# -*- coding: utf-8 -*-

from ansible.module_utils.basic import AnsibleModule
import git
import itertools
import multiprocessing
import os
import signal
import time

DOCUMENTATION = """
---
module: git_requirements
short_description: Module to run a multithreaded git clone

options:
  repo_info:
    description:
      - List of repo information dictionaries containing at
        a minimum a key entry "src" with the source git URL
        to clone for each repo. In these dictionaries, one
        can further specify:
        "path" - destination clone location
        "version" - git version to checkout
        "refspec" - git refspec to checkout
        "depth" - clone depth level
        "shallow_since" - get repo history starting from that date
        "force" - require git clone uses "--force"
  default_path:
    description:
      Default git clone path (str) in case not
      specified on an individual repo basis in
      repo_info. Defaults to "master". Not
      required.
  default_version:
    description:
      Default git version (str) in case not
      specified on an individual repo basis in
      repo_info. Defaults to "master". Not
      required.
  default_refspec:
    description:
      Default git repo refspec (str) in case not
      specified on an individual repo basis in
      repo_info. Defaults to "". Not required.
  default_depth:
    description:
      Default clone depth (int) in case not specified
      on an individual repo basis. Defaults to None.
      Not required.
  default_shallow_since:
    description:
      Default shallow date (str) strating from which
      git history will be fetched. Defaults to None.
      Has prescedence over depth.
      Not required.
  retries:
     description:
      Integer number of retries allowed in case of git
      clone failure. Defaults to 1. Not required.
  delay:
    description:
      Integer time delay (seconds) between git clone
      retries in case of failure. Defaults to 0. Not
      required.
  force:
    description:
      Boolean. Apply --force flags to git clones wherever
      possible. Defaults to False. Not required.
  core_multiplier:
    description:
      Integer multiplier on the number of cores
      present on the machine to use for
      multithreading. For example, on a 2 core
      machine, a multiplier of 4 would use 8
      threads. Defaults to 4. Not required.
  core_maximum:
    description:
      Integer maximum number of cores that should be
      used for multithreading. Use of too many cores
      simultaneously will cause file decscriptors
      to be exhausted. Defaults to 16. Not required.
"""

EXAMPLES = r"""

- name: Clone repos
  git_requirements:
    repo_info: "[{'src':'https://github.com/ansible/',
                  'name': 'ansible'
                  'dest': '/etc/opt/ansible'}]"
"""


def init_signal():
    signal.signal(signal.SIGINT, signal.SIG_IGN)


def check_out_version(repo, version, pull=False, fetch=True, force=False,
                      refspec=None, tag=False, depth=None,
                      shallow_since=None):
    if fetch:
        try:
            if shallow_since:
                depth = None
            repo.git.fetch(tags=tag, force=force, refspec=refspec,
                           depth=depth, shallow_since=shallow_since)
        except Exception as e:
            return ["Failed to fetch %s\n%s" % (repo.working_dir, str(e))]

    try:
        repo.git.checkout(version, force=force)
    except Exception as e:
        return [
            "Failed to check out version %s for %s\n%s" %
            (version, repo.working_dir, str(e))]

    if repo.is_dirty(untracked_files=True) and force:
        try:
            repo.git.clean(force=force)
        except Exception as e:
            return [
                "Failed to clean up repository% s\n%s" %
                (repo.working_dir, str(e))]

    if pull:
        try:
            repo.git.pull(force=force, refspec=refspec, depth=depth)
        except Exception as e:
            return ["Failed to pull repo %s\n%s" % (repo.working_dir, str(e))]
    return []


def pull_wrapper(info):
    role_info = info
    retries = info[1]["retries"]
    delay = info[1]["delay"]
    for i in range(retries):
        success = pull_role(role_info)
        if success:
            return True
        else:
            time.sleep(delay)
    info[2].append(["Role {0} failed after {1} retries\n".format(role_info[0],
                                                                 retries)])
    return False


def pull_role(info):
    role, config, failures = info

    required_version = role["version"]
    version_hash = False
    if 'version' in role:
        # If the version is the length of a hash then treat is as one
        if len(required_version) == 40:
            version_hash = True

    def get_repo(dest):
        try:
            return git.Repo(dest)
        except Exception:
            failtxt = "Role in {0} is broken/not a git repo.".format(
                role["dest"])
            failtxt += "Please delete or fix it manually"
            failures.append(failtxt)
            return False

    # if repo exists
    if os.path.exists(role["dest"]):
        repo = get_repo(role["dest"])
        if not repo:
            return False  # go to next role
        repo_url = list(repo.remote().urls)[0]
        if repo_url != role["src"]:
            repo.remote().set_url(role["src"])

