"""Experiment API（Phase 4）：列表 / 详情 / 一键复跑。"""

from __future__ import annotations

import json
from datetime import datetime

from fastapi import APIRouter, BackgroundTasks, HTTPException

from app.api.deps import DbSession, ExperimentRepoDep, JobRepoDep
from app.api.jobs import _bg_factories
from app.application.services.job_executor import execute_job, new_id
from app.domain.entities.research import (
    ExperimentRecord,
    JobRecord,
    JobStatus,
)

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


def _experiment_meta(exp: ExperimentRecord) -> dict:
    spec = json.loads(exp.spec_json)
    return {
        "id": exp.id,
        "kind": exp.kind,
        "factors": [f["name"] for f in spec.get("factors", [])],
        "period": spec.get("period"),
        "rebalance": spec.get("rebalance"),
        "top_n": spec.get("selection", {}).get("top_n"),
        "summary_text": exp.summary_text,
        "code_version": exp.code_version,
        "created_at": exp.created_at,
    }


def _experiment_full(exp: ExperimentRecord) -> dict:
    from app.api.jobs import _decode_result

    return {
        **_experiment_meta(exp),
        "spec": json.loads(exp.spec_json),
        "result": _decode_result(exp.kind, exp.result_json),
    }


@router.get("", summary="Experiment 列表")
def list_experiments(experiment_repo: ExperimentRepoDep) -> list[dict]:
    return [_experiment_meta(e) for e in experiment_repo.list_recent(limit=50)]


@router.get("/{experiment_id}", summary="Experiment 详情（含完整结果）")
def get_experiment(experiment_id: str, experiment_repo: ExperimentRepoDep) -> dict:
    exp = experiment_repo.get(experiment_id)
    if exp is None:
        raise HTTPException(status_code=404, detail=f"Experiment {experiment_id} 不存在")
    return _experiment_full(exp)


@router.post("/{experiment_id}/rerun", summary="一键复跑（AGENT §21：历史实验可重放）")
def rerun_experiment(
    experiment_id: str,
    background: BackgroundTasks,
    session: DbSession,
    experiment_repo: ExperimentRepoDep,
    job_repo: JobRepoDep,
) -> dict:
    exp = experiment_repo.get(experiment_id)
    if exp is None:
        raise HTTPException(status_code=404, detail=f"Experiment {experiment_id} 不存在")
    job = JobRecord(
        id=new_id("JOB"),
        kind=exp.kind,
        spec_json=exp.spec_json,
        status=JobStatus.QUEUED,
        created_at=datetime.now(),
    )
    job_repo.create(job)
    session.commit()
    background.add_task(execute_job, job.id, **_bg_factories())
    return {"job_id": job.id, "status": job.status, "origin_experiment": exp.id}