lmcli/pkg/tui/tui.go

package tui

// The terminal UI for lmcli, launched from the `lmcli chat` command
// TODO:
// - conversation list view
// - change model
// - rename conversation
// - set system prompt
// - system prompt library?

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"
	"time"

	cmdutil "git.mlow.ca/mlow/lmcli/pkg/cmd/util"
	"git.mlow.ca/mlow/lmcli/pkg/lmcli"
	models "git.mlow.ca/mlow/lmcli/pkg/lmcli/model"
	"github.com/charmbracelet/bubbles/spinner"
	"github.com/charmbracelet/bubbles/textarea"
	"github.com/charmbracelet/bubbles/viewport"
	tea "github.com/charmbracelet/bubbletea"
	"github.com/charmbracelet/lipgloss"
	"github.com/muesli/reflow/ansi"
	"github.com/muesli/reflow/wordwrap"
	"gopkg.in/yaml.v2"
)

type focusState int

const (
	focusInput focusState = iota
	focusMessages
)

type editorTarget int

const (
	input editorTarget = iota
	selectedMessage
)

type uiCache struct {
	header  string
	content string
	error   string
	input   string
	footer  string
}

type model struct {
	width  int
	height int

	ctx           *lmcli.Context
	convShortname string

	// application state
	conversation    *models.Conversation
	messages        []models.Message
	waitingForReply bool
	editorTarget    editorTarget
	stopSignal      chan interface{}
	replyChan       chan models.Message
	replyChunkChan  chan string
	persistence     bool // whether we will save new messages in the conversation
	err             error

	// ui state
	focus           focusState
	wrap            bool     // whether message content is wrapped to viewport width
	status          string   // a general status message
	showToolResults bool     // whether tool calls and results are shown
	messageCache    []string // cache of syntax highlighted and wrapped message content
	messageOffsets  []int
	selectedMessage int

	// ui elements
	content viewport.Model
	input   textarea.Model
	spinner spinner.Model

	cache *uiCache
}

type message struct {
	role    string
	content string
}

// custom tea.Msg types
type (
	// sent on each chunk received from LLM
	msgResponseChunk string
	// sent when response is finished being received
	msgResponseEnd string
	// a special case of msgError that stops the response waiting animation
	msgResponseError error
	// sent on each completed reply
	msgAssistantReply models.Message
	// sent when a conversation is (re)loaded
	msgConversationLoaded *models.Conversation
	// sent when a new conversation title is set
	msgConversationTitleChanged string
	// send when a conversation's messages are laoded
	msgMessagesLoaded []models.Message
	// sent when an error occurs
	msgError error
)

// styles
var (
	headingStyle = lipgloss.NewStyle().
			MarginTop(1).
			MarginBottom(1).
			PaddingLeft(1).
			Bold(true)
	userStyle      = lipgloss.NewStyle().Faint(true).Foreground(lipgloss.Color("10"))
	assistantStyle = lipgloss.NewStyle().Faint(true).Foreground(lipgloss.Color("12"))
	messageStyle   = lipgloss.NewStyle().
			PaddingLeft(2).
			PaddingRight(2)
	headerStyle = lipgloss.NewStyle().
			PaddingLeft(1).
			PaddingRight(1).
			Background(lipgloss.Color("0"))
	footerStyle = lipgloss.NewStyle()
)

func (m model) Init() tea.Cmd {
	return tea.Batch(
		textarea.Blink,
		m.spinner.Tick,
		m.loadConversation(m.convShortname),
		m.waitForChunk(),
		m.waitForReply(),
	)
}

func wrapError(err error) tea.Cmd {
	return func() tea.Msg {
		return msgError(err)
	}
}

