"""Engagement CRUD endpoints (flat, sprint 0)."""

from __future__ import annotations

from uuid import UUID

from flask import Blueprint, abort, jsonify
from flask.typing import ResponseReturnValue
from sqlalchemy import select

from mimic.api._helpers import (
    audit_write,
    current_user_id,
    is_rt_lead,
    jsonify_model,
    parse_body,
    parse_uuid,
)
from mimic.db.models import Engagement, EngagementMember
from mimic.db.types import EngagementStatus
from mimic.extensions import db
from mimic.rbac import Permission, require_perm
from mimic.schemas import EngagementCreate, EngagementRead, EngagementUpdate

bp = Blueprint("engagements", __name__)


def _engagement_or_404(eid: str) -> Engagement:
    engagement = db.session.get(Engagement, parse_uuid(eid))
    if engagement is None:
        abort(404)
    # MA6: RT operators may only see engagements they're assigned to.
    if not is_rt_lead():
        user_id = current_user_id()
        if user_id is None or not _is_member(engagement.id, user_id):
            abort(404)
    return engagement


def _is_member(engagement_id: UUID, user_id: UUID) -> bool:
    stmt = select(EngagementMember).where(
        EngagementMember.engagement_id == engagement_id,
        EngagementMember.user_id == user_id,
    )
    return db.session.execute(stmt).scalar_one_or_none() is not None


@bp.get("")
@require_perm(Permission.ENGAGEMENT_READ)
def list_engagements() -> ResponseReturnValue:
    stmt = select(Engagement).order_by(Engagement.created_at.desc())
    # MA6: RT operators see only their assignments.
    if not is_rt_lead():
        user_id = current_user_id()
        if user_id is None:
            return jsonify([])
        stmt = stmt.join(
            EngagementMember,
            EngagementMember.engagement_id == Engagement.id,
        ).where(EngagementMember.user_id == user_id)
    rows = db.session.execute(stmt).scalars().all()
    return jsonify([EngagementRead.model_validate(row).model_dump(mode="json") for row in rows])


@bp.post("")
@require_perm(Permission.ENGAGEMENT_CREATE)
def create_engagement() -> ResponseReturnValue:
    payload = parse_body(EngagementCreate)
    engagement = Engagement(
        client_name=payload.client_name,
        description=payload.description,
        c2_type=payload.c2_type,
        start_date=payload.start_date,
        end_date=payload.end_date,
        status=EngagementStatus.DRAFT,
        created_by_id=current_user_id(),
    )
    db.session.add(engagement)
    db.session.commit()
    audit_write(
        action="engagement.create",
        resource_type="engagement",
        resource_id=engagement.id,
        metadata={"client_name": engagement.client_name},
    )
    return jsonify_model(EngagementRead.model_validate(engagement), status=201)


@bp.get("/<eid>")
@require_perm(Permission.ENGAGEMENT_READ)
def get_engagement(eid: str) -> ResponseReturnValue:
    engagement = _engagement_or_404(eid)
    return jsonify_model(EngagementRead.model_validate(engagement))


@bp.put("/<eid>")
@require_perm(Permission.ENGAGEMENT_UPDATE)
def update_engagement(eid: str) -> ResponseReturnValue:
    engagement = _engagement_or_404(eid)
    payload = parse_body(EngagementUpdate)
    changes = payload.model_dump(exclude_unset=True)
    for field, value in changes.items():
        setattr(engagement, field, value)
    db.session.commit()
    audit_write(
        action="engagement.update",
        resource_type="engagement",
        resource_id=engagement.id,
        metadata={"fields": sorted(changes.keys())},
    )
    return jsonify_model(EngagementRead.model_validate(engagement))


@bp.delete("/<eid>")
@require_perm(Permission.ENGAGEMENT_DELETE)
def delete_engagement(eid: str) -> ResponseReturnValue:
    engagement = _engagement_or_404(eid)
    engagement.status = EngagementStatus.ARCHIVED
    db.session.commit()
    audit_write(
        action="engagement.archive",
        resource_type="engagement",
        resource_id=engagement.id,
    )
    return "", 204