import gradio as gr
import sqlite3
from utils import get_device_id, authenticate_user, get_user_role
from database import (
    init_db, add_student, get_sessions, toggle_session,
    get_open_session, has_marked_attendance, mark_attendance, get_attendance_summary
)

# Initialize the database
init_db()

# Global user state
current_user = {"email": None, "role": None, "device_id": None, "class_id": None}

# Custom theme for the app
theme = gr.themes.Soft(
    primary_hue="indigo",
    secondary_hue="blue",
    neutral_hue="slate",
    radius_size=gr.themes.sizes.radius_md,
).set(
    button_primary_background_fill="*primary_500",
    button_primary_background_fill_hover="*primary_600",
    button_primary_text_color="white",
    button_secondary_background_fill="*neutral_100",
    button_secondary_background_fill_hover="*neutral_200",
    button_secondary_text_color="*neutral_800",
    block_label_background_fill="*neutral_50",
    block_title_text_weight="600",
)

# --- Login Logic ---
def login(email, password):
    if not email or not password:
        return "Please fill in all fields.", gr.update(visible=False), gr.update(visible=True)
    
    device_id = get_device_id()
    success, message = authenticate_user(email, password, device_id)
    
    if success:
        current_user["email"] = email
        current_user["role"] = get_user_role(email)
        current_user["device_id"] = device_id

        # Get class_id and name
        conn = sqlite3.connect("attendance.db")
        cursor = conn.cursor()
        cursor.execute("SELECT class_id, name FROM users WHERE email=?", (email,))
        row = cursor.fetchone()
        current_user["class_id"] = row[0] if row else None
        user_name = row[1] if row else email
        conn.close()

        # Set visibility based on user role
        if current_user["role"] == "teacher":
            return (
                f"👋 Welcome, {user_name}!", 
                gr.update(visible=False), 
                gr.update(visible=True),
                gr.update(selected="teacher_tab" if current_user["role"] == "teacher" else "student_tab")
            )
        else:
            return (
                f"👋 Welcome, {user_name}!",
                gr.update(visible=False), 
                gr.update(visible=True),
                gr.update(selected="student_tab")
            )
    else:
        return message, gr.update(visible=True), gr.update(visible=False), gr.update()

def logout():
    # Reset user data
    current_user["email"] = None
    current_user["role"] = None
    current_user["class_id"] = None
    current_user["device_id"] = None
    
    # Show login form, hide dashboard
    return gr.update(visible=True), gr.update(visible=False)

# --- Teacher Dashboard Functions ---
def teacher_dashboard_view():
    if current_user["role"] != "teacher":
        return "Access denied. You are not a teacher."
    
    sessions = get_sessions(current_user["class_id"])
    
    # Format sessions as a list of dictionaries for the DataFrame
    session_data = [
        {"ID": s[0], "Date & Time": s[1], "Status": "🟢 Open" if bool(s[2]) else "🔴 Closed"} 
        for s in sessions
    ]
    
    if not session_data:
        session_data = [{"ID": "-", "Date & Time": "-", "Status": "-"}]
        
    return session_data

def handle_open_session():
    if current_user["role"] != "teacher":
        return "Access denied.", teacher_dashboard_view()
        
    result = toggle_session(current_user["class_id"], True)
    return f"✅ {result}", teacher_dashboard_view()

def handle_close_session():
    if current_user["role"] != "teacher":
        return "Access denied.", teacher_dashboard_view()
        
    result = toggle_session(current_user["class_id"], False)
    return f"❌ {result}", teacher_dashboard_view()

def handle_add_student(name, email, password):
    if not name or not email or not password:
        return "Please fill in all fields."
        
    if current_user["role"] != "teacher":
        return "Access denied. You are not authorized to add students."
        
    result = add_student(name, email, password, current_user["class_id"])
    
    # Clear the form on success
    if "successfully" in result:
        return f"✅ {result}", "", "", ""
    else:
        return f"❌ {result}", gr.update(), gr.update(), gr.update()

