app.py

import json
import os
import uuid
from datetime import datetime, timezone

from flask import Flask, jsonify, request, render_template

app = Flask(__name__)

# Where notes are stored. Override with the NOTES_FILE env var if you like.
DATA_FILE = os.environ.get("NOTES_FILE", os.path.join(os.path.dirname(__file__), "notes.json"))


def _read_notes():
    """Load notes from disk, returning a list. Never crashes on a missing/empty file."""
    if not os.path.exists(DATA_FILE):
        return []
    try:
        with open(DATA_FILE, "r", encoding="utf-8") as f:
            data = json.load(f)
            return data if isinstance(data, list) else []
    except (json.JSONDecodeError, OSError):
        return []


def _write_notes(notes):
    """Persist the full notes list to disk."""
    with open(DATA_FILE, "w", encoding="utf-8") as f:
        json.dump(notes, f, indent=2, ensure_ascii=False)


@app.route("/")
def index():
    """Serve the single-page frontend."""
    return render_template("index.html")


@app.route("/notes", methods=["GET"])
def get_notes():
    """Return all notes, newest first."""
    notes = _read_notes()
    notes.sort(key=lambda n: n.get("created_at", ""), reverse=True)
    return jsonify(notes)


@app.route("/notes", methods=["POST"])
def create_note():
    """Create a new note from JSON body { "text": "..." }."""
    payload = request.get_json(silent=True) or {}
    text = (payload.get("text") or "").strip()

    if not text:
        return jsonify({"error": "Note text cannot be empty."}), 400

    note = {
        "id": uuid.uuid4().hex,
        "text": text,
        "created_at": datetime.now(timezone.utc).isoformat(),
    }

    notes = _read_notes()
    notes.append(note)
    _write_notes(notes)

    return jsonify(note), 201


@app.route("/notes/<note_id>", methods=["DELETE"])
def delete_note(note_id):
    """Delete a note by id."""
    notes = _read_notes()
    remaining = [n for n in notes if n.get("id") != note_id]

    if len(remaining) == len(notes):
        return jsonify({"error": "Note not found."}), 404

    _write_notes(remaining)
    return jsonify({"deleted": note_id})


if __name__ == "__main__":
    # Local dev server. In production, gunicorn runs the app (see Procfile).
    port = int(os.environ.get("PORT", 5000))
    app.run(host="0.0.0.0", port=port, debug=True)