T23c: AI chat, input

- PromptInput: attachments and context above the field, the owner's tools and
  send below; Enter sends, Shift-Enter breaks the line; / offers commands and
  @ offers context over forms::Suggestions; files dropped on it attach behind a
  drop veil
- AttachmentButton, AttachmentChip with thumbnails and uploads, ContextChips
- VoiceInputButton and VoiceWaveform with a red dot and the time
- ParameterPanel, SystemPromptEditor, TokenCounter, CostEstimator
- forms: a Newline action on Shift-Enter keeps one-line fields to one line;
  replace_trigger moves beside Suggestions; choose and dropped shared
- gallery: composer, pickers and tuning

src/forms/mention.rs

@@ -32,6 +32,20 @@ pub(crate) fn active_trigger(text: &str, caret: usize, triggers: &[char]) -> Opt
     (opens && word).then_some((ix, ch))
 }
 
+/// Replaces the trigger and its query, `at..caret`, with `text`, as one undo step.
+pub(crate) fn replace_trigger(
+    field: &Entity<TextInput>,
+    at: usize,
+    caret: usize,
+    text: &str,
+    cx: &mut App,
+) {
+    field.update(cx, |input, cx| {
+        input.select(at..caret, cx);
+        input.insert(text, cx);
+    });
+}
+
 /// The dismissed trigger, while it is still the one being typed.
 fn dismissal(dismissed: Option<usize>, active: Option<usize>) -> Option<usize> {
     dismissed.filter(|at| active == Some(*at))

src/forms/mod.rs

@@ -63,6 +63,7 @@ pub use date::{
     WeekPicker, YearPicker,
 };
 pub use expression::{ExpressionInput, evaluate, expression_highlights};
+pub(crate) use files::dropped;
 pub use files::{DropZone, FileInput};
 pub(crate) use glyphs::emoji_found;
 pub use glyphs::{EmojiPicker, IconPicker};
@@ -75,7 +76,7 @@ pub use knob::Knob;
 pub use listbox::ListBox;
 pub use masked::{COUNTRIES, MaskedInput, PhoneInput};
 pub use mention::{MentionInput, mention_highlights};
-pub(crate) use mention::{Suggestions, active_trigger, handles_matching};
+pub(crate) use mention::{Suggestions, active_trigger, handles_matching, replace_trigger};
 pub use multi::MultiSelect;
 pub use number::{NumberInput, ScrubInput};
 pub use options::Choice;
@@ -84,6 +85,7 @@ pub(crate) use options::{
 };
 pub use pairs::{FieldArray, KeyValueInput, ListInput};
 pub use path::PathInput;
+pub(crate) use path::choose;
 pub use pattern::{RegexInput, regex_highlights};
 pub use pin::PinInput;
 pub use radio::{Radio, RadioGroup};

src/forms/tests/mod.rs

@@ -299,3 +299,17 @@ fn a_range_gives_a_box_per_line_it_spans(cx: &mut TestAppContext) {
         "the second line starts at the edge"
     );
 }
+
+#[gpui::test]
+fn shift_enter_breaks_only_a_field_of_many_lines(cx: &mut TestAppContext) {
+    let (fields, cx) = open(1, false, cx);
+    focus(&fields[0], cx);
+    cx.simulate_input("one line");
+    cx.simulate_keystrokes("shift-enter");
+    cx.run_until_parked();
+    assert_eq!(
+        text(&fields[0], cx),
+        "one line",
+        "a single line stays single"
+    );
+}

src/forms/text/actions.rs

@@ -39,6 +39,7 @@ actions!(
         Undo,
         Redo,
         Enter,
+        Newline,
         Submit,
         ShowCharacterPalette,
     ]
@@ -84,6 +85,7 @@ pub(crate) fn bind_keys(cx: &mut App) {
         KeyBinding::new("secondary-z", Undo, Some(CONTEXT)),
         KeyBinding::new("secondary-shift-z", Redo, Some(CONTEXT)),
         KeyBinding::new("enter", Enter, Some(CONTEXT)),
+        KeyBinding::new("shift-enter", Newline, Some(CONTEXT)),
         KeyBinding::new("secondary-enter", Submit, Some(CONTEXT)),
     ];
     if cfg!(target_os = "macos") {
@@ -290,6 +292,12 @@ impl TextInput {
         }
     }
 
+    fn newline(&mut self, _: &Newline, _: &mut Window, cx: &mut Context<Self>) {
+        if self.rows.is_some() {
+            self.replace(self.selection.clone(), "\n", false, cx);
+        }
+    }
+
     fn submit(&mut self, _: &Submit, _: &mut Window, cx: &mut Context<Self>) {
         log::info!("text input: submitted");
         cx.emit(InputEvent::Submit);
@@ -380,6 +388,7 @@ impl Render for TextInput {
             .on_action(cx.listener(Self::undo))
             .on_action(cx.listener(Self::redo))
             .on_action(cx.listener(Self::enter))
+            .on_action(cx.listener(Self::newline))
             .on_action(cx.listener(Self::submit))
             .on_action(cx.listener(Self::show_character_palette))
             .on_mouse_down(MouseButton::Left, cx.listener(Self::mouse_down))