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

	switch msg := msg.(type) {
	case msgTempfileEditorClosed:
		contents := string(msg)
		switch m.editorTarget {
		case input:
			m.input.SetValue(contents)
		case selectedMessage:
			m.setMessageContents(m.selectedMessage, contents)
			if m.persistence && m.messages[m.selectedMessage].ID > 0 {
				// update persisted message
				err := m.ctx.Store.UpdateMessage(&m.messages[m.selectedMessage])
				if err != nil {
					cmds = append(cmds, wrapError(fmt.Errorf("Could not save edited message: %v", err)))
				}
			}
			m.updateContent()
		}
	case tea.KeyMsg:
		switch msg.String() {
		case "ctrl+c":
			if m.waitingForReply {
				m.stopSignal <- ""
				return m, nil
			} else {
				return m, tea.Quit
			}
		case "ctrl+p":
			m.persistence = !m.persistence
		case "ctrl+w":
			m.wrap = !m.wrap
			m.rebuildMessageCache()
			m.updateContent()
		case "ctrl+t":
			m.showToolResults = !m.showToolResults
			m.rebuildMessageCache()
			m.updateContent()
		case "q":
			if m.focus != focusInput {
				return m, tea.Quit
			}
		default:
			var inputHandled tea.Cmd
			switch m.focus {
			case focusInput:
				inputHandled = m.handleInputKey(msg)
			case focusMessages:
				inputHandled = m.handleMessagesKey(msg)
			}
			if inputHandled != nil {
				return m, inputHandled
			}
		}
	case tea.WindowSizeMsg:
		m.width = msg.Width
		m.height = msg.Height
		m.content.Width = msg.Width
		m.input.SetWidth(msg.Width-m.input.FocusedStyle.Base.GetHorizontalBorderSize())
		m.rebuildMessageCache()
		m.updateContent()
	case msgConversationLoaded:
		m.conversation = (*models.Conversation)(msg)
		cmds = append(cmds, m.loadMessages(m.conversation))
	case msgMessagesLoaded:
		m.setMessages(msg)
		m.updateContent()
	case msgResponseChunk:
		chunk := string(msg)
		last := len(m.messages) - 1
		if last >= 0 && m.messages[last].Role.IsAssistant() {
			m.setMessageContents(last, m.messages[last].Content+chunk)
		} else {
			m.addMessage(models.Message{
				Role:    models.MessageRoleAssistant,
				Content: chunk,
			})
		}
		m.updateContent()
		cmds = append(cmds, m.waitForChunk()) // wait for the next chunk
	case msgAssistantReply:
		// the last reply that was being worked on is finished
		reply := models.Message(msg)
		reply.Content = strings.TrimSpace(reply.Content)

		last := len(m.messages) - 1
		if last < 0 {
			panic("Unexpected empty messages handling msgAssistantReply")
		}

		if reply.Role.IsAssistant() && m.messages[last].Role.IsAssistant() {
			// this was a continuation, so replace the previous message with the completed reply
			m.setMessage(last, reply)
		} else {
			m.addMessage(reply)
		}

		if m.persistence {
			var err error
			if m.conversation.ID == 0 {
				err = m.ctx.Store.SaveConversation(m.conversation)
			}
			if err != nil {
				cmds = append(cmds, wrapError(err))
			} else {
				cmds = append(cmds, m.persistConversation())
			}
		}

		if m.conversation.Title == "" {
			cmds = append(cmds, m.generateConversationTitle())
		}

		m.updateContent()
		cmds = append(cmds, m.waitForReply())
	case msgResponseEnd:
		m.waitingForReply = false
		last := len(m.messages) - 1
		if last < 0 {
			panic("Unexpected empty messages handling msgResponseEnd")
		}
		m.setMessageContents(last, strings.TrimSpace(m.messages[last].Content))
		m.updateContent()
		m.status = "Press ctrl+s to send"
	case msgResponseError:
		m.waitingForReply = false
		m.status = "Press ctrl+s to send"
		m.err = error(msg)
	case msgConversationTitleChanged:
		title := string(msg)
		m.conversation.Title = title
		if m.persistence {
			err := m.ctx.Store.SaveConversation(m.conversation)
			if err != nil {
				cmds = append(cmds, wrapError(err))
			}
		}
	case msgError:
		m.err = error(msg)
	}

	var cmd tea.Cmd
	m.spinner, cmd = m.spinner.Update(msg)
	if cmd != nil {
		cmds = append(cmds, cmd)
	}


