import os
import shutil
import subprocess
import tempfile

from fastapi import FastAPI, HTTPException
from fastapi.responses import Response
from pydantic import BaseModel

app = FastAPI(title="Tectonic LaTeX Compiler API")

TECTONIC = "/app/tectonic"


class CompileRequest(BaseModel):
    tex: str


@app.get("/")
def health():
    return {
        "status": "ok",
        "service": "tectonic",
        "tectonic_exists": os.path.exists(TECTONIC),
        "tectonic_executable": os.access(TECTONIC, os.X_OK),
        "endpoint": "POST /compile",
    }


@app.post("/compile")
def compile_tex(request: CompileRequest):

    if not request.tex.strip():
        raise HTTPException(400, "No LaTeX code provided")

    if len(request.tex) > 2_000_000:
        raise HTTPException(413, "LaTeX source too large")

    workdir = tempfile.mkdtemp(prefix="tectonic_")

    try:
        tex_path = os.path.join(workdir, "resume.tex")

        with open(tex_path, "w", encoding="utf-8") as f:
            f.write(request.tex)

        result = subprocess.run(
            [
                TECTONIC,
                "-X",
                "compile",
                "--untrusted",
                "resume.tex",
            ],
            cwd=workdir,
            capture_output=True,
            text=True,
            timeout=120,
        )

        print("TECTONIC STDOUT:")
        print(result.stdout)

        print("TECTONIC STDERR:")
        print(result.stderr)

        pdf_path = os.path.join(workdir, "resume.pdf")

        if result.returncode != 0:
            raise HTTPException(
                status_code=500,
                detail={
                    "returncode": result.returncode,
                    "stdout": result.stdout[-5000:],
                    "stderr": result.stderr[-5000:],
                },
            )

        if not os.path.exists(pdf_path):
            raise HTTPException(
                status_code=500,
                detail="Tectonic finished but resume.pdf was not created",
            )

        with open(pdf_path, "rb") as f:
            pdf_data = f.read()

        return Response(
            content=pdf_data,
            media_type="application/pdf",
            headers={
                "Content-Disposition": 'attachment; filename="resume.pdf"'
            },
        )

    except subprocess.TimeoutExpired:
        raise HTTPException(
            status_code=408,
            detail="Tectonic compilation timed out",
        )

    except HTTPException:
        raise

    except Exception as e:
        raise HTTPException(
            status_code=500,
            detail=str(e),
        )

    finally:
        shutil.rmtree(workdir, ignore_errors=True)