package credhelper

import (
	"fmt"
	"os"
	"sort"

	"github.com/charmbracelet/huh"
	"github.com/spf13/cobra"
)

func newSwitchCmd() *cobra.Command {
	return &cobra.Command{
		Use:   "switch [registry]",
		Short: "Switch the active account for a registry",
		Long:  "Switch the active account used for Docker operations.\nDefault registry: " + cfg.DefaultRegistry,
		Args:  cobra.MaximumNArgs(1),
		RunE:  runSwitch,
	}
}

func runSwitch(cmd *cobra.Command, args []string) error {
	serverURL := cfg.DefaultRegistry
	if len(args) > 0 {
		serverURL = args[0]
	}

	appViewURL := buildAppViewURL(serverURL)

	sc, err := loadConfigForWrite()
	if err != nil {
		return err
	}

	reg := sc.findRegistry(appViewURL)
	if reg == nil || len(reg.Accounts) == 0 {
		fmt.Fprintf(os.Stderr, "No accounts configured for %s.\n", serverURL)
		fmt.Fprintf(os.Stderr, "Run: %s login\n", cfg.BinaryName)
		return nil
	}

	if len(reg.Accounts) == 1 {
		for _, acct := range reg.Accounts {
			fmt.Fprintf(os.Stderr, "Only one account (%s) — nothing to switch.\n", acct.Handle)
		}
		return nil
	}

	// For exactly 2 accounts, just toggle
	if len(reg.Accounts) == 2 {
		active := reg.activeAccount()
		for _, acct := range reg.Accounts {
			if acct != active {
				reg.setActive(acct)
				if err := sc.save(); err != nil {
					return fmt.Errorf("saving config: %w", err)
				}
				fmt.Printf("Switched to %s on %s\n", acct.Handle, serverURL)
				return nil
			}
		}
	}

	// 3+ accounts: interactive select. Options display the handle but carry the
	// account's key (DID) as the value.
	accts := make([]*Account, 0, len(reg.Accounts))
	for _, acct := range reg.Accounts {
		accts = append(accts, acct)
	}
	sort.Slice(accts, func(i, j int) bool { return accts[i].Handle < accts[j].Handle })

	active := reg.activeAccount()
	var options []huh.Option[string]
	for _, acct := range accts {
		label := acct.Handle
		if acct == active {
			label += " (current)"
		}
		options = append(options, huh.NewOption(label, acct.key()))
	}

	var selected string
	err = huh.NewSelect[string]().
		Title("Select account for " + serverURL).
		Options(options...).
		Value(&selected).
		Run()
	if err != nil {
		return err
	}

	reg.Active = selected
	if err := sc.save(); err != nil {
		return fmt.Errorf("saving config: %w", err)
	}

	label := selected
	if acct := reg.find(selected); acct != nil {
		label = acct.Handle
	}
	fmt.Printf("Switched to %s on %s\n", label, serverURL)
	return nil
}