more diagnostics

13 files changed, 241 insertions, 48 deletions

diff --git a/buffer.c b/buffer.c
index 1d8effd..8d48c6d 100644
--- a/buffer.c
+++ b/buffer.c
@@ -28,6 +28,14 @@ struct BufferEdit {
 	double time; // time at start of edit (i.e. the time just before the edit), in seconds since epoch
 };
 
+typedef struct {
+	MessageType severity;
+	BufferPos pos;
+	char *message;
+	// may be NULL
+	char *url;
+} Diagnostic;
+
 struct TextBuffer {
 	/// NULL if this buffer is untitled or doesn't correspond to a file (e.g. line buffers)
 	char *path;
@@ -98,6 +106,8 @@ struct TextBuffer {
 	/// see \ref frame_earliest_line_modified.
 	u32 frame_latest_line_modified;
 
+	Diagnostic *diagnostics;
+
 	/// lines
 	Line *lines;
 	/// last error
@@ -974,6 +984,19 @@ static void buffer_line_free(Line *line) {
 	free(line->str);
 }
 
+static void diagnostic_free(Diagnostic *diagnostic) {
+	free(diagnostic->message);
+	free(diagnostic->url);
+	memset(diagnostic, 0, sizeof *diagnostic);
+}
+
+static void buffer_diagnostics_clear(TextBuffer *buffer) {
+	arr_foreach_ptr(buffer->diagnostics, Diagnostic, d) {
+		diagnostic_free(d);
+	}
+	arr_clear(buffer->diagnostics);
+}
+
 static void buffer_free_inner(TextBuffer *buffer) {
 	Ted *ted = buffer->ted;
 	if (!ted->quit) { // don't send didClose on quit (calling buffer_lsp would actually create a LSP if this is called after destroying all the LSPs which isnt good)
@@ -995,7 +1018,7 @@ static void buffer_free_inner(TextBuffer *buffer) {
 		buffer_edit_free(edit);
 	arr_foreach_ptr(buffer->redo_history, BufferEdit, edit)
 		buffer_edit_free(edit);
-
+	buffer_diagnostics_clear(buffer);
 	arr_free(buffer->undo_history);
 	arr_free(buffer->redo_history);
 	memset(buffer, 0, sizeof *buffer);
@@ -1386,6 +1409,24 @@ i64 buffer_pos_move_down(TextBuffer *buffer, BufferPos *pos, i64 by) {
 	return +buffer_pos_move_vertically(buffer, pos, +by);
 }
 
+bool buffer_pos_move_according_to_edit(BufferPos *pos, const EditInfo *edit) {
+	if (buffer_pos_cmp(*pos, edit->pos) <= 0)
+		return true;
+	if (edit->chars_inserted) {
+		if (edit->pos.line == pos->line) {
+			pos->index += edit->end.index - edit->pos.index;
+		}
+		pos->line += edit->end.line - edit->pos.line;
+	} else {
+		if (buffer_pos_cmp(*pos, edit->end) < 0)
+			return false;
+		if (pos->line == edit->end.line)
+			pos->index += edit->pos.index - edit->end.index;
+		pos->line -= edit->end.line - edit->pos.line;
+	}
+	return true;
+}
+
 static bool buffer_line_is_blank(Line *line) {
 	for (u32 i = 0; i < line->len; ++i)
 		if (!is32_space(line->str[i]))
@@ -1947,11 +1988,14 @@ BufferPos buffer_insert_text_at_pos(TextBuffer *buffer, BufferPos pos, String32
 	
 	const EditInfo info = {
 		.pos = pos,
+		.end = b,
 		.chars_deleted = 0,
-		.newlines_deleted = 0,
 		.chars_inserted = insertion_len,
-		.newlines_inserted = n_added_lines,
 	};
+	// move diagnostics around as needed
+	arr_foreach_ptr(buffer->diagnostics, Diagnostic, d) {
+		buffer_pos_move_according_to_edit(&d->pos, &info);
+	}
 	
