package cli

import (
	"bytes"
	"fmt"
	"os"
	"sort"

	"github.com/codeclysm/extract"
	"golang.org/x/xerrors"

	"github.com/coder/coder/cli/clibase"
	"github.com/coder/coder/cli/cliui"
	"github.com/coder/coder/codersdk"
)

func (r *RootCmd) templatePull() *clibase.Cmd {
	var tarMode bool

	client := new(codersdk.Client)
	cmd := &clibase.Cmd{
		Use:   "pull <name> [destination]",
		Short: "Download the latest version of a template to a path.",
		Middleware: clibase.Chain(
			clibase.RequireRangeArgs(1, 2),
			r.InitClient(client),
		),
		Handler: func(inv *clibase.Invocation) error {
			var (
				ctx          = inv.Context()
				templateName = inv.Args[0]
				dest         string
			)

			if len(inv.Args) > 1 {
				dest = inv.Args[1]
			}

			// TODO(JonA): Do we need to add a flag for organization?
			organization, err := CurrentOrganization(inv, client)
			if err != nil {
				return xerrors.Errorf("current organization: %w", err)
			}

			template, err := client.TemplateByName(ctx, organization.ID, templateName)
			if err != nil {
				return xerrors.Errorf("template by name: %w", err)
			}

			// Pull the versions for the template. We'll find the latest
			// one and download the source.
			versions, err := client.TemplateVersionsByTemplate(ctx, codersdk.TemplateVersionsByTemplateRequest{
				TemplateID: template.ID,
			})
			if err != nil {
				return xerrors.Errorf("template versions by template: %w", err)
			}

			if len(versions) == 0 {
				return xerrors.Errorf("no template versions for template %q", templateName)
			}

			// Sort the slice from newest to oldest template.
			sort.SliceStable(versions, func(i, j int) bool {
				return versions[i].CreatedAt.After(versions[j].CreatedAt)
			})

			latest := versions[0]

			// Download the tar archive.
			raw, ctype, err := client.Download(ctx, latest.Job.FileID)
			if err != nil {
				return xerrors.Errorf("download template: %w", err)
			}

			if ctype != codersdk.ContentTypeTar {
				return xerrors.Errorf("unexpected Content-Type %q, expecting %q", ctype, codersdk.ContentTypeTar)
			}

			if tarMode {
				_, err = inv.Stdout.Write(raw)
				return err
			}

			if dest == "" {
				dest = templateName + "/"
			}

			err = os.MkdirAll(dest, 0o750)
			if err != nil {
				return xerrors.Errorf("mkdirall %q: %w", dest, err)
			}

			ents, err := os.ReadDir(dest)
			if err != nil {
				return xerrors.Errorf("read dir %q: %w", dest, err)
			}

			if len(ents) > 0 {
				_, err = cliui.Prompt(inv, cliui.PromptOptions{
					Text:      fmt.Sprintf("Directory %q is not empty, existing files may be overwritten.\nContinue extracting?", dest),
					Default:   "No",
					Secret:    false,
					IsConfirm: true,
				})
				if err != nil {
					return err
				}
			}

			_, _ = fmt.Fprintf(inv.Stderr, "Extracting template to %q\n", dest)
			err = extract.Tar(ctx, bytes.NewReader(raw), dest, nil)
			return err
		},
	}

	cmd.Options = clibase.OptionSet{
		{
			Description: "Output the template as a tar archive to stdout.",
			Flag:        "tar",

			Value: clibase.BoolOf(&tarMode),
		},
		cliui.SkipPromptOption(),
	}

	return cmd
}