From 7f57051c51c16c88e5dcaa7bd51ccaec31469c4a Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Thu, 13 Jul 2023 12:00:11 +0200
Subject: Add working pattern chaining prototype

---
 src/sequencer.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 72 insertions(+), 4 deletions(-)

(limited to 'src/sequencer.c')

diff --git a/src/sequencer.c b/src/sequencer.c
index 44ff90e..8d79c65 100644
--- a/src/sequencer.c
+++ b/src/sequencer.c
@@ -47,6 +47,30 @@ gate_on(void) {
     TIMER_CTRL_3 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
 }
 
+u8
+find_next_pattern(void) {
+    u8 idx = (chain.current + 1) % 16;
+    for (size_t i = 0; i < MAX_CHAIN; i++) {
+        if (chain.active[idx] == 1) {
+            break;
+        }
+        idx = (idx + 1) % 16;
+    }
+    return idx;
+}
+
+u8
+find_prev_pattern(void) {
+    u8 idx = chain.current == 0 ? 15 : (chain.current - 1);
+    for (size_t i = 0; i < MAX_CHAIN; i++) {
+        if (chain.active[idx] == 1) {
+            break;
+        }
+        idx = chain.current == 0 ? 15 : (chain.current - 1);
+    }
+    return idx;
+}
+
 void
 play_step(void) {
     Pattern *pat = &patterns[current_pattern];
@@ -54,6 +78,18 @@ play_step(void) {
         current_pattern = next_pattern;
         redraw_pattern_buttons = true;
         update_bpm = true;
+    } else if (chain.len != 0 && step_counter == 15) {
+        redraw_pattern_buttons = true;
+        update_bpm = true;
+        if (!chain.playing) {
+            next_pattern = chain.chain[chain.current];
+            current_pattern = next_pattern;
+        } else {
+            chain.current = find_next_pattern();
+            next_pattern = chain.chain[chain.current];
+            current_pattern = next_pattern;
+        }
+        chain.playing = true;
     }
     if (pat->ch1.active) {
         TriggerNote *trig = &pat->ch1.notes[step_counter];
@@ -316,6 +352,9 @@ stop_sound(void) {
 void
 stop_playing(void) {
     step_counter = 0;
+    chain.current = 15;
+    chain.current = find_next_pattern();
+    chain.playing = false;
     stop_sound();
 }
 
@@ -323,6 +362,15 @@ void
 toggle_playing(void) {
     play_status ^= 1;
     step_counter = 0;
+    chain.current = 15;
+    chain.current = find_next_pattern();
+    chain.playing = false;
+    if (current_pattern == next_pattern && chain.len > 0) {
+        chain.playing = true;
+        next_pattern = chain.chain[chain.current];
+        current_pattern = next_pattern;
+    }
+    redraw_pattern_buttons = true;
     SOUND_SQUARE1_CTRL = 0;
     SOUND_SQUARE2_CTRL = 0;
     SOUND_WAVE_CTRL = 0;
@@ -351,6 +399,12 @@ pause_playing(void) {
     SOUND_SQUARE2_CTRL = 0;
     SOUND_WAVE_CTRL = 0;
     SOUND_NOISE_CTRL = 0;
+    chain.playing = false;
+    if (current_pattern == next_pattern && chain.len > 0) {
+        chain.playing = true;
+        next_pattern = chain.chain[chain.current];
+        current_pattern = next_pattern;
+    }
     redraw_play_pause = true;
     if (settings.sync == SYNC_IN_LINK) {
         return;
@@ -530,23 +584,37 @@ handle_pattern_selection(void) {
             }
         }
         if (slot > -1) {
+            if (chain.len == 0) {
+                chain.current = slot;
+            }
             chain.chain[slot] = pattern_selection_loc;
             chain.active[slot] = 1;
-            chain.len++; // TODO: remove
+            chain.len++;
         }
     }
     if (key_tap(KEY_L)) {
         // Find last active slot.
         s16 slot = -1;
+        bool update_current = false;
         for (size_t i = 0; i < 16; i++) {
-            if (chain.active[15 - i] == 1) {
-                slot = 15 - i;
+            size_t idx = 15 - i;
+            if (chain.active[idx] == 1) {
+                // If the pattern is currently playing it can't be removed.
+                if (play_status && idx == chain.current) {
+                    continue;
+                } else if (idx == chain.current) {
+                    update_current = true;
+                }
+                slot = idx;
                 break;
             }
         }
         if (slot > -1) {
             chain.active[slot] = 0;
-            chain.len--; // TODO: remove
+            chain.len--;
+            if (update_current) {
+                chain.current = find_prev_pattern();
+            }
         }
     }
 }
-- 
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