package splash

import (
	"fmt"
	"os"
	"slices"
	"strings"

	"github.com/charmbracelet/bubbles/v2/key"
	tea "github.com/charmbracelet/bubbletea/v2"
	"github.com/charmbracelet/crush/internal/config"
	"github.com/charmbracelet/crush/internal/fur/provider"
	"github.com/charmbracelet/crush/internal/tui/components/chat"
	"github.com/charmbracelet/crush/internal/tui/components/completions"
	"github.com/charmbracelet/crush/internal/tui/components/core"
	"github.com/charmbracelet/crush/internal/tui/components/core/layout"
	"github.com/charmbracelet/crush/internal/tui/components/core/list"
	"github.com/charmbracelet/crush/internal/tui/components/dialogs/models"
	"github.com/charmbracelet/crush/internal/tui/components/logo"
	"github.com/charmbracelet/crush/internal/tui/styles"
	"github.com/charmbracelet/crush/internal/tui/util"
	"github.com/charmbracelet/crush/internal/version"
	"github.com/charmbracelet/lipgloss/v2"
)

type Splash interface {
	util.Model
	layout.Sizeable
	layout.Help
	Cursor() *tea.Cursor
	// SetOnboarding controls whether the splash shows model selection UI
	SetOnboarding(bool)
	// SetProjectInit controls whether the splash shows project initialization prompt
	SetProjectInit(bool)

	// Showing API key input
	IsShowingAPIKey() bool
}

const (
	SplashScreenPaddingY = 1 // Padding Y for the splash screen

	LogoGap = 6
)

// OnboardingCompleteMsg is sent when onboarding is complete
type OnboardingCompleteMsg struct{}

type splashCmp struct {
	width, height int
	keyMap        KeyMap
	logoRendered  string

	// State
	isOnboarding     bool
	needsProjectInit bool
	needsAPIKey      bool
	selectedNo       bool

	listHeight    int
	modelList     *models.ModelListComponent
	apiKeyInput   *models.APIKeyInput
	selectedModel *models.ModelOption
}

func New() Splash {
	keyMap := DefaultKeyMap()
	listKeyMap := list.DefaultKeyMap()
	listKeyMap.Down.SetEnabled(false)
	listKeyMap.Up.SetEnabled(false)
	listKeyMap.HalfPageDown.SetEnabled(false)
	listKeyMap.HalfPageUp.SetEnabled(false)
	listKeyMap.Home.SetEnabled(false)
	listKeyMap.End.SetEnabled(false)
	listKeyMap.DownOneItem = keyMap.Next
	listKeyMap.UpOneItem = keyMap.Previous

	t := styles.CurrentTheme()
	inputStyle := t.S().Base.Padding(0, 1, 0, 1)
	modelList := models.NewModelListComponent(listKeyMap, inputStyle, "Find your fave")
	apiKeyInput := models.NewAPIKeyInput()

	return &splashCmp{
		width:        0,
		height:       0,
		keyMap:       keyMap,
		logoRendered: "",
		modelList:    modelList,
		apiKeyInput:  apiKeyInput,
		selectedNo:   false,
	}
}

func (s *splashCmp) SetOnboarding(onboarding bool) {
	s.isOnboarding = onboarding
	if onboarding {
		providers, err := config.Providers()
		if err != nil {
			return
		}
		filteredProviders := []provider.Provider{}
		simpleProviders := []string{
			"anthropic",
			"openai",
			"gemini",
			"xai",
			"openrouter",
		}
		for _, p := range providers {
			if slices.Contains(simpleProviders, string(p.ID)) {
				filteredProviders = append(filteredProviders, p)
			}
		}
		s.modelList.SetProviders(filteredProviders)
	}
}

func (s *splashCmp) SetProjectInit(needsInit bool) {
	s.needsProjectInit = needsInit
}

// GetSize implements SplashPage.
func (s *splashCmp) GetSize() (int, int) {
	return s.width, s.height
}

// Init implements SplashPage.
func (s *splashCmp) Init() tea.Cmd {
	return tea.Batch(s.modelList.Init(), s.apiKeyInput.Init())
}

