package extension

import (
	"errors"
	"fmt"
	gio "io"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/MakeNowJust/heredoc"
	"github.com/cli/cli/v2/api"
	"github.com/cli/cli/v2/git"
	"github.com/cli/cli/v2/internal/featuredetection"
	"github.com/cli/cli/v2/internal/ghrepo"
	"github.com/cli/cli/v2/internal/tableprinter"
	"github.com/cli/cli/v2/internal/text"
	"github.com/cli/cli/v2/pkg/cmd/extension/browse"
	"github.com/cli/cli/v2/pkg/cmdutil"
	"github.com/cli/cli/v2/pkg/extensions"
	"github.com/cli/cli/v2/pkg/search"
	"github.com/spf13/cobra"
)

var alreadyInstalledError = errors.New("alreadyInstalledError")

func NewCmdExtension(f *cmdutil.Factory) *cobra.Command {
	m := f.ExtensionManager
	io := f.IOStreams
	gc := f.GitClient
	prompter := f.Prompter
	config := f.Config
	browser := f.Browser
	httpClient := f.HttpClient

	extCmd := cobra.Command{
		Use:   "extension",
		Short: "Manage gh extensions",
		Long: heredoc.Docf(`
			GitHub CLI extensions are repositories that provide additional gh commands.

			The name of the extension repository must start with %[1]sgh-%[1]s and it must contain an
			executable of the same name. All arguments passed to the %[1]sgh <extname>%[1]s invocation
			will be forwarded to the %[1]sgh-<extname>%[1]s executable of the extension.

			An extension cannot override any of the core gh commands. If an extension name conflicts
			with a core gh command, you can use %[1]sgh extension exec <extname>%[1]s.

			When an extension is executed, gh will check for new versions once every 24 hours and display
			an upgrade notice. See %[1]sgh help environment%[1]s for information on disabling extension notices.

			Extensions are not verified, signed, or endorsed by GitHub. When you install or upgrade
  			an extension, you are trusting its publisher. It is your responsibility to review the
  			source and provenance of any extension before use.

			For the list of available extensions, see <https://github.com/topics/gh-extension>.
		`, "`"),
		Aliases: []string{"extensions", "ext"},
	}

	upgradeFunc := func(name string, flagForce bool) error {
		cs := io.ColorScheme()
		err := m.Upgrade(name, flagForce)
		if err != nil {
			if name != "" {
				fmt.Fprintf(io.ErrOut, "%s Failed upgrading extension %s: %s\n", cs.FailureIcon(), name, err)
			} else if errors.Is(err, noExtensionsInstalledError) {
				return cmdutil.NewNoResultsError("no installed extensions found")
			} else {
				fmt.Fprintf(io.ErrOut, "%s Failed upgrading extensions\n", cs.FailureIcon())
			}
			return cmdutil.SilentError
		}

		if io.IsStdoutTTY() {
			fmt.Fprintf(io.Out, "%s Successfully checked extension upgrades\n", cs.SuccessIcon())
		}

		return nil
	}

	extCmd.AddCommand(
		func() *cobra.Command {
			query := search.Query{
				Kind: search.KindRepositories,
			}
			qualifiers := search.Qualifiers{
				Topic: []string{"gh-extension"},
			}
			var order string
			var sort string
			var webMode bool
			var exporter cmdutil.Exporter

			cmd := &cobra.Command{
				Use:   "search [<query>]",
				Short: "Search extensions to the GitHub CLI",
				Long: heredoc.Docf(`
					Search for gh extensions.

					With no arguments, this command prints out the first 30 extensions
					available to install sorted by number of stars. More extensions can
					be fetched by specifying a higher limit with the %[1]s--limit%[1]s flag.

					When connected to a terminal, this command prints out three columns.
					The first has a ✓ if the extension is already installed locally. The
					second is the full name of the extension repository in %[1]sOWNER/REPO%[1]s
					format. The third is the extension's description.

					When not connected to a terminal, the ✓ character is rendered as the
					word "installed" but otherwise the order and content of the columns
					are the same.