 	signature_help_retrigger(buffer->ted);
 	arr_foreach_ptr(buffer->ted->edit_notifys, EditNotifyInfo, n) {
@@ -2424,8 +2468,8 @@ void buffer_delete_chars_at_pos(TextBuffer *buffer, BufferPos pos, i64 nchars_)
 	u32 line_idx = pos.line;
 	u32 index = pos.index;
 	Line *line = &buffer->lines[line_idx], *lines_end = &buffer->lines[buffer->nlines];
-	u32 newlines_deleted = 0;
-	
+	const BufferPos end_pos = buffer_pos_advance(buffer, pos, nchars);
+
 	if (nchars + index > line->len) {
 		// delete rest of line
 		nchars -= line->len - index + 1; // +1 for the newline that got deleted
@@ -2440,7 +2484,6 @@ void buffer_delete_chars_at_pos(TextBuffer *buffer, BufferPos pos, i64 nchars_)
 			// delete everything to the end of the file
 			for (u32 idx = line_idx + 1; idx < buffer->nlines; ++idx) {
 				buffer_line_free(&buffer->lines[idx]);
-				++newlines_deleted;
 			}
 			buffer_shorten(buffer, line_idx + 1);
 		} else {
@@ -2453,7 +2496,7 @@ void buffer_delete_chars_at_pos(TextBuffer *buffer, BufferPos pos, i64 nchars_)
 			// remove all lines between line + 1 and last_line (inclusive).
 			buffer_delete_lines(buffer, line_idx + 1, (u32)(last_line - line));
 
-			newlines_deleted = (u32)(last_line - line);
+			const u32 newlines_deleted = (u32)(last_line - line);
 			buffer_shorten(buffer, buffer->nlines - newlines_deleted);
 		}
 	} else {
@@ -2474,11 +2517,14 @@ void buffer_delete_chars_at_pos(TextBuffer *buffer, BufferPos pos, i64 nchars_)
 	
 	const EditInfo info = {
 		.pos = pos,
+		.end = end_pos,
 		.chars_inserted = 0,
-		.newlines_inserted = 0,
 		.chars_deleted = deletion_len,
-		.newlines_deleted = newlines_deleted,
 	};
+	// move diagnostics around as needed
+	arr_foreach_ptr(buffer->diagnostics, Diagnostic, d) {
+		buffer_pos_move_according_to_edit(&d->pos, &info);
+	}
 	arr_foreach_ptr(buffer->ted->edit_notifys, EditNotifyInfo, n) {
 		n->fn(n->context, buffer, &info);
 	}
@@ -3268,9 +3314,10 @@ void buffer_render(TextBuffer *buffer, Rect r) {
 	
 	float render_start_y = y1 - (float)(buffer->scroll_y - start_line) * char_height; // where the 1st line is rendered
 
-
+	const Diagnostic *hover_diagnostic = NULL;
 	// line numbering
 	if (!buffer->is_line_buffer && settings->line_numbers) {
+		const Diagnostic *diagnostic = arr_len(buffer->diagnostics) ? buffer->diagnostics : NULL;
 		float max_digit_width = 0;
 		for (char32_t digit = '0'; digit <= '9'; ++digit) {
 			max_digit_width = maxf(max_digit_width, text_font_char_width(font, digit));
@@ -3285,23 +3332,56 @@ void buffer_render(TextBuffer *buffer, Rect r) {
 		text_state.max_y = y2;
 
