) = self._list_untracked()
        if rc1 != 0:
            self.module.fail_json(msg=err1)

        # there are some untrackd files
        if out1 != "":
            args = ["purge", "--config", "extensions.purge=", "-R", self.dest]
            (rc2, out2, err2) = self._command(args)
            if rc2 != 0:
                self.module.fail_json(msg=err2)
            return True
        else:
            return False

    def cleanup(self, force, purge):
        discarded = False
        purged = False

        if force:
            discarded = self.discard()
        if purge:
            purged = self.purge()
        return discarded or purged

    def pull(self):
        return self._command(["pull", "-R", self.dest, self.repo])

    def update(self):
        if self.revision is not None:
            return self._command(["update", "-r", self.revision, "-R", self.dest])
        return self._command(["update", "-R", self.dest])

    def clone(self):
        if self.revision is not None:
            return self._command(["clone", self.repo, self.dest, "-r", self.revision])
        return self._command(["clone", self.repo, self.dest])

    @property
    def at_revision(self):
        """
        There is no point in pulling from a potentially down/slow remote site
        if the desired changeset is already the current changeset.
        """
        if self.revision is None or len(self.revision) < 7:
            # Assume it is a rev number, tag, or branch
            return False
        (rc, out, err) = self._command(["--debug", "id", "-i", "-R", self.dest])
        if rc != 0:
            self.module.fail_json(msg=err)
        return out.startswith(self.revision)


# ===========================================


def main():
    module = AnsibleModule(
        argument_spec=dict(
            repo=dict(type="str", required=True, aliases=["name"]),
            dest=dict(type="path"),
            revision=dict(type="str", aliases=["version"]),
            force=dict(type="bool", default=False),
            purge=dict(type="bool", default=False),
            update=dict(type="bool", default=True),
            clone=dict(type="bool", default=True),
            executable=dict(type="str"),
        ),
    )
    module.run_command_environ_update = {"LANGUAGE": "C", "LC_ALL": "C"}
    repo = module.params["repo"]
    dest = module.params["dest"]
    revision = module.params["revision"]
    force = module.params["force"]
    purge = module.params["purge"]
    update = module.params["update"]
    clone = module.params["clone"]
    hg_path = module.params["executable"] or module.get_bin_path("hg", True)
    if dest is not None:
        hgrc = os.path.join(dest, ".hg/hgrc")

    # initial states
    before = ""
    changed = False
    cleaned = False

    if not dest and (clone or update):
        module.fail_json(msg="the destination directory must be specified unless clone=false and update=false")

    hg = Hg(module, dest, repo, revision, hg_path)

    # If there is no hgrc file, then assume repo is absent
    # and perform clone. Otherwise, perform pull and update.
    if not clone and not update:
        out = hg.get_remote_revision()
        module.exit_json(after=out, changed=False)
    if not os.path.exists(hgrc):
        if clone:
            (rc, out, err) = hg.clone()
            if rc != 0:
                module.fail_json(msg=err)
        else:
            module.exit_json(changed=False)
    elif not update:
        # Just return having found a repo already in the dest path
        before = hg.get_revision()
    elif hg.at_revision:
        # no update needed, don't pull
        before = hg.get_revision()

        # but force and purge if desired
        cleaned = hg.cleanup(force, purge)
    else:
        # get the current state before doing pulling
        before = hg.get_revision()

        # can perform force and purge
        cleaned = hg.cleanup(force, purge)

        (rc, out, err) = hg.pull()
        if rc != 0:
            module.fail_json(msg=err)

        (rc, out, err) = hg.update()
        if rc != 0:
            module.fail_json(msg=err)

    after = hg.get_revision()
    if before != after or cleaned:
        changed = True

    module.exit_json(before=before, after=after, changed=changed, cleaned=cleaned)


if __name__ == "__main__":
    main()
