From 0b743464fbe5ce903f0f4559e71a3adbd78c118a Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 4 May 2024 09:45:57 +0530
Subject: [PATCH] Work on supporting mouse interactions via simple hyperlinks

---
 tools/cmd/list_fonts/main.go |  1 +
 tools/cmd/list_fonts/ui.go   |  6 +++
 tools/tui/mouse.go           | 76 ++++++++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+)

diff --git a/tools/cmd/list_fonts/main.go b/tools/cmd/list_fonts/main.go
index c6dc11891..fd9206500 100644
--- a/tools/cmd/list_fonts/main.go
+++ b/tools/cmd/list_fonts/main.go
@@ -70,6 +70,7 @@ func main() (rc int, err error) {
 		lp.SetCursorVisible(true)
 		return ``
 	}
+	lp.OnMouseEvent = h.on_mouse_event
 	lp.OnResize = func(_, _ loop.ScreenSize) error {
 		return h.draw_screen()
 	}
diff --git a/tools/cmd/list_fonts/ui.go b/tools/cmd/list_fonts/ui.go
index b0e422548..001b57866 100644
--- a/tools/cmd/list_fonts/ui.go
+++ b/tools/cmd/list_fonts/ui.go
@@ -5,6 +5,7 @@ import (
 	"strings"
 	"sync"
 
+	"kitty/tools/tui"
 	"kitty/tools/tui/loop"
 	"kitty/tools/tui/readline"
 	"kitty/tools/utils"
@@ -30,6 +31,7 @@ type handler struct {
 	state                State
 	err_mutex            sync.Mutex
 	err_in_worker_thread error
+	mouse_state          tui.MouseState
 
 	// Listing
 	rl                          *readline.Readline
@@ -278,6 +280,10 @@ func (h *handler) on_wakeup() (err error) {
 	return h.draw_screen()
 }
 
+func (h *handler) on_mouse_event(event *loop.MouseEvent) (err error) {
+	return h.mouse_state.UpdateState(event)
+}
+
 func (h *handler) on_key_event(event *loop.KeyEvent) (err error) {
 	if event.MatchesPressOrRepeat("ctrl+c") {
 		event.Handled = true
diff --git a/tools/tui/mouse.go b/tools/tui/mouse.go
index 41b894af3..2b414e7da 100644
--- a/tools/tui/mouse.go
+++ b/tools/tui/mouse.go
@@ -201,3 +201,79 @@ func (ms *MouseSelection) DragScroll(ev *loop.MouseEvent, lp *loop.Loop, callbac
 	}
 	ms.drag_scroll.mouse_event = *ev
 }
+
+type CellRegion struct {
+	TopLeft, BottomRight struct{ X, Y int }
+	Hovered              bool
+	Id                   string
+	OnClick              []func(id string) error
+}
+
+func (c CellRegion) Contains(x, y int) bool { // 0-based
+	if c.TopLeft.Y > y || c.BottomRight.Y < y {
+		return false
+	}
+	return (y > c.TopLeft.Y || (y == c.TopLeft.Y && x >= c.TopLeft.X)) && (y < c.BottomRight.Y || (y == c.BottomRight.Y && x <= c.BottomRight.X))
+}
+
+type MouseState struct {
+	Cell, Pixel struct{ X, Y int }
+	Pressed     struct{ Left, Right, Middle, Fourth, Fifth, Sixth, Seventh bool }
+
+	regions []*CellRegion
+}
+
+func (m *MouseState) AddCellRegion(id string, start_x, start_y, end_x, end_y int, on_click ...func(id string) error) *CellRegion {
+	cr := CellRegion{TopLeft: struct{ X, Y int }{start_x, start_y}, BottomRight: struct{ X, Y int }{end_x, end_y}, Id: id, OnClick: on_click}
+	m.regions = append(m.regions, &cr)
+	cr.Hovered = cr.Contains(m.Cell.X, m.Cell.Y)
+	return &cr
+}
+
+func (m *MouseState) ClearCellRegions() {
+	m.regions = nil
+}
+
+func (m *MouseState) UpdateState(ev *loop.MouseEvent) error {
+	m.Cell = ev.Cell
+	m.Pixel = ev.Pixel
+	if ev.Event_type == loop.MOUSE_PRESS || ev.Event_type == loop.MOUSE_RELEASE {
+		pressed := ev.Event_type == loop.MOUSE_PRESS
+		if ev.Buttons&loop.LEFT_MOUSE_BUTTON != 0 {
+			m.Pressed.Left = pressed
+		}
+		if ev.Buttons&loop.RIGHT_MOUSE_BUTTON != 0 {
+			m.Pressed.Right = pressed
+		}
+		if ev.Buttons&loop.MIDDLE_MOUSE_BUTTON != 0 {
+			m.Pressed.Middle = pressed
+		}
+		if ev.Buttons&loop.FOURTH_MOUSE_BUTTON != 0 {
+			m.Pressed.Fourth = pressed
+		}
+		if ev.Buttons&loop.FIFTH_MOUSE_BUTTON != 0 {
+			m.Pressed.Fifth = pressed
+		}
+		if ev.Buttons&loop.SIXTH_MOUSE_BUTTON != 0 {
+			m.Pressed.Sixth = pressed
+		}
+		if ev.Buttons&loop.SEVENTH_MOUSE_BUTTON != 0 {
+			m.Pressed.Seventh = pressed
+		}
+	}
+	for _, r := range m.regions {
+		if r.Contains(m.Cell.X, m.Cell.Y) {
+			r.Hovered = true
+			if ev.Event_type == loop.MOUSE_CLICK {
+				for _, f := range r.OnClick {
+					if err := f(r.Id); err != nil {
+						return err
+					}
+				}
+			}
+		} else {
+			r.Hovered = false
+		}
+	}
+	return nil
+}