	prevInputLineCnt := m.input.LineCount()
	inputCaptured := false
	m.input, cmd = m.input.Update(msg)
	if cmd != nil {
		inputCaptured = true
		cmds = append(cmds, cmd)
	}

	if !inputCaptured {
		m.content, cmd = m.content.Update(msg)
		if cmd != nil {
			cmds = append(cmds, cmd)
		}
	}

	if m.width > 0 {
		m.cache.header = m.headerView()
		m.cache.footer = m.footerView()
		m.cache.error = m.errorView()

		fixedHeight := height(m.cache.header) + height(m.cache.error) + height(m.cache.footer)

		// calculate clamped input height to accomodate input text
		newHeight := max(4, min((m.height-fixedHeight-1)/2, m.input.LineCount()))
		m.input.SetHeight(newHeight)
		m.cache.input = m.inputView()

		m.content.Height = m.height - height(m.cache.input) - fixedHeight
		m.cache.content = m.contentView()
	}

	// this is a pretty nasty hack to ensure the input area viewport doesn't
	// scroll below its content, which can happen when the input viewport
	// height has grown, or previously entered lines have been deleted
	if prevInputLineCnt != m.input.LineCount() {
		// dist is the distance we'd need to scroll up from the current cursor
		// position to position the last input line at the bottom of the
		// viewport. if negative, we're already scrolled above the bottom
		dist := m.input.Line() - (m.input.LineCount() - m.input.Height())
		if dist > 0 {
			for i := 0; i < dist; i++ {
				// move cursor up until content reaches the bottom of the viewport
				m.input.CursorUp()
			}
			m.input, cmd = m.input.Update(nil)
			cmds = append(cmds, cmd)
			for i := 0; i < dist; i++ {
				// move cursor back down to its previous position
				m.input.CursorDown()
			}
			m.input, cmd = m.input.Update(nil)
			cmds = append(cmds, cmd)
		}
	}

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

func height(str string) int {
	if str == "" {
		return 0
	}
	return strings.Count(str, "\n") + 1
}

func truncateToCellWidth(str string, width int, tail string) string {
	cellWidth := ansi.PrintableRuneWidth(str)
	if cellWidth <= width {
		return str
	}
	tailWidth := ansi.PrintableRuneWidth(tail)
	for {
		str = str[:len(str)-((cellWidth+tailWidth)-width)]
		cellWidth = ansi.PrintableRuneWidth(str)
		if cellWidth+tailWidth <= max(width, 0) {
			break
		}
	}
	return str + tail
}

func (m model) View() string {
	if m.width == 0 {
		// this is the case upon initial startup, but it's also a safe bet that
		// we can just skip rendering if the terminal is really 0 width...
		// without this, the m.*View() functions may crash
		return ""
	}

	sections := make([]string, 0, 6)
	sections = append(sections, m.cache.header)
	sections = append(sections, m.cache.content)
	if m.cache.error != "" {
		sections = append(sections, m.cache.error)
	}
	sections = append(sections, m.cache.input)
	sections = append(sections, m.cache.footer)

	return lipgloss.JoinVertical(
		lipgloss.Left,
		sections...,
	)
}

func (m *model) headerView() string {
	titleStyle := lipgloss.NewStyle().Bold(true)
	var title string
	if m.conversation != nil && m.conversation.Title != "" {
		title = m.conversation.Title
	} else {
		title = "Untitled"
	}
	title = truncateToCellWidth(title, m.width-headerStyle.GetHorizontalPadding(), "...")
	part := titleStyle.Render(title)
	return headerStyle.Width(m.width).Render(part)
}

func (m *model) contentView() string {
	return m.content.View()
}

func (m *model) errorView() string {
	if m.err == nil {
		return ""
	}
	return lipgloss.NewStyle().
		Width(m.width).
		AlignHorizontal(lipgloss.Center).
		Bold(true).
		Foreground(lipgloss.Color("1")).
		Render(fmt.Sprintf("%s", m.err))
}

