use std::io;
use std::sync::mpsc;
use std::thread;
use std::time::Duration;
use std::collections::VecDeque;

use application::UseCase;
use crossterm::{
    event::{self, DisableMouseCapture, EnableMouseCapture, Event, KeyCode},
    execute,
    terminal::{disable_raw_mode, enable_raw_mode, EnterAlternateScreen, LeaveAlternateScreen},
};
use domain::{CreateProduct, CreateUser, Product, User};
use ratatui::{
    backend::{Backend, CrosstermBackend},
    layout::{Constraint, Direction, Layout},
    style::{Color, Style},
    widgets::{Block, Borders, List, ListItem, Paragraph, Wrap},
    Frame, Terminal,
};
use textwrap;

const MAX_HISTORY: usize = 100;

pub struct App {
    input: String,
    messages: Vec<String>,
    should_quit: bool,
    command_history: VecDeque<String>,
    history_index: Option<usize>,
    cursor_position: usize,
}

impl App {
    pub fn new() -> Self {
        Self {
            input: String::new(),
            messages: vec!["Welcome to Sharenet CLI!".to_string()],
            should_quit: false,
            command_history: VecDeque::with_capacity(MAX_HISTORY),
            history_index: None,
            cursor_position: 0,
        }
    }

    pub fn add_message(&mut self, message: String) {
        self.messages.push(message);
    }

    pub fn clear_input(&mut self) {
        self.input.clear();
        self.cursor_position = 0;
    }

    pub fn add_to_history(&mut self, command: String) {
        if !command.trim().is_empty() {
            self.command_history.push_front(command);
            if self.command_history.len() > MAX_HISTORY {
                self.command_history.pop_back();
            }
        }
    }

    pub fn move_cursor(&mut self, delta: isize) {
        let new_pos = self.cursor_position as isize + delta;
        if new_pos >= 0 && new_pos <= self.input.len() as isize {
            self.cursor_position = new_pos as usize;
        }
    }

    pub fn insert_char(&mut self, c: char) {
        self.input.insert(self.cursor_position, c);
        self.cursor_position += 1;
    }

    pub fn delete_char(&mut self) {
        if self.cursor_position > 0 {
            self.input.remove(self.cursor_position - 1);
            self.cursor_position -= 1;
        }
    }
}

pub async fn run_tui<U, P>(user_service: U, product_service: P) -> anyhow::Result<()>
where
    U: UseCase<User> + Clone + Send + 'static,
    P: UseCase<Product> + Clone + Send + 'static,
{
    // Setup terminal
    enable_raw_mode()?;
    let mut stdout = io::stdout();
    execute!(stdout, EnterAlternateScreen, EnableMouseCapture)?;
    let backend = CrosstermBackend::new(stdout);
    let mut terminal = Terminal::new(backend)?;

    // Create app and run it
    let app = App::new();
    let res = run_app(&mut terminal, app, user_service, product_service).await;

    // Restore terminal
    disable_raw_mode()?;
    execute!(
        terminal.backend_mut(),
        LeaveAlternateScreen,
        DisableMouseCapture
    )?;
    terminal.show_cursor()?;

    if let Err(err) = res {
        println!("{:?}", err);
    }

    Ok(())
}

async fn run_app<B: Backend, U, P>(
    terminal: &mut Terminal<B>,
    mut app: App,
    user_service: U,
    product_service: P,
) -> anyhow::Result<()>
where
    U: UseCase<User> + Clone + Send + 'static,
    P: UseCase<Product> + Clone + Send + 'static,
{
    let (tx, rx) = mpsc::channel();
    let user_service_clone = user_service.clone();
    let product_service_clone = product_service.clone();

    // Spawn a thread to handle user input
    thread::spawn(move || {
        loop {
            if event::poll(Duration::from_millis(50)).unwrap() {
                if let Event::Key(key) = event::read().unwrap() {
                    tx.send(key).unwrap();
                }
            }
        }
    });

    loop {
        terminal.draw(|f| ui(f, &app))?;

        if let Ok(key) = rx.try_recv() {
            match key.code {
                KeyCode::Char(c) => {
                    app.insert_char(c);
                }
                KeyCode::Backspace => {
                    app.delete_char();
                }
                KeyCode::Left => {
                    app.move_cursor(-1);
                }
                KeyCode::Right => {
                    app.move_cursor(1);
                }
                KeyCode::Up => {
                    if let Some(index) = app.history_index {
                        if index + 1 < app.command_history.len() {
                            app.history_index = Some(index + 1);
                            app.input = app.command_history[index + 1].clone();
                            app.cursor_position = app.input.len();
                        }
                    } else if !app.command_history.is_empty() {
                        app.history_index = Some(0);
                        app.input = app.command_history[0].clone();
                        app.cursor_position = app.input.len();
                    }
                }
                KeyCode::Down => {
                    if let Some(index) = app.history_index {
                        if index > 0 {
                            app.history_index = Some(index - 1);
                            app.input = app.command_history[index - 1].clone();
                            app.cursor_position = app.input.len();
                        } else {
                            app.history_index = None;
                            app.clear_input();
                        }
                    }
                }
                KeyCode::Enter => {
                    let input = app.input.clone();
                    app.add_to_history(input.clone());
                    app.clear_input();
                    app.history_index = None;
                    
