//
//  KBKeyboardLayoutEngine.m
//  CustomKeyboard
//

#import "KBKeyboardLayoutEngine.h"
#import "KBKeyboardLayoutConfig.h"
#import "KBKeyboardKeyFactory.h"
#import "KBKey.h"
#import "KBConfig.h"

@interface KBKeyboardLayoutEngine ()
@property (nonatomic, strong) KBKeyboardLayoutConfig *layoutConfig;
@end

@implementation KBKeyboardLayoutEngine

- (instancetype)initWithLayoutConfig:(KBKeyboardLayoutConfig *)layoutConfig {
    self = [super init];
    if (self) {
        _layoutConfig = layoutConfig;
    }
    return self;
}

- (CGFloat)rowSpacingForLayout:(KBKeyboardLayout *)layout {
    KBKeyboardLayoutConfig *config = self.layoutConfig;
    NSNumber *layoutSpacing = layout.rowSpacing;
    return [self kb_metricValue:layoutSpacing fallback:config.metrics.rowSpacing defaultValue:8.0];
}

- (CGFloat)topInsetForLayout:(KBKeyboardLayout *)layout {
    KBKeyboardLayoutConfig *config = self.layoutConfig;
    NSNumber *layoutInset = layout.topInset;
    return [self kb_metricValue:layoutInset fallback:config.metrics.topInset defaultValue:8.0];
}

- (CGFloat)bottomInsetForLayout:(KBKeyboardLayout *)layout {
    KBKeyboardLayoutConfig *config = self.layoutConfig;
    NSNumber *layoutInset = layout.bottomInset;
    return [self kb_metricValue:layoutInset fallback:config.metrics.bottomInset defaultValue:6.0];
}

- (CGFloat)rowHeightForRow:(KBKeyboardRowConfig *)row {
    KBKeyboardLayoutConfig *config = self.layoutConfig;
    NSNumber *height = row.height ?: config.metrics.keyHeight;
    CGFloat value = [self kb_numberValue:height defaultValue:40.0];
    return [self kb_scaledValue:value];
}

- (CGFloat)gapForRow:(KBKeyboardRowConfig *)row {
    KBKeyboardLayoutConfig *config = self.layoutConfig;
    return [self kb_metricValue:row.gap fallback:config.metrics.gap defaultValue:5.0];
}

- (CGFloat)insetLeftForRow:(KBKeyboardRowConfig *)row {
    KBKeyboardLayoutConfig *config = self.layoutConfig;
    return [self kb_metricValue:row.insetLeft fallback:config.metrics.edgeInset defaultValue:0.0];
}

- (CGFloat)insetRightForRow:(KBKeyboardRowConfig *)row {
    KBKeyboardLayoutConfig *config = self.layoutConfig;
    return [self kb_metricValue:row.insetRight fallback:config.metrics.edgeInset defaultValue:0.0];
}

- (CGFloat)widthForItem:(KBKeyboardRowItem *)item key:(KBKey *)key {
    CGFloat width = 0.0;
    if (item.widthValue.doubleValue > 0.0) {
        width = item.widthValue.doubleValue;
    } else if (item.width.length > 0) {
        if ([item.width.lowercaseString isEqualToString:@"flex"]) {
            return 0.0;
        }
        width = [self kb_metricWidthForKey:item.width];
        if (width <= 0.0) {
            width = item.width.doubleValue;
        }
    }

    if (width <= 0.0) {
        KBKeyboardLayoutMetrics *m = self.layoutConfig.metrics;
        if ([item.itemId hasPrefix:@"letter:"] ||
            [item.itemId hasPrefix:@"digit:"] ||
            [item.itemId hasPrefix:@"sym:"]) {
            width = m.letterWidth.doubleValue;
        } else if (key.type == KBKeyTypeReturn) {
            width = m.sendWidth.doubleValue;
        } else if (key.type == KBKeyTypeSpace) {
            return 0.0;
        } else {
            width = m.controlWidth.doubleValue;
        }
    }

    if (width <= 0.0) {
        if ([item.itemId hasPrefix:@"letter:"] ||
            [item.itemId hasPrefix:@"digit:"] ||
            [item.itemId hasPrefix:@"sym:"]) {
            width = 32.0;
        } else if (key.type == KBKeyTypeReturn) {
            width = 88.0;
        } else if (key.type == KBKeyTypeSpace) {
            return 0.0;
        } else {
            width = 41.0;
        }
    }

    return width > 0.0 ? [self kb_scaledValue:width] : 0.0;
}

- (CGFloat)fontSizeForItem:(KBKeyboardRowItem *)item key:(KBKey *)key {
    NSString *fontKey = nil;
    if ([item.itemId hasPrefix:@"letter:"]) {
        fontKey = @"letter";
    } else if ([item.itemId hasPrefix:@"digit:"]) {
        fontKey = @"digit";
    } else if ([item.itemId hasPrefix:@"sym:"]) {
        fontKey = @"symbol";
    } else {
        KBKeyboardKeyDef *def = [self.layoutConfig keyDefForIdentifier:item.itemId];
        fontKey = def.font;
    }

