"""ORCH-6: Project registry — map Plane project id -> repo / work-item prefix.

Root cause of the 2026-06-02 incident: the Plane webhook listened to the whole
workspace and hardcoded ``repo = settings.default_repo`` (enduro-trails). Every
issue from any project was funneled into one repo with one prefix (ET).

This module introduces a small registry keyed by the Plane project uuid so the
orchestrator can:
  * filter webhooks by project (ignore unknown projects),
  * resolve the gitea repo + work-item prefix for a known project,
  * route Plane sync (state/comment) into the issue's own project.

Source of truth: ``settings.projects_json`` (a JSON array set via the
``ORCH_PROJECTS_JSON`` env var). If unset/empty/invalid, a built-in default
registry is used so the system works out of the box.
"""

import json
import logging
from dataclasses import dataclass

from .config import settings

logger = logging.getLogger("orchestrator.projects")


@dataclass(frozen=True)
class ProjectConfig:
    plane_project_id: str   # uuid of the Plane project (registry key)
    repo: str               # gitea repo name (== folder under /repos)
    work_item_prefix: str   # ET / ORCH
    name: str               # human-readable label


# Built-in default registry (used when ORCH_PROJECTS_JSON is empty/invalid).
# Keep enduro-trails first so existing behaviour is the safe default.
_DEFAULT_PROJECTS = [
    ProjectConfig(
        plane_project_id="7a79f0a9-5278-49cd-9007-9a338f238f9c",
        repo="enduro-trails",
        work_item_prefix="ET",
        name="enduro-trails",
    ),
    ProjectConfig(
        plane_project_id="8da6aa25-a60e-44d6-a1e2-d8ae59aa7d6a",
        repo="orchestrator",
        work_item_prefix="ORCH",
        name="orchestrator",
    ),
]


def _parse_projects_json(raw: str) -> list[ProjectConfig] | None:
    """Parse ORCH_PROJECTS_JSON. Returns None if empty/invalid (-> use default)."""
    if not raw or not raw.strip():
        return None
    try:
        data = json.loads(raw)
    except (ValueError, TypeError) as e:
        logger.error(f"ORCH_PROJECTS_JSON is not valid JSON, falling back to default: {e}")
        return None
    if not isinstance(data, list):
        logger.error("ORCH_PROJECTS_JSON must be a JSON array, falling back to default")
        return None

    parsed: list[ProjectConfig] = []
    for i, item in enumerate(data):
        if not isinstance(item, dict):
            logger.error(f"ORCH_PROJECTS_JSON[{i}] is not an object, skipping")
            continue
        try:
            parsed.append(
                ProjectConfig(
                    plane_project_id=str(item["plane_project_id"]),
                    repo=str(item["repo"]),
                    work_item_prefix=str(item["work_item_prefix"]),
                    name=str(item.get("name", item["repo"])),
                )
            )
        except KeyError as e:
            logger.error(f"ORCH_PROJECTS_JSON[{i}] missing required key {e}, skipping")
            continue
    if not parsed:
        logger.error("ORCH_PROJECTS_JSON produced no valid entries, falling back to default")
        return None
    return parsed


def _load_projects() -> list[ProjectConfig]:
    parsed = _parse_projects_json(getattr(settings, "projects_json", "") or "")
    if parsed is not None:
        logger.info(f"Project registry loaded from ORCH_PROJECTS_JSON: {len(parsed)} project(s)")
        return parsed
    return list(_DEFAULT_PROJECTS)


# Module-level registry, built once at import.
PROJECTS: list[ProjectConfig] = _load_projects()
_BY_PLANE_ID: dict[str, ProjectConfig] = {p.plane_project_id: p for p in PROJECTS}
_BY_REPO: dict[str, ProjectConfig] = {p.repo: p for p in PROJECTS}


def get_project_by_plane_id(plane_project_id: str) -> ProjectConfig | None:
    """Resolve project config by Plane project uuid. None if unknown."""
    if not plane_project_id:
        return None
    return _BY_PLANE_ID.get(plane_project_id)


def get_project_by_repo(repo: str) -> ProjectConfig | None:
    """Resolve project config by gitea repo name. None if unknown."""
    if not repo:
        return None
    return _BY_REPO.get(repo)


def known_plane_project_ids() -> set[str]:
    """Set of Plane project ids the orchestrator is configured to handle."""
    return set(_BY_PLANE_ID.keys())


def reload_projects() -> None:
    """Rebuild the registry from current settings (used by tests)."""
    global PROJECTS, _BY_PLANE_ID, _BY_REPO
    PROJECTS = _load_projects()
    _BY_PLANE_ID = {p.plane_project_id: p for p in PROJECTS}
    _BY_REPO = {p.repo: p for p in PROJECTS}