/// Модуль для настраиваемых горячих клавиш
///
/// Поддерживает:
/// - Загрузку из конфигурационного файла
/// - Множественные binding для одной команды (EN/RU раскладки)
/// - Type-safe команды через enum
use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;

/// Команды приложения
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum Command {
    // Navigation
    MoveUp,
    MoveDown,
    MoveLeft,
    MoveRight,
    PageUp,
    PageDown,

    // Global
    Quit,
    OpenSearch,
    OpenSearchInChat,
    Help,

    // Chat list
    OpenChat,
    SelectFolder1,
    SelectFolder2,
    SelectFolder3,
    SelectFolder4,
    SelectFolder5,
    SelectFolder6,
    SelectFolder7,
    SelectFolder8,
    SelectFolder9,

    // Message actions
    EditMessage,
    DeleteMessage,
    ReplyMessage,
    ForwardMessage,
    CopyMessage,
    ReactMessage,
    SelectMessage,

    // Media
    ViewImage, // v - просмотр фото

    // Voice playback
    TogglePlayback, // Space - play/pause
    SeekForward,    // → - seek +5s
    SeekBackward,   // ← - seek -5s

    // Input
    SubmitMessage,
    Cancel,
    NewLine,
    DeleteChar,
    DeleteWord,
    MoveToStart,
    MoveToEnd,

    // Vim mode
    EnterInsertMode,

    // Profile
    OpenProfile,
}

/// Привязка клавиши к команде
#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub struct KeyBinding {
    #[serde(with = "key_code_serde")]
    pub key: KeyCode,
    #[serde(with = "key_modifiers_serde")]
    pub modifiers: KeyModifiers,
}

impl KeyBinding {
    pub fn new(key: KeyCode) -> Self {
        Self { key, modifiers: KeyModifiers::NONE }
    }

    pub fn with_ctrl(key: KeyCode) -> Self {
        Self { key, modifiers: KeyModifiers::CONTROL }
    }

    #[allow(dead_code)]
    pub fn with_shift(key: KeyCode) -> Self {
        Self { key, modifiers: KeyModifiers::SHIFT }
    }

    #[allow(dead_code)]
    pub fn with_alt(key: KeyCode) -> Self {
        Self { key, modifiers: KeyModifiers::ALT }
    }

    pub fn matches(&self, event: &KeyEvent) -> bool {
        self.key == event.code && self.modifiers == event.modifiers
    }
}

/// Конфигурация горячих клавиш
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Keybindings {
    #[serde(flatten)]
    bindings: HashMap<Command, Vec<KeyBinding>>,
}

impl Keybindings {
    /// Ищет команду по клавише
    pub fn get_command(&self, event: &KeyEvent) -> Option<Command> {
        for (command, bindings) in &self.bindings {
            if bindings.iter().any(|binding| binding.matches(event)) {
                return Some(*command);
            }
        }
        None
    }
}

impl Default for Keybindings {
    fn default() -> Self {
        let mut bindings = HashMap::new();

        // Navigation
        bindings.insert(
            Command::MoveUp,
            vec![
                KeyBinding::new(KeyCode::Up),
                KeyBinding::new(KeyCode::Char('k')),
                KeyBinding::new(KeyCode::Char('р')), // RU (custom mapping, not standard ЙЦУКЕН)
            ],
        );
        bindings.insert(
            Command::MoveDown,
            vec![
                KeyBinding::new(KeyCode::Down),
                KeyBinding::new(KeyCode::Char('j')),
                KeyBinding::new(KeyCode::Char('о')), // RU
            ],
        );
        bindings.insert(
            Command::MoveLeft,
            vec![
                KeyBinding::new(KeyCode::Left),
                KeyBinding::new(KeyCode::Char('h')),
                KeyBinding::new(KeyCode::Char('л')), // RU (custom mapping, not standard ЙЦУКЕН)
            ],
        );
        bindings.insert(
            Command::MoveRight,
            vec![
                KeyBinding::new(KeyCode::Right),
                KeyBinding::new(KeyCode::Char('l')),
                KeyBinding::new(KeyCode::Char('д')), // RU
            ],
        );
        bindings.insert(
            Command::PageUp,
            vec![
                KeyBinding::new(KeyCode::PageUp),
                KeyBinding::with_ctrl(KeyCode::Char('u')),
            ],
        );
        bindings.insert(
            Command::PageDown,
            vec![
                KeyBinding::new(KeyCode::PageDown),
                KeyBinding::with_ctrl(KeyCode::Char('d')),
            ],
        );

