package main

import (
	"fmt"

	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
)


// Account menu items struct.
var accountMenuItems = []string {
	"order history",
	"faq",
	"about",
}

// Coffee represents a coffee product
type Coffee struct {
	Name        string
	RoastType   string
	Ounces      int
	BeanType    string
	Price       float64
	Color       string // Hex color for background
	Description string
}

// CartItem represents an item in the cart
type CartItem struct {
	Coffee   Coffee
	Quantity int
}

type model struct {
	username       string
	coffees        []Coffee
	cursor         int
	cart           map[int]*CartItem // maps coffee index to cart item
	cartCursor     int               // cursor position in cart view
	accountCursor  int
	accountPage    string
	windowWidth    int
	windowHeight   int
	viewingCart    bool // true when viewing cart details
	viewingAccount bool
}

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

func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		m.windowWidth = msg.Width
		m.windowHeight = msg.Height
		return m, nil

	case tea.KeyMsg:
		switch msg.String() {
		case "ctrl+c", "q":
			return m, tea.Quit

		case "s":
			m.viewingCart = false
			m.viewingAccount = false
			m.accountPage = ""

		case "c":
			m.viewingCart = true
			m.viewingAccount = false
			m.accountPage = ""

		case "a":
			m.viewingCart = false
			m.viewingAccount = true

		case "up", "k":
			if m.viewingAccount && m.accountPage == "" {
				if m.accountCursor > 0 {
					m.accountCursor--
				}
			} else if !m.viewingCart && !m.viewingAccount && m.cursor > 0 {
				m.cursor--
			} else if m.viewingCart && m.cartCursor > 0 {
				m.cartCursor--
			}

		case "down", "j":
			if m.viewingAccount && m.accountPage == "" {
				if m.accountCursor < len(accountMenuItems)-1 {
					m.accountCursor++
				}
			} else if !m.viewingCart && !m.viewingAccount && m.cursor < len(m.coffees)-1 {
				m.cursor++
			} else if m.viewingCart && m.cartCursor < len(m.cart)-1 {
				m.cartCursor++
			}

		case "+", "=":
			if !m.viewingCart {
				// Increment quantity in shop view
				if item, exists := m.cart[m.cursor]; exists {
					item.Quantity++
				} else {
					m.cart[m.cursor] = &CartItem{
						Coffee:   m.coffees[m.cursor],
						Quantity: 1,
					}
				}
			} else {
				// Increment quantity in cart view
				cartItems := m.getCartItemsSlice()
				if m.cartCursor >= 0 && m.cartCursor < len(cartItems) {
					cartItems[m.cartCursor].Quantity++
				}
			}

		case "enter":
			if m.viewingAccount && m.accountPage == "" {
				switch accountMenuItems[m.accountCursor]{
				case "order history":
					m.accountPage = "orders"
				case "faq":
					m.accountPage = "faq"
				case "about":
					m.accountPage = "about"
				}
			}

		case "esc":
			if m.viewingAccount && m.accountPage != "" {
				m.accountPage = ""
			}

		case "-", "_":
			if !m.viewingCart {
				// Decrement quantity in shop view
				if item, exists := m.cart[m.cursor]; exists {
					item.Quantity--
					if item.Quantity <= 0 {
						delete(m.cart, m.cursor)
						// Reset cart cursor if we deleted the last item
						if len(m.cart) == 0 {
							m.cartCursor = 0
						} else if m.cartCursor >= len(m.cart) {
							m.cartCursor = len(m.cart) - 1
						}
					}
				}
			} else {
				// Decrement quantity in cart view
				cartItems := m.getCartItemsSlice()
				if m.cartCursor >= 0 && m.cartCursor < len(cartItems) {
					cartItems[m.cartCursor].Quantity--
					if cartItems[m.cartCursor].Quantity <= 0 {
						// Find and delete this item from the cart
						for idx, item := range m.cart {
							if item == cartItems[m.cartCursor] {
								delete(m.cart, idx)
								break
							}
						}
						// Reset cart cursor
						if len(m.cart) == 0 {
							m.cartCursor = 0
						} else if m.cartCursor >= len(m.cart) {
							m.cartCursor = len(m.cart) - 1
						}
					}
				}
			}
		}
	}
	return m, nil
}

func (m model) View() string {
	if m.windowWidth == 0 {
		m.windowWidth = 120
		m.windowHeight = 30
	}

	// Build header with cart tab
	header := m.buildHeader()

