from __future__ import annotations

from datetime import datetime
from typing import List, Optional

from fastapi import APIRouter, HTTPException
from fastapi.responses import Response
from pydantic import BaseModel

from app.db import get_pool

router = APIRouter(tags=["models"])


async def _bump_all_domain_versions(conn) -> None:
    """api_key 有变动时，所有域名的版本号 +1，让客户端感知到数据变化。"""
    await conn.execute(
        "UPDATE domain_version SET version = version + 1, updated_at = NOW()"
    )
    await conn.execute(
        "UPDATE price_snapshot_version SET version = GREATEST(version + 1, 1), updated_at = NOW() WHERE id = 1"
    )


class ModelIn(BaseModel):
    name: str
    url: str
    api_key_id: Optional[int] = None
    group_id: Optional[int] = None


class ModelUpdate(BaseModel):
    name: Optional[str] = None
    url: Optional[str] = None
    api_key_id: Optional[int] = None
    group_id: Optional[int] = None


class ModelOut(BaseModel):
    id: int
    name: str
    url: str
    api_key_id: Optional[int]
    api_key_name: Optional[str] = None
    group_id: Optional[int] = None
    group_name: Optional[str] = None
    created_at: datetime


@router.get("/models", response_model=List[ModelOut])
async def list_models() -> List[ModelOut]:
    pool = get_pool()
    async with pool.acquire() as conn:
        rows = await conn.fetch(
            """
            SELECT m.id, m.name, m.url, m.api_key_id, m.group_id, m.created_at,
                   k.name AS api_key_name, g.name AS group_name
            FROM models m
            LEFT JOIN api_keys k ON k.id = m.api_key_id
            LEFT JOIN model_groups g ON g.id = m.group_id
            ORDER BY m.created_at DESC
            """
        )
    return [ModelOut(**dict(r)) for r in rows]


@router.post("/models", response_model=ModelOut, status_code=201)
async def create_model(body: ModelIn) -> ModelOut:
    pool = get_pool()
    async with pool.acquire() as conn:
        try:
            row = await conn.fetchrow(
                """
                INSERT INTO models (name, url, api_key_id, group_id) VALUES ($1, $2, $3, $4)
                RETURNING id, name, url, api_key_id, group_id, created_at
                """,
                body.name, body.url, body.api_key_id, body.group_id,
            )
            api_key_name = None
            if row["api_key_id"]:
                k = await conn.fetchrow("SELECT name FROM api_keys WHERE id = $1", row["api_key_id"])
                api_key_name = k["name"] if k else None
            group_name = None
            if row["group_id"]:
                g = await conn.fetchrow("SELECT name FROM model_groups WHERE id = $1", row["group_id"])
                group_name = g["name"] if g else None
        except Exception:
            raise HTTPException(status_code=409, detail="该 URL 已存在")
    return ModelOut(**dict(row), api_key_name=api_key_name, group_name=group_name)


@router.put("/models/{model_id}", response_model=ModelOut)
async def update_model(model_id: int, body: ModelUpdate) -> ModelOut:
    pool = get_pool()
    async with pool.acquire() as conn:
        existing = await conn.fetchrow(
            "SELECT id, name, url, api_key_id, group_id, created_at FROM models WHERE id = $1",
            model_id,
        )
        if existing is None:
            raise HTTPException(status_code=404, detail="模型不存在")
        new_name      = body.name       if body.name       is not None else existing["name"]
        new_url       = body.url        if body.url        is not None else existing["url"]
        new_api_key_id = body.api_key_id if body.api_key_id is not None else existing["api_key_id"]
        new_group_id  = body.group_id   if body.group_id   is not None else existing["group_id"]
        api_key_changed = new_api_key_id != existing["api_key_id"]
        try:
            async with conn.transaction():
                row = await conn.fetchrow(
                    """
                    UPDATE models SET name = $1, url = $2, api_key_id = $3, group_id = $4
                    WHERE id = $5
                    RETURNING id, name, url, api_key_id, group_id, created_at
                    """,
                    new_name, new_url, new_api_key_id, new_group_id, model_id,
                )
                if api_key_changed:
                    await _bump_all_domain_versions(conn)
                api_key_name = None
                if row["api_key_id"]:
                    k = await conn.fetchrow("SELECT name FROM api_keys WHERE id = $1", row["api_key_id"])
                    api_key_name = k["name"] if k else None
                group_name = None
                if row["group_id"]:
                    g = await conn.fetchrow("SELECT name FROM model_groups WHERE id = $1", row["group_id"])
                    group_name = g["name"] if g else None
        except HTTPException:
            raise
        except Exception:
            raise HTTPException(status_code=409, detail="该 URL 已存在")
    return ModelOut(**dict(row), api_key_name=api_key_name, group_name=group_name)


@router.delete("/models/{model_id}", status_code=204, response_model=None)
async def delete_model(model_id: int) -> Response:
    pool = get_pool()
    async with pool.acquire() as conn:
        result = await conn.execute("DELETE FROM models WHERE id = $1", model_id)
    if result == "DELETE 0":
        raise HTTPException(status_code=404, detail="模型不存在")
    return Response(status_code=204)