import datetime
import os
from contextlib import asynccontextmanager
from pathlib import Path

from fastapi import FastAPI, HTTPException
from pydantic import BaseModel, Field

from services.ledger import LedgerService


def _ledger_path() -> Path:
    env_path = os.getenv("LEDGER_FILE")
    if env_path:
        return Path(env_path)

    return Path.cwd() / "ledger.beancount"


class QueryRequest(BaseModel):
    query: str = Field(min_length=1)


@asynccontextmanager
async def lifespan(application: FastAPI):
    ledger_path = _ledger_path()
    service = LedgerService(ledger_path)
    application.state.ledger_service = service

    await service.start()

    try:
        yield
    finally:
        await service.stop()


app = FastAPI(lifespan=lifespan)


@app.get("/")
async def root():
    return {"message": "Ledger API"}


@app.get("/status")
async def status():
    service: LedgerService = app.state.ledger_service
    snapshot = await service.snapshot()

    return {
        "ledger_path": str(service.ledger_path),
        "last_loaded_at": snapshot.last_loaded_at.isoformat() + "Z",
        "error_count": len(snapshot.errors),
        "errors": [str(err) for err in snapshot.errors],
        "options": snapshot.options_map,
    }


@app.get("/accounts")
async def accounts(on_date: datetime.date | None = None):
    service: LedgerService = app.state.ledger_service
    return await service.account_balances(on_date)


@app.get("/journal")
async def journal(limit: int | None = None):
    service: LedgerService = app.state.ledger_service
    return await service.journal_entries(limit)


@app.post("/query")
async def query(payload: QueryRequest):
    service: LedgerService = app.state.ledger_service

    try:
        return await service.run_query(payload.query)
    except Exception as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc