Refactor Leader key feature (#19632)

Co-authored-by: Drashna Jaelre <drashna@live.com>

quantum/leader.c

@@ -0,0 +1,101 @@
+// Copyright 2023 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "leader.h"
+#include "timer.h"
+#include "util.h"
+
+#include <string.h>
+
+#ifndef LEADER_TIMEOUT
+#    define LEADER_TIMEOUT 300
+#endif
+
+// Leader key stuff
+bool     leading              = false;
+uint16_t leader_time          = 0;
+uint16_t leader_sequence[5]   = {0, 0, 0, 0, 0};
+uint8_t  leader_sequence_size = 0;
+
+__attribute__((weak)) void leader_start_user(void) {}
+
+__attribute__((weak)) void leader_end_user(void) {}
+
+void leader_start(void) {
+    if (leading) {
+        return;
+    }
+    leader_start_user();
+    leading              = true;
+    leader_time          = timer_read();
+    leader_sequence_size = 0;
+    memset(leader_sequence, 0, sizeof(leader_sequence));
+}
+
+void leader_end(void) {
+    leading = false;
+    leader_end_user();
+}
+
+void leader_task(void) {
+    if (leader_sequence_active() && leader_sequence_timed_out()) {
+        leader_end();
+    }
+}
+
+bool leader_sequence_active(void) {
+    return leading;
+}
+
+bool leader_sequence_add(uint16_t keycode) {
+    if (leader_sequence_size >= ARRAY_SIZE(leader_sequence)) {
+        return false;
+    }
+
+#if defined(LEADER_NO_TIMEOUT)
+    if (leader_sequence_size == 0) {
+        leader_reset_timer();
+    }
+#endif
+
+    leader_sequence[leader_sequence_size] = keycode;
+    leader_sequence_size++;
+
+    return true;
+}
+
+bool leader_sequence_timed_out(void) {
+#if defined(LEADER_NO_TIMEOUT)
+    return leader_sequence_size > 0 && timer_elapsed(leader_time) > LEADER_TIMEOUT;
+#else
+    return timer_elapsed(leader_time) > LEADER_TIMEOUT;
+#endif
+}
+
+void leader_reset_timer(void) {
+    leader_time = timer_read();
+}
+
+bool leader_sequence_is(uint16_t kc1, uint16_t kc2, uint16_t kc3, uint16_t kc4, uint16_t kc5) {
+    return leader_sequence[0] == kc1 && leader_sequence[1] == kc2 && leader_sequence[2] == kc3 && leader_sequence[3] == kc4 && leader_sequence[4] == kc5;
+}
+
+bool leader_sequence_one_key(uint16_t kc) {
+    return leader_sequence_is(kc, 0, 0, 0, 0);
+}
+
+bool leader_sequence_two_keys(uint16_t kc1, uint16_t kc2) {
+    return leader_sequence_is(kc1, kc2, 0, 0, 0);
+}
+
+bool leader_sequence_three_keys(uint16_t kc1, uint16_t kc2, uint16_t kc3) {
+    return leader_sequence_is(kc1, kc2, kc3, 0, 0);
+}
+
+bool leader_sequence_four_keys(uint16_t kc1, uint16_t kc2, uint16_t kc3, uint16_t kc4) {
+    return leader_sequence_is(kc1, kc2, kc3, kc4, 0);
+}
+
+bool leader_sequence_five_keys(uint16_t kc1, uint16_t kc2, uint16_t kc3, uint16_t kc4, uint16_t kc5) {
+    return leader_sequence_is(kc1, kc2, kc3, kc4, kc5);
+}