// SetSize implements SplashPage.
func (s *splashCmp) SetSize(width int, height int) tea.Cmd {
	s.height = height
	if width != s.width {
		s.width = width
		s.logoRendered = s.logoBlock()
	}
	// remove padding, logo height, gap, title space
	s.listHeight = s.height - lipgloss.Height(s.logoRendered) - (SplashScreenPaddingY * 2) - s.logoGap() - 2
	listWidth := min(60, width)
	return s.modelList.SetSize(listWidth, s.listHeight)
}

// Update implements SplashPage.
func (s *splashCmp) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
	switch msg := msg.(type) {
	case tea.WindowSizeMsg:
		return s, s.SetSize(msg.Width, msg.Height)
	case tea.KeyPressMsg:
		switch {
		case key.Matches(msg, s.keyMap.Back):
			if s.needsAPIKey {
				// Go back to model selection
				s.needsAPIKey = false
				s.selectedModel = nil
				return s, nil
			}
		case key.Matches(msg, s.keyMap.Select):
			if s.isOnboarding && !s.needsAPIKey {
				modelInx := s.modelList.SelectedIndex()
				items := s.modelList.Items()
				selectedItem := items[modelInx].(completions.CompletionItem).Value().(models.ModelOption)
				if s.isProviderConfigured(string(selectedItem.Provider.ID)) {
					cmd := s.setPreferredModel(selectedItem)
					s.isOnboarding = false
					return s, tea.Batch(cmd, util.CmdHandler(OnboardingCompleteMsg{}))
				} else {
					// Provider not configured, show API key input
					s.needsAPIKey = true
					s.selectedModel = &selectedItem
					s.apiKeyInput.SetProviderName(selectedItem.Provider.Name)
					return s, nil
				}
			} else if s.needsAPIKey {
				// Handle API key submission
				apiKey := s.apiKeyInput.Value()
				if apiKey != "" {
					return s, s.saveAPIKeyAndContinue(apiKey)
				}
			} else if s.needsProjectInit {
				return s, s.initializeProject()
			}
		case key.Matches(msg, s.keyMap.Tab, s.keyMap.LeftRight):
			if s.needsProjectInit {
				s.selectedNo = !s.selectedNo
				return s, nil
			}
		case key.Matches(msg, s.keyMap.Yes):
			if s.needsProjectInit {
				return s, s.initializeProject()
			}
		case key.Matches(msg, s.keyMap.No):
			if s.needsProjectInit {
				s.needsProjectInit = false
				return s, util.CmdHandler(OnboardingCompleteMsg{})
			}
		default:
			if s.needsAPIKey {
				u, cmd := s.apiKeyInput.Update(msg)
				s.apiKeyInput = u.(*models.APIKeyInput)
				return s, cmd
			} else if s.isOnboarding {
				u, cmd := s.modelList.Update(msg)
				s.modelList = u
				return s, cmd
			}
		}
	case tea.PasteMsg:
		if s.needsAPIKey {
			u, cmd := s.apiKeyInput.Update(msg)
			s.apiKeyInput = u.(*models.APIKeyInput)
			return s, cmd
		} else if s.isOnboarding {
			var cmd tea.Cmd
			s.modelList, cmd = s.modelList.Update(msg)
			return s, cmd
		}
	}
	return s, nil
}

func (s *splashCmp) saveAPIKeyAndContinue(apiKey string) tea.Cmd {
	if s.selectedModel == nil {
		return util.ReportError(fmt.Errorf("no model selected"))
	}

	cfg := config.Get()
	err := cfg.SetProviderAPIKey(string(s.selectedModel.Provider.ID), apiKey)
	if err != nil {
		return util.ReportError(fmt.Errorf("failed to save API key: %w", err))
	}

	// Reset API key state and continue with model selection
	s.needsAPIKey = false
	cmd := s.setPreferredModel(*s.selectedModel)
	s.isOnboarding = false
	s.selectedModel = nil

	return tea.Batch(cmd, util.CmdHandler(OnboardingCompleteMsg{}))
}

func (s *splashCmp) initializeProject() tea.Cmd {
	s.needsProjectInit = false
	prompt := `Please analyze this codebase and create a CRUSH.md file containing:
1. Build/lint/test commands - especially for running a single test
2. Code style guidelines including imports, formatting, types, naming conventions, error handling, etc.