					This command behaves similarly to %[1]sgh search repos%[1]s but does not
					support as many search qualifiers. For a finer grained search of
					extensions, try using:

						gh search repos --topic "gh-extension"

					and adding qualifiers as needed. See %[1]sgh help search repos%[1]s to learn
					more about repository search.

					For listing just the extensions that are already installed locally,
					see:

						gh ext list
				`, "`"),
				Example: heredoc.Doc(`
					# List the first 30 extensions sorted by star count, descending
					$ gh ext search

					# List more extensions
					$ gh ext search --limit 300

					# List extensions matching the term "branch"
					$ gh ext search branch

					# List extensions owned by organization "github"
					$ gh ext search --owner github

					# List extensions, sorting by recently updated, ascending
					$ gh ext search --sort updated --order asc

					# List extensions, filtering by license
					$ gh ext search --license MIT

					# Open search results in the browser
					$ gh ext search -w
				`),
				RunE: func(cmd *cobra.Command, args []string) error {
					cfg, err := config()
					if err != nil {
						return err
					}
					client, err := httpClient()
					if err != nil {
						return err
					}

					if cmd.Flags().Changed("order") {
						query.Order = order
					}
					if cmd.Flags().Changed("sort") {
						query.Sort = sort
					}

					query.Keywords = args
					query.Qualifiers = qualifiers

					host, _ := cfg.Authentication().DefaultHost()
					detector := featuredetection.NewDetector(client, host)
					searcher := search.NewSearcher(client, host, detector)

					if webMode {
						url := searcher.URL(query)
						if io.IsStdoutTTY() {
							fmt.Fprintf(io.ErrOut, "Opening %s in your browser.\n", text.DisplayURL(url))
						}
						return browser.Browse(url)
					}

					io.StartProgressIndicator()
					result, err := searcher.Repositories(query)
					io.StopProgressIndicator()
					if err != nil {
						return err
					}

					if exporter != nil {
						return exporter.Write(io, result.Items)
					}

					if io.IsStdoutTTY() {
						if len(result.Items) == 0 {
							return errors.New("no extensions found")
						}
						fmt.Fprintf(io.Out, "Showing %d of %d extensions\n", len(result.Items), result.Total)
						fmt.Fprintln(io.Out)
					}

					cs := io.ColorScheme()
					installedExts := m.List()

					isInstalled := func(repo search.Repository) bool {
						searchRepo, err := ghrepo.FromFullName(repo.FullName)
						if err != nil {
							return false
						}
						for _, e := range installedExts {
							// TODO consider a Repo() on Extension interface
							if u, err := git.ParseURL(e.URL()); err == nil {
								if r, err := ghrepo.FromURL(u); err == nil {
									if ghrepo.IsSame(searchRepo, r) {
										return true
									}
								}
							}
						}
						return false
					}

					tp := tableprinter.New(io, tableprinter.WithHeader("", "REPO", "DESCRIPTION"))
					for _, repo := range result.Items {
						if !strings.HasPrefix(repo.Name, "gh-") {
							continue
						}

						installed := ""
						if isInstalled(repo) {
							if io.IsStdoutTTY() {
								installed = "✓"
							} else {
								installed = "installed"
							}
						}

						tp.AddField(installed, tableprinter.WithColor(cs.Green))
						tp.AddField(repo.FullName, tableprinter.WithColor(cs.Bold))
						tp.AddField(repo.Description)
						tp.EndRow()
					}

					return tp.Render()
				},
			}

			// Output flags
			cmd.Flags().BoolVarP(&webMode, "web", "w", false, "Open the search query in the web browser")
			cmdutil.AddJSONFlags(cmd, &exporter, search.RepositoryFields)

			// Query parameter flags
			cmd.Flags().IntVarP(&query.Limit, "limit", "L", 30, "Maximum number of extensions to fetch")
			cmdutil.StringEnumFlag(cmd, &order, "order", "", "desc", []string{"asc", "desc"}, "Order of repositories returned, ignored unless '--sort' flag is specified")
			cmdutil.StringEnumFlag(cmd, &sort, "sort", "", "best-match", []string{"forks", "help-wanted-issues", "stars", "updated"}, "Sort fetched repositories")

