package config_test

import (
	"testing"
	"time"

	"github.com/spf13/viper"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"sneak.berlin/go/dnswatcher/internal/config"
	"sneak.berlin/go/dnswatcher/internal/globals"
	"sneak.berlin/go/dnswatcher/internal/logger"
)

// newTestParams creates config.Params suitable for testing
// without requiring the fx dependency injection framework.
func newTestParams(t *testing.T) config.Params {
	t.Helper()

	g := &globals.Globals{
		Appname: "dnswatcher",
		Version: "test",
	}

	l, err := logger.New(nil, logger.Params{Globals: g})
	require.NoError(t, err, "failed to create logger")

	return config.Params{
		Globals: g,
		Logger:  l,
	}
}

// These tests exercise viper global state and MUST NOT use
// t.Parallel(). Each test resets viper for isolation.

func TestNew_DefaultValues(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com,www.example.com")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)

	assert.Equal(t, 8080, cfg.Port)
	assert.False(t, cfg.Debug)
	assert.Equal(t, "./data", cfg.DataDir)
	assert.Equal(t, time.Hour, cfg.DNSInterval)
	assert.Equal(t, 12*time.Hour, cfg.TLSInterval)
	assert.Equal(t, 7, cfg.TLSExpiryWarning)
	assert.False(t, cfg.MaintenanceMode)
	assert.Empty(t, cfg.SlackWebhook)
	assert.Empty(t, cfg.MattermostWebhook)
	assert.Empty(t, cfg.NtfyTopic)
	assert.Empty(t, cfg.SentryDSN)
	assert.Empty(t, cfg.MetricsUsername)
	assert.Empty(t, cfg.MetricsPassword)
	assert.False(t, cfg.SendTestNotification)
}

func TestNew_EnvironmentOverrides(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com")
	t.Setenv("PORT", "9090")
	t.Setenv("DNSWATCHER_DEBUG", "true")
	t.Setenv("DNSWATCHER_DATA_DIR", "/tmp/test-data")
	t.Setenv("DNSWATCHER_DNS_INTERVAL", "30m")
	t.Setenv("DNSWATCHER_TLS_INTERVAL", "6h")
	t.Setenv("DNSWATCHER_TLS_EXPIRY_WARNING", "14")
	t.Setenv("DNSWATCHER_SLACK_WEBHOOK", "https://hooks.slack.com/t")
	t.Setenv("DNSWATCHER_MATTERMOST_WEBHOOK", "https://mm.test/hooks/t")
	t.Setenv("DNSWATCHER_NTFY_TOPIC", "https://ntfy.sh/test")
	t.Setenv("DNSWATCHER_SENTRY_DSN", "https://sentry.test/1")
	t.Setenv("DNSWATCHER_MAINTENANCE_MODE", "true")
	t.Setenv("DNSWATCHER_METRICS_USERNAME", "admin")
	t.Setenv("DNSWATCHER_METRICS_PASSWORD", "secret")
	t.Setenv("DNSWATCHER_SEND_TEST_NOTIFICATION", "true")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)

	assert.Equal(t, 9090, cfg.Port)
	assert.True(t, cfg.Debug)
	assert.Equal(t, "/tmp/test-data", cfg.DataDir)
	assert.Equal(t, 30*time.Minute, cfg.DNSInterval)
	assert.Equal(t, 6*time.Hour, cfg.TLSInterval)
	assert.Equal(t, 14, cfg.TLSExpiryWarning)
	assert.Equal(t, "https://hooks.slack.com/t", cfg.SlackWebhook)
	assert.Equal(t, "https://mm.test/hooks/t", cfg.MattermostWebhook)
	assert.Equal(t, "https://ntfy.sh/test", cfg.NtfyTopic)
	assert.Equal(t, "https://sentry.test/1", cfg.SentryDSN)
	assert.True(t, cfg.MaintenanceMode)
	assert.Equal(t, "admin", cfg.MetricsUsername)
	assert.Equal(t, "secret", cfg.MetricsPassword)
	assert.True(t, cfg.SendTestNotification)
}

func TestNew_NoTargetsError(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "")

