//
//  KBKeyboardLegacyBuilder.m
//  CustomKeyboard
//

#import "KBKeyboardLegacyBuilder.h"
#import "KBKey.h"
#import "KBKeyButton.h"
#import "KBBackspaceLongPressHandler.h"
#import "KBConfig.h"
#import <Masonry/Masonry.h>

static const CGFloat kKBSpecialKeySquareMultiplier = 1.2;
static const CGFloat kKBReturnWidthMultiplier = 2.4;
static const CGFloat kKBSpaceWidthMultiplier = 3.0;
static inline CGFloat KBLegacyRowHorizontalInset(void) {
    return KBFit(6.0f);
}

@implementation KBKeyboardLegacyBuilder

- (void)buildRow:(UIView *)row
        withKeys:(NSArray<KBKey *> *)keys
edgeSpacerMultiplier:(CGFloat)edgeSpacerMultiplier
         shiftOn:(BOOL)shiftOn
 backspaceHandler:(KBBackspaceLongPressHandler *)backspaceHandler
           target:(id)target
           action:(SEL)action {
    if (!row || keys.count == 0) { return; }

    // 第 4 行（底部控制行）使用单独的布局规则：
    // 123/ABC、Emoji、Send 给定尺寸，Space 自动吃掉剩余宽度。
    BOOL isBottomControlRow = [self kb_isBottomControlRowWithKeys:keys];

    CGFloat spacing = 0;  // 键与键之间的间距
    UIView *previous = nil;
    UIView *leftSpacer = nil;
    UIView *rightSpacer = nil;

    if (edgeSpacerMultiplier > 0.0) {
        leftSpacer = [UIView new];
        rightSpacer = [UIView new];
        leftSpacer.backgroundColor = [UIColor clearColor];
        rightSpacer.backgroundColor = [UIColor clearColor];
        [row addSubview:leftSpacer];
        [row addSubview:rightSpacer];
        [leftSpacer mas_makeConstraints:^(MASConstraintMaker *make) {
            make.left.equalTo(row.mas_left).offset(KBLegacyRowHorizontalInset());
            make.centerY.equalTo(row);
            make.height.mas_equalTo(1);
        }];
        [rightSpacer mas_makeConstraints:^(MASConstraintMaker *make) {
            make.right.equalTo(row.mas_right).offset(-KBLegacyRowHorizontalInset());
            make.centerY.equalTo(row);
            make.height.mas_equalTo(1);
        }];
    }

    for (NSInteger i = 0; i < keys.count; i++) {
        KBKey *key = keys[i];
        KBKeyButton *btn = [[KBKeyButton alloc] init];
        btn.key = key;
        [btn setTitle:key.title forState:UIControlStateNormal];
        // 在设置完标题后，按当前皮肤应用图标与文字显隐
        [btn applyThemeForCurrentKey];
        if (target && action) {
            [btn addTarget:target action:action forControlEvents:UIControlEventTouchDown];
        }
        [row addSubview:btn];

        if (key.type == KBKeyTypeBackspace) {
            [backspaceHandler bindDeleteButton:btn showClearLabel:YES];
        }

        // Shift 按钮选中态随大小写状态变化
        if (key.type == KBKeyTypeShift) {
            btn.selected = shiftOn;
        }

        [btn mas_makeConstraints:^(MASConstraintMaker *make) {
            make.top.bottom.equalTo(row);
            if (previous) {
                make.left.equalTo(previous.mas_right).offset(spacing);
            } else {
                if (leftSpacer) {
                    make.left.equalTo(leftSpacer.mas_right).offset(spacing);
                } else {
                    make.left.equalTo(row.mas_left).offset(KBLegacyRowHorizontalInset());
                }
            }
        }];

