Implement search iteration

The interactive search now has its own keymap, overriding "input".

Closes #5

sdn.cpp

@@ -459,8 +459,13 @@ static map<wint_t, action> g_input_actions {
 	{CTRL ('A'), ACTION_INPUT_BEGINNING}, {KEY (HOME), ACTION_INPUT_BEGINNING},
 	{CTRL ('E'), ACTION_INPUT_END}, {KEY (END), ACTION_INPUT_END},
 };
+static map<wint_t, action> g_search_actions {
+	{CTRL ('P'), ACTION_UP}, {KEY (UP), ACTION_UP},
+	{CTRL ('N'), ACTION_DOWN}, {KEY (DOWN), ACTION_DOWN},
+};
 static const map<string, map<wint_t, action>*> g_binding_contexts {
 	{"normal", &g_normal_actions}, {"input", &g_input_actions},
+	{"search", &g_search_actions},
 };
 
 #define LS(XX) XX(NORMAL, "no") XX(FILE, "fi") XX(RESET, "rs") \
@@ -527,16 +532,18 @@ static struct {
 	bool out_of_date;                   ///< Entries may be out of date
 
 	const wchar_t *editor;              ///< Prompt string for editing
+	wstring editor_info;                ///< Right-side prompt while editing
 	wstring editor_line;                ///< Current user input
 	int editor_cursor = 0;              ///< Cursor position
 	bool editor_inserting;              ///< Inserting a literal character
 	void (*editor_on_change) ();        ///< Callback on editor change
 	void (*editor_on_confirm) ();       ///< Callback on editor confirmation
+	map<action, void (*) ()> editor_on; ///< Handlers for custom actions
 
-	enum { AT_CURSOR, AT_BAR, AT_CWD, AT_INPUT, AT_CMDLINE, AT_COUNT };
-	chtype attrs[AT_COUNT] = {A_REVERSE, 0, A_BOLD, 0, 0};
+	enum { AT_CURSOR, AT_BAR, AT_CWD, AT_INPUT, AT_INFO, AT_CMDLINE, AT_COUNT };
+	chtype attrs[AT_COUNT] = {A_REVERSE, 0, A_BOLD, 0, A_ITALIC, 0};
 	const char *attr_names[AT_COUNT] =
-		{"cursor", "bar", "cwd", "input", "cmdline"};
+		{"cursor", "bar", "cwd", "input", "info", "cmdline"};
 
 	map<int, chtype> ls_colors;         ///< LS_COLORS decoded
 	map<string, chtype> ls_exts;        ///< LS_COLORS file extensions
@@ -750,9 +757,16 @@ fun update () {
 	curs_set (0);
 	if (g.editor) {
 		move (LINES - 1, 0);
-		auto prompt = apply_attrs (wstring (g.editor) + L": ", 0);
-		auto line = apply_attrs (g.editor_line, 0);
-		print (prompt + line, COLS - 1);
+		auto prompt = apply_attrs (wstring (g.editor) + L": ", 0),
+			line = apply_attrs (g.editor_line, 0),
+			info = apply_attrs (g.editor_info, g.attrs[g.AT_INFO]);
+
+		auto info_width = compute_width (info);
+		if (print (prompt + line, COLS - 1) < COLS - info_width) {
+			move (LINES - 1, COLS - info_width);
+			print (info, info_width);
+		}
+
 		auto start = sanitize (prompt + line.substr (0, g.editor_cursor));
 		move (LINES - 1, compute_width (start));
 		curs_set (1);
@@ -989,17 +1003,32 @@ fun show_help () {
 	fclose (contents);
 }
 
