feat(tui): add bubbletea terminal UI with entity list, detail, and capture

Adds `nib tui` command and `make tui` target. Scrollable entity list
with j/k navigation, enter for detail view, `a` to capture new entries
using the existing parse grammar, and `d` to delete.

internal/tui/model.go

@@ -0,0 +1,176 @@
+package tui
+
+import (
+	tea "github.com/charmbracelet/bubbletea"
+
+	"github.com/lerko/nib/internal/db"
+)
+
+type viewState int
+
+const (
+	stateList viewState = iota
+	stateDetail
+	stateInput
+)
+
+type model struct {
+	store  *db.Store
+	state  viewState
+	width  int
+	height int
+
+	list   listModel
+	detail detailModel
+	input  inputModel
+
+	status string
+	err    error
+}
+
+func newModel(store *db.Store) model {
+	return model{
+		store:  store,
+		state:  stateList,
+		list:   newListModel(),
+		detail: newDetailModel(),
+		input:  newInputModel(),
+	}
+}
+
+func (m model) Init() tea.Cmd {
+	return loadEntities(m.store, db.DefaultListParams())
+}
+
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	switch msg := msg.(type) {
+	case tea.WindowSizeMsg:
+		m.width = msg.Width
+		m.height = msg.Height
+		m.list.setSize(m.width, m.contentHeight())
+		m.detail.setSize(m.width, m.contentHeight())
+		return m, nil
+
+	case entitiesLoadedMsg:
+		m.list.setEntities(msg.entities)
+		m.status = ""
+		m.err = nil
+		return m, nil
+
+	case entityCreatedMsg:
+		m.state = stateList
+		m.input.reset()
+		m.status = "created"
+		return m, loadEntities(m.store, db.DefaultListParams())
+
+	case entityDeletedMsg:
+		m.status = "deleted"
+		return m, loadEntities(m.store, db.DefaultListParams())
+
+	case errMsg:
+		m.err = msg.err
+		return m, nil
+
+	case tea.KeyMsg:
+		if m.state == stateInput {
+			return m.updateInput(msg)
+		}
+		return m.updateKeys(msg)
+	}
+
+	return m, nil
+}
+
+func (m model) updateKeys(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
+	switch {
+	case msg.String() == "q" || msg.String() == "ctrl+c":
+		return m, tea.Quit
+
+	case msg.String() == "a" && m.state == stateList:
+		m.state = stateInput
+		m.input.focus()
+		return m, m.input.ti.Focus()
+
+	case msg.String() == "esc":
+		if m.state == stateDetail {
+			m.state = stateList
+		}
+		return m, nil
+
+	case msg.String() == "enter" && m.state == stateList:
+		if e := m.list.selected(); e != nil {
+			m.detail.setEntity(e)
+			m.state = stateDetail
+		}
+		return m, nil
+
+	case msg.String() == "d" && m.state == stateList:
+		if e := m.list.selected(); e != nil {
+			return m, deleteEntity(m.store, e.ID)
+		}
+		return m, nil
+	}
+
+	switch m.state {
+	case stateList:
+		m.list = m.list.update(msg)
+	case stateDetail:
+		m.detail = m.detail.update(msg)
+	}
+	return m, nil
+}
+
+func (m model) updateInput(msg tea.KeyMsg) (tea.Model, tea.Cmd) {
+	switch msg.String() {
+	case "esc":
+		m.state = stateList
+		m.input.reset()
+		return m, nil
+	case "enter":
+		if e := m.input.submit(); e != nil {
+			return m, createEntity(m.store, e)
+		}
+		return m, nil
+	}
+
+	m.input = m.input.updateKey(msg)
+	return m, nil
+}
+
+func (m model) View() string {
+	var content string
+
+	switch m.state {
+	case stateList:
+		content = m.list.view(m.width)
+	case stateDetail:
+		content = m.detail.view(m.width)
+	case stateInput:
+		content = m.list.view(m.width)
+	}
+
+	header := titleStyle.Render("nib")
+	footer := m.footerView()
+
+	return header + "\n" + content + "\n" + footer
+}
+
+func (m model) footerView() string {
+	if m.state == stateInput {
+		return m.input.view(m.width)
+	}
+
+	if m.err != nil {
+		return errorStyle.Render("error: " + m.err.Error())
+	}
+
+	if m.status != "" {
+		return statusStyle.Render(m.status)
+	}
+
+	return helpStyle.Render("a:add  enter:view  d:delete  q:quit  ?:help")
+}
+
+func (m model) contentHeight() int {
+	return m.height - 3
+}