"""接口级权限管理API"""

from __future__ import annotations

import uuid
from typing import Annotated

from fastapi import APIRouter, Depends, HTTPException, status
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.deps import get_current_user, get_db_session, is_system_admin, require_study_member, require_system_permission
from app.core.project_permissions import (
    get_api_endpoint_permissions,
    get_effective_api_endpoint_permissions,
    PrerequisitePermissionConfirmationRequired,
    replace_api_endpoint_permissions,
    get_missing_prerequisites,
)
from app.crud import member as member_crud
from app.models.api_endpoint_registry import ApiEndpointRegistry
from app.models.study import Study
from app.core.api_permissions import API_ENDPOINT_PERMISSIONS, PROJECT_PERMISSION_ROLES, OPERATION_PREREQUISITES

router = APIRouter(prefix="/api-permissions", tags=["api-permissions"])

# 项目级路由（需要 study_id，挂载到 /studies/{study_id}/api-permissions）
study_router = APIRouter(prefix="/api-permissions", tags=["api-permissions"])


async def _get_configurable_roles(db: AsyncSession, study_id: uuid.UUID) -> list[str]:
    result = await db.execute(select(Study).where(Study.id == study_id))
    study = result.scalar_one_or_none()
    active_roles = [role for role in (study.active_roles if study else []) if isinstance(role, str) and role.strip()]
    return list(dict.fromkeys([*PROJECT_PERMISSION_ROLES, *active_roles]))


@router.get(
    "/operations",
    summary="获取系统中所有权限操作",
    description="返回系统中所有权限操作及其描述和前置权限",
)
async def list_api_operations() -> dict[str, list[dict]]:
    """获取所有权限操作"""
    operations_list = [
        {
            "operation_key": key,
            "module": config["module"],
            "action": config["action"],
            "description": config["description"],
            "default_roles": config["default_roles"],
            "prerequisite_permissions": config.get("prerequisite_permissions", []),
        }
        for key, config in API_ENDPOINT_PERMISSIONS.items()
    ]

    return {"operations": operations_list}


@router.get(
    "/endpoints",
    summary="获取系统中所有已注册的API端点",
    description="返回系统中所有已注册的API端点及其元数据",
)
async def list_api_endpoints(
    db: Annotated[AsyncSession, Depends(get_db_session)],
) -> dict[str, list[dict]]:
    """获取所有已注册的API端点"""
    result = await db.execute(select(ApiEndpointRegistry))
    endpoints = result.scalars().all()

    endpoints_list = [
        {
            "endpoint_key": ep.endpoint_key,
            "method": ep.method,
            "path": ep.path,
            "module": ep.module,
            "action": ep.action,
            "description": ep.description,
            "default_roles": ep.default_roles.split(",") if ep.default_roles else [],
        }
        for ep in endpoints
    ]

    return {"endpoints": endpoints_list}


@router.get(
    "/operations/prerequisites",
    summary="获取所有权限操作的前置权限依赖",
    description="返回系统中所有权限操作及其前置权限依赖关系",
)
async def list_operation_prerequisites() -> dict[str, dict]:
    """获取所有权限操作的前置权限依赖"""
    prerequisites_map = {}
    for operation_key, prerequisites in OPERATION_PREREQUISITES.items():
        prerequisites_map[operation_key] = {
            "prerequisites": prerequisites,
            "description": API_ENDPOINT_PERMISSIONS.get(operation_key, {}).get("description", ""),
        }

    return {"prerequisites": prerequisites_map}


@router.get(
    "/{endpoint_key}/prerequisites",
    summary="获取特定操作的缺失前置权限",
    description="检查指定角色对特定操作的前置权限是否满足",
)
async def check_operation_prerequisites(
    study_id: uuid.UUID,
    endpoint_key: str,
    role: str,
    db: Annotated[AsyncSession, Depends(get_db_session)],
) -> dict:
    """检查特定操作的前置权限

    返回格式:
    {
        "endpoint_key": "subjects:create",
        "role": "CRA",
        "has_main_permission": true,
        "prerequisites": ["sites:read"],
        "missing_prerequisites": [],
        "can_perform": true
    }
    """
    from app.core.project_permissions import role_has_api_permission

    if role == "ADMIN":
        return {
            "endpoint_key": endpoint_key,
            "role": role,
            "has_main_permission": True,
            "prerequisites": OPERATION_PREREQUISITES.get(endpoint_key, []),
            "missing_prerequisites": [],
            "can_perform": True,
        }

    has_main = await role_has_api_permission(
        db, study_id, role, endpoint_key, check_prerequisites=False
    )
    missing = await get_missing_prerequisites(db, study_id, role, endpoint_key)

    return {
        "endpoint_key": endpoint_key,
        "role": role,
        "has_main_permission": has_main,
        "prerequisites": OPERATION_PREREQUISITES.get(endpoint_key, []),
        "missing_prerequisites": missing,
        "can_perform": has_main and len(missing) == 0,
    }


