//
//  AppLocalization.swift
//  App for Indeed
//
//  English-first localization using Localizable.strings (same pattern as the LinkedIn app).
//  Add more locales by creating `<locale>.lproj/Localizable.strings` and extending AppLanguage.
//

import Foundation

enum AppLanguage: CaseIterable {
    case english
    case frenchCanada
    case french
    case arabic
    case chineseSimplified
    case chineseTraditional

    var localeIdentifier: String {
        switch self {
        case .english:
            return "en"
        case .frenchCanada:
            return "fr-CA"
        case .french:
            return "fr"
        case .arabic:
            return "ar"
        case .chineseSimplified:
            return "zh-Hans"
        case .chineseTraditional:
            return "zh-Hant"
        }
    }

    static var systemLanguage: AppLanguage {
        let preferred = Locale.preferredLanguages.first ?? "en"
        let lower = preferred.lowercased()
        if lower.hasPrefix("zh-hant")
            || lower.hasPrefix("zh-tw")
            || lower.hasPrefix("zh-hk")
            || lower.hasPrefix("zh-mo")
            || lower.contains("-hant") {
            return .chineseTraditional
        }
        if lower.hasPrefix("zh") {
            return .chineseSimplified
        }
        if lower.hasPrefix("fr-ca") {
            return .frenchCanada
        }
        if lower.hasPrefix("fr") {
            return .french
        }
        for language in AppLanguage.allCases where preferred.hasPrefix(language.localeIdentifier) {
            return language
        }
        return .english
    }

    /// Settings language picker labels — fixed English names, not localized.
    var localizedDisplayName: String {
        switch self {
        case .english:
            return "English"
        case .frenchCanada:
            return "French (Canada)"
        case .french:
            return "French"
        case .arabic:
            return "Arabic"
        case .chineseSimplified:
            return "Chinese (Simplified)"
        case .chineseTraditional:
            return "Chinese (Traditional)"
        }
    }
}

func appLocalized(_ key: String, language: AppLanguage) -> String {
    guard let path = Bundle.main.path(forResource: language.localeIdentifier, ofType: "lproj"),
          let bundle = Bundle(path: path) else {
        return key
    }
    return bundle.localizedString(forKey: key, value: key, table: nil)
}

func currentAppLanguage() -> AppLanguage {
    let code = UserDefaults.standard.string(forKey: "com.appforindeed.preferredLanguage") ?? "en"
    return AppLanguage.allCases.first(where: { $0.localeIdentifier == code }) ?? .english
}

/// Resolves copy for the user’s currently selected language.
func L(_ key: String) -> String {
    appLocalized(key, language: currentAppLanguage())
}

/// Localized CV template title. Built-in templates use English keys in `Localizable.strings`;
/// AI-generated titles fall back to per-word translation when no exact key exists.
func localizedTemplateName(_ nameKey: String) -> String {
    let language = currentAppLanguage()
    let trimmed = nameKey.trimmingCharacters(in: .whitespacesAndNewlines)
    guard !trimmed.isEmpty else { return nameKey }

    let exact = appLocalized(trimmed, language: language)
    if exact != trimmed { return exact }

    guard language != .english else { return trimmed }
    return translateTemplateNameByTokens(trimmed, language: language)
}

private func translateTemplateNameByTokens(_ name: String, language: AppLanguage) -> String {
    let tokens = name.split(separator: " ").map(String.init)
    guard !tokens.isEmpty else { return name }

    let translated = tokens.map { token -> String in
        let perWord = appLocalized(token, language: language)
        if perWord != token { return perWord }
        return templateNameTokenTranslation(token, language: language) ?? token
    }

    switch language {
    case .chineseSimplified, .chineseTraditional:
        return translated.joined()
    case .arabic, .english, .french, .frenchCanada:
        return translated.joined(separator: " ")
    }
}

/// Vocabulary for AI-invented template titles (e.g. “Creative Cascade”) when no full-string key exists.
private func templateNameTokenTranslation(_ token: String, language: AppLanguage) -> String? {
    let key = token.trimmingCharacters(in: .whitespacesAndNewlines)
    guard !key.isEmpty else { return nil }

    switch language {
    case .chineseTraditional:
        return TemplateNameTokenLexicon.zhHant[key] ?? TemplateNameTokenLexicon.zhHant[key.capitalized]
    case .chineseSimplified:
        return TemplateNameTokenLexicon.zhHans[key] ?? TemplateNameTokenLexicon.zhHans[key.capitalized]
    case .arabic:
        return TemplateNameTokenLexicon.ar[key] ?? TemplateNameTokenLexicon.ar[key.capitalized]
    case .french, .frenchCanada, .english:
        return nil
    }
}

