import React, { useEffect, useState } from 'react';
import { ScrollView, StyleProp, StyleSheet, TextStyle, TouchableOpacity, View, ViewStyle } from 'react-native';
import { ThemedText } from './ThemedText';

export type CascaderItem = {
    name: string;
    [key: string]: any; // 允许其他自定义属性
    children?: CascaderItem[];
};

type CascaderProps = {
    data: CascaderItem[]; // 级联数据
    value?: CascaderItem[]; // 选中的值
    onChange?: (value: CascaderItem[]) => void; // 选中项变化时的回调
    displayRender?: (selectedItems: CascaderItem[]) => React.ReactNode; // 自定义显示内容
    style?: StyleProp<ViewStyle>; // 容器样式
    itemStyle?: StyleProp<ViewStyle>; // 选项样式
    activeItemStyle?: StyleProp<ViewStyle>; // 选中项样式
    textStyle?: StyleProp<TextStyle>; // 文字样式
    activeTextStyle?: StyleProp<TextStyle>; // 选中文字样式
    columnWidth?: number; // 列宽
    showDivider?: boolean; // 是否显示分割线
    dividerColor?: string; // 分割线颜色
    showArrow?: boolean; // 是否显示箭头
};

const CascaderComponent: React.FC<CascaderProps> = ({
    data,
    value = [],
    onChange,
    displayRender,
    style,
    activeItemStyle,
    textStyle,
    activeTextStyle,
    columnWidth = 120,
    showDivider = true,
    dividerColor = '#e0e0e0',
    showArrow = false,
}) => {
    const [selectedItems, setSelectedItems] = useState<CascaderItem[]>(value);
    const [allLevelsData, setAllLevelsData] = useState<CascaderItem[][]>([]);

    // 初始化数据
    useEffect(() => {
        setAllLevelsData([data]);
    }, [data]);

    // 处理选择
    const handleSelect = (item: CascaderItem, level: number) => {
        const newSelectedItems = [...selectedItems.slice(0, level), item];
        setSelectedItems(newSelectedItems);

        // 如果有子项，添加下一级数据
        if (item.children?.length) {
            setAllLevelsData(prev => {
                const newLevels = [...prev.slice(0, level + 1)];
                // 确保 children 存在且是数组
                if (item.children && Array.isArray(item.children)) {
                    newLevels.push(item.children);
                }
                return newLevels;
            });
        } else {
            setAllLevelsData(prev => prev.slice(0, level + 1));
        }

        // 触发onChange回调
        onChange?.(newSelectedItems);
    };

    // 渲染某一级选项
    const renderLevel = (items: CascaderItem[], level: number) => {
        return (
            <View style={[styles.levelContainer]}>
                {items.map((item, index) => {
                    const isActive = selectedItems[level]?.name === item.name;
                    return (
                        <View key={`${level}-${index}`} style={[
                            styles.item,
                            isActive && [styles.activeItem, activeItemStyle]
                        ]}>
                            <ScrollView
                                horizontal
                                showsHorizontalScrollIndicator={false}
                                contentContainerStyle={{ flexGrow: 1 }}
                            >
                                <TouchableOpacity
                                    style={styles.itemContent}
                                    onPress={() => handleSelect(item, level)}
                                >
                                    <ThemedText
                                        style={[
                                            styles.text,
                                            textStyle,
                                            isActive && [styles.activeText, activeTextStyle]
                                        ]}
                                        type='sfPro'
                                    >
                                        {item.name}
                                    </ThemedText>
                                    {showArrow && item.children?.length ? (
                                        <ThemedText style={styles.arrow}>›</ThemedText>
                                    ) : null}
                                </TouchableOpacity>
                            </ScrollView>
                        </View>
                    );
                })}
            </View>
        );
    };

    // 渲染所有级联列
    const renderColumns = () => {
        const totalLevels = allLevelsData.length;
        return allLevelsData.map((items, level) => {
            // 计算每列的宽度
            let width;
            if (totalLevels === 1) {
                width = '100%'; // 只有一级时占满全部宽度
            } else if (totalLevels === 2) {
                width = level === 0 ? '40%' : '60%'; // 两级时第一级40%，第二级60%
            } else {
                // 三级或以上时，前两级各占30%，其余级别平分剩余40%
                if (level < 2) {
                    width = '30%';
                } else {
                    const remainingLevels = totalLevels - 2;
                    width = remainingLevels > 0 ? `${40 / remainingLevels}%` : '40%';
                }
            }

            return (
                <View
                    key={`column-${level}`}
                    style={[
                        styles.column,
                        { width },
                        showDivider && level < totalLevels - 1 && [
                            styles.columnWithDivider,
                            { borderRightColor: dividerColor }
                        ]
                    ]}
                >
                    <ScrollView
                        style={{ flex: 1 }}
                        showsVerticalScrollIndicator={true}
                        contentContainerStyle={{ paddingBottom: 20 }}
                    >
                        {renderLevel(items, level)}
                    </ScrollView>
                </View>
            );
        });
    };

    // 自定义显示内容
    const renderDisplay = () => {
        if (displayRender) {
            return displayRender(selectedItems);
        }
        return selectedItems.map(item => item.name).join(' / ');
    };

    return (
        <View style={[styles.container, style]}>
            <ScrollView
                horizontal
                showsHorizontalScrollIndicator={false}
                contentContainerStyle={styles.scrollContent}
                style={{ flex: 1 }}
            >
                {renderColumns()}
            </ScrollView>
            {displayRender && (
                <View style={styles.displayContainer}>
                    {renderDisplay()}
                </View>
            )}
        </View>
    );
};

const styles = StyleSheet.create({
    container: {
        flex: 1,
        backgroundColor: '#fff',
        height: 300,
    },
    scrollContent: {
        flexGrow: 1,
        height: '100%',
        flexDirection: 'row',
    },
    column: {
        height: '100%',
        maxHeight: '100%',
        flexShrink: 0,
    },
    columnWithDivider: {
        borderRightWidth: 1,
    },
    levelContainer: {
        height: '100%',
        maxHeight: '100%',
    },
    item: {
        flexDirection: 'row',
        justifyContent: 'space-between',
        alignItems: 'center',
        paddingVertical: 12,
        paddingHorizontal: 16,
        minWidth: '100%',
        overflow: 'hidden',
    },
    text: {
        fontSize: 15,
        color: '#333',
        flexShrink: 0, // 禁止收缩
        paddingRight: 4,
    },
    itemContent: {
        flexDirection: 'row',
        alignItems: 'center',
        paddingRight: 16, // 确保有足够的右边距
    },
    activeItem: {
        backgroundColor: '#F6F6F6',
    },
    activeText: {
        color: '#AC7E35',
        fontWeight: '500',
    },
    arrow: {
        fontSize: 18,
        color: '#999',
        marginLeft: 8,
    },
    displayContainer: {
        padding: 12,
        borderTopWidth: 1,
        borderTopColor: '#f0f0f0',
    },
});

export default CascaderComponent;