        # if they want master then fetch, checkout and pull to stay at latest
        # master
        if required_version == "master":
            fail = check_out_version(repo, required_version, pull=True,
                                     force=config["force"],
                                     refspec=role["refspec"],
                                     depth=role["depth"],
                                     shallow_since=role["shallow_since"])

        # If we have a hash then reset it to
        elif version_hash:
            fail = check_out_version(repo, required_version,
                                     force=config["force"],
                                     refspec=role["refspec"],
                                     depth=role["depth"],
                                     shallow_since=role["shallow_since"])
        else:
            # describe can fail in some cases so be careful:
            try:
                current_version = repo.git.describe(tags=True)
            except Exception:
                current_version = ""
            if current_version == required_version and not config["force"]:
                fail = []
                pass
            else:
                fail = check_out_version(repo, required_version,
                                         force=config["force"],
                                         refspec=role["refspec"],
                                         depth=role["depth"],
                                         shallow_since=role["shallow_since"],
                                         tag=True)

    else:
        try:
            # If we have a hash id then treat this a little differently
            shallow_since = role.get('shallow_since')
            if shallow_since:
                depth = None
            else:
                depth = role.get('depth')

            if version_hash:
                repo = git.Repo.clone_from(role["src"], role["dest"],
                                           no_single_branch=True,
                                           depth=depth,
                                           shallow_since=shallow_since,)
                if not repo:
                    return False  # go to next role
                fail = check_out_version(repo, required_version,
                                         force=config["force"],
                                         refspec=role["refspec"],
                                         depth=depth,
                                         fetch=False,
                                         shallow_since=shallow_since,)
            else:
                git.Repo.clone_from(role["src"], role["dest"],
                                    branch=required_version,
                                    depth=depth,
                                    shallow_since=shallow_since,
                                    no_single_branch=True)
                fail = []

        except Exception as e:
            fail = ('Failed cloning repo %s\n%s' % (role["dest"], str(e)))

    if fail == []:
        return True
    else:
        failures.append(fail)
        return False


def set_default(dictionary, key, defaults):
    if key not in dictionary.keys():
        dictionary[key] = defaults[key]


def main():
    # Define variables
    failures = multiprocessing.Manager().list()

    # Data we can pass in to the module
    fields = {
        "repo_info": {"required": True, "type": "list"},
        "default_path": {"required": True,
                         "type": "str"},
        "default_version": {"required": False,
                            "type": "str",
                            "default": "master"},
        "default_refspec": {"required": False,
                            "type": "str",
                            "default": None},
        "default_depth": {"required": False,
                          "type": "int",
                          "default": None},
        "default_shallow_since": {"required": False,
                                  "type": str,
                                  "default": None},
        "retries": {"required": False,
                    "type": "int",
                    "default": 1},
        "delay": {"required": False,
                  "type": "int",
                  "default": 0},
        "force": {"required": False,
                  "type": "bool",
                  "default": False},
        "core_multiplier": {"required": False,
                            "type": "int",
                            "default": 4},
        "core_maximum": {"required": False,
                          "type": "int",
                          "default": 16},
    }

    # Pull in module fields and pass into variables
    module = AnsibleModule(argument_spec=fields)

    git_repos = module.params['repo_info']
    defaults = {
        "path": module.params["default_path"],
        "depth": module.params["default_depth"],
        "shallow_since": module.params["default_shallow_since"],
        "version": module.params["default_version"],
        "refspec": module.params["default_refspec"]
    }
    config = {
        "retries": module.params["retries"],
        "delay": module.params["delay"],
        "force": module.params["force"],
        "core_multiplier": module.params["core_multiplier"],
        "core_maximum": module.params["core_maximum"]
    }

    # Set up defaults
    for repo in git_repos:
        for key in ["path", "refspec", "version", "depth", "shallow_since"]:
            set_default(repo, key, defaults)
        if "name" not in repo.keys():
            repo["name"] = os.path.basename(repo["src"])
        repo["dest"] = os.path.join(repo["path"], repo["name"])

    # Define varibles
    failures = multiprocessing.Manager().list()
    core_count = multiprocessing.cpu_count() * config["core_multiplier"]
    core_count = min(core_count, config["core_maximum"])

    # Load up process and pass in interrupt and core process count
    p = multiprocessing.Pool(core_count, init_signal)

    clone_success = p.map(pull_wrapper, zip(git_repos,
                                            itertools.repeat(config),
                                            itertools.repeat(failures)),
                          chunksize=1)
    p.close()

    success = all(i for i in clone_success)
    if success:
        module.exit_json(msg=str(git_repos), changed=True)
    else:
        module.fail_json(msg=("Module failed"), meta=failures)


if __name__ == '__main__':
    main()