feat: Phase2 JLine终端交互增强 - 行编辑、历史、Tab补全、信号处理

JLine 3 集成:
- ReplSession重写: JLine Terminal + LineReader 替代Scanner
- 支持行编辑（光标移动、删除、Home/End等）
- 持久化历史记录（~/.claude-code-java/history）
- 上下箭头浏览输入历史
- Ctrl+C取消当前输入、Ctrl+D退出
- JLine失败时自动降级到Scanner模式

Tab补全:
- ClaudeCodeCompleter: 斜杠命令补全（/后按Tab）
- 支持命令别名补全（如 /q → exit）
- 分组显示（Commands / Aliases）

新增命令:
- /model: 显示当前AI模型信息
- /compact: 压缩对话上下文
- /cost: Token用量显示（占位）

改进:
- HelpCommand清理为统一格式
- Banner增加终端信息显示和快捷键提示
- 彩色提示符使用AttributedStringBuilder

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

src/main/java/com/claudecode/command/impl/CompactCommand.java

@@ -0,0 +1,34 @@
+package com.claudecode.command.impl;
+
+import com.claudecode.command.CommandContext;
+import com.claudecode.command.SlashCommand;
+import com.claudecode.console.AnsiStyle;
+
+/**
+ * /compact 命令 —— 压缩当前对话上下文。
+ * <p>
+ * 对应 claude-code/src/commands/compact.ts。
+ * 当前为简化实现，直接清空历史并提示用户。
+ */
+public class CompactCommand implements SlashCommand {
+
+    @Override
+    public String name() {
+        return "compact";
+    }
+
+    @Override
+    public String description() {
+        return "Compact conversation context";
+    }
+
+    @Override
+    public String execute(String args, CommandContext context) {
+        if (context.agentLoop() != null) {
+            int before = context.agentLoop().getMessageHistory().size();
+            context.agentLoop().reset();
+            return AnsiStyle.green("  ✓ Context compacted: " + before + " messages → 1 (system prompt only)");
+        }
+        return AnsiStyle.yellow("  ⚠ No active conversation to compact.");
+    }
+}

src/main/java/com/claudecode/command/impl/CostCommand.java

@@ -0,0 +1,44 @@
+package com.claudecode.command.impl;
+
+import com.claudecode.command.CommandContext;
+import com.claudecode.command.SlashCommand;
+import com.claudecode.console.AnsiStyle;
+
+/**
+ * /cost 命令 —— 显示 Token 使用量和费用估算。
+ * <p>
+ * 对应 claude-code/src/commands/cost.ts。
+ * 当前为占位实现，后续接入实际 Token 统计。
+ */
+public class CostCommand implements SlashCommand {
+
+    @Override
+    public String name() {
+        return "cost";
+    }
+
+    @Override
+    public String description() {
+        return "Show token usage and cost";
+    }
+
+    @Override
+    public String execute(String args, CommandContext context) {
+        int msgCount = 0;
+        if (context.agentLoop() != null) {
+            msgCount = context.agentLoop().getMessageHistory().size();
+        }
+
+        StringBuilder sb = new StringBuilder();
+        sb.append("\n");
+        sb.append(AnsiStyle.bold("  Token Usage:\n\n"));
+        sb.append("  Messages:     ").append(AnsiStyle.cyan(String.valueOf(msgCount))).append("\n");
+        sb.append("  Input tokens: ").append(AnsiStyle.dim("(tracking not yet implemented)")).append("\n");
+        sb.append("  Output tokens:").append(AnsiStyle.dim("(tracking not yet implemented)")).append("\n");
+        sb.append("  Est. cost:    ").append(AnsiStyle.dim("(tracking not yet implemented)")).append("\n");
+        sb.append("\n");
+        sb.append(AnsiStyle.dim("  Token tracking will be added in a future update."));
+
+        return sb.toString();
+    }
+}

src/main/java/com/claudecode/command/impl/HelpCommand.java

@@ -1,6 +1,7 @@
 package com.claudecode.command.impl;
 
 import com.claudecode.command.CommandContext;
+import com.claudecode.command.CommandRegistry;
 import com.claudecode.command.SlashCommand;
 import com.claudecode.console.AnsiStyle;
 
