query

var Command = &cli.Command{
	Name:  "query",
	Usage: "Query a release of specified software",
	Flags: []cli.Flag{
		&cli.StringFlag{
			Name:  "asset",
			Usage: "Output asset URL. `QUERY` can be \"all\" to output all found assets, or specify \"guess\" to guess the most suitable one.",
			Value: "guess",
		},
		&cli.StringFlag{
			Name:  "output",
			Usage: "Output format. `FORMAT` can be \"line\" or \"json\".",
			Value: "line",
		},
		&cli.StringSliceFlag{
			Name:    "assetFilter",
			Aliases: []string{"f"},
			Usage:   "Apply filter to list of asset URLs.",
		},
	},
	Action: func(c *cli.Context) error {
		assetQ := AssetQueryNone
		if c.IsSet("asset") {
			s := c.String("asset")
			switch s {
			case "all":
				assetQ = AssetQueryAll
			case "guess":
				assetQ = AssetQueryGuess
			default:
				return fmt.Errorf("Unknown asset option: %q", s)
			}
		}

		outputType := OutputTypeLine
		if c.IsSet("output") {
			s := c.String("output")
			switch s {
			case "line":
				outputType = OutputTypeLine
			case "json":
				outputType = OutputTypeJson
			default:
				return fmt.Errorf("Unknown output type: %q", s)
			}
		}

		q, err := parser.Parse(c.Args().First())
		if err != nil {
			return err
		}

		fetcher := fetch.Direct{}
		rs, err := q.Execute(c.Context, fetcher)
		if err != nil {
			return err
		}
		if len(rs) == 0 {
			return errors.New("No release matched.")
		}
		r := rs[0]

		filters := c.StringSlice("assetFilter")
		for _, f := range filters {
			r.FilterAssets(f)
		}

		if assetQ == AssetQueryNone && outputType != OutputTypeLine {
			assetQ = AssetQueryGuess
		}
		switch assetQ {
		case AssetQueryNone, AssetQueryAll:
			break
		case AssetQueryGuess:
			r.PickAsset()
			if len(r.AssetURLs) > 0 {
				fmt.Fprintf(os.Stderr, "Too many matches: %v", r.AssetURLs)
			}
		}

		switch outputType {
		case OutputTypeLine:
			if assetQ != AssetQueryNone {
				for _, u := range r.AssetURLs {
					fmt.Printf("%s\n", u)
				}
				return nil
			}
			fmt.Printf("%s\n", r.OriginalName)

		case OutputTypeJson:
			bs, err := json.MarshalIndent(r, "", "\t")
			if err != nil {
				return err
			}

			if _, err := os.Stdout.Write(bs); err != nil {
				return err
			}

		default:
			panic("not reached.")
		}
		return nil
	},
}