from flask import Flask, render_template, request, redirect, url_for, session, flash
import json
import os
from datetime import datetime
from pathlib import Path

app = Flask(__name__)
app.secret_key = "your-secret-key-change-in-production"

DATA_DIR = Path("data")
USERS_FILE = DATA_DIR / "users.json"


# Initialize data directory and default user
def init_data():
    DATA_DIR.mkdir(exist_ok=True)
    if not USERS_FILE.exists():
        default_user = {"admin": {"password": "123"}}
        with open(USERS_FILE, "w") as f:
            json.dump(default_user, f)


init_data()


# User management
def load_users():
    with open(USERS_FILE, "r") as f:
        return json.load(f)


def save_users(users):
    with open(USERS_FILE, "w") as f:
        json.dump(users, f, indent=2)


# Note management
def get_user_notes(username):
    user_dir = DATA_DIR / username
    if not user_dir.exists():
        return []

    notes = []
    for note_file in sorted(user_dir.glob("note_*.txt"), reverse=True):
        timestamp = note_file.stem.replace("note_", "")
        with open(note_file, "r") as f:
            content = f.read()
        notes.append(
            {"timestamp": timestamp, "content": content, "filename": note_file.name}
        )
    return notes


def save_note(username, content):
    user_dir = DATA_DIR / username
    user_dir.mkdir(exist_ok=True)

    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    note_file = user_dir / f"note_{timestamp}.txt"

    with open(note_file, "w") as f:
        f.write(content)


def delete_note(username, filename):
    note_file = DATA_DIR / username / filename
    if note_file.exists():
        note_file.unlink()


# Routes
@app.route("/")
def index():
    if "username" in session:
        return redirect(url_for("dashboard"))
    return render_template("index.html", page="login")


@app.route("/login", methods=["POST"])
def login():
    username = request.form.get("username")
    password = request.form.get("password")

    users = load_users()
    if username in users and users[username]["password"] == password:
        session["username"] = username
        return redirect(url_for("dashboard"))

    flash("Invalid credentials", "error")
    return redirect(url_for("index"))


@app.route("/signup", methods=["GET", "POST"])
def signup():
    if request.method == "GET":
        return render_template("index.html", page="signup")

    username = request.form.get("username")
    password = request.form.get("password")

    users = load_users()
    if username in users:
        flash("Username already exists", "error")
        return redirect(url_for("signup"))

    users[username] = {"password": password}
    save_users(users)
    session["username"] = username
    return redirect(url_for("dashboard"))


@app.route("/dashboard")
def dashboard():
    if "username" not in session:
        return redirect(url_for("index"))

    username = session["username"]
    notes = get_user_notes(username)
    return render_template(
        "index.html", page="dashboard", username=username, notes=notes
    )


@app.route("/add_note", methods=["POST"])
def add_note():
    if "username" not in session:
        return redirect(url_for("index"))

    content = request.form.get("content", "").strip()
    if content:
        save_note(session["username"], content)
        flash("Note added successfully", "success")

    return redirect(url_for("dashboard"))


@app.route("/delete_note/<filename>")
def delete_note_route(filename):
    if "username" not in session:
        return redirect(url_for("index"))

    delete_note(session["username"], filename)
    flash("Note deleted", "success")
    return redirect(url_for("dashboard"))


@app.route("/logout")
def logout():
    session.pop("username", None)
    return redirect(url_for("index"))


if __name__ == "__main__":
    app.run(debug=True)