"""文件读取工具"""


# ════════════════════════════════════════════════════════════════
# tools/file_reader.py   —   文件读取工具
# ════════════════════════════════════════════════════════════════
"""
tools/file_reader.py
本地文件读取工具，支持文本文件，限制读取路径防止越权
"""

from pathlib import Path
from tools.base_tool import BaseTool, ToolResult


# 允许读取的根目录（沙箱限制）
_ALLOWED_ROOT = Path("./workspace")


class FileReaderTool(BaseTool):
    name        = "file_reader"
    description = "读取本地文件内容，仅限 workspace/ 目录下的文件"
    parameters  = {
        "path": {
            "type":        "string",
            "description": "文件路径，相对于 workspace/ 目录",
        },
        "encoding": {
            "type":        "string",
            "description": "文件编码，默认 utf-8",
        },
    }

    def execute(self, path: str, encoding: str = "utf-8", **_) -> ToolResult:
        _ALLOWED_ROOT.mkdir(exist_ok=True)

        # 路径安全检查：防止目录穿越攻击
        target = (_ALLOWED_ROOT / path).resolve()
        if not str(target).startswith(str(_ALLOWED_ROOT.resolve())):
            return ToolResult(success=False, output=f"❌ 拒绝访问: 路径超出允许范围")

        if not target.exists():
            # Demo 模式：自动创建示例文件
            self._create_demo_file(target)

        try:
            content = target.read_text(encoding=encoding)
            return ToolResult(
                success=True,
                output=f"文件 [{path}] 内容:\n{content}",
                metadata={"path": str(target), "size": target.stat().st_size},
            )
        except OSError as exc:
            return ToolResult(success=False, output=f"读取失败: {exc}")

    @staticmethod
    def _create_demo_file(path: Path) -> None:
        """自动创建演示用文件"""
        path.parent.mkdir(parents=True, exist_ok=True)
        path.write_text(
            '{\n  "app": "AgentDemo",\n  "version": "1.0.0",\n'
            '  "llm": "claude-sonnet-4-6",\n  "tools": ["calculator", "web_search"]\n}\n',
            encoding="utf-8",
        )