        // Global
        bindings.insert(
            Command::Quit,
            vec![
                KeyBinding::new(KeyCode::Char('q')),
                KeyBinding::new(KeyCode::Char('й')), // RU
                KeyBinding::with_ctrl(KeyCode::Char('c')),
            ],
        );
        bindings.insert(Command::OpenSearch, vec![KeyBinding::with_ctrl(KeyCode::Char('s'))]);
        bindings.insert(Command::OpenSearchInChat, vec![KeyBinding::with_ctrl(KeyCode::Char('f'))]);
        bindings.insert(Command::Help, vec![KeyBinding::new(KeyCode::Char('?'))]);

        // Chat list
        // Note: Enter обрабатывается через Command::SubmitMessage в handle_enter_key()
        for i in 1..=9 {
            let cmd = match i {
                1 => Command::SelectFolder1,
                2 => Command::SelectFolder2,
                3 => Command::SelectFolder3,
                4 => Command::SelectFolder4,
                5 => Command::SelectFolder5,
                6 => Command::SelectFolder6,
                7 => Command::SelectFolder7,
                8 => Command::SelectFolder8,
                9 => Command::SelectFolder9,
                _ => unreachable!(),
            };
            bindings.insert(
                cmd,
                vec![KeyBinding::new(KeyCode::Char(
                    char::from_digit(i, 10).unwrap(),
                ))],
            );
        }

        // Message actions
        // Note: EditMessage (Up) обрабатывается напрямую в handle_open_chat_keyboard_input
        // в зависимости от контекста (пустой инпут). Не привязываем здесь, чтобы не
        // конфликтовать с Command::MoveUp в списке чатов.
        bindings.insert(
            Command::DeleteMessage,
            vec![
                KeyBinding::new(KeyCode::Delete),
                KeyBinding::new(KeyCode::Char('d')),
                KeyBinding::new(KeyCode::Char('в')), // RU
            ],
        );
        bindings.insert(
            Command::ReplyMessage,
            vec![
                KeyBinding::new(KeyCode::Char('r')),
                KeyBinding::new(KeyCode::Char('к')), // RU
            ],
        );
        bindings.insert(
            Command::ForwardMessage,
            vec![
                KeyBinding::new(KeyCode::Char('f')),
                KeyBinding::new(KeyCode::Char('а')), // RU
            ],
        );
        bindings.insert(
            Command::CopyMessage,
            vec![
                KeyBinding::new(KeyCode::Char('y')),
                KeyBinding::new(KeyCode::Char('н')), // RU
            ],
        );
        bindings.insert(
            Command::ReactMessage,
            vec![
                KeyBinding::new(KeyCode::Char('e')),
                KeyBinding::new(KeyCode::Char('у')), // RU
            ],
        );
        // Note: SelectMessage обрабатывается через Command::SubmitMessage в handle_enter_key()

        // Media
        bindings.insert(
            Command::ViewImage,
            vec![
                KeyBinding::new(KeyCode::Char('v')),
                KeyBinding::new(KeyCode::Char('м')), // RU
            ],
        );

