init layout, notifications, tabs & more

Signed-off-by: Hadi <112569860+anotherhadi@users.noreply.github.com>

examples/layout/fullapp/router/router.go

@@ -0,0 +1,109 @@
+// Package router owns every page's own layout.Model for the lifetime of
+// the whole app, so switching pages never discards their state - only
+// which one is currently active/rendered changes. It slots into the root
+// tree's "router" leaf exactly like a single nested layout.Model would
+// (see examples/layout/nested), because Model implements layout.Navigable
+// itself on top of layout.Pane, delegating everything to whichever page is
+// active: ctrl+hjkl, the help bar, and SendMsg/RequestFocusMsg addressed to
+// ids inside that page all keep working transparently.
+package router
+
+import (
+	"charm.land/bubbles/v2/key"
+	tea "charm.land/bubbletea/v2"
+
+	"github.com/anotherhadi/ilovetui/examples/layout/fullapp/first"
+	"github.com/anotherhadi/ilovetui/examples/layout/fullapp/second"
+	"github.com/anotherhadi/ilovetui/examples/layout/fullapp/third"
+	"github.com/anotherhadi/ilovetui/layout"
+)
+
+// SelectMsg asks Model to switch its active page, by id ("first", "second"
+// or "third"). Sent by the sidebar via layout.SendMsg{Target: "router"} -
+// it never holds a reference to Model either.
+type SelectMsg struct{ Page string }
+
+type Model struct {
+	active string
+	pages  map[string]layout.Model
+}
+
+func New() *Model {
+	return &Model{
+		active: "first",
+		pages: map[string]layout.Model{
+			"first":  first.NewWorkspace(),
+			"second": second.NewWorkspace(),
+			"third":  third.NewWorkspace(),
+		},
+	}
+}
+
+func (m *Model) current() layout.Model { return m.pages[m.active] }
+
+func (m *Model) Init() tea.Cmd {
+	var cmds []tea.Cmd
+	for _, p := range m.pages {
+		if cmd := p.Init(); cmd != nil {
+			cmds = append(cmds, cmd)
+		}
+	}
+	return tea.Batch(cmds...)
+}
+
+func (m *Model) Update(msg tea.Msg) (layout.Pane, tea.Cmd) {
+	if sel, ok := msg.(SelectMsg); ok {
+		if _, exists := m.pages[sel.Page]; exists {
+			m.active = sel.Page
+		}
+		return m, nil
+	}
+
+	if size, ok := msg.(layout.SizeMsg); ok {
+		// Every page needs to stay correctly sized even while hidden - the
+		// outer tree only re-sends SizeMsg when the "router" leaf's own
+		// Rect changes, never on a plain page switch, so a page that was
+		// inactive during a resize must still learn about it here, or it
+		// renders at a stale size whenever it becomes active again.
+		var cmds []tea.Cmd
+		for id, p := range m.pages {
+			updated, cmd := p.Update(size)
+			m.pages[id] = updated.(layout.Model)
+			if cmd != nil {
+				cmds = append(cmds, cmd)
+			}
+		}
+		return m, tea.Batch(cmds...)
+	}
+
+	updated, cmd := m.current().Update(msg)
+	m.pages[m.active] = updated.(layout.Model)
+	return m, cmd
+}
+
+func (m *Model) View() string {
+	return m.current().View()
+}
+
+// Leaves, MoveFocus, Route, Focus and FocusedHelp implement
+// layout.Navigable, delegating to whichever page is currently active.
+
+func (m *Model) Leaves() []layout.LeafRect {
+	return m.current().Leaves()
+}
+
+func (m *Model) MoveFocus(dir layout.FocusDirection) bool {
+	return m.current().MoveFocus(dir)
+}
+
+func (m *Model) Route(target string, msg tea.Msg) (bool, tea.Cmd) {
+	return m.current().Route(target, msg)
+}
+
+func (m *Model) Focus(id string) (bool, tea.Cmd) {
+	return m.current().Focus(id)
+}
+
+func (m *Model) FocusedHelp() []key.Binding {
+	return m.current().FocusedHelp()
+}