	// Build main content based on view
	var content string
	if m.viewingAccount {
		content = m.buildAccountView()
	} else if m.viewingCart {
		content = m.buildCartView()
	} else {
		content = m.buildShopView()
	}

	// Add vertical spacing around content
	contentWithPadding := lipgloss.NewStyle().
		MarginTop(1).
		MarginBottom(4).
		Render(content)

	// Build footer
	footer := m.buildFooter()

	// Combine all app content
	appContent := lipgloss.JoinVertical(
		lipgloss.Left,
		header,
		contentWithPadding,
		footer,
	)

	// Calculate vertical centering
	appHeight := lipgloss.Height(appContent)
	verticalPadding := 2 // Minimum padding from top and bottom
	availableSpace := m.windowHeight - appHeight - (verticalPadding * 2)

	if availableSpace < 0 {
		availableSpace = 0
		verticalPadding = 0
	}

	// Split remaining space between top and bottom
	topPadding := verticalPadding + (availableSpace / 2)

	// Create top spacing
	topSpacing := ""
	for i := 0; i < topPadding; i++ {
		topSpacing += "\n"
	}

	return topSpacing + appContent
}

func (m model) buildHeader() string {
	// Calculate cart total and item count
	total := 0.0
	itemCount := 0
	for _, item := range m.cart {
		total += float64(item.Quantity) * item.Coffee.Price
		itemCount += item.Quantity
	}

	// Define colors
	whiteStyle := lipgloss.NewStyle().Foreground(lipgloss.Color("#FFFFFF"))
	grayStyle := lipgloss.NewStyle().Foreground(lipgloss.Color("#AAAAAA"))
	boldWhiteStyle := lipgloss.NewStyle().Foreground(lipgloss.Color("#FFFFFF")).Bold(true)

	// Build shop tab
	var shopKeybind, shopName string
	if !m.viewingCart {
		// Active: bold white keybind and name
		shopKeybind = boldWhiteStyle.Render("s")
		shopName = boldWhiteStyle.Render("shop")
	} else {
		// Inactive: bold gray keybind, gray name
		shopKeybind = lipgloss.NewStyle().Foreground(lipgloss.Color("#AAAAAA")).Bold(true).Render("s")
		shopName = grayStyle.Render("shop")
	}

	// Build cart tab
	var cartKeybind, cartName, cartInfo string
	itemCountText := grayStyle.Render(fmt.Sprintf("[%d]", itemCount))

	if m.viewingCart {
		// Active: bold white keybind and name
		cartKeybind = boldWhiteStyle.Render("c")
		cartName = boldWhiteStyle.Render("cart")
		cartInfo = fmt.Sprintf(" %s %s",
			boldWhiteStyle.Render(fmt.Sprintf("$%.2f", total)),
			itemCountText)
	} else {
		// Inactive: bold gray keybind, gray name
		boldGrayStyle := lipgloss.NewStyle().Foreground(lipgloss.Color("#AAAAAA")).Bold(true)
		boldWhitePriceStyle := lipgloss.NewStyle().Foreground(lipgloss.Color("#FFFFFF")).Bold(true)
		cartKeybind = boldGrayStyle.Render("c")
		cartName = grayStyle.Render("cart")
		cartInfo = fmt.Sprintf(" %s %s",
			boldWhitePriceStyle.Render(fmt.Sprintf("$%.2f", total)),
			itemCountText)
	}

	// Build Account Tabs
	var accountKeybind, accountName string
	if m.viewingAccount {
		accountKeybind = boldWhiteStyle.Render("a")
		accountName = boldWhiteStyle.Render("account")
	} else {
		accountKeybind = lipgloss.NewStyle().Foreground(lipgloss.Color("#AAAAAA")).Bold(true).Render("a")
		accountName = grayStyle.Render("account")
	}

	// Build the tabs with separator only in the middle
	separator := whiteStyle.Render("|")
	tabsContent := fmt.Sprintf("%s  %s  %s  %s  %s%s %s %s %s",
		shopKeybind,
		shopName,
		separator,
		cartKeybind,
		cartName,
		cartInfo,
		separator,
		accountKeybind,
		accountName,
	)

	// Add box with padding (no vertical padding, just horizontal)
	tabBox := lipgloss.NewStyle().
		Border(lipgloss.NormalBorder()).
		Padding(0, 2).
		MarginBottom(1)

