refact round 3

content/data.message.go

@@ -0,0 +1,66 @@
+package content
+
+import (
+	"encoding/csv"
+	"os"
+	"sync"
+)
+
+type message struct {
+	Timestamp string
+	User      string
+	Text      string
+}
+
+// MessageBoard holds message board data
+type MessageBoard struct {
+	messages []message
+	mu       sync.Mutex
+	path     string
+}
+
+// NewMessageBoard loads messages from the given .dat file
+func NewMessageBoard(path string) *MessageBoard {
+	b := &MessageBoard{path: path}
+	b.load()
+	return b
+}
+
+func (b *MessageBoard) load() {
+	f, err := os.Open(b.path)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	r := csv.NewReader(f)
+	records, err := r.ReadAll()
+	if err != nil {
+		return
+	}
+	for _, row := range records {
+		if len(row) != 3 {
+			continue
+		}
+		b.messages = append(b.messages, message{Timestamp: row[0], User: row[1], Text: row[2]})
+	}
+}
+
+func (b *MessageBoard) append(msg message) error {
+	f, err := os.OpenFile(b.path, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	w := csv.NewWriter(f)
+	err = w.Write([]string{msg.Timestamp, msg.User, msg.Text})
+	w.Flush()
+	return err
+}
+
+func (b *MessageBoard) Count() int {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return len(b.messages)
+}