                    // Display the command in a distinct color
                    app.add_message(format!("> {}", input));
                    
                    // Handle commands
                    match input.trim() {
                        "exit" => {
                            app.add_message("Goodbye!".to_string());
                            app.should_quit = true;
                        }
                        "help" => {
                            print_help(&mut app);
                        }
                        cmd if cmd.starts_with("user create") => {
                            match parse_user_create(cmd) {
                                Ok((username, email)) => {
                                    match user_service_clone
                                        .create(CreateUser { username, email })
                                        .await
                                    {
                                        Ok(user) => app.add_message(format!("Created user: {:?}", user)),
                                        Err(e) => app.add_message(format!("Error: {}", e)),
                                    }
                                }
                                Err(e) => app.add_message(format!("Error: {}", e)),
                            }
                        }
                        "user list" => {
                            match user_service_clone.list().await {
                                Ok(users) => app.add_message(format!("Users: {:?}", users)),
                                Err(e) => app.add_message(format!("Error: {}", e)),
                            }
                        }
                        cmd if cmd.starts_with("product create") => {
                            match parse_product_create(cmd) {
                                Ok((name, description)) => {
                                    match product_service_clone
                                        .create(CreateProduct { name, description })
                                        .await
                                    {
                                        Ok(product) => app.add_message(format!("Created product: {:?}", product)),
                                        Err(e) => app.add_message(format!("Error: {}", e)),
                                    }
                                }
                                Err(e) => app.add_message(format!("Error: {}", e)),
                            }
                        }
                        "product list" => {
                            match product_service_clone.list().await {
                                Ok(products) => app.add_message(format!("Products: {:?}", products)),
                                Err(e) => app.add_message(format!("Error: {}", e)),
                            }
                        }
                        "" => {}
                        _ => {
                            app.add_message("Unknown command. Type 'help' for available commands.".to_string());
                        }
                    }
                }
                KeyCode::Esc => {
                    app.should_quit = true;
                }
                _ => {}
            }
        }

        if app.should_quit {
            return Ok(());
        }
    }
}

fn print_help(app: &mut App) {
    app.add_message("\nAvailable commands:".to_string());
    app.add_message("  user create -u <username> -e <email>".to_string());
    app.add_message("    Example: user create -u \"john doe\" -e \"john@example.com\"".to_string());
    app.add_message("  user list".to_string());
    app.add_message("  product create -n <name> -d <description>".to_string());
    app.add_message("    Example: product create -n \"My Product\" -d \"A great product description\"".to_string());
    app.add_message("  product list".to_string());
    app.add_message("\nTips:".to_string());
    app.add_message("  - Use quotes for values with spaces".to_string());
    app.add_message("  - Use Up/Down arrows to navigate command history".to_string());
    app.add_message("  - Press Esc to exit".to_string());
    app.add_message("  - Type 'help' to show this message".to_string());
}

fn ui(f: &mut Frame, app: &App) {
    // Create the layout
    let chunks = Layout::default()
        .direction(Direction::Vertical)
        .margin(1)
        .constraints([
            Constraint::Min(1),
            Constraint::Length(3),
        ])
        .split(f.size());

    // Create the messages list with styling and wrapping
    let messages: Vec<ListItem> = app
        .messages
        .iter()
        .flat_map(|msg| {
            let style = if msg.starts_with("Error:") {
                Style::default().fg(Color::Red)
            } else if msg.starts_with("Created") {
                Style::default().fg(Color::Green)
            } else if msg.starts_with(">") {
                Style::default().fg(Color::Cyan)
            } else {
                Style::default()
            };
            
            // Calculate available width for text (accounting for borders and margins)
            let available_width = chunks[0].width.saturating_sub(2) as usize;
            
            // Split message into wrapped lines
            let wrapped_lines = textwrap::wrap(msg, available_width);
            