 		float y = render_start_y;
-		u32 cursor_line = buffer->cursor_pos.line;
+		const u32 cursor_line = buffer->cursor_pos.line;
+		const float diagnostic_x2 = x1 + line_number_width + 2;
 		for (u32 line = start_line; line < nlines; ++line) {
 			char str[32] = {0};
 			strbuf_printf(str, "%" PRIu32, line + 1); // convert line number to string
-			float x = x1 + line_number_width - text_get_size_vec2(font, str).x; // right justify
+			const float x = x1 + line_number_width - text_get_size_vec2(font, str).x; // right justify
+			u32 line_number_color = settings_color(settings, line == cursor_line ? COLOR_CURSOR_LINE_NUMBER : COLOR_LINE_NUMBERS);
+			if (diagnostic) {
+				while (diagnostic->pos.line < line) {
+					++diagnostic;
+					if (diagnostic == buffer->diagnostics + arr_len(buffer->diagnostics)) {
+						diagnostic = NULL;
+						break;
+					}
+				}
+			}
+			if (diagnostic && diagnostic->pos.line == line) {
+				// show diagnostic
+				ColorSetting color_setting=0;
+				ted_color_settings_for_message_type(diagnostic->severity, NULL, &color_setting);
+				u32 color = settings_color(settings, color_setting) | 0xff;
+				u32 alt_line_number_color = line == cursor_line ? 0xffffffff : 0x000000ff;
+				if (color_contrast_ratio_u32(color, line_number_color)
+					< color_contrast_ratio_u32(color, alt_line_number_color)) {
+					// change color so that line number is still visible
+					line_number_color = alt_line_number_color;
+				}
+				const Rect rect = rect4(x1, y, diagnostic_x2, y + char_height);
+				gl_geometry_rect(
+					rect,
+					color & 0xffffff7f
+				);
+				if (ted_mouse_in_rect(ted, rect)) {
+					hover_diagnostic = diagnostic;
+					if (diagnostic->url && ted_clicked_in_rect(ted, rect))
+						open_with_default_application(diagnostic->url);
+					ted->cursor = ted->cursor_hand;
+				}
+			}
 			// set color
-			settings_color_floats(settings, line == cursor_line ? COLOR_CURSOR_LINE_NUMBER : COLOR_LINE_NUMBERS,
-				text_state.color);
+			rgba_u32_to_floats(line_number_color, text_state.color);
 			text_state.x = x; text_state.y = y;
 			text_state_break_kerning(&text_state);
 			text_utf8_with_state(font, &text_state, str);
 			y += char_height;
+			
 			if (y > y2) break;
 		}
 
-		x1 += line_number_width;
-		x1 += 2; // a little bit of padding
+		x1 = diagnostic_x2;
 		// line separating line numbers from text
 		gl_geometry_rect(rect_xywh(x1, y1, border_thickness, y2 - y1), settings_color(settings, COLOR_LINE_NUMBERS_SEPARATOR));
 		x1 += border_thickness;
@@ -3321,7 +3401,7 @@ void buffer_render(TextBuffer *buffer, Rect r) {
 	}
 
 	// change cursor to ibeam when it's hovering over the buffer
-	if ((!menu_is_any_open(ted) || buffer == ted->line_buffer) && rect_contains_point(rect4(x1, y1, x2, y2), ted->mouse_pos)) {
+	if ((!menu_is_any_open(ted) || buffer == ted->line_buffer) && ted_mouse_in_rect(ted, rect4(x1, y1, x2, y2))) {
 		ted->cursor = ted->cursor_ibeam;
 	}
 
@@ -3331,7 +3411,7 @@ void buffer_render(TextBuffer *buffer, Rect r) {
 		buffer->center_cursor_next_frame = false;
 	}
 
-	if (rect_contains_point(rect4(x1, y1, x2, y2), ted->mouse_pos) && !menu_is_any_open(ted)) {
+	if (ted_mouse_in_rect(ted, rect4(x1, y1, x2, y2)) && !menu_is_any_open(ted)) {
 		// scroll with mouse wheel
 		double scroll_speed = 2.5;
 		buffer_scroll(buffer, ted->scroll_total_x * scroll_speed, ted->scroll_total_y * scroll_speed);
@@ -3521,6 +3601,8 @@ void buffer_render(TextBuffer *buffer, Rect r) {
 		}
 		gl_geometry_draw();
 	}
+	
+	//TODO(hover_diagnostic);
 
