#!/usr/bin/env python3
"""
Simple Tablet Lending and Return Management System
Using only built-in Python modules (no Flask required)
"""

import sqlite3
import os
from datetime import datetime
from http.server import HTTPServer, BaseHTTPRequestHandler
from urllib.parse import parse_qs, urlparse
import json

# Database setup
DATABASE = 'tablets.db'

def get_db():
    """Get database connection"""
    conn = sqlite3.connect(DATABASE)
    conn.row_factory = sqlite3.Row
    return conn

def init_db():
    """Initialize database with required tables"""
    with get_db() as conn:
        cursor = conn.cursor()
        
        # Create tablets table
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS tablets (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                brand TEXT NOT NULL,
                model TEXT NOT NULL,
                serial_number TEXT UNIQUE NOT NULL,
                status TEXT DEFAULT 'available',
                notes TEXT
            )
        ''')
        
        # Create users table
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS users (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                name TEXT NOT NULL,
                email TEXT,
                phone TEXT,
                identification TEXT UNIQUE
            )
        ''')
        
        # Create loans table
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS loans (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                tablet_id INTEGER NOT NULL,
                user_id INTEGER NOT NULL,
                loan_date TEXT NOT NULL,
                return_date TEXT,
                status TEXT DEFAULT 'active',
                FOREIGN KEY (tablet_id) REFERENCES tablets (id),
                FOREIGN KEY (user_id) REFERENCES users (id)
            )
        ''')
        
        # Create non_loanable_devices table
        cursor.execute('''
            CREATE TABLE IF NOT EXISTS non_loanable_devices (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                brand TEXT NOT NULL,
                model TEXT NOT NULL,
                serial_number TEXT UNIQUE NOT NULL,
                device_type TEXT NOT NULL,
                location TEXT,
                status TEXT DEFAULT 'available',
                notes TEXT,
                purchase_date TEXT,
                purchase_cost REAL
            )
        ''')
        
        conn.commit()

class SimpleHTTPRequestHandler(BaseHTTPRequestHandler):
    def _set_headers(self, content_type="text/html"):
        self.send_response(200)
        self.send_header('Content-type', content_type)
        self.end_headers()
    
    def _send_html(self, content):
        self._set_headers()
        self.wfile.write(content.encode('utf-8'))
    
    def _send_json(self, data):
        self._set_headers(content_type="application/json")
        self.wfile.write(json.dumps(data).encode('utf-8'))
    
    def _parse_form_data(self):
        content_length = int(self.headers['Content-Length'])
        post_data = self.rfile.read(content_length)
        return parse_qs(post_data.decode('utf-8'))
    
    def do_GET(self):
        parsed_path = urlparse(self.path)
        
        if parsed_path.path == '/':
            self._handle_index()
        elif parsed_path.path == '/add_tablet':
            self._handle_add_tablet_form()
        elif parsed_path.path == '/add_user':
            self._handle_add_user_form()
        elif parsed_path.path == '/loan_tablet':
            self._handle_loan_tablet_form()
        elif parsed_path.path == '/history':
            self._handle_history()
        elif parsed_path.path.startswith('/return_tablet/'):
            self._handle_return_tablet(parsed_path.path)
        else:
            self._send_html("<h1>404 Not Found</h1>")
    
    def do_POST(self):
        parsed_path = urlparse(self.path)
        
        if parsed_path.path == '/add_tablet':
            self._handle_add_tablet()
        elif parsed_path.path == '/add_user':
            self._handle_add_user()
        elif parsed_path.path == '/loan_tablet':
            self._handle_loan_tablet()
        else:
            self._send_html("<h1>404 Not Found</h1>")
    
    def _handle_index(self):
        with get_db() as conn:
            cursor = conn.cursor()
            
            # Get available tablets
            cursor.execute("SELECT * FROM tablets WHERE status = 'available'")
            available_tablets = cursor.fetchall()
            
