//
//  KBLocalizationManager.m
//  多语言管理实现
//

#import "KBLocalizationManager.h"
#import <Security/Security.h>
#import "KBConfig.h"

// Darwin 跨进程通知：语言变更（App <-> 扩展）
static NSString * const kKBDarwinLocalizationChanged = @"com.loveKey.nyx.loc.changed";

/// 语言常量定义
KBLanguageCode const KBLanguageCodeEnglish           = @"en";
KBLanguageCode const KBLanguageCodeTraditionalChinese = @"zh-Hant";
KBLanguageCode const KBLanguageCodeSpanish           = @"es";
KBLanguageCode const KBLanguageCodePortuguese        = @"pt-PT";
KBLanguageCode const KBLanguageCodeIndonesian        = @"id";

/// 默认支持语言列表（集中配置）
NSArray<KBLanguageCode> *KBDefaultSupportedLanguageCodes(void) {
    static NSArray<KBLanguageCode> *codes;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        codes = @[
            KBLanguageCodeEnglish,
            KBLanguageCodeSpanish,
            KBLanguageCodeIndonesian,
            KBLanguageCodePortuguese,
            KBLanguageCodeTraditionalChinese
        ];
    });
    return codes;
}

/// 语言变更通知名称
NSString * const KBLocalizationDidChangeNotification = @"KBLocalizationDidChangeNotification";

// 通过共享钥匙串跨 Target 持久化语言选择
static NSString * const kKBLocService = @"com.loveKey.nyx.loc";
static NSString * const kKBLocAccount = @"lang"; // 保存 UTF8 的语言代码

// 首次安装/首次启动标记（仅主 App 侧使用标准 UserDefaults；卸载后会被清除，用于抵消 Keychain 在卸载重装后仍保留的问题）
static NSString * const kKBLocDidLaunchKey = @"com.loveKey.nyx.loc.did_launch";
// 主 App 启动标记（存 App Group，键盘扩展可读）：用于“扩展先启动”场景下避免读取卸载重装遗留的 Keychain 语言。
static NSString * const kKBLocAppBootstrappedKey = @"com.loveKey.nyx.loc.app_bootstrapped";
// 用户是否在 App 内手动选择过语言（存 App Group；卸载重装会清理，满足“重装后跟随系统”）
static NSString * const kKBLocUserSelectedLanguageKey = @"com.loveKey.nyx.loc.user_selected_language";

@interface KBLocalizationManager ()
@property (nonatomic, copy, readwrite) KBLanguageCode currentLanguageCode; // 当前语言代码
@property (nonatomic, strong) NSBundle *langBundle; // 对应语言的 .lproj 资源包

- (NSString *)normalizeLanguageCode:(NSString *)code;
- (NSString *)supportedLanguageCodeForCandidate:(nullable NSString *)code;
- (void)kb_onSystemLocaleMaybeChanged:(NSNotification *)note;
@end

// 避免 +shared 初始化阶段递归触发自身：
// 这里提供一个 C 级别的工具函数，构建钥匙串查询，不依赖实例或 +shared。
static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
    NSMutableDictionary *q = [@{ (__bridge id)kSecClass: (__bridge id)kSecClassGenericPassword,
                                 (__bridge id)kSecAttrService: kKBLocService,
                                 (__bridge id)kSecAttrAccount: kKBLocAccount } mutableCopy];
    if (KB_KEYCHAIN_ACCESS_GROUP.length > 0) {
        q[(__bridge id)kSecAttrAccessGroup] = KB_KEYCHAIN_ACCESS_GROUP;
    }
    return q;
}

static void KBLocDarwinCallback(CFNotificationCenterRef center,
                                void *observer,
                                CFStringRef name,
                                const void *object,
                                CFDictionaryRef userInfo) {
    // 语言更新后，扩展侧需要主动 reload；App 侧收到也无害（会被 resolved==current short-circuit）。
    dispatch_async(dispatch_get_main_queue(), ^{
        KBLocalizationManager *m = [KBLocalizationManager shared];
        [m reloadFromSharedStorageIfNeeded];
    });
}

