"""Detect and rewrite outdated Docker image `version:` tags in
`roles/*/meta/services.yml`.

Counterpart to :mod:`utils.update.repository` (which handles git refs).
Both share the semver primitives in :mod:`utils.update.base`; this
module owns the Docker-Hub / GHCR registry lookups and the YAML
walker that rewrites the matching ``version:`` line.

Suppress a check by placing ``# nocheck: docker-version`` on the line
directly above the ``version:`` key.

A ``version`` that names its own upstream in an ``update:`` block belongs to
:mod:`utils.update.source` and is not collected here.
"""

from __future__ import annotations

import concurrent.futures
import http.client
import json
import re
import time
import urllib.error
import urllib.request
from collections import defaultdict
from dataclasses import dataclass
from typing import TYPE_CHECKING
from urllib.parse import quote, urlencode

import yaml

from utils.annotations.suppress import is_suppressed_at
from utils.cache.files import read_text
from utils.cache.yaml import load_yaml
from utils.docker.image.discovery import iter_role_images
from utils.docker.image.ref import (
    DOCKER_HUB_REGISTRIES,
    GHCR_REGISTRY,
    MCR_REGISTRY,
    split_registry_and_name,
)
from utils.docker.registry import fetch_registry_tags
from utils.roles.mapping import ROLE_FILE_META_SERVICES
from utils.update.base import (
    declares_source,
    is_maintained,
    is_semver,
    latest_semver,
    resolve_max_fetch_workers,
    version_depth,
    version_flavor,
    version_key,
)

if TYPE_CHECKING:
    from pathlib import Path

_KEY_RE = re.compile(r"^(?P<indent>\s*)(?P<key>[A-Za-z0-9_-]+):(?P<rest>.*)$")
_VERSION_VALUE_RE = re.compile(
    r"^(?P<prefix>\s*version\s*:\s*)"
    r"(?P<quote>[\"']?)(?P<value>[^\"'#\s]+)(?P=quote)"
    r"(?P<suffix>\s*(?:#.*)?)$"
)


@dataclass(frozen=True)
class DockerImageVersionEntry:
    role: str
    service: str
    image: str
    version: str
    config_path: Path


@dataclass(frozen=True)
class DockerImageVersionUpdate:
    entry: DockerImageVersionEntry
    latest: str


def is_dockerhub(image: str) -> bool:
    parsed = split_registry_and_name(image)
    if parsed is None:
        return False
    registry, _name = parsed
    return registry is None or registry in DOCKER_HUB_REGISTRIES


def dockerhub_repo(image: str) -> str:
    parsed = split_registry_and_name(image)
    if parsed is None:
        raise ValueError(f"Invalid Docker image reference: {image!r}")
    registry, name = parsed
    if registry is not None and registry not in DOCKER_HUB_REGISTRIES:
        raise ValueError(f"Image is not a Docker Hub reference: {image!r}")
    return name if "/" in name else f"library/{name}"


def fetch_dockerhub_tags(image: str, max_pages: int = 5) -> list[str]:
    repo = dockerhub_repo(image)
    tags: list[str] = []
    for page in range(1, max_pages + 1):
        url = (
            f"https://hub.docker.com/v2/repositories/{repo}/tags/"
            f"?page_size=100&page={page}"
        )
        req = urllib.request.Request(
            url, headers={"User-Agent": "infinito-nexus-version-updater"}
        )
        try:
            with urllib.request.urlopen(req, timeout=15) as resp:  # noqa: S310
                if resp.status == 429:
                    time.sleep(2)
                    continue
                body = json.loads(resp.read().decode())
        except (
            urllib.error.URLError,
            OSError,
            http.client.HTTPException,
            json.JSONDecodeError,
        ):
            break
        tags.extend(item["name"] for item in body.get("results", []))
        if not body.get("next"):
            break
    return tags


def is_ghcr(image: str) -> bool:
    parsed = split_registry_and_name(image)
    return parsed is not None and parsed[0] == GHCR_REGISTRY


def ghcr_repo(image: str) -> str:
    parsed = split_registry_and_name(image)
    if parsed is None or parsed[0] != GHCR_REGISTRY:
        raise ValueError(f"Image is not a GHCR reference: {image!r}")
    return parsed[1]


def fetch_ghcr_tags(image: str) -> list[str]:
    name = ghcr_repo(image)
    token_query = urlencode(
        {"scope": f"repository:{name}:pull", "service": GHCR_REGISTRY}
    )
    token_url = f"https://{GHCR_REGISTRY}/token?{token_query}"
    try:
        req = urllib.request.Request(
            token_url, headers={"User-Agent": "infinito-nexus-version-updater"}
        )
        with urllib.request.urlopen(req, timeout=15) as resp:  # noqa: S310
            token_body = json.loads(resp.read().decode())
        token = token_body.get("token") or token_body.get("access_token")
    except (
        urllib.error.URLError,
        OSError,
        http.client.HTTPException,
        json.JSONDecodeError,
    ):
        return []

