package luajit

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

func TestNew(t *testing.T) {
	L := New()
	if L == nil {
		t.Fatal("Failed to create Lua state")
	}
	defer L.Close()
}

func TestLoadString(t *testing.T) {
	tests := []struct {
		name    string
		code    string
		wantErr bool
	}{
		{
			name:    "valid function",
			code:    "function add(a, b) return a + b end",
			wantErr: false,
		},
		{
			name:    "valid expression",
			code:    "return 1 + 1",
			wantErr: false,
		},
		{
			name:    "syntax error",
			code:    "function bad syntax",
			wantErr: true,
		},
	}

	for _, tt := range tests {
		L := New()
		if L == nil {
			t.Fatal("Failed to create Lua state")
		}
		defer L.Close()

		err := L.LoadString(tt.code)
		if (err != nil) != tt.wantErr {
			t.Errorf("LoadString() error = %v, wantErr %v", err, tt.wantErr)
			return
		}

		if !tt.wantErr {
			// Verify the function is on the stack
			if L.GetTop() != 1 {
				t.Error("LoadString() did not leave exactly one value on stack")
			}
			if !L.IsFunction(-1) {
				t.Error("LoadString() did not leave a function on the stack")
			}
		}
	}
}

func TestExecuteString(t *testing.T) {
	tests := []struct {
		name          string
		code          string
		wantResults   int
		checkResults  func(*State) error
		wantErr       bool
		wantStackSize int
	}{
		{
			name:        "no results",
			code:        "local x = 1",
			wantResults: 0,
			wantErr:     false,
		},
		{
			name:        "single result",
			code:        "return 42",
			wantResults: 1,
			checkResults: func(L *State) error {
				if n := L.ToNumber(-1); n != 42 {
					return fmt.Errorf("got %v, want 42", n)
				}
				return nil
			},
			wantErr: false,
		},
		{
			name:        "multiple results",
			code:        "return 1, 'test', true",
			wantResults: 3,
			checkResults: func(L *State) error {
				if n := L.ToNumber(-3); n != 1 {
					return fmt.Errorf("first result: got %v, want 1", n)
				}
				if s := L.ToString(-2); s != "test" {
					return fmt.Errorf("second result: got %v, want 'test'", s)
				}
				if b := L.ToBoolean(-1); !b {
					return fmt.Errorf("third result: got %v, want true", b)
				}
				return nil
			},
			wantErr: false,
		},
		{
			name:    "syntax error",
			code:    "this is not valid lua",
			wantErr: true,
		},
		{
			name:    "runtime error",
			code:    "error('test error')",
			wantErr: true,
		},
	}

	for _, tt := range tests {
		L := New()
		if L == nil {
			t.Fatal("Failed to create Lua state")
		}
		defer L.Close()

		// Record initial stack size
		initialStack := L.GetTop()

		results, err := L.ExecuteString(tt.code)
		if (err != nil) != tt.wantErr {
			t.Errorf("ExecuteString() error = %v, wantErr %v", err, tt.wantErr)
			return
		}

		if err == nil {
			if results != tt.wantResults {
				t.Errorf("ExecuteString() returned %d results, want %d", results, tt.wantResults)
			}

			if tt.checkResults != nil {
				if err := tt.checkResults(L); err != nil {
					t.Errorf("Result check failed: %v", err)
				}
			}

			// Verify stack size matches expected results
			if got := L.GetTop() - initialStack; got != tt.wantResults {
				t.Errorf("Stack size grew by %d, want %d", got, tt.wantResults)
			}
		}
	}
}

func TestDoString(t *testing.T) {
	tests := []struct {
		name    string
		code    string
		wantErr bool
	}{
		{"simple addition", "return 1 + 1", false},
		{"set global", "test = 42", false},
		{"syntax error", "this is not valid lua", true},
		{"runtime error", "error('test error')", true},
	}

	for _, tt := range tests {
		L := New()
		if L == nil {
			t.Fatal("Failed to create Lua state")
		}
		defer L.Close()

		initialStack := L.GetTop()
		err := L.DoString(tt.code)
		if (err != nil) != tt.wantErr {
			t.Errorf("DoString() error = %v, wantErr %v", err, tt.wantErr)
		}