 }
 
@@ -3745,3 +3827,53 @@ void buffer_highlight_lsp_range(TextBuffer *buffer, LSPRange range, ColorSetting
 		gl_geometry_rect(r2, settings_color(settings, COLOR_HOVER_HL));
 	}
 }
+
+static MessageType diagnostic_severity(const LSPDiagnostic *diagnostic) {
+	switch (diagnostic->severity) {
+	case LSP_DIAGNOSTIC_SEVERITY_ERROR:
+		return MESSAGE_ERROR;
+	case LSP_DIAGNOSTIC_SEVERITY_WARNING:
+		return MESSAGE_WARNING;
+	case LSP_DIAGNOSTIC_SEVERITY_INFORMATION:
+	case LSP_DIAGNOSTIC_SEVERITY_HINT:
+		return MESSAGE_INFO;
+	}
+	assert(0);
+	return MESSAGE_INFO;
+}
+
+static int diagnostic_cmp(const void *av, const void *bv) {
+	const Diagnostic *a = av, *b = bv;
+	// first sort by line
+	if (a->pos.line < b->pos.line) return -1;
+	if (a->pos.line > b->pos.line) return 1;
+
+	// then put higher severity diagnostics first
+	if (a->severity < b->severity) return 1;
+	if (a->severity > b->severity) return -1;
+
+	return 0;
+}
+
+void buffer_publish_diagnostics(TextBuffer *buffer, const LSPRequest *request, LSPDiagnostic *diagnostics) {
+	buffer_diagnostics_clear(buffer);
+	arr_foreach_ptr(diagnostics, const LSPDiagnostic, diagnostic) {
+		Diagnostic *d = arr_addp(buffer->diagnostics);
+		d->pos = buffer_pos_from_lsp(buffer, diagnostic->range.start);
+		d->severity = diagnostic_severity(diagnostic);
+		char message[280];
+		const char *code = lsp_request_string(request, diagnostic->code);
+		if (*code) {
+			str_printf(message, sizeof message - 4, "[%s] %s", code,
+				lsp_request_string(request, diagnostic->message));
+		} else {
+			str_cpy(message, sizeof message - 4,
+				lsp_request_string(request, diagnostic->message));
+		}
+		strcpy(&message[sizeof message - 4], "...");
+		d->message = str_dup(message);
+		const char *url = lsp_request_string(request, diagnostic->code_description_uri);
+		d->url = *url ? str_dup(url) : NULL;
+	}
+	arr_qsort(buffer->diagnostics, diagnostic_cmp);
+}
diff --git a/colors.c b/colors.c
index 3e704e9..d9ef7aa 100644
--- a/colors.c
+++ b/colors.c
@@ -169,3 +169,33 @@ u32 color_apply_opacity(u32 color, float opacity) {
 	opacity = clampf(opacity, 0.0f, 1.0f);
 	return (color & 0xffffff00) | (u32)((color & 0xff) * opacity);
 }
+
+
+static float color_relative_luminance(const float rgb[3]) {
+	// see https://www.w3.org/TR/2008/REC-WCAG20-20081211/#relativeluminancedef
+	float c[3];
+	for (int i = 0; i < 3; ++i) {
+		const float x = rgb[i];
+		c[i] = x <= 0.03928f ? x * (1.0f / 12.92f) : powf((x + 0.055f) * (1.0f / 1.055f), 2.4f);
+	}
+	return 0.2126f * c[0] + 0.7152f * c[1] + 0.0722f * c[2];
+}
+
+float color_contrast_ratio(const float rgb1[3], const float rgb2[3]) {
+	// see https://www.w3.org/TR/2008/REC-WCAG20-20081211/#contrast-ratiodef
+	float l1 = color_relative_luminance(rgb1);
+	float l2 = color_relative_luminance(rgb2);
+	if (l1 < l2) {
+		float temp = l1;
+		l1 = l2;
+		l2 = temp;
+	}
+	return (l1 + 0.05f) / (l2 + 0.05f);
+}
+
+float color_contrast_ratio_u32(u32 color1, u32 color2) {
+	float rgb1[4], rgb2[4];
+	rgba_u32_to_floats(color1, rgb1);
+	rgba_u32_to_floats(color2, rgb2);
+	return color_contrast_ratio(rgb1, rgb2);
+}
diff --git a/find.c b/find.c
index f5fd9ce..b5fee08 100644
--- a/find.c
+++ b/find.c
@@ -538,7 +538,7 @@ static void find_edit_notify(void *context, TextBuffer *buffer, const EditInfo *
 		const u32 line = info->pos.line;
 		
 		if (info->chars_inserted) {
-			const u32 newlines_inserted = info->newlines_inserted;
+			const u32 newlines_inserted = info->end.line - info->pos.line;
 			
 			if (newlines_inserted) {
 				// update line numbers for find results after insertion.
@@ -553,7 +553,7 @@ static void find_edit_notify(void *context, TextBuffer *buffer, const EditInfo *
 			find_research_lines(ted, line, line + newlines_inserted);
 			