    if not token:
        return []

    tags_url = f"https://{GHCR_REGISTRY}/v2/{quote(name, safe='/')}/tags/list"
    req = urllib.request.Request(
        tags_url,
        headers={
            "Authorization": f"Bearer {token}",
            "User-Agent": "infinito-nexus-version-updater",
        },
    )
    try:
        with urllib.request.urlopen(req, timeout=15) as resp:  # noqa: S310
            body = json.loads(resp.read().decode())
    except (
        urllib.error.URLError,
        OSError,
        http.client.HTTPException,
        json.JSONDecodeError,
    ):
        return []

    return body.get("tags") or []


def is_mcr(image: str) -> bool:
    parsed = split_registry_and_name(image)
    return parsed is not None and parsed[0] == MCR_REGISTRY


def is_supported_registry(image: str) -> bool:
    """Whether *image* resolves to a registry the generic v2 client can query."""
    return split_registry_and_name(image) is not None


def mcr_repo(image: str) -> str:
    parsed = split_registry_and_name(image)
    if parsed is None or parsed[0] != MCR_REGISTRY:
        raise ValueError(f"Image is not an MCR reference: {image!r}")
    return parsed[1]


_LINK_NEXT_RE = re.compile(r'<([^>]+)>\s*;\s*rel="next"', re.IGNORECASE)


def fetch_mcr_tags(image: str, max_pages: int = 10) -> list[str]:
    name = mcr_repo(image)
    base = f"https://{MCR_REGISTRY}"
    url = f"{base}/v2/{quote(name, safe='/')}/tags/list?n=100"
    tags: list[str] = []
    for _ in range(max_pages):
        req = urllib.request.Request(  # noqa: S310
            url, headers={"User-Agent": "infinito-nexus-version-updater"}
        )
        try:
            with urllib.request.urlopen(req, timeout=15) as resp:  # noqa: S310
                body = json.loads(resp.read().decode())
                link_header = resp.headers.get("Link", "")
        except (
            urllib.error.URLError,
            OSError,
            http.client.HTTPException,
            json.JSONDecodeError,
        ):
            break
        tags.extend(body.get("tags") or [])
        match = _LINK_NEXT_RE.search(link_header)
        if not match:
            break
        next_link = match.group(1)
        url = next_link if next_link.startswith("http") else f"{base}{next_link}"
    return tags


def suppressed_services(config_path: Path) -> set[str]:
    """Return service names whose ``version:`` line is annotated with
    the unified ``# nocheck: docker-version`` marker.

    The file root of ``meta/services.yml`` IS the services map; there
    is no ``services.`` wrapper to walk into.
    """
    raw = read_text(str(config_path))
    lines = raw.splitlines()

    suppressed_lines: set[int] = {
        index
        for index, line in enumerate(lines)
        if re.search(r"^\s+version\s*:", line)
        and is_suppressed_at(lines, index + 1, "docker-version")
    }

    if not suppressed_lines:
        return set()

    root = yaml.compose(raw)
    if not isinstance(root, yaml.MappingNode):
        return set()

    names: set[str] = set()
    for service_key, service_value in root.value:
        if not isinstance(service_value, yaml.MappingNode):
            continue
        for field_key, _field_value in service_value.value:
            if (
                field_key.value == "version"
                and field_key.start_mark.line in suppressed_lines
            ):
                names.add(service_key.value)
    return names


def sourced_services(config_path: Path) -> set[str]:
    """Return service names whose ``version`` declares its own upstream.

    Args:
        config_path: a role's ``meta/services.yml``.
    """
    services = load_yaml(str(config_path)) or {}
    return {
        str(service)
        for service, config in services.items()
        if declares_source(config, "version")
    }


def collect_entries(repo_root: Path) -> list[DockerImageVersionEntry]:
    roles_root = repo_root / "roles"
    entries: list[DockerImageVersionEntry] = []

    for ref in iter_role_images(repo_root):
        if ref.source_file != ROLE_FILE_META_SERVICES:
            continue
        if not is_semver(ref.version):
            continue
        if not is_maintained(roles_root, ref.role):
            continue

        config_path = roles_root / ref.role / ROLE_FILE_META_SERVICES
        if ref.service in suppressed_services(config_path):
            continue
        if ref.service in sourced_services(config_path):
            continue

        if ref.registry == "docker.io":
            image = ref.name
        else:
            image = f"{ref.registry}/{ref.name}"

        entries.append(
            DockerImageVersionEntry(
                role=ref.role,
                service=ref.service,
                image=image,
                version=ref.version,
                config_path=config_path,
            )
        )

    return entries


def _registry_cursor(version: str) -> str | None:
    """Pagination seed for the generic v2 tag scan.