	_, err := config.New(nil, newTestParams(t))
	require.Error(t, err)
	assert.ErrorIs(t, err, config.ErrNoTargets)
}

func TestNew_OnlyEmptyCSVSegments(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", " , , ")

	_, err := config.New(nil, newTestParams(t))
	require.Error(t, err)
	assert.ErrorIs(t, err, config.ErrNoTargets)
}

func TestNew_InvalidDNSInterval_FallsBackToDefault(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com")
	t.Setenv("DNSWATCHER_DNS_INTERVAL", "banana")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)
	assert.Equal(t, time.Hour, cfg.DNSInterval,
		"invalid DNS interval should fall back to 1h default")
}

func TestNew_InvalidTLSInterval_FallsBackToDefault(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com")
	t.Setenv("DNSWATCHER_TLS_INTERVAL", "notaduration")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)
	assert.Equal(t, 12*time.Hour, cfg.TLSInterval,
		"invalid TLS interval should fall back to 12h default")
}

func TestNew_BothIntervalsInvalid(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com")
	t.Setenv("DNSWATCHER_DNS_INTERVAL", "xyz")
	t.Setenv("DNSWATCHER_TLS_INTERVAL", "abc")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)
	assert.Equal(t, time.Hour, cfg.DNSInterval)
	assert.Equal(t, 12*time.Hour, cfg.TLSInterval)
}

func TestNew_DebugEnablesDebugLogging(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com")
	t.Setenv("DNSWATCHER_DEBUG", "true")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)
	assert.True(t, cfg.Debug)
}

func TestNew_PortEnvNotPrefixed(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com")
	t.Setenv("PORT", "3000")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)
	assert.Equal(t, 3000, cfg.Port,
		"PORT env should work without DNSWATCHER_ prefix")
}

func TestNew_TargetClassification(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS",
		"example.com,www.example.com,api.example.com,example.org")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)

	// example.com and example.org are apex domains
	assert.Len(t, cfg.Domains, 2)
	// www.example.com and api.example.com are hostnames
	assert.Len(t, cfg.Hostnames, 2)
}

func TestNew_InvalidTargetPublicSuffix(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "co.uk")

	_, err := config.New(nil, newTestParams(t))
	require.Error(t, err, "public suffix should be rejected")
}

func TestNew_EmptyAppnameDefaultsToDnswatcher(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com")

	g := &globals.Globals{Appname: "", Version: "test"}

	l, err := logger.New(nil, logger.Params{Globals: g})
	require.NoError(t, err)

	cfg, err := config.New(
		nil, config.Params{Globals: g, Logger: l},
	)
	require.NoError(t, err)
	assert.Equal(t, 8080, cfg.Port,
		"defaults should load when appname is empty")
}

func TestNew_TargetsWithWhitespace(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", " example.com , www.example.com ")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)
	assert.Equal(t, 2, len(cfg.Domains)+len(cfg.Hostnames),
		"whitespace around targets should be trimmed")
}

func TestNew_TargetsWithTrailingComma(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com,www.example.com,")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)
	assert.Equal(t, 2, len(cfg.Domains)+len(cfg.Hostnames),
		"trailing comma should be ignored")
}

func TestNew_CustomDNSIntervalDuration(t *testing.T) {
	viper.Reset()
	t.Setenv("DNSWATCHER_TARGETS", "example.com")
	t.Setenv("DNSWATCHER_DNS_INTERVAL", "5s")

	cfg, err := config.New(nil, newTestParams(t))
	require.NoError(t, err)
	assert.Equal(t, 5*time.Second, cfg.DNSInterval)
}

func TestStatePath(t *testing.T) {
	t.Parallel()

	tests := []struct {
		name    string
		dataDir string
		want    string
	}{
		{"default", "./data", "./data/state.json"},
		{"absolute", "/var/lib/dw", "/var/lib/dw/state.json"},
		{"nested", "/opt/app/data", "/opt/app/data/state.json"},
		{"empty", "", "/state.json"},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			cfg := &config.Config{DataDir: tt.dataDir}
			assert.Equal(t, tt.want, cfg.StatePath())
		})
	}
}