The file you create will be given to agentic coding agents (such as yourself) that operate in this repository. Make it about 20 lines long.
If there's already a CRUSH.md, improve it.
If there are Cursor rules (in .cursor/rules/ or .cursorrules) or Copilot rules (in .github/copilot-instructions.md), make sure to include them.
Add the .crush directory to the .gitignore file if it's not already there.`

	if err := config.MarkProjectInitialized(); err != nil {
		return util.ReportError(err)
	}
	var cmds []tea.Cmd

	cmds = append(cmds, util.CmdHandler(OnboardingCompleteMsg{}))
	if !s.selectedNo {
		cmds = append(cmds,
			util.CmdHandler(chat.SessionClearedMsg{}),
			util.CmdHandler(chat.SendMsg{
				Text: prompt,
			}),
		)
	}
	return tea.Sequence(cmds...)
}

func (s *splashCmp) setPreferredModel(selectedItem models.ModelOption) tea.Cmd {
	cfg := config.Get()
	model := cfg.GetModel(string(selectedItem.Provider.ID), selectedItem.Model.ID)
	if model == nil {
		return util.ReportError(fmt.Errorf("model %s not found for provider %s", selectedItem.Model.ID, selectedItem.Provider.ID))
	}

	selectedModel := config.SelectedModel{
		Model:           selectedItem.Model.ID,
		Provider:        string(selectedItem.Provider.ID),
		ReasoningEffort: model.DefaultReasoningEffort,
		MaxTokens:       model.DefaultMaxTokens,
	}

	err := cfg.UpdatePreferredModel(config.SelectedModelTypeLarge, selectedModel)
	if err != nil {
		return util.ReportError(err)
	}

	// Now lets automatically setup the small model
	knownProvider, err := s.getProvider(selectedItem.Provider.ID)
	if err != nil {
		return util.ReportError(err)
	}
	if knownProvider == nil {
		// for local provider we just use the same model
		err = cfg.UpdatePreferredModel(config.SelectedModelTypeSmall, selectedModel)
		if err != nil {
			return util.ReportError(err)
		}
	} else {
		smallModel := knownProvider.DefaultSmallModelID
		model := cfg.GetModel(string(selectedItem.Provider.ID), smallModel)
		// should never happen
		if model == nil {
			err = cfg.UpdatePreferredModel(config.SelectedModelTypeSmall, selectedModel)
			if err != nil {
				return util.ReportError(err)
			}
			return nil
		}
		smallSelectedModel := config.SelectedModel{
			Model:           smallModel,
			Provider:        string(selectedItem.Provider.ID),
			ReasoningEffort: model.DefaultReasoningEffort,
			MaxTokens:       model.DefaultMaxTokens,
		}
		err = cfg.UpdatePreferredModel(config.SelectedModelTypeSmall, smallSelectedModel)
		if err != nil {
			return util.ReportError(err)
		}
	}
	return nil
}

func (s *splashCmp) getProvider(providerID provider.InferenceProvider) (*provider.Provider, error) {
	providers, err := config.Providers()
	if err != nil {
		return nil, err
	}
	for _, p := range providers {
		if p.ID == providerID {
			return &p, nil
		}
	}
	return nil, nil
}

func (s *splashCmp) isProviderConfigured(providerID string) bool {
	cfg := config.Get()
	if _, ok := cfg.Providers[providerID]; ok {
		return true
	}
	return false
}

func (s *splashCmp) View() string {
	t := styles.CurrentTheme()
	var content string
	if s.needsAPIKey {
		remainingHeight := s.height - lipgloss.Height(s.logoRendered) - (SplashScreenPaddingY * 2)
		apiKeyView := t.S().Base.PaddingLeft(1).Render(s.apiKeyInput.View())
		apiKeySelector := t.S().Base.AlignVertical(lipgloss.Bottom).Height(remainingHeight).Render(
			lipgloss.JoinVertical(
				lipgloss.Left,
				apiKeyView,
			),
		)
		content = lipgloss.JoinVertical(
			lipgloss.Left,
			s.logoRendered,
			apiKeySelector,
		)
	} else if s.isOnboarding {
		modelListView := s.modelList.View()
		remainingHeight := s.height - lipgloss.Height(s.logoRendered) - (SplashScreenPaddingY * 2)
		modelSelector := t.S().Base.AlignVertical(lipgloss.Bottom).Height(remainingHeight).Render(
			lipgloss.JoinVertical(
				lipgloss.Left,
				t.S().Base.PaddingLeft(1).Foreground(t.Primary).Render("Choose a Model"),
				"",
				modelListView,
			),
		)
		content = lipgloss.JoinVertical(
			lipgloss.Left,
			s.logoRendered,
			modelSelector,
		)
	} else if s.needsProjectInit {
		titleStyle := t.S().Base.Foreground(t.FgBase)
		bodyStyle := t.S().Base.Foreground(t.FgMuted)
		shortcutStyle := t.S().Base.Foreground(t.Success)

