#!/usr/bin/env python3

# This file is part of Cockpit.
#
# Copyright (C) 2017 Red Hat, Inc.
#
# Cockpit is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# Cockpit is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with Cockpit; If not, see <http://www.gnu.org/licenses/>.

# Shared GitHub code. When run as a script, we print out info about
# our GitHub interacition.

import argparse
import os
import random
import shutil
import socket
import subprocess
import sys
import time
import traceback
import urllib.parse

sys.dont_write_bytecode = True

from . import github
from . import sink

__all__ = (
    "api",
    "main",
    "run",
    "pull",
    "comment",
    "label",
    "issue",
    "verbose",
    "stale",
    "redhat_network",
    "REDHAT_STORE",
)

# Server which has the private RHEL/Windows images
REDHAT_STORE = "https://cockpit-11.e2e.bos.redhat.com:8493"

api = github.GitHub()
verbose = False

BOTS = os.path.normpath(os.path.join(os.path.dirname(__file__), ".."))
BASE = os.path.normpath(os.path.join(BOTS, ".."))

#
# The main function takes a list of tasks, each of wihch has the following
# fields, some of which have defaults:
#
#   title: The title for the task
#   function: The function to call for the task
#   options=[]: A list of string options to pass to the function argument
#
# The function for the task will be called with all the context for the task.
# In addition it will be called with named arguments for all other task fields
# and additional fields such as |verbose|. It should return a zero or None value
# if successful, and a string or non-zero value if unsuccessful.
#
#   def run(context, verbose=False, **kwargs):
#       if verbose:
#           sys.stderr.write(image + "\n")
#       return 0
#
# Call the task.main() as the entry point of your script in one of these ways:
#
#   # As a single task
#   task.main(title="My title", function=run)
#

def main(**kwargs):
    global verbose

    task = kwargs.copy()

    # Figure out a descriptoin for the --help
    task["name"] = named(task)

    parser = argparse.ArgumentParser(description=task.get("title", task["name"]))
    parser.add_argument("-v", "--verbose", action="store_true", help="Verbose output")
    parser.add_argument("--issue", dest="issue", action="store",
        help="Act on an already created task issue")
    parser.add_argument("--publish", dest="publish", default=os.environ.get("TEST_PUBLISH", ""),
        action="store", help="Publish results centrally to a sink")
    parser.add_argument("--dry", dest="dry", action="store_true",
        help="Dry run to validate this task if supported")
    parser.add_argument("context", nargs="?")

    opts = parser.parse_args()
    verbose = opts.verbose

    ret = 0

    if "verbose" not in task:
        task["verbose"] = opts.verbose
    task["issue"] = opts.issue
    task["publish"] = opts.publish
    task["dry"] = opts.dry

    ret = run(opts.context, **task)

    if ret:
        sys.stderr.write("{0}: {1}\n".format(task["name"], ret))

    sys.exit(ret and 1 or 0)

def named(task):
    if "name" in task:
        return task["name"]
    else:
        return os.path.basename(os.path.realpath(sys.argv[0]))

def begin(publish, name, context, issue):
    if not publish:
        return None

    hostname = socket.gethostname().split(".")[0]
    current = time.strftime('%Y%m%d-%H%M%M')

    # Update the body for an existing issue
    if issue:
        number = issue["number"]
        identifier = "{0}-{1}-{2}".format(name, number, current)
        title = issue["title"]
        wip = "WIP: {0}: [no-test] {1}".format(hostname, title)
        requests = [ {
            "method": "POST",
            "resource": api.qualify("issues/{0}".format(number)),
            "data": { "title": wip }
        }, {
            "method": "POST",
            "resource": api.qualify("issues/{0}/comments".format(number)),
            "data": { "body": "{0} in progress on {1}.\nLog: :link".format(name, hostname) }
        } ]
        watches = [ {
            "resource": api.qualify("issues/{0}".format(number)),
            "result": { "title": wip }
        } ]
        aborted = [ {
            "method": "POST",
            "resource": api.qualify("issues/{0}".format(number)),
            "data": { "title": title }
        }, {
            "method": "POST",
            "resource": api.qualify("issues/{0}/comments".format(number)),
            "data": { "body": "Task aborted." }
        } ]
    else:
        identifier = "{0}-{1}".format(name, current)
        requests = [ ]
        watches = [ ]
        aborted = [ ]

    status = {
        "github": {
            "token": api.token,
            "requests": requests,
            "watches": watches
        },

        "onaborted": {
            "github": {
                "token": api.token,
                "requests": aborted
            }
        }
    }

    publishing = sink.Sink(publish, identifier, status)
    sys.stderr.write("# Task: {0} {1}\n# Host: {2}\n\n".format(name, context or "", hostname))