            // Convert each wrapped line into a ListItem
            wrapped_lines.into_iter().map(move |line| {
                ListItem::new(line.to_string()).style(style)
            })
        })
        .collect();

    let messages = List::new(messages)
        .block(Block::default().title("Messages").borders(Borders::ALL));
    f.render_widget(messages, chunks[0]);

    // Create the input box with cursor and wrapping
    let input = Paragraph::new(app.input.as_str())
        .style(Style::default().fg(Color::Yellow))
        .block(Block::default().title("Input (Press 'Esc' to exit)").borders(Borders::ALL))
        .wrap(Wrap { trim: true });
    f.render_widget(input, chunks[1]);

    // Show cursor
    f.set_cursor(
        chunks[1].x + app.cursor_position as u16 + 1,
        chunks[1].y + 1,
    );
}

fn parse_user_create(cmd: &str) -> anyhow::Result<(String, String)> {
    let parts: Vec<&str> = cmd.split_whitespace().collect();
    if parts.len() < 6 {
        return Err(anyhow::anyhow!(
            "Invalid command format. Use: user create -u <username> -e <email>\nExample: user create -u \"john doe\" -e \"john@example.com\""
        ));
    }
    
    let mut username = None;
    let mut email = None;
    let mut current_arg = None;
    let mut current_value = Vec::new();
    
    // Skip "user create" command
    let mut i = 2;
    while i < parts.len() {
        match parts[i] {
            "-u" => {
                if let Some(arg_type) = current_arg {
                    match arg_type {
                        "username" => username = Some(current_value.join(" ")),
                        "email" => email = Some(current_value.join(" ")),
                        _ => {}
                    }
                }
                current_arg = Some("username");
                current_value.clear();
                i += 1;
            }
            "-e" => {
                if let Some(arg_type) = current_arg {
                    match arg_type {
                        "username" => username = Some(current_value.join(" ")),
                        "email" => email = Some(current_value.join(" ")),
                        _ => {}
                    }
                }
                current_arg = Some("email");
                current_value.clear();
                i += 1;
            }
            _ => {
                if current_arg.is_some() {
                    current_value.push(parts[i].trim_matches('"'));
                }
                i += 1;
            }
        }
    }
    
    // Handle the last argument
    if let Some(arg_type) = current_arg {
        match arg_type {
            "username" => username = Some(current_value.join(" ")),
            "email" => email = Some(current_value.join(" ")),
            _ => {}
        }
    }
    
    match (username, email) {
        (Some(u), Some(e)) if !u.is_empty() && !e.is_empty() => Ok((u, e)),
        _ => Err(anyhow::anyhow!(
            "Invalid command format. Use: user create -u <username> -e <email>\nExample: user create -u \"john doe\" -e \"john@example.com\""
        )),
    }
}

fn parse_product_create(cmd: &str) -> anyhow::Result<(String, String)> {
    let parts: Vec<&str> = cmd.split_whitespace().collect();
    if parts.len() < 6 {
        return Err(anyhow::anyhow!(
            "Invalid command format. Use: product create -n <name> -d <description>\nExample: product create -n \"My Product\" -d \"A great product description\""
        ));
    }
    
    let mut name = None;
    let mut description = None;
    let mut current_arg = None;
    let mut current_value = Vec::new();
    
    // Skip "product create" command
    let mut i = 2;
    while i < parts.len() {
        match parts[i] {
            "-n" => {
                if let Some(arg_type) = current_arg {
                    match arg_type {
                        "name" => name = Some(current_value.join(" ")),
                        "description" => description = Some(current_value.join(" ")),
                        _ => {}
                    }
                }
                current_arg = Some("name");
                current_value.clear();
                i += 1;
            }
            "-d" => {
                if let Some(arg_type) = current_arg {
                    match arg_type {
                        "name" => name = Some(current_value.join(" ")),
                        "description" => description = Some(current_value.join(" ")),
                        _ => {}
                    }
                }
                current_arg = Some("description");
                current_value.clear();
                i += 1;
            }
            _ => {
                if current_arg.is_some() {
                    current_value.push(parts[i].trim_matches('"'));
                }
                i += 1;
            }
        }
    }
    
    // Handle the last argument
    if let Some(arg_type) = current_arg {
        match arg_type {
            "name" => name = Some(current_value.join(" ")),
            "description" => description = Some(current_value.join(" ")),
            _ => {}
        }
    }
    
    match (name, description) {
        (Some(n), Some(d)) if !n.is_empty() && !d.is_empty() => Ok((n, d)),
        _ => Err(anyhow::anyhow!(
            "Invalid command format. Use: product create -n <name> -d <description>\nExample: product create -n \"My Product\" -d \"A great product description\""
        )),
    }
}