init

backend/internal/config/config.go

@@ -0,0 +1,76 @@
+package config
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/kelseyhightower/envconfig"
+)
+
+// Config holds all application configuration
+type Config struct {
+	// Database configuration
+	DatabaseURL string `envconfig:"DATABASE_URL" required:"true"`
+
+	// Server configuration
+	Port int `envconfig:"PORT" default:"8080"`
+
+	// Location configuration
+	LocationLat  float64 `envconfig:"LOCATION_LAT" default:"37.7749"`
+	LocationLon  float64 `envconfig:"LOCATION_LON" default:"-122.4194"`
+	LocationName string  `envconfig:"LOCATION_NAME" default:"San Francisco"`
+
+	// Timezone configuration
+	Timezone string `envconfig:"TIMEZONE" default:"America/Los_Angeles"`
+
+	// Weather fetcher configuration
+	FetchInterval time.Duration `envconfig:"FETCH_INTERVAL" default:"15m"`
+
+	// Cache configuration
+	CacheTTL time.Duration `envconfig:"CACHE_TTL" default:"10m"`
+}
+
+// Load reads configuration from environment variables
+func Load() (*Config, error) {
+	var cfg Config
+	if err := envconfig.Process("", &cfg); err != nil {
+		return nil, fmt.Errorf("failed to process environment config: %w", err)
+	}
+
+	// Validate configuration
+	if err := cfg.validate(); err != nil {
+		return nil, fmt.Errorf("invalid configuration: %w", err)
+	}
+
+	return &cfg, nil
+}
+
+// validate checks that configuration values are valid
+func (c *Config) validate() error {
+	if c.Port < 1 || c.Port > 65535 {
+		return fmt.Errorf("port must be between 1 and 65535, got %d", c.Port)
+	}
+
+	if c.LocationLat < -90 || c.LocationLat > 90 {
+		return fmt.Errorf("location latitude must be between -90 and 90, got %f", c.LocationLat)
+	}
+
+	if c.LocationLon < -180 || c.LocationLon > 180 {
+		return fmt.Errorf("location longitude must be between -180 and 180, got %f", c.LocationLon)
+	}
+
+	if c.FetchInterval < time.Minute {
+		return fmt.Errorf("fetch interval must be at least 1 minute, got %s", c.FetchInterval)
+	}
+
+	if c.CacheTTL < time.Second {
+		return fmt.Errorf("cache TTL must be at least 1 second, got %s", c.CacheTTL)
+	}
+
+	return nil
+}
+
+// Addr returns the server address in host:port format
+func (c *Config) Addr() string {
+	return fmt.Sprintf(":%d", c.Port)
+}