//go:build js && wasm

package main

import (
	"fmt"
	"syscall/js"

	"git.flowmade.one/flowmade-one/iris/reactive"
	"git.flowmade.one/flowmade-one/iris/ui"
)

// Todo represents a single todo item
type Todo struct {
	ID        int
	Text      string
	Completed bool
}

func main() {
	// Signal holding the list of todos
	todos := reactive.NewSignal([]Todo{})

	// Signal for the input field
	inputText := reactive.NewSignal("")

	// Counter for generating unique IDs
	nextID := reactive.NewSignal(1)

	// Create the main app view
	view := ui.VerticalGroup(
		// Title
		ui.TextFromString("Todo List").Padding("16px 0"),

		// Input row: text input + add button
		inputRow(&inputText, func() {
			text := inputText.Get()
			if text == "" {
				return
			}

			// Add new todo
			id := nextID.Get()
			nextID.Set(id + 1)

			currentTodos := todos.Get()
			newTodos := append(currentTodos, Todo{
				ID:        id,
				Text:      text,
				Completed: false,
			})
			todos.Set(newTodos)

			// Clear input
			inputText.Set("")
		}),

		// Todo list
		todoList(&todos),

		// Summary text showing completed count
		ui.TextFromFunction(func() string {
			allTodos := todos.Get()
			if len(allTodos) == 0 {
				return "No todos yet"
			}

			completed := 0
			for _, t := range allTodos {
				if t.Completed {
					completed++
				}
			}
			return fmt.Sprintf("%d of %d completed", completed, len(allTodos))
		}).Padding("16px 0"),
	).MaxWidth("400px").Padding("24px")

	ui.NewApp(view)

	select {}
}

// inputRow creates the input field and add button
func inputRow(inputText *reactive.Signal[string], onAdd func()) ui.View {
	row := ui.NewView()
	row.Display("flex").Gap("8px").Width("100%")

	// Text input
	input := ui.TextInput(inputText, "What needs to be done?")
	input.Width("100%")

	// Handle Enter key to add todo
	input.Element().OnWithEvent("keypress", func(event js.Value) {
		if event.Get("key").String() == "Enter" {
			onAdd()
		}
	})

	// Add button
	addBtn := ui.Button(onAdd, ui.TextFromString("Add"))
	addBtn.Padding("8px 16px")

	row.Child(input)
	row.Child(addBtn)

	return row
}

// todoList renders the list of todos reactively
func todoList(todos *reactive.Signal[[]Todo]) ui.View {
	container := ui.NewView()
	container.Width("100%")

	// Effect that re-renders the list when todos change
	reactive.NewEffect(func() {
		allTodos := todos.Get()

		// Clear existing children
		container.Element().ClearChildren()

		// Render each todo item
		for _, todo := range allTodos {
			item := todoItem(todo, todos)
			container.Child(item)
		}

		// Show empty state if no todos
		if len(allTodos) == 0 {
			emptyText := ui.TextFromString("Add your first todo above")
			emptyText.Color("#666").Padding("16px 0").TextAlign("center")
			container.Child(emptyText)
		}
	})

	return container
}

// todoItem renders a single todo item with toggle and delete
func todoItem(todo Todo, todos *reactive.Signal[[]Todo]) ui.View {
	row := ui.NewView()
	row.Display("flex").Gap("12px").Padding("8px 0").Width("100%").AlignItems("center")
	row.BorderBottom("1px solid #eee")

	// Completed checkbox using public ui.RawCheckbox
	checkbox := ui.RawCheckbox(todo.Completed, func(isChecked bool) {
		toggleTodo(todos, todo.ID, isChecked)
	})

	// Todo text with strikethrough if completed
	textView := ui.NewView()
	textView.Display("flex").Width("100%")
	text := ui.Span(todo.Text)
	if todo.Completed {
		text.TextDecoration("line-through").Color("#999")
	}
	textView.Child(text)

	// Delete button
	deleteBtn := ui.Button(func() {
		deleteTodo(todos, todo.ID)
	}, ui.TextFromString("X"))
	deleteBtn.Padding("4px 8px")

	row.Child(checkbox)
	row.Child(textView)
	row.Child(deleteBtn)

	return row
}

// toggleTodo updates the completed status of a todo
func toggleTodo(todos *reactive.Signal[[]Todo], id int, completed bool) {
	currentTodos := todos.Get()
	newTodos := make([]Todo, len(currentTodos))
	for i, t := range currentTodos {
		if t.ID == id {
			newTodos[i] = Todo{ID: t.ID, Text: t.Text, Completed: completed}
		} else {
			newTodos[i] = t
		}
	}
	todos.Set(newTodos)
}

// deleteTodo removes a todo from the list
func deleteTodo(todos *reactive.Signal[[]Todo], id int) {
	currentTodos := todos.Get()
	newTodos := make([]Todo, 0, len(currentTodos))
	for _, t := range currentTodos {
		if t.ID != id {
			newTodos = append(newTodos, t)
		}
	}
	todos.Set(newTodos)
}