#!/usr/bin/env python3
"""
FastAPI server for hybrid PDF extraction.

Endpoints:
- GET /health
- POST /extract-pdf-text (multipart: file, max_pages, ocr_lang)
"""

from __future__ import annotations

import os
import tempfile
from pathlib import Path
from typing import Optional

from fastapi import FastAPI, File, Form, Header, HTTPException, UploadFile
from fastapi.responses import JSONResponse

try:
    from .extract_pdf_text import run as extract_run
except ImportError:
    # Fallback when running as a plain script from this folder.
    from extract_pdf_text import run as extract_run


app = FastAPI(title="ScriptAI PDF Extractor API", version="1.0.0")


@app.get("/")
def root_health() -> dict:
    # Many platforms probe GET / for health checks.
    return {"ok": True, "service": "pdf-extractor", "endpoint": "/extract-pdf-text"}


@app.get("/health")
def health() -> dict:
    return {"ok": True, "service": "pdf-extractor"}


def ensure_authorized(authorization: Optional[str]) -> None:
    expected_token = (os.getenv("PYTHON_EXTRACTOR_TOKEN") or "").strip()
    if expected_token == "":
        return

    bearer = (authorization or "").strip()
    if not bearer.startswith("Bearer "):
        raise HTTPException(status_code=401, detail="Unauthorized")

    received = bearer[7:].strip()
    if received != expected_token:
        raise HTTPException(status_code=401, detail="Unauthorized")


@app.post("/extract-pdf-text")
async def extract_pdf_text(
    file: UploadFile = File(...),
    max_pages: int = Form(20),
    ocr_lang: str = Form("ind+eng"),
    authorization: Optional[str] = Header(default=None),
) -> JSONResponse:
    ensure_authorized(authorization)

    max_pages = max(1, min(max_pages, 80))

    suffix = ".pdf"
    temp_path: Optional[Path] = None

    try:
        with tempfile.NamedTemporaryFile(delete=False, suffix=suffix) as tmp:
            temp_path = Path(tmp.name)
            while True:
                chunk = await file.read(1024 * 1024)
                if not chunk:
                    break
                tmp.write(chunk)

        payload = extract_run(str(temp_path), max_pages=max_pages, ocr_lang=ocr_lang)

        status = 200 if payload.get("success") else 422
        return JSONResponse(payload, status_code=status)
    except HTTPException:
        raise
    except Exception as exc:
        return JSONResponse(
            {
                "success": False,
                "mode": "error",
                "engine": "none",
                "text": "",
                "error": str(exc),
            },
            status_code=500,
        )
    finally:
        await file.close()
        if temp_path and temp_path.exists():
            temp_path.unlink(missing_ok=True)


@app.post("/")
async def extract_pdf_text_root(
    file: UploadFile = File(...),
    max_pages: int = Form(20),
    ocr_lang: str = Form("ind+eng"),
    authorization: Optional[str] = Header(default=None),
) -> JSONResponse:
    # Alias endpoint to keep compatibility with simple base URL posting.
    return await extract_pdf_text(file=file, max_pages=max_pages, ocr_lang=ocr_lang, authorization=authorization)


@app.post("/api/extract-pdf-text")
async def extract_pdf_text_api_alias(
    file: UploadFile = File(...),
    max_pages: int = Form(20),
    ocr_lang: str = Form("ind+eng"),
    authorization: Optional[str] = Header(default=None),
) -> JSONResponse:
    # Compatibility alias used by Laravel fallback endpoint list.
    return await extract_pdf_text(file=file, max_pages=max_pages, ocr_lang=ocr_lang, authorization=authorization)


@app.post("/extract/pdf-text")
async def extract_pdf_text_legacy_alias(
    file: UploadFile = File(...),
    max_pages: int = Form(20),
    ocr_lang: str = Form("ind+eng"),
    authorization: Optional[str] = Header(default=None),
) -> JSONResponse:
    # Legacy compatibility alias used by older clients.
    return await extract_pdf_text(file=file, max_pages=max_pages, ocr_lang=ocr_lang, authorization=authorization)