			// Qualifier flags
			cmd.Flags().StringSliceVar(&qualifiers.License, "license", nil, "Filter based on license type")
			cmd.Flags().StringSliceVar(&qualifiers.User, "owner", nil, "Filter on owner")

			return cmd
		}(),
		&cobra.Command{
			Use:     "list",
			Short:   "List installed extension commands",
			Aliases: []string{"ls"},
			Args:    cobra.NoArgs,
			RunE: func(cmd *cobra.Command, args []string) error {
				cmds := m.List()
				if len(cmds) == 0 {
					return cmdutil.NewNoResultsError("no installed extensions found")
				}
				cs := io.ColorScheme()
				t := tableprinter.New(io, tableprinter.WithHeader("NAME", "REPO", "VERSION"))
				for _, c := range cmds {
					// TODO consider a Repo() on Extension interface
					var repo string
					if u, err := git.ParseURL(c.URL()); err == nil {
						if r, err := ghrepo.FromURL(u); err == nil {
							repo = ghrepo.FullName(r)
						}
					}

					t.AddField(fmt.Sprintf("gh %s", c.Name()))
					t.AddField(repo)
					version := displayExtensionVersion(c, c.CurrentVersion())
					if c.IsPinned() {
						t.AddField(version, tableprinter.WithColor(cs.Cyan))
					} else {
						t.AddField(version)
					}

					t.EndRow()
				}
				return t.Render()
			},
		},
		func() *cobra.Command {
			var forceFlag bool
			var pinFlag string
			cmd := &cobra.Command{
				Use:   "install <repository>",
				Short: "Install a gh extension from a repository",
				Long: heredoc.Docf(`
					Install a GitHub CLI extension from a GitHub or local repository.

					For GitHub repositories, the repository argument can be specified in
					%[1]sOWNER/REPO%[1]s format or as a full repository URL.
					The URL format is useful when the repository is not hosted on %[1]sgithub.com%[1]s.

					For remote repositories, the GitHub CLI first looks for the release artifacts assuming
					that it's a binary extension i.e. prebuilt binaries provided as part of the release.
					In the absence of a release, the repository itself is cloned assuming that it's a
					script extension i.e. prebuilt executable or script exists on its root.

					The %[1]s--pin%[1]s flag may be used to specify a tag or commit for binary and script
					extensions respectively, the latest version is used otherwise.

					For local repositories, often used while developing extensions, use %[1]s.%[1]s as the
					value of the repository argument. Note the following:

					- After installing an extension from a locally cloned repository, the GitHub CLI will
					manage this extension as a symbolic link (or equivalent mechanism on Windows) pointing
					to an executable file with the same name as the repository in the repository's root.
					For example, if the repository is named %[1]sgh-foobar%[1]s, the symbolic link will point
					to %[1]sgh-foobar%[1]s in the extension repository's root.
					- When executing the extension, the GitHub CLI will run the executable file found
					by following the symbolic link. If no executable file is found, the extension
					will fail to execute.
					- If the extension is precompiled, the executable file must be built manually and placed
					in the repository's root.

					For the list of available extensions, see <https://github.com/topics/gh-extension>.
				`, "`"),
				Example: heredoc.Doc(`
					# Install an extension from a remote repository hosted on GitHub
					$ gh extension install owner/gh-extension

					# Install an extension from a remote repository via full URL
					$ gh extension install https://my.ghes.com/owner/gh-extension

					# Install an extension from a local repository in the current working directory
					$ gh extension install .
				`),
				Args: cmdutil.MinimumArgs(1, "must specify a repository to install from"),
				RunE: func(cmd *cobra.Command, args []string) error {
					if args[0] == "." {
						if pinFlag != "" {
							return fmt.Errorf("local extensions cannot be pinned")
						}
						wd, err := os.Getwd()
						if err != nil {
							return err
						}
						_, err = checkValidExtension(cmd.Root(), m, filepath.Base(wd), "")
						if err != nil {
							return err
						}

						err = m.InstallLocal(wd)
						var ErrExtensionExecutableNotFound *ErrExtensionExecutableNotFound
						if errors.As(err, &ErrExtensionExecutableNotFound) {
							cs := io.ColorScheme()
							if io.IsStdoutTTY() {
								fmt.Fprintf(io.ErrOut, "%s %s", cs.WarningIcon(), ErrExtensionExecutableNotFound.Error())
							}
							return nil
						}
						return err
					}