    # For statistics
    publishing.start = time.time()

    return publishing

def finish(publishing, ret, name, context, issue):
    if not publishing:
        return

    if not ret:
        comment = None
        result = "Completed"
    elif isinstance(ret, str):
        comment = "{0}: :link".format(ret)
        result = ret
    else:
        comment = "Task failed: :link"
        result = "Failed"

    duration = int(time.time() - publishing.start)
    sys.stderr.write("\n# Result: {0}\n# Duration: {1}s\n".format(result, duration))

    if issue:
        # Note that we check whether pass or fail ... this is because
        # the task is considered "done" until a human comes through and
        # triggers it again by unchecking the box.
        item = "{0} {1}".format(name, context or "").strip()
        checklist = github.Checklist(issue["body"])
        checklist.check(item, ret and "FAIL" or True)

        number = issue["number"]

        # The sink wants us to escape colons :S
        body = checklist.body.replace(':', '::')

        requests = [ {
            "method": "POST",
            "resource": api.qualify("issues/{0}".format(number)),
            "data": { "title": "{0}".format(issue["title"]), "body": body }
        } ]

        # Close the issue if it's not a pull request, successful, and all tasks done
        if "pull_request" not in issue and not ret and len(checklist.items) == len(checklist.checked()):
            requests[0]["data"]["state"] = "closed"

        # Comment if there was a failure
        if comment:
            requests.insert(0, {
                "method": "POST",
                "resource": api.qualify("issues/{0}/comments".format(number)),
                "data": { "body": comment }
            })

    else:
        requests = [ ]

    publishing.status['github']['requests'] = requests
    publishing.status['github']['watches'] = None
    publishing.status['github']['onaborted'] = None
    publishing.flush()

def run(context, function, **kwargs):
    number = kwargs.get("issue", None)
    publish = kwargs.get("publish", "")
    name = kwargs["name"]

    issue = None
    if number:
        issue = api.get("issues/{0}".format(number))
        if not issue:
            return "No such issue: {0}".format(number)
        elif issue["title"].startswith("WIP:"):
            return "Issue is work in progress: {0}: {1}\n".format(number, issue["title"])
        kwargs["issue"] = issue
        kwargs["title"] = issue["title"]

    publishing = begin(publish, name, context, issue=issue)

    ret = "Task threw an exception"
    try:
        if issue and "pull_request" in issue:
           kwargs["pull"] = api.get(issue["pull_request"]["url"])

        ret = function(context, **kwargs)
    except (RuntimeError, subprocess.CalledProcessError) as ex:
        ret = str(ex)
    except (AssertionError, KeyboardInterrupt):
        raise
    except:
        traceback.print_exc()
    finally:
        finish(publishing, ret, name, context, issue)
    return ret or 0

# Check if the given files that match @pathspec are stale
# and haven't been updated in @days.
def stale(days, pathspec, ref="HEAD"):
    global verbose

    def execute(*args):
        if verbose:
            sys.stderr.write("+ " + " ".join(args) + "\n")
        output = subprocess.check_output(args, cwd=BASE, universal_newlines=True)
        if verbose:
            sys.stderr.write("> " + output + "\n")
        return output

    timestamp = execute("git", "log", "--max-count=1", "--pretty=format:%ct", ref, "--", pathspec)
    try:
        timestamp = int(timestamp)
    except ValueError:
        timestamp = 0

    # We randomize when we think this should happen over a day
    offset = days * 86400
    due = time.time() - random.randint(offset - 43200, offset + 43200)

    return timestamp < due

def issue(title, body, item, context=None, items=[], state="open", since=None):
    if context:
        item = "{0} {1}".format(item, context).strip()

    if since:
        # don't let all bots pass the deadline in the same second, to avoid many duplicates
        since += random.randint(-3600, 3600)

    for issue in api.issues(state=state, since=since):
        checklist = github.Checklist(issue["body"])
        if item in checklist.items:
            return issue

    if not items:
        items = [ item ]
    checklist = github.Checklist(body)
    for x in items:
        checklist.add(x)
    data = {
        "title": title,
        "body": checklist.body,
        "labels": [ "bot" ]
    }
    return api.post("issues", data)

def execute(*args):
    global verbose
    if verbose:
        sys.stderr.write("+ " + " ".join(args) + "\n")

    # Make double sure that the token does not appear anywhere in the output
    def censored(text):
        return text.replace(api.token, "CENSORED")

    env = os.environ.copy()
    # No prompting for passwords
    if "GIT_ASKPASS" not in env:
        env["GIT_ASKPASS"] = "/bin/true"
    output = subprocess.check_output(args, cwd=BASE, stderr=subprocess.STDOUT, env=env, universal_newlines=True)
    sys.stderr.write(censored(output))
    return output

def find_our_fork(user):
    repos = api.get("/users/{0}/repos".format(user))
    for r in repos:
        if r["full_name"] == api.repo:
            # We actually own the origin repo, so use that.
            return api.repo
        if r["fork"]:
            full = api.get("/repos/{0}/{1}".format(user, r["name"]))
            if full["parent"]["full_name"] == api.repo:
                return full["full_name"]
    raise RuntimeError("%s doesn't have a fork of %s" % (user, api.repo))

