package version

import (
	"runtime"
	"strings"
	"testing"

	"github.com/prometheus/client_golang/prometheus"
	dto "github.com/prometheus/client_model/go"
)

func TestCheckVersion(t *testing.T) {
	tests := []struct {
		In       string
		Min      string
		Expected bool
	}{
		// Basic version comparisons
		{"v3.8.4", "v3.8.5", false},
		{"v3.9.3", "v3.8.5", true},
		{"v3.8.5", "v3.8.5", true},
		// Dev snapshot should always pass
		{"dev-snapshot", "v3.8.5", true},
		{"dev-snapshot", "v99.99.99", true},
		// Versions with Git hashes should be stripped
		{"v3.8.5/abc123", "v3.8.5", true},
		{"v3.8.4/abc123", "v3.8.5", false},
		{"v3.9.0/def456", "v3.8.5", true},
		// Pre-release versions
		{"v3.8.5-alpha", "v3.8.5", false},
		{"v3.8.5", "v3.8.5-alpha", true},
		{"v3.8.5-beta", "v3.8.5-alpha", true},
	}

	for _, d := range tests {
		r := CheckVersion(d.In, d.Min)
		if r != d.Expected {
			t.Errorf("CheckVersion(%q, %q) = %t, expected %t", d.In, d.Min, r, d.Expected)
		}
	}
}

func TestVersionInfo(t *testing.T) {
	info := VersionInfo()

	// Check that we get a valid Info struct
	if info.Version == "" {
		t.Error("VersionInfo().Version should not be empty")
	}

	// Version should start with "v" or be "dev-snapshot"
	if !strings.HasPrefix(info.Version, "v") && info.Version != "dev-snapshot" {
		t.Errorf("Version should start with 'v' or be 'dev-snapshot', got: %s", info.Version)
	}

	// GitRevShort should be <= 7 characters if set
	if info.GitRevShort != "" && len(info.GitRevShort) > 7 {
		t.Errorf("GitRevShort should be <= 7 characters, got: %s", info.GitRevShort)
	}

	// GitRevShort should be prefix of GitRev if both are set
	if info.GitRev != "" && info.GitRevShort != "" {
		if !strings.HasPrefix(info.GitRev, info.GitRevShort) {
			t.Errorf("GitRevShort should be prefix of GitRev: %s not prefix of %s",
				info.GitRevShort, info.GitRev)
		}
	}
}

func TestVersion(t *testing.T) {
	version := Version()

	if version == "" {
		t.Error("Version() should not return empty string")
	}

	// Should contain Go version
	if !strings.Contains(version, runtime.Version()) {
		t.Errorf("Version should contain Go version %s, got: %s", runtime.Version(), version)
	}

	// Should contain the VERSION variable (or dev-snapshot)
	info := VersionInfo()
	if !strings.Contains(version, info.Version) {
		t.Errorf("Version should contain %s, got: %s", info.Version, version)
	}

	// Should be in expected format: "version (extras)"
	if !strings.Contains(version, "(") || !strings.Contains(version, ")") {
		t.Errorf("Version should be in format 'version (extras)', got: %s", version)
	}
}

func TestVersionCmd(t *testing.T) {
	appName := "testapp"
	cmd := VersionCmd(appName)

	// Test basic command properties
	if cmd.Use != "version" {
		t.Errorf("Expected command use to be 'version', got: %s", cmd.Use)
	}

	if cmd.Short == "" {
		t.Error("Command should have a short description")
	}

	if cmd.Long == "" {
		t.Error("Command should have a long description")
	}

	if cmd.Run == nil {
		t.Error("Command should have a Run function")
	}

	// Test that the command can be executed without error
	cmd.SetArgs([]string{})
	err := cmd.Execute()
	if err != nil {
		t.Errorf("VersionCmd execution should not return error, got: %s", err)
	}
}

func TestKongVersionCmd(t *testing.T) {
	cmd := &KongVersionCmd{Name: "testapp"}

	// Test that Run() doesn't return an error
	err := cmd.Run()
	if err != nil {
		t.Errorf("KongVersionCmd.Run() should not return error, got: %s", err)
	}
}

func TestRegisterMetric(t *testing.T) {
	// Create a test registry
	registry := prometheus.NewRegistry()

	// Test registering metric without name
	RegisterMetric("", registry)

	// Gather metrics
	metricFamilies, err := registry.Gather()
	if err != nil {
		t.Fatalf("Failed to gather metrics: %s", err)
	}