-fun search (const wstring &needle) {
-	int best = g.cursor, best_n = 0;
-	for (int i = 0; i < int (g.entries.size ()); i++) {
-		auto o = (i + g.cursor) % g.entries.size ();
+/// Stays on the current match when there are no better ones, unless it's pushed
+fun search (const wstring &needle, int push) -> int {
+	int best = g.cursor, best_n = 0, matches = 0, step = push != 0 ? push : 1;
+	for (int i = 0, count = g.entries.size (); i < count; i++) {
+		auto o = (g.cursor + (count + i * step) + (count + push)) % count;
 		int n = prefix_length (to_wide (g.entries[o].filename), needle);
+		matches += n == needle.size ();
 		if (n > best_n) {
 			best = o;
 			best_n = n;
 		}
 	}
 	g.cursor = best;
+	return matches;
+}
+
+fun search_interactive (int push) {
+	int matches = search (g.editor_line, push);
+	if (g.editor_line.empty ())
+		g.editor_info.clear ();
+	else if (matches == 0)
+		g.editor_info = L"(no match)";
+	else if (matches == 1)
+		g.editor_info = L"(1 match)";
+	else
+		g.editor_info = L"(" + to_wstring (matches) + L" matches)";
 }
 
 fun fix_cursor_and_offset () {
@@ -1058,7 +1087,7 @@ fun pop_levels (const string& old_cwd) {
 
 	fix_cursor_and_offset ();
 	if (!anchor.empty () && at_cursor ().filename != anchor)
-		search (to_wide (anchor));
+		search (to_wide (anchor), 0);
 }
 
 fun explode_path (const string &path, vector<string> &out) {
@@ -1189,25 +1218,37 @@ fun move_towards_spacing (int diff) -> bool {
 }
 
 fun handle_editor (wint_t c) {
-	auto i = g_input_actions.find (g.editor_inserting ? WEOF : c);
+	auto action = ACTION_NONE;
 	if (g.editor_inserting) {
 		(void) halfdelay (1);
 		g.editor_inserting = false;
+	} else {
+		auto i = g_input_actions.find (c);
+		if (i != g_input_actions.end ())
+			action = i->second;
+
+		auto m = g_binding_contexts.find (to_mb (g.editor));
+		if (m != g_binding_contexts.end ()
+		 && (i = m->second->find (c)) != m->second->end ())
+			action = i->second;
 	}
 
-	switch (i == g_input_actions.end () ? ACTION_NONE : i->second) {
+	auto original = g.editor_line;
+	switch (action) {
 	case ACTION_INPUT_CONFIRM:
 		if (g.editor_on_confirm)
 			g.editor_on_confirm ();
 		// Fall-through
 	case ACTION_INPUT_ABORT:
 		g.editor = 0;
+		g.editor_info.clear ();
 		g.editor_line.clear ();
 		g.editor_cursor = 0;
 		g.editor_inserting = false;
 		g.editor_on_change = nullptr;
 		g.editor_on_confirm = nullptr;
-		break;
+		g.editor_on.clear ();
+		return;
 	case ACTION_INPUT_BEGINNING:
 		g.editor_cursor = 0;
 		break;
@@ -1251,15 +1292,17 @@ fun handle_editor (wint_t c) {
 		g.editor_inserting = true;
 		break;
 	default:
-		if (c & (ALT | SYM)) {
+		if (auto handler = g.editor_on[action]) {
+			handler ();
+		} else if (c & (ALT | SYM)) {
 			beep ();
 		} else {
 			g.editor_line.insert (g.editor_cursor, 1, c);
 			g.editor_cursor++;
-			if (g.editor_on_change)
-				g.editor_on_change ();
 		}
 	}
+	if (g.editor_on_change && g.editor_line != original)
+		g.editor_on_change ();
 }
 
 fun handle (wint_t c) -> bool {
@@ -1371,12 +1414,10 @@ fun handle (wint_t c) -> bool {
 
 	case ACTION_SEARCH:
 		g.editor = L"search";
-		g.editor_on_change = [] {
-			search (g.editor_line);
-		};
-		g.editor_on_confirm = [] {
-			choose (at_cursor ());
-		};
+		g.editor_on_change       = [] { search_interactive (0); };
+		g.editor_on[ACTION_UP]   = [] { search_interactive (-1); };
+		g.editor_on[ACTION_DOWN] = [] { search_interactive (+1); };
+		g.editor_on_confirm      = [] { choose (at_cursor ()); };
 		break;
 	case ACTION_RENAME_PREFILL:
 		g.editor_line = to_wide (current.filename);