"""Unified governance work-center API."""

from __future__ import annotations

from flask import g, jsonify, request

from app import db
from app.api.system import bp
from app.core.events.email_delivery import smtp_sender
from app.core.governance.work_center import UnifiedWorkCenterService
from app.core.governance.work_center_repository import SqlAlchemyWorkCenterRepository
from app.core.system.permissions import (
    WORK_CENTER_MANAGE,
    WORK_CENTER_OPERATE,
    WORK_CENTER_READ,
    permissions_for_roles,
    require_permissions,
)
from app.models.result import failed, success


def _service():
    return UnifiedWorkCenterService(
        SqlAlchemyWorkCenterRepository(db.session),
        commit=db.session.commit,
        rollback=db.session.rollback,
    )


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


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


def _error(exc):
    db.session.rollback()
    if "If-Match" in str(exc):
        status = 428
    elif isinstance(exc, LookupError):
        status = 404
    elif isinstance(exc, PermissionError):
        status = 403
    elif isinstance(exc, RuntimeError):
        status = 409
    else:
        status = 400
    return jsonify(failed(str(exc), code=status)), status


@bp.route("/work-center/workflows", methods=["GET"])
@require_permissions(WORK_CENTER_READ)
def list_work_center_workflows():
    return jsonify(success(_service().list_workflows()))


@bp.route("/work-center/workflows", methods=["POST"])
@require_permissions(WORK_CENTER_MANAGE)
def create_work_center_workflow():
    try:
        result = _service().create_workflow(
            request.get_json(silent=True) or {}, actor_uid=g.current_user["id"]
        )
        return _etag(jsonify(success(result, "流程草稿已创建", code=201)), 1), 201
    except (ValueError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/workflows/<workflow_uid>/revisions", methods=["POST"])
@require_permissions(WORK_CENTER_MANAGE)
def revise_work_center_workflow(workflow_uid):
    try:
        result = _service().revise_workflow(
            workflow_uid,
            request.get_json(silent=True) or {},
            expected_version=_expected_version(),
            actor_uid=g.current_user["id"],
        )
        return _etag(jsonify(success(result, "流程版本已创建")), result["current_version"])
    except (ValueError, LookupError, PermissionError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/workflows/<workflow_uid>/publish", methods=["POST"])
@require_permissions(WORK_CENTER_MANAGE)
def publish_work_center_workflow(workflow_uid):
    try:
        result = _service().publish_workflow(
            workflow_uid,
            expected_version=_expected_version(),
            actor_uid=g.current_user["id"],
        )
        return _etag(jsonify(success(result, "流程版本已发布")), result["current_version"])
    except (ValueError, LookupError, PermissionError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/tasks", methods=["GET"])
@require_permissions(WORK_CENTER_READ)
def list_work_center_tasks():
    permissions = permissions_for_roles(g.current_user.get("roles", []))
    filters = {
        key: request.args.get(key)
        for key in ("status", "task_type", "subject_type", "assignee_uid")
        if request.args.get(key)
    }
    filters.update(
        {
            "requester_uid": g.current_user["id"],
            "can_manage": WORK_CENTER_MANAGE in permissions,
        }
    )
    return jsonify(success(_service().list_tasks(**filters)))


@bp.route("/work-center/tasks", methods=["POST"])
@require_permissions(WORK_CENTER_OPERATE)
def create_work_center_task():
    try:
        result = _service().create_task(
            request.get_json(silent=True) or {}, actor_uid=g.current_user["id"]
        )
        return _etag(jsonify(success(result, "统一任务已创建", code=201)), result["current_version"]), 201
    except (ValueError, LookupError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/tasks/<task_uid>", methods=["GET"])
@require_permissions(WORK_CENTER_READ)
def get_work_center_task(task_uid):
    try:
        permissions = permissions_for_roles(g.current_user.get("roles", []))
        result = _service().task_detail(
            task_uid,
            requester_uid=g.current_user["id"],
            can_manage=WORK_CENTER_MANAGE in permissions,
        )
        return _etag(jsonify(success(result)), result["current_version"])
    except (ValueError, LookupError) as exc:
        return _error(exc)


def _task_action(task_uid, action):
    service = _service()
    body = request.get_json(silent=True) or {}
    arguments = {
        "expected_version": _expected_version(),
        "actor_uid": g.current_user["id"],
    }
    if action == "review":
        return service.review_task(task_uid, body, **arguments)
    if action == "transfer":
        return service.transfer_review(task_uid, body, **arguments)
    if action == "close":
        return service.close_task(task_uid, body, **arguments)
    return service.reopen_task(task_uid, body, **arguments)


