import uuid
import json

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

from app.core.deps import get_current_user, get_db_session, require_study_member, require_api_permission, require_study_not_locked
from app.core.decorators import register_api_endpoint
from app.crud import audit as audit_crud
from app.crud import member as member_crud
from app.crud import study as study_crud
from app.crud import user as user_crud
from app.schemas.member import StudyMemberCreate, StudyMemberRead, StudyMemberReadWithUser, StudyMemberUpdate
from app.schemas.user import UserResponse

router = APIRouter()

PROJECT_ROLE_RANK = {
    "ADMIN": 100,
    "PM": 80,
    "QA": 60,
    "PV": 50,
    "MEDICAL_REVIEW": 50,
    "CRA": 40,
    "IMP": 40,
}


async def _ensure_study_exists(db: AsyncSession, study_id: uuid.UUID):
    study = await study_crud.get(db, study_id)
    if not study:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="项目不存在")
    return study


def _role_value(user) -> str:
    return user.role.value if hasattr(user.role, "value") else str(user.role)


def _role_rank(role: str | None) -> int:
    return PROJECT_ROLE_RANK.get(role or "", 0)


async def _ensure_member_mutation_allowed(
    db: AsyncSession,
    study_id: uuid.UUID,
    current_user,
    *,
    target_member=None,
    target_role: str | None = None,
) -> None:
    if _role_value(current_user) == "ADMIN":
        return

    actor_member = await member_crud.get_member(db, study_id, current_user.id)
    actor_role = actor_member.role_in_study if actor_member else None
    actor_rank = _role_rank(actor_role)

    if target_member and target_member.user_id == current_user.id:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="不能修改自己的项目成员权限")

    if target_member:
        target_user = await user_crud.get_by_id(db, target_member.user_id)
        if _role_value(target_user) == "ADMIN":
            raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="不能修改系统管理员账号的项目权限")

    if target_member and _role_rank(target_member.role_in_study) >= actor_rank:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="只能修改下属项目角色成员")

    if target_role and _role_rank(target_role) >= actor_rank:
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="只能授予下属项目角色")


@router.post(
    "/",
    response_model=StudyMemberRead,
    status_code=status.HTTP_201_CREATED,
    dependencies=[Depends(require_api_permission("project_members:create")), Depends(require_study_not_locked())],
)
@register_api_endpoint(
    endpoint_key="project_members:create",
    module="project_members",
    action="write",
    description="添加项目成员",
    default_roles=["PM"],
)
async def add_member(
    study_id: uuid.UUID,
    member_in: StudyMemberCreate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> StudyMemberRead:
    await _ensure_study_exists(db, study_id)
    await _ensure_member_mutation_allowed(db, study_id, current_user, target_role=member_in.role_in_study)
    existing = await member_crud.get_member(db, study_id, member_in.user_id)
    if existing:
        await _ensure_member_mutation_allowed(
            db,
            study_id,
            current_user,
            target_member=existing,
            target_role=member_in.role_in_study,
        )
        if not existing.is_active:
            updated = await member_crud.update_member(
                db,
                existing,
                StudyMemberUpdate(is_active=True, role_in_study=member_in.role_in_study),
            )
            await audit_crud.log_action(
                db,
                study_id=study_id,
                entity_type="study_member",
                entity_id=updated.id,
                action="PROJECT_MEMBER_UPDATED",
                detail=json.dumps({
                    "targetName": str(updated.user_id),
                    "before": {"is_active": existing.is_active, "role_in_study": existing.role_in_study},
                    "after": {"is_active": updated.is_active, "role_in_study": updated.role_in_study},
                }, ensure_ascii=False),
                operator_id=current_user.id,
                operator_role=current_user.role,
            )
            return updated
        raise HTTPException(status_code=status.HTTP_409_CONFLICT, detail="成员已存在")
    member = await member_crud.add_member(db, study_id, member_in)
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="study_member",
        entity_id=member.id,
        action="PROJECT_MEMBER_ADDED",
        detail=json.dumps({"targetName": str(member.user_id), "after": {"role_in_study": member.role_in_study, "is_active": member.is_active}}, ensure_ascii=False),
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return member


@router.get(
    "/",
    response_model=list[StudyMemberReadWithUser],
    dependencies=[Depends(require_api_permission("project_members:list"))],
)
@register_api_endpoint(
    endpoint_key="project_members:list",
    module="project_members",
    action="read",
    description="查询项目成员列表",
    default_roles=["PM"],
)
async def list_members(
    study_id: uuid.UUID,
    skip: int = 0,
    limit: int = 100,
    include_inactive: bool = False,
    db: AsyncSession = Depends(get_db_session),
) -> list[StudyMemberReadWithUser]:
    await _ensure_study_exists(db, study_id)
    members = await member_crud.list_members(db, study_id, skip=skip, limit=limit)
    user_ids = {m.user_id for m in members}
    users_map = await user_crud.get_users_by_ids(db, user_ids)
    result: list[StudyMemberReadWithUser] = []
    for m in members:
        user = users_map.get(m.user_id)
        if not include_inactive:
            # 仅返回项目内启用的成员 + 账号启用的用户
            if not m.is_active:
                continue
            if not user or not user.is_active:
                continue
        result.append(
            StudyMemberReadWithUser(
                id=m.id,
                study_id=m.study_id,
                user_id=m.user_id,
                role_in_study=m.role_in_study,
                is_active=m.is_active,
                added_at=m.added_at,
                user=UserResponse.model_validate(user) if user else None,
            )
        )
    return result


@router.get(
    "/candidates",
    response_model=list[UserResponse],
    dependencies=[Depends(require_api_permission("project_members:candidates"))],
)
@register_api_endpoint(
    endpoint_key="project_members:candidates",
    module="project_members",
    action="read",
    description="查询项目成员候选人",
    default_roles=["PM"],
)
async def list_member_candidates(
    study_id: uuid.UUID,
    skip: int = 0,
    limit: int = 500,
    db: AsyncSession = Depends(get_db_session),
) -> list[UserResponse]:
    await _ensure_study_exists(db, study_id)
    users = await user_crud.list_active_member_candidates_for_study(db, study_id, skip=skip, limit=limit)
    return [UserResponse.model_validate(user) for user in users]


@router.patch(
    "/{member_id}",
    response_model=StudyMemberRead,
    dependencies=[Depends(require_api_permission("project_members:update")), Depends(require_study_not_locked())],
)
@register_api_endpoint(
    endpoint_key="project_members:update",
    module="project_members",
    action="write",
    description="更新项目成员",
    default_roles=["PM"],
)
async def update_member(
    study_id: uuid.UUID,
    member_id: uuid.UUID,
    member_in: StudyMemberUpdate,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> StudyMemberRead:
    await _ensure_study_exists(db, study_id)
    member = await member_crud.get_member_by_id(db, member_id)
    if not member or member.study_id != study_id:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="成员不存在")
    await _ensure_member_mutation_allowed(
        db,
        study_id,
        current_user,
        target_member=member,
        target_role=member_in.role_in_study,
    )
    before_data = {"role_in_study": member.role_in_study, "is_active": member.is_active}
    updated = await member_crud.update_member(db, member, member_in)
    after_data = {"role_in_study": updated.role_in_study, "is_active": updated.is_active}
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="study_member",
        entity_id=updated.id,
        action="PROJECT_MEMBER_UPDATED",
        detail=json.dumps({"targetName": str(updated.user_id), "before": before_data, "after": after_data}, ensure_ascii=False),
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return updated


@router.delete(
    "/{member_id}",
    response_model=StudyMemberRead,
    dependencies=[Depends(require_api_permission("project_members:delete")), Depends(require_study_not_locked())],
)
@register_api_endpoint(
    endpoint_key="project_members:delete",
    module="project_members",
    action="write",
    description="删除项目成员",
    default_roles=["PM"],
)
async def remove_member(
    study_id: uuid.UUID,
    member_id: uuid.UUID,
    db: AsyncSession = Depends(get_db_session),
    current_user=Depends(get_current_user),
) -> StudyMemberRead:
    await _ensure_study_exists(db, study_id)
    member = await member_crud.get_member_by_id(db, member_id)
    if not member or member.study_id != study_id:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="成员不存在")
    target_user = await user_crud.get_by_id(db, member.user_id)
    if target_user and _role_value(target_user) == "ADMIN":
        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="系统管理员不可从项目中移除")
    await _ensure_member_mutation_allowed(db, study_id, current_user, target_member=member)
    before_data = {"role_in_study": member.role_in_study, "is_active": member.is_active}
    removed = await member_crud.remove_member(db, member)
    await audit_crud.log_action(
        db,
        study_id=study_id,
        entity_type="study_member",
        entity_id=removed.id,
        action="PROJECT_MEMBER_REMOVED",
        detail=json.dumps({"targetName": str(removed.user_id), "before": before_data, "after": {"is_active": removed.is_active}}, ensure_ascii=False),
        operator_id=current_user.id,
        operator_role=current_user.role,
    )
    return removed