package router

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

func setupTestRoutes(t testing.TB) string {
	t.Helper()

	tempDir := t.TempDir()

	// Create test route files
	routes := map[string]string{
		"index.lua":                     `return "home"`,
		"about.lua":                     `return "about"`,
		"api/users.lua":                 `return "users"`,
		"api/users/get.lua":             `return "get_users"`,
		"api/users/post.lua":            `return "create_user"`,
		"api/users/[id].lua":            `return "user_" .. id`,
		"api/posts/[slug]/comments.lua": `return "comments_" .. slug`,
		"files/*path.lua":               `return "file_" .. path`,
		"middleware.lua":                `-- root middleware`,
		"api/middleware.lua":            `-- api middleware`,
	}

	for path, content := range routes {
		fullPath := filepath.Join(tempDir, path)
		dir := filepath.Dir(fullPath)

		if err := os.MkdirAll(dir, 0755); err != nil {
			t.Fatal(err)
		}

		if err := os.WriteFile(fullPath, []byte(content), 0644); err != nil {
			t.Fatal(err)
		}
	}

	return tempDir
}

func TestRouterBasicFunctionality(t *testing.T) {
	routesDir := setupTestRoutes(t)
	router, err := New(routesDir)
	if err != nil {
		t.Fatal(err)
	}
	defer router.Close()

	tests := []struct {
		method   string
		path     string
		expected bool
		params   map[string]string
	}{
		{"GET", "/", true, nil},
		{"GET", "/about", true, nil},
		{"GET", "/api/users", true, nil},
		{"GET", "/api/users", true, nil},
		{"POST", "/api/users", true, nil},
		{"GET", "/api/users/123", true, map[string]string{"id": "123"}},
		{"GET", "/api/posts/hello-world/comments", true, map[string]string{"slug": "hello-world"}},
		{"GET", "/files/docs/readme.txt", true, map[string]string{"path": "docs/readme.txt"}},
		{"GET", "/nonexistent", false, nil},
		{"DELETE", "/api/users", false, nil},
	}

	for _, tt := range tests {
		t.Run(tt.method+"_"+tt.path, func(t *testing.T) {
			bytecode, params, found := router.Lookup(tt.method, tt.path)

			if found != tt.expected {
				t.Errorf("expected found=%v, got %v", tt.expected, found)
			}

			if tt.expected {
				if bytecode == nil {
					t.Error("expected bytecode, got nil")
				}

				if tt.params != nil {
					for key, expectedValue := range tt.params {
						if actualValue := params.Get(key); actualValue != expectedValue {
							t.Errorf("param %s: expected %s, got %s", key, expectedValue, actualValue)
						}
					}
				}
			}
		})
	}
}

func TestRouterParamsStruct(t *testing.T) {
	params := &Params{
		Keys:   []string{"id", "slug"},
		Values: []string{"123", "hello"},
	}

	if params.Get("id") != "123" {
		t.Errorf("expected '123', got '%s'", params.Get("id"))
	}

	if params.Get("slug") != "hello" {
		t.Errorf("expected 'hello', got '%s'", params.Get("slug"))
	}

	if params.Get("missing") != "" {
		t.Errorf("expected empty string for missing param, got '%s'", params.Get("missing"))
	}
}

func TestRouterMethodNodes(t *testing.T) {
	routesDir := setupTestRoutes(t)
	router, err := New(routesDir)
	if err != nil {
		t.Fatal(err)
	}
	defer router.Close()

	// Test that different methods work independently
	_, _, foundGet := router.Lookup("GET", "/api/users")
	_, _, foundPost := router.Lookup("POST", "/api/users")
	_, _, foundPut := router.Lookup("PUT", "/api/users")

	if !foundGet {
		t.Error("GET /api/users should be found")
	}
	if !foundPost {
		t.Error("POST /api/users should be found")
	}
	if foundPut {
		t.Error("PUT /api/users should not be found")
	}
}

func TestRouterWildcardValidation(t *testing.T) {
	tempDir := t.TempDir()

	// Create invalid wildcard route (not at end)
	invalidPath := filepath.Join(tempDir, "bad/*path/more.lua")
	if err := os.MkdirAll(filepath.Dir(invalidPath), 0755); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(invalidPath, []byte(`return "bad"`), 0644); err != nil {
		t.Fatal(err)
	}

	_, err := New(tempDir)
	if err == nil {
		t.Error("expected error for wildcard not at end")
	}
}

func BenchmarkLookupStatic(b *testing.B) {
	routesDir := setupTestRoutes(b)
	router, err := New(routesDir)
	if err != nil {
		b.Fatal(err)
	}
	defer router.Close()

	method := "GET"
	path := "/api/users"

	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		_, _, _ = router.Lookup(method, path)
	}
}

func BenchmarkLookupDynamic(b *testing.B) {
	routesDir := setupTestRoutes(b)
	router, err := New(routesDir)
	if err != nil {
		b.Fatal(err)
	}
	defer router.Close()

	method := "GET"
	path := "/api/users/12345"

	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		_, _, _ = router.Lookup(method, path)
	}
}

func BenchmarkLookupWildcard(b *testing.B) {
	routesDir := setupTestRoutes(b)
	router, err := New(routesDir)
	if err != nil {
		b.Fatal(err)
	}
	defer router.Close()

	method := "GET"
	path := "/files/docs/deep/nested/file.txt"

	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		_, _, _ = router.Lookup(method, path)
	}
}

func BenchmarkLookupComplex(b *testing.B) {
	routesDir := setupTestRoutes(b)
	router, err := New(routesDir)
	if err != nil {
		b.Fatal(err)
	}
	defer router.Close()

	method := "GET"
	path := "/api/posts/my-blog-post-title/comments"

	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		_, _, _ = router.Lookup(method, path)
	}
}

func BenchmarkLookupNotFound(b *testing.B) {
	routesDir := setupTestRoutes(b)
	router, err := New(routesDir)
	if err != nil {
		b.Fatal(err)
	}
	defer router.Close()

	method := "GET"
	path := "/this/path/does/not/exist"

	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		_, _, _ = router.Lookup(method, path)
	}
}

func BenchmarkLookupMixed(b *testing.B) {
	routesDir := setupTestRoutes(b)
	router, err := New(routesDir)
	if err != nil {
		b.Fatal(err)
	}
	defer router.Close()

	paths := []string{
		"/",
		"/about",
		"/api/users",
		"/api/users/123",
		"/api/posts/hello/comments",
		"/files/document.pdf",
		"/nonexistent",
	}
	method := "GET"

	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		path := paths[i%len(paths)]
		_, _, _ = router.Lookup(method, path)
	}
}

// Comparison benchmarks for string vs byte slice performance
func BenchmarkLookupStringConversion(b *testing.B) {
	routesDir := setupTestRoutes(b)
	router, err := New(routesDir)
	if err != nil {
		b.Fatal(err)
	}
	defer router.Close()

	methodStr := "GET"
	pathStr := "/api/users/12345"

	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		// Direct string usage
		_, _, _ = router.Lookup(methodStr, pathStr)
	}
}

func BenchmarkLookupPreallocated(b *testing.B) {
	routesDir := setupTestRoutes(b)
	router, err := New(routesDir)
	if err != nil {
		b.Fatal(err)
	}
	defer router.Close()

	// Pre-allocated strings (optimal case)
	method := "GET"
	path := "/api/users/12345"

	b.ResetTimer()
	b.ReportAllocs()

	for i := 0; i < b.N; i++ {
		_, _, _ = router.Lookup(method, path)
	}
}