package cmd

import (
	"fmt"
	"log/slog"

	"github.com/portainer/kubesolo-os/update/pkg/image"
	"github.com/portainer/kubesolo-os/update/pkg/partition"
)

// Apply downloads a new OS image and writes it to the passive partition.
// It does NOT activate the new partition — use 'activate' for that.
func Apply(args []string) error {
	opts := parseOpts(args)

	if opts.ServerURL == "" {
		return fmt.Errorf("--server is required")
	}

	env := opts.NewBootEnv()

	// Determine passive slot
	passiveSlot, err := env.PassiveSlot()
	if err != nil {
		return fmt.Errorf("reading passive slot: %w", err)
	}

	slog.Info("applying update", "target_slot", passiveSlot)

	// Check for update
	stageDir := "/tmp/kubesolo-update-stage"
	client := image.NewClient(opts.ServerURL, stageDir)
	defer client.Cleanup()

	// Enable signature verification if public key is configured
	if opts.PubKeyPath != "" {
		client.SetPublicKeyPath(opts.PubKeyPath)
		slog.Info("signature verification enabled", "pubkey", opts.PubKeyPath)
	}

	meta, err := client.CheckForUpdate()
	if err != nil {
		return fmt.Errorf("checking for update: %w", err)
	}

	slog.Info("update available", "version", meta.Version)

	// Download and verify
	staged, err := client.Download(meta)
	if err != nil {
		return fmt.Errorf("downloading update: %w", err)
	}

	// Mount passive partition
	partInfo, err := partition.GetSlotPartition(passiveSlot)
	if err != nil {
		return fmt.Errorf("finding passive partition: %w", err)
	}

	mountPoint := "/tmp/kubesolo-passive-" + passiveSlot
	if err := partition.MountReadWrite(partInfo.Device, mountPoint); err != nil {
		return fmt.Errorf("mounting passive partition: %w", err)
	}
	defer partition.Unmount(mountPoint)

	// Write image to passive partition
	if err := partition.WriteSystemImage(mountPoint, staged.VmlinuzPath, staged.InitramfsPath, staged.Version); err != nil {
		return fmt.Errorf("writing system image: %w", err)
	}

	fmt.Printf("Update v%s written to slot %s (%s)\n", staged.Version, passiveSlot, partInfo.Device)
	fmt.Println("Run 'kubesolo-update activate' to boot into the new version")

	return nil
}