"""FastAPI server for serving RecallTrace in Docker or Hugging Face Spaces."""

from __future__ import annotations

from pathlib import Path
from typing import Optional

import uvicorn
from fastapi import FastAPI, HTTPException
from fastapi.responses import FileResponse, JSONResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel

from baseline.policy import choose_heuristic_action
from env.env import RecallTraceEnv
from env.models import RecallAction


BASE_DIR = Path(__file__).resolve().parent
STATIC_DIR = BASE_DIR / "static"

app = FastAPI(title="RecallTrace OpenEnv", version="1.0.0")

# FIX 1: Only mount static files if the directory actually exists
if STATIC_DIR.exists():
    app.mount("/static", StaticFiles(directory=STATIC_DIR), name="static")

# FIX 2: Lazy-init the env so a constructor crash doesn't kill the server
_active_env: RecallTraceEnv | None = None


def get_active_env() -> RecallTraceEnv:
    global _active_env
    if _active_env is None:
        _active_env = RecallTraceEnv()
    return _active_env


class ResetRequest(BaseModel):
    task_id: Optional[str] = None
    phase: Optional[int] = None


class RunEpisodeRequest(BaseModel):
    task_id: Optional[str] = None
    phase: Optional[int] = None


@app.get("/")
def root():
    index = STATIC_DIR / "index.html"
    if index.exists():
        return FileResponse(index)
    return JSONResponse({"status": "RecallTrace OpenEnv running"})


@app.get("/health")
def health() -> dict:
    return {"status": "healthy"}


@app.get("/tasks")
def tasks() -> dict:
    return {"tasks": [task.model_dump() for task in RecallTraceEnv.available_tasks()]}


@app.get("/api/tasks")
def api_tasks() -> dict:
    return tasks()


@app.get("/reset")
def reset_get(task_id: Optional[str] = None, phase: Optional[int] = None) -> dict:
    try:
        return get_active_env().reset(task_id=task_id, phase=phase).model_dump()
    except Exception as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@app.post("/reset")
def reset_post(request: ResetRequest = None) -> dict:
    try:
        req = request or ResetRequest()
        return get_active_env().reset(task_id=req.task_id, phase=req.phase).model_dump()
    except Exception as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@app.post("/step")
def step(action: RecallAction) -> dict:
    try:
        observation, reward, done, info = get_active_env().step(action)
        return {
            "observation": observation.model_dump(),
            "reward": reward,
            "done": done,
            "info": info,
        }
    except Exception as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@app.get("/state")
def state() -> dict:
    return get_active_env().state().model_dump()


def _run_episode(task_id: str | None = None, phase: int | None = None) -> dict:
    env = RecallTraceEnv(task_id=task_id, phase=phase)
    observation = env.reset(task_id=task_id, phase=phase)
    logs = []
    final_info = {"score": 0.0}

    for step_number in range(1, env.task.max_steps + 1):
        action = choose_heuristic_action(observation)
        observation, reward, done, info = env.step(action)
        logs.append(
            {
                "step": step_number,
                "action": action.model_dump(exclude_none=True),
                "reward": reward,
                "done": done,
                "message": info.get("message"),
            }
        )
        final_info = info
        if done:
            break

    return {
        "task": env.task.model_dump(),
        "score": float(final_info.get("score", 0.0)),
        "success": float(final_info.get("score", 0.0)) >= 0.9,
        "steps_taken": env.state().steps_taken,
        "final_info": final_info,
        "final_observation": observation.model_dump(),
        "logs": logs,
    }


@app.post("/api/run_episode")
def run_episode(request: RunEpisodeRequest) -> dict:
    try:
        return _run_episode(task_id=request.task_id, phase=request.phase)
    except Exception as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@app.get("/api/run_all")
def run_all() -> dict:
    try:
        episodes = [_run_episode(task_id=task.task_id) for task in RecallTraceEnv.available_tasks()]
        average_score = round(sum(item["score"] for item in episodes) / len(episodes), 4)
        return {
            "average_score": average_score,
            "episodes": episodes,
        }
    except Exception as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


def main() -> None:
    uvicorn.run(app, host="0.0.0.0", port=7860)


if __name__ == "__main__":
    main()