package nats

import (
	"os"
	"path/filepath"
	"testing"

	"github.com/nats-io/nkeys"
)

func TestConnect_InvalidNKeyFile(t *testing.T) {
	cfg := Config{
		URL:      "nats://localhost:4222",
		NKeyFile: "/nonexistent/file",
		Name:     "test",
	}

	_, err := Connect(cfg)
	if err == nil {
		t.Error("expected error for nonexistent nkey file")
	}
}

func TestConnect_InvalidNKeySeed(t *testing.T) {
	// Create a temp file with invalid content
	tmpDir := t.TempDir()
	keyFile := filepath.Join(tmpDir, "invalid.nkey")
	if err := os.WriteFile(keyFile, []byte("invalid-seed-content"), 0600); err != nil {
		t.Fatalf("failed to write temp file: %v", err)
	}

	cfg := Config{
		URL:      "nats://localhost:4222",
		NKeyFile: keyFile,
		Name:     "test",
	}

	_, err := Connect(cfg)
	if err == nil {
		t.Error("expected error for invalid nkey seed")
	}
}

func TestConnect_ValidSeedParsing(t *testing.T) {
	// Generate a valid NKey seed
	kp, err := nkeys.CreateUser()
	if err != nil {
		t.Fatalf("failed to create nkey: %v", err)
	}

	seed, err := kp.Seed()
	if err != nil {
		t.Fatalf("failed to get seed: %v", err)
	}

	// Write seed to temp file
	tmpDir := t.TempDir()
	keyFile := filepath.Join(tmpDir, "test.nkey")
	if err := os.WriteFile(keyFile, seed, 0600); err != nil {
		t.Fatalf("failed to write temp file: %v", err)
	}

	cfg := Config{
		URL:      "nats://localhost:4222", // Connection will fail, but parsing should work
		NKeyFile: keyFile,
		Name:     "test",
	}

	// Connection will fail since no NATS server is running, but we're testing
	// that the seed parsing works correctly
	_, err = Connect(cfg)
	if err == nil {
		// If it somehow connects (unlikely), that's also fine
		return
	}

	// Error should be about connection, not about nkey parsing
	if err != nil && !contains(err.Error(), "connect") && !contains(err.Error(), "connection") {
		t.Errorf("expected connection error, got: %v", err)
	}
}

func TestConnect_SeedWithWhitespace(t *testing.T) {
	// Generate a valid NKey seed
	kp, err := nkeys.CreateUser()
	if err != nil {
		t.Fatalf("failed to create nkey: %v", err)
	}

	seed, err := kp.Seed()
	if err != nil {
		t.Fatalf("failed to get seed: %v", err)
	}

	// Write seed with trailing newline
	tmpDir := t.TempDir()
	keyFile := filepath.Join(tmpDir, "test.nkey")
	seedWithNewline := append(seed, '\n', ' ', '\t', '\n')
	if err := os.WriteFile(keyFile, seedWithNewline, 0600); err != nil {
		t.Fatalf("failed to write temp file: %v", err)
	}

	cfg := Config{
		URL:      "nats://localhost:4222",
		NKeyFile: keyFile,
		Name:     "test",
	}

	// Should parse the seed correctly despite whitespace
	_, err = Connect(cfg)
	if err != nil && contains(err.Error(), "parse") {
		t.Errorf("seed parsing should handle whitespace: %v", err)
	}
}

func contains(s, substr string) bool {
	return len(s) >= len(substr) && (s == substr || len(s) > 0 && containsHelper(s, substr))
}

func containsHelper(s, substr string) bool {
	for i := 0; i <= len(s)-len(substr); i++ {
		if s[i:i+len(substr)] == substr {
			return true
		}
	}
	return false
}