		// Verify stack is unchanged
		if finalStack := L.GetTop(); finalStack != initialStack {
			t.Errorf("Stack size changed from %d to %d", initialStack, finalStack)
		}
	}
}

func TestPushAndGetValues(t *testing.T) {
	values := []struct {
		name  string
		push  func(*State)
		check func(*State) error
	}{
		{
			name: "string",
			push: func(L *State) { L.PushString("hello") },
			check: func(L *State) error {
				if got := L.ToString(-1); got != "hello" {
					return fmt.Errorf("got %q, want %q", got, "hello")
				}
				return nil
			},
		},
		{
			name: "number",
			push: func(L *State) { L.PushNumber(42.5) },
			check: func(L *State) error {
				if got := L.ToNumber(-1); got != 42.5 {
					return fmt.Errorf("got %f, want %f", got, 42.5)
				}
				return nil
			},
		},
		{
			name: "boolean",
			push: func(L *State) { L.PushBoolean(true) },
			check: func(L *State) error {
				if got := L.ToBoolean(-1); !got {
					return fmt.Errorf("got %v, want true", got)
				}
				return nil
			},
		},
		{
			name: "nil",
			push: func(L *State) { L.PushNil() },
			check: func(L *State) error {
				if typ := L.GetType(-1); typ != TypeNil {
					return fmt.Errorf("got type %v, want TypeNil", typ)
				}
				return nil
			},
		},
	}

	for _, v := range values {
		L := New()
		if L == nil {
			t.Fatal("Failed to create Lua state")
		}
		defer L.Close()

		v.push(L)
		if err := v.check(L); err != nil {
			t.Error(err)
		}
	}
}

func TestStackManipulation(t *testing.T) {
	L := New()
	if L == nil {
		t.Fatal("Failed to create Lua state")
	}
	defer L.Close()

	// Push values
	values := []string{"first", "second", "third"}
	for _, v := range values {
		L.PushString(v)
	}

	// Check size
	if top := L.GetTop(); top != len(values) {
		t.Errorf("stack size = %d, want %d", top, len(values))
	}

	// Pop one value
	L.Pop(1)

	// Check new top
	if str := L.ToString(-1); str != "second" {
		t.Errorf("top value = %q, want 'second'", str)
	}

	// Check new size
	if top := L.GetTop(); top != len(values)-1 {
		t.Errorf("stack size after pop = %d, want %d", top, len(values)-1)
	}
}

func TestGlobals(t *testing.T) {
	L := New()
	if L == nil {
		t.Fatal("Failed to create Lua state")
	}
	defer L.Close()

	// Test via Lua
	if err := L.DoString(`globalVar = "test"`); err != nil {
		t.Fatalf("DoString error: %v", err)
	}

	// Get the global
	L.GetGlobal("globalVar")
	if str := L.ToString(-1); str != "test" {
		t.Errorf("global value = %q, want 'test'", str)
	}
	L.Pop(1)

	// Set and get via API
	L.PushNumber(42)
	L.SetGlobal("testNum")

	L.GetGlobal("testNum")
	if num := L.ToNumber(-1); num != 42 {
		t.Errorf("global number = %f, want 42", num)
	}
}

func TestCall(t *testing.T) {
	tests := []struct {
		funcName   string // Add explicit function name field
		setup      string
		args       []interface{}
		nresults   int
		checkStack func(*State) error
		wantErr    bool
	}{
		{
			funcName: "add",
			setup:    "function add(a, b) return a + b end",
			args:     []interface{}{float64(40), float64(2)},
			nresults: 1,
			checkStack: func(L *State) error {
				if n := L.ToNumber(-1); n != 42 {
					return fmt.Errorf("got %v, want 42", n)
				}
				return nil
			},
		},
		{
			funcName: "multi",
			setup:    "function multi() return 1, 'test', true end",
			args:     []interface{}{},
			nresults: 3,
			checkStack: func(L *State) error {
				if n := L.ToNumber(-3); n != 1 {
					return fmt.Errorf("first result: got %v, want 1", n)
				}
				if s := L.ToString(-2); s != "test" {
					return fmt.Errorf("second result: got %v, want 'test'", s)
				}
				if b := L.ToBoolean(-1); !b {
					return fmt.Errorf("third result: got %v, want true", b)
				}
				return nil
			},
		},
		{
			funcName: "err",
			setup:    "function err() error('test error') end",
			args:     []interface{}{},
			nresults: 0,
			wantErr:  true,
		},
	}

	for _, tt := range tests {
		L := New()
		if L == nil {
			t.Fatal("Failed to create Lua state")
		}
		defer L.Close()

		// Setup function
		if err := L.DoString(tt.setup); err != nil {
			t.Fatalf("Setup failed: %v", err)
		}