    Returns ``"v"`` for v-prefixed pins so the scan skips ahead of
    commit-sha tags that sort before the release tags, ``None``
    otherwise (scan from the first page).
    """
    return "v" if version.startswith("v") else None


def find_outdated_updates(repo_root: Path) -> list[DockerImageVersionUpdate]:
    entries = collect_entries(repo_root)
    updates: list[DockerImageVersionUpdate] = []

    def _fetch(item: tuple[str, str]) -> tuple[str, list[str]]:
        image, version = item
        if is_dockerhub(image):
            return image, fetch_dockerhub_tags(image)
        if is_ghcr(image):
            return image, fetch_ghcr_tags(image)
        if is_mcr(image):
            return image, fetch_mcr_tags(image)
        return image, fetch_registry_tags(image, last=_registry_cursor(version))

    image_versions: dict[str, str] = {}
    for entry in entries:
        if is_supported_registry(entry.image):
            image_versions.setdefault(entry.image, entry.version)
    with concurrent.futures.ThreadPoolExecutor(
        max_workers=resolve_max_fetch_workers()
    ) as pool:
        image_tags: dict[str, list[str]] = dict(
            pool.map(_fetch, image_versions.items())
        )

    for entry in entries:
        tags = image_tags.get(entry.image, [])
        if not tags:
            continue
        latest = latest_semver(
            tags,
            version_depth(entry.version),
            version_flavor(entry.version),
        )
        if latest and version_key(entry.version) < version_key(latest):
            updates.append(DockerImageVersionUpdate(entry=entry, latest=latest))

    return _held_to_release_groups(updates, image_tags)


def _held_to_release_groups(
    updates: list[DockerImageVersionUpdate], image_tags: dict[str, list[str]]
) -> list[DockerImageVersionUpdate]:
    """Hold every member of a release group to the newest tag all of them
    publish.

    Several images of one role that currently sit on the same version are one
    product released together (the four Jitsi components, the six GitLab CNG
    images). Upstream does not push them atomically, so a run that lands in the
    window between the first and the last push would raise the ones already
    there and leave the rest behind, deploying a mixed set.

    Args:
        updates: the per-entry candidates, before grouping.
        image_tags: every tag fetched per image, keyed as in the caller.

    Returns:
        The updates, each group lowered to its common newest tag, and dropped
        entirely where the group shares no newer tag at all.
    """
    groups: dict[tuple[str, str], list[DockerImageVersionUpdate]] = defaultdict(list)
    for update in updates:
        groups[(update.entry.role, update.entry.version)].append(update)

    held: list[DockerImageVersionUpdate] = []
    for group in groups.values():
        if len(group) == 1:
            held.extend(group)
            continue
        shared = set.intersection(
            *(set(image_tags.get(update.entry.image, [])) for update in group)
        )
        current = group[0].entry.version
        common = latest_semver(
            sorted(shared), version_depth(current), version_flavor(current)
        )
        if not common or version_key(current) >= version_key(common):
            continue
        held.extend(
            DockerImageVersionUpdate(entry=update.entry, latest=common)
            for update in group
        )

    return held


def update_config_versions(config_path: Path, service_versions: dict[str, str]) -> bool:
    """Rewrite each ``<service>.version:`` value in ``meta/services.yml``.

    The file root IS the services map (no ``services.`` wrapper), so the
    walker tracks one nesting level: top-level service keys and their
    immediate ``version:`` field.
    """
    lines = config_path.read_text(  # nocheck: cache-read — read-then-write of the same file; cached read would go stale
        encoding="utf-8"
    ).splitlines(keepends=True)
    changed = False

    services_indent: int = 0
    current_service: str | None = None
    current_service_indent: int | None = None

    for index, line in enumerate(lines):
        match = _KEY_RE.match(line)
        if match is None:
            continue

        indent = len(match.group("indent"))
        key = match.group("key")

        if indent == services_indent:
            current_service = key
            current_service_indent = indent
            continue

        if current_service is None or current_service_indent is None:
            continue

        if indent <= current_service_indent:
            current_service = None
            current_service_indent = None
            continue

        if key != "version" or indent != current_service_indent + 2:
            continue

        replacement = service_versions.get(current_service)
        if replacement is None:
            continue

        version_match = _VERSION_VALUE_RE.match(line.rstrip("\n"))
        if version_match is None:
            continue

        quote = version_match.group("quote")
        current_value = version_match.group("value")
        if current_value == replacement:
            continue

        suffix = version_match.group("suffix")
        new_line = f"{version_match.group('prefix')}{quote}{replacement}{quote}{suffix}"
        if line.endswith("\n"):
            new_line += "\n"
        lines[index] = new_line
        changed = True

    if changed:
        config_path.write_text("".join(lines), encoding="utf-8")

    return changed


def apply_updates(updates: list[DockerImageVersionUpdate]) -> list[Path]:
    grouped: dict[Path, dict[str, str]] = {}
    for update in updates:
        grouped.setdefault(update.entry.config_path, {})[update.entry.service] = (
            update.latest
        )

    changed_paths: list[Path] = []
    for config_path, service_versions in sorted(grouped.items()):
        if update_config_versions(config_path, service_versions):
            changed_paths.append(config_path)
    return changed_paths