            # Get active loans
            cursor.execute('''
                SELECT l.id, t.brand, t.model, t.serial_number, u.name, l.loan_date
                FROM loans l
                JOIN tablets t ON l.tablet_id = t.id
                JOIN users u ON l.user_id = u.id
                WHERE l.status = 'active'
            ''')
            active_loans = cursor.fetchall()
        
        html = f"""
        <!DOCTYPE html>
        <html>
        <head>
            <title>Tablet Management System</title>
            <style>
                body {{ font-family: Arial, sans-serif; margin: 20px; }}
                h1 {{ color: #333; }}
                .nav {{ margin-bottom: 20px; }}
                .nav a {{ margin-right: 15px; text-decoration: none; color: #4CAF50; }}
                table {{ width: 100%; border-collapse: collapse; margin-bottom: 20px; }}
                th, td {{ padding: 10px; text-align: left; border-bottom: 1px solid #ddd; }}
                th {{ background-color: #4CAF50; color: white; }}
                .btn {{ padding: 5px 10px; background-color: #4CAF50; color: white; text-decoration: none; border-radius: 3px; }}
                .btn-danger {{ background-color: #f44336; }}
            </style>
        </head>
        <body>
            <h1>Tablet Management System</h1>
            <div class="nav">
                <a href="/">Home</a>
                <a href="/add_tablet">Add Tablet</a>
                <a href="/add_user">Add User</a>
                <a href="/loan_tablet">Loan Tablet</a>
                <a href="/history">Loan History</a>
            </div>
            
            <h2>Available Tablets</h2>
            <table>
                <thead>
                    <tr>
                        <th>Brand</th>
                        <th>Model</th>
                        <th>Serial Number</th>
                        <th>Notes</th>
                    </tr>
                </thead>
                <tbody>
        """
        
        if available_tablets:
            for tablet in available_tablets:
                html += f"""
                    <tr>
                        <td>{tablet['brand']}</td>
                        <td>{tablet['model']}</td>
                        <td>{tablet['serial_number']}</td>
                        <td>{tablet['notes'] or '-'}</td>
                    </tr>
                """
        else:
            html += "<tr><td colspan='4'>No available tablets.</td></tr>"
        
        html += """
                </tbody>
            </table>
            
            <h2>Active Loans</h2>
            <table>
                <thead>
                    <tr>
                        <th>Tablet</th>
                        <th>Serial Number</th>
                        <th>Borrower</th>
                        <th>Loan Date</th>
                        <th>Actions</th>
                    </tr>
                </thead>
                <tbody>
        """
        
        if active_loans:
            for loan in active_loans:
                html += f"""
                    <tr>
                        <td>{loan['brand']} {loan['model']}</td>
                        <td>{loan['serial_number']}</td>
                        <td>{loan['name']}</td>
                        <td>{loan['loan_date']}</td>
                        <td><a href='/return_tablet/{loan['id']}' class='btn btn-danger'>Return</a></td>
                    </tr>
                """
        else:
            html += "<tr><td colspan='5'>No active loans.</td></tr>"
        
        html += """
                </tbody>
            </table>
        </body>
        </html>
        """
        
        self._send_html(html)
    
    def _handle_add_tablet_form(self):
        html = """
        <!DOCTYPE html>
        <html>
        <head>
            <title>Add Tablet</title>
            <style>
                body { font-family: Arial, sans-serif; margin: 20px; }
                .form-group { margin-bottom: 15px; }
                label { display: block; margin-bottom: 5px; }
                input, textarea { width: 100%; padding: 8px; }
                .btn { padding: 8px 16px; background-color: #4CAF50; color: white; border: none; cursor: pointer; }
            </style>
        </head>
        <body>
            <h1>Add New Tablet</h1>
            <form method="POST" action="/add_tablet">
                <div class="form-group">
                    <label for="brand">Brand:</label>
                    <input type="text" id="brand" name="brand" required>
                </div>
                <div class="form-group">
                    <label for="model">Model:</label>
                    <input type="text" id="model" name="model" required>
                </div>
                <div class="form-group">
                    <label for="serial_number">Serial Number:</label>
                    <input type="text" id="serial_number" name="serial_number" required>
                </div>
                <div class="form-group">
                    <label for="notes">Notes:</label>
                    <textarea id="notes" name="notes"></textarea>
                </div>
                <div class="form-group">
                    <button type="submit" class="btn">Add Tablet</button>
                </div>
            </form>
        </body>
        </html>
        """
        self._send_html(html)
    
    def _handle_add_tablet(self):
        form_data = self._parse_form_data()
        brand = form_data['brand'][0]
        model = form_data['model'][0]
        serial_number = form_data['serial_number'][0]
        notes = form_data.get('notes', [''])[0]
        