	// Find the build_info metric
	var buildInfoFamily *dto.MetricFamily
	for _, family := range metricFamilies {
		if family.GetName() == "build_info" {
			buildInfoFamily = family
			break
		}
	}

	if buildInfoFamily == nil {
		t.Fatal("build_info metric not found")
	}

	if buildInfoFamily.GetHelp() == "" {
		t.Error("build_info metric should have help text")
	}

	metrics := buildInfoFamily.GetMetric()
	if len(metrics) == 0 {
		t.Fatal("build_info metric should have at least one sample")
	}

	// Check that the metric has the expected labels
	metric := metrics[0]
	labels := metric.GetLabel()

	expectedLabels := []string{"version", "buildtime", "gittime", "git"}
	labelMap := make(map[string]string)

	for _, label := range labels {
		labelMap[label.GetName()] = label.GetValue()
	}

	for _, expectedLabel := range expectedLabels {
		if _, exists := labelMap[expectedLabel]; !exists {
			t.Errorf("Expected label %s not found in metric", expectedLabel)
		}
	}

	// Check that the metric value is 1
	if metric.GetGauge().GetValue() != 1 {
		t.Errorf("Expected build_info metric value to be 1, got %f", metric.GetGauge().GetValue())
	}
}

func TestRegisterMetricWithName(t *testing.T) {
	// Create a test registry
	registry := prometheus.NewRegistry()

	// Test registering metric with custom name
	appName := "my-test-app"
	RegisterMetric(appName, registry)

	// Gather metrics
	metricFamilies, err := registry.Gather()
	if err != nil {
		t.Fatalf("Failed to gather metrics: %s", err)
	}

	// Find the my_test_app_build_info metric
	expectedName := "my_test_app_build_info"
	var buildInfoFamily *dto.MetricFamily
	for _, family := range metricFamilies {
		if family.GetName() == expectedName {
			buildInfoFamily = family
			break
		}
	}

	if buildInfoFamily == nil {
		t.Fatalf("%s metric not found", expectedName)
	}
}

func TestVersionConsistency(t *testing.T) {
	// Call Version() multiple times and ensure it returns the same result
	v1 := Version()
	v2 := Version()

	if v1 != v2 {
		t.Errorf("Version() should return consistent results: %s != %s", v1, v2)
	}
}

func TestVersionInfoConsistency(t *testing.T) {
	// Ensure VersionInfo() is consistent with Version()
	info := VersionInfo()
	version := Version()

	// Version string should contain the semantic version
	if !strings.Contains(version, info.Version) {
		t.Errorf("Version() should contain VersionInfo().Version: %s not in %s",
			info.Version, version)
	}

	// If GitRevShort is set, version should contain it
	if info.GitRevShort != "" {
		if !strings.Contains(version, info.GitRevShort) {
			t.Errorf("Version() should contain GitRevShort: %s not in %s",
				info.GitRevShort, version)
		}
	}
}

// Test edge cases
func TestCheckVersionEdgeCases(t *testing.T) {
	// Test with empty strings
	if CheckVersion("", "v1.0.0") {
		t.Error("Empty version should not be >= v1.0.0")
	}

	// Test with malformed versions (should be handled gracefully)
	// Note: semver.Compare might panic or return unexpected results for invalid versions
	// but our function should handle the common cases
	tests := []struct {
		version string
		minimum string
		desc    string
	}{
		{"v1.0.0/", "v1.0.0", "version with trailing slash"},
		{"v1.0.0/abc/def", "v1.0.0", "version with multiple slashes"},
	}

	for _, test := range tests {
		// This should not panic
		result := CheckVersion(test.version, test.minimum)
		t.Logf("%s: CheckVersion(%q, %q) = %t", test.desc, test.version, test.minimum, result)
	}
}

// Benchmark version operations
func BenchmarkVersion(b *testing.B) {
	// Reset the cached version to test actual computation
	v = ""

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		_ = Version()
	}
}

func BenchmarkVersionInfo(b *testing.B) {
	for i := 0; i < b.N; i++ {
		_ = VersionInfo()
	}
}

func BenchmarkCheckVersion(b *testing.B) {
	version := "v1.2.3/abc123"
	minimum := "v1.2.0"

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		_ = CheckVersion(version, minimum)
	}
}

func BenchmarkCheckVersionDevSnapshot(b *testing.B) {
	version := "dev-snapshot"
	minimum := "v1.2.0"

	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		_ = CheckVersion(version, minimum)
	}
}