@implementation KBLocalizationManager

/// 是否运行在 App Extension（如键盘扩展）里。
/// 说明：扩展与主 App 共享 Keychain，但不应参与“首次启动”判定，避免扩展抢先写入标记导致主 App 不再清理历史 Keychain。
+ (BOOL)kb_isRunningInAppExtension {
    return ([[NSBundle mainBundle] objectForInfoDictionaryKey:@"NSExtension"] != nil);
}

+ (NSUserDefaults *)kb_appGroupUserDefaults {
    NSUserDefaults *ud = [[NSUserDefaults alloc] initWithSuiteName:AppGroup];
    return ud ?: [NSUserDefaults standardUserDefaults];
}

+ (BOOL)kb_isAppBootstrapped {
    // App Group 在卸载重装后会被清理；扩展通过该标记判断“主 App 是否已在本次安装中启动过”。
    return [[self kb_appGroupUserDefaults] boolForKey:kKBLocAppBootstrappedKey];
}

+ (void)kb_markAppBootstrappedIfNeeded {
    NSUserDefaults *ud = [self kb_appGroupUserDefaults];
    if ([ud boolForKey:kKBLocAppBootstrappedKey]) { return; }
    [ud setBool:YES forKey:kKBLocAppBootstrappedKey];
    [ud synchronize];
}

+ (BOOL)kb_userDidSelectLanguage {
    NSUserDefaults *ud = [self kb_appGroupUserDefaults];
    return [ud boolForKey:kKBLocUserSelectedLanguageKey];
}

+ (void)kb_setUserDidSelectLanguage:(BOOL)selected {
    NSUserDefaults *ud = [self kb_appGroupUserDefaults];
    [ud setBool:selected forKey:kKBLocUserSelectedLanguageKey];
    [ud synchronize];
}

+ (instancetype)shared {
    static KBLocalizationManager *m; static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{
        m = [KBLocalizationManager new];
        // 默认支持语言；可在启动时由外部重置
        m.supportedLanguageCodes = KBDefaultSupportedLanguageCodes();
        
        BOOL isAppExtension = [[self class] kb_isRunningInAppExtension];
        BOOL wasAppBootstrapped = [[self class] kb_isAppBootstrapped];
        BOOL isAppBootstrapped = wasAppBootstrapped;
        if (!isAppExtension) {
            // 仅主 App 写入该标记；扩展只读取
            [[self class] kb_markAppBootstrappedIfNeeded];
            isAppBootstrapped = YES;
        }
        // 新安装判定（优先使用 App Group 标记）：卸载重装后 App Group 会被清理，但 Keychain 可能仍残留。
        // 仅主 App 在检测到“本次安装从未启动过”时清理 Keychain，并写入系统择优结果，供扩展读取。
        BOOL isFreshInstall = (!isAppExtension && !wasAppBootstrapped);
        if (isFreshInstall) {
            [[self class] kc_write:nil];
            // 新安装：确保“未手动选择”状态（App Group 卸载重装会清理，这里再兜底一次）
            [[self class] kb_setUserDidSelectLanguage:NO];
        }
        
        // 兼容旧逻辑：仍保留标准 UserDefaults 的首次启动标记（仅主 App），但不再作为关键判定条件。
        BOOL isFirstLaunch = (!isAppExtension) ? [[self class] kb_markLaunchedAndReturnIsFirstLaunch] : NO;