@bp.route("/work-center/tasks/<task_uid>/<action>", methods=["POST"])
@require_permissions(WORK_CENTER_OPERATE)
def operate_work_center_task(task_uid, action):
    if action not in {"review", "transfer", "close", "reopen"}:
        return jsonify(failed("unsupported task action", code=404)), 404
    try:
        result = _task_action(task_uid, action)
        return _etag(jsonify(success(result, "任务状态已更新")), result["current_version"])
    except (ValueError, LookupError, PermissionError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/tasks/<task_uid>/comments", methods=["POST"])
@require_permissions(WORK_CENTER_OPERATE)
def add_work_center_comment(task_uid):
    try:
        result = _service().add_comment(
            task_uid,
            request.get_json(silent=True) or {},
            actor_uid=g.current_user["id"],
        )
        return jsonify(success(result, "评论已添加", code=201)), 201
    except (ValueError, LookupError, PermissionError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/tasks/<task_uid>/attachments", methods=["POST"])
@require_permissions(WORK_CENTER_OPERATE)
def add_work_center_attachment(task_uid):
    try:
        result = _service().add_attachment(
            task_uid,
            request.get_json(silent=True) or {},
            actor_uid=g.current_user["id"],
        )
        return jsonify(success(result, "附件证据已登记", code=201)), 201
    except (ValueError, LookupError, PermissionError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/timeouts/process", methods=["POST"])
@require_permissions(WORK_CENTER_MANAGE)
def process_work_center_timeouts():
    try:
        body = request.get_json(silent=True) or {}
        return jsonify(
            success(
                _service().process_timeouts(
                    at=body.get("at"), actor_uid=g.current_user["id"]
                ),
                "逾期任务已处理",
            )
        )
    except (ValueError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/notifications", methods=["GET"])
@require_permissions(WORK_CENTER_READ)
def list_work_center_notifications():
    return jsonify(
        success(
            _service().list_notifications(
                g.current_user["id"],
                unread_only=request.args.get("unread_only") == "true",
            )
        )
    )


@bp.route("/work-center/notifications/<notification_uid>/read", methods=["POST"])
@require_permissions(WORK_CENTER_OPERATE)
def read_work_center_notification(notification_uid):
    try:
        return jsonify(
            success(
                _service().mark_notification_read(
                    notification_uid, actor_uid=g.current_user["id"]
                ),
                "消息已读",
            )
        )
    except (ValueError, LookupError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/notifications/deliver", methods=["POST"])
@require_permissions(WORK_CENTER_MANAGE)
def deliver_work_center_notifications():
    try:
        body = request.get_json(silent=True) or {}
        result = _service().deliver_notifications(
            "email", smtp_sender, at=body.get("at"), limit=body.get("limit", 50)
        )
        return jsonify(success(result, "邮件投递批次已处理"))
    except (ValueError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/templates", methods=["GET"])
@require_permissions(WORK_CENTER_READ)
def list_work_center_templates():
    return jsonify(success(_service().list_notification_templates()))


@bp.route("/work-center/templates", methods=["POST"])
@require_permissions(WORK_CENTER_MANAGE)
def create_work_center_template():
    try:
        result = _service().create_notification_template(
            request.get_json(silent=True) or {}, actor_uid=g.current_user["id"]
        )
        return _etag(jsonify(success(result, "通知模板已创建", code=201)), 1), 201
    except (ValueError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/templates/<template_uid>", methods=["PATCH"])
@require_permissions(WORK_CENTER_MANAGE)
def revise_work_center_template(template_uid):
    try:
        result = _service().revise_notification_template(
            template_uid,
            request.get_json(silent=True) or {},
            expected_version=_expected_version(),
            actor_uid=g.current_user["id"],
        )
        return _etag(jsonify(success(result, "通知模板已更新")), result["current_version"])
    except (ValueError, LookupError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/preferences", methods=["GET"])
@require_permissions(WORK_CENTER_READ)
def get_work_center_preferences():
    result = _service().get_notification_preferences(g.current_user["id"])
    return _etag(jsonify(success(result)), result["revision"])


@bp.route("/work-center/preferences", methods=["PUT"])
@require_permissions(WORK_CENTER_OPERATE)
def replace_work_center_preferences():
    try:
        result = _service().replace_notification_preferences(
            request.get_json(silent=True) or {},
            expected_revision=_expected_version(),
            actor_uid=g.current_user["id"],
        )
        return _etag(jsonify(success(result, "通知偏好已更新")), result["revision"])
    except (ValueError, RuntimeError) as exc:
        return _error(exc)


@bp.route("/work-center/dashboard", methods=["GET"])
@require_permissions(WORK_CENTER_READ)
def get_work_center_dashboard():
    try:
        return jsonify(success(_service().dashboard(at=request.args.get("at"))))
    except ValueError as exc:
        return _error(exc)