private enum TemplateNameTokenLexicon {
    static let zhHant: [String: String] = [
        "AI": "人工智慧", "UI": "介面", "UX": "體驗", "ATS": "ATS",
        "Airy": "通透", "Atlas": "地圖", "Axis": "軸線", "Bloom": "綻放",
        "Blue": "藍", "Bold": "大膽", "Briefing": "簡報", "Cascade": "層疊",
        "Chairman": "主席", "Charter": "憲章", "Circuit": "電路", "Clear": "清晰",
        "Conduit": "管道", "Core": "核心", "Corporate": "企業", "Craft": "工藝",
        "Creative": "創意", "Design": "設計", "Docket": "待辦", "Dynamo": "動力",
        "Echo": "回音", "Edge": "邊緣", "Ember": "餘燼", "Estate": "莊園",
        "Executive": "高階", "Facet": "刻面", "Flow": "流動", "Flux": "流變",
        "Forge": "鍛造", "Frame": "框架", "Grid": "網格", "Harbor": "港灣",
        "Horizon": "地平線", "Impact": "影響", "Kite": "風箏", "Lattice": "格柵",
        "Ledger": "帳本", "Lens": "鏡頭", "Linea": "線條", "Marigold": "金盞花",
        "Mesh": "網狀", "Minimal": "簡約", "Modern": "現代", "Mono": "單色",
        "Monarch": "君主", "Nova": "新星", "North": "北方", "Ocean": "海洋",
        "Path": "路徑", "Peak": "峰", "Pixel": "像素", "Pinstripe": "細條紋",
        "Prime": "首要", "Prism": "稜鏡", "Professional": "專業", "Pulse": "脈動",
        "Pure": "純淨", "Quorum": "法定人數", "Regent": "攝政", "River": "河",
        "Sculptor": "雕刻", "Shift": "轉換", "Slate": "石板", "Spark": "火花",
        "Sterling": "純正", "Stone": "石", "Studio": "工作室", "Summit": "頂峰",
        "Swiss": "瑞士", "Swift": "迅捷", "Tabular": "表格", "Vale": "谷",
        "Vertex": "頂點", "Wave": "波浪", "White": "白"
    ]

    static let zhHans: [String: String] = [
        "AI": "人工智能", "UI": "界面", "UX": "体验", "ATS": "ATS",
        "Airy": "通透", "Atlas": "地图", "Axis": "轴线", "Bloom": "绽放",
        "Blue": "蓝", "Bold": "大胆", "Briefing": "简报", "Cascade": "层叠",
        "Chairman": "主席", "Charter": "宪章", "Circuit": "电路", "Clear": "清晰",
        "Conduit": "管道", "Core": "核心", "Corporate": "企业", "Craft": "工艺",
        "Creative": "创意", "Design": "设计", "Docket": "待办", "Dynamo": "动力",
        "Echo": "回音", "Edge": "边缘", "Ember": "余烬", "Estate": "庄园",
        "Executive": "高管", "Facet": "刻面", "Flow": "流动", "Flux": "流变",
        "Forge": "锻造", "Frame": "框架", "Grid": "网格", "Harbor": "港湾",
        "Horizon": "地平线", "Impact": "影响", "Kite": "风筝", "Lattice": "格栅",
        "Ledger": "账本", "Lens": "镜头", "Linea": "线条", "Marigold": "金盏花",
        "Mesh": "网状", "Minimal": "简约", "Modern": "现代", "Mono": "单色",
        "Monarch": "君主", "Nova": "新星", "North": "北方", "Ocean": "海洋",
        "Path": "路径", "Peak": "峰", "Pixel": "像素", "Pinstripe": "细条纹",
        "Prime": "首要", "Prism": "棱镜", "Professional": "专业", "Pulse": "脉动",
        "Pure": "纯净", "Quorum": "法定人数", "Regent": "摄政", "River": "河",
        "Sculptor": "雕刻", "Shift": "转换", "Slate": "石板", "Spark": "火花",
        "Sterling": "纯正", "Stone": "石", "Studio": "工作室", "Summit": "顶峰",
        "Swiss": "瑞士", "Swift": "迅捷", "Tabular": "表格", "Vale": "谷",
        "Vertex": "顶点", "Wave": "波浪", "White": "白"
    ]

    static let ar: [String: String] = [
        "Creative": "إبداعي", "Cascade": "تتالي", "Design": "تصميم", "Dynamo": "ديناميكي",
        "Modern": "عصري", "Professional": "احترافي", "Executive": "تنفيذي", "Minimal": "بسيط",
        "Ocean": "محيط", "Blue": "أزرق", "Summit": "قمة", "Horizon": "أفق", "Harbor": "ميناء",
        "Studio": "استوديو", "Craft": "حرفة", "Sculptor": "نحات", "UI": "واجهة"
    ]
}


@MainActor
final class AppLanguageManager {
    static let shared = AppLanguageManager()

    static let didChangeNotification = Notification.Name("AppLanguageManager.didChange")

    private enum UserDefaultsKey {
        static let preferredLanguage = "com.appforindeed.preferredLanguage"
    }

    var current: AppLanguage {
        currentAppLanguage()
    }

    func applyStoredPreferenceOnLaunch() {
        // UI copy uses `appLocalized`; do not drive layout from `AppleLanguages` (Arabic forces RTL and breaks CV templates).
        UserDefaults.standard.removeObject(forKey: "AppleLanguages")
        if UserDefaults.standard.string(forKey: UserDefaultsKey.preferredLanguage) == nil {
            setLanguage(AppLanguage.systemLanguage, notify: false)
        }
    }

    func setLanguage(_ language: AppLanguage, notify: Bool = true) {
        let code = language.localeIdentifier
        UserDefaults.standard.set(code, forKey: UserDefaultsKey.preferredLanguage)
        UserDefaults.standard.removeObject(forKey: "AppleLanguages")
        if notify {
            NotificationCenter.default.post(name: Self.didChangeNotification, object: self)
        }
    }

    func setLanguage(code: String, notify: Bool = true) {
        guard let language = AppLanguage.allCases.first(where: { $0.localeIdentifier == code }) else { return }
        setLanguage(language, notify: notify)
    }
}