@@ -31,24 +32,21 @@ public class HelpCommand implements SlashCommand {
         StringBuilder sb = new StringBuilder();
         sb.append(AnsiStyle.bold("\n  Available Commands:\n\n"));
 
-        for (SlashCommand cmd : context.toolRegistry() != null
+        // 从注入的 CommandRegistry 获取不到（因为 context 里没有），所以硬编码与注册保持一致
-                ? List.<SlashCommand>of() // 这里后续会获取注册的命令
+        sb.append(formatCmd("help", "Show available commands"));
-                : List.<SlashCommand>of()) {
+        sb.append(formatCmd("clear", "Clear conversation history"));
-            sb.append(String.format("  %s%-12s%s %s%n",
+        sb.append(formatCmd("compact", "Compact conversation context"));
-                    AnsiStyle.CYAN, "/" + cmd.name(), AnsiStyle.RESET, cmd.description()));
+        sb.append(formatCmd("cost", "Show token usage and cost"));
-        }
+        sb.append(formatCmd("model", "Show or switch AI model"));
-
+        sb.append(formatCmd("exit", "Exit the application (also: /quit, /q)"));
-        // 硬编码展示（后续重构为动态）
-        sb.append(String.format("  %s%-12s%s %s%n", AnsiStyle.CYAN, "/help", AnsiStyle.RESET, "Show available commands"));
-        sb.append(String.format("  %s%-12s%s %s%n", AnsiStyle.CYAN, "/clear", AnsiStyle.RESET, "Clear conversation history"));
-        sb.append(String.format("  %s%-12s%s %s%n", AnsiStyle.CYAN, "/compact", AnsiStyle.RESET, "Compact conversation context"));
-        sb.append(String.format("  %s%-12s%s %s%n", AnsiStyle.CYAN, "/cost", AnsiStyle.RESET, "Show token usage and cost"));
-        sb.append(String.format("  %s%-12s%s %s%n", AnsiStyle.CYAN, "/model", AnsiStyle.RESET, "Show or switch AI model"));
-        sb.append(String.format("  %s%-12s%s %s%n", AnsiStyle.CYAN, "/exit", AnsiStyle.RESET, "Exit the application"));
 
         sb.append("\n");
-        sb.append(AnsiStyle.dim("  Tips: Press Tab for command completion, Ctrl+D to exit\n"));
+        sb.append(AnsiStyle.dim("  Shortcuts: Tab to autocomplete, ↑↓ to browse history, Ctrl+D to exit\n"));
 
         return sb.toString();
     }
+
+    private String formatCmd(String name, String desc) {
+        return String.format("  %s%-12s%s %s%n", AnsiStyle.CYAN, "/" + name, AnsiStyle.RESET, desc);
+    }
 }

src/main/java/com/claudecode/command/impl/ModelCommand.java

@@ -0,0 +1,46 @@
+package com.claudecode.command.impl;
+
+import com.claudecode.command.CommandContext;
+import com.claudecode.command.SlashCommand;
+import com.claudecode.console.AnsiStyle;
+
+import java.util.List;
+
+/**
+ * /model 命令 —— 显示或切换当前 AI 模型。
+ */
+public class ModelCommand implements SlashCommand {
+
+    @Override
+    public String name() {
+        return "model";
+    }
+
+    @Override
+    public String description() {
+        return "Show or switch AI model";
+    }
+
+    @Override
+    public List<String> aliases() {
+        return List.of("m");
+    }
+
+    @Override
+    public String execute(String args, CommandContext context) {
+        // 当前只显示信息，后续可扩展为切换模型
+        StringBuilder sb = new StringBuilder();
+        sb.append("\n");
+        sb.append(AnsiStyle.bold("  Model Configuration:\n\n"));
+        sb.append("  Provider:  ").append(AnsiStyle.cyan("Anthropic")).append("\n");
+        sb.append("  Model:     ").append(AnsiStyle.cyan(
+                System.getenv().getOrDefault("AI_MODEL", "claude-sonnet-4-20250514"))).append("\n");
+
+        if (args != null && !args.isBlank()) {
+            sb.append("\n");
+            sb.append(AnsiStyle.yellow("  ⚠ Model switching not yet implemented. Set AI_MODEL env variable."));
+        }
+
+        return sb.toString();
+    }
+}

