import os
import subprocess
from pathlib import Path

import pypdf
from flask import Flask, flash, redirect, render_template, request, url_for
from werkzeug.utils import secure_filename

UPLOAD_FOLDER = str(Path(__file__).parent / "uploads")
ALLOWED_EXTENSIONS = {"pdf"}
PRINTER_NAME = "HL-2270DW_series"
MAX_PAGES = 10

app = Flask(__name__)
app.config["UPLOAD_FOLDER"] = UPLOAD_FOLDER
app.config["SECRET_KEY"] = os.urandom(24)
app.config["MAX_CONTENT_LENGTH"] = 16 * 1024 * 1024


def allowed_file(filename):
    return "." in filename and filename.rsplit(".", 1)[1].lower() in ALLOWED_EXTENSIONS


def get_pdf_page_count(filepath):
    try:
        with open(filepath, "rb") as f:
            reader = pypdf.PdfReader(f)
            return len(reader.pages)
    except Exception as e:
        app.logger.error(f"Could not read PDF pages: {e}")
        return None


@app.route("/", methods=["GET", "POST"])
def upload_and_print():
    if request.method == "POST":
        if "file" not in request.files:
            flash("No file part in the request.", "error")
            return redirect(request.url)

        file = request.files["file"]

        if file.filename == "":
            flash("No file selected. Please choose a PDF to print.", "error")
            return redirect(request.url)

        if file and allowed_file(file.filename):
            filename = secure_filename(file.filename)
            os.makedirs(app.config["UPLOAD_FOLDER"], exist_ok=True)
            filepath = os.path.join(app.config["UPLOAD_FOLDER"], filename)
            file.save(filepath)

            try:
                page_count = get_pdf_page_count(filepath)
                if page_count is None:
                    flash(
                        "Could not process the PDF file. It might be corrupt.", "error"
                    )
                    return redirect(request.url)

                if page_count > MAX_PAGES:
                    flash(
                        f"Error: File has {page_count} pages. The maximum allowed is {MAX_PAGES}.",
                        "error",
                    )
                    return redirect(request.url)

                app.logger.info(
                    f"Sending '{filename}' ({page_count} pages) to printer '{PRINTER_NAME}'"
                )
                command = ["lp", "-d", PRINTER_NAME, filepath]
                result = subprocess.run(
                    command, capture_output=True, text=True, check=True
                )
                app.logger.info(f"lp command stdout: {result.stdout}")
                flash(f"Success! '{filename}' has been sent to the printer.", "success")

            except subprocess.CalledProcessError as e:
                app.logger.error(f"Error printing file: {e}")
                app.logger.error(f"lp command stderr: {e.stderr}")
                flash(
                    "Error sending file to printer. The printer may be offline or misconfigured.",
                    "error",
                )

            except Exception as e:
                app.logger.error(f"An unexpected error occurred: {e}")
                flash("An unexpected server error occurred.", "error")

            finally:
                if os.path.exists(filepath):
                    os.remove(filepath)
                    app.logger.info(f"Cleaned up temporary file: {filepath}")

            return redirect(url_for("upload_and_print"))

        else:
            flash("Invalid file type. Please upload a PDF file.", "error")
            return redirect(request.url)

    return render_template("index.html", printer_name=PRINTER_NAME, max_pages=MAX_PAGES)


if __name__ == "__main__":
    app.run(host="127.0.0.1", port=57928, debug=False)