// URLs implements a breadth-first search webcrawler based on the
// example given in section 8.6 of The Go Programming Language.
package main

import (
	"context"
	"fmt"
	"log"
	"os"

	"github.com/urfave/cli/v3"
)

const shortcodeFilename = "urls.csv"

func main() {
	if os.Getenv("GOEXPERIMENT") != "goroutineleakprofile" {
		log.Fatal("Missing GOEXPERIMENT=goroutineleakprofile environment setting")
	}

	// Setting shorfile helps especially for when we log errors
	// without returning them.
	log.SetFlags(log.LstdFlags | log.Lshortfile)

	cmd := &cli.Command{
		Usage: "A configurable web crawler",
		Commands: []*cli.Command{
			{
				Name:  "get",
				Usage: "Crawl the target",
				MutuallyExclusiveFlags: []cli.MutuallyExclusiveFlags{
					{
						Required: true,
						Flags: [][]cli.Flag{
							{
								&cli.StringFlag{
									Name:  "shortcode",
									Usage: "Specify target using a shortcode",
								},
							},
							{
								&cli.StringFlag{
									Name:  "url",
									Usage: "Specify target using a URL",
								},
							},
						},
					},
				},
				Flags: []cli.Flag{
					&cli.IntFlag{
						Name:    "concurrency",
						Aliases: []string{"c"},
						Usage:   "Allowable number of concurrent URL fetches",

						// Default concurrency setting is 1.
						Value: 1,
					},
					&cli.IntFlag{
						Name:        "maxurls",
						Aliases:     []string{"m"},
						Usage:       "Maximum number of URLs to collect",
						DefaultText: "no limit",
					},
					&cli.IntFlag{
						Name:        "depth",
						Aliases:     []string{"d"},
						Usage:       "Maximum URL depth",
						DefaultText: "no limit",
					},
				},
				Action: run,
			},
			{
				Name:  "shortcode",
				Usage: "Configure shortcodes",
				Action: func(ctx context.Context, cmd *cli.Command) error {
					fmt.Println("shortcode!")
					return nil
				},
			},
		},
	}

	if err := cmd.Run(context.Background(), os.Args); err != nil {
		fmt.Printf("\n%v\n", err)
		os.Exit(1)
	}
}