# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

from __future__ import absolute_import, print_function, unicode_literals

import os
import json
import sys
import time

import requests
from mozbuild.util import memoize

from taskgraph.util.taskcluster import requests_retry_session

try:
    # TODO(py3): use time.monotonic()
    from time import monotonic
except ImportError:
    from time import time as monotonic

BUGBUG_BASE_URL = "https://bugbug.herokuapp.com"
RETRY_TIMEOUT = 9 * 60  # seconds
RETRY_INTERVAL = 10  # seconds

# Preset confidence thresholds.
CT_LOW = 0.7
CT_MEDIUM = 0.8
CT_HIGH = 0.9

GROUP_TRANSLATIONS = {
    "testing/web-platform/tests": "",
    "testing/web-platform/mozilla/tests": "/_mozilla",
}


def translate_group(group):
    for prefix, value in GROUP_TRANSLATIONS.items():
        if group.startswith(prefix):
            return group.replace(prefix, value)

    return group


class BugbugTimeoutException(Exception):
    pass


@memoize
def get_session():
    s = requests.Session()
    s.headers.update({"X-API-KEY": "gecko-taskgraph"})
    return requests_retry_session(retries=5, session=s)


def _write_perfherder_data(lower_is_better):
    if os.environ.get("MOZ_AUTOMATION", "0") == "1":
        perfherder_data = {
            "framework": {"name": "build_metrics"},
            "suites": [
                {
                    "name": suite,
                    "value": value,
                    "lowerIsBetter": True,
                    "shouldAlert": False,
                    "subtests": [],
                }
                for suite, value in lower_is_better.items()
            ],
        }
        print(
            "PERFHERDER_DATA: {}".format(json.dumps(perfherder_data)), file=sys.stderr
        )


@memoize
def push_schedules(branch, rev):
    url = BUGBUG_BASE_URL + "/push/{branch}/{rev}/schedules".format(
        branch=branch, rev=rev
    )
    start = monotonic()
    session = get_session()

    # On try there is no fallback and pulling is slower, so we allow bugbug more
    # time to compute the results.
    # See https://github.com/mozilla/bugbug/issues/1673.
    timeout = RETRY_TIMEOUT
    if branch == "try":
        timeout += int(timeout / 3)

    attempts = timeout / RETRY_INTERVAL
    i = 0
    while i < attempts:
        r = session.get(url)
        r.raise_for_status()

        if r.status_code != 202:
            break

        time.sleep(RETRY_INTERVAL)
        i += 1
    end = monotonic()

    _write_perfherder_data(
        lower_is_better={
            "bugbug_push_schedules_time": end - start,
            "bugbug_push_schedules_retries": i,
        }
    )

    data = r.json()
    if r.status_code == 202:
        raise BugbugTimeoutException(
            "Timed out waiting for result from '{}'".format(url)
        )

    if "groups" in data:
        data["groups"] = {translate_group(k): v for k, v in data["groups"].items()}

    if "config_groups" in data:
        data["config_groups"] = {
            translate_group(k): v for k, v in data["config_groups"].items()
        }

    return data