#define SPRITE_NOTE_NAMES_W 16
#define SPRITE_NOTE_NAMES_H 8

u32 sprite_note_names[] = {
    0x77417111, 0x77000000, 0x00000000, 0x00000000,
    0x13157555, 0x33000000, 0x07040701, 0x07000000,
    0x73457515, 0x73000000, 0x00000000, 0x00000000,
    0x17117351, 0x37000000, 0x07040701, 0x07000000,
    0x77417311, 0x77000000, 0x00000000, 0x00000000,
    0x77417311, 0x71000000, 0x00000000, 0x00000000,
    0x17117155, 0x37000000, 0x07040701, 0x07000000,
    0x77417115, 0x77000000, 0x00000000, 0x00000000,
    0x17157557, 0x35000000, 0x07040701, 0x07000000,
    0x77457517, 0x75000000, 0x00000000, 0x00000000,
    0x17157355, 0x37000000, 0x07040701, 0x07000000,
    0x77457315, 0x77000000, 0x00000000, 0x00000000,
    0x77416141, 0x77000000, 0x00000000, 0x00000000,
    0x13157555, 0x33000000, 0x07040604, 0x07000000,
    0x73456545, 0x73000000, 0x00000000, 0x00000000,
    0x17117351, 0x37000000, 0x07040604, 0x07000000,
    0x77416341, 0x77000000, 0x00000000, 0x00000000,
    0x77416341, 0x71000000, 0x00000000, 0x00000000,
    0x17117155, 0x37000000, 0x07040604, 0x07000000,
    0x77416145, 0x77000000, 0x00000000, 0x00000000,
    0x17157557, 0x35000000, 0x07040604, 0x07000000,
    0x77456547, 0x75000000, 0x00000000, 0x00000000,
    0x17157355, 0x37000000, 0x07040604, 0x07000000,
    0x77456345, 0x77000000, 0x00000000, 0x00000000,
    0x47615171, 0x47000000, 0x00000000, 0x00000000,
    0x13157555, 0x33000000, 0x04060507, 0x04000000,
    0x43655575, 0x43000000, 0x00000000, 0x00000000,
    0x17117351, 0x37000000, 0x04060507, 0x04000000,
    0x47615371, 0x47000000, 0x00000000, 0x00000000,
    0x47615371, 0x41000000, 0x00000000, 0x00000000,
    0x17117155, 0x37000000, 0x04060507, 0x04000000,
    0x47615175, 0x47000000, 0x00000000, 0x00000000,
    0x17157557, 0x35000000, 0x04060507, 0x04000000,
    0x47655577, 0x45000000, 0x00000000, 0x00000000,
    0x17157355, 0x37000000, 0x04060507, 0x04000000,
    0x47655375, 0x47000000, 0x00000000, 0x00000000,
    0x77117141, 0x77000000, 0x00000000, 0x00000000,
    0x13157555, 0x33000000, 0x07010704, 0x07000000,
    0x73157545, 0x73000000, 0x00000000, 0x00000000,
    0x17117351, 0x37000000, 0x07010704, 0x07000000,
    0x77117341, 0x77000000, 0x00000000, 0x00000000,
    0x77117341, 0x71000000, 0x00000000, 0x00000000,
    0x17117155, 0x37000000, 0x07010704, 0x07000000,
    0x77117145, 0x77000000, 0x00000000, 0x00000000,
    0x17157557, 0x35000000, 0x07010704, 0x07000000,
    0x77157547, 0x75000000, 0x00000000, 0x00000000,
    0x17157355, 0x37000000, 0x07010704, 0x07000000,
    0x77157345, 0x77000000, 0x00000000, 0x00000000,
    0x77117151, 0x77000000, 0x00000000, 0x00000000,
    0x13157555, 0x33000000, 0x07010705, 0x07000000,
    0x73157555, 0x73000000, 0x00000000, 0x00000000,
    0x17117351, 0x37000000, 0x07010705, 0x07000000,
    0x77117351, 0x77000000, 0x00000000, 0x00000000,
    0x77117351, 0x71000000, 0x00000000, 0x00000000,
    0x17117155, 0x37000000, 0x07010705, 0x07000000,
    0x77117155, 0x77000000, 0x00000000, 0x00000000,
    0x17157557, 0x35000000, 0x07010705, 0x07000000,
    0x77157557, 0x75000000, 0x00000000, 0x00000000,
    0x17157355, 0x37000000, 0x07010705, 0x07000000,
    0x77157355, 0x77000000, 0x00000000, 0x00000000,
    0x77412111, 0x17000000, 0x00000000, 0x00000000,
    0x13157555, 0x33000000, 0x07040201, 0x01000000,
    0x73452515, 0x13000000, 0x00000000, 0x00000000,
    0x17117351, 0x37000000, 0x07040201, 0x01000000,
    0x77412311, 0x17000000, 0x00000000, 0x00000000,
    0x77412311, 0x11000000, 0x00000000, 0x00000000,
    0x17117155, 0x37000000, 0x07040201, 0