timi-utils/src/main/java/com/imyeyu/utils/StringInterpolator.java

package com.imyeyu.utils;

import com.imyeyu.java.TimiJava;
import com.imyeyu.java.bean.CallbackArgReturn;
import com.imyeyu.java.ref.Ref;
import lombok.Getter;
import lombok.Setter;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * 字符串插值器
 *
 * @author 夜雨
 * @version 2022-12-01 00:41
 */
public class StringInterpolator {

	public static final String DOLLAR_OBJ = "\\$\\{(.+?)\\}";
	public static final String SIMPLE_OBJ = "\\{(.+?)\\}";

	/** 缓存解析过的嵌套属性路径 */
	private final Map<String, String[]> deepKeyCache = new ConcurrentHashMap<>();

	/** 正则匹配器 */
	private final Pattern pattern;

	/** 过滤器映射 */
	private final Map<String, CallbackArgReturn<String, String>> filterMap = new HashMap<>();

	/** 空值处理策略 */
	@Setter
	@Getter
	private boolean nullable = false;

	public StringInterpolator(String regex) {
		this.pattern = Pattern.compile(regex);
	}

	/**
	 * 注入变量
	 *
	 * @param template 字符串
	 * @param argsMap  变量表
	 * @return 插值结果
	 */
	public String inject(String template, Map<String, Object> argsMap) {
		if (TimiJava.isEmpty(template) || TimiJava.isEmpty(argsMap)) {
			return template;
		}
		Matcher matcher = pattern.matcher(template);
		StringBuilder result = new StringBuilder();
		while (matcher.find()) {
			String replacement = processReplacement(matcher.group(1), argsMap);
			matcher.appendReplacement(result, Matcher.quoteReplacement(replacement));
		}
		matcher.appendTail(result);
		return result.toString();
	}

	/** 处理单个替换项 */
	private String processReplacement(String expression, Map<String, Object> argsMap) {
		// 解析表达式：变量名和过滤器
		ExpressionParts parts = parseExpression(expression);
		// 获取变量值
		Object value = getVariableValue(parts.variable, argsMap);
		// 应用过滤器
		value = applyFilters(value, parts.filters);
		// 处理空值
		return handleNullValue(value, parts.variable);
	}

	/** 解析表达式为变量名和过滤器数组 */
	private ExpressionParts parseExpression(String expression) {
		if (!expression.contains("|")) {
			return new ExpressionParts(expression.trim(), new String[0]);
		}
		String[] parts = expression.split("\\|");
		String variable = parts[0].trim();
		String[] filters = new String[parts.length - 1];
		for (int i = 1; i < parts.length; i++) {
			filters[i - 1] = parts[i].trim();
		}
		return new ExpressionParts(variable, filters);
	}

	/** 获取变量值，支持嵌套属性 */
	private Object getVariableValue(String variable, Map<String, Object> argsMap) {
		Object value = argsMap.get(variable);
		if (variable.contains(".")) {
			value = getNestedPropertyValue(variable, argsMap);
		}
		return value;
	}

	/** 获取嵌套属性值 */
	private Object getNestedPropertyValue(String deepKey, Map<String, Object> argsMap) {
		String[] keyPath = deepKeyCache.computeIfAbsent(deepKey, k -> k.split("\\."));
		try {
			Object value = argsMap.get(keyPath[0]);
			for (int i = 1; i < keyPath.length && value != null; i++) {
				value = Ref.getFieldValue(value, keyPath[i], Object.class);
			}
			return value;
		} catch (IllegalAccessException e) {
			throw new RuntimeException("ref field error: " + e.getMessage(), e);
		}
	}

	/** 应用过滤器链 */
	private Object applyFilters(Object value, String[] filters) {
		if (TimiJava.isEmpty(filters) || TimiJava.isEmpty(filterMap) || value == null) {
			return value;
		}
		String currentValue = String.valueOf(value);
		for (String filterName : filters) {
			CallbackArgReturn<String, String> filter = filterMap.get(filterName);
			if (filter == null) {
				throw new IllegalArgumentException("not found %s filter for".formatted(filterName));
			}
			currentValue = filter.handler(currentValue);
		}
		return currentValue;
	}

	/** 处理空值情况 */
	private String handleNullValue(Object value, String variable) {
		if (value == null) {
			if (!nullable) {
				throw new NullPointerException("not found %s value".formatted(variable));
			}
			return "";
		}
		return String.valueOf(value);
	}

	public void putFilter(String name, CallbackArgReturn<String, String> callback) {
		filterMap.put(name, callback);
	}

	public void putAllFilter(Map<String, CallbackArgReturn<String, String>> filters) {
		filterMap.putAll(filters);
	}

	public void removeFilter(String name) {
		filterMap.remove(name);
	}

	public void clearFilter() {
		filterMap.clear();
	}

	/** 表达式部分内部类 */
	private record ExpressionParts(String variable, String[] filters) {
	}

	public static StringInterpolator createDollarInterpolator() {
		return new StringInterpolator(DOLLAR_OBJ);
	}

	public static StringInterpolator createSimpleInterpolator() {
		return new StringInterpolator(SIMPLE_OBJ);
	}
}