# --- Student Dashboard Functions ---
def handle_mark_attendance():
    if current_user["role"] != "student":
        return "Access denied. You are not a student."
    
    session_id = get_open_session(current_user["class_id"])
    
    if not session_id:
        return "❌ No open attendance session right now.", get_student_attendance_data()
    
    if has_marked_attendance(current_user["email"], session_id):
        return "ℹ️ You have already marked attendance for this session.", get_student_attendance_data()
    
    result = mark_attendance(current_user["email"], session_id)
    return f"✅ {result}", get_student_attendance_data()

def get_student_attendance_data():
    if current_user["role"] != "student":
        return [{"Date": "-", "Class": "-"}]
    
    conn = sqlite3.connect("attendance.db")
    cursor = conn.cursor()
    cursor.execute("""
        SELECT s.date, s.class_id
        FROM attendance_logs a
        JOIN sessions s ON a.session_id = s.id
        WHERE a.student_email=?
        ORDER BY s.date DESC
        LIMIT 10
    """, (current_user["email"],))
    records = cursor.fetchall()
    conn.close()
    
    if not records:
        return [{"Date": "-", "Class": "-"}]
    
    return [{"Date": row[0], "Class": row[1]} for row in records]

def get_student_stats():
    if current_user["role"] != "student" or not current_user["email"]:
        return "0", "0%"
    
    conn = sqlite3.connect("attendance.db")
    cursor = conn.cursor()
    
    # Get total sessions for the student's class
    cursor.execute("SELECT COUNT(*) FROM sessions WHERE class_id=?", (current_user["class_id"],))
    total_sessions = cursor.fetchone()[0]
    
    # Get student's attendance count
    cursor.execute("""
        SELECT COUNT(*) FROM attendance_logs a
        JOIN sessions s ON a.session_id = s.id
        WHERE a.student_email=? AND s.class_id=?
    """, (current_user["email"], current_user["class_id"]))
    attended_sessions = cursor.fetchone()[0]
    conn.close()
    
    attendance_percentage = "0%"
    if total_sessions > 0:
        attendance_percentage = f"{(attended_sessions / total_sessions) * 100:.1f}%"
    
    return str(attended_sessions), attendance_percentage

# --- UI Layout ---
with gr.Blocks(theme=theme, title="Smart Attendance System") as demo:
    gr.Markdown(
        """
        # 📱 Smart Attendance System
        ### Modern attendance tracking for educational institutions
        """
    )
    
    # Login Section
    login_container = gr.Column(visible=True)
    with login_container:
        with gr.Group():
            gr.Markdown("### Log in to your account")
            with gr.Row():
                with gr.Column(scale=2):
                    email = gr.Textbox(
                        label="Email Address",
                        placeholder="Enter your email",
                        scale=2
                    )
                    password = gr.Textbox(
                        label="Password",
                        placeholder="Enter your password",
                        type="password", 
                        scale=2
                    )
                    login_msg = gr.Textbox(
                        label="", 
                        interactive=False,
                        visible=True
                    )
                
                with gr.Column(scale=1):
                    gr.Markdown("### Welcome!")
                    gr.Markdown("Sign in to access the attendance system. Teachers can manage sessions and students, while students can mark their attendance.")
            
            with gr.Row():
                login_btn = gr.Button(
                    "🔐 Login", 
                    variant="primary", 
                    scale=1
                )

    # Dashboard Section
    dashboard_container = gr.Column(visible=False)
    with dashboard_container:
        with gr.Row():
            user_greeting = gr.Textbox(
                value="Welcome!", 
                label="", 
                interactive=False
            )
            logout_btn = gr.Button(
                "🚪 Logout", 
                variant="secondary", 
                scale=0
            )
        
