learngo/25-functions/exercises/refactor-to-funcs-3/solution/commands.go

// Copyright © 2018 Inanc Gumus
// Learn Go Programming Course
// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
//
// For more tutorials  : https://learngoprogramming.com
// In-person training  : https://www.linkedin.com/in/inancgumus/
// Follow me on twitter: https://twitter.com/inancgumus

package main

import (
	"encoding/json"
	"fmt"
	"strconv"
	"strings"
)

func runCmd(input string, games []game, byID map[int]game) bool {
	fmt.Println()

	cmd := strings.Fields(input)
	if len(cmd) == 0 {
		return true
	}

	switch cmd[0] {
	case "quit":
		return cmdQuit()

	case "list":
		return cmdList(games)

	case "id":
		return cmdByID(cmd, games, byID)

	case "save":
		return cmdSave(games)
	}
	return true
}

func cmdQuit() bool {
	fmt.Println("bye!")
	return false
}

func cmdList(games []game) bool {
	for _, g := range games {
		printGame(g)
	}
	return true
}

func cmdByID(cmd []string, games []game, byID map[int]game) bool {
	if len(cmd) != 2 {
		fmt.Println("wrong id")
		return true
	}

	id, err := strconv.Atoi(cmd[1])
	if err != nil {
		fmt.Println("wrong id")
		return true
	}

	g, ok := byID[id]
	if !ok {
		fmt.Println("sorry. I don't have the game")
		return true
	}

	printGame(g)

	return true
}

func cmdSave(games []game) bool {
	// load the data into encodable game values
	var jg []jsonGame
	for _, g := range games {
		jg = append(jg, jsonGame{g.id, g.name, g.genre, g.price})
	}

	out, err := json.MarshalIndent(jg, "", "\t")
	if err != nil {
		fmt.Println("sorry, can't save:", err)
		return true
	}

	fmt.Println(string(out))
	return false
}