func (m *model) inputView() string {
	return m.input.View()
}

func (m *model) footerView() string {
	segmentStyle := lipgloss.NewStyle().PaddingLeft(1).PaddingRight(1).Faint(true)
	segmentSeparator := "|"

	savingStyle := segmentStyle.Copy().Bold(true)
	saving := ""
	if m.persistence {
		saving = savingStyle.Foreground(lipgloss.Color("2")).Render("✅💾")
	} else {
		saving = savingStyle.Foreground(lipgloss.Color("1")).Render("❌💾")
	}

	status := m.status
	if m.waitingForReply {
		status += m.spinner.View()
	}

	leftSegments := []string{
		saving,
		segmentStyle.Render(status),
	}
	rightSegments := []string{
		segmentStyle.Render(fmt.Sprintf("Model: %s", *m.ctx.Config.Defaults.Model)),
	}

	left := strings.Join(leftSegments, segmentSeparator)
	right := strings.Join(rightSegments, segmentSeparator)

	totalWidth := lipgloss.Width(left) + lipgloss.Width(right)
	remaining := m.width - totalWidth

	var padding string
	if remaining > 0 {
		padding = strings.Repeat(" ", remaining)
	}

	footer := left + padding + right
	if remaining < 0 {
		footer = truncateToCellWidth(footer, m.width, "...")
	}
	return footerStyle.Width(m.width).Render(footer)
}

func initialModel(ctx *lmcli.Context, convShortname string) model {
	m := model{
		ctx:           ctx,
		convShortname: convShortname,
		conversation:  &models.Conversation{},
		persistence:   true,

		stopSignal:     make(chan interface{}),
		replyChan:      make(chan models.Message),
		replyChunkChan: make(chan string),

		wrap:            true,
		selectedMessage: -1,

		cache: &uiCache{},
	}

	m.content = viewport.New(0, 0)

	m.input = textarea.New()
	m.input.CharLimit = 0
	m.input.Placeholder = "Enter a message"

	m.input.ShowLineNumbers = false
	m.input.Focus()
	m.input.FocusedStyle.CursorLine = lipgloss.NewStyle()
	m.input.FocusedStyle.Base = lipgloss.NewStyle().
		Border(lipgloss.RoundedBorder(), true, true, true, false)
	m.input.BlurredStyle.Base = lipgloss.NewStyle().
		Faint(true).
		Border(lipgloss.RoundedBorder(), true, true, true, false)

	m.spinner = spinner.New(spinner.WithSpinner(
		spinner.Spinner{
			Frames: []string{
				".  ",
				".. ",
				"...",
				".. ",
				".  ",
				"   ",
			},
			FPS: time.Second / 3,
		},
	))

	m.waitingForReply = false
	m.status = "Press ctrl+s to send"
	return m
}

// fraction is the fraction of the total screen height into view the offset
// should be scrolled into view. 0.5 = items will be snapped to middle of
// view
func scrollIntoView(vp *viewport.Model, offset int, fraction float32) {
	currentOffset := vp.YOffset
	if offset >= currentOffset && offset < currentOffset+vp.Height {
		return
	}
	distance := currentOffset - offset
	if distance < 0 {
		// we should scroll down until it just comes into view
		vp.SetYOffset(currentOffset - (distance + (vp.Height - int(float32(vp.Height)*fraction))) + 1)
	} else {
		// we should scroll up
		vp.SetYOffset(currentOffset - distance - int(float32(vp.Height)*fraction))
	}
}