					repo, err := ghrepo.FromFullName(args[0])
					if err != nil {
						return err
					}

					cs := io.ColorScheme()

					if ext, err := checkValidExtension(cmd.Root(), m, repo.RepoName(), repo.RepoOwner()); err != nil {
						// If an existing extension was found and --force was specified, attempt to upgrade.
						if forceFlag && ext != nil {
							return upgradeFunc(ext.Name(), forceFlag)
						}

						if errors.Is(err, alreadyInstalledError) {
							fmt.Fprintf(io.ErrOut, "%s Extension %s is already installed\n", cs.WarningIcon(), ghrepo.FullName(repo))
							return nil
						}

						return err
					}

					io.StartProgressIndicator()
					err = m.Install(repo, pinFlag)
					io.StopProgressIndicator()

					if err != nil {
						if errors.Is(err, releaseNotFoundErr) {
							return fmt.Errorf("%s Could not find a release of %s for %s",
								cs.FailureIcon(), args[0], cs.Cyan(pinFlag))
						} else if errors.Is(err, commitNotFoundErr) {
							return fmt.Errorf("%s %s does not exist in %s",
								cs.FailureIcon(), cs.Cyan(pinFlag), args[0])
						} else if errors.Is(err, repositoryNotFoundErr) {
							return fmt.Errorf("%s Could not find extension '%s' on host %s",
								cs.FailureIcon(), args[0], repo.RepoHost())
						}
						return err
					}

					if io.IsStdoutTTY() {
						fmt.Fprintf(io.Out, "%s Installed extension %s\n", cs.SuccessIcon(), args[0])
						if pinFlag != "" {
							fmt.Fprintf(io.Out, "%s Pinned extension at %s\n", cs.SuccessIcon(), cs.Cyan(pinFlag))
						}
					}
					return nil
				},
			}
			cmd.Flags().BoolVar(&forceFlag, "force", false, "Force upgrade extension, or ignore if latest already installed")
			cmd.Flags().StringVar(&pinFlag, "pin", "", "Pin extension to a release tag or commit ref")
			cmdutil.DisableAuthCheck(cmd)
			return cmd
		}(),
		func() *cobra.Command {
			var flagAll bool
			var flagForce bool
			var flagDryRun bool
			cmd := &cobra.Command{
				Use:   "upgrade {<name> | --all}",
				Short: "Upgrade installed extensions",
				Args: func(cmd *cobra.Command, args []string) error {
					if len(args) == 0 && !flagAll {
						return cmdutil.FlagErrorf("specify an extension to upgrade or `--all`")
					}
					if len(args) > 0 && flagAll {
						return cmdutil.FlagErrorf("cannot use `--all` with extension name")
					}
					if len(args) > 1 {
						return cmdutil.FlagErrorf("too many arguments")
					}
					return nil
				},
				RunE: func(cmd *cobra.Command, args []string) error {
					var name string
					if len(args) > 0 {
						name = normalizeExtensionSelector(args[0])
					}
					if flagDryRun {
						m.EnableDryRunMode()
					}
					return upgradeFunc(name, flagForce)
				},
			}
			cmd.Flags().BoolVar(&flagAll, "all", false, "Upgrade all extensions")
			cmd.Flags().BoolVar(&flagForce, "force", false, "Force upgrade extension")
			cmd.Flags().BoolVar(&flagDryRun, "dry-run", false, "Only display upgrades")
			return cmd
		}(),
		&cobra.Command{
			Use:   "remove <name>",
			Short: "Remove an installed extension",
			Args:  cobra.ExactArgs(1),
			RunE: func(cmd *cobra.Command, args []string) error {
				extName := normalizeExtensionSelector(args[0])
				if err := m.Remove(extName); err != nil {
					return err
				}
				if io.IsStdoutTTY() {
					cs := io.ColorScheme()
					fmt.Fprintf(io.Out, "%s Removed extension %s\n", cs.SuccessIcon(), extName)
				}
				return nil
			},
		},
		func() *cobra.Command {
			var debug bool
			var singleColumn bool
			cmd := &cobra.Command{
				Use:   "browse",
				Short: "Enter a UI for browsing, adding, and removing extensions",
				Long: heredoc.Docf(`
					This command will take over your terminal and run a fully interactive
					interface for browsing, adding, and removing gh extensions. A terminal
					width greater than 100 columns is recommended.

