"""
FastAPI app exposing the warehouse fulfillment environment.
"""

from __future__ import annotations
from typing import Optional
from fastapi import FastAPI, HTTPException
from pydantic import BaseModel, Field
from grid_env.Server.warehouse_env import WarehouseEnvService

app = FastAPI(
    title="Warehouse Fulfillment Env Server",
    version="0.1.0",
    description="HTTP server for the MiniGrid-style warehouse fulfillment environment.",
)
service = WarehouseEnvService()


class ResetRequest(BaseModel):
    task_id: Optional[str] = Field(default=None, description="Task ID to load on reset.")
    seed: Optional[int] = Field(default=None, description="Optional deterministic seed.")


class StepRequest(BaseModel):
    command: str = Field(description="Environment action command.")


@app.get("/health")
def health() -> dict:
    return service.health()


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


@app.post("/reset")
def reset(payload: ResetRequest = None) -> dict:
    task_id = payload.task_id if payload else None
    seed = payload.seed if payload else None
    try:
        return service.reset(task_id=task_id, seed=seed)
    except KeyError as exc:
        raise HTTPException(status_code=404, detail=str(exc)) from exc


@app.post("/step")
def step(payload: StepRequest) -> dict:
    try:
        return service.step(command=payload.command)
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


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


def main() -> None:
    import uvicorn

    uvicorn.run("grid_env.Server.app:app", host="0.0.0.0", port=8000, reload=False)