# 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/.


"""Utility functions to handle test chunking."""

import functools
import logging
import os
import re
import traceback
from abc import ABCMeta, abstractmethod

from manifestparser import TestManifest
from manifestparser.filters import chunk_by_runtime, tags
from mozinfo.platforminfo import PlatformInfo
from moztest.resolve import TEST_SUITES, TestManifestLoader, TestResolver
from requests.exceptions import RetryError
from taskgraph.util import json
from taskgraph.util.taskcluster import get_artifact_from_index
from taskgraph.util.yaml import load_yaml

from gecko_taskgraph import TEST_CONFIGS
from gecko_taskgraph.util.bugbug import CT_LOW, BugbugTimeoutException, push_schedules

logger = logging.getLogger(__name__)
here = os.path.abspath(os.path.dirname(__file__))
resolver = TestResolver.from_environment(cwd=here, loader_cls=TestManifestLoader)

VARIANTS_YML = os.path.join(TEST_CONFIGS, "variants.yml")
TEST_VARIANTS = {}
if os.path.exists(VARIANTS_YML):
    TEST_VARIANTS = load_yaml(VARIANTS_YML)

WPT_SUBSUITES = {
    "canvas": ["html/canvas"],
    "webgpu": ["_mozilla/webgpu"],
    "webcodecs": ["webcodecs"],
    "eme": ["encrypted-media"],
}


def get_test_tags(config, env):
    tags = json.loads(
        config.params["try_task_config"].get("env", {}).get("MOZHARNESS_TEST_TAG", "[]")
    )
    tags.extend(env.get("MOZHARNESS_TEST_TAG", []))
    return list(set(tags))


def guess_mozinfo_from_task(task, repo="", app_version="", test_tags=[]):
    """Attempt to build a mozinfo dict from a task definition.

    This won't be perfect and many values used in the manifests will be missing. But
    it should cover most of the major ones and be "good enough" for chunking in the
    taskgraph.

    Args:
        task (dict): A task definition.

    Returns:
        A dict that can be used as a mozinfo replacement.
    """
    setting = task["test-setting"]
    runtime_keys = setting["runtime"].keys()

    platform_info = PlatformInfo(setting)

    info = {
        "debug": platform_info.debug,
        "bits": platform_info.bits,
        "asan": setting["build"].get("asan", False),
        "tsan": setting["build"].get("tsan", False),
        "ccov": setting["build"].get("ccov", False),
        "mingwclang": setting["build"].get("mingwclang", False),
        "nightly_build": "a1"
        in app_version,  # https://searchfox.org/mozilla-central/source/build/moz.configure/init.configure#1101
        "release_or_beta": "a" not in app_version,
        "repo": repo,
    }
    # the following are used to evaluate reftest skip-if
    info["webrtc"] = not info["mingwclang"]
    info["opt"] = (
        not info["debug"] and not info["asan"] and not info["tsan"] and not info["ccov"]
    )
    info["os"] = platform_info.os

    # crashreporter is disabled for asan / tsan builds
    if info["asan"] or info["tsan"]:
        info["crashreporter"] = False
    else:
        info["crashreporter"] = True

    info["appname"] = "fennec" if info["os"] == "android" else "firefox"
    info["buildapp"] = "browser"

    # TODO processor being deprecated by arch, remove once finished.
    info["processor"] = info["arch"] = platform_info.arch

    # guess toolkit
    if info["os"] == "android":
        info["toolkit"] = "android"
    elif info["os"] == "win":
        info["toolkit"] = "windows"
    elif info["os"] == "mac":
        info["toolkit"] = "cocoa"
    else:
        info["toolkit"] = "gtk"
        info["display"] = platform_info.display or "x11"

    info["os_version"] = platform_info.os_version

    for variant in TEST_VARIANTS:
        tag = TEST_VARIANTS[variant].get("mozinfo", "")
        if tag == "":
            continue

        value = variant in runtime_keys

        if variant == "1proc":
            value = not value
        elif "fission" in variant:
            value = any(
                "1proc" not in key or "no-fission" not in key for key in runtime_keys
            )
            if "no-fission" not in variant:
                value = not value
        elif tag == "xorigin":
            value = any("xorigin" in key for key in runtime_keys)

        info[tag] = value

    # wpt has canvas and webgpu as tags, lets find those
    for tag in WPT_SUBSUITES.keys():
        if tag in task["test-name"]:
            info[tag] = True
        else:
            info[tag] = False