func (m *model) handleMessagesKey(msg tea.KeyMsg) tea.Cmd {
	switch msg.String() {
	case "tab":
		m.focus = focusInput
		m.updateContent()
		m.input.Focus()
	case "e":
		message := m.messages[m.selectedMessage]
		cmd := openTempfileEditor("message.*.md", message.Content, "# Edit the message below\n")
		m.editorTarget = selectedMessage
		return cmd
	case "ctrl+k":
		if m.selectedMessage > 0 && len(m.messages) == len(m.messageOffsets) {
			m.selectedMessage--
			m.updateContent()
			offset := m.messageOffsets[m.selectedMessage]
			scrollIntoView(&m.content, offset, 0.1)
		}
	case "ctrl+j":
		if m.selectedMessage < len(m.messages)-1 && len(m.messages) == len(m.messageOffsets) {
			m.selectedMessage++
			m.updateContent()
			offset := m.messageOffsets[m.selectedMessage]
			scrollIntoView(&m.content, offset, 0.1)
		}
	case "ctrl+r":
		// resubmit the conversation with all messages up until and including the selected message
		if m.waitingForReply || len(m.messages) == 0 {
			return nil
		}
		m.messages = m.messages[:m.selectedMessage+1]
		m.messageCache = m.messageCache[:m.selectedMessage+1]
		m.updateContent()
		m.content.GotoBottom()
		return m.promptLLM()
	}
	return nil
}

func (m *model) handleInputKey(msg tea.KeyMsg) tea.Cmd {
	switch msg.String() {
	case "esc":
		m.focus = focusMessages
		if len(m.messages) > 0 {
			if m.selectedMessage < 0 || m.selectedMessage >= len(m.messages) {
				m.selectedMessage = len(m.messages) - 1
			}
			offset := m.messageOffsets[m.selectedMessage]
			scrollIntoView(&m.content, offset, 0.1)
		}
		m.updateContent()
		m.input.Blur()
	case "ctrl+s":
		userInput := strings.TrimSpace(m.input.Value())
		if strings.TrimSpace(userInput) == "" {
			return nil
		}

		if len(m.messages) > 0 && m.messages[len(m.messages)-1].Role == models.MessageRoleUser {
			return wrapError(fmt.Errorf("Can't reply to a user message"))
		}

		reply := models.Message{
			Role:    models.MessageRoleUser,
			Content: userInput,
		}

		if m.persistence {
			var err error
			if m.conversation.ID == 0 {
				err = m.ctx.Store.SaveConversation(m.conversation)
			}
			if err != nil {
				return wrapError(err)
			}

			// ensure all messages up to the one we're about to add are persisted
			cmd := m.persistConversation()
			if cmd != nil {
				return cmd
			}

			savedReply, err := m.ctx.Store.AddReply(m.conversation, reply)
			if err != nil {
				return wrapError(err)
			}
			reply = *savedReply
		}

		m.input.SetValue("")
		m.addMessage(reply)

		m.updateContent()
		m.content.GotoBottom()
		return m.promptLLM()
	case "ctrl+e":
		cmd := openTempfileEditor("message.*.md", m.input.Value(), "# Edit your input below\n")
		m.editorTarget = input
		return cmd
	}
	return nil
}

func (m *model) loadConversation(shortname string) tea.Cmd {
	return func() tea.Msg {
		if shortname == "" {
			return nil
		}
		c, err := m.ctx.Store.ConversationByShortName(shortname)
		if err != nil {
			return msgError(fmt.Errorf("Could not lookup conversation: %v", err))
		}
		if c.ID == 0 {
			return msgError(fmt.Errorf("Conversation not found: %s", shortname))
		}
		return msgConversationLoaded(c)
	}
}

func (m *model) loadMessages(c *models.Conversation) tea.Cmd {
	return func() tea.Msg {
		messages, err := m.ctx.Store.Messages(c)
		if err != nil {
			return msgError(fmt.Errorf("Could not load conversation messages: %v\n", err))
		}
		return msgMessagesLoaded(messages)
	}
}

func (m *model) waitForReply() tea.Cmd {
	return func() tea.Msg {
		return msgAssistantReply(<-m.replyChan)
	}
}

func (m *model) waitForChunk() tea.Cmd {
	return func() tea.Msg {
		return msgResponseChunk(<-m.replyChunkChan)
	}
}

func (m *model) generateConversationTitle() tea.Cmd {
	return func() tea.Msg {
		title, err := cmdutil.GenerateTitle(m.ctx, m.conversation)
		if err != nil {
			return msgError(err)
		}
		return msgConversationTitleChanged(title)
	}
}