 		} else if (info->chars_deleted) {
-			const u32 newlines_deleted = info->newlines_deleted;
+			const u32 newlines_deleted = info->end.line - info->pos.line;
 			
 			if (newlines_deleted) {
 				// update line numbers for find results after deletion.
diff --git a/ide-autocomplete.c b/ide-autocomplete.c
index 6f67506..295dcda 100644
--- a/ide-autocomplete.c
+++ b/ide-autocomplete.c
@@ -616,7 +616,7 @@ void autocomplete_frame(Ted *ted) {
 		ac->rect = menu_rect;
 	}
 	
-	i32 mouse_entry = scroll + (i32)((ted->mouse_pos.y - start_y) / char_height);
+	i32 mouse_entry = scroll + (i32)((ted_mouse_pos(ted).y - start_y) / char_height);
 	
 	Autocompletion *document = NULL;
 	if (ncompletions) {
@@ -629,7 +629,7 @@ void autocomplete_frame(Ted *ted) {
 		}
 	}
 	if (mouse_entry >= 0 && mouse_entry < (i32)ncompletions
-		&& rect_contains_point(ac->rect, ted->mouse_pos)) {
+		&& ted_mouse_in_rect(ted, ac->rect)) {
 		// highlight moused over entry
 		Rect r = rect_xywh(x, start_y + (float)(mouse_entry - scroll) * char_height, menu_width, char_height);
 		gl_geometry_rect(r, colors[COLOR_AUTOCOMPLETE_HL]);
diff --git a/ide-document-link.c b/ide-document-link.c
index 2d43807..71307b5 100644
--- a/ide-document-link.c
+++ b/ide-document-link.c
@@ -101,7 +101,7 @@ void document_link_frame(Ted *ted) {
 	
 	arr_foreach_ptr(dl->links, DocumentLink, l) {
 		Rect r = document_link_get_rect(ted, l);
-		if (rect_contains_point(r, ted->mouse_pos)) {
+		if (ted_mouse_in_rect(ted, r)) {
 			ted->cursor = ted->cursor_hand;
 		}
 	}
diff --git a/ide-hover.c b/ide-hover.c
index ae870c3..59498f7 100644
--- a/ide-hover.c
+++ b/ide-hover.c
@@ -159,7 +159,7 @@ void hover_frame(Ted *ted, double dt) {
 	const char *text = hover->text;
 	Font *font = ted->font;
 	float char_height = text_font_char_height(font);
-	float x = ted->mouse_pos.x, y = ted->mouse_pos.y + char_height;
+	float x = ted_mouse_pos(ted).x, y = ted_mouse_pos(ted).y + char_height;
 	
 	buffer_highlight_lsp_range(buffer, hover->range, COLOR_HOVER_HL);
 	