    # NOTE: as we are using an array here, frozenset() cannot work with a 'list'
    # this is cast to a string
    info["tag"] = json.dumps(test_tags)

    info["automation"] = True
    return info


@functools.cache
def _load_manifest_runtimes_data():
    index_route = "gecko.v2.mozilla-central.latest.source.test-info-manifest-timings"
    return get_artifact_from_index(index_route, "public/manifests-runtimes.json")


@functools.cache
def get_runtimes(platform, suite_name):
    if not suite_name or not platform:
        raise TypeError("suite_name and platform cannot be empty.")

    data = _load_manifest_runtimes_data()

    manifest_runtimes = {}
    job_names = data.get("jobNames", [])
    manifests_data = data.get("manifests", {})

    # Helper to insert -shippable before suffixes like -qr, -lite
    def add_shippable(platform_str):
        if "/opt" not in platform_str or "-shippable" in platform_str:
            return None

        parts = platform_str.rsplit("/", 1)  # ["windows10-64-2009-qr", "opt"]
        platform_part = parts[0]

        # Move suffixes after -shippable
        suffixes_to_move = ["-qr", "-lite"]
        base = platform_part
        suffix = ""
        for s in suffixes_to_move:
            if platform_part.endswith(s):
                base = platform_part[: -len(s)]
                suffix = s
                break

        return f"{base}-shippable{suffix}/{parts[1]}"

    # Build platform candidates to try (exact match first, then fallbacks)
    platform_candidates = [platform]

    # Fallback 1: Add -shippable for /opt builds
    shippable = add_shippable(platform)
    if shippable:
        platform_candidates.append(shippable)

    # Fallback 2: Remove -devedition (devedition jobs may not run on mozilla-central)
    if "-devedition" in platform:
        without_devedition = platform.replace("-devedition", "")
        platform_candidates.append(without_devedition)
        shippable = add_shippable(without_devedition)
        if shippable:
            platform_candidates.append(shippable)
    matched_jobs = []
    used_platform = None

    # Implicit parts of job names that are always present for certain
    # platforms but not included in the suite name by the task graph.
    # Strip these (along with chunk numbers) from job names before matching.
    def _strip_job_name(job_name):
        name = re.sub(r"-\d+$", "", job_name)
        name = name.replace("-geckoview-", "-")
        name = name.replace("-swr", "")
        name = name.replace("-1proc", "")
        return name

    # Try each platform candidate until we find jobs
    for candidate in platform_candidates:
        expected = f"test-{candidate}-{suite_name}"
        matching = [j for j in job_names if _strip_job_name(j) == expected]
        if matching:
            matched_jobs = matching
            used_platform = candidate
            break

    if not matched_jobs:
        logger.warning(
            f"get_runtimes({platform}, {suite_name}): No jobs found. Tried candidates: {platform_candidates}"
        )
        return {}

    # Collect runtimes from matched jobs
    for manifest_name, manifest_info in manifests_data.items():
        jobs = manifest_info.get("jobs", [])
        runtimes_arrays = manifest_info.get("runtimes", [])

        all_runtimes = []
        for job_idx, job_runtimes in enumerate(runtimes_arrays):
            job_name = job_names[jobs[job_idx]]
            if job_name in matched_jobs:
                all_runtimes.extend(job_runtimes)

        # Calculate median runtime
        if all_runtimes:
            all_runtimes.sort()
            mid = len(all_runtimes) // 2
            if len(all_runtimes) % 2 == 0:
                median = (all_runtimes[mid - 1] + all_runtimes[mid]) / 2
            else:
                median = all_runtimes[mid]
            # Convert from milliseconds to seconds
            manifest_runtimes[manifest_name] = median / 1000

    # Log if we used a fallback
    if used_platform != platform:
        logger.debug(
            f"get_runtimes({platform}, {suite_name}): Using fallback platform {used_platform}, matched {len(matched_jobs)} jobs, found {len(manifest_runtimes)} manifests"
        )
    elif len(manifest_runtimes) == 0:
        logger.warning(
            f"get_runtimes({platform}, {suite_name}): Matched {len(matched_jobs)} jobs but found 0 manifests"
        )

    return manifest_runtimes


def resolve_manifest_runtimes(all_runtimes, manifests):
    """Match manifests to their runtimes, aggregating included sub-manifests.

