# 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/.


import itertools
import json
import logging
import math

import taskgraph
from mozbuild.util import memoize
from mozpack.path import match as mozpackmatch

from gecko_taskgraph import files_changed

from .. import GECKO

logger = logging.getLogger(__name__)


@memoize
def perfile_number_of_chunks(is_try, try_task_config, head_repository, head_rev, type):
    if taskgraph.fast and not is_try:
        # When iterating on taskgraph changes, the exact number of chunks that
        # test-verify runs usually isn't important, so skip it when going fast.
        return 3
    tests_per_chunk = 10.0
    if type.startswith("test-coverage"):
        tests_per_chunk = 30.0

    if type.startswith("test-verify-wpt") or type.startswith("test-coverage-wpt"):
        file_patterns = [
            "testing/web-platform/tests/**",
            "testing/web-platform/mozilla/tests/**",
        ]
    elif type.startswith("test-verify-gpu") or type.startswith("test-coverage-gpu"):
        file_patterns = [
            "**/*webgl*/**/test_*",
            "**/dom/canvas/**/test_*",
            "**/gfx/tests/**/test_*",
            "**/devtools/canvasdebugger/**/browser_*",
            "**/reftest*/**",
        ]
    elif type.startswith("test-verify") or type.startswith("test-coverage"):
        file_patterns = [
            "**/test_*",
            "**/browser_*",
            "**/crashtest*/**",
            "js/src/tests/test/**",
            "js/src/tests/non262/**",
            "js/src/tests/test262/**",
        ]
    else:
        # Returning 0 means no tests to run, this captures non test-verify tasks
        return 1

    changed_files = set()
    if try_task_config:
        suite_to_paths = json.loads(try_task_config)
        specified_files = itertools.chain.from_iterable(suite_to_paths.values())
        changed_files.update(specified_files)

    if is_try:
        changed_files.update(files_changed.get_locally_changed_files(GECKO))
    else:
        changed_files.update(files_changed.get_changed_files(head_repository, head_rev))

    test_count = 0
    for pattern in file_patterns:
        for path in changed_files:
            # TODO: consider running tests if a manifest changes
            if path.endswith(".list") or path.endswith(".ini"):
                continue
            if path.endswith("^headers^"):
                continue

            if mozpackmatch(path, pattern):
                gpu = False
                if type == "test-verify-e10s" or type == "test-coverage-e10s":
                    # file_patterns for test-verify will pick up some gpu tests, lets ignore
                    # in the case of reftest, we will not have any in the regular case
                    gpu_dirs = [
                        "dom/canvas",
                        "gfx/tests",
                        "devtools/canvasdebugger",
                        "webgl",
                    ]
                    for gdir in gpu_dirs:
                        if len(path.split(gdir)) > 1:
                            gpu = True

                if not gpu:
                    test_count += 1

    chunks = test_count / tests_per_chunk
    chunks = int(math.ceil(chunks))

    # Never return 0 chunks on try, so that per-file tests can be pushed to try with
    # an explicit path, and also so "empty" runs can be checked on try.
    if is_try and chunks == 0:
        chunks = 1

    return chunks