		// Get function
		L.GetGlobal(tt.funcName)
		if !L.IsFunction(-1) {
			t.Fatal("Failed to get function")
		}

		// Push arguments
		for _, arg := range tt.args {
			if err := L.PushValue(arg); err != nil {
				t.Fatalf("Failed to push argument: %v", err)
			}
		}

		// Call function
		err := L.Call(len(tt.args), tt.nresults)
		if (err != nil) != tt.wantErr {
			t.Errorf("Call() error = %v, wantErr %v", err, tt.wantErr)
			return
		}

		if err == nil && tt.checkStack != nil {
			if err := tt.checkStack(L); err != nil {
				t.Errorf("Stack check failed: %v", err)
			}
		}
	}
}

func TestDoFile(t *testing.T) {
	L := New()
	defer L.Close()

	// Create test file
	content := []byte(`
		function add(a, b)
			return a + b
		end
		result = add(40, 2)
	`)

	tmpDir := t.TempDir()
	filename := filepath.Join(tmpDir, "test.lua")
	if err := os.WriteFile(filename, content, 0644); err != nil {
		t.Fatalf("Failed to create test file: %v", err)
	}

	if err := L.DoFile(filename); err != nil {
		t.Fatalf("DoFile failed: %v", err)
	}

	L.GetGlobal("result")
	if result := L.ToNumber(-1); result != 42 {
		t.Errorf("Expected result=42, got %v", result)
	}
}

func TestRequireAndPackagePath(t *testing.T) {
	L := New()
	defer L.Close()

	tmpDir := t.TempDir()

	// Create module file
	moduleContent := []byte(`
		local M = {}
		function M.multiply(a, b)
			return a * b
		end
		return M
	`)

	if err := os.WriteFile(filepath.Join(tmpDir, "mathmod.lua"), moduleContent, 0644); err != nil {
		t.Fatalf("Failed to create module file: %v", err)
	}

	// Add module path and test require
	if err := L.AddPackagePath(filepath.Join(tmpDir, "?.lua")); err != nil {
		t.Fatalf("AddPackagePath failed: %v", err)
	}

	if err := L.DoString(`
		local math = require("mathmod")
		result = math.multiply(6, 7)
	`); err != nil {
		t.Fatalf("Failed to require module: %v", err)
	}

	L.GetGlobal("result")
	if result := L.ToNumber(-1); result != 42 {
		t.Errorf("Expected result=42, got %v", result)
	}
}

func TestSetPackagePath(t *testing.T) {
	L := New()
	defer L.Close()

	customPath := "./custom/?.lua"
	if err := L.SetPackagePath(customPath); err != nil {
		t.Fatalf("SetPackagePath failed: %v", err)
	}

	L.GetGlobal("package")
	L.GetField(-1, "path")
	if path := L.ToString(-1); path != customPath {
		t.Errorf("Expected package.path=%q, got %q", customPath, path)
	}

	// Test that the old path is completely replaced
	initialPath := L.ToString(-1)
	anotherPath := "./another/?.lua"
	if err := L.SetPackagePath(anotherPath); err != nil {
		t.Fatalf("Second SetPackagePath failed: %v", err)
	}

	L.GetGlobal("package")
	L.GetField(-1, "path")
	if path := L.ToString(-1); path != anotherPath {
		t.Errorf("Expected package.path=%q, got %q", anotherPath, path)
	}
	if path := L.ToString(-1); path == initialPath {
		t.Error("SetPackagePath did not replace the old path")
	}
}

func TestStackDebug(t *testing.T) {
	L := New()
	if L == nil {
		t.Fatal("Failed to create Lua state")
	}
	defer L.Close()

	t.Log("Testing LoadString:")
	initialTop := L.GetTop()
	t.Logf("Initial stack size: %d", initialTop)

	err := L.LoadString("return 42")
	if err != nil {
		t.Errorf("LoadString failed: %v", err)
	}

	afterLoad := L.GetTop()
	t.Logf("Stack size after load: %d", afterLoad)
	t.Logf("Type of top element: %s", L.GetType(-1))

	if L.IsFunction(-1) {
		t.Log("Top element is a function")
	} else {
		t.Log("Top element is NOT a function")
	}

	// Clean up after LoadString test
	L.SetTop(0)

	t.Log("\nTesting ExecuteString:")
	if err := L.DoString("function test() return 1, 'hello', true end"); err != nil {
		t.Errorf("DoString failed: %v", err)
	}

	beforeExec := L.GetTop()
	t.Logf("Stack size before execute: %d", beforeExec)

	nresults, err := L.ExecuteString("return test()")
	if err != nil {
		t.Errorf("ExecuteString failed: %v", err)
	}

	afterExec := L.GetTop()
	t.Logf("Stack size after execute: %d", afterExec)
	t.Logf("Reported number of results: %d", nresults)