diff --git a/lsp-parse.c b/lsp-parse.c
index 5337de5..df87a13 100644
--- a/lsp-parse.c
+++ b/lsp-parse.c
@@ -714,7 +714,7 @@ static bool parse_diagnostic(LSP *lsp, LSPRequest *request, const JSON *json, JS
 		return false;
 	diagnostic_out->message = lsp_request_add_json_string(
 		request, json,
-		json_object_get_string(json, diagnostic_in, "request")
+		json_object_get_string(json, diagnostic_in, "message")
 	);
 	JSONValue severity_val = json_object_get(json, diagnostic_in, "severity");
 	LSPDiagnosticSeverity severity = LSP_DIAGNOSTIC_SEVERITY_INFORMATION;
diff --git a/main.c b/main.c
index 12324ce..dbfb6a1 100644
--- a/main.c
+++ b/main.c
@@ -641,7 +641,7 @@ int main(int argc, char **argv) {
 				} else if (key_modifier == 0) {
 					// scroll with mouse wheel
 					Sint32 dx = event.wheel.x, dy = -event.wheel.y;
-					if (autocomplete_box_contains_point(ted, ted->mouse_pos)) {
+					if (autocomplete_box_contains_point(ted, ted_mouse_pos(ted))) {
 						autocomplete_scroll(ted, dy);
 					} else {
 						ted->scroll_total_x += dx;
@@ -886,7 +886,7 @@ int main(int argc, char **argv) {
 						ted_log(ted, "%s\n", lsp_request_string(r, m->message));
 						} break;
 					case LSP_REQUEST_PUBLISH_DIAGNOSTICS: {
-						ted_process_publish_diagnostics(ted, r);
+						ted_process_publish_diagnostics(ted, lsp, r);
 					} break;
 					default: break;
 					}
@@ -984,7 +984,7 @@ int main(int argc, char **argv) {
 				if (ted->resizing_build_output) {
 					if (ted->mouse_state & SDL_BUTTON_LMASK) {
 						// resize it
-						ted->build_output_height = clampf((y2 - ted->mouse_pos.y) / ted->window_height, 0.05f, 0.8f);
+						ted->build_output_height = clampf((y2 - ted_mouse_pos(ted).y) / ted->window_height, 0.05f, 0.8f);
 					} else {
 						// stop resizing build output
 						ted->resizing_build_output = false;
@@ -996,7 +996,7 @@ int main(int argc, char **argv) {
 						// start resizing build output
 						ted->resizing_build_output = true;
 					}
-					if (rect_contains_point(gap, ted->mouse_pos)) {
+					if (ted_mouse_in_rect(ted, gap)) {
 						ted->cursor = ted->cursor_resize_v;
 					}
 				}
diff --git a/node.c b/node.c
index ee99883..aaa730f 100644
--- a/node.c
+++ b/node.c
@@ -383,7 +383,8 @@ void node_frame(Ted *ted, Node *node, Rect r) {
 
 				if (node == ted->dragging_tab_node && i == ted->dragging_tab_idx) {
 					// make tab follow mouse
-					tab_rect.pos = vec2_add(tab_rect.pos, vec2_sub(ted->mouse_pos, ted->dragging_tab_origin));
+					tab_rect.pos = vec2_add(tab_rect.pos, 
+						vec2_sub(ted_mouse_pos(ted), ted->dragging_tab_origin));
 				}
 				
 				// tab border
@@ -447,7 +448,8 @@ void node_frame(Ted *ted, Node *node, Rect r) {
 				ted->resizing_split = NULL;
 			} else {
 				// resize the split
-				float mouse_coord = node->split_vertical ? ted->mouse_pos.y : ted->mouse_pos.x;
+				const vec2 mouse_pos = ted_mouse_pos(ted);
+				float mouse_coord = node->split_vertical ? mouse_pos.y : mouse_pos.x;
 				float rect_coord1 = (node->split_vertical ? rect_y1 : rect_x1)(r);
 				float rect_coord2 = (node->split_vertical ? rect_y2 : rect_x2)(r);
 				// make sure the split doesn't make one of the sides too small
@@ -469,7 +471,7 @@ void node_frame(Ted *ted, Node *node, Rect r) {
 			r2.size.x = r.size.x - split_pos - padding;
 			r_between = rect_xywh(r.pos.x + split_pos - padding, r.pos.y, 2 * padding, r.size.y);
 		}
-		if (rect_contains_point(r_between, ted->mouse_pos)) {
+		if (ted_mouse_in_rect(ted, r_between)) {
 			ted->cursor = resize_cursor;
 		}
 		if (ted_clicked_in_rect(ted, r_between)) 
diff --git a/ted-internal.h b/ted-internal.h
index 49ca912..e5b9874 100644
--- a/ted-internal.h
+++ b/ted-internal.h
@@ -464,6 +464,7 @@ bool buffer_handle_click(Ted *ted, TextBuffer *buffer, vec2 click, u8 times);
 void buffer_center_cursor_next_frame(TextBuffer *buffer);
 /// perform a series of checks to make sure the buffer doesn't have any invalid values
 void buffer_check_valid(TextBuffer *buffer);
+void buffer_publish_diagnostics(TextBuffer *buffer, const LSPRequest *request, LSPDiagnostic *diagnostics);
 
