# 反模式：每增加一个工具，就要修改一次 agent_loop 核心循环代码
if block.name == "bash":
    output = run_bash(block.input["command"])
elif block.name == "read_file":
    output = run_read(block.input["path"])
elif block.name == "write_file":
    output = run_write(block.input["path"], block.input["content"])

# 优雅设计：Dispatch Map 路由
TOOL_HANDLERS = {
    "bash": lambda **kw: run_bash(kw["command"]),
    "read_file": lambda **kw: run_read_file(kw["path"], kw.get("limit", 200)),
    "write_file": lambda **kw: run_write_file(kw["path"], kw["content"]),
    "edit_file": lambda **kw: run_edit_file(kw["path"], kw["old_string"], kw["new_string"]),
}

# 循环体内一行搞定分发：
handler = TOOL_HANDLERS.get(block.name)
output = handler(**block.input) if handler else f"Error: 未知工具 {block.name}"

import os
import subprocess

WORKSPACE_ROOT = os.path.abspath("./workspace")

def validate_safe_path(rel_path: str) -> str:
    """物理路径沙箱校验：严格禁止跳出工作区根目录"""
    full_path = os.path.abspath(os.path.join(WORKSPACE_ROOT, rel_path))
    if not full_path.startswith(WORKSPACE_ROOT):
        raise PermissionError(f"越权访问阻断：路径 '{rel_path}' 试图跳出工作区根目录！")
    return full_path

def run_read_file(path: str, limit: int = 200) -> str:
    """支持行号显示与上限保护的文件读取"""
    try:
        real_path = validate_safe_path(path)
        if not os.path.exists(real_path):
            return f"Error: 文件 '{path}' 不存在。"
        
        with open(real_path, "r", encoding="utf-8", errors="replace") as f:
            lines = f.readlines()
        
        total = len(lines)
        sliced = lines[:limit]
        numbered = [f"{i+1:4d} | {line}" for i, line in enumerate(sliced)]
        
        res = "".join(numbered)
        if total > limit:
            res += f"\n... [已截断，后续仍有 {total - limit} 行未展示] ..."
        return res
    except Exception as e:
        return f"读取文件失败: {str(e)}"

def run_write_file(path: str, content: str) -> str:
    """全量创建或覆盖文件"""
    try:
        real_path = validate_safe_path(path)
        os.makedirs(os.path.dirname(real_path), exist_ok=True)
        with open(real_path, "w", encoding="utf-8") as f:
            f.write(content)
        return f"成功写入文件 '{path}'（共 {len(content)} 字符）。"
    except Exception as e:
        return f"写入文件失败: {str(e)}"

def run_edit_file(path: str, old_string: str, new_string: str) -> str:
    """
    精确局部替换：必须命中唯一目标段落，拒绝任何不确定的模糊替换
    """
    try:
        real_path = validate_safe_path(path)
        if not os.path.exists(real_path):
            return f"Error: 目标文件 '{path}' 不存在。"
        
        with open(real_path, "r", encoding="utf-8") as f:
            content = f.read()
        
        count = content.count(old_string)
        if count == 0:
            return f"替换失败：在 '{path}' 中未找到待匹配的 old_string。请检查缩进或先调用 read_file 核对最新内容。"
        if count > 1:
            return f"替换失败：在 '{path}' 中找到了 {count} 处匹配段落，存在歧义！请增加上下文行使其具有唯一性。"
        
        new_content = content.replace(old_string, new_string, 1)
        with open(real_path, "w", encoding="utf-8") as f:
            f.write(new_content)
        
        return f"成功在 '{path}' 中完成精确替换。"
    except Exception as e:
        return f"编辑文件失败: {str(e)}"