package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"strings"
)

func handleAliasCommand() {
	if len(os.Args) < 3 {
		fmt.Fprintf(os.Stderr, "%s alias: subcommand missing\n", os.Args[0])
		printAliasUsage()
		os.Exit(1)
	}

	subcmd := strings.ToLower(os.Args[2])
	switch subcmd {
	case "list", "ls", "l":
		cmd := flag.NewFlagSet("alias list", flag.ExitOnError)
		cmd.SetOutput(os.Stdout)
		cfgpath := cmd.String("config", "", "path to configuration")
		server := cmd.String("server", "", "server name to use")
		aname := cmd.String("name", "", "filter list to named alias")
		cmd.Parse(os.Args[3:])

		cfg := LoadConfig(*cfgpath)
		es := cfg.GetClient(*server)

		aliases, err := es.CatAliases().Do(context.Background())
		if err != nil {
			fmt.Fprintf(os.Stderr, "elastic error: %s\n", err.Error())
			os.Exit(1)
		}

		for _, alias := range aliases {
			if *aname != "" {
				if alias.Alias == *aname {
					fmt.Printf("%s\n", alias.Index)
				}
			} else {
				fmt.Printf("%s %s\n", alias.Alias, alias.Index)
			}
		}

	case "add":
		cmd := flag.NewFlagSet("alias add", flag.ExitOnError)
		cmd.SetOutput(os.Stdout)
		cmd.Usage = func() {
			fmt.Printf("Usage: %s alias %s [args] <alias> <index>...\n",
				os.Args[0], subcmd)
			cmd.PrintDefaults()
		}
		cfgpath := cmd.String("config", "", "path to configuration")
		server := cmd.String("server", "", "server name to use")
		cmd.Parse(os.Args[3:])

		if len(cmd.Args()) < 2 {
			fmt.Fprintf(os.Stderr, "alias and index required for alias add\n")
			cmd.Usage()
			os.Exit(1)
		}
		aname := cmd.Arg(0)
		indexes := cmd.Args()[1:]

		cfg := LoadConfig(*cfgpath)
		es := cfg.GetClient(*server)

		alias := es.Alias()
		for _, index := range indexes {
			alias.Add(index, aname)
		}
		_, err := alias.Do(context.Background())
		if err != nil {
			fmt.Fprintf(os.Stderr, "elastic error: %s\n", err.Error())
			os.Exit(1)
		}

	case "del":
		fallthrough
	case "delete":
		cmd := flag.NewFlagSet("alias delete", flag.ExitOnError)
		cmd.SetOutput(os.Stdout)
		cmd.Usage = func() {
			fmt.Printf("Usage: %s alias %s [args] <alias> <index>...\n",
				os.Args[0], subcmd)
			cmd.PrintDefaults()
		}
		cfgpath := cmd.String("config", "", "path to configuration")
		server := cmd.String("server", "", "server name to use")
		cmd.Parse(os.Args[3:])

		if len(cmd.Args()) < 2 {
			fmt.Fprintf(os.Stderr, "alias and index required for alias delete\n")
			cmd.Usage()
			os.Exit(1)
		}

		aname := cmd.Arg(0)
		indexes := cmd.Args()[1:]

		cfg := LoadConfig(*cfgpath)
		es := cfg.GetClient(*server)

		alias := es.Alias()
		for _, index := range indexes {
			alias.Remove(index, aname)
		}
		_, err := alias.Do(context.Background())
		if err != nil {
			fmt.Fprintf(os.Stderr, "elastic error: %s\n", err.Error())
			os.Exit(1)
		}

	case "replace":
		cmd := flag.NewFlagSet("alias replace", flag.ExitOnError)
		cmd.SetOutput(os.Stdout)
		cfgpath := cmd.String("config", "", "path to configuration")
		server := cmd.String("server", "", "server name to use")
		aname := cmd.String("name", "", "(required) name of alias")
		oiname := cmd.String("oldindex", "", "name of the old index")
		niname := cmd.String("newindex", "",
			"(required) name of the new index")
		cmd.Parse(os.Args[3:])

		if *aname == "" {
			fmt.Fprintf(os.Stderr, "name parameter is required for alias replace\n")
			cmd.PrintDefaults()
			os.Exit(1)
		}

		if *niname == "" {
			fmt.Fprintf(os.Stderr,
				"newindex parameter is required for alias replace\n")
			cmd.PrintDefaults()
			os.Exit(1)
		}

		cfg := LoadConfig(*cfgpath)
		es := cfg.GetClient(*server)

		oinames := make([]string, 0, 10)
		if *oiname != "" {
			oinames = append(oinames, *oiname)
		} else {
			aliases, err := es.CatAliases().Do(context.Background())
			if err != nil {
				fmt.Fprintf(os.Stderr, "elastic error: %s\n", err.Error())
				os.Exit(1)
			}

			for _, alias := range aliases {
				if alias.Alias == *aname {
					oinames = append(oinames, alias.Index)
				}
			}
		}

		as := es.Alias()
		for _, idx := range oinames {
			as.Remove(idx, *aname)
		}
		as.Add(*niname, *aname)
		_, err := as.Do(context.Background())
		if err != nil {
			fmt.Fprintf(os.Stderr, "elastic error: %s\n", err.Error())
			os.Exit(1)
		}

	case "--help":
		printAliasUsage()
		os.Exit(0)

	default:
		fmt.Fprintf(os.Stderr, "%s: alias '%s' is not a recognized subcommand\n",
			os.Args[0], os.Args[2])
		printAliasUsage()
		os.Exit(1)
	}
}

func printAliasUsage() {
	fmt.Printf("Usage: %s alias <subcommand> ... \n", os.Args[0])
	fmt.Printf("See '%s alias <subcommand> --help' for information", os.Args[0])
	fmt.Printf(" on a specific command\n")
	fmt.Printf("valid subcommands:\n")
	fmt.Printf("    list      list aliases\n")
	fmt.Printf("    add       add alias\n")
	fmt.Printf("    delete    delete alias\n")
	fmt.Printf("    replace   replace alias (single step add/delete)\n")
}