 // === build.c ===
 void build_frame(Ted *ted, float x1, float y1, float x2, float y2);
@@ -712,6 +713,6 @@ void ted_load_fonts(Ted *ted);
 /// Free all of ted's fonts.
 void ted_free_fonts(Ted *ted);
 /// process textDocument/publishDiagnostics request
-void ted_process_publish_diagnostics(Ted *ted, LSPRequest *request);
+void ted_process_publish_diagnostics(Ted *ted, LSP *lsp, LSPRequest *request);
 
 #endif // TED_INTERNAL_H_
diff --git a/ted.c b/ted.c
index 7ce2e87..ec04e0b 100644
--- a/ted.c
+++ b/ted.c
@@ -745,7 +745,7 @@ bool ted_get_mouse_buffer_pos(Ted *ted, TextBuffer **pbuffer, BufferPos *ppos) {
 	arr_foreach_ptr(ted->buffers, TextBufferPtr, pbuf) {
 		TextBuffer *buffer = *pbuf;
 		BufferPos pos = {0};
-		if (buffer_pixels_to_pos(buffer, ted->mouse_pos, &pos)) {
+		if (buffer_pixels_to_pos(buffer, ted_mouse_pos(ted), &pos)) {
 			if (ppos) *ppos = pos;
 			if (pbuffer) *pbuffer = buffer;
 			return true;
@@ -826,16 +826,16 @@ MessageType ted_message_type_from_lsp(LSPWindowMessageType type) {
 void ted_color_settings_for_message_type(MessageType type, ColorSetting *bg_color, ColorSetting *border_color) {
 	switch (type) {
 	case MESSAGE_ERROR:
-		*bg_color = COLOR_ERROR_BG;
-		*border_color = COLOR_ERROR_BORDER;
+		if (bg_color) *bg_color = COLOR_ERROR_BG;
+		if (border_color) *border_color = COLOR_ERROR_BORDER;
 		break;
 	case MESSAGE_WARNING:
-		*bg_color = COLOR_WARNING_BG;
-		*border_color = COLOR_WARNING_BORDER;
+		if (bg_color) *bg_color = COLOR_WARNING_BG;
+		if (border_color) *border_color = COLOR_WARNING_BORDER;
 		break;
 	case MESSAGE_INFO:
-		*bg_color = COLOR_INFO_BG;
-		*border_color = COLOR_INFO_BORDER;
+		if (bg_color) *bg_color = COLOR_INFO_BG;
+		if (border_color) *border_color = COLOR_INFO_BORDER;
 		break;
 	}
 }
@@ -876,8 +876,21 @@ bool ted_close_buffer_with_file(Ted *ted, const char *path) {
 	return true;
 }
 
-void ted_process_publish_diagnostics(Ted *ted, LSPRequest *request) {
+void ted_process_publish_diagnostics(Ted *ted, LSP *lsp, LSPRequest *request) {
 	assert(request->type == LSP_REQUEST_PUBLISH_DIAGNOSTICS);
 	LSPRequestPublishDiagnostics *pub = &request->data.publish_diagnostics;
-	printf("%u diagnostics\n",arr_len(pub->diagnostics));
+	const char *path = lsp_document_path(lsp, pub->document);
+	TextBuffer *buffer = ted_get_buffer_with_file(ted, path);
+	if (buffer) {
+		buffer_publish_diagnostics(buffer, request, pub->diagnostics);
+	}
+}
+
+
+vec2 ted_mouse_pos(Ted *ted) {
+	return ted->mouse_pos;
+}
+
+bool ted_mouse_in_rect(Ted *ted, Rect r) {
+	return rect_contains_point(r, ted->mouse_pos);
 }
diff --git a/ted.h b/ted.h
index d35fd74..8de7fc4 100644
--- a/ted.h
+++ b/ted.h
@@ -314,6 +314,11 @@ typedef struct {
 typedef struct {
 	/// position where the edit took place
 	BufferPos pos;
+	/// "end" position
+	///
+	/// for insertions, this is the position of one past the last character inserted,
+	/// for deletions, this is the position of the end of the deletion prior to applying the edit
+	BufferPos end;
 	/// number of characters (unicode codepoints, including newlines) deleted
 	///
 	/// if this is non-zero, \ref chars_inserted will be zero.
@@ -322,10 +327,6 @@ typedef struct {
 	///
 	/// if this is non-zero, \ref chars_deleted will be zero.
 	u32 chars_inserted;
-	/// number of newlines deleted
-	u32 newlines_deleted;
-	/// number of newlines inserted
-	u32 newlines_inserted;
 } EditInfo;
 
