package cmd

import (
	"fmt"
	"os"
	"path/filepath"
	"strconv"

	"code.gitea.io/sdk/gitea"
	"forgejo.zerova.net/public/fgj-sid/internal/api"
	"forgejo.zerova.net/public/fgj-sid/internal/config"
	"forgejo.zerova.net/public/fgj-sid/internal/text"
	"github.com/spf13/cobra"
)

var releaseAssetCmd = &cobra.Command{
	Use:     "asset",
	Aliases: []string{"assets"},
	Short:   "Manage release assets",
	Long:    "List, upload, and delete individual attachments on a release.",
}

var releaseAssetListCmd = &cobra.Command{
	Use:   "list <tag|latest>",
	Short: "List release assets",
	Long:  "List attachments on a release identified by tag name (or \"latest\").",
	Example: `  # List assets on a release
  fgj release asset list v1.0.0

  # List assets on the latest release as JSON
  fgj release asset list latest --json`,
	Args: cobra.ExactArgs(1),
	RunE: runReleaseAssetList,
}

var releaseAssetCreateCmd = &cobra.Command{
	Use:   "create <tag|latest> <files...>",
	Short: "Upload one or more release assets",
	Long:  "Upload one or more files as attachments to an existing release.",
	Example: `  # Upload a single asset
  fgj release asset create v1.0.0 dist/app-linux-amd64

  # Upload multiple assets to the latest release
  fgj release asset create latest dist/*.tar.gz

  # Upload a single file under a different name
  fgj release asset create v1.0.0 ./build/out --name app-v1.0.0`,
	Args: cobra.MinimumNArgs(2),
	RunE: runReleaseAssetCreate,
}

var releaseAssetDeleteCmd = &cobra.Command{
	Use:   "delete <tag|latest> <asset-id-or-name>...",
	Short: "Delete one or more release assets",
	Long:  "Delete attachments from a release. Each argument may be a numeric asset ID or an asset filename.",
	Example: `  # Delete by filename
  fgj release asset delete v1.0.0 app-linux-amd64

  # Delete multiple by ID
  fgj release asset delete v1.0.0 42 43

  # Skip confirmation
  fgj release asset delete latest output.zip --yes`,
	Args: cobra.MinimumNArgs(2),
	RunE: runReleaseAssetDelete,
}

func init() {
	releaseCmd.AddCommand(releaseAssetCmd)
	releaseAssetCmd.AddCommand(releaseAssetListCmd)
	releaseAssetCmd.AddCommand(releaseAssetCreateCmd)
	releaseAssetCmd.AddCommand(releaseAssetDeleteCmd)

	addRepoFlags(releaseAssetListCmd)
	addJSONFlags(releaseAssetListCmd, "Output assets as JSON")

	addRepoFlags(releaseAssetCreateCmd)
	releaseAssetCreateCmd.Flags().String("name", "", "Override the uploaded filename (single file only)")

	addRepoFlags(releaseAssetDeleteCmd)
	releaseAssetDeleteCmd.Flags().BoolP("yes", "y", false, "Skip confirmation prompt")
}

func runReleaseAssetList(cmd *cobra.Command, args []string) error {
	tag := args[0]

	client, owner, name, err := newReleaseAssetClient(cmd)
	if err != nil {
		return err
	}

	ios.StartSpinner("Fetching release...")
	release, err := getReleaseByTagOrLatest(client, owner, name, tag)
	if err != nil {
		ios.StopSpinner()
		return err
	}

	var all []*gitea.Attachment
	for page := 1; ; page++ {
		attachments, _, err := client.ListReleaseAttachments(owner, name, release.ID, gitea.ListReleaseAttachmentsOptions{
			ListOptions: gitea.ListOptions{Page: page, PageSize: 50},
		})
		if err != nil {
			ios.StopSpinner()
			return fmt.Errorf("failed to list release assets: %w", err)
		}
		if len(attachments) == 0 {
			break
		}
		all = append(all, attachments...)
	}
	ios.StopSpinner()

	if wantJSON(cmd) {
		return outputJSON(cmd, all)
	}

	if len(all) == 0 {
		fmt.Fprintf(ios.Out, "No assets on release %s\n", release.TagName)
		return nil
	}

	isTTY := ios.IsStdoutTTY()
	tp := ios.NewTablePrinter()
	tp.AddHeader("ID", "NAME", "SIZE", "DOWNLOADS", "CREATED")
	for _, a := range all {
		tp.AddRow(
			strconv.FormatInt(a.ID, 10),
			a.Name,
			humanSize(a.Size),
			strconv.FormatInt(a.DownloadCount, 10),
			text.FormatDate(a.Created, isTTY),
		)
	}
	return tp.Render()
}

func runReleaseAssetCreate(cmd *cobra.Command, args []string) error {
	tag := args[0]
	files := args[1:]

	nameOverride, _ := cmd.Flags().GetString("name")
	if nameOverride != "" && len(files) != 1 {
		return fmt.Errorf("--name may only be used when uploading a single file")
	}

