Refactor Leader key feature (#19632)

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

1 files changed, 119 insertions, 0 deletions

diff --git a/quantum/leader.h b/quantum/leader.h
new file mode 100644
index 0000000000..1999006c56
--- /dev/null
+++ b/quantum/leader.h
@@ -0,0 +1,119 @@
+// Copyright 2023 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <stdbool.h>
+#include <stdint.h>
+
+/**
+ * \defgroup leader
+ *
+ * Leader Key
+ * \{
+ */
+
+/**
+ * \brief User callback, invoked when the leader sequence begins.
+ */
+void leader_start_user(void);
+
+/**
+ * \brief User callback, invoked when the leader sequence ends.
+ */
+void leader_end_user(void);
+
+/**
+ * Begin the leader sequence, resetting the buffer and timer.
+ */
+void leader_start(void);
+
+/**
+ * End the leader sequence.
+ */
+void leader_end(void);
+
+void leader_task(void);
+
+/**
+ * Whether the leader sequence is active.
+ */
+bool leader_sequence_active(void);
+
+/**
+ * Add the given keycode to the sequence buffer.
+ *
+ * If `LEADER_NO_TIMEOUT` is defined, the timer is reset if the buffer is empty.
+ *
+ * \param keycode The keycode to add.
+ *
+ * \return `true` if the keycode was added, `false` if the buffer is full.
+ */
+bool leader_sequence_add(uint16_t keycode);
+
+/**
+ * Whether the leader sequence has reached the timeout.
+ *
+ * If `LEADER_NO_TIMEOUT` is defined, the buffer must also contain at least one key.
+ */
+bool leader_sequence_timed_out(void);
+
+/**
+ * Reset the leader sequence timer.
+ */
+void leader_reset_timer(void);
+
+/**
+ * Check the sequence buffer for the given keycode.
+ *
+ * \param kc The keycode to check.
+ *
+ * \return `true` if the sequence buffer matches.
+ */
+bool leader_sequence_one_key(uint16_t kc);
+
+/**
+ * Check the sequence buffer for the given keycodes.
+ *
+ * \param kc1 The first keycode to check.
+ * \param kc2 The second keycode to check.
+ *
+ * \return `true` if the sequence buffer matches.
+ */
+bool leader_sequence_two_keys(uint16_t kc1, uint16_t kc2);
+
+/**
+ * Check the sequence buffer for the given keycodes.
+ *
+ * \param kc1 The first keycode to check.
+ * \param kc2 The second keycode to check.
+ * \param kc3 The third keycode to check.
+ *
+ * \return `true` if the sequence buffer matches.
+ */
+bool leader_sequence_three_keys(uint16_t kc1, uint16_t kc2, uint16_t kc3);
+
+/**
+ * Check the sequence buffer for the given keycodes.
+ *
+ * \param kc1 The first keycode to check.
+ * \param kc2 The second keycode to check.
+ * \param kc3 The third keycode to check.
+ * \param kc4 The fourth keycode to check.
+ *
+ * \return `true` if the sequence buffer matches.
+ */
+bool leader_sequence_four_keys(uint16_t kc1, uint16_t kc2, uint16_t kc3, uint16_t kc4);
+
+/**
+ * Check the sequence buffer for the given keycodes.
+ *
+ * \param kc1 The first keycode to check.
+ * \param kc2 The second keycode to check.
+ * \param kc3 The third keycode to check.
+ * \param kc4 The fourth keycode to check.
+ * \param kc5 The fifth keycode to check.
+ *
+ * \return `true` if the sequence buffer matches.
+ */
+bool leader_sequence_five_keys(uint16_t kc1, uint16_t kc2, uint16_t kc3, uint16_t kc4, uint16_t kc5);
+
+/** \} */