        # Tabs for different interfaces
        with gr.Tabs(selected=0) as dashboard_tabs:
            # Teacher Dashboard Tab
            with gr.TabItem("👨‍🏫 Teacher Dashboard", id="teacher_tab"):
                with gr.Row():
                    with gr.Column(scale=2):
                        gr.Markdown("### Class Sessions")
                        with gr.Row():
                            open_btn = gr.Button("✅ Open Session", variant="primary")
                            close_btn = gr.Button("❌ Close Session", variant="secondary")
                        
                        session_status = gr.Textbox(label="", interactive=False)
                        
                        gr.Markdown("### Session History")
                        refresh_btn = gr.Button("🔄 Refresh Sessions", variant="secondary")
                        session_output = gr.DataFrame(
                            headers=["ID", "Date & Time", "Status"],
                            datatype=["number", "str", "str"],
                            label="All Sessions"
                        )
                    
                    with gr.Column(scale=1):
                        gr.Markdown("### Add New Student")
                        with gr.Group():
                            student_name = gr.Textbox(
                                label="Student Name",
                                placeholder="Full name"
                            )
                            student_email = gr.Textbox(
                                label="Student Email",
                                placeholder="student@example.com"
                            )
                            student_pass = gr.Textbox(
                                label="Password",
                                placeholder="Create password",
                                type="password"
                            )
                            add_btn = gr.Button("➕ Add Student", variant="primary")
                            add_status = gr.Textbox(label="", interactive=False)
            
            # Student Dashboard Tab
            with gr.TabItem("👨‍🎓 Student Dashboard", id="student_tab"):
                with gr.Row():
                    with gr.Column(scale=1):
                        gr.Markdown("### Quick Actions")
                        mark_btn = gr.Button("📍 Mark Attendance", size="lg", variant="primary")
                        mark_status = gr.Textbox(label="Status", interactive=False)
                        
                        gr.Markdown("### Your Statistics")
                        with gr.Row():
                            with gr.Column():
                                total_attended = gr.Textbox(label="Sessions Attended", interactive=False)
                            with gr.Column():
                                attendance_rate = gr.Textbox(label="Attendance Rate", interactive=False)
                    
                    with gr.Column(scale=2):
                        gr.Markdown("### Attendance History")
                        attendance_table = gr.DataFrame(
                            headers=["Date", "Class"],
                            datatype=["str", "str"],
                            label="Your Recent Attendance",
                            interactive=False
                        )

    # Event Bindings
    login_btn.click(
        fn=login, 
        inputs=[email, password], 
        outputs=[user_greeting, login_container, dashboard_container, dashboard_tabs]
    )
    
    logout_btn.click(
        fn=logout,
        outputs=[login_container, dashboard_container]
    )
    
    # Teacher functions
    refresh_btn.click(
        fn=teacher_dashboard_view, 
        outputs=session_output
    )
    
    open_btn.click(
        fn=handle_open_session, 
        outputs=[session_status, session_output]
    )
    
    close_btn.click(
        fn=handle_close_session, 
        outputs=[session_status, session_output]
    )
    
    add_btn.click(
        fn=handle_add_student, 
        inputs=[student_name, student_email, student_pass], 
        outputs=[add_status, student_name, student_email, student_pass]
    )
    
    # Student functions
    mark_btn.click(
        fn=handle_mark_attendance, 
        outputs=[mark_status, attendance_table]
    )
    
    # Dynamic loading handlers
    dashboard_tabs.select(
        fn=lambda tab: teacher_dashboard_view() if tab == "teacher_tab" else get_student_attendance_data(),
        inputs=dashboard_tabs,
        outputs=session_output if dashboard_tabs.selected == "teacher_tab" else attendance_table
    )
    
    dashboard_tabs.select(
        fn=lambda tab: get_student_stats() if tab == "student_tab" else (None, None),
        inputs=dashboard_tabs,
        outputs=[total_attended, attendance_rate]
    )

    # Footer
    gr.Markdown(
        """
        ---
        ### Smart Attendance - A modern attendance tracking solution
        Version 2.0 | © 2025
        """
    )

# Launch the app
if __name__ == "__main__":
    demo.launch(share=True)