from __future__ import annotations

import re
from uuid import UUID, uuid4

from fastapi import APIRouter, Depends, HTTPException, Query, status
from sqlalchemy import delete, func
from sqlmodel import col, select
from sqlmodel.ext.asyncio.session import AsyncSession

from app.api.deps import ActorContext, get_board_or_404, require_admin_auth, require_admin_or_agent
from app.core.auth import AuthContext
from app.core.time import utcnow
from app.db import crud
from app.db.pagination import paginate
from app.db.session import get_session
from app.integrations.openclaw_gateway import GatewayConfig as GatewayClientConfig
from app.integrations.openclaw_gateway import (
    OpenClawGatewayError,
    delete_session,
    ensure_session,
    send_message,
)
from app.models.activity_events import ActivityEvent
from app.models.agents import Agent
from app.models.approvals import Approval
from app.models.board_memory import BoardMemory
from app.models.board_onboarding import BoardOnboardingSession
from app.models.boards import Board
from app.models.gateways import Gateway
from app.models.task_dependencies import TaskDependency
from app.models.task_fingerprints import TaskFingerprint
from app.models.tasks import Task
from app.schemas.boards import BoardCreate, BoardRead, BoardUpdate
from app.schemas.common import OkResponse
from app.schemas.pagination import DefaultLimitOffsetPage
from app.schemas.view_models import BoardSnapshot
from app.services.board_snapshot import build_board_snapshot

router = APIRouter(prefix="/boards", tags=["boards"])

AGENT_SESSION_PREFIX = "agent"


def _slugify(value: str) -> str:
    slug = re.sub(r"[^a-z0-9]+", "-", value.lower()).strip("-")
    return slug or uuid4().hex


def _build_session_key(agent_name: str) -> str:
    return f"{AGENT_SESSION_PREFIX}:{_slugify(agent_name)}:main"


async def _require_gateway(session: AsyncSession, gateway_id: object) -> Gateway:
    gateway = await crud.get_by_id(session, Gateway, gateway_id)
    if gateway is None:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="gateway_id is invalid",
        )
    return gateway


async def _require_gateway_for_create(
    payload: BoardCreate,
    session: AsyncSession = Depends(get_session),
) -> Gateway:
    return await _require_gateway(session, payload.gateway_id)


async def _apply_board_update(
    *,
    payload: BoardUpdate,
    session: AsyncSession,
    board: Board,
) -> Board:
    updates = payload.model_dump(exclude_unset=True)
    if "gateway_id" in updates:
        await _require_gateway(session, updates["gateway_id"])
    for key, value in updates.items():
        setattr(board, key, value)
    if updates.get("board_type") == "goal":
        # Validate only when explicitly switching to goal boards.
        if not board.objective or not board.success_metrics:
            raise HTTPException(
                status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
                detail="Goal boards require objective and success_metrics",
            )
    if not board.gateway_id:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="gateway_id is required",
        )
    board.updated_at = utcnow()
    return await crud.save(session, board)


async def _board_gateway(
    session: AsyncSession, board: Board
) -> tuple[Gateway | None, GatewayClientConfig | None]:
    if not board.gateway_id:
        return None, None
    config = await session.get(Gateway, board.gateway_id)
    if config is None:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="Board gateway_id is invalid",
        )
    if not config.main_session_key:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="Gateway main_session_key is required",
        )
    if not config.url:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="Gateway url is required",
        )
    if not config.workspace_root:
        raise HTTPException(
            status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
            detail="Gateway workspace_root is required",
        )
    return config, GatewayClientConfig(url=config.url, token=config.token)


async def _cleanup_agent_on_gateway(
    agent: Agent,
    config: Gateway,
    client_config: GatewayClientConfig,
) -> None:
    if agent.openclaw_session_id:
        await delete_session(agent.openclaw_session_id, config=client_config)
    main_session = config.main_session_key
    workspace_root = config.workspace_root
    workspace_path = f"{workspace_root.rstrip('/')}/workspace-{_slugify(agent.name)}"
    cleanup_message = (
        "Cleanup request for deleted agent.\n\n"
        f"Agent name: {agent.name}\n"
        f"Agent id: {agent.id}\n"
        f"Session key: {agent.openclaw_session_id or _build_session_key(agent.name)}\n"
        f"Workspace path: {workspace_path}\n\n"
        "Actions:\n"
        "1) Remove the workspace directory.\n"
        "2) Delete any lingering session artifacts.\n"
        "Reply NO_REPLY."
    )
    await ensure_session(main_session, config=client_config, label="Main Agent")
    await send_message(
        cleanup_message,
        session_key=main_session,
        config=client_config,
        deliver=False,
    )