		initText := lipgloss.JoinVertical(
			lipgloss.Left,
			titleStyle.Render("Would you like to initialize this project?"),
			"",
			bodyStyle.Render("When I initialize your codebase I examine the project and put the"),
			bodyStyle.Render("result into a CRUSH.md file which serves as general context."),
			"",
			bodyStyle.Render("You can also initialize anytime via ")+shortcutStyle.Render("ctrl+p")+bodyStyle.Render("."),
			"",
			bodyStyle.Render("Would you like to initialize now?"),
		)

		yesButton := core.SelectableButton(core.ButtonOpts{
			Text:           "Yep!",
			UnderlineIndex: 0,
			Selected:       !s.selectedNo,
		})

		noButton := core.SelectableButton(core.ButtonOpts{
			Text:           "Nope",
			UnderlineIndex: 0,
			Selected:       s.selectedNo,
		})

		buttons := lipgloss.JoinHorizontal(lipgloss.Left, yesButton, "  ", noButton)
		infoSection := s.infoSection()

		remainingHeight := s.height - lipgloss.Height(s.logoRendered) - (SplashScreenPaddingY * 2) - lipgloss.Height(infoSection)

		initContent := t.S().Base.AlignVertical(lipgloss.Bottom).PaddingLeft(1).Height(remainingHeight).Render(
			lipgloss.JoinVertical(
				lipgloss.Left,
				initText,
				"",
				buttons,
			),
		)

		content = lipgloss.JoinVertical(
			lipgloss.Left,
			s.logoRendered,
			infoSection,
			initContent,
		)
	} else {
		parts := []string{
			s.logoRendered,
			s.infoSection(),
		}
		content = lipgloss.JoinVertical(lipgloss.Left, parts...)
	}

	return t.S().Base.
		Width(s.width).
		Height(s.height).
		PaddingTop(SplashScreenPaddingY).
		PaddingBottom(SplashScreenPaddingY).
		Render(content)
}

func (s *splashCmp) Cursor() *tea.Cursor {
	if s.needsAPIKey {
		cursor := s.apiKeyInput.Cursor()
		if cursor != nil {
			return s.moveCursor(cursor)
		}
	} else if s.isOnboarding {
		cursor := s.modelList.Cursor()
		if cursor != nil {
			return s.moveCursor(cursor)
		}
	} else {
		return nil
	}
	return nil
}

func (s *splashCmp) infoSection() string {
	t := styles.CurrentTheme()
	return t.S().Base.PaddingLeft(2).Render(
		lipgloss.JoinVertical(
			lipgloss.Left,
			s.cwd(),
			"",
			lipgloss.JoinHorizontal(lipgloss.Left, s.lspBlock(), s.mcpBlock()),
			"",
		),
	)
}

func (s *splashCmp) logoBlock() string {
	t := styles.CurrentTheme()
	return t.S().Base.Padding(0, 2).Width(s.width).Render(
		logo.Render(version.Version, false, logo.Opts{
			FieldColor:   t.Primary,
			TitleColorA:  t.Secondary,
			TitleColorB:  t.Primary,
			CharmColor:   t.Secondary,
			VersionColor: t.Primary,
			Width:        s.width - 4,
		}),
	)
}