        // 语言选择策略（满足产品规则）：
        // 1) 用户在 App 内手动选过语言 -> 锁定（不跟随系统）；通过 Keychain 跨 Target 同步
        // 2) 用户未手动选择过 -> 跟随系统当前语言（首选列表第一个），不读取/不写入 Keychain
        BOOL userSelected = [[self class] kb_userDidSelectLanguage];
        NSString *saved = nil;
        if (userSelected) {
            // 扩展在“主 App 尚未启动过”的场景下，忽略 Keychain（防止卸载重装遗留旧值在扩展先启动时生效）
            if (!(isAppExtension && !isAppBootstrapped)) {
                saved = (isFreshInstall ? nil : [[self class] kc_read]);
            }
        } else {
            // 未手动选择：清理可能遗留的 Keychain（例如旧版本曾写入“系统默认”导致后续不再跟随系统）
            if (!isAppExtension) {
                NSString *legacy = [[self class] kc_read];
                if (legacy.length > 0) {
                    [[self class] kc_write:nil];
                }
            }
        }
#if DEBUG
        NSLog(@"[KBLoc] init bundle=%@ isExt=%d appBoot=%d wasBoot=%d fresh=%d firstLaunch=%d userSelected=%d preferred=%@ keychainSaved=%@ supported=%@",
              NSBundle.mainBundle.bundleIdentifier ?: @"",
              isAppExtension, isAppBootstrapped, wasAppBootstrapped, isFreshInstall, isFirstLaunch,
              userSelected,
              [NSLocale preferredLanguages],
              saved ?: @"(nil)",
              m.supportedLanguageCodes ?: @[]);
#endif
        // 计算最终语言：优先手动选择；否则跟随系统当前语言（不在 5 种内则英文）
        NSString *resolved = [m supportedLanguageCodeForCandidate:saved];
        if (saved.length > 0 && resolved.length == 0) {
            // 若保存了不支持的语言码（历史遗留），视为“未手动选择”，清理并回退系统
            [[self class] kc_write:nil];
            [[self class] kb_setUserDidSelectLanguage:NO];
            saved = nil;
            resolved = @"";
        }
        if (resolved.length == 0) {
            resolved = [m bestSupportedLanguageForPreferred:[NSLocale preferredLanguages]] ?: KBLanguageCodeEnglish;
        }
        [m applyLanguage:resolved];
#if DEBUG
        NSLog(@"[KBLoc] resolved=%@ current=%@ bundle=%@",
              resolved ?: @"",
              m.currentLanguageCode ?: @"",
              m.langBundle.bundlePath ?: @"");
#endif

        // 监听 Darwin 跨进程通知（语言变更），用于“App 内切语言 -> 立即刷新键盘”。
        CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(),
                                        (__bridge const void *)(m),
                                        KBLocDarwinCallback,
                                        (__bridge CFStringRef)kKBDarwinLocalizationChanged,
                                        NULL,
                                        CFNotificationSuspensionBehaviorDeliverImmediately);

        // 系统语言/地区变化：如果未手动锁定语言，则跟随系统刷新
        [[NSNotificationCenter defaultCenter] addObserver:m
                                                 selector:@selector(kb_onSystemLocaleMaybeChanged:)
                                                     name:NSCurrentLocaleDidChangeNotification
                                                   object:nil];
    });
    return m;
}

#pragma mark - 对外 API

- (void)setSupportedLanguageCodes:(NSArray<NSString *> *)supportedLanguageCodes {
    // 归一化：去重、去空
    NSMutableOrderedSet *set = [NSMutableOrderedSet orderedSet];
    for (NSString *c in supportedLanguageCodes) {
        if (c.length) { [set addObject:c]; }
    }
    _supportedLanguageCodes = set.array.count ? (NSArray<KBLanguageCode> *)set.array : @[ KBLanguageCodeEnglish ];
    // 若当前语言不再受支持，则按最佳匹配切回（不持久化，仅内存），并广播变更
    if (self.currentLanguageCode.length && ![set containsObject:self.currentLanguageCode]) {
        NSString *best = [self bestSupportedLanguageForPreferred:@[self.currentLanguageCode]];
        [self applyLanguage:best ?: _supportedLanguageCodes.firstObject];
        [[NSNotificationCenter defaultCenter] postNotificationName:KBLocalizationDidChangeNotification object:nil];
    }
}