					To learn how to control this interface, press %[1]s?%[1]s after running to see
					the help text.

					Press %[1]sq%[1]s to quit.

					Running this command with %[1]s--single-column%[1]s should make this command
					more intelligible for users who rely on assistive technology like screen
					readers or high zoom.

					For a more traditional way to discover extensions, see:

						gh ext search

					along with %[1]sgh ext install%[1]s, %[1]sgh ext remove%[1]s, and %[1]sgh repo view%[1]s.
				`, "`"),
				Args: cobra.NoArgs,
				RunE: func(cmd *cobra.Command, args []string) error {
					if !io.CanPrompt() {
						return errors.New("this command runs an interactive UI and needs to be run in a terminal")
					}
					cfg, err := config()
					if err != nil {
						return err
					}
					host, _ := cfg.Authentication().DefaultHost()
					client, err := f.HttpClient()
					if err != nil {
						return err
					}

					detector := featuredetection.NewDetector(client, host)
					searcher := search.NewSearcher(api.NewCachedHTTPClient(client, time.Hour*24), host, detector)

					gc.Stderr = gio.Discard

					opts := browse.ExtBrowseOpts{
						Cmd:          cmd,
						IO:           io,
						Browser:      browser,
						Searcher:     searcher,
						Em:           m,
						Client:       client,
						Cfg:          cfg,
						Debug:        debug,
						SingleColumn: singleColumn,
					}

					return browse.ExtBrowse(opts)
				},
			}
			cmd.Flags().BoolVar(&debug, "debug", false, "Log to /tmp/extBrowse-*")
			cmd.Flags().BoolVarP(&singleColumn, "single-column", "s", false, "Render TUI with only one column of text")
			return cmd
		}(),
		&cobra.Command{
			Use:   "exec <name> [args]",
			Short: "Execute an installed extension",
			Long: heredoc.Docf(`
				Execute an extension using the short name. For example, if the extension repository is
				%[1]sowner/gh-extension%[1]s, you should pass %[1]sextension%[1]s. You can use this command when
				the short name conflicts with a core gh command.

				All arguments after the extension name will be forwarded to the executable
				of the extension.
			`, "`"),
			Example: heredoc.Doc(`
				# Execute a label extension instead of the core gh label command
				$ gh extension exec label
			`),
			Args:               cobra.MinimumNArgs(1),
			DisableFlagParsing: true,
			RunE: func(cmd *cobra.Command, args []string) error {
				if found, err := m.Dispatch(args, io.In, io.Out, io.ErrOut); !found {
					return fmt.Errorf("extension %q not found", args[0])
				} else {
					return err
				}
			},
		},
		func() *cobra.Command {
			promptCreate := func() (string, extensions.ExtTemplateType, error) {
				extName, err := prompter.Input("Extension name:", "")
				if err != nil {
					return extName, -1, err
				}
				options := []string{"Script (Bash, Ruby, Python, etc)", "Go", "Other Precompiled (C++, Rust, etc)"}
				extTmplType, err := prompter.Select("What kind of extension?",
					options[0],
					options)
				return extName, extensions.ExtTemplateType(extTmplType), err
			}
			var flagType string
			cmd := &cobra.Command{
				Use:   "create [<name>]",
				Short: "Create a new extension",
				Example: heredoc.Doc(`
					# Use interactively
					$ gh extension create