func (m *model) promptLLM() tea.Cmd {
	m.waitingForReply = true
	m.status = "Press ctrl+c to cancel"

	return func() tea.Msg {
		completionProvider, err := m.ctx.GetCompletionProvider(*m.ctx.Config.Defaults.Model)
		if err != nil {
			return msgError(err)
		}

		requestParams := models.RequestParameters{
			Model:       *m.ctx.Config.Defaults.Model,
			MaxTokens:   *m.ctx.Config.Defaults.MaxTokens,
			Temperature: *m.ctx.Config.Defaults.Temperature,
			ToolBag:     m.ctx.EnabledTools,
		}

		replyHandler := func(msg models.Message) {
			m.replyChan <- msg
		}

		ctx, cancel := context.WithCancel(context.Background())

		canceled := false
		go func() {
			select {
			case <-m.stopSignal:
				canceled = true
				cancel()
			}
		}()

		resp, err := completionProvider.CreateChatCompletionStream(
			ctx, requestParams, m.messages, replyHandler, m.replyChunkChan,
		)

		if err != nil && !canceled {
			return msgResponseError(err)
		}

		return msgResponseEnd(resp)
	}
}

func (m *model) persistConversation() tea.Cmd {
	existingMessages, err := m.ctx.Store.Messages(m.conversation)
	if err != nil {
		return wrapError(fmt.Errorf("Could not retrieve existing conversation messages while trying to save: %v", err))
	}

	existingById := make(map[uint]*models.Message, len(existingMessages))
	for _, msg := range existingMessages {
		existingById[msg.ID] = &msg
	}

	currentById := make(map[uint]*models.Message, len(m.messages))
	for _, msg := range m.messages {
		currentById[msg.ID] = &msg
	}

	for _, msg := range existingMessages {
		_, ok := currentById[msg.ID]
		if !ok {
			err := m.ctx.Store.DeleteMessage(&msg)
			if err != nil {
				return wrapError(fmt.Errorf("Failed to remove messages: %v", err))
			}
		}
	}

	for i, msg := range m.messages {
		if msg.ID > 0 {
			exist, ok := existingById[msg.ID]
			if ok {
				if msg.Content == exist.Content {
					continue
				}
				// update message when contents don't match that of store
				err := m.ctx.Store.UpdateMessage(&msg)
				if err != nil {
					return wrapError(err)
				}
			} else {
				// this would be quite odd... and I'm not sure how to handle
				// it at the time of writing this
			}
		} else {
			newMessage, err := m.ctx.Store.AddReply(m.conversation, msg)
			if err != nil {
				return wrapError(err)
			}
			m.setMessage(i, *newMessage)
		}
	}
	return nil
}

func (m *model) renderMessageHeading(i int, message *models.Message) string {
	icon := ""
	friendly := message.Role.FriendlyRole()
	style := lipgloss.NewStyle().Faint(true).Bold(true)

	switch message.Role {
	case models.MessageRoleSystem:
		icon = "⚙️"
	case models.MessageRoleUser:
		style = userStyle
	case models.MessageRoleAssistant:
		style = assistantStyle
	case models.MessageRoleToolCall:
		style = assistantStyle
		friendly = models.MessageRoleAssistant.FriendlyRole()
	case models.MessageRoleToolResult:
		icon = "🔧"
	}

	user := style.Render(icon + friendly)

	var prefix string
	var suffix string

	faint := lipgloss.NewStyle().Faint(true)
	if m.focus == focusMessages {
		if i == m.selectedMessage {
			prefix = "> "
		}
	}

	if message.ID == 0 {
		suffix += faint.Render(" (not saved)")
	}

	return headingStyle.Render(prefix + user + suffix)
}

func (m *model) renderMessage(msg *models.Message) string {
	sb := &strings.Builder{}
	sb.Grow(len(msg.Content) * 2)
	if msg.Content != "" {
		err := m.ctx.Chroma.Highlight(sb, msg.Content)
		if err != nil {
			sb.Reset()
			sb.WriteString(msg.Content)
		}
	}

