package tool

import (
	"bytes"
	"context"
	"fmt"
	"log/slog"
	"os/exec"
	"strconv"

	"github.com/mark3labs/mcp-go/mcp"
	"github.com/mark3labs/mcp-go/server"
)

// DockerTool 提供 docker logs 查询。
type DockerTool struct{}

func NewDockerTool() *DockerTool {
	return &DockerTool{}
}

func (d *DockerTool) Name() string        { return "docker" }
func (d *DockerTool) Description() string { return "Docker 容器日志查询" }

func (d *DockerTool) Initialize(_ context.Context) error {
	if _, err := exec.LookPath("docker"); err != nil {
		return fmt.Errorf("docker CLI not found: %w", err)
	}
	slog.Info("docker CLI ready")
	return nil
}

func (d *DockerTool) Shutdown(_ context.Context) error { return nil }

func (d *DockerTool) HealthCheck(ctx context.Context) error {
	return exec.CommandContext(ctx, "docker", "version").Run()
}

func (d *DockerTool) Register(mcpServer *server.MCPServer) error {
	mcpServer.AddTool(mcp.NewTool("docker_logs",
		mcp.WithDescription("获取 Docker 容器日志，等价于 docker logs --tail N <container>"),
		mcp.WithString("container",
			mcp.Required(),
			mcp.Description("容器名称或 ID"),
		),
		mcp.WithNumber("tail",
			mcp.Description("返回最后 N 行日志，默认 100"),
		),
	), d.handleLogs)

	return nil
}

func (d *DockerTool) handleLogs(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	args := getArgs(req)
	container, _ := args["container"].(string)
	if container == "" {
		return mcp.NewToolResultError("container 参数必填"), nil
	}

	tail := 100
	if t, ok := args["tail"].(float64); ok && t > 0 {
		tail = int(t)
	}

	cmd := exec.CommandContext(ctx, "docker", "logs",
		"--tail", strconv.Itoa(tail),
		"--timestamps",
		container,
	)

	var stdout, stderr bytes.Buffer
	cmd.Stdout = &stdout
	cmd.Stderr = &stderr

	if err := cmd.Run(); err != nil {
		return mcp.NewToolResultError(
			fmt.Sprintf("docker logs 失败: %v\n%s", err, stderr.String()),
		), nil
	}

	output := stdout.String()
	if output == "" {
		output = "(容器没有日志输出)"
	}

	return mcp.NewToolResultText(output), nil
}