# minimal_agent.py
import os
from anthropic import Anthropic
from dotenv import load_dotenv

load_dotenv()
client = Anthropic()

# --- ツール 3 つ ---
def read_file(path: str) -> str:
    with open(path) as f:
        return f.read()

def list_dir(path: str = ".") -> str:
    import os
    return "\n".join(os.listdir(path))

def run_python(code: str) -> str:
    import subprocess
    r = subprocess.run(["python", "-c", code], capture_output=True, text=True, timeout=10)
    return f"stdout:\n{r.stdout}\nstderr:\n{r.stderr}"

TOOLS = [
    {"name": "read_file",  "description": "ファイルを読む", "input_schema": {"type": "object", "properties": {"path": {"type": "string"}}, "required": ["path"]}},
    {"name": "list_dir",   "description": "ディレクトリ一覧", "input_schema": {"type": "object", "properties": {"path": {"type": "string"}}}},
    {"name": "run_python", "description": "Python コードを実行", "input_schema": {"type": "object", "properties": {"code": {"type": "string"}}, "required": ["code"]}},
]
TOOL_FUNCS = {"read_file": read_file, "list_dir": list_dir, "run_python": run_python}

# --- ReAct ループ ---
def run_agent(question: str, max_iter: int = 5):
    messages = [{"role": "user", "content": question}]
    for it in range(max_iter):
        resp = client.messages.create(
            model="claude-haiku-4-5",
            max_tokens=2000,
            tools=TOOLS,
            messages=messages,
        )
        if resp.stop_reason == "end_turn":
            return next((b.text for b in resp.content if b.type == "text"), "")
        # tool 実行
        tool_results = []
        for b in resp.content:
            if b.type == "tool_use":
                fn = TOOL_FUNCS[b.name]
                try:
                    result = fn(**b.input)
                except Exception as e:
                    result = f"Error: {e}"
                tool_results.append({"type": "tool_result", "tool_use_id": b.id, "content": str(result)})
        messages.append({"role": "assistant", "content": resp.content})
        messages.append({"role": "user", "content": tool_results})
    return "(max iterations reached)"

if __name__ == "__main__":
    print(run_agent("カレントディレクトリのファイル一覧を見て、Python ファイルがあれば最初の 1 つを読んで概要を 3 行で説明して"))

from claude_agent_sdk import Agent

agent = Agent(model="claude-haiku-4-5", system="あなたはコードを読む専門家です。")
agent.add_tool(read_file)
agent.add_tool(list_dir)

result = agent.run("カレントの Python ファイル概要を出して")
print(result)

claude --print "PR #123 のセキュリティ観点をレビューして" > review.md

- name: Auto PR Review
  run: |
    npm install -g @anthropic-ai/claude-code
    claude --print "diff を読んでセキュリティ観点で気になる点を Markdown で出して" > review.md
  env:
    ANTHROPIC_API_KEY: ${{ secrets.ANTHROPIC_API_KEY }}
- run: gh pr comment ${{ github.event.pull_request.number }} --body-file review.md

                                          ┌──────────────────┐
                                          │ Claude Code 本体 │
                                          └─────────┬────────┘
   ┌──────────┐   ┌───────┐   ┌───────┐  │
   │CLAUDE.md │ + │Skills │ + │Hooks  │ →│ カスタマイズ
   └──────────┘   └───────┘   └───────┘  │
        ↑                                  │
        +「素の API」                      │
        ↓                                  ▼
   ┌─────────────────┐           ┌─────────────────┐
   │自前 ReAct ループ│ ← SDK →   │ Agent SDK ラップ│
   └─────────────────┘           └─────────────────┘
   (第6章で学んだもの)            (第8-05 で学んだもの)