package cmd

import (
	_ "embed"
	"log/slog"
	"os"

	"github.com/modelcontextprotocol/go-sdk/mcp"
	"github.com/spf13/cobra"
	"google.golang.org/adk/agent"
	"google.golang.org/adk/agent/llmagent"
	"google.golang.org/adk/cmd/launcher"
	"google.golang.org/adk/cmd/launcher/full"
	"google.golang.org/adk/model/gemini"
	"google.golang.org/adk/tool"
	"google.golang.org/adk/tool/mcptoolset"
	"google.golang.org/genai"
)

const (
	agentShort = "Start agent to automate YouTube workflows"
	agentLong  = "Start agent to automate YouTube workflows"
)

var (
	//go:embed INSTRUCTION.md
	instruction string
)

var agentCmd = &cobra.Command{
	Use:   "agent",
	Short: agentShort,
	Long:  agentLong,
	PreRun: func(cmd *cobra.Command, args []string) {
		envInstruction, ok := os.LookupEnv("YUTU_AGENT_INSTRUCTION")
		if ok && envInstruction != "" {
			instruction = envInstruction
		}
	},
	Run: func(cmd *cobra.Command, args []string) {
		ctx := cmd.Context()
		m, err := gemini.NewModel(
			ctx, os.Getenv("GEMINI_MODEL"), &genai.ClientConfig{
				APIKey:  os.Getenv("GEMINI_API_KEY"),
				Backend: genai.BackendGeminiAPI,
			},
		)
		if err != nil {
			slog.ErrorContext(ctx, "failed to create Gemini model", "error", err)
			os.Exit(1)
		}

		clientTransport, serverTransport := mcp.NewInMemoryTransports()
		_, err = Server.Connect(ctx, serverTransport, nil)
		if err != nil {
			slog.ErrorContext(ctx, "failed to connect to MCP server", "error", err)
			os.Exit(1)
		}

		mcpToolSet, err := mcptoolset.New(
			mcptoolset.Config{
				Transport: clientTransport,
			},
		)
		if err != nil {
			slog.ErrorContext(ctx, "failed to create MCP tool set", "error", err)
		}

		a, err := llmagent.New(
			llmagent.Config{
				Model:       m,
				Name:        "YouTube Copilot",
				Instruction: instruction,
				Toolsets:    []tool.Toolset{mcpToolSet},
			},
		)
		if err != nil {
			slog.ErrorContext(ctx, "failed to create LLM agent", "error", err)
			os.Exit(1)
		}

		config := &launcher.Config{
			AgentLoader: agent.NewSingleLoader(a),
		}
		l := full.NewLauncher()
		if err := l.Execute(ctx, config, os.Args[2:]); err != nil {
			slog.ErrorContext(
				ctx, "failed to launch agent",
				"launch", l.CommandLineSyntax(), "error", err,
			)
			os.Exit(1)
		}
	},
}

func init() {
	RootCmd.AddCommand(agentCmd)
}