- (void)setCurrentLanguageCode:(NSString *)code persist:(BOOL)persist {
    if (code.length == 0) return;                     // 忽略空值
    // 仅允许切到“受支持语言”；不支持（如 zh-Hans）时按最佳匹配回退（默认 en）
    NSString *resolved = [self supportedLanguageCodeForCandidate:code];
    if (resolved.length == 0) {
        resolved = [self bestSupportedLanguageForPreferred:@[code]] ?: (self.supportedLanguageCodes.firstObject ?: KBLanguageCodeEnglish);
    }
    if ([resolved isEqualToString:self.currentLanguageCode]) return; // 无变更
    [self applyLanguage:resolved];
    if (persist) {
        [[self class] kb_setUserDidSelectLanguage:YES];
        [[self class] kc_write:self.currentLanguageCode]; // 需同步到 App/扩展
        // 通知对端进程刷新语言（特别是键盘扩展正在显示时）
        CFNotificationCenterPostNotification(CFNotificationCenterGetDarwinNotifyCenter(),
                                             (__bridge CFStringRef)kKBDarwinLocalizationChanged,
                                             NULL, NULL, true);
    }
    [[NSNotificationCenter defaultCenter] postNotificationName:KBLocalizationDidChangeNotification object:nil];
}

- (void)resetToSystemLanguage {
    [[self class] kb_setUserDidSelectLanguage:NO];
    [[self class] kc_write:nil];
    NSString *best = [self bestSupportedLanguageForPreferred:[NSLocale preferredLanguages]] ?: KBLanguageCodeEnglish;
    if ([best isEqualToString:self.currentLanguageCode]) {
        return;
    }
    [self applyLanguage:best];
    // 通知对端进程刷新语言（特别是键盘扩展正在显示时）
    CFNotificationCenterPostNotification(CFNotificationCenterGetDarwinNotifyCenter(),
                                         (__bridge CFStringRef)kKBDarwinLocalizationChanged,
                                         NULL, NULL, true);
    [[NSNotificationCenter defaultCenter] postNotificationName:KBLocalizationDidChangeNotification object:nil];
}

- (NSString *)localizedStringForKey:(NSString *)key {
    return [self localizedStringForKey:key table:nil value:key];
}

- (NSString *)localizedStringForKey:(NSString *)key table:(NSString *)table value:(NSString *)value {
    if (key.length == 0) return @"";
    NSBundle *bundle = self.langBundle ?: NSBundle.mainBundle;
    NSString *tbl = table ?: @"Localizable";
    // 使用 bundle API，避免 NSLocalizedString 被系统语言钉死
    NSString *str = [bundle localizedStringForKey:key value:value table:tbl];
    return str ?: (value ?: key);
}

- (NSString *)bestSupportedLanguageForPreferred:(NSArray<NSString *> *)preferred {
    if (self.supportedLanguageCodes.count == 0) return KBLanguageCodeEnglish;
    // 需求：只使用“系统当前语言”（首选语言列表的第一个）。
    // 若当前语言不在项目支持的 5 种语言内，则回退英文；不要从后续备选语言里再挑一个支持语言。
    NSString *primary = preferred.firstObject ?: @"";
    if (primary.length == 0) {
        for (NSString *s in self.supportedLanguageCodes) {
            if ([s.lowercaseString isEqualToString:@"en"]) { return s; }
        }
        return self.supportedLanguageCodes.firstObject ?: KBLanguageCodeEnglish;
    }
    NSArray<NSString *> *primaryOnly = @[ primary ];
    // 1) 完全匹配
    for (NSString *p in primaryOnly) {
        NSString *pLC = p.lowercaseString;
        for (NSString *s in self.supportedLanguageCodes) {
            if ([pLC isEqualToString:s.lowercaseString]) { return s; }
        }
    }
    // 2) 前缀匹配：如 en-GB -> en, es-MX -> es
    for (NSString *p in primaryOnly) {
        NSString *pLC = p.lowercaseString;
        for (NSString *s in self.supportedLanguageCodes) {
            NSString *sLC = s.lowercaseString;
            if ([pLC hasPrefix:[sLC stringByAppendingString:@"-"]] || [pLC hasPrefix:[sLC stringByAppendingString:@"_"]]) {
                return s;
            }
            // also allow reverse: when supported is regional (rare)
            if ([sLC hasPrefix:[pLC stringByAppendingString:@"-"]] || [sLC hasPrefix:[pLC stringByAppendingString:@"_"]]) {
                return s;
            }
        }
    }
    // 2.5) 特殊处理葡语：pt-BR / pt-PT / pt -> pt-PT（若受支持）
    for (NSString *p in primaryOnly) {
        NSString *pLC = p.lowercaseString;
        if ([pLC isEqualToString:@"pt"] || [pLC hasPrefix:@"pt-"] || [pLC hasPrefix:@"pt_"]) {
            for (NSString *s in self.supportedLanguageCodes) {
                if ([s.lowercaseString isEqualToString:@"pt-pt"]) { return s; }
            }
        }
    }
    // 3) 特殊处理中文：将 zh-Hant/zh-TW/zh-HK 映射到 zh-Hant（若受支持）
    for (NSString *p in primaryOnly) {
        NSString *pLC = p.lowercaseString;
        if ([pLC hasPrefix:@"zh-hant"] || [pLC hasPrefix:@"zh-tw"] || [pLC hasPrefix:@"zh-hk"]) {
            for (NSString *s in self.supportedLanguageCodes) {
                if ([s.lowercaseString isEqualToString:@"zh-hant"]) { return s; }
            }
        }
    }
    // 4) 兜底：若英文受支持则固定回退英文，否则取第一个
    for (NSString *s in self.supportedLanguageCodes) {
        if ([s.lowercaseString isEqualToString:@"en"]) { return s; }
    }
    return self.supportedLanguageCodes.firstObject ?: KBLanguageCodeEnglish;
}