        // 字符键：等宽
        if (key.type == KBKeyTypeCharacter) {
            if (previous && [previous isKindOfClass:[KBKeyButton class]]) {
                KBKeyButton *prevBtn = (KBKeyButton *)previous;
                if (prevBtn.key.type == KBKeyTypeCharacter) {
                    [btn mas_makeConstraints:^(MASConstraintMaker *make) {
                        make.width.equalTo(previous);
                    }];
                }
            }
        } else {
            // special keys: 宽度在第二遍统一设置
        }

        previous = btn;
    }

    // 右侧使用内边距或右占位
    if (previous) {
        [previous mas_makeConstraints:^(MASConstraintMaker *make) {
            if (rightSpacer) {
                make.right.equalTo(rightSpacer.mas_left).offset(-spacing);
            } else {
                make.right.equalTo(row.mas_right).offset(-KBLegacyRowHorizontalInset());
            }
        }];
    }

    // 底部控制行：在第一轮已完成左右约束的前提下，仅给 123/ABC、Emoji、Send 指定宽度，
    // Space 不加宽度约束，让其自动填充剩余空间。
    if (isBottomControlRow) {
        [self kb_applyBottomControlRowWidthInRow:row];
        return;
    }

    // 第二遍：以首个字符键为基准，统一设置特殊键宽度倍数
    KBKeyButton *firstChar = nil;
    BOOL hasCharacterInRow = NO;
    for (UIView *v in row.subviews) {
        if (![v isKindOfClass:[KBKeyButton class]]) continue;
        KBKeyButton *b = (KBKeyButton *)v;
        if (b.key.type == KBKeyTypeCharacter) {
            firstChar = b;
            hasCharacterInRow = YES;
            break;
        }
    }
    // 若该行没有字符键（例如底部控制行之外的特殊行），则使用行内第一个按钮作为基准宽度
    if (!firstChar) {
        for (UIView *v in row.subviews) {
            if ([v isKindOfClass:[KBKeyButton class]]) {
                firstChar = (KBKeyButton *)v;
                break;
            }
        }
    }
    if (firstChar) {
        // 如果该行本身没有字符键（如底部控制行），且基准按钮是 123/ABC/#+= 等，
        // 也将其约束为 1:1，避免 123/ABC 不是正方形。
        if (!hasCharacterInRow &&
            (firstChar.key.type == KBKeyTypeModeChange ||
             firstChar.key.type == KBKeyTypeSymbolsToggle ||
             firstChar.key.type == KBKeyTypeCustom)) {
            [firstChar mas_makeConstraints:^(MASConstraintMaker *make) {
                make.width.equalTo(firstChar.mas_height).multipliedBy(kKBSpecialKeySquareMultiplier);
            }];
        }

        for (UIView *v in row.subviews) {
            if (![v isKindOfClass:[KBKeyButton class]]) continue;
            KBKeyButton *b = (KBKeyButton *)v;

            // 避免对基准按钮自身添加 self == self * k 的无效约束
            if (b == firstChar) continue;
            if (b.key.type == KBKeyTypeCharacter) continue;

            BOOL isBottomModeKey = (b.key.type == KBKeyTypeModeChange) ||
                                   (b.key.type == KBKeyTypeSymbolsToggle) ||
                                   (b.key.type == KBKeyTypeCustom);
            // 一类键强制近似正方形（宽 ~ 高）
            if (b.key.type == KBKeyTypeShift ||
                b.key.type == KBKeyTypeBackspace ||
                isBottomModeKey) {
                [b mas_makeConstraints:^(MASConstraintMaker *make) {
                    make.width.equalTo(b.mas_height).multipliedBy(kKBSpecialKeySquareMultiplier);
                }];
                continue;
            }

            CGFloat multiplier = 1.5;

            // Space：宽度更大
            if (b.key.type == KBKeyTypeSpace) {
                multiplier = kKBSpaceWidthMultiplier;
            }
            // Send 按钮：宽度为基准键的 2.4 倍
            else if (b.key.type == KBKeyTypeReturn) {
                multiplier = kKBReturnWidthMultiplier;
            }
            // 其它特殊键（如 Globe）保持适度放大
            else if (b.key.type == KBKeyTypeGlobe) {
                multiplier = 1.5;
            }

