feat: implemented initial login command

internal/config/config.go

@@ -0,0 +1,92 @@
+package config
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path"
+)
+
+const GATOR_CONFIG_FILE = ".gatorconfig.json"
+
+type Config struct {
+	DbUrl           string `json:"db_url"`
+	CurrentUserName string `json:"current_user_name"`
+}
+
+func Read() (*Config, error) {
+	config := Config{}
+
+	configFilePath, err := getConfigPath()
+
+	if err != nil {
+		return nil, err
+	}
+
+	data, err := os.ReadFile(configFilePath)
+
+	if err != nil {
+		return nil, err
+	}
+
+	err = json.Unmarshal(data, &config)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return &config, nil
+}
+
+// TODO: I don't think there should be
+// hidden I/O in this method call
+func (c *Config) SetUser(currentUserName string) error {
+	c.CurrentUserName = currentUserName
+	return writeFile(c)
+}
+
+func (c *Config) String() string {
+	return fmt.Sprintf("Config { DbUrl = %s, CurrentUserName = %s }", c.DbUrl, c.CurrentUserName)
+}
+
+func writeFile(config *Config) error {
+	data, err := json.Marshal(config)
+
+	if err != nil {
+		return err
+	}
+
+	configFilePath, err := getConfigPath()
+
+	if err != nil {
+		return err
+	}
+
+	file, err := os.Create(configFilePath)
+
+	if err != nil {
+		return err
+	}
+
+	defer file.Close()
+
+	_, err = file.Write(data)
+
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func getConfigPath() (string, error) {
+	homeDir, err := os.UserHomeDir()
+
+	if err != nil {
+		return "", err
+	}
+
+	configFilePath := path.Join(homeDir, GATOR_CONFIG_FILE)
+
+	return configFilePath, nil
+}