- (NSString *)currentLanguageHeaderValue {
    return self.currentLanguageCode ?: KBLanguageCodeEnglish;
}

#pragma mark - 内部实现

- (NSString *)normalizeLanguageCode:(NSString *)code {
    if (code.length == 0) return @"";
    NSString *normalizedCode = code;
    NSString *lower = normalizedCode.lowercaseString;
    if ([lower isEqualToString:@"pt"] || [lower hasPrefix:@"pt-"] || [lower hasPrefix:@"pt_"]) {
        normalizedCode = @"pt-PT";
    }
    lower = normalizedCode.lowercaseString;
    if ([lower hasPrefix:@"zh-hant"] || [lower hasPrefix:@"zh_hant"] || [lower hasPrefix:@"zh-tw"] || [lower hasPrefix:@"zh_hk"]) {
        normalizedCode = KBLanguageCodeTraditionalChinese;
    }
    return normalizedCode;
}

- (NSString *)supportedLanguageCodeForCandidate:(NSString *)code {
    NSString *normalized = [self normalizeLanguageCode:code];
    if (normalized.length == 0) return @"";
    for (NSString *s in self.supportedLanguageCodes) {
        if ([s.lowercaseString isEqualToString:normalized.lowercaseString]) {
            return s; // 返回“工程内规范码”（保留大小写/连字符风格）
        }
    }
    return @"";
}

- (void)applyLanguage:(NSString *)code {
    NSString *normalizedCode = [self normalizeLanguageCode:code];
    _currentLanguageCode = [normalizedCode copy];
    // 基于当前 Target（App 或扩展）的主 bundle 加载 .lproj 资源
    NSString *path = [NSBundle.mainBundle pathForResource:normalizedCode ofType:@"lproj"];
    if (!path) {
        // 尝试去区域后缀：如 en-GB -> en
        NSString *shortCode = [[normalizedCode componentsSeparatedByCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"-_"]] firstObject];
        if (shortCode.length > 0) {
            path = [NSBundle.mainBundle pathForResource:shortCode ofType:@"lproj"];
        }
    }
    if (path) {
        self.langBundle = [NSBundle bundleWithPath:path];
    } else {
        self.langBundle = NSBundle.mainBundle; // 兜底
    }
}

#pragma mark - 钥匙串读写（App/扩展共享）

+ (BOOL)kb_markLaunchedAndReturnIsFirstLaunch {
    // 注意：这里只能用主 App 自己的标准 UserDefaults。
    // 不要用 App Group，否则键盘扩展可能会抢先写入“已启动”标记，导致主 App 无法在首次启动时清理历史 Keychain。
    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
    if ([ud boolForKey:kKBLocDidLaunchKey]) { return NO; }
    [ud setBool:YES forKey:kKBLocDidLaunchKey];
    [ud synchronize];
    return YES;
}