def push_branch(user, branch, force=False):
    fork_repo = find_our_fork(user)

    url = "https://github.com/{0}".format(fork_repo)
    cmd = ["git", "push", url, "+HEAD:refs/heads/{0}".format(branch)]
    if force:
        cmd.insert(2, "-f")
    execute(*cmd)

def branch(context, message, pathspec=".", issue=None, branch=None, push=True, **kwargs):
    name = named(kwargs)
    if not branch:
        execute("git", "checkout", "--detach")
        current = time.strftime('%Y%m%d-%H%M%M')
        branch = "{0} {1} {2}".format(name, context or "", current).strip()
        branch = branch.replace(" ", "-").replace("--", "-")

    # Tell git about our github token as a user name
    try:
        subprocess.check_call(["git", "config", "credential.https://github.com.username", api.token])
    except subprocess.CalledProcessError:
        raise RuntimeError("Couldn't configure git config with our API token")

    user = api.get("/user")['login']
    fork_repo = find_our_fork(user)

    clean = "https://github.com/{0}".format(fork_repo)

    if pathspec is not None:
        execute("git", "add", "--", pathspec)

    # If there's nothing to add at that pathspec return None
    try:
        execute("git", "commit", "-m", message)
    except subprocess.CalledProcessError:
        return None

    # No need to push if we want to add another commits into the same branch
    if push:
        push_branch(user, branch)

    # Comment on the issue if present and we pushed the branch
    if issue and push:
        comment_done(issue, name, clean, branch, context)

    return "{0}:{1}".format(user, branch)

def pull(branch, body=None, issue=None, base="master", labels=['bot'], run_tests=True, **kwargs):
    if "pull" in kwargs:
        return kwargs["pull"]

    data = {
        "head": branch,
        "base": base,
        "maintainer_can_modify": True
    }
    if issue:
        try:
            data["issue"] = issue["number"]
        except TypeError:
            data["issue"] = int(issue)
    else:
        data["title"] = "[no-test] " + kwargs["title"]
        if body:
            data["body"] = body

    pull = api.post("pulls", data, accept=[ 422 ])

    # If we were refused to grant maintainer_can_modify, then try without
    if "errors" in pull:
        if pull["errors"][0]["field"] == "fork_collab":
            data["maintainer_can_modify"] = False
        pull = api.post("pulls", data)

    # Update the pull request
    label(pull, labels)

    # Update the issue if it is a dict
    if issue:
        try:
            issue["title"] = kwargs["title"]
            issue["pull_request"] = { "url": pull["url"] }
        except TypeError:
            pass

    if pull["number"]:
        # If we want to run tests automatically, drop [no-test] from title before force push
        if run_tests:
            pull = api.post("pulls/" + str(pull["number"]), {"title": kwargs["title"]}, accept=[ 422 ])

        # Force push
        last_commit_m = execute("git", "show", "--no-patch", "--format=%B")
        last_commit_m += "Closes #" + str(pull["number"])
        execute("git", "commit", "--amend", "-m", last_commit_m)
        (user, branch) = branch.split(":")
        push_branch(user, branch, True)

        # Make sure we return the updated pull data
        for retry in range(20):
            new_data = api.get("pulls/{}".format(pull["number"]))
            if pull["head"]["sha"] != new_data["head"]["sha"]:
                pull = new_data
                break
            time.sleep(6)
        else:
            raise RuntimeError("Failed to retrieve updated pull data after force pushing")

    return pull

def label(issue, labels=['bot']):
    try:
        resource = "issues/{0}/labels".format(issue["number"])
    except TypeError:
        resource = "issues/{0}/labels".format(issue)
    return api.post(resource, labels)

def labels_of_pull(pull):
    if "labels" not in pull:
        pull["labels"] = api.get("issues/{0}/labels".format(pull["number"]))
    return list(map(lambda label: label["name"], pull["labels"]))

def comment(issue, comment):
    try:
        number = issue["number"]
    except TypeError:
        number = issue
    return api.post("issues/{0}/comments".format(number), { "body": comment })

def comment_done(issue, name, clean, branch, context=None):
    message = "{0} {1} done: {2}/commits/{3}".format(name, context or "", clean, branch)
    comment(issue, message)

def attach(filename):
    if "TEST_ATTACHMENTS" in os.environ:
        shutil.copy(filename, os.environ["TEST_ATTACHMENTS"])

def redhat_network():
    '''Check if we can access the Red Hat network

    This checks if the image server can be accessed. The result gets cached,
    so this can be called several times.
    '''
    if redhat_network.result is None:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        store = urllib.parse.urlparse(REDHAT_STORE)
        try:
            s.connect((store.hostname, store.port))
            redhat_network.result = True
        except OSError:
            redhat_network.result = False

    return redhat_network.result

redhat_network.result = None