from __future__ import annotations

from flask import g, jsonify, request

from app import db
from app.api.system import bp
from app.core.governance.responsibilities import (
    ResponsibilityConflict,
    ResponsibilityService,
    ResponsibilityUserUnavailable,
    ResponsibilityValidationError,
    SqlAlchemyResponsibilityRepository,
)
from app.core.system.permissions import (
    RESPONSIBILITIES_MANAGE,
    RESPONSIBILITIES_READ,
    require_permissions,
)
from app.models.result import failed, success


def _service() -> ResponsibilityService:
    return ResponsibilityService(SqlAlchemyResponsibilityRepository(db.session))


def _etag(response, revision: int):
    response.headers["ETag"] = f'"{int(revision)}"'
    return response


def _expected_revision() -> int:
    raw = str(request.headers.get("If-Match") or "").strip()
    if raw.startswith("W/"):
        raw = raw[2:].strip()
    raw = raw.strip('"')
    if not raw or not raw.isdigit():
        raise ResponsibilityValidationError("missing valid If-Match revision")
    return int(raw)


@bp.route(
    "/responsibilities/<resource_type>/<resource_uid>",
    methods=["GET"],
)
@require_permissions(RESPONSIBILITIES_READ)
def get_responsibility_matrix(resource_type: str, resource_uid: str):
    try:
        result = _service().get(resource_type, resource_uid)
        return _etag(jsonify(success(result)), result["revision"])
    except ResponsibilityValidationError as exc:
        return jsonify(failed(str(exc), code=400)), 400


@bp.route(
    "/responsibilities/<resource_type>/<resource_uid>",
    methods=["PUT"],
)
@require_permissions(RESPONSIBILITIES_MANAGE)
def replace_responsibility_matrix(resource_type: str, resource_uid: str):
    try:
        revision = _expected_revision()
        body = request.get_json(silent=True) or {}
        result = _service().replace(
            resource_type=resource_type,
            resource_uid=resource_uid,
            assignments=body.get("assignments"),
            expected_revision=revision,
            actor_uid=g.current_user["id"],
        )
        db.session.commit()
        return _etag(jsonify(success(result, "责任矩阵已更新")), result["revision"])
    except ResponsibilityConflict as exc:
        db.session.rollback()
        return jsonify(failed(str(exc), code=409)), 409
    except ResponsibilityUserUnavailable as exc:
        db.session.rollback()
        return jsonify(failed(str(exc), code=422)), 422
    except ResponsibilityValidationError as exc:
        db.session.rollback()
        status = 428 if "If-Match" in str(exc) else 400
        return jsonify(failed(str(exc), code=status)), status