        try:
            with get_db() as conn:
                cursor = conn.cursor()
                cursor.execute('''
                    INSERT INTO tablets (brand, model, serial_number, status, notes)
                    VALUES (?, ?, ?, 'available', ?)
                ''', (brand, model, serial_number, notes))
                conn.commit()
            
            self.send_response(303)
            self.send_header('Location', '/')
            self.end_headers()
        except sqlite3.IntegrityError:
            self._send_html("<h1>Error: Serial number already exists!</h1><p><a href='/add_tablet'>Try again</a></p>")
    
    def _handle_add_user_form(self):
        html = """
        <!DOCTYPE html>
        <html>
        <head>
            <title>Add User</title>
            <style>
                body { font-family: Arial, sans-serif; margin: 20px; }
                .form-group { margin-bottom: 15px; }
                label { display: block; margin-bottom: 5px; }
                input { width: 100%; padding: 8px; }
                .btn { padding: 8px 16px; background-color: #4CAF50; color: white; border: none; cursor: pointer; }
            </style>
        </head>
        <body>
            <h1>Add New User</h1>
            <form method="POST" action="/add_user">
                <div class="form-group">
                    <label for="name">Name:</label>
                    <input type="text" id="name" name="name" required>
                </div>
                <div class="form-group">
                    <label for="email">Email:</label>
                    <input type="email" id="email" name="email">
                </div>
                <div class="form-group">
                    <label for="phone">Phone:</label>
                    <input type="text" id="phone" name="phone">
                </div>
                <div class="form-group">
                    <label for="identification">Identification:</label>
                    <input type="text" id="identification" name="identification" required>
                </div>
                <div class="form-group">
                    <button type="submit" class="btn">Add User</button>
                </div>
            </form>
        </body>
        </html>
        """
        self._send_html(html)
    
    def _handle_add_user(self):
        form_data = self._parse_form_data()
        name = form_data['name'][0]
        email = form_data.get('email', [''])[0]
        phone = form_data.get('phone', [''])[0]
        identification = form_data['identification'][0]
        
        try:
            with get_db() as conn:
                cursor = conn.cursor()
                cursor.execute('''
                    INSERT INTO users (name, email, phone, identification)
                    VALUES (?, ?, ?, ?)
                ''', (name, email, phone, identification))
                conn.commit()
            
            self.send_response(303)
            self.send_header('Location', '/')
            self.end_headers()
        except sqlite3.IntegrityError:
            self._send_html("<h1>Error: Identification already exists!</h1><p><a href='/add_user'>Try again</a></p>")
    
    def _handle_loan_tablet_form(self):
        with get_db() as conn:
            cursor = conn.cursor()
            cursor.execute("SELECT * FROM tablets WHERE status = 'available'")
            available_tablets = cursor.fetchall()
            cursor.execute("SELECT * FROM users")
            users = cursor.fetchall()
        
        html = """
        <!DOCTYPE html>
        <html>
        <head>
            <title>Loan Tablet</title>
            <style>
                body { font-family: Arial, sans-serif; margin: 20px; }
                .form-group { margin-bottom: 15px; }
                label { display: block; margin-bottom: 5px; }
                select { width: 100%; padding: 8px; }
                .btn { padding: 8px 16px; background-color: #4CAF50; color: white; border: none; cursor: pointer; }
            </style>
        </head>
        <body>
            <h1>Loan Tablet</h1>
            <form method="POST" action="/loan_tablet">
                <div class="form-group">
                    <label for="tablet_id">Tablet:</label>
                    <select id="tablet_id" name="tablet_id" required>
                        <option value="">Select a tablet</option>
        """
        
        for tablet in available_tablets:
            html += f"<option value='{tablet['id']}'>{tablet['brand']} {tablet['model']} ({tablet['serial_number']})</option>"
        
        html += """
                    </select>
                </div>
                <div class="form-group">
                    <label for="user_id">User:</label>
                    <select id="user_id" name="user_id" required>
                        <option value="">Select a user</option>
        """
        
        for user in users:
            html += f"<option value='{user['id']}'>{user['name']} ({user['identification']})</option>"
        
        html += """
                    </select>
                </div>
                <div class="form-group">
                    <button type="submit" class="btn">Loan Tablet</button>
                </div>
            </form>
        </body>
        </html>
        """
        self._send_html(html)
    
    def _handle_loan_tablet(self):
        form_data = self._parse_form_data()
        tablet_id = form_data['tablet_id'][0]
        user_id = form_data['user_id'][0]
        
        with get_db() as conn:
            cursor = conn.cursor()
            