func (s *splashCmp) moveCursor(cursor *tea.Cursor) *tea.Cursor {
	if cursor == nil {
		return nil
	}
	// Calculate the correct Y offset based on current state
	logoHeight := lipgloss.Height(s.logoRendered)
	if s.needsAPIKey {
		infoSectionHeight := lipgloss.Height(s.infoSection())
		baseOffset := logoHeight + SplashScreenPaddingY + infoSectionHeight
		remainingHeight := s.height - baseOffset - lipgloss.Height(s.apiKeyInput.View()) - SplashScreenPaddingY
		offset := baseOffset + remainingHeight
		cursor.Y += offset
		cursor.X = cursor.X + 1
	} else if s.isOnboarding {
		offset := logoHeight + SplashScreenPaddingY + s.logoGap() + 3
		cursor.Y += offset
		cursor.X = cursor.X + 1
	}

	return cursor
}

func (s *splashCmp) logoGap() int {
	if s.height > 35 {
		return LogoGap
	}
	return 0
}

// Bindings implements SplashPage.
func (s *splashCmp) Bindings() []key.Binding {
	if s.needsAPIKey {
		return []key.Binding{
			s.keyMap.Select,
			s.keyMap.Back,
		}
	} else if s.isOnboarding {
		return []key.Binding{
			s.keyMap.Select,
			s.keyMap.Next,
			s.keyMap.Previous,
		}
	} else if s.needsProjectInit {
		return []key.Binding{
			s.keyMap.Select,
			s.keyMap.Yes,
			s.keyMap.No,
			s.keyMap.Tab,
			s.keyMap.LeftRight,
		}
	}
	return []key.Binding{}
}

func (s *splashCmp) getMaxInfoWidth() int {
	return min(s.width-2, 40) // 2 for left padding
}

func (s *splashCmp) cwd() string {
	cwd := config.Get().WorkingDir()
	t := styles.CurrentTheme()
	homeDir, err := os.UserHomeDir()
	if err == nil && cwd != homeDir {
		cwd = strings.ReplaceAll(cwd, homeDir, "~")
	}
	maxWidth := s.getMaxInfoWidth()
	return t.S().Muted.Width(maxWidth).Render(cwd)
}

func LSPList(maxWidth int) []string {
	t := styles.CurrentTheme()
	lspList := []string{}
	lsp := config.Get().LSP.Sorted()
	if len(lsp) == 0 {
		return []string{t.S().Base.Foreground(t.Border).Render("None")}
	}
	for _, l := range lsp {
		iconColor := t.Success
		if l.LSP.Disabled {
			iconColor = t.FgMuted
		}
		lspList = append(lspList,
			core.Status(
				core.StatusOpts{
					IconColor:   iconColor,
					Title:       l.Name,
					Description: l.LSP.Command,
				},
				maxWidth,
			),
		)
	}
	return lspList
}

func (s *splashCmp) lspBlock() string {
	t := styles.CurrentTheme()
	maxWidth := s.getMaxInfoWidth() / 2
	section := t.S().Subtle.Render("LSPs")
	lspList := append([]string{section, ""}, LSPList(maxWidth-1)...)
	return t.S().Base.Width(maxWidth).PaddingRight(1).Render(
		lipgloss.JoinVertical(
			lipgloss.Left,
			lspList...,
		),
	)
}

func MCPList(maxWidth int) []string {
	t := styles.CurrentTheme()
	mcpList := []string{}
	mcps := config.Get().MCP.Sorted()
	if len(mcps) == 0 {
		return []string{t.S().Base.Foreground(t.Border).Render("None")}
	}
	for _, l := range mcps {
		iconColor := t.Success
		if l.MCP.Disabled {
			iconColor = t.FgMuted
		}
		mcpList = append(mcpList,
			core.Status(
				core.StatusOpts{
					IconColor:   iconColor,
					Title:       l.Name,
					Description: l.MCP.Command,
				},
				maxWidth,
			),
		)
	}
	return mcpList
}

func (s *splashCmp) mcpBlock() string {
	t := styles.CurrentTheme()
	maxWidth := s.getMaxInfoWidth() / 2
	section := t.S().Subtle.Render("MCPs")
	mcpList := append([]string{section, ""}, MCPList(maxWidth-1)...)
	return t.S().Base.Width(maxWidth).PaddingRight(1).Render(
		lipgloss.JoinVertical(
			lipgloss.Left,
			mcpList...,
		),
	)
}

func (s *splashCmp) IsShowingAPIKey() bool {
	return s.needsAPIKey
}