from __future__ import annotations

import uuid

from sqlalchemy import delete, select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.api_endpoint_permission import ApiEndpointPermission
from app.core.api_permissions import API_ENDPOINT_PERMISSIONS, OPERATION_PREREQUISITES
from app.core.permission_cache import get_permission_cache


async def role_has_api_permission(
    db: AsyncSession,
    study_id: uuid.UUID,
    role: str | None,
    endpoint_key: str,
    check_prerequisites: bool = True,
) -> bool:
    """检查角色是否有权访问特定接口"""
    if role == "ADMIN":
        return True

    result = await db.execute(
        select(ApiEndpointPermission).where(
            ApiEndpointPermission.study_id == study_id,
            ApiEndpointPermission.role == role,
            ApiEndpointPermission.endpoint_key == endpoint_key,
        )
    )
    perm = result.scalar_one_or_none()
    if perm is None:
        return False

    if not perm.allowed:
        return False

    if check_prerequisites:
        prerequisites = OPERATION_PREREQUISITES.get(endpoint_key, [])
        for prereq_endpoint in prerequisites:
            has_prereq = await role_has_api_permission(
                db, study_id, role, prereq_endpoint, check_prerequisites=False
            )
            if not has_prereq:
                return False

    return True


async def get_missing_prerequisites(
    db: AsyncSession,
    study_id: uuid.UUID,
    role: str | None,
    endpoint_key: str,
) -> list[str]:
    """获取缺失的前置权限列表"""
    if role == "ADMIN":
        return []

    missing = []
    prerequisites = OPERATION_PREREQUISITES.get(endpoint_key, [])
    for prereq_endpoint in prerequisites:
        has_prereq = await role_has_api_permission(
            db, study_id, role, prereq_endpoint, check_prerequisites=False
        )
        if not has_prereq:
            missing.append(prereq_endpoint)

    return missing


async def get_api_endpoint_permissions(
    db: AsyncSession,
    study_id: uuid.UUID,
) -> dict[str, dict[str, dict[str, bool]]]:
    """获取项目的接口级权限矩阵

    返回格式: {role: {endpoint_key: {allowed: bool}}}
    """
    result = await db.execute(
        select(ApiEndpointPermission).where(
            ApiEndpointPermission.study_id == study_id,
        )
    )
    rows = result.scalars().all()

    roles = ["PM", "CRA", "PV", "MEDICAL_REVIEW", "IMP", "QA"]
    matrix: dict[str, dict[str, dict[str, bool]]] = {}
    for role in roles:
        matrix[role] = {}
        for endpoint_key, config in API_ENDPOINT_PERMISSIONS.items():
            default_allowed = role in config.get("default_roles", [])
            matrix[role][endpoint_key] = {"allowed": default_allowed}

    for row in rows:
        if row.role not in matrix:
            matrix[row.role] = {}
        matrix[row.role][row.endpoint_key] = {"allowed": row.allowed}

    return matrix


async def replace_api_endpoint_permissions(
    db: AsyncSession,
    study_id: uuid.UUID,
    payload: dict[str, dict[str, bool]],
) -> dict[str, dict[str, dict[str, bool]]]:
    """替换项目的接口级权限矩阵"""
    await db.execute(
        delete(ApiEndpointPermission).where(
            ApiEndpointPermission.study_id == study_id,
        )
    )

    for role, endpoints in payload.items():
        if role == "ADMIN":
            continue
        for endpoint_key, allowed in endpoints.items():
            if endpoint_key not in API_ENDPOINT_PERMISSIONS:
                continue
            db.add(
                ApiEndpointPermission(
                    study_id=study_id,
                    role=role,
                    endpoint_key=endpoint_key,
                    allowed=allowed,
                )
            )

    await db.commit()

    cache = get_permission_cache()
    cache.invalidate_project_permissions(study_id)
    cache.invalidate_all_member_roles(study_id)

    return await get_api_endpoint_permissions(db, study_id)