					# Create a script-based extension
					$ gh extension create foobar

					# Create a Go extension
					$ gh extension create --precompiled=go foobar

					# Create a non-Go precompiled extension
					$ gh extension create --precompiled=other foobar
				`),
				Args: cobra.MaximumNArgs(1),
				RunE: func(cmd *cobra.Command, args []string) error {
					if cmd.Flags().Changed("precompiled") {
						if flagType != "go" && flagType != "other" {
							return cmdutil.FlagErrorf("value for --precompiled must be 'go' or 'other'. Got '%s'", flagType)
						}
					}
					var extName string
					var err error
					tmplType := extensions.GitTemplateType
					if len(args) == 0 {
						if io.IsStdoutTTY() {
							extName, tmplType, err = promptCreate()
							if err != nil {
								return fmt.Errorf("could not prompt: %w", err)
							}
						}
					} else {
						extName = args[0]
						if flagType == "go" {
							tmplType = extensions.GoBinTemplateType
						} else if flagType == "other" {
							tmplType = extensions.OtherBinTemplateType
						}
					}

					var fullName string

					if strings.HasPrefix(extName, "gh-") {
						fullName = extName
						extName = extName[3:]
					} else {
						fullName = "gh-" + extName
					}

					cs := io.ColorScheme()

					commitIcon := cs.SuccessIcon()
					if err := m.Create(fullName, tmplType); err != nil {
						if errors.Is(err, ErrInitialCommitFailed) {
							commitIcon = cs.FailureIcon()
						} else {
							return err
						}
					}

					if !io.IsStdoutTTY() {
						return nil
					}

					var goBinChecks string

					steps := fmt.Sprintf(
						"- run 'cd %[1]s; gh extension install .; gh %[2]s' to see your new extension in action",
						fullName, extName)

					if tmplType == extensions.GoBinTemplateType {
						goBinChecks = heredoc.Docf(`
						%[1]s Downloaded Go dependencies
						%[1]s Built %[2]s binary
						`, cs.SuccessIcon(), fullName)
						steps = heredoc.Docf(`
						- run 'cd %[1]s; gh extension install .; gh %[2]s' to see your new extension in action
						- run 'go build && gh %[2]s' to see changes in your code as you develop`, fullName, extName)
					} else if tmplType == extensions.OtherBinTemplateType {
						steps = heredoc.Docf(`
						- run 'cd %[1]s; gh extension install .' to install your extension locally
						- fill in script/build.sh with your compilation script for automated builds
						- compile a %[1]s binary locally and run 'gh %[2]s' to see changes`, fullName, extName)
					}
					link := "https://docs.github.com/github-cli/github-cli/creating-github-cli-extensions"
					out := heredoc.Docf(`
						%[1]s Created directory %[2]s
						%[1]s Initialized git repository
						%[7]s Made initial commit
						%[1]s Set up extension scaffolding
						%[6]s
						%[2]s is ready for development!

						%[4]s
						%[5]s
						- run 'gh repo create' to share your extension with others

						For more information on writing extensions:
						%[3]s
					`, cs.SuccessIcon(), fullName, link, cs.Bold("Next Steps"), steps, goBinChecks, commitIcon)
					fmt.Fprint(io.Out, out)
					return nil
				},
			}
			cmd.Flags().StringVar(&flagType, "precompiled", "", "Create a precompiled extension. Possible values: go, other")
			return cmd
		}(),
	)

	return &extCmd
}

func checkValidExtension(rootCmd *cobra.Command, m extensions.ExtensionManager, extName, extOwner string) (extensions.Extension, error) {
	if !strings.HasPrefix(extName, "gh-") {
		return nil, errors.New("extension name must start with `gh-`")
	}

	commandName := strings.TrimPrefix(extName, "gh-")
	if c, _, _ := rootCmd.Find([]string{commandName}); c != rootCmd && c.GroupID != "extension" {
		return nil, fmt.Errorf("%q matches the name of a built-in command or alias", commandName)
	}

	for _, ext := range m.List() {
		if ext.Name() == commandName {
			if extOwner != "" && ext.Owner() == extOwner {
				return ext, alreadyInstalledError
			}
			return ext, fmt.Errorf("there is already an installed extension that provides the %q command", commandName)
		}
	}

	return nil, nil
}

func normalizeExtensionSelector(n string) string {
	if idx := strings.IndexRune(n, '/'); idx >= 0 {
		n = n[idx+1:]
	}
	return strings.TrimPrefix(n, "gh-")
}

func displayExtensionVersion(ext extensions.Extension, version string) string {
	if !ext.IsBinary() && len(version) > 8 {
		return version[:8]
	}
	return version
}