    if (fontKey.length == 0) {
        switch (key.type) {
            case KBKeyTypeModeChange:
            case KBKeyTypeSymbolsToggle:
                fontKey = @"mode";
                break;
            case KBKeyTypeSpace:
                fontKey = @"space";
                break;
            case KBKeyTypeReturn:
                fontKey = @"send";
                break;
            default:
                fontKey = @"symbol";
                break;
        }
    }

    return [self fontSizeForFontKey:fontKey];
}

- (CGFloat)fontSizeForFontKey:(NSString *)fontKey {
    KBKeyboardLayoutFonts *fonts = self.layoutConfig.fonts;
    CGFloat size = 0.0;
    if ([fontKey isEqualToString:@"letter"]) { size = fonts.letter.doubleValue; }
    else if ([fontKey isEqualToString:@"digit"]) { size = fonts.digit.doubleValue; }
    else if ([fontKey isEqualToString:@"symbol"]) { size = fonts.symbol.doubleValue; }
    else if ([fontKey isEqualToString:@"mode"]) { size = fonts.mode.doubleValue; }
    else if ([fontKey isEqualToString:@"space"]) { size = fonts.space.doubleValue; }
    else if ([fontKey isEqualToString:@"send"]) { size = fonts.send.doubleValue; }
    if (size <= 0.0) { size = 18.0; }
    return [self kb_scaledValue:size];
}

/// 计算跨行统一字符键宽度：遍历每行各自的 insets/gap/非字符键宽度，
/// 取各行可用字符键宽度的最小值，确保所有行都能容纳。
/// 当各行有效宽度相同时返回 0（无需统一）。
- (CGFloat)calculateUniformCharKeyWidthForRows:(NSArray<KBKeyboardRowConfig *> *)rows
                                    keyFactory:(KBKeyboardKeyFactory *)keyFactory
                                       shiftOn:(BOOL)shiftOn {
    CGFloat minWidth = CGFLOAT_MAX;
    CGFloat maxWidth = 0.0;
    BOOL hasCharRow = NO;
    CGFloat containerWidth = KBScreenWidth();

    for (KBKeyboardRowConfig *row in rows) {
        if (row.segments) { continue; } // 跳过分段行
        NSArray<KBKeyboardRowItem *> *items = [row resolvedItems];
        NSUInteger charCount = 0;
        CGFloat nonCharWidth = 0.0;
        for (KBKeyboardRowItem *item in items) {
            BOOL isChar = [item.itemId hasPrefix:@"letter:"] ||
                          [item.itemId hasPrefix:@"digit:"] ||
                          [item.itemId hasPrefix:@"sym:"];
            if (isChar) {
                charCount++;
            } else {
                KBKey *key = [keyFactory keyForItemId:item.itemId shiftOn:shiftOn];
                CGFloat w = [self widthForItem:item key:key];
                nonCharWidth += w;
            }
        }
        if (charCount == 0) { continue; } // 跳过无字符键的行（如底部控制行）
        hasCharRow = YES;

        // 使用每行各自配置的 insets 和 gap
        CGFloat gap = [self gapForRow:row];
        CGFloat insetLeft = [self insetLeftForRow:row];
        CGFloat insetRight = [self insetRightForRow:row];
        CGFloat totalGaps = (items.count > 1) ? (items.count - 1) * gap : 0.0;
        CGFloat available = containerWidth - insetLeft - insetRight - totalGaps - nonCharWidth;
        CGFloat width = available / charCount;

        if (width < minWidth) { minWidth = width; }
        if (width > maxWidth) { maxWidth = width; }
    }

    if (!hasCharRow || minWidth <= 0.0 || minWidth >= CGFLOAT_MAX) { return 0.0; }
    // 各行有效宽度相同时无需统一
    if (fabs(maxWidth - minWidth) < 0.5) { return 0.0; }
    return minWidth;
}

#pragma mark - Helpers

- (CGFloat)kb_scaledValue:(CGFloat)designValue {
    if (self.layoutConfig) {
        return [self.layoutConfig scaledValue:designValue];
    }
    return KBFit(designValue);
}

- (CGFloat)kb_numberValue:(NSNumber *)value defaultValue:(CGFloat)defaultValue {
    if ([value isKindOfClass:[NSNumber class]]) {
        return value.doubleValue;
    }
    return defaultValue;
}

- (CGFloat)kb_metricValue:(NSNumber *)value fallback:(NSNumber *)fallback defaultValue:(CGFloat)defaultValue {
    CGFloat v = [self kb_numberValue:value defaultValue:-1.0];
    if (v < 0.0) {
        v = [self kb_numberValue:fallback defaultValue:defaultValue];
    }
    if (v < 0.0) {
        v = defaultValue;
    }
    return [self kb_scaledValue:v];
}

- (CGFloat)kb_metricWidthForKey:(NSString *)key {
    KBKeyboardLayoutMetrics *m = self.layoutConfig.metrics;
    if ([key isEqualToString:@"letterWidth"]) { return m.letterWidth.doubleValue; }
    if ([key isEqualToString:@"controlWidth"]) { return m.controlWidth.doubleValue; }
    if ([key isEqualToString:@"sendWidth"]) { return m.sendWidth.doubleValue; }
    if ([key isEqualToString:@"symbolsWideWidth"]) { return m.symbolsWideWidth.doubleValue; }
    if ([key isEqualToString:@"symbolsSideWidth"]) { return m.symbolsSideWidth.doubleValue; }
    return 0.0;
}

@end