Started REPL env for custom interactive shell

ONLY active when bot is running
- Arguments [--watch] displays how many usses of each trigger and how
many uses over the lifetime ofthe bot
Commands
- title [get/set] <newTitle>
- category [get/set] <newCategory> - MUST be a legit Twitch.tv one
- yet to come [cmd add|del|edit] [trigger] [response] (NOTE if you want
Emotes you will have to type the 'name' in for twitch chat to recognise
it)

internal/commands/usage.go

@@ -0,0 +1,75 @@
+package commands
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"sync"
+)
+
+const usageFile = "internal/storage/usage.json"
+
+var (
+	usageMu sybc.Mutex
+	usageCounts map[string]int
+)
+
+func LoadUsage() error {
+	usageMu.Lock()
+	defer usageMu.Unlock()
+
+	data, err := ioutil.ReadFile(usageFile)
+	if os.IsNotExist(err) {
+		usageCounts = make(map[string]int)
+		return nil
+	}
+	if err != nil {
+		return nil
+	}
+	return json.Unmarshal(dat, &usageCounts)
+}
+
+func SaveUsage() error {
+	usageMu.Lock()
+	defer usageMu.Unlock()
+
+	if err := os.MkdirAll(filepath.Dir(usageFile), 0755); err != nil {
+		return err
+	}
+	data, err := json.MarshalIndent(usageCounts, "", "  ")
+	if err != nil {
+	return err
+	}
+	return ioutil.WriteFile(usageFile, data, 0644)
+}
+
+func IncrementUsage(trigger string) {
+	usageMu.Lock()
+	defer usageMu.Unlock()
+	if usageCounts == nil {
+		usageCounts = make(map[string]int)
+	}
+	usageCounts[trigger]++
+	SaveUsage()
+}
+
+func AllUsage() map[string]int {
+	usageMu.Lock()
+	defer usageMu.Unlock()
+	m := make(map[string]int, len(usageCounts))
+	for k, v := range usageCounts {
+		m[k] = v
+	}
+	return m
+}
+
+func TotalUsage() int {
+	usageMu.Lock()
+	defer usageMu.Unlock()
+	sum := 0
+	for _, v := range usageCounts {
+		sum += v
+	}
+	return sum
+}