 /// this type of callback is called right after an edit is made to the buffer.
@@ -423,6 +424,10 @@ char32_t buffer_pos_move_to_matching_bracket(TextBuffer *buffer, BufferPos *pos)
 ///
 /// \returns `true` if cursor was to the right of a bracket.
 bool buffer_cursor_move_to_matching_bracket(TextBuffer *buffer);
+/// move `*pos` so that it stays in the same place after `edit` is applied.
+///
+/// if `pos` was deleted by `edit`, returns `false`.
+bool buffer_pos_move_according_to_edit(BufferPos *pos, const EditInfo *edit);
 /// ensures that `p` refers to a valid position, moving it if needed.
 void buffer_pos_validate(TextBuffer *buffer, BufferPos *p);
 /// is this a valid buffer position?
@@ -796,6 +801,12 @@ Status color_from_str(const char *str, u32 *color);
 u32 color_blend(u32 bg, u32 fg);
 /// multiply color's alpha value by `opacity`.
 u32 color_apply_opacity(u32 color, float opacity);
+/// get WCAG contrast ratio between colors
+float color_contrast_ratio(const float rgb1[3], const float rgb2[3]);
+/// get WCAG contrast ratio between colors.
+///
+/// the "alpha" components (i.e. lowest 8 bits) of `color1`, `color2` are ignored
+float color_contrast_ratio_u32(u32 color1, u32 color2);
 
 // === command.c ===
 /// parse command
@@ -1138,6 +1149,10 @@ void ted_close_buffer(Ted *ted, TextBuffer *buffer);
 bool ted_close_buffer_with_file(Ted *ted, const char *path);
 /// save all buffers
 bool ted_save_all(Ted *ted);
+/// get mouse position
+vec2 ted_mouse_pos(Ted *ted);
+/// test whether mouse is in rect
+bool ted_mouse_in_rect(Ted *ted, Rect r);
 /// reload all buffers from their files
 void ted_reload_all(Ted *ted);
 /// Change ted's font size.
diff --git a/ui.c b/ui.c
index f359241..3dd7875 100644
--- a/ui.c
+++ b/ui.c
@@ -324,7 +324,7 @@ void selector_render(Ted *ted, Selector *s) {
 		float x = r_unclipped.pos.x, y = r_unclipped.pos.y;
 		text_state.x = x; text_state.y = y;
 		
-		if (rect_contains_point(r_clipped, ted->mouse_pos) || (s->enable_cursor && s->cursor == i)) {
+		if (ted_mouse_in_rect(ted, r_clipped) || (s->enable_cursor && s->cursor == i)) {
 			// highlight it
 			gl_geometry_rect(r_clipped, settings_color(settings, COLOR_MENU_HL));
 		}
@@ -661,7 +661,7 @@ vec2 button_get_size(Ted *ted, const char *text) {
 }
 
 void button_render(Ted *ted, Rect button, const char *text, u32 color) {	
-	if (rect_contains_point(button, ted->mouse_pos)) {
+	if (ted_mouse_in_rect(ted, button)) {
 		// highlight button when hovering over it
 		u32 new_color = (color & 0xffffff00) | ((color & 0xff) / 3);
 		gl_geometry_rect(button, new_color);