From d33b83e6ea5b52391c84393125ea778e1bb983fc Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 27 Mar 2023 17:56:00 +0530
Subject: [PATCH] More work on mouse selections

---
 gen-go-code.py        |  3 ++-
 kittens/diff/mouse.go | 61 +++++++++++++++++++++++++++++++++++++++++++
 kittens/diff/ui.go    | 26 +++++++++++-------
 3 files changed, 79 insertions(+), 11 deletions(-)
 create mode 100644 kittens/diff/mouse.go

diff --git a/gen-go-code.py b/gen-go-code.py
index 5385e132e..76218c42d 100755
--- a/gen-go-code.py
+++ b/gen-go-code.py
@@ -506,10 +506,11 @@ var DocTitleMap = map[string]string{serialize_go_dict(ref_map['doc'])}
 var AllowedShellIntegrationValues = []string{{ {str(sorted(allowed_shell_integration_values))[1:-1].replace("'", '"')} }}
 var KittyConfigDefaults = struct {{
 Term, Shell_integration, Select_by_word_characters string
+Wheel_scroll_multiplier int
 Url_prefixes []string
 }}{{
 Term: "{Options.term}", Shell_integration: "{' '.join(Options.shell_integration)}", Url_prefixes: []string{{ {url_prefixes} }},
-Select_by_word_characters: `{Options.select_by_word_characters}`,
+Select_by_word_characters: `{Options.select_by_word_characters}`, Wheel_scroll_multiplier: {Options.wheel_scroll_multiplier},
 }}
 '''  # }}}
 
diff --git a/kittens/diff/mouse.go b/kittens/diff/mouse.go
new file mode 100644
index 000000000..ae96b049c
--- /dev/null
+++ b/kittens/diff/mouse.go
@@ -0,0 +1,61 @@
+// License: GPLv3 Copyright: 2023, Kovid Goyal, <kovid at kovidgoyal.net>
+
+package diff
+
+import (
+	"fmt"
+	"kitty"
+	"kitty/tools/config"
+	"kitty/tools/tui/loop"
+	"kitty/tools/utils"
+	"path/filepath"
+	"strconv"
+)
+
+var _ = fmt.Print
+
+type MouseSelection struct {
+	start_line, end_line ScrollPos
+}
+
+type KittyOpts struct {
+	Wheel_scroll_multiplier int
+}
+
+func read_relevant_kitty_opts(path string) KittyOpts {
+	ans := KittyOpts{Wheel_scroll_multiplier: kitty.KittyConfigDefaults.Wheel_scroll_multiplier}
+	handle_line := func(key, val string) error {
+		switch key {
+		case "wheel_scroll_multiplier":
+			v, err := strconv.Atoi(val)
+			if err == nil {
+				ans.Wheel_scroll_multiplier = v
+			}
+		}
+		return nil
+	}
+	cp := config.ConfigParser{LineHandler: handle_line}
+	cp.ParseFiles(path)
+	return ans
+}
+
+var RelevantKittyOpts = (&utils.Once[KittyOpts]{Run: func() KittyOpts {
+	return read_relevant_kitty_opts(filepath.Join(utils.ConfigDir(), "kitty.conf"))
+}}).Get
+
+func (self *Handler) handle_wheel_event(up bool) {
+	amt := RelevantKittyOpts().Wheel_scroll_multiplier
+	if up {
+		amt *= -1
+	}
+	self.dispatch_action(`scroll_by`, strconv.Itoa(amt))
+}
+
+func (self *Handler) start_mouse_selection(ev *loop.MouseEvent) {
+}
+
+func (self *Handler) update_mouse_selection(ev *loop.MouseEvent) {
+}
+
+func (self *Handler) finish_mouse_selection(ev *loop.MouseEvent) {
+}
diff --git a/kittens/diff/ui.go b/kittens/diff/ui.go
index 83715a082..3f2b30ded 100644
--- a/kittens/diff/ui.go
+++ b/kittens/diff/ui.go
@@ -54,6 +54,7 @@ var image_collection *graphics.ImageCollection
 type screen_size struct{ rows, columns, num_lines, cell_width, cell_height int }
 type Handler struct {
 	async_results                                       chan AsyncResult
+	mouse_selection                                     MouseSelection
 	shortcut_tracker                                    config.ShortcutTracker
 	left, right                                         string
 	collection                                          *Collection
@@ -628,20 +629,25 @@ func (self *Handler) dispatch_action(name, args string) error {
 	return nil
 }
 
-func (self *Handler) handle_wheel_event(up bool) {
-	if self.logical_lines != nil {
-		amt := 2
-		if up {
-			amt *= -1
-		}
-		self.dispatch_action(`scroll_by`, strconv.Itoa(amt))
-	}
-}
-
 func (self *Handler) on_mouse_event(ev *loop.MouseEvent) error {
+	if self.logical_lines == nil {
+		return nil
+	}
 	if ev.Event_type == loop.MOUSE_PRESS && ev.Buttons&(loop.MOUSE_WHEEL_UP|loop.MOUSE_WHEEL_DOWN) != 0 {
 		self.handle_wheel_event(ev.Buttons&(loop.MOUSE_WHEEL_UP) != 0)
 		return nil
 	}
+	if ev.Event_type == loop.MOUSE_PRESS && ev.Buttons&loop.LEFT_MOUSE_BUTTON != 0 {
+		self.start_mouse_selection(ev)
+		return nil
+	}
+	if ev.Event_type == loop.MOUSE_MOVE {
+		self.update_mouse_selection(ev)
+		return nil
+	}
+	if ev.Event_type == loop.MOUSE_RELEASE && ev.Buttons&loop.LEFT_MOUSE_BUTTON != 0 {
+		self.finish_mouse_selection(ev)
+		return nil
+	}
 	return nil
 }