from __future__ import annotations

import os
from typing import Any

from fastapi import FastAPI, HTTPException, Request, Response
from fastapi.responses import HTMLResponse, JSONResponse

from .renderer import ALLOWED_THEMES, pdf_filename, render_documents, render_pdf_with_gotenberg
from .theme_catalog import public_theme_catalog
from .validation import validate_report

app = FastAPI(
    title="Monthly Report Renderer",
    version="2.0.0",
    description="Validiert Report-Payloads, rendert feste HTML-Templates und erzeugt PDFs via Gotenberg.",
)


@app.middleware("http")
async def limit_request_size(request: Request, call_next):
    max_bytes = int(os.getenv("MAX_PAYLOAD_BYTES", "2097152"))
    content_length = request.headers.get("content-length")
    if content_length and int(content_length) > max_bytes:
        return JSONResponse(status_code=413, content={"detail": "Payload too large"})
    return await call_next(request)


@app.get("/health")
def health() -> dict[str, Any]:
    return {"status": "ok", "service": "monthly-report-renderer", "version": "2.0.0", "theme_count": len(ALLOWED_THEMES)}


@app.get("/themes")
def themes() -> dict[str, Any]:
    return {"themes": sorted(ALLOWED_THEMES), "catalog": public_theme_catalog()}


@app.post("/validate")
def validate(payload: dict[str, Any]) -> dict[str, Any]:
    errors = validate_report(payload)
    return {"valid": not errors, "errors": errors}


def _ensure_valid(payload: dict[str, Any]) -> None:
    errors = validate_report(payload)
    if errors:
        raise HTTPException(status_code=422, detail={"message": "Invalid report payload", "errors": errors})


@app.post("/preview/html", response_class=HTMLResponse)
def preview_html(payload: dict[str, Any]) -> HTMLResponse:
    _ensure_valid(payload)
    html, _ = render_documents(payload)
    return HTMLResponse(content=html, status_code=200)


@app.post("/render")
def render(payload: dict[str, Any]) -> Response:
    _ensure_valid(payload)
    try:
        pdf = render_pdf_with_gotenberg(payload)
    except Exception as exc:
        raise HTTPException(status_code=502, detail=f"PDF rendering failed: {exc}") from exc

    filename = pdf_filename(payload)
    return Response(
        content=pdf,
        media_type="application/pdf",
        headers={
            "Content-Disposition": f'attachment; filename="{filename}"',
            "X-Report-Version": payload["report"]["report_version"],
            "X-Template-Version": payload["report"]["template_version"],
        },
    )