"""CRUD API for a user's personal custom prompts (常用提示词).

Prompts are bound to the requesting user (not stored in the browser), so they
follow the account across devices/sessions.
"""

from __future__ import annotations

import logging
from datetime import datetime
from uuid import uuid4

from fastapi import APIRouter, HTTPException, Request
from pydantic import BaseModel, Field

from deerflow.runtime.user_context import get_effective_user_id

logger = logging.getLogger(__name__)
router = APIRouter(prefix="/api/user-prompts", tags=["user-prompts"])


class UserPromptResponse(BaseModel):
    id: str
    title: str = ""
    content: str
    sort_order: int = 0
    # Optional single-agent association. NULL = global (shown for every agent).
    agent_id: str | None = None
    created_at: datetime | str | None = None
    updated_at: datetime | str | None = None


class UserPromptsListResponse(BaseModel):
    prompts: list[UserPromptResponse]


class UserPromptCreateRequest(BaseModel):
    title: str = Field(default="", max_length=255)
    content: str = Field(..., min_length=1)
    sort_order: int = Field(default=0)
    agent_id: str | None = Field(default=None, max_length=64)


class UserPromptUpdateRequest(BaseModel):
    title: str | None = Field(default=None, max_length=255)
    content: str | None = Field(default=None, min_length=1)
    sort_order: int | None = None
    # Sent on every save; an empty string / null clears the association. Use a
    # sentinel so "field omitted" (don't touch) differs from "set to null".
    agent_id: str | None = Field(default=None, max_length=64)


def _current_user_id(request: Request) -> str:
    user = getattr(request.state, "user", None)
    if user is not None:
        return str(user.id)
    return get_effective_user_id()


def _get_store(request: Request):
    store = getattr(request.app.state, "user_prompt_store", None)
    if store is None:
        raise HTTPException(status_code=503, detail="User prompt store not available")
    return store


@router.get("", response_model=UserPromptsListResponse)
async def list_user_prompts(request: Request) -> UserPromptsListResponse:
    store = _get_store(request)
    user_id = _current_user_id(request)
    rows = await store.list_for_user(user_id)
    return UserPromptsListResponse(prompts=[UserPromptResponse(**r) for r in rows])


@router.post("", response_model=UserPromptResponse, status_code=201)
async def create_user_prompt(request: Request, body: UserPromptCreateRequest) -> UserPromptResponse:
    store = _get_store(request)
    user_id = _current_user_id(request)
    row = await store.create(
        user_id,
        {
            "id": uuid4().hex,
            "title": (body.title or "").strip(),
            "content": body.content,
            "sort_order": body.sort_order,
            "agent_id": (body.agent_id or "").strip() or None,
        },
    )
    return UserPromptResponse(**row)


@router.put("/{prompt_id}", response_model=UserPromptResponse)
async def update_user_prompt(request: Request, prompt_id: str, body: UserPromptUpdateRequest) -> UserPromptResponse:
    store = _get_store(request)
    user_id = _current_user_id(request)
    data: dict = {}
    if body.title is not None:
        data["title"] = body.title.strip()
    if body.content is not None:
        data["content"] = body.content
    if body.sort_order is not None:
        data["sort_order"] = body.sort_order
    # ``agent_id`` is nullable: only act when the caller actually sent the field
    # (``model_fields_set``), so an explicit null clears the association while an
    # omitted field leaves it untouched.
    if "agent_id" in body.model_fields_set:
        data["agent_id"] = (body.agent_id or "").strip() or None
    row = await store.update(prompt_id, user_id, data)
    if row is None:
        raise HTTPException(status_code=404, detail="Prompt not found")
    return UserPromptResponse(**row)


@router.delete("/{prompt_id}", status_code=204)
async def delete_user_prompt(request: Request, prompt_id: str) -> None:
    store = _get_store(request)
    user_id = _current_user_id(request)
    deleted = await store.delete(prompt_id, user_id)
    if not deleted:
        raise HTTPException(status_code=404, detail="Prompt not found")