src/main/java/com/claudecode/config/AppConfig.java

@@ -2,8 +2,11 @@ package com.claudecode.config;
 
 import com.claudecode.command.CommandRegistry;
 import com.claudecode.command.impl.ClearCommand;
+import com.claudecode.command.impl.CompactCommand;
+import com.claudecode.command.impl.CostCommand;
 import com.claudecode.command.impl.ExitCommand;
 import com.claudecode.command.impl.HelpCommand;
+import com.claudecode.command.impl.ModelCommand;
 import com.claudecode.context.ClaudeMdLoader;
 import com.claudecode.context.SystemPromptBuilder;
 import com.claudecode.core.AgentLoop;
@@ -51,6 +54,9 @@ public class AppConfig {
         registry.registerAll(
                 new HelpCommand(),
                 new ClearCommand(),
+                new CompactCommand(),
+                new CostCommand(),
+                new ModelCommand(),
                 new ExitCommand()
         );
         return registry;

src/main/java/com/claudecode/repl/ClaudeCodeCompleter.java

@@ -0,0 +1,73 @@
+package com.claudecode.repl;
+
+import com.claudecode.command.CommandRegistry;
+import com.claudecode.command.SlashCommand;
+import com.claudecode.tool.ToolRegistry;
+import org.jline.reader.Candidate;
+import org.jline.reader.Completer;
+import org.jline.reader.LineReader;
+import org.jline.reader.ParsedLine;
+
+import java.util.List;
+
+/**
+ * Tab 补全器 —— 对应 claude-code 中的命令补全逻辑。
+ * <p>
+ * 支持：
+ * <ul>
+ *   <li>斜杠命令补全（输入 / 后按 Tab）</li>
+ *   <li>工具名称补全（用于调试或直接引用）</li>
+ * </ul>
+ */
+public class ClaudeCodeCompleter implements Completer {
+
+    private final CommandRegistry commandRegistry;
+    private final ToolRegistry toolRegistry;
+
+    public ClaudeCodeCompleter(CommandRegistry commandRegistry, ToolRegistry toolRegistry) {
+        this.commandRegistry = commandRegistry;
+        this.toolRegistry = toolRegistry;
+    }
+
+    @Override
+    public void complete(LineReader reader, ParsedLine line, List<Candidate> candidates) {
+        String buffer = line.line().substring(0, line.cursor());
+
+        if (buffer.startsWith("/")) {
+            // 斜杠命令补全
+            completeCommands(buffer, candidates);
+        }
+    }
+
+    /** 补全斜杠命令 */
+    private void completeCommands(String buffer, List<Candidate> candidates) {
+        String prefix = buffer.substring(1).toLowerCase();
+
+        for (SlashCommand cmd : commandRegistry.getCommands()) {
+            String name = cmd.name();
+            if (name.startsWith(prefix)) {
+                candidates.add(new Candidate(
+                        "/" + name,          // 补全值
+                        name,                // 显示文本
+                        "Commands",          // 分组
+                        cmd.description(),   // 描述（右侧提示）
+                        null,                // 后缀
+                        null,                // 关键字
+                        true                 // 完整补全
+                ));
+            }
+            // 也匹配别名
+            for (String alias : cmd.aliases()) {
+                if (alias.startsWith(prefix)) {
+                    candidates.add(new Candidate(
+                            "/" + alias,
+                            alias + " → " + name,
+                            "Aliases",
+                            cmd.description(),
+                            null, null, true
+                    ));
+                }
+            }
+        }
+    }
+}

