"""
main.py - Thin FastAPI app: upload a PDF, run the pipeline, return the report.

Run from the project root:
    uvicorn backend.main:app --reload

The pipeline is synchronous and can take minutes on a large set; for a single
architect checking one set at a time that's fine. Move to a job queue if this
ever needs concurrency.
"""

import os
import tempfile
from typing import Optional

from fastapi import FastAPI, UploadFile, File, Form, HTTPException
from fastapi.responses import HTMLResponse, JSONResponse, Response
from fastapi.staticfiles import StaticFiles

from backend import config
from backend.jobs import create_job, get_job
from backend.pipeline.pdf_processor import render_page_jpeg

app = FastAPI(title=config.APP_TITLE, version=config.APP_VERSION)

_FRONTEND_DIR = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "frontend")


@app.get("/health")
def health():
    return {"status": "ok", "model": config.MODEL,
            "key_configured": bool(config.AI_API_KEY),
            "email_configured": bool(config.SMTP_HOST and config.SMTP_USER and config.SMTP_PASSWORD)}


@app.post("/check")
async def check(
    file: UploadFile = File(...),
    notification_email: Optional[str] = Form(None),
    project_name: Optional[str] = Form(None),
    address: Optional[str] = Form(None),
    occupancy: Optional[str] = Form(None),
    work_type: Optional[str] = Form(None),
    text_local: bool = Form(False),
):
    """
    Accept a PDF, start a background conflict check, and return a job_id
    immediately. The client can poll GET /jobs/{id} or just wait for the email.

    Optional intake fields (project_name/address/occupancy/work_type) feed the
    Stage 0 jurisdiction profile; anything left blank is derived from the cover
    sheet.
    """
    if not file.filename.lower().endswith(".pdf"):
        raise HTTPException(status_code=400, detail="Please upload a PDF.")

    os.makedirs(config.UPLOAD_DIR, exist_ok=True)
    suffix = "_" + os.path.basename(file.filename)
    fd, tmp_path = tempfile.mkstemp(suffix=suffix, dir=config.UPLOAD_DIR)
    with os.fdopen(fd, "wb") as f:
        f.write(await file.read())

    email = (notification_email or "").strip() or None
    project_input = {
        k: v.strip()
        for k, v in {
            "project_name": project_name, "address": address,
            "occupancy": occupancy, "work_type": work_type,
        }.items()
        if v and v.strip()
    }
    job_id = create_job(tmp_path, source_filename=file.filename, email=email,
                        project_input=project_input, text_local=text_local)
    return JSONResponse({"job_id": job_id, "status": "queued", "email": email})


@app.get("/jobs/{job_id}")
def job_status(job_id: str):
    job = get_job(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job not found")
    return JSONResponse(job)


@app.get("/jobs/{job_id}/sheet-image/{page}")
def sheet_image(job_id: str, page: int):
    """Render one page of a completed job's source PDF as JPEG (sheet viewer)."""
    pdf = os.path.join(config.OUTPUT_DIR, job_id, "source.pdf")
    if not os.path.isfile(pdf):
        raise HTTPException(status_code=404, detail="Source PDF not found for this job")
    try:
        data = render_page_jpeg(pdf, page)
    except IndexError:
        raise HTTPException(status_code=404, detail=f"Page {page} out of range")
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Could not render page: {e}")
    return Response(content=data, media_type="image/jpeg",
                    headers={"Cache-Control": "max-age=3600"})


@app.get("/", response_class=HTMLResponse)
def index():
    index_path = os.path.join(_FRONTEND_DIR, "index.html")
    if os.path.isfile(index_path):
        with open(index_path) as f:
            return f.read()
    return "<h1>Conflict Checker</h1><p>frontend/index.html not found.</p>"


# Serve any other static assets (none required for the single-file UI).
if os.path.isdir(_FRONTEND_DIR):
    app.mount("/static", StaticFiles(directory=_FRONTEND_DIR), name="static")