package commands

import (
	"fmt"
	"os"

	"git.dws.rip/DWS/onyx/internal/core"
	"github.com/spf13/cobra"
)

// NewSwitchCmd creates the switch command
func NewSwitchCmd() *cobra.Command {
	cmd := &cobra.Command{
		Use:   "switch <name>",
		Short: "Switch to a different workstream",
		Long: `Switch to a different workstream.

This command will:
  1. Save the current ephemeral state (handled by the daemon)
  2. Load the target workstream
  3. Checkout the latest commit in the target workstream
  4. Update the current workstream pointer
  5. Restore the workspace state

The operation is logged to the action log, so you can undo it if needed.`,
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			return runSwitch(args[0])
		},
	}

	return cmd
}

// runSwitch executes the switch command
func runSwitch(name string) error {
	// Get current directory
	cwd, err := os.Getwd()
	if err != nil {
		return fmt.Errorf("failed to get current directory: %w", err)
	}

	// Check if this is an Onyx repository
	if !core.IsOnyxRepo(cwd) {
		return fmt.Errorf("not an Onyx repository")
	}

	// Open the repository
	repo, err := core.Open(cwd)
	if err != nil {
		return fmt.Errorf("failed to open repository: %w", err)
	}
	defer repo.Close()

	// Create workstream manager
	wsManager := core.NewWorkstreamManager(repo)

	// Get current workstream name before switching
	currentName, err := wsManager.GetCurrentWorkstreamName()
	if err != nil {
		currentName = "none"
	}

	// Check if we're already on the target workstream
	if currentName == name {
		fmt.Printf("Already on workstream '%s'\n", name)
		return nil
	}

	// Use ExecuteWithTransaction to capture state_before and state_after
	err = core.ExecuteWithTransaction(repo, "switch", fmt.Sprintf("Switched from '%s' to '%s'", currentName, name), func() error {
		return wsManager.SwitchWorkstream(name)
	})

	if err != nil {
		return err
	}

	// Get the workstream we just switched to
	targetWorkstream, err := wsManager.GetCurrentWorkstream()
	if err != nil {
		return fmt.Errorf("failed to get workstream after switch: %w", err)
	}

	// Display success message
	fmt.Printf("Switched to workstream '%s'\n", name)

	// Show workstream info
	commitCount := targetWorkstream.GetCommitCount()
	if commitCount == 0 {
		fmt.Printf("\nThis is a new workstream based on '%s' with no commits yet.\n", targetWorkstream.BaseBranch)
		fmt.Printf("Make changes and save them with 'onx save -m \"message\"'\n")
	} else {
		commitText := "commit"
		if commitCount != 1 {
			commitText = "commits"
		}
		fmt.Printf("\nThis workstream has %d %s.\n", commitCount, commitText)

		// Show the latest commit
		if latestCommit, err := targetWorkstream.GetLatestCommit(); err == nil {
			fmt.Printf("Latest commit: %s\n", latestCommit.Message)
		}
	}

	return nil
}