package config

import (
	"strings"
	"testing"
	"time"
)

func TestLoadFromEnvUsesDefaults(t *testing.T) {
	for _, key := range []string{
		"GO_OMNI_HTTP_ADDR", "GO_OMNI_REQUEST_ID_HEADER", "GO_OMNI_ENABLE_LOGGER",
		"GO_OMNI_TRUSTED_PROXIES",
		"GO_OMNI_TRANSPORT", "GO_OMNI_TLS_CERT_FILE", "GO_OMNI_TLS_KEY_FILE",
		"GO_OMNI_LOG_LEVEL", "GO_OMNI_LOG_FORMAT", "GO_OMNI_LOG_OUTPUT",
		"GO_OMNI_LOG_FILE", "GO_OMNI_SERVICE", "GO_OMNI_ENVIRONMENT",
		"GO_OMNI_LOG_ADD_SOURCE", "GO_OMNI_SHUTDOWN_TIMEOUT",
		"GO_OMNI_SLOW_REQUEST_THRESHOLD",
	} {
		t.Setenv(key, "")
	}

	cfg, err := LoadFromEnv("")
	if err != nil {
		t.Fatal(err)
	}
	if cfg.Address != ":8080" || cfg.Transport != TransportNetHTTP || cfg.TLS != (TLSConfig{}) || cfg.RequestIDHeader != "X-Request-ID" || cfg.ShutdownTimeout != 10*time.Second {
		t.Fatalf("unexpected defaults: %+v", cfg)
	}
	if cfg.EnableLogger || cfg.Log.Level != "info" || cfg.Log.Format != "json" || cfg.Log.Output != "stderr" {
		t.Fatalf("unexpected logger defaults: %+v", cfg.Log)
	}
}

func TestTransportEnvironment(t *testing.T) {
	for _, test := range []struct {
		name, transport, cert, key, errorField string
	}{
		{"default", "", "", "", ""},
		{"native", "native", "", "", ""},
		{"nativeTLS", "native", "server.crt", "server.key", ""},
		{"http2", "http2", "server.crt", "server.key", ""},
		{"unknown", "typo", "", "", "transport"},
		{"certOnly", "nethttp", "server.crt", "", "tls"},
		{"keyOnly", "native", "", "server.key", "tls"},
		{"http2WithoutTLS", "http2", "", "", "tls"},
	} {
		t.Run(test.name, func(t *testing.T) {
			t.Setenv("TRANSPORT_TEST_TRANSPORT", test.transport)
			t.Setenv("TRANSPORT_TEST_TLS_CERT_FILE", test.cert)
			t.Setenv("TRANSPORT_TEST_TLS_KEY_FILE", test.key)
			cfg, err := LoadFromEnv("TRANSPORT_TEST_")
			if test.errorField != "" {
				if err == nil || !strings.Contains(err.Error(), test.errorField) {
					t.Fatalf("unexpected error: %v", err)
				}
				return
			}
			if err != nil {
				t.Fatal(err)
			}
			want := test.transport
			if want == "" {
				want = TransportNetHTTP
			}
			if cfg.Transport != want || cfg.TLS.CertFile != test.cert || cfg.TLS.KeyFile != test.key {
				t.Fatalf("settings: %+v", cfg)
			}
		})
	}
}

func TestLoadFromEnvOverridesSettings(t *testing.T) {
	t.Setenv("GO_OMNI_HTTP_ADDR", "127.0.0.1:9090")
	t.Setenv("GO_OMNI_REQUEST_ID_HEADER", "X-Correlation-ID")
	t.Setenv("GO_OMNI_TRUSTED_PROXIES", "127.0.0.1, 10.0.0.0/8")
	t.Setenv("GO_OMNI_ENABLE_LOGGER", "true")
	t.Setenv("GO_OMNI_LOG_LEVEL", "debug")
	t.Setenv("GO_OMNI_LOG_FORMAT", "text")
	t.Setenv("GO_OMNI_LOG_OUTPUT", "stdout")
	t.Setenv("GO_OMNI_SERVICE", "billing")
	t.Setenv("GO_OMNI_ENVIRONMENT", "test")
	t.Setenv("GO_OMNI_LOG_ADD_SOURCE", "true")
	t.Setenv("GO_OMNI_SHUTDOWN_TIMEOUT", "3s")
	t.Setenv("GO_OMNI_SLOW_REQUEST_THRESHOLD", "500ms")