        // Voice playback
        bindings.insert(Command::TogglePlayback, vec![KeyBinding::new(KeyCode::Char(' '))]);
        bindings.insert(Command::SeekForward, vec![KeyBinding::new(KeyCode::Right)]);
        bindings.insert(Command::SeekBackward, vec![KeyBinding::new(KeyCode::Left)]);

        // Input
        bindings.insert(Command::SubmitMessage, vec![KeyBinding::new(KeyCode::Enter)]);
        bindings.insert(Command::Cancel, vec![KeyBinding::new(KeyCode::Esc)]);
        bindings.insert(Command::NewLine, vec![]);
        bindings.insert(Command::DeleteChar, vec![KeyBinding::new(KeyCode::Backspace)]);
        bindings.insert(
            Command::DeleteWord,
            vec![
                KeyBinding::with_ctrl(KeyCode::Backspace),
                KeyBinding::with_ctrl(KeyCode::Char('w')),
            ],
        );
        bindings.insert(
            Command::MoveToStart,
            vec![
                KeyBinding::new(KeyCode::Home),
                KeyBinding::with_ctrl(KeyCode::Char('a')),
            ],
        );
        bindings.insert(
            Command::MoveToEnd,
            vec![
                KeyBinding::new(KeyCode::End),
                KeyBinding::with_ctrl(KeyCode::Char('e')),
            ],
        );

        // Vim mode
        bindings.insert(
            Command::EnterInsertMode,
            vec![
                KeyBinding::new(KeyCode::Char('i')),
                KeyBinding::new(KeyCode::Char('ш')), // RU
            ],
        );

        // Profile
        bindings.insert(
            Command::OpenProfile,
            vec![
                KeyBinding::with_ctrl(KeyCode::Char('u')), // Ctrl+U instead of Ctrl+I
                KeyBinding::with_ctrl(KeyCode::Char('г')), // RU
            ],
        );

        Self { bindings }
    }
}

/// Сериализация KeyModifiers
mod key_modifiers_serde {
    use crossterm::event::KeyModifiers;
    use serde::{Deserialize, Deserializer, Serializer};

    pub fn serialize<S>(modifiers: &KeyModifiers, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        let mut parts = Vec::new();
        if modifiers.contains(KeyModifiers::SHIFT) {
            parts.push("Shift");
        }
        if modifiers.contains(KeyModifiers::CONTROL) {
            parts.push("Ctrl");
        }
        if modifiers.contains(KeyModifiers::ALT) {
            parts.push("Alt");
        }
        if modifiers.contains(KeyModifiers::SUPER) {
            parts.push("Super");
        }
        if modifiers.contains(KeyModifiers::HYPER) {
            parts.push("Hyper");
        }
        if modifiers.contains(KeyModifiers::META) {
            parts.push("Meta");
        }

        if parts.is_empty() {
            serializer.serialize_str("None")
        } else {
            serializer.serialize_str(&parts.join("+"))
        }
    }

    pub fn deserialize<'de, D>(deserializer: D) -> Result<KeyModifiers, D::Error>
    where
        D: Deserializer<'de>,
    {
        let s = String::deserialize(deserializer)?;

        if s == "None" || s.is_empty() {
            return Ok(KeyModifiers::NONE);
        }

        let mut modifiers = KeyModifiers::NONE;
        for part in s.split('+') {
            match part.trim() {
                "Shift" => modifiers |= KeyModifiers::SHIFT,
                "Ctrl" | "Control" => modifiers |= KeyModifiers::CONTROL,
                "Alt" => modifiers |= KeyModifiers::ALT,
                "Super" => modifiers |= KeyModifiers::SUPER,
                "Hyper" => modifiers |= KeyModifiers::HYPER,
                "Meta" => modifiers |= KeyModifiers::META,
                _ => return Err(serde::de::Error::custom(format!("Unknown modifier: {}", part))),
            }
        }