+ (BOOL)kc_write:(NSString *)lang {
    NSMutableDictionary *q = KBLocBaseKCQuery();
    SecItemDelete((__bridge CFDictionaryRef)q);
    if (lang.length == 0) return YES; // 等价于删除
    NSData *data = [lang dataUsingEncoding:NSUTF8StringEncoding];
    q[(__bridge id)kSecValueData] = data ?: [NSData data];
    q[(__bridge id)kSecAttrAccessible] = (__bridge id)kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly;
    OSStatus st = SecItemAdd((__bridge CFDictionaryRef)q, NULL);
    return (st == errSecSuccess);
}

+ (NSString *)kc_read {
    NSMutableDictionary *q = KBLocBaseKCQuery();
    q[(__bridge id)kSecReturnData] = @YES;
    q[(__bridge id)kSecMatchLimit] = (__bridge id)kSecMatchLimitOne;
    CFTypeRef dataRef = NULL; OSStatus st = SecItemCopyMatching((__bridge CFDictionaryRef)q, &dataRef);
    if (st != errSecSuccess || !dataRef) return nil;
    NSData *data = (__bridge_transfer NSData *)dataRef;
    if (data.length == 0) return nil;
    NSString *lang = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];
    return lang;
}

- (void)kb_onSystemLocaleMaybeChanged:(NSNotification *)note {
    // 只有未手动选择语言时才需要跟随系统变化；手动选择情况下 reload 会优先读取保存值，不会被系统变化影响。
    [self reloadFromSharedStorageIfNeeded];
}

- (void)reloadFromSharedStorageIfNeeded {
    BOOL userSelected = [[self class] kb_userDidSelectLanguage];
    BOOL isAppExtension = [[self class] kb_isRunningInAppExtension];
    BOOL isAppBootstrapped = [[self class] kb_isAppBootstrapped];

    NSString *target = @"";
    if (userSelected) {
        // 扩展在主 App 未启动前：不读取 Keychain（可能遗留旧值），保持当前按系统择优的结果。
        if (isAppExtension && !isAppBootstrapped) {
#if DEBUG
            NSLog(@"[KBLoc] reload skip (app not bootstrapped yet) bundle=%@ current=%@",
                  NSBundle.mainBundle.bundleIdentifier ?: @"",
                  self.currentLanguageCode ?: @"");
#endif
            return;
        }
        NSString *saved = [[self class] kc_read];
        if (saved.length == 0) {
            // 标记为手动选择但无保存值：降级为“跟随系统”
            [[self class] kb_setUserDidSelectLanguage:NO];
        } else {
            NSString *resolved = [self supportedLanguageCodeForCandidate:saved];
            if (resolved.length == 0) {
                // 保存了不支持的语言码（历史遗留）：清理并降级为“跟随系统”
                [[self class] kc_write:nil];
                [[self class] kb_setUserDidSelectLanguage:NO];
            } else {
                target = resolved;
            }
        }
    }

    if (target.length == 0) {
        // 未手动选择：始终按系统当前语言（首选列表第一个）择优
        target = [self bestSupportedLanguageForPreferred:[NSLocale preferredLanguages]] ?: KBLanguageCodeEnglish;
    }

    if ([target isEqualToString:self.currentLanguageCode]) {
        return;
    }

    [self applyLanguage:target];
    // 系统跟随模式：主 App 语言变化时需要通知键盘扩展即时刷新（避免键盘仍停留旧语言）。
    if (!userSelected && !isAppExtension) {
        CFNotificationCenterPostNotification(CFNotificationCenterGetDarwinNotifyCenter(),
                                             (__bridge CFStringRef)kKBDarwinLocalizationChanged,
                                             NULL, NULL, true);
    }
    [[NSNotificationCenter defaultCenter] postNotificationName:KBLocalizationDidChangeNotification object:nil];
}

@end