    Runtime data keys can be either "manifest.toml" for direct matches or
    "manifest.toml:included.toml" for included sub-manifests. This function
    aggregates both into a single runtime per parent manifest.

    Args:
        all_runtimes (dict): Raw runtime data from get_runtimes().
        manifests (iterable): Manifest paths to look up.

    Returns:
        A dict mapping manifest paths to their total runtime in seconds.
        Manifests with no runtime data are omitted.
    """
    runtimes = {}
    for manifest in manifests:
        total_runtime = 0
        found = False

        if manifest in all_runtimes:
            total_runtime += all_runtimes[manifest]
            found = True

        if manifest.endswith(".toml"):
            prefix = manifest + ":"
            for key, value in all_runtimes.items():
                if key.startswith(prefix):
                    total_runtime += value
                    found = True

        if found:
            runtimes[manifest] = total_runtime

    return runtimes


def chunk_manifests(suite, platform, chunks, manifests):
    """Run the chunking algorithm.

    Args:
        platform (str): Platform used to find runtime info.
        chunks (int): Number of chunks to split manifests into.
        manifests(list): Manifests to chunk.

    Returns:
        A list of length `chunks` where each item contains a list of manifests
        that run in that chunk.
    """
    all_runtimes = get_runtimes(platform, suite)
    runtimes = resolve_manifest_runtimes(all_runtimes, manifests)

    # Log if some manifests are missing runtime data
    manifests_without_data = [m for m in manifests if m not in runtimes]
    if manifests_without_data and len(runtimes) > 0:
        missing_list = ", ".join(manifests_without_data[:5])
        if len(manifests_without_data) > 5:
            missing_list += f" ... and {len(manifests_without_data) - 5} more"
        logger.warning(
            f"chunk_manifests({suite}, {platform}): Missing runtime data for {len(manifests_without_data)}/{len(manifests)} manifests: {missing_list}"
        )

    # Separate manifests with 0 runtime from those with real data.
    # When we fall back to a similar platform's data, some manifests may
    # not exist in that fallback configuration and end up with 0ms.
    # Spread them evenly across chunks to limit the damage when they
    # actually take significant time.
    zero_runtime_manifests = sorted(m for m in manifests if runtimes.get(m, 0) == 0)
    nonzero_manifests = [m for m in manifests if runtimes.get(m, 0) != 0]

    cbr = chunk_by_runtime(None, chunks, runtimes)
    chunked = [c for _, c in cbr.get_chunked_manifests(nonzero_manifests)]

    for i, m in enumerate(zero_runtime_manifests):
        chunked[i % chunks].append(m)

    return chunked


class BaseManifestLoader(metaclass=ABCMeta):
    def __init__(self, params):
        self.params = params

    @abstractmethod
    def get_manifests(self, flavor, subsuite, mozinfo):
        """Compute which manifests should run for the given flavor, subsuite and mozinfo.

        This function returns skipped manifests separately so that more balanced
        chunks can be achieved by only considering "active" manifests in the
        chunking algorithm.

        Args:
            flavor (str): The suite to run. Values are defined by the 'build_flavor' key
                in `moztest.resolve.TEST_SUITES`.
            subsuite (str): The subsuite to run or 'undefined' to denote no subsuite.
            mozinfo (frozenset): Set of data in the form of (<key>, <value>) used
                                 for filtering.

        Returns:
            A tuple of two manifest lists. The first is the set of active manifests (will
            run at least one test. The second is a list of skipped manifests (all tests are
            skipped).
        """


class DefaultLoader(BaseManifestLoader):
    """Load manifests using metadata from the TestResolver."""