	// Center the whole thing
	centered := lipgloss.NewStyle().
		Width(m.windowWidth).
		Align(lipgloss.Center)

	return centered.Render(tabBox.Render(tabsContent))
}

func (m model) buildShopView() string {
	leftWidth := 18 // Narrower list
	leftMargin := 4 // Minimal left margin
	rightWidth := m.windowWidth - leftWidth - leftMargin - 4

	// Build the left panel (coffee list)
	leftPanel := ""
	for i, coffee := range m.coffees {
		// Apply background color when selected, white text
		if m.cursor == i {
			style := lipgloss.NewStyle().
				Background(lipgloss.Color(coffee.Color)).
				Foreground(lipgloss.Color("#FFFFFF")).
				Padding(0, 1).
				Width(leftWidth - 2).
				Align(lipgloss.Left)
			leftPanel += style.Render(coffee.Name) + "\n"
		} else {
			style := lipgloss.NewStyle().
				Foreground(lipgloss.Color("#AAAAAA")).
				Padding(0, 1).
				Width(leftWidth - 2).
				Align(lipgloss.Left)
			leftPanel += style.Render(coffee.Name) + "\n"
		}
	}

	// Add left margin to the list
	leftContainer := lipgloss.NewStyle().
		Width(leftWidth).
		MarginLeft(leftMargin)

	// Build the detail view (right panel)
	detailView := ""
	if m.cursor >= 0 && m.cursor < len(m.coffees) {
		selectedCoffee := m.coffees[m.cursor]

		nameStyle := lipgloss.NewStyle().
			Bold(true).
			Foreground(lipgloss.Color("#FFFFFF"))

		infoStyle := lipgloss.NewStyle().
			Foreground(lipgloss.Color("#AAAAAA"))

		priceStyle := lipgloss.NewStyle().
			Foreground(lipgloss.Color(selectedCoffee.Color)).
			Bold(true)

		descStyle := lipgloss.NewStyle().
			Foreground(lipgloss.Color("#FFFFFF")).
			Width(rightWidth - 4)

		quantityStyle := lipgloss.NewStyle().
			Foreground(lipgloss.Color("#FFFFFF")).
			Bold(true)

		// Get current quantity
		quantity := 0
		if item, exists := m.cart[m.cursor]; exists {
			quantity = item.Quantity
		}

		detailView += nameStyle.Render(selectedCoffee.Name) + "\n"
		detailView += infoStyle.Render(fmt.Sprintf("%s | %doz | %s",
			selectedCoffee.RoastType,
			selectedCoffee.Ounces,
			selectedCoffee.BeanType)) + "\n\n"
		detailView += priceStyle.Render(fmt.Sprintf("$%.2f", selectedCoffee.Price)) + "\n\n"
		detailView += descStyle.Render(selectedCoffee.Description) + "\n\n"
		detailView += quantityStyle.Render(fmt.Sprintf("-  %d  +", quantity)) + "\n"
	}

	detailContainer := lipgloss.NewStyle().
		Width(rightWidth)

	// Layout the panels side by side
	mainContent := lipgloss.JoinHorizontal(
		lipgloss.Top,
		leftContainer.Render(leftPanel),
		detailContainer.Render(detailView),
	)

	return mainContent
}

func (m model) buildCartView() string {
	if len(m.cart) == 0 {
		emptyStyle := lipgloss.NewStyle().
			Foreground(lipgloss.Color("#666666")).
			Align(lipgloss.Center).
			Width(m.windowWidth).
			Padding(4, 0)
		return emptyStyle.Render("Your cart is empty\n\nPress s to go back to shop")
	}

	cartItems := ""
	boxWidth := m.windowWidth - 20 // Leave some margin
	itemSlice := m.getCartItemsSlice()

	for idx, item := range itemSlice {
		itemTotal := float64(item.Quantity) * item.Coffee.Price

		// Left side: name and info
		nameStyle := lipgloss.NewStyle().
			Bold(true).
			Foreground(lipgloss.Color("#FFFFFF"))

		infoStyle := lipgloss.NewStyle().
			Foreground(lipgloss.Color("#AAAAAA"))

		// Right side: quantity controls and price
		quantityStyle := lipgloss.NewStyle().
			Foreground(lipgloss.Color("#FFFFFF"))

		priceStyle := lipgloss.NewStyle().
			Foreground(lipgloss.Color("#FFFFFF")).
			Bold(true)