            [b mas_makeConstraints:^(MASConstraintMaker *make) {
                make.width.equalTo(firstChar).multipliedBy(multiplier);
            }];
        }

        // 如果有左右占位，则把占位宽度设置为字符键宽度的一定倍数，以实现整体居中；
        // 同时强约束左右占位宽度相等，避免在某些系统上由于布局冲突导致只压缩一侧，
        // 出现“左侧有空隙，右侧无空隙”的情况。
        if (leftSpacer && rightSpacer) {
            // 1) 左右占位宽度必须相等
            [leftSpacer mas_makeConstraints:^(MASConstraintMaker *make) {
                make.width.equalTo(rightSpacer);
            }];
            // 2) 同时都接近字符键宽度的 edgeSpacerMultiplier 倍数
            [rightSpacer mas_makeConstraints:^(MASConstraintMaker *make) {
                make.width.equalTo(firstChar).multipliedBy(edgeSpacerMultiplier);
            }];
        }
    }
}

#pragma mark - Row Helpers (Bottom Control Row)

// 判断是否为底部控制行：包含 Space + Return，且有 ModeChange/SymbolsToggle，
// 并且不再含字符键。
- (BOOL)kb_isBottomControlRowWithKeys:(NSArray<KBKey *> *)keys {
    BOOL hasSpace = NO;
    BOOL hasReturn = NO;
    BOOL hasModeOrSymbols = NO;
    BOOL hasCharacters = NO;

    for (KBKey *k in keys) {
        if (k.type == KBKeyTypeSpace) {
            hasSpace = YES;
        } else if (k.type == KBKeyTypeReturn) {
            hasReturn = YES;
        } else if (k.type == KBKeyTypeModeChange || k.type == KBKeyTypeSymbolsToggle) {
            hasModeOrSymbols = YES;
        } else if (k.type == KBKeyTypeCharacter) {
            hasCharacters = YES;
        }
    }
    return (hasSpace && hasReturn && hasModeOrSymbols && !hasCharacters);
}

- (void)kb_applyBottomControlRowWidthInRow:(UIView *)row {
    if (!row) { return; }

    KBKeyButton *modeBtn = nil;
    KBKeyButton *spaceBtn = nil;
    KBKeyButton *retBtn = nil;
    NSMutableArray<KBKeyButton *> *customButtons = [NSMutableArray array];

    for (UIView *v in row.subviews) {
        if (![v isKindOfClass:[KBKeyButton class]]) continue;
        KBKeyButton *b = (KBKeyButton *)v;
        switch (b.key.type) {
            case KBKeyTypeModeChange:
            case KBKeyTypeSymbolsToggle:
                modeBtn = b;
                break;
            case KBKeyTypeCustom:
                [customButtons addObject:b];
                break;
            case KBKeyTypeSpace:
                spaceBtn = b;
                break;
            case KBKeyTypeReturn:
                retBtn = b;
                break;
            default:
                break;
        }
    }

    if (!modeBtn || customButtons.count == 0 || !spaceBtn || !retBtn) {
        return;
    }

    [modeBtn mas_makeConstraints:^(MASConstraintMaker *make) {
        make.width.equalTo(row.mas_height).multipliedBy(kKBSpecialKeySquareMultiplier);
    }];
    for (KBKeyButton *custom in customButtons) {
        [custom mas_makeConstraints:^(MASConstraintMaker *make) {
            make.width.equalTo(row.mas_height).multipliedBy(kKBSpecialKeySquareMultiplier);
        }];
    }
    [retBtn mas_makeConstraints:^(MASConstraintMaker *make) {
        make.width.equalTo(modeBtn.mas_width).multipliedBy(2.0);
    }];
    // Space 不设置宽度；通过此前已建立的左右约束自动占满剩余宽度。
    (void)spaceBtn;
}

@end