    @functools.cache
    def get_tests(self, suite):
        suite_definition = TEST_SUITES[suite]
        return list(
            resolver.resolve_tests(
                flavor=suite_definition["build_flavor"],
                subsuite=suite_definition.get("kwargs", {}).get(
                    "subsuite", "undefined"
                ),
            )
        )

    @functools.cache
    def get_manifests(self, suite, frozen_mozinfo):
        mozinfo = dict(frozen_mozinfo)

        tests = self.get_tests(suite)

        mozinfo_tags = json.loads(mozinfo.get("tag", "[]"))

        if "web-platform-tests" in suite:
            manifests = set()

            subsuite = next((x for x in WPT_SUBSUITES.keys() if mozinfo.get(x)), None)

            if subsuite:
                subsuite_paths = WPT_SUBSUITES[subsuite]
                for t in tests:
                    if mozinfo_tags and not any(
                        x in t.get("tags", []) for x in mozinfo_tags
                    ):
                        continue

                    manifest = t["manifest"]
                    if any(x in manifest for x in subsuite_paths):
                        manifests.add(manifest)
            else:
                all_subsuite_paths = [
                    path for paths in WPT_SUBSUITES.values() for path in paths
                ]
                for t in tests:
                    if mozinfo_tags and not any(
                        x in t.get("tags", []) for x in mozinfo_tags
                    ):
                        continue

                    manifest = t["manifest"]
                    if not any(path in manifest for path in all_subsuite_paths):
                        manifests.add(manifest)

            return {
                "active": list(manifests),
                "skipped": [],
                "other_dirs": {},
            }

        filters = []
        SUITES_WITHOUT_TAG = {
            "crashtest",
            "crashtest-qr",
            "jsreftest",
            "reftest",
            "reftest-qr",
        }

        # Exclude suites that don't support --tag to prevent manifests from
        # being optimized out, which would result in no jobs being triggered.
        # No need to check suites like gtest, as all suites in compiled.yml
        # have test-manifest-loader set to null, meaning this function is never
        # called.
        # Note there's a similar list in desktop_unittest.py in
        # DesktopUnittest's _query_abs_base_cmd method. The lists should be
        # kept in sync.
        assert suite not in ["gtest", "cppunittest", "jittest"]

        if suite not in SUITES_WITHOUT_TAG and mozinfo_tags:
            filters.extend([tags([x]) for x in mozinfo_tags])

        m = TestManifest()
        m.tests = tests
        active_tests = m.active_tests(
            disabled=False, exists=False, filters=filters, **mozinfo
        )

        active_manifests = {chunk_by_runtime.get_manifest(t) for t in active_tests}

        skipped_manifests = {chunk_by_runtime.get_manifest(t) for t in tests}
        skipped_manifests.difference_update(active_manifests)
        return {
            "active": list(active_manifests),
            "skipped": list(skipped_manifests),
            "other_dirs": {},
        }


class BugbugLoader(DefaultLoader):
    """Load manifests using metadata from the TestResolver, and then
    filter them based on a query to bugbug."""

    CONFIDENCE_THRESHOLD = CT_LOW

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.timedout = False

    @functools.cache
    def get_manifests(self, suite, mozinfo):
        manifests = super().get_manifests(suite, mozinfo)

        # Don't prune any manifests if we're on a backstop push or there was a timeout.
        if self.params["backstop"] or self.timedout:
            return manifests

        try:
            data = push_schedules(self.params["project"], self.params["head_rev"])
        except (BugbugTimeoutException, RetryError):
            traceback.print_exc()
            logger.warning("Timed out waiting for bugbug, loading all test manifests.")
            self.timedout = True
            return self.get_manifests(suite, mozinfo)

        bugbug_manifests = {
            m
            for m, c in data.get("groups", {}).items()
            if c >= self.CONFIDENCE_THRESHOLD
        }

        manifests["active"] = list(set(manifests["active"]) & bugbug_manifests)
        manifests["skipped"] = list(set(manifests["skipped"]) & bugbug_manifests)
        return manifests


manifest_loaders = {
    "bugbug": BugbugLoader,
    "default": DefaultLoader,
}

_loader_cache = {}


def get_manifest_loader(name, params):
    # Ensure we never create more than one instance of the same loader type for
    # performance reasons.
    if name in _loader_cache:
        return _loader_cache[name]

    loader = manifest_loaders[name](dict(params))
    _loader_cache[name] = loader
    return loader