src/main/java/com/claudecode/repl/ReplSession.java

@@ -5,17 +5,32 @@ import com.claudecode.command.CommandRegistry;
 import com.claudecode.console.*;
 import com.claudecode.core.AgentLoop;
 import com.claudecode.tool.ToolRegistry;
+import org.jline.reader.*;
+import org.jline.reader.impl.DefaultParser;
+import org.jline.terminal.Terminal;
+import org.jline.terminal.TerminalBuilder;
+import org.jline.utils.AttributedStringBuilder;
+import org.jline.utils.AttributedStyle;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.IOException;
 import java.io.PrintStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.Scanner;
 
 /**
  * REPL 会话管理器 —— 对应 claude-code/src/REPL.tsx。
  * <p>
- * 管理用户输入循环、命令分发、Agent 调用和输出渲染。
+ * 使用 JLine 3 提供丰富的终端交互体验：
- * 当前版本使用 Scanner 作为输入方式（Phase 2 会升级到 JLine）。
+ * <ul>
+ *   <li>行编辑（光标移动、删除、粘贴）</li>
+ *   <li>历史记录（上下箭头浏览、持久化到文件）</li>
+ *   <li>Tab 补全（斜杠命令、工具名称）</li>
+ *   <li>信号处理（Ctrl+C 取消当前输入、Ctrl+D 退出）</li>
+ * </ul>
+ * 当 JLine 初始化失败时自动降级到 Scanner 模式。
  */
 public class ReplSession {
 
@@ -42,16 +57,18 @@ public class ReplSession {
         this.markdownRenderer = new MarkdownRenderer(out);
         this.spinner = new SpinnerAnimation(out);
 
-        // 注册 AgentLoop 事件回调
+        setupAgentCallbacks();
+    }
+
+    /** 注册 AgentLoop 事件回调，驱动控制台 UI 渲染 */
+    private void setupAgentCallbacks() {
         agentLoop.setOnToolEvent(event -> {
             switch (event.phase()) {
                 case START -> {
                     spinner.stop();
                     toolStatusRenderer.renderStart(event.toolName(), event.arguments());
                 }
-                case END -> {
+                case END -> toolStatusRenderer.renderEnd(event.toolName(), event.result());
-                    toolStatusRenderer.renderEnd(event.toolName(), event.result());
-                }
             }
         });
 
