"""
Brief API
项目 Brief 文档的 CRUD
"""
from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select
from sqlalchemy.orm import selectinload

from app.database import get_db
from app.models.user import User, UserRole
from app.models.project import Project
from app.models.brief import Brief
from app.models.organization import Brand, Agency
from app.api.deps import get_current_user
from app.schemas.brief import (
    BriefCreateRequest,
    BriefUpdateRequest,
    BriefResponse,
)
from app.services.auth import generate_id

router = APIRouter(prefix="/projects/{project_id}/brief", tags=["Brief"])


async def _get_project_with_permission(
    project_id: str,
    current_user: User,
    db: AsyncSession,
    require_write: bool = False,
) -> Project:
    """获取项目并检查权限"""
    result = await db.execute(
        select(Project)
        .options(selectinload(Project.brand), selectinload(Project.agencies))
        .where(Project.id == project_id)
    )
    project = result.scalar_one_or_none()
    if not project:
        raise HTTPException(status_code=404, detail="项目不存在")

    if current_user.role == UserRole.BRAND:
        brand_result = await db.execute(
            select(Brand).where(Brand.user_id == current_user.id)
        )
        brand = brand_result.scalar_one_or_none()
        if not brand or project.brand_id != brand.id:
            raise HTTPException(status_code=403, detail="无权访问此项目")
    elif current_user.role == UserRole.AGENCY:
        if require_write:
            raise HTTPException(status_code=403, detail="代理商无权修改 Brief")
        agency_result = await db.execute(
            select(Agency).where(Agency.user_id == current_user.id)
        )
        agency = agency_result.scalar_one_or_none()
        if not agency or agency not in project.agencies:
            raise HTTPException(status_code=403, detail="无权访问此项目")
    elif current_user.role == UserRole.CREATOR:
        # 达人可以查看 Brief（只读）
        if require_write:
            raise HTTPException(status_code=403, detail="达人无权修改 Brief")
    else:
        raise HTTPException(status_code=403, detail="无权访问")

    return project


def _brief_to_response(brief: Brief) -> BriefResponse:
    """转换 Brief 为响应"""
    return BriefResponse(
        id=brief.id,
        project_id=brief.project_id,
        project_name=brief.project.name if brief.project else None,
        file_url=brief.file_url,
        file_name=brief.file_name,
        selling_points=brief.selling_points,
        blacklist_words=brief.blacklist_words,
        competitors=brief.competitors,
        brand_tone=brief.brand_tone,
        min_duration=brief.min_duration,
        max_duration=brief.max_duration,
        other_requirements=brief.other_requirements,
        attachments=brief.attachments,
        created_at=brief.created_at,
        updated_at=brief.updated_at,
    )


@router.get("", response_model=BriefResponse)
async def get_brief(
    project_id: str,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    """获取项目 Brief"""
    await _get_project_with_permission(project_id, current_user, db)

    result = await db.execute(
        select(Brief)
        .options(selectinload(Brief.project))
        .where(Brief.project_id == project_id)
    )
    brief = result.scalar_one_or_none()
    if not brief:
        raise HTTPException(status_code=404, detail="Brief 不存在")

    return _brief_to_response(brief)


@router.post("", response_model=BriefResponse, status_code=status.HTTP_201_CREATED)
async def create_brief(
    project_id: str,
    request: BriefCreateRequest,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    """创建项目 Brief（品牌方操作）"""
    await _get_project_with_permission(project_id, current_user, db, require_write=True)

    # 检查是否已存在
    existing = await db.execute(
        select(Brief).where(Brief.project_id == project_id)
    )
    if existing.scalar_one_or_none():
        raise HTTPException(status_code=400, detail="该项目已有 Brief，请使用更新接口")

    brief = Brief(
        id=generate_id("BF"),
        project_id=project_id,
        file_url=request.file_url,
        file_name=request.file_name,
        selling_points=request.selling_points,
        blacklist_words=request.blacklist_words,
        competitors=request.competitors,
        brand_tone=request.brand_tone,
        min_duration=request.min_duration,
        max_duration=request.max_duration,
        other_requirements=request.other_requirements,
        attachments=request.attachments,
    )
    db.add(brief)
    await db.flush()

    # 重新加载
    result = await db.execute(
        select(Brief)
        .options(selectinload(Brief.project))
        .where(Brief.id == brief.id)
    )
    brief = result.scalar_one()

    return _brief_to_response(brief)


@router.put("", response_model=BriefResponse)
async def update_brief(
    project_id: str,
    request: BriefUpdateRequest,
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    """更新项目 Brief（品牌方操作）"""
    await _get_project_with_permission(project_id, current_user, db, require_write=True)

    result = await db.execute(
        select(Brief)
        .options(selectinload(Brief.project))
        .where(Brief.project_id == project_id)
    )
    brief = result.scalar_one_or_none()
    if not brief:
        raise HTTPException(status_code=404, detail="Brief 不存在")

    # 更新字段
    update_fields = request.model_dump(exclude_unset=True)
    for field, value in update_fields.items():
        setattr(brief, field, value)

    await db.flush()
    await db.refresh(brief)

    return _brief_to_response(brief)