        Ok(modifiers)
    }
}

/// Сериализация KeyCode
mod key_code_serde {
    use crossterm::event::KeyCode;
    use serde::{Deserialize, Deserializer, Serializer};

    pub fn serialize<S>(key: &KeyCode, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        let s = match key {
            KeyCode::Char(c) => format!("Char('{}')", c),
            KeyCode::F(n) => format!("F{}", n),
            KeyCode::Backspace => "Backspace".to_string(),
            KeyCode::Enter => "Enter".to_string(),
            KeyCode::Left => "Left".to_string(),
            KeyCode::Right => "Right".to_string(),
            KeyCode::Up => "Up".to_string(),
            KeyCode::Down => "Down".to_string(),
            KeyCode::Home => "Home".to_string(),
            KeyCode::End => "End".to_string(),
            KeyCode::PageUp => "PageUp".to_string(),
            KeyCode::PageDown => "PageDown".to_string(),
            KeyCode::Tab => "Tab".to_string(),
            KeyCode::BackTab => "BackTab".to_string(),
            KeyCode::Delete => "Delete".to_string(),
            KeyCode::Insert => "Insert".to_string(),
            KeyCode::Esc => "Esc".to_string(),
            _ => "Unknown".to_string(),
        };
        serializer.serialize_str(&s)
    }

    pub fn deserialize<'de, D>(deserializer: D) -> Result<KeyCode, D::Error>
    where
        D: Deserializer<'de>,
    {
        let s = String::deserialize(deserializer)?;

        if s.starts_with("Char('") && s.ends_with("')") {
            let c = s
                .chars()
                .nth(6)
                .ok_or_else(|| serde::de::Error::custom("Invalid Char format"))?;
            return Ok(KeyCode::Char(c));
        }

        if let Some(suffix) = s.strip_prefix("F") {
            let n = suffix.parse().map_err(serde::de::Error::custom)?;
            return Ok(KeyCode::F(n));
        }

        match s.as_str() {
            "Backspace" => Ok(KeyCode::Backspace),
            "Enter" => Ok(KeyCode::Enter),
            "Left" => Ok(KeyCode::Left),
            "Right" => Ok(KeyCode::Right),
            "Up" => Ok(KeyCode::Up),
            "Down" => Ok(KeyCode::Down),
            "Home" => Ok(KeyCode::Home),
            "End" => Ok(KeyCode::End),
            "PageUp" => Ok(KeyCode::PageUp),
            "PageDown" => Ok(KeyCode::PageDown),
            "Tab" => Ok(KeyCode::Tab),
            "BackTab" => Ok(KeyCode::BackTab),
            "Delete" => Ok(KeyCode::Delete),
            "Insert" => Ok(KeyCode::Insert),
            "Esc" => Ok(KeyCode::Esc),
            _ => Err(serde::de::Error::custom(format!("Unknown key: {}", s))),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_default_bindings() {
        let kb = Keybindings::default();

        // Проверяем навигацию
        assert_eq!(kb.get_command(&KeyEvent::from(KeyCode::Up)), Some(Command::MoveUp));
        assert_eq!(kb.get_command(&KeyEvent::from(KeyCode::Char('k'))), Some(Command::MoveUp));
        assert_eq!(kb.get_command(&KeyEvent::from(KeyCode::Char('р'))), Some(Command::MoveUp));
    }

    #[test]
    fn test_get_command() {
        let kb = Keybindings::default();

        let event = KeyEvent::from(KeyCode::Char('q'));
        assert_eq!(kb.get_command(&event), Some(Command::Quit));

        let event = KeyEvent::from(KeyCode::Char('й')); // RU
        assert_eq!(kb.get_command(&event), Some(Command::Quit));
    }

    #[test]
    fn test_ctrl_modifier() {
        let kb = Keybindings::default();

        let mut event = KeyEvent::from(KeyCode::Char('s'));
        event.modifiers = KeyModifiers::CONTROL;

        assert_eq!(kb.get_command(&event), Some(Command::OpenSearch));
    }
}