		// Build content with proper spacing
		nameText := nameStyle.Render(item.Coffee.Name)
		infoText := infoStyle.Render(fmt.Sprintf("%s | %doz | %s",
			item.Coffee.RoastType,
			item.Coffee.Ounces,
			item.Coffee.BeanType))
		quantityText := quantityStyle.Render(fmt.Sprintf("-  %d  +", item.Quantity))
		priceText := priceStyle.Render(fmt.Sprintf("$%.2f", itemTotal))

		// Calculate spacing
		nameWidth := lipgloss.Width(nameText)
		quantityWidth := lipgloss.Width(quantityText)
		priceWidth := lipgloss.Width(priceText)
		spacing := boxWidth - nameWidth - quantityWidth - priceWidth - 8 // 8 for padding and gaps

		if spacing < 1 {
			spacing = 1
		}

		contentLine1 := nameText +
			lipgloss.NewStyle().Width(spacing).Render("") +
			quantityText + "  " + priceText

		contentLine2 := infoText

		boxContent := contentLine1 + "\n" + contentLine2

		// Create box for this item
		itemBox := lipgloss.NewStyle().
			Border(lipgloss.NormalBorder()).
			Padding(0, 2).
			Width(boxWidth).
			Foreground(lipgloss.Color("#FFFFFF"))

		// Center the box
		centered := lipgloss.NewStyle().
			Width(m.windowWidth).
			Align(lipgloss.Center)

		cartItems += centered.Render(itemBox.Render(boxContent))

		// Add spacing between items
		if idx < len(itemSlice)-1 {
			cartItems += "\n\n"
		}
	}

	return cartItems
}

func (m model) buildAccountView() string {
	// If we're on a subpage, show that content
	if m.accountPage != "" {
		return m.buildAccountSubpage()
	}

	// Otherwise show the account menu
	leftWidth := 18
	leftMargin := 4

	leftPanel := ""
	for i, item := range accountMenuItems {
		// Apply background color when selected, white text
		if m.accountCursor == i {
			style := lipgloss.NewStyle().
				Background(lipgloss.Color("#4682B4")).
				Foreground(lipgloss.Color("#FFFFFF")).
				Padding(0, 1).
				Width(leftWidth - 2).
				Align(lipgloss.Left)
			leftPanel += style.Render(item) + "\n"
		} else {
			style := lipgloss.NewStyle().
				Foreground(lipgloss.Color("#AAAAAA")).
				Padding(0, 1).
				Width(leftWidth - 2).
				Align(lipgloss.Left)
			leftPanel += style.Render(item) + "\n"
		}
	}

	leftContainer := lipgloss.NewStyle().
		Width(leftWidth).
		MarginLeft(leftMargin)

	return leftContainer.Render(leftPanel)
}

func (m model) buildAccountSubpage() string {
	titleStyle := lipgloss.NewStyle().
		Bold(true).
		Foreground(lipgloss.Color("#FFFFFF")).
		MarginBottom(2)

	contentStyle := lipgloss.NewStyle().
		Foreground(lipgloss.Color("#AAAAAA")).
		Width(m.windowWidth - 20).
		MarginLeft(4)

	var content string
	switch m.accountPage {
	case "orders":
		content = titleStyle.Render("Order History") + "\n\n" +
			contentStyle.Render("No orders yet. Your order history will appear here once you make a purchase.")
	case "faq":
		content = titleStyle.Render("FAQ") + "\n\n" +
			contentStyle.Render("Q: How do I place an order?\nA: Browse products with j/k, adjust quantity with +/-, and checkout via the cart.\n\nQ: What payment methods do you accept?\nA: We accept all major credit cards via Stripe.\n\nPress ESC to go back.")
	case "about":
		content = titleStyle.Render("About Terminal Coffee Shop") + "\n\n" +
			contentStyle.Render("A terminal-based coffee ordering experience.\nBuilt with Go and Bubbletea.\n\nPress ESC to go back.")
	default:
		content = "Unknown page"
	}

	return content
}

// getCartItemsSlice converts the cart map to a sorted slice for consistent iteration
func (m model) getCartItemsSlice() []*CartItem {
	items := make([]*CartItem, 0, len(m.cart))
	for _, item := range m.cart {
		items = append(items, item)
	}
	return items
}

func (m model) buildFooter() string {
	// Style for keybinds (bold)
	keybindStyle := lipgloss.NewStyle().
		Foreground(lipgloss.Color("#666666")).
		Bold(true)