	// Print each stack element
	for i := 1; i <= afterExec; i++ {
		t.Logf("Stack[-%d] type: %s", i, L.GetType(-i))
	}

	if afterExec != nresults {
		t.Errorf("Stack size (%d) doesn't match number of results (%d)", afterExec, nresults)
	}
}

func TestTemplateRendering(t *testing.T) {
	L := New()
	if L == nil {
		t.Fatal("Failed to create Lua state")
	}
	defer L.Close()
	defer L.Cleanup()

	// Create a simple render.template function
	renderFunc := func(s *State) int {
		// Template will be at index 1, data at index 2
		data, err := s.ToTable(2)
		if err != nil {
			s.PushString(fmt.Sprintf("failed to get data table: %v", err))
			return -1
		}

		// Push data back as global for template access
		if err := s.PushTable(data); err != nil {
			s.PushString(fmt.Sprintf("failed to push data table: %v", err))
			return -1
		}
		s.SetGlobal("data")

		// Template processing code
		luaCode := `
            local result = {}
            if data.user.logged_in then
                table.insert(result, '<div class="profile">')
                table.insert(result, string.format('    <h1>Welcome, %s!</h1>', tostring(data.user.name)))
                table.insert(result, '    <div class="user-info">')
                table.insert(result, string.format('        <p>Email: %s</p>', tostring(data.user.email)))
                table.insert(result, string.format('        <p>Member since: %s</p>', tostring(data.user.joined_date)))
                table.insert(result, '    </div>')
                if data.user.is_admin then
                    table.insert(result, '    <div class="admin-panel">')
                    table.insert(result, '        <h2>Admin Controls</h2>')
                    table.insert(result, '        <!-- admin content -->')
                    table.insert(result, '    </div>')
                end
                table.insert(result, '</div>')
            else
                table.insert(result, '<div class="profile">')
                table.insert(result, '    <h1>Please log in to view your profile</h1>')
                table.insert(result, '</div>')
            end
            return table.concat(result, '\n')`

		result, err := s.DoStringResult(luaCode)
		if err != nil {
			s.PushString(fmt.Sprintf("template execution failed: %v", err))
			return -1
		}

		// Push the string result
		if str, ok := result.(string); ok {
			s.PushString(str)
			return 1
		}

		s.PushString(fmt.Sprintf("expected string result, got %T", result))
		return -1
	}

	// Create render table and add template function
	L.NewTable()
	if err := L.PushGoFunction(renderFunc); err != nil {
		t.Fatalf("Failed to create render function: %v", err)
	}
	L.SetField(-2, "template")
	L.SetGlobal("render")

	// Test with logged in admin user
	testCode := `
        local data = {
            user = {
                logged_in = true,
                name = "John Doe",
                email = "john@example.com",
                joined_date = "2024-02-09",
                is_admin = true
            }
        }
        return render.template("test.html", data)
    `

	result, err := L.DoStringResult(testCode)
	if err != nil {
		t.Fatalf("Failed to execute test: %v", err)
	}

	str, ok := result.(string)
	if !ok {
		t.Fatalf("Expected string result, got %T", result)
	}

	expectedResult := `<div class="profile">
    <h1>Welcome, John Doe!</h1>
    <div class="user-info">
        <p>Email: john@example.com</p>
        <p>Member since: 2024-02-09</p>
    </div>
    <div class="admin-panel">
        <h2>Admin Controls</h2>
        <!-- admin content -->
    </div>
</div>`

	if str != expectedResult {
		t.Errorf("\nExpected:\n%s\n\nGot:\n%s", expectedResult, str)
	}

	// Test with logged out user
	testCode = `
        local data = {
            user = {
                logged_in = false
            }
        }
        return render.template("test.html", data)
    `

	result, err = L.DoStringResult(testCode)
	if err != nil {
		t.Fatalf("Failed to execute logged out test: %v", err)
	}

	str, ok = result.(string)
	if !ok {
		t.Fatalf("Expected string result, got %T", result)
	}

	expectedResult = `<div class="profile">
    <h1>Please log in to view your profile</h1>
</div>`

	if str != expectedResult {
		t.Errorf("\nExpected:\n%s\n\nGot:\n%s", expectedResult, str)
	}
}