package main

import (
	"fmt"
	"strings"
	"testing"
	"time"

	tea "github.com/charmbracelet/bubbletea"
)

func notThis[T comparable](f compareFunc[T]) compareFunc[T] {
	return func(a, b T) bool {
		return !f(a, b)
	}
}

type compareFunc[T comparable] func(T, T) bool

func assertFunc[T comparable](t *testing.T, compare compareFunc[T], actual, expected T, msg string) {
	t.Helper()

	if !compare(actual, expected) {
		t.Errorf("%s: expected %v, got %v", msg, expected, actual)
	}
}

// assertEqual checks if two values are equal and reports an error if they are not.
func assertEqual(t *testing.T, actual, expected interface{}, msg string) {
	t.Helper()

	if actual != expected {
		t.Errorf("%s: expected %v, got %v", msg, expected, actual)
	}
}

// assertNotEqual checks if two values are not equal and reports an error if they are.
func assertNotEqual(t *testing.T, actual, expected interface{}, msg string) {
	t.Helper()

	if actual == expected {
		t.Errorf("%s: expected %v to be different from %v", msg, actual, expected)
	}
}

// keyMsgs converts a series of strings or KeyTypes into a slice of KeyMsgs
func keyMsgs(keys ...interface{}) []tea.KeyMsg {
	keyMessages := []tea.KeyMsg{}

	for _, key := range keys {
		switch keyType := key.(type) {
		case tea.KeyType:
			keyMessages = append(keyMessages, tea.KeyMsg{Type: keyType})
		case string:
			for _, r := range key.(string) {
				keyMessages = append(keyMessages, tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{r}})
			}
		default:
			panic(fmt.Sprintf("Unknown key type: %v", key))
		}
	}

	return keyMessages
}

func sendKeys[T tea.Model](m T, keys ...interface{}) (T, []tea.Cmd) {
	var updatedModel tea.Model

	var cmd tea.Cmd

	var cmds []tea.Cmd

	for _, key := range keyMsgs(keys...) {
		updatedModel, cmd = m.Update(key)
		m = updatedModel.(T)

		if cmd != nil {
			m, cmds, _ = batchCmdUpdate(m, cmd)
		}
	}

	return m, cmds
}

func batchCmdUpdate[T tea.Model](m T, cmd tea.Cmd) (T, []tea.Cmd, error) {
	var updatedModel tea.Model

	var resultCmd tea.Cmd

	var cmds []tea.Cmd

	resultMsg := cmd()

	batchMsg, ok := resultMsg.(tea.BatchMsg)
	if !ok {
		updatedModel, resultCmd = m.Update(resultMsg)
		m = updatedModel.(T)

		cmds = append(cmds, resultCmd)

		return m, cmds, fmt.Errorf("Expected a batch message, got %v", resultMsg)
	}

	// Apply batch messages
	for _, cmd := range batchMsg {
		updatedModel, resultCmd = m.Update(cmd())
		m = updatedModel.(T)

		cmds = append(cmds, resultCmd)
	}

	return m, cmds, nil
}

type mockModel struct {
	messages []tea.Msg
}

func (m mockModel) Init() tea.Cmd {
	return nil
}

func (m mockModel) View() string {
	s := ""

	for _, msg := range m.messages {
		if keyMsg, ok := msg.(tea.KeyMsg); ok {
			if keyMsg.Type == tea.KeyRunes {
				s += string(keyMsg.Runes)
			}
		}
	}

	return s
}

func (m mockModel) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	var cmds []tea.Cmd

	m.messages = append(m.messages, msg)

	if msg, ok := msg.(tea.KeyMsg); ok {
		if msg.Type == tea.KeyEnter {
			cmds = append(cmds, func() tea.Msg { return tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'\n'}} })
		}
	}

	return m, tea.Batch(cmds...)
}

func TestBatchCmdUpdate(t *testing.T) {
	m := mockModel{}

	cmds := []tea.Cmd{
		func() tea.Msg { return tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'a'}} },
		func() tea.Msg { return tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'b'}} },
	}

	m, _, err := batchCmdUpdate(m, tea.Batch(cmds...))
	if err != nil {
		t.Fatalf("Expected no error, got %v", err)
	}

	if len(m.messages) != 2 {
		t.Fatalf("Expected 2 messages, got %v", len(m.messages))
	}

	if m.View() != "ab" {
		t.Fatalf("Expected 'ab', got %s, %+v", m.View(), m)
	}

	m, _, err = batchCmdUpdate(m, func() tea.Msg { return tea.KeyMsg{Type: tea.KeyRunes, Runes: []rune{'c'}} })
	if err == nil {
		t.Fatalf("Expected error, got nil")
	}

	if len(m.messages) != 3 {
		t.Fatalf("Expected 3 messages, got %v", len(m.messages))
	}

	if m.View() != "abc" {
		t.Fatalf("Expected 'abc', got %v", m.View())
	}
}

func TestSendKeys(t *testing.T) {
	m := mockModel{}

	m, _ = sendKeys(m, "ab")

	if len(m.messages) != 2 {
		t.Fatalf("Expected 2 messages, got %v", len(m.messages))
	}

	if m.View() != "ab" {
		t.Fatalf("Expected 'ab', got %s", m.View())
	}

	m, _ = sendKeys(m, "c", tea.KeyEnter)