@router.get("", response_model=DefaultLimitOffsetPage[BoardRead])
async def list_boards(
    gateway_id: UUID | None = Query(default=None),
    session: AsyncSession = Depends(get_session),
    actor: ActorContext = Depends(require_admin_or_agent),
) -> DefaultLimitOffsetPage[BoardRead]:
    statement = select(Board)
    if gateway_id is not None:
        statement = statement.where(col(Board.gateway_id) == gateway_id)
    statement = statement.order_by(func.lower(col(Board.name)).asc(), col(Board.created_at).desc())
    return await paginate(session, statement)


@router.post("", response_model=BoardRead)
async def create_board(
    payload: BoardCreate,
    _gateway: Gateway = Depends(_require_gateway_for_create),
    session: AsyncSession = Depends(get_session),
    auth: AuthContext = Depends(require_admin_auth),
) -> Board:
    return await crud.create(session, Board, **payload.model_dump())


@router.get("/{board_id}", response_model=BoardRead)
def get_board(
    board: Board = Depends(get_board_or_404),
    actor: ActorContext = Depends(require_admin_or_agent),
) -> Board:
    return board


@router.get("/{board_id}/snapshot", response_model=BoardSnapshot)
async def get_board_snapshot(
    board: Board = Depends(get_board_or_404),
    session: AsyncSession = Depends(get_session),
    actor: ActorContext = Depends(require_admin_or_agent),
) -> BoardSnapshot:
    if actor.actor_type == "agent" and actor.agent:
        if actor.agent.board_id and actor.agent.board_id != board.id:
            raise HTTPException(status_code=status.HTTP_403_FORBIDDEN)
    return await build_board_snapshot(session, board)


@router.patch("/{board_id}", response_model=BoardRead)
async def update_board(
    payload: BoardUpdate,
    session: AsyncSession = Depends(get_session),
    board: Board = Depends(get_board_or_404),
    auth: AuthContext = Depends(require_admin_auth),
) -> Board:
    return await _apply_board_update(payload=payload, session=session, board=board)


@router.delete("/{board_id}", response_model=OkResponse)
async def delete_board(
    session: AsyncSession = Depends(get_session),
    board: Board = Depends(get_board_or_404),
    auth: AuthContext = Depends(require_admin_auth),
) -> OkResponse:
    agents = list(await session.exec(select(Agent).where(Agent.board_id == board.id)))
    task_ids = list(await session.exec(select(Task.id).where(Task.board_id == board.id)))

    config, client_config = await _board_gateway(session, board)
    if config and client_config:
        try:
            for agent in agents:
                await _cleanup_agent_on_gateway(agent, config, client_config)
        except OpenClawGatewayError as exc:
            raise HTTPException(
                status_code=status.HTTP_502_BAD_GATEWAY,
                detail=f"Gateway cleanup failed: {exc}",
            ) from exc

    if task_ids:
        await session.execute(delete(ActivityEvent).where(col(ActivityEvent.task_id).in_(task_ids)))
    await session.execute(delete(TaskDependency).where(col(TaskDependency.board_id) == board.id))
    await session.execute(delete(TaskFingerprint).where(col(TaskFingerprint.board_id) == board.id))

    # Approvals can reference tasks and agents, so delete before both.
    await session.execute(delete(Approval).where(col(Approval.board_id) == board.id))

    await session.execute(delete(BoardMemory).where(col(BoardMemory.board_id) == board.id))
    await session.execute(
        delete(BoardOnboardingSession).where(col(BoardOnboardingSession.board_id) == board.id)
    )

    # Tasks reference agents (assigned_agent_id) and have dependents (fingerprints/dependencies), so
    # delete tasks before agents.
    await session.execute(delete(Task).where(col(Task.board_id) == board.id))

    if agents:
        agent_ids = [agent.id for agent in agents]
        await session.execute(
            delete(ActivityEvent).where(col(ActivityEvent.agent_id).in_(agent_ids))
        )
        await session.execute(delete(Agent).where(col(Agent.id).in_(agent_ids)))
    await session.delete(board)
    await session.commit()
    return OkResponse()