	var toolString string
	switch msg.Role {
	case models.MessageRoleToolCall:
		bytes, err := yaml.Marshal(msg.ToolCalls)
		if err != nil {
			toolString = "Could not serialize ToolCalls"
		} else {
			toolString = "tool_calls:\n" + string(bytes)
		}
	case models.MessageRoleToolResult:
		if !m.showToolResults {
			break
		}

		type renderedResult struct {
			ToolName string `yaml:"tool"`
			Result   any
		}

		var toolResults []renderedResult
		for _, result := range msg.ToolResults {
			var jsonResult interface{}
			err := json.Unmarshal([]byte(result.Result), &jsonResult)
			if err != nil {
				// If parsing as JSON fails, treat Result as a plain string
				toolResults = append(toolResults, renderedResult{
					ToolName: result.ToolName,
					Result:   result.Result,
				})
			} else {
				// If parsing as JSON succeeds, marshal the parsed JSON into YAML
				toolResults = append(toolResults, renderedResult{
					ToolName: result.ToolName,
					Result:   &jsonResult,
				})
			}
		}

		bytes, err := yaml.Marshal(toolResults)
		if err != nil {
			toolString = "Could not serialize ToolResults"
		} else {
			toolString = "tool_results:\n" + string(bytes)
		}
	}

	if toolString != "" {
		toolString = strings.TrimRight(toolString, "\n")
		if msg.Content != "" {
			sb.WriteString("\n\n")
		}
		_ = m.ctx.Chroma.HighlightLang(sb, toolString, "yaml")
	}

	content := strings.TrimRight(sb.String(), "\n")

	if m.wrap {
		wrapWidth := m.content.Width - messageStyle.GetHorizontalPadding() - 2
		content = wordwrap.String(content, wrapWidth)
	}

	return messageStyle.Width(0).Render(content)
}

func (m *model) setMessages(messages []models.Message) {
	m.messages = messages
	m.rebuildMessageCache()
}

func (m *model) setMessage(i int, msg models.Message) {
	if i >= len(m.messages) {
		panic("i out of range")
	}
	m.messages[i] = msg
	m.messageCache[i] = m.renderMessage(&msg)
}

func (m *model) addMessage(msg models.Message) {
	m.messages = append(m.messages, msg)
	m.messageCache = append(m.messageCache, m.renderMessage(&msg))
}

func (m *model) setMessageContents(i int, content string) {
	if i >= len(m.messages) {
		panic("i out of range")
	}
	m.messages[i].Content = content
	m.messageCache[i] = m.renderMessage(&m.messages[i])
}

func (m *model) rebuildMessageCache() {
	m.messageCache = make([]string, len(m.messages))
	for i, msg := range m.messages {
		m.messageCache[i] = m.renderMessage(&msg)
	}
}

func (m *model) updateContent() {
	atBottom := m.content.AtBottom()
	m.content.SetContent(m.conversationView())
	if atBottom {
		// if we were at bottom before the update, scroll with the output
		m.content.GotoBottom()
	}
}

// render the conversation into a string
func (m *model) conversationView() string {
	sb := strings.Builder{}

	m.messageOffsets = make([]int, len(m.messages))
	lineCnt := 1
	for i, message := range m.messages {
		m.messageOffsets[i] = lineCnt

		switch message.Role {
		case models.MessageRoleToolCall:
			if !m.showToolResults && message.Content == "" {
				continue
			}
		case models.MessageRoleToolResult:
			if !m.showToolResults {
				continue
			}
		}

		heading := m.renderMessageHeading(i, &message)
		sb.WriteString(heading)
		sb.WriteString("\n")
		lineCnt += lipgloss.Height(heading)

		cached := m.messageCache[i]
		sb.WriteString(cached)
		sb.WriteString("\n")
		lineCnt += lipgloss.Height(cached)
	}

	return sb.String()
}

func Launch(ctx *lmcli.Context, convShortname string) error {
	p := tea.NewProgram(initialModel(ctx, convShortname), tea.WithAltScreen())
	if _, err := p.Run(); err != nil {
		return fmt.Errorf("Error running program: %v", err)
	}
	return nil
}