Refactor TUI rendering handling and general cleanup

Improves render handling by moving the responsibility of laying out the
whole UI from each view and into the main `tui` model. Our `ViewModel`
interface has now diverged from bubbletea's `Model` and introduces
individual `Header`, `Content`, and `Footer` methods for rendering those
UI elements.

Also moved away from using value receivers on our Update and View
functions (as is common across Bubbletea) to pointer receivers, which
cleaned up some of the weirder aspects of the code (e.g. before we
essentially had no choice but to do our rendering in `Update` in order
to calculate and update the final height of the main content's
`viewport`).

pkg/tui/views/chat/chat.go

@@ -5,7 +5,6 @@ import (
 
 	"git.mlow.ca/mlow/lmcli/pkg/api"
 	"git.mlow.ca/mlow/lmcli/pkg/tui/model"
-	"git.mlow.ca/mlow/lmcli/pkg/tui/shared"
 	"github.com/charmbracelet/bubbles/cursor"
 	"github.com/charmbracelet/bubbles/spinner"
 	"github.com/charmbracelet/bubbles/textarea"
@@ -72,11 +71,10 @@ const (
 )
 
 type Model struct {
-	*shared.ViewState
-	shared.Sections
-
 	// App state
 	App		*model.AppModel
+	Height int
+	Width int
 
 	// Chat view state
 	state           state // current overall status of the view
@@ -106,14 +104,9 @@ type Model struct {
 	elapsed    time.Duration
 }
 
-func (m Model) Initialized() bool {
-	return m.ViewState.Initialized
-}
-
-func Chat(app *model.AppModel, shared shared.ViewState) shared.ViewModel {
+func Chat(app *model.AppModel) *Model {
 	m := Model{
 		App: app,
-		ViewState: &shared,
 
 		state:        idle,
 		persistence:  true,
@@ -166,12 +159,10 @@ func Chat(app *model.AppModel, shared shared.ViewState) shared.ViewModel {
 	m.input.FocusedStyle.CursorLine = lipgloss.NewStyle()
 	m.input.FocusedStyle.Base = inputFocusedStyle
 	m.input.BlurredStyle.Base = inputBlurredStyle
-
-	return m
+	return &m
 }
 
-func (m Model) Init() tea.Cmd {
-	m.ViewState.Initialized = true
+func (m *Model) Init() tea.Cmd {
 	return tea.Batch(
 		m.waitForResponseChunk(),
 	)

pkg/tui/views/chat/update.go

@@ -47,7 +47,7 @@ func (m *Model) updateContent() {
 	}
 }
 
-func (m Model) Update(msg tea.Msg) (shared.ViewModel, tea.Cmd) {
+func (m *Model) Update(msg tea.Msg) (shared.ViewModel, tea.Cmd) {
 	inputHandled := false
 
 	var cmds []tea.Cmd
@@ -169,8 +169,8 @@ func (m Model) Update(msg tea.Msg) (shared.ViewModel, tea.Cmd) {
 		m.updateContent()
 	case msgChatResponseError:
 		m.state = idle
-		m.ViewState.Err = error(msg)
 		m.updateContent()
+		return m, shared.WrapError(msg)
 	case msgToolResults:
 		last := len(m.App.Messages) - 1
 		if last < 0 {
@@ -249,24 +249,6 @@ func (m Model) Update(msg tea.Msg) (shared.ViewModel, tea.Cmd) {
 		}
 	}
 
-	// update views once window dimensions are known
-	if m.Width > 0 {
-		m.Header = m.headerView()
-		m.Footer = m.footerView()
-		m.Error = tuiutil.ErrorBanner(m.Err, m.Width)
-		fixedHeight := tuiutil.Height(m.Header) + tuiutil.Height(m.Error) + tuiutil.Height(m.Footer)
-
-		// calculate clamped input height to accomodate input text
-		// minimum 4 lines, maximum half of content area
-		newHeight := max(4, min((m.Height-fixedHeight-1)/2, m.input.LineCount()))
-		m.input.SetHeight(newHeight)
-		m.Input = m.input.View()
-
-		// remaining height towards content
-		m.content.Height = m.Height - fixedHeight - tuiutil.Height(m.Input)
-		m.Content = m.content.View()
-	}
-
 	// 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

pkg/tui/views/chat/view.go

@@ -39,29 +39,6 @@ var (
 	footerStyle = lipgloss.NewStyle()
 )
 
-func (m Model) View() string {
-	if m.Width == 0 {
-		return ""
-	}
-	sections := make([]string, 0, 6)
-
-	if m.Header != "" {
-		sections = append(sections, m.Header)
-	}
-
-	sections = append(sections, m.Content)
-	if m.Error != "" {
-		sections = append(sections, m.Error)
-	}
-	sections = append(sections, m.Input)
-
-	if m.Footer != "" {
-		sections = append(sections, m.Footer)
-	}
-
-	return lipgloss.JoinVertical(lipgloss.Left, sections...)
-}
-
 func (m *Model) renderMessageHeading(i int, message *api.Message) string {
 	icon := ""
 	friendly := message.Role.FriendlyRole()
@@ -254,7 +231,20 @@ func (m *Model) conversationMessagesView() string {
 	return sb.String()
 }
 
-func (m *Model) headerView() string {
+func (m *Model) Content(width, height int) string {
+	// calculate clamped input height to accomodate input text
+	// minimum 4 lines, maximum half of content area
+	inputHeight := max(4, min(height/2, m.input.LineCount()))
+	m.input.SetHeight(inputHeight)
+	input := m.input.View()
+
+	// remaining height towards content
+	m.content.Width, m.content.Height = width, height - tuiutil.Height(input)
+	content := m.content.View()
+	return lipgloss.JoinVertical(lipgloss.Left, content, input)
+}
+
+func (m *Model) Header(width int) string {
 	titleStyle := lipgloss.NewStyle().Bold(true)
 	var title string
 	if m.App.Conversation != nil && m.App.Conversation.Title != "" {
@@ -262,12 +252,12 @@ func (m *Model) headerView() string {
 	} else {
 		title = "Untitled"
 	}
-	title = tuiutil.TruncateToCellWidth(title, m.Width-styles.Header.GetHorizontalPadding(), "...")
+	title = tuiutil.TruncateToCellWidth(title, width-styles.Header.GetHorizontalPadding(), "...")
 	header := titleStyle.Render(title)
-	return styles.Header.Width(m.Width).Render(header)
+	return styles.Header.Width(width).Render(header)
 }
 
-func (m *Model) footerView() string {
+func (m *Model) Footer(width int) string {
 	segmentStyle := lipgloss.NewStyle().PaddingLeft(1).PaddingRight(1).Faint(true)
 	segmentSeparator := "|"
 
@@ -305,7 +295,7 @@ func (m *Model) footerView() string {
 	right := strings.Join(rightSegments, segmentSeparator)
 
 	totalWidth := lipgloss.Width(left) + lipgloss.Width(right)
-	remaining := m.Width - totalWidth
+	remaining := width - totalWidth
 
 	var padding string
 	if remaining > 0 {
@@ -314,7 +304,7 @@ func (m *Model) footerView() string {
 
 	footer := left + padding + right
 	if remaining < 0 {
-		footer = tuiutil.TruncateToCellWidth(footer, m.Width, "...")
+		footer = tuiutil.TruncateToCellWidth(footer, width, "...")
 	}
-	return footerStyle.Width(m.Width).Render(footer)
+	return footerStyle.Width(width).Render(footer)
 }