	cfg, err := LoadFromEnv("")
	if err != nil {
		t.Fatal(err)
	}
	if cfg.Address != "127.0.0.1:9090" || cfg.RequestIDHeader != "X-Correlation-ID" || !cfg.EnableLogger || len(cfg.TrustedProxies) != 2 || cfg.TrustedProxies[1] != "10.0.0.0/8" {
		t.Fatalf("unexpected application settings: %+v", cfg)
	}
	if cfg.ShutdownTimeout != 3*time.Second || cfg.Log.Level != "debug" || cfg.Log.Format != "text" || cfg.Log.Output != "stdout" || cfg.Log.Service != "billing" || cfg.Log.Environment != "test" || !cfg.Log.AddSource {
		t.Fatalf("unexpected logger settings: %+v", cfg.Log)
	}
	if cfg.SlowRequestThreshold != 500*time.Millisecond {
		t.Fatal(cfg.SlowRequestThreshold)
	}
}

func TestLoadFromEnvRejectsInvalidValues(t *testing.T) {
	t.Setenv("GO_OMNI_ENABLE_LOGGER", "sometimes")
	if _, err := LoadFromEnv(""); err == nil || !strings.Contains(err.Error(), "ENABLE_LOGGER") {
		t.Fatalf("expected invalid logger flag error, got %v", err)
	}

	t.Setenv("GO_OMNI_ENABLE_LOGGER", "")
	t.Setenv("GO_OMNI_SHUTDOWN_TIMEOUT", "later")
	if _, err := LoadFromEnv(""); err == nil || !strings.Contains(err.Error(), "SHUTDOWN_TIMEOUT") {
		t.Fatalf("expected invalid timeout error, got %v", err)
	}

	t.Setenv("GO_OMNI_SHUTDOWN_TIMEOUT", "1s")
	t.Setenv("GO_OMNI_TRUSTED_PROXIES", "proxy.example.com")
	if _, err := LoadFromEnv(""); err == nil || !strings.Contains(err.Error(), "trustedProxies") {
		t.Fatalf("expected invalid trusted proxy error, got %v", err)
	}
	t.Setenv("GO_OMNI_TRUSTED_PROXIES", "")
	cfg := Default()
	cfg.Address = ""
	if err := cfg.Validate(); err == nil || !strings.Contains(err.Error(), "address") {
		t.Fatalf("expected invalid address error, got %v", err)
	}
	cfg = Default()
	cfg.RequestIDHeader = " "
	if err := cfg.Validate(); err == nil || !strings.Contains(err.Error(), "requestIdHeader") {
		t.Fatalf("expected invalid request header error, got %v", err)
	}
}

func TestWithConfigAndWithLogConfig(t *testing.T) {
	settings := Default()
	settings.Log.Service = "orders"
	settings.TrustedProxies = []string{"127.0.0.1"}
	cfg := Default()
	WithConfig(settings)(&cfg)
	if cfg.Log.Service != "orders" || len(cfg.TrustedProxies) != 1 {
		t.Fatalf("complete config was not applied: %+v", cfg)
	}
	settings.TrustedProxies[0] = "10.0.0.0/8"
	if cfg.TrustedProxies[0] != "127.0.0.1" {
		t.Fatal("WithConfig should copy trusted proxy settings")
	}

	WithLogConfig(Default().Log)(&cfg)
	if cfg.Log.Service != "" {
		t.Fatalf("log config was not replaced: %+v", cfg.Log)
	}
}

func TestApplyEnvPreservesProjectDefaults(t *testing.T) {
	cfg := Default()
	cfg.Address = "127.0.0.1:8123"
	cfg.Log.RedactKeys = []string{"bankAccount"}
	cfg.TrustedProxies = []string{"127.0.0.1"}
	t.Setenv("OVERLAY_TEST_LOG_LEVEL", "debug")
	got, err := ApplyEnv(cfg, "OVERLAY_TEST_")
	if err != nil {
		t.Fatal(err)
	}
	if got.Address != cfg.Address || got.Log.Level != "debug" {
		t.Fatal(got)
	}
	got.Log.RedactKeys[0] = "changed"
	got.TrustedProxies[0] = "192.0.2.1"
	if cfg.Log.RedactKeys[0] != "bankAccount" || cfg.TrustedProxies[0] != "127.0.0.1" {
		t.Fatal("caller-owned defaults mutated")
	}
}