/**
 * Tencent is pleased to support the open source community by making QMUI_iOS available.
 * Copyright (C) 2016-2021 THL A29 Limited, a Tencent company. All rights reserved.
 * Licensed under the MIT License (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at
 * http://opensource.org/licenses/MIT
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
 */
//
//  QMUIThemeManager.m
//  QMUIKit
//
//  Created by MoLice on 2019/J/20.
//

#import "QMUIThemeManager.h"
#import "QMUICore.h"
#import "UIView+QMUITheme.h"
#import "UIViewController+QMUITheme.h"
#import "QMUIThemePrivate.h"
#import "UITraitCollection+QMUI.h"

NSString *const QMUIThemeDidChangeNotification = @"QMUIThemeDidChangeNotification";

@interface QMUIThemeManager ()

@property(nonatomic, strong) NSMutableArray<NSObject<NSCopying> *> *_themeIdentifiers;
@property(nonatomic, strong) NSMutableArray<NSObject *> *_themes;
@end

@implementation QMUIThemeManager

- (void)dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (NSString *)description {
    return [NSString stringWithFormat:@"%@, name = %@, themes = %@", [super description], self.name, self.themes];
}

// 这个方法的声明放在 QMUIThemeManagerCenter.m 里，简单实现 private 的效果
- (instancetype)initWithName:(__kindof NSObject<NSCopying> *)name {
    if (self = [super init]) {
        _name = name;
        self._themeIdentifiers = NSMutableArray.new;
        self._themes = NSMutableArray.new;
        if (@available(iOS 13.0, *)) {
            [UITraitCollection qmui_addUserInterfaceStyleWillChangeObserver:self selector:@selector(handleUserInterfaceStyleWillChangeEvent:)];
        }
    }
    return self;
}

- (void)handleUserInterfaceStyleWillChangeEvent:(UITraitCollection *)traitCollection {
    if (!_respondsSystemStyleAutomatically) return;
    if (@available(iOS 13.0, *)) {
        if (traitCollection && self.identifierForTrait) {
            self.currentThemeIdentifier = self.identifierForTrait(traitCollection);
        }
    }
}

- (void)setRespondsSystemStyleAutomatically:(BOOL)respondsSystemStyleAutomatically {
    _respondsSystemStyleAutomatically = respondsSystemStyleAutomatically;
    if (@available(iOS 13.0, *)) {
        if (_respondsSystemStyleAutomatically && self.identifierForTrait) {
             self.currentThemeIdentifier = self.identifierForTrait([UITraitCollection currentTraitCollection]);
        }
    }
}

- (void)setCurrentThemeIdentifier:(NSObject<NSCopying> *)currentThemeIdentifier {
    if (![self._themeIdentifiers containsObject:currentThemeIdentifier] && self.themeGenerator) {
        NSObject *theme = self.themeGenerator(currentThemeIdentifier);
        [self addThemeIdentifier:currentThemeIdentifier theme:theme];
    }
    
    QMUIAssert([self._themeIdentifiers containsObject:currentThemeIdentifier], @"QMUIThemeManager", @"%@ should be added to QMUIThemeManager.themes before it becomes current theme identifier.", currentThemeIdentifier);
    
    BOOL themeChanged = _currentThemeIdentifier && ![_currentThemeIdentifier isEqual:currentThemeIdentifier];
    
    _currentThemeIdentifier = currentThemeIdentifier;
    _currentTheme = [self themeForIdentifier:currentThemeIdentifier];
    
    if (themeChanged) {
        [self notifyThemeChanged];
    }
}

- (void)setCurrentTheme:(NSObject *)currentTheme {
    if (![self._themes containsObject:currentTheme] && self.themeIdentifierGenerator) {
        __kindof NSObject<NSCopying> *identifier = self.themeIdentifierGenerator(currentTheme);
        [self addThemeIdentifier:identifier theme:currentTheme];
    }
    
    QMUIAssert([self._themes containsObject:currentTheme], @"QMUIThemeManager", @"%@ should be added to QMUIThemeManager.themes before it becomes current theme.", currentTheme);
    
    BOOL themeChanged = _currentTheme && ![_currentTheme isEqual:currentTheme];
    
    _currentTheme = currentTheme;
    _currentThemeIdentifier = [self identifierForTheme:currentTheme];
    
    if (themeChanged) {
        [self notifyThemeChanged];
    }
}

- (NSArray<NSObject<NSCopying> *> *)themeIdentifiers {
    return self._themeIdentifiers.count ? self._themeIdentifiers.copy : nil;
}

- (NSArray<NSObject *> *)themes {
    return self._themes.count ? self._themes.copy : nil;
}

- (__kindof NSObject *)themeForIdentifier:(__kindof NSObject<NSCopying> *)identifier {
    NSUInteger index = [self._themeIdentifiers indexOfObject:identifier];
    if (index != NSNotFound) return self._themes[index];
    return nil;
}

- (__kindof NSObject<NSCopying> *)identifierForTheme:(__kindof NSObject *)theme {
    NSUInteger index = [self._themes indexOfObject:theme];
    if (index != NSNotFound) return self._themeIdentifiers[index];
    return nil;
}

- (void)addThemeIdentifier:(NSObject<NSCopying> *)identifier theme:(NSObject *)theme {
    QMUIAssert(![self._themeIdentifiers containsObject:identifier], @"QMUIThemeManager", @"unable to add duplicate theme identifier");
    QMUIAssert(![self._themes containsObject:theme], @"QMUIThemeManager", @"unable to add duplicate theme");
    
    [self._themeIdentifiers addObject:identifier];
    [self._themes addObject:theme];
}

- (void)removeThemeIdentifier:(NSObject<NSCopying> *)identifier {
    [self._themeIdentifiers removeObject:identifier];
}

- (void)removeTheme:(NSObject *)theme {
    [self._themes removeObject:theme];
}

- (void)notifyThemeChanged {
    [[NSNotificationCenter defaultCenter] postNotificationName:QMUIThemeDidChangeNotification object:self];
    
    [UIApplication.sharedApplication.windows enumerateObjectsUsingBlock:^(__kindof UIWindow * _Nonnull window, NSUInteger idx, BOOL * _Nonnull stop) {
        if (!window.hidden && window.alpha > 0.01 && window.rootViewController) {
            [window.rootViewController qmui_themeDidChangeByManager:self identifier:self.currentThemeIdentifier theme:self.currentTheme];
            
            // 某些 present style 情况下，window 上可能存在多个 viewController.view，因此需要遍历所有的 subviews，而不只是 window.rootViewController.view
            [window _qmui_themeDidChangeByManager:self identifier:self.currentThemeIdentifier theme:self.currentTheme shouldEnumeratorSubviews:YES];
        }
    }];
}

@end