	// Fail early if any file is missing.
	for _, f := range files {
		info, err := os.Stat(f)
		if err != nil {
			return fmt.Errorf("failed to stat %s: %w", f, err)
		}
		if info.IsDir() {
			return fmt.Errorf("%s is a directory, not a file", f)
		}
	}

	client, owner, name, err := newReleaseAssetClient(cmd)
	if err != nil {
		return err
	}

	ios.StartSpinner("Fetching release...")
	release, err := getReleaseByTagOrLatest(client, owner, name, tag)
	ios.StopSpinner()
	if err != nil {
		return err
	}

	cs := ios.ColorScheme()
	for _, file := range files {
		filename := filepath.Base(file)
		if nameOverride != "" {
			filename = nameOverride
		}

		handle, err := os.Open(file)
		if err != nil {
			return fmt.Errorf("failed to open %s: %w", file, err)
		}

		attachment, _, uploadErr := client.CreateReleaseAttachment(owner, name, release.ID, handle, filename)
		closeErr := handle.Close()
		if uploadErr != nil {
			return fmt.Errorf("failed to upload %s: %w", file, uploadErr)
		}
		if closeErr != nil {
			return fmt.Errorf("failed to close %s: %w", file, closeErr)
		}

		fmt.Fprintf(ios.Out, "%s Uploaded %s (id %d, %s)\n", cs.SuccessIcon(), attachment.Name, attachment.ID, humanSize(attachment.Size))
	}

	return nil
}

func runReleaseAssetDelete(cmd *cobra.Command, args []string) error {
	tag := args[0]
	targets := args[1:]
	skipConfirm, _ := cmd.Flags().GetBool("yes")

	client, owner, name, err := newReleaseAssetClient(cmd)
	if err != nil {
		return err
	}

	ios.StartSpinner("Fetching release...")
	release, err := getReleaseByTagOrLatest(client, owner, name, tag)
	ios.StopSpinner()
	if err != nil {
		return err
	}

	// Resolve each target to an attachment (ID + name). List attachments once
	// if any target is a non-numeric name so we can match by filename.
	var cached []*gitea.Attachment
	resolvedIDs := make([]int64, 0, len(targets))
	resolvedNames := make([]string, 0, len(targets))

	for _, t := range targets {
		if id, err := strconv.ParseInt(t, 10, 64); err == nil && id > 0 {
			resolvedIDs = append(resolvedIDs, id)
			resolvedNames = append(resolvedNames, t)
			continue
		}

		if cached == nil {
			cached, err = listReleaseAttachments(client, owner, name, release.ID)
			if err != nil {
				return err
			}
		}

		var matched *gitea.Attachment
		for _, a := range cached {
			if a.Name == t {
				matched = a
				break
			}
		}
		if matched == nil {
			return fmt.Errorf("no asset named %q on release %s", t, release.TagName)
		}
		resolvedIDs = append(resolvedIDs, matched.ID)
		resolvedNames = append(resolvedNames, matched.Name)
	}

	cs := ios.ColorScheme()
	for i, id := range resolvedIDs {
		display := resolvedNames[i]

		if !skipConfirm && ios.IsStdinTTY() {
			answer, err := promptLine(fmt.Sprintf("Delete asset %s (id %d) from release %s? [y/N]: ", display, id, release.TagName))
			if err != nil {
				return err
			}
			if answer != "y" && answer != "Y" && answer != "yes" {
				fmt.Fprintf(ios.ErrOut, "Skipped %s\n", display)
				continue
			}
		}

		if _, err := client.DeleteReleaseAttachment(owner, name, release.ID, id); err != nil {
			return fmt.Errorf("failed to delete asset %s: %w", display, err)
		}

		fmt.Fprintf(ios.Out, "%s Deleted asset %s (id %d)\n", cs.SuccessIcon(), display, id)
	}

	return nil
}

func newReleaseAssetClient(cmd *cobra.Command) (*api.Client, string, string, error) {
	repo, _ := cmd.Flags().GetString("repo")
	owner, name, err := parseRepo(repo)
	if err != nil {
		return nil, "", "", err
	}

	cfg, err := config.Load()
	if err != nil {
		return nil, "", "", err
	}

	client, err := api.NewClientFromConfig(cfg, "", getDetectedHost(), getCwd())
	if err != nil {
		return nil, "", "", err
	}

	return client, owner, name, nil
}

// humanSize formats a byte count using power-of-1024 units.
func humanSize(n int64) string {
	const unit = int64(1024)
	if n < unit {
		return fmt.Sprintf("%d B", n)
	}
	div, exp := unit, 0
	for v := n / unit; v >= unit; v /= unit {
		div *= unit
		exp++
	}
	suffixes := []string{"KB", "MB", "GB", "TB", "PB", "EB"}
	if exp >= len(suffixes) {
		exp = len(suffixes) - 1
	}
	return fmt.Sprintf("%.1f %s", float64(n)/float64(div), suffixes[exp])
}