add: more exercises to funcs

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

@@ -0,0 +1,91 @@
+// For more tutorials: https://blog.learngoprogramming.com
+//
+// Copyright © 2018 Inanc Gumus
+// Learn Go Programming Course
+// License: https://creativecommons.org/licenses/by-nc-sa/4.0/
+//
+
+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
+}