"""
server/app.py – FastAPI server for Smart Farm Resource Manager.

Exposes:
    POST /reset      -> Observation
    POST /step       -> StepResult
    GET  /state      -> dict
    GET  /health     -> dict
    GET  /tasks      -> dict
"""
from __future__ import annotations

import json
import os
from typing import Any, Dict

import uvicorn
from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware

from src.envs.smart_farm_env.models import Action, Observation, StepResult, TaskConfig
from src.envs.smart_farm_env.server.environment import SmartFarmEnv

# ---------------------------------------------------------------------------
# App
# ---------------------------------------------------------------------------

app = FastAPI(
    title="Smart Farm Resource Manager",
    description="OpenEnv-compatible precision agriculture simulation API",
    version="1.0.0",
    docs_url="/docs",      # default, but explicit
    redoc_url="/redoc",
)

@app.get("/")
async def root():
    return {
        "message": "🚜 Smart Farm Resource Manager API is running!",
        "version": "1.0.0",
        "docs": "/docs",
        "redoc": "/redoc",
        "available_endpoints": [
            "/health",
            "/reset",
            "/step",
            "/state",
            "/tasks"
        ]
    }

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_methods=["*"],
    allow_headers=["*"],
)

# Singleton env (one active episode per server instance)
_env: SmartFarmEnv | None = None

# Load task configs once at startup
_TASKS_PATH = os.path.join(os.path.dirname(__file__), "..", "tasks", "tasks.json")

with open(_TASKS_PATH) as _f:
    _tasks_raw = json.load(_f)["tasks"]

TASK_MAP: Dict[str, TaskConfig] = {t["name"]: TaskConfig(**t) for t in _tasks_raw}


def _require_env() -> SmartFarmEnv:
    if _env is None:
        raise HTTPException(status_code=400, detail="Not initialised — call POST /reset first.")
    return _env


# ---------------------------------------------------------------------------
# Endpoints
# ---------------------------------------------------------------------------

@app.get("/health")
def health() -> Dict[str, str]:
    return {"status": "ok", "env": "smart-farm-env"}


@app.post("/reset", response_model=Observation)
def reset(task_name: str = "easy") -> Observation:
    global _env
    if task_name not in TASK_MAP:
        raise HTTPException(
            status_code=404,
            detail=f"Unknown task '{task_name}'. Available: {list(TASK_MAP)}",
        )
    _env = SmartFarmEnv(TASK_MAP[task_name])
    return _env.reset()


@app.post("/step", response_model=StepResult)
def step(action: Action) -> StepResult:
    env = _require_env()
    try:
        return env.step(action)
    except RuntimeError as exc:
        raise HTTPException(status_code=400, detail=str(exc))


@app.get("/state")
def state() -> Dict[str, Any]:
    return _require_env().state()


@app.get("/tasks")
def list_tasks() -> Dict[str, Any]:
    return {
        "tasks": [
            {
                "name": t.name,
                "description": t.description,
                "num_plots": t.num_plots,
                "allowed_actions": t.allowed_actions,
            }
            for t in TASK_MAP.values()
        ]
    }


# ---------------------------------------------------------------------------
# Entry point (used by server Dockerfile CMD)
# ---------------------------------------------------------------------------

if __name__ == "__main__":
    port = int(os.environ.get("PORT", 7860))
    uvicorn.run("src.envs.smart_farm_env.server.app:app", host="0.0.0.0", port=port, reload=False)
def main():
    import uvicorn
    uvicorn.run(app, host='0.0.0.0', port=7860)

if __name__ == '__main__':
    main()