	// We expect 5 because enter key should create a new message for the newline
	if len(m.messages) != 5 {
		t.Fatalf("Expected 5 messages, got %v", len(m.messages))
	}

	if m.View() != "abc\n" {
		t.Fatalf("Expected 'abc\n', got %s", m.View())
	}
}

// TestParseDuration tests the parseDuration function
func TestParseDuration(t *testing.T) {
	tests := []struct {
		input    string
		expected time.Duration
		hasError bool
	}{
		{"10", 10 * time.Minute, false},
		{"1h", 1 * time.Hour, false},
		{"invalid", 0, true},
	}

	for _, test := range tests {
		result, err := parseDuration(test.input)
		if test.hasError {
			assertNotEqual(t, err, nil, "Expected an error for input "+test.input)
		} else {
			assertEqual(t, err, nil, "Did not expect an error for input "+test.input)
			assertEqual(t, result, test.expected, "Expected duration for input "+test.input)
		}
	}
}

// TestRunCommands tests the runCommands function
func TestRunCommands(t *testing.T) {
	m := newModelBasic(false, "#ffdd57", "#57ddff")
	m.onFocusStart = []string{"echo Focus Start"}

	m.Init()
	m.startCommands(m.onFocusStart)
}

// TestInputView tests the Update method of the model for the input view
func TestInputView(t *testing.T) {
	m := newModel(false, "#ffdd57", "#57ddff", 0, 0, 0, []string{}, []string{}, []string{})

	var err error

	m, _, err = batchCmdUpdate(m, m.Init())
	if err != nil {
		t.Fatalf("Expected batch command after init: %v", err)
	}

	// Verify we're on the input screen
	assertEqual(t, m.currentScreen, INPUT_SCREEN, "Expected currentScreen to be INPUT_SCREEN")
	assertFunc(t, strings.Contains, m.View(), "Break time", "Expected view to contain 'Break time'")

	// Fill the form
	m, _ = sendKeys(m, "10m", tea.KeyEnter, "10m", tea.KeyEnter, "2", tea.KeyEnter)

	// Pass on submit command, doesn't happen because we have multiple layers of batching at the end
	m, _, _ = batchCmdUpdate(m, formSubmit)

	assertEqual(t, m.focusTime, 10*time.Minute, "Expected focus time to be 10 minutes")
	assertEqual(t, m.breakTime, 10*time.Minute, "Expected break time to be 10 minutes")
	assertEqual(t, m.intervals, 2, "Expected rounds to be 2")

	// Pass on start command, doesn't happen because we have multiple layers of batching at the end
	m, _, _ = batchCmdUpdate(m, startTimer)

	assertFunc(t, notThis(strings.Contains), m.View(), "Break time", "Expected view to NOT contain 'Break time'")
	assertEqual(t, m.currentScreen, TIMER_SCREEN, "Expected currentScreen to be TIMER_SCREEN")
}

func TestTimerView(t *testing.T) {
	m := newModel(false, "#ffdd57", "#57ddff", 10*time.Minute, 10*time.Minute, 2, []string{}, []string{}, []string{})

	// Init model with timer values
	m, _, err := batchCmdUpdate(m, m.Init())
	if err != nil {
		t.Fatalf("Expected batch command after init: %v", err)
	}

	// Start timer (batch result from above doesn't apply here)
	m, _, _ = batchCmdUpdate(m, startTimer)

	// Test timer view
	assertEqual(t, m.currentScreen, TIMER_SCREEN, "Expected currentScreen to be timerScreen")
	assertFunc(t, strings.Contains, m.View(), "Focus", "Expected view to contain 'Focus'")
	assertEqual(t, m.state, "Focus", "Expected state to be 'Focus'")

	oneSecCmd := func() tea.Msg { return timeMsg(time.Now().Add(1 * time.Second)) }
	m, _, _ = batchCmdUpdate(m, oneSecCmd)

	assertEqual(t, m.state, "Focus", "Expected state to be 'Focus'")

	// Test switch to break time
	m.startTime = m.startTime.Add(-10 * time.Minute)
	m, _, _ = batchCmdUpdate(m, oneSecCmd)

	assertEqual(t, m.state, "Break", "Expected state to be 'Break'")

	// Switch back to focus time
	m.startTime = m.startTime.Add(-10 * time.Minute)
	m, _, _ = batchCmdUpdate(m, oneSecCmd)

	assertEqual(t, m.state, "Focus", "Expected state to be 'Focus'")
	t.Logf("Incorrect state %+v", m)
}