            # Update tablet status
            cursor.execute("UPDATE tablets SET status = 'loaned' WHERE id = ?", (tablet_id,))
            
            # Create loan record
            loan_date = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
            cursor.execute('''
                INSERT INTO loans (tablet_id, user_id, loan_date, status)
                VALUES (?, ?, ?, 'active')
            ''', (tablet_id, user_id, loan_date))
            
            conn.commit()
        
        self.send_response(303)
        self.send_header('Location', '/')
        self.end_headers()
    
    def _handle_return_tablet(self, path):
        loan_id = path.split('/')[-1]
        
        with get_db() as conn:
            cursor = conn.cursor()
            
            # Get loan information
            cursor.execute("SELECT tablet_id FROM loans WHERE id = ?", (loan_id,))
            loan = cursor.fetchone()
            
            if loan:
                tablet_id = loan['tablet_id']
                
                # Update loan status and return date
                return_date = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
                cursor.execute('''
                    UPDATE loans SET status = 'returned', return_date = ? WHERE id = ?
                ''', (return_date, loan_id))
                
                # Update tablet status
                cursor.execute("UPDATE tablets SET status = 'available' WHERE id = ?", (tablet_id,))
                
                conn.commit()
        
        self.send_response(303)
        self.send_header('Location', '/')
        self.end_headers()
    
    def _handle_history(self):
        with get_db() as conn:
            cursor = conn.cursor()
            
            cursor.execute('''
                SELECT l.id, t.brand, t.model, t.serial_number, u.name, 
                       l.loan_date, l.return_date, l.status
                FROM loans l
                JOIN tablets t ON l.tablet_id = t.id
                JOIN users u ON l.user_id = u.id
                ORDER BY l.loan_date DESC
            ''')
            loans = cursor.fetchall()
        
        html = """
        <!DOCTYPE html>
        <html>
        <head>
            <title>Loan History</title>
            <style>
                body { font-family: Arial, sans-serif; margin: 20px; }
                h1 { color: #333; }
                .nav { margin-bottom: 20px; }
                .nav a { margin-right: 15px; text-decoration: none; color: #4CAF50; }
                table { width: 100%; border-collapse: collapse; }
                th, td { padding: 10px; text-align: left; border-bottom: 1px solid #ddd; }
                th { background-color: #4CAF50; color: white; }
            </style>
        </head>
        <body>
            <h1>Loan History</h1>
            <div class="nav">
                <a href="/">Home</a>
                <a href="/add_tablet">Add Tablet</a>
                <a href="/add_user">Add User</a>
                <a href="/loan_tablet">Loan Tablet</a>
                <a href="/history">Loan History</a>
            </div>
            
            <table>
                <thead>
                    <tr>
                        <th>Tablet</th>
                        <th>Serial Number</th>
                        <th>Borrower</th>
                        <th>Loan Date</th>
                        <th>Return Date</th>
                        <th>Status</th>
                    </tr>
                </thead>
                <tbody>
        """
        
        if loans:
            for loan in loans:
                html += f"""
                    <tr>
                        <td>{loan['brand']} {loan['model']}</td>
                        <td>{loan['serial_number']}</td>
                        <td>{loan['name']}</td>
                        <td>{loan['loan_date']}</td>
                        <td>{loan['return_date'] or '-'}</td>
                        <td>{loan['status']}</td>
                    </tr>
                """
        else:
            html += "<tr><td colspan='6'>No loan history available.</td></tr>"
        
        html += """
                </tbody>
            </table>
        </body>
        </html>
        """
        
        self._send_html(html)

def run_server():
    """Run the HTTP server"""
    server_address = ('', 8000)
    httpd = HTTPServer(server_address, SimpleHTTPRequestHandler)
    print(f"Server running on http://localhost:8000")
    print("Press Ctrl+C to stop the server")
    httpd.serve_forever()

if __name__ == '__main__':
    # Initialize database
    init_db()
    
    # Run the server
    run_server()