package tui

import (
    "os"
    "path/filepath"
    "strings"
)

// Lang is the UI language code.
type Lang string

const (
    LangEn Lang = "en"
    LangRu Lang = "ru"
)

// L holds all localizable UI strings.
type L struct {
    // General
    Help       string
    Quit       string
    Cancel     string
    Send       string
    New        string
    Clear      string
    Complete   string
    ScrollMore string
    ScrollClose string
    ScrollPct  string

    // Placeholder & input
    Placeholder string

    // Help overlay
    KeyboardShortcuts string
    InputShortcuts    string
    SlashCommands     string
    SendMessage       string
    NewLineInInput    string
    CycleMode         string
    QuickModelSwitch  string
    CancelStreaming   string
    QuitKeys          string
    ClearScreen       string
    NewConversation   string
    ToggleHelp        string
    ExpandTools       string
    ToggleToolDetails string
    CopyLastResponse  string
    ToggleThinking    string
    ToggleCompact     string
    OpenInEditor      string
    BrowseHistory     string
    ScrollViewport    string
    HalfPageScroll    string
    Autocomplete      string
    AttachFile        string
    ActivateSkill     string
    RunSlashCommand   string
    Language          string
    LanguageF2        string

    // Side panel
    SidePanelAIAgent   string
    SidePanelTagline   string
    SidePanelModels    string
    SidePanelServers   string
    SidePanelICE       string
    SidePanelQuickActions string
    SidePanelHelp      string
    SidePanelHelpDesc  string
    SidePanelServersDesc string
    SidePanelModelDesc string
    SidePanelLoadDesc  string
    SidePanelLoad      string
    ToolsConnected       string
    NoServersConnected   string
    ICEConversations     string
    ICECrossSessionActive string
    ICEDisabled         string
    ICECrossSessionInactive string

    // Model picker
    SelectModel string

    // Modes
    ModeAsk   string
    ModePlan  string
    ModeBuild string

    // Window title
    WindowTitle       string
    WindowTitleThink  string
    WindowTitleStream string
    WindowTitleDone   string

    // Key hints (short action names)
    HintSend    string
    HintComplete string
    HintHelp    string
    HintCancel  string
    HintQuit    string
    HintNew     string
    HintClear   string
    HintCommands string
    HintFiles   string
    HintSkills  string

    // Toasts / messages
    NoModelsAvailable string
    LanguageSet       string
}

var localeEn = L{
    Help: "Help", Quit: "quit", Cancel: "cancel", Send: "send", New: "new", Clear: "clear", Complete: "complete",
    ScrollMore: "↓ scroll for more", ScrollClose: "Esc or q to close", ScrollPct: "%.0f%% · j/k to scroll",
    Placeholder: "Ask anything... (Enter to send, ctrl+b for sidebar)",
    KeyboardShortcuts: "Keyboard Shortcuts",
    InputShortcuts:    "Input Shortcuts",
    SlashCommands:     "Slash Commands",
    SendMessage:       "Send message",
    NewLineInInput:    "New line in input",
    CycleMode:         "Cycle mode (ASK/PLAN/BUILD)",
    QuickModelSwitch:  "Quick model switch",
    CancelStreaming:   "Cancel streaming / close overlay",
    QuitKeys:          "Quit",
    ClearScreen:       "Clear screen (keep history)",
    NewConversation:   "New conversation",
    ToggleHelp:        "Toggle this help (when input empty)",
    ExpandTools:       "Expand/collapse all tools",
    ToggleToolDetails: "Toggle last tool details",
    CopyLastResponse:  "Copy last response",
    ToggleThinking:    "Toggle thinking display",
    ToggleCompact:     "Toggle compact mode",
    OpenInEditor:      "Open input in $EDITOR",
    BrowseHistory:     "Browse input history",
    ScrollViewport:    "Scroll viewport",
    HalfPageScroll:    "Half-page scroll",
    Autocomplete:      "Autocomplete (commands/files/skills)",
    AttachFile:        "Attach file or agent",
    ActivateSkill:     "Activate skill",
    RunSlashCommand:   "Run slash command",
    Language:          "Language",
    LanguageF2:        "Switch interface language (F2)",
    SidePanelAIAgent:   "AI AGENT",
    SidePanelTagline:  "100% local · Your data never leaves",
    SidePanelModels:   "Models",
    SidePanelServers:  "Servers",
    SidePanelICE:      "ICE",
    SidePanelQuickActions: "Quick Actions",
    SidePanelHelp:     "Help",
    SidePanelHelpDesc: "Keyboard shortcuts",
    SidePanelServersDesc: "List connected tools",
    SidePanelModelDesc: "Switch model",
    SidePanelLoad:     "Load",
    SidePanelLoadDesc: "Add context from file",
    ToolsConnected:     "%d tools connected",
    NoServersConnected: "No servers connected",
    ICEConversations:  "%d conversations",
    ICECrossSessionActive: "Cross-session memory active",
    ICEDisabled:        "ICE disabled",
    ICECrossSessionInactive: "Cross-session memory inactive",
    SelectModel:        "Select Model",
    ModeAsk:           "ASK", ModePlan: "PLAN", ModeBuild: "BUILD",
    WindowTitle: "AI AGENT", WindowTitleThink: "AI AGENT · thinking...",
    WindowTitleStream: "AI AGENT · streaming...", WindowTitleDone: "AI AGENT · done",
    HintSend: "send", HintComplete: "complete", HintHelp: "help", HintCancel: "cancel", HintQuit: "quit",
    HintNew: "new", HintClear: "clear", HintCommands: "commands", HintFiles: "files", HintSkills: "skills",
    NoModelsAvailable: "No models available. Check Ollama connection.",
    LanguageSet:       "Language: %s",
}

