"""API /api/trainings — enqueue, list, get, artifacts."""
from __future__ import annotations

import json
import uuid
from typing import Optional

from fastapi import APIRouter, Depends, HTTPException, Query

from core import db, minio_client, redis_client, api_client
from core.auth import require_auth

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


def _row(r) -> Optional[dict]:
    if r is None:
        return None
    d = dict(r)
    for k in ("queued_at", "started_at", "finished_at"):
        if d.get(k) is not None and hasattr(d[k], "isoformat"):
            d[k] = d[k].isoformat()
    return d


@router.get("")
async def list_trainings(
    model_id: Optional[str] = Query(None),
    status: Optional[str] = Query(None),
    limit: int = Query(100, le=500),
    user=Depends(require_auth),
):
    where = []
    args: list = []
    if model_id:
        args.append(uuid.UUID(model_id))
        where.append(f"model_id = ${len(args)}")
    if status:
        args.append(status)
        where.append(f"status = ${len(args)}")
    sql = "SELECT * FROM trainings"
    if where:
        sql += " WHERE " + " AND ".join(where)
    args.append(limit)
    sql += f" ORDER BY queued_at DESC LIMIT ${len(args)}"
    rows = await db.fetch(sql, *args)
    return {"count": len(rows), "trainings": [_row(r) for r in rows]}


@router.post("", status_code=202)
async def enqueue_training(body: dict, user=Depends(require_auth)):
    for k in ("model_id", "version", "patch", "dataset_id"):
        if not body.get(k):
            raise HTTPException(400, f"missing field: {k}")

    model_row = await db.fetchrow("SELECT * FROM models WHERE id = $1", uuid.UUID(body["model_id"]))
    if not model_row:
        raise HTTPException(404, "model not found")

    ds_row = await db.fetchrow("SELECT id FROM datasets WHERE id = $1", uuid.UUID(body["dataset_id"]))
    if not ds_row:
        raise HTTPException(404, "dataset not found")

    try:
        training_row = await db.fetchrow(
            """
            INSERT INTO trainings (model_id, version, patch, dataset_id, started_by, status)
            VALUES ($1,$2,$3,$4,$5,'queued')
            RETURNING *
            """,
            uuid.UUID(body["model_id"]),
            body["version"],
            body["patch"],
            uuid.UUID(body["dataset_id"]),
            user.get("username") or "unknown",
        )
    except Exception as e:
        raise HTTPException(409, f"training already exists or invalid: {e}")

    training_id = str(training_row["id"])

    # crea job lato api-service (cross-service registry)
    try:
        await api_client.create_job(
            "train",
            created_by=user.get("username") or "unknown",
            payload={
                "training_id": training_id,
                "model_id": body["model_id"],
                "version": body["version"],
                "patch": body["patch"],
                "dataset_id": body["dataset_id"],
            },
        )
    except Exception as e:
        # non-fatale: il worker locale può comunque procedere; logghiamo e continuiamo
        import logging
        logging.warning("create_job failed: %s", e)

    # enqueue in Redis (il worker locale lo raccoglie)
    await redis_client.client().lpush("ml:queue:train", training_id)
    await redis_client.client().hset(
        f"ml:train:{training_id}",
        mapping={"status": "queued", "progress": "0", "message": "queued"},
    )
    await redis_client.client().expire(f"ml:train:{training_id}", 48 * 3600)

    return _row(training_row)


@router.get("/{training_id}")
async def get_training(training_id: str, user=Depends(require_auth)):
    row = await db.fetchrow("SELECT * FROM trainings WHERE id = $1", uuid.UUID(training_id))
    if not row:
        raise HTTPException(404, "not found")
    return _row(row)


@router.get("/{training_id}/artifacts")
async def list_artifacts(training_id: str, user=Depends(require_auth)):
    row = await db.fetchrow(
        "SELECT artifacts_prefix FROM trainings WHERE id = $1", uuid.UUID(training_id)
    )
    if not row or not row["artifacts_prefix"]:
        raise HTTPException(404, "no artifacts")
    objs = minio_client.list_prefix(row["artifacts_prefix"] + "/")
    for o in objs:
        o["url"] = minio_client.presigned_get(o["name"], 3600)
    return objs