@study_router.get(
    "/me",
    summary="获取当前用户在项目内的有效接口权限",
    description="返回当前用户项目角色对应的有效权限，用于前端菜单和路由判断",
    response_model=None,
)
async def get_my_study_api_permissions(
    study_id: uuid.UUID,
    _=Depends(require_study_member()),
    current_user=Depends(get_current_user),
    db: Annotated[AsyncSession, Depends(get_db_session)] = None,
):
    """获取当前用户当前项目角色的有效权限。"""
    if is_system_admin(current_user):
        return {
            "ADMIN": {
                endpoint_key: {"allowed": True}
                for endpoint_key in API_ENDPOINT_PERMISSIONS.keys()
            }
        }

    membership = await member_crud.get_member(db, study_id, current_user.id)
    role = membership.role_in_study if membership and membership.is_active else ""
    permissions = await get_effective_api_endpoint_permissions(db, study_id)
    role_permissions = permissions.get(role, {})
    return {
        role: {
            endpoint_key: role_permissions.get(endpoint_key, {"allowed": False})
            for endpoint_key in API_ENDPOINT_PERMISSIONS.keys()
        }
    }


@study_router.get(
    "",
    summary="获取项目的接口级权限矩阵",
    description="返回项目中各角色对API端点的权限配置",
    response_model=None,
)
async def get_study_api_permissions(
    study_id: uuid.UUID,
    _=Depends(require_system_permission("system:permissions:project_config")),
    db: Annotated[AsyncSession, Depends(get_db_session)] = None,
):
    """获取项目的接口级权限矩阵

    返回格式:
    {
        "role": {
            "endpoint_key": {
                "allowed": true/false
            }
        }
    }
    """
    permissions = await get_api_endpoint_permissions(db, study_id)

    # 构建返回格式（get_api_endpoint_permissions 已返回 {role: {key: {"allowed": bool}}}）
    result: dict[str, dict[str, dict[str, bool]]] = {}
    for role in await _get_configurable_roles(db, study_id):
        if role == "ADMIN":
            continue
        result[role] = {}
        for endpoint_key in API_ENDPOINT_PERMISSIONS.keys():
            perm = permissions.get(role, {}).get(endpoint_key, {"allowed": False})
            # perm 已经是 {"allowed": bool}，直接使用
            allowed = perm["allowed"] if isinstance(perm, dict) else bool(perm)
            result[role][endpoint_key] = {"allowed": allowed}

    return result


@study_router.put(
    "",
    summary="更新项目的接口级权限矩阵",
    description="批量更新项目中各角色对API端点的权限配置",
    status_code=status.HTTP_200_OK,
    response_model=None,
)
async def update_study_api_permissions(
    study_id: uuid.UUID,
    payload: dict[str, dict[str, bool]],
    confirm_prerequisite_adjustments: bool = False,
    _=Depends(require_system_permission("system:permissions:project_config")),
    current_user=Depends(get_current_user),
    db: Annotated[AsyncSession, Depends(get_db_session)] = None,
):
    """更新项目的接口级权限矩阵

    请求体格式:
    {
        "role": {
            "endpoint_key": true/false
        }
    }
    """
    # 验证输入
    configurable_roles = set(await _get_configurable_roles(db, study_id))
    for role in payload.keys():
        if role == "ADMIN":
            continue
        if role not in configurable_roles:
            raise ValueError(f"无效的角色: {role}")
        if role == "PM" and not is_system_admin(current_user):
            raise HTTPException(
                status_code=status.HTTP_403_FORBIDDEN,
                detail="仅系统管理员可修改项目负责人权限",
            )

    # 替换权限配置
    try:
        await replace_api_endpoint_permissions(
            db,
            study_id,
            payload,
            confirm_prerequisite_adjustments=confirm_prerequisite_adjustments,
        )
    except PrerequisitePermissionConfirmationRequired as exc:
        raise HTTPException(
            status_code=status.HTTP_409_CONFLICT,
            detail={
                "code": "PREREQUISITE_PERMISSION_CONFIRMATION_REQUIRED",
                "message": "需要确认前置权限调整",
                "adjustments": exc.adjustments,
            },
        ) from exc

    # 返回更新后的权限矩阵
    permissions = await get_api_endpoint_permissions(db, study_id)

    result: dict[str, dict[str, dict[str, bool]]] = {}
    for role in await _get_configurable_roles(db, study_id):
        if role == "ADMIN":
            continue
        result[role] = {}
        for endpoint_key in API_ENDPOINT_PERMISSIONS.keys():
            perm = permissions.get(role, {}).get(endpoint_key, {"allowed": False})
            allowed = perm["allowed"] if isinstance(perm, dict) else bool(perm)
            result[role][endpoint_key] = {"allowed": allowed}

    return result