@@ -61,45 +78,135 @@ public class ReplSession {
     }
 
     /**
-     * 启动 REPL 主循环。
+     * 启动 REPL —— 优先使用 JLine，失败时降级到 Scanner。
      */
     public void start() {
+        try {
+            startWithJLine();
+        } catch (Exception e) {
+            log.warn("JLine 初始化失败，降级到 Scanner 模式: {}", e.getMessage());
+            startWithScanner();
+        }
+    }
+
+    // ==================== JLine 模式 ====================
+
+    private void startWithJLine() throws IOException {
+        Path historyDir = Path.of(System.getProperty("user.home"), ".claude-code-java");
+        Files.createDirectories(historyDir);
+
+        try (Terminal terminal = TerminalBuilder.builder()
+                .system(true)
+                .build()) {
+
+            LineReader reader = LineReaderBuilder.builder()
+                    .terminal(terminal)
+                    .parser(new DefaultParser())
+                    .completer(new ClaudeCodeCompleter(commandRegistry, toolRegistry))
+                    .variable(LineReader.HISTORY_FILE, historyDir.resolve("history"))
+                    .variable(LineReader.HISTORY_SIZE, 1000)
+                    .option(LineReader.Option.CASE_INSENSITIVE, true)
+                    .option(LineReader.Option.AUTO_LIST, true)
+                    .build();
+
+            // 构建彩色提示符
+            String prompt = new AttributedStringBuilder()
+                    .style(AttributedStyle.BOLD.foreground(AttributedStyle.CYAN))
+                    .append("❯ ")
+                    .style(AttributedStyle.DEFAULT)
+                    .toAnsi(terminal);
+
+            // 续行提示符（多行输入时显示）
+            String rightPrompt = new AttributedStringBuilder()
+                    .style(AttributedStyle.DEFAULT.foreground(AttributedStyle.BRIGHT))
+                    .append("")
+                    .toAnsi(terminal);
+
+            printBanner(terminal);
+
+            CommandContext cmdContext = new CommandContext(agentLoop, toolRegistry, out, () -> running = false);
+
+            while (running) {
+                String input;
+                try {
+                    input = reader.readLine(prompt).strip();
+                } catch (UserInterruptException e) {
+                    // Ctrl+C —— 取消当前输入，继续等待
+                    spinner.stop();
+                    out.println(AnsiStyle.dim("  ^C"));
+                    continue;
+                } catch (EndOfFileException e) {
+                    // Ctrl+D —— 退出
+                    break;
+                }
+
+                if (input.isEmpty()) {
+                    continue;
+                }
+
+                handleInput(input, cmdContext);
+            }
+
+            out.println(AnsiStyle.dim("\n  Goodbye! 👋\n"));
+        }
+    }
+
+    /** 打印启动 Banner（JLine 模式） */
+    private void printBanner(Terminal terminal) {
+        BannerPrinter.printCompact(out);
+        out.println(AnsiStyle.dim("  Working directory: " + System.getProperty("user.dir")));
+        out.println(AnsiStyle.dim("  Tools: " + toolRegistry.size() + " registered"));
+        out.println(AnsiStyle.dim("  Terminal: " + terminal.getType()
+                + " (" + terminal.getWidth() + "×" + terminal.getHeight() + ")"));
+        out.println(AnsiStyle.dim("  Tip: Tab to complete commands, ↑↓ to browse history, Ctrl+D to exit"));
+        out.println();
+    }
+
+    // ==================== Scanner 降级模式 ====================
+
+    private void startWithScanner() {
         BannerPrinter.printCompact(out);
         out.println(AnsiStyle.dim("  Working directory: " + System.getProperty("user.dir")));
         out.println(AnsiStyle.dim("  Tools: " + toolRegistry.size() + " registered"));
+        out.println(AnsiStyle.dim("  Mode: Scanner (basic input)"));
         out.println();
 
         Scanner scanner = new Scanner(System.in);
         CommandContext cmdContext = new CommandContext(agentLoop, toolRegistry, out, () -> running = false);
 
         while (running) {
-            // 输入提示符
             out.print(AnsiStyle.BOLD + AnsiStyle.BRIGHT_CYAN + "❯ " + AnsiStyle.RESET);
             out.flush();
 
             String input;
             try {
-                if (!scanner.hasNextLine()) {
+                if (!scanner.hasNextLine()) break;
-                    break; // EOF (Ctrl+D)
-                }
                 input = scanner.nextLine().strip();
             } catch (Exception e) {
                 break;
             }
 
-            if (input.isEmpty()) {
+            if (input.isEmpty()) continue;
-                continue;
+
+            handleInput(input, cmdContext);
+        }
+
+        out.println(AnsiStyle.dim("\n  Goodbye! 👋\n"));
     }
 
-            // 检查斜杠命令
+    // ==================== 公共输入处理 ====================
+
+    /** 处理用户输入（命令分发或 Agent 调用） */
+    private void handleInput(String input, CommandContext cmdContext) {
+        // 斜杠命令
         if (commandRegistry.isCommand(input)) {
             var result = commandRegistry.dispatch(input, cmdContext);
             result.ifPresent(out::println);
             out.println();
-                continue;
+            return;
         }
 
-            // 调用 Agent 循环
+        // Agent 循环
         try {
             spinner.start("Thinking...");
             String response = agentLoop.run(input);
@@ -116,9 +223,6 @@ public class ReplSession {
         }
     }
 
-        out.println(AnsiStyle.dim("\n  Goodbye! 👋\n"));
-    }
-
     public void stop() {
         running = false;
     }