var localeRu = L{
    Help: "Справка", Quit: "выход", Cancel: "отмена", Send: "отправить", New: "новый", Clear: "очистить", Complete: "дополнение",
    ScrollMore: "↓ листать вниз", ScrollClose: "Esc или q — закрыть", ScrollPct: "%.0f%% · j/k листать",
    Placeholder: "Спросите что угодно... (Enter — отправить, ctrl+b — панель)",
    KeyboardShortcuts: "Горячие клавиши",
    InputShortcuts:    "Клавиши ввода",
    SlashCommands:     "Слэш-команды",
    SendMessage:       "Отправить сообщение",
    NewLineInInput:    "Новая строка в поле ввода",
    CycleMode:         "Режим (ASK/PLAN/BUILD)",
    QuickModelSwitch:  "Быстрая смена модели",
    CancelStreaming:   "Отмена / закрыть окно",
    QuitKeys:          "Выход",
    ClearScreen:       "Очистить экран (история сохраняется)",
    NewConversation:   "Новый диалог",
    ToggleHelp:        "Показать справку (при пустом вводе)",
    ExpandTools:       "Развернуть/свернуть инструменты",
    ToggleToolDetails: "Детали последнего инструмента",
    CopyLastResponse:  "Копировать последний ответ",
    ToggleThinking:   "Показать процесс размышления",
    ToggleCompact:    "Компактный режим",
    OpenInEditor:     "Открыть в $EDITOR",
    BrowseHistory:    "История ввода",
    ScrollViewport:   "Прокрутка",
    HalfPageScroll:   "На полстраницы",
    Autocomplete:     "Дополнение (команды/файлы/навыки)",
    AttachFile:       "Прикрепить файл или агента",
    ActivateSkill:    "Подключить навык",
    RunSlashCommand:  "Выполнить слэш-команду",
    Language:         "Язык",
    LanguageF2:       "Язык интерфейса (F2)",
    SidePanelAIAgent:  "AI AGENT",
    SidePanelTagline:  "100% локально · Ваши данные не покидают устройство",
    SidePanelModels:  "Модели",
    SidePanelServers: "Серверы",
    SidePanelICE:     "ICE",
    SidePanelQuickActions: "Быстрые действия",
    SidePanelHelp:    "Справка",
    SidePanelHelpDesc: "Горячие клавиши",
    SidePanelServersDesc: "Подключённые инструменты",
    SidePanelModelDesc: "Сменить модель",
    SidePanelLoad:    "Загрузить",
    SidePanelLoadDesc: "Добавить контекст из файла",
    ToolsConnected:     "Подключено инструментов: %d",
    NoServersConnected: "Серверы не подключены",
    ICEConversations:   "Диалогов: %d",
    ICECrossSessionActive: "Память между сессиями активна",
    ICEDisabled:        "ICE выключен",
    ICECrossSessionInactive: "Память между сессиями неактивна",
    SelectModel:     "Выбор модели",
    ModeAsk: "ASK", ModePlan: "PLAN", ModeBuild: "BUILD",
    WindowTitle: "AI AGENT", WindowTitleThink: "AI AGENT · думает...",
    WindowTitleStream: "AI AGENT · отвечает...", WindowTitleDone: "AI AGENT · готово",
    HintSend: "отправить", HintComplete: "дополнение", HintHelp: "справка", HintCancel: "отмена", HintQuit: "выход",
    HintNew: "новый", HintClear: "очистить", HintCommands: "команды", HintFiles: "файлы", HintSkills: "навыки",
    NoModelsAvailable: "Нет моделей. Проверьте подключение к Ollama.",
    LanguageSet: "Язык: %s",
}

// Locale returns the strings for the given language. Unknown lang falls back to English.
func Locale(lang Lang) L {
    switch lang {
    case LangRu:
        return localeRu
    default:
        return localeEn
    }
}

// LangName returns a display name for the language.
func LangName(lang Lang) string {
    switch lang {
    case LangRu:
        return "Русский"
    default:
        return "English"
    }
}

// NextLang cycles to the next language (en -> ru -> en).
func NextLang(lang Lang) Lang {
    switch lang {
    case LangEn:
        return LangRu
    case LangRu:
        return LangEn
    default:
        return LangEn
    }
}

// DefaultLangPath returns the path for storing UI language preference.
func DefaultLangPath() string {
    home, err := os.UserHomeDir()
    if err != nil {
        return "lang"
    }
    return filepath.Join(home, ".config", "ai-agent", "lang")
}

// LoadLang reads the saved language from DefaultLangPath(). Returns LangEn if missing or invalid.
func LoadLang() Lang {
    data, err := os.ReadFile(DefaultLangPath())
    if err != nil {
        return LangEn
    }
    switch strings.TrimSpace(strings.ToLower(string(data))) {
    case "ru", "русский":
        return LangRu
    default:
        return LangEn
    }
}

// SaveLang writes the language to DefaultLangPath().
func SaveLang(lang Lang) error {
    path := DefaultLangPath()
    dir := filepath.Dir(path)
    if err := os.MkdirAll(dir, 0o755); err != nil {
        return err
    }
    return os.WriteFile(path, []byte(lang), 0o644)
}