	// Style for descriptions (normal)
	descStyle := lipgloss.NewStyle().
		Foreground(lipgloss.Color("#666666"))

	var footerText string
	if m.viewingAccount {
		if m.accountPage != "" {
			// In a subpage
			footerText = fmt.Sprintf("%s %s    %s %s    %s %s    %s %s",
				keybindStyle.Render("esc"),
				descStyle.Render("back"),
				keybindStyle.Render("s"),
				descStyle.Render("shop"),
				keybindStyle.Render("c"),
				descStyle.Render("cart"),
				keybindStyle.Render("q"),
				descStyle.Render("quit"),
			)
		} else {
			// In account menu
			footerText = fmt.Sprintf("%s %s    %s %s    %s %s    %s %s    %s %s",
				keybindStyle.Render("j/k"),
				descStyle.Render("menu"),
				keybindStyle.Render("enter"),
				descStyle.Render("select"),
				keybindStyle.Render("s"),
				descStyle.Render("shop"),
				keybindStyle.Render("c"),
				descStyle.Render("cart"),
				keybindStyle.Render("q"),
				descStyle.Render("quit"),
			)
		}
	} else if m.viewingCart {
		footerText = fmt.Sprintf("%s %s    %s %s    %s %s    %s %s    %s %s",
			keybindStyle.Render("j/k"),
			descStyle.Render("items"),
			keybindStyle.Render("+/-"),
			descStyle.Render("qty"),
			keybindStyle.Render("s"),
			descStyle.Render("shop"),
			keybindStyle.Render("a"),
			descStyle.Render("account"),
			keybindStyle.Render("q"),
			descStyle.Render("quit"),
		)
	} else {
		footerText = fmt.Sprintf("%s %s    %s %s    %s %s    %s %s    %s %s",
			keybindStyle.Render("j/k"),
			descStyle.Render("products"),
			keybindStyle.Render("+/-"),
			descStyle.Render("qty"),
			keybindStyle.Render("c"),
			descStyle.Render("cart"),
			keybindStyle.Render("a"),
			descStyle.Render("account"),
			keybindStyle.Render("q"),
			descStyle.Render("quit"),
		)
	}

	return lipgloss.NewStyle().
		Align(lipgloss.Center).
		Width(m.windowWidth).
		Render(footerText)
}

// InitialModel creates a new model with default coffee options
func InitialModel(username string) model {
	return model{
		username: username,
		coffees: []Coffee{
			{
				Name:        "Espresso",
				RoastType:   "Dark Roast",
				Ounces:      2,
				BeanType:    "Arabica",
				Price:       3.50,
				Color:       "#8B4513",
				Description: "A bold, concentrated shot of pure coffee bliss. Perfect for those who need an immediate caffeine injection to survive the day.",
			},
			{
				Name:        "Latte",
				RoastType:   "Medium Roast",
				Ounces:      12,
				BeanType:    "Arabica Blend",
				Price:       5.00,
				Color:       "#D2691E",
				Description: "Smooth espresso paired with steamed milk and a light layer of foam. For when you want coffee but also want to feel fancy about it.",
			},
			{
				Name:        "Cappuccino",
				RoastType:   "Medium Roast",
				Ounces:      8,
				BeanType:    "Italian Blend",
				Price:       4.50,
				Color:       "#CD853F",
				Description: "Equal parts espresso, steamed milk, and foam. The classic Italian choice for people who know what they're doing.",
			},
			{
				Name:        "Americano",
				RoastType:   "Dark Roast",
				Ounces:      16,
				BeanType:    "Arabica",
				Price:       4.00,
				Color:       "#A0522D",
				Description: "Espresso with hot water. Simple, strong, and no-nonsense. This is coffee for people who actually like the taste of coffee.",
			},
			{
				Name:        "Cold Brew",
				RoastType:   "Medium Roast",
				Ounces:      16,
				BeanType:    "Colombian",
				Price:       5.50,
				Color:       "#4682B4",
				Description: "Steeped for 12 hours to create a smooth, less acidic coffee experience. Served cold because sometimes hot coffee is just too much effort.",
			},
			{
				Name:        "Macchiato",
				RoastType:   "Dark Roast",
				Ounces:      3,
				BeanType:    "Robusta Blend",
				Price:       4.25,
				Color:       "#DAA520",
				Description: "Espresso 'marked' with a dollop of foamed milk. Small but mighty, like a tiny caffeinated warrior.",
			},
		},
		cursor:         0,
		cart:           make(map[int]*CartItem),
		cartCursor:     0,
		accountCursor:  0,
		accountPage:    "",
		windowWidth:    120,
		windowHeight:   30,
		viewingCart:    false,
		viewingAccount: false,
	}
}