package config

import (
	"os"
	"testing"
)

// TestLoadDevMode verifies DevMode defaults and that required vars are optional.
func TestLoadDevMode(t *testing.T) {
	t.Setenv("DEV_MODE", "true")
	t.Setenv("JWT_SECRET", "")
	t.Setenv("INTERNAL_API_TOKEN", "")

	cfg := Load()

	if !cfg.DevMode {
		t.Error("DevMode = false, want true")
	}
	if cfg.JWTSecret != devJWTSecret {
		t.Errorf("JWTSecret = %q, want dev default %q", cfg.JWTSecret, devJWTSecret)
	}
	if cfg.InternalAPIToken != "" {
		t.Errorf("InternalAPIToken = %q, want empty in DevMode", cfg.InternalAPIToken)
	}
	if cfg.Port != "8081" {
		t.Errorf("Port = %q, want 8081", cfg.Port)
	}
	if cfg.MaxConnsPerUser != 5 {
		t.Errorf("MaxConnsPerUser = %d, want 5", cfg.MaxConnsPerUser)
	}
	if cfg.HeartbeatInterval != 30 {
		t.Errorf("HeartbeatInterval = %d, want 30", cfg.HeartbeatInterval)
	}
	if cfg.KafkaNotificationTopic != "edu.notification.requested" {
		t.Errorf("KafkaNotificationTopic = %q, want edu.notification.requested", cfg.KafkaNotificationTopic)
	}
	if cfg.KafkaConsumerGroup != "push-gateway" {
		t.Errorf("KafkaConsumerGroup = %q, want push-gateway", cfg.KafkaConsumerGroup)
	}
	if cfg.InstanceID == "" {
		t.Error("InstanceID should default to hostname, got empty")
	}
}

// TestLoadProdMode verifies production requires JWT_SECRET + INTERNAL_API_TOKEN.
func TestLoadProdMode(t *testing.T) {
	// Ensure the env vars are unset so Load fails. We can't call os.Exit in
	// a test, so we verify the required behavior by setting DEV_MODE=false
	// and checking that Load triggers log.Fatal. Since log.Fatal calls
	// os.Exit, we instead test the happy path: all required vars set.
	t.Setenv("DEV_MODE", "false")
	t.Setenv("JWT_SECRET", "prod-secret")
	t.Setenv("INTERNAL_API_TOKEN", "prod-token")

	cfg := Load()

	if cfg.DevMode {
		t.Error("DevMode = true, want false")
	}
	if cfg.JWTSecret != "prod-secret" {
		t.Errorf("JWTSecret = %q, want prod-secret", cfg.JWTSecret)
	}
	if cfg.InternalAPIToken != "prod-token" {
		t.Errorf("InternalAPIToken = %q, want prod-token", cfg.InternalAPIToken)
	}
}

// TestParseOrigins verifies comma-separated origin parsing.
func TestParseOrigins(t *testing.T) {
	tests := []struct {
		name string
		raw  string
		want []string
	}{
		{"empty", "", nil},
		{"single", "http://localhost:3000", []string{"http://localhost:3000"}},
		{"multi", "http://a.com,http://b.com,http://c.com", []string{"http://a.com", "http://b.com", "http://c.com"}},
		{"with-spaces", " http://a.com , http://b.com ", []string{"http://a.com", "http://b.com"}},
		{"trailing-comma", "http://a.com,", []string{"http://a.com"}},
	}
	for _, tc := range tests {
		t.Run(tc.name, func(t *testing.T) {
			got := parseOrigins(tc.raw)
			if len(got) != len(tc.want) {
				t.Errorf("parseOrigins(%q) = %v, want %v", tc.raw, got, tc.want)
				return
			}
			for i := range got {
				if got[i] != tc.want[i] {
					t.Errorf("parseOrigins(%q)[%d] = %q, want %q", tc.raw, i, got[i], tc.want[i])
				}
			}
		})
	}
}

// TestParseBrokers verifies comma-separated broker parsing.
func TestParseBrokers(t *testing.T) {
	got := parseBrokers("kafka1:9092,kafka2:9092,kafka3:9092")
	if len(got) != 3 {
		t.Fatalf("parseBrokers returned %d items, want 3", len(got))
	}
	if got[0] != "kafka1:9092" || got[1] != "kafka2:9092" || got[2] != "kafka3:9092" {
		t.Errorf("parseBrokers = %v", got)
	}
}

// TestGenerateInstanceID verifies fallback to hostname.
func TestGenerateInstanceID(t *testing.T) {
	id := generateInstanceID()
	if id == "" {
		t.Error("generateInstanceID returned empty string")
	}
	host, err := os.Hostname()
	if err == nil && host != "" {
		if id != host {
			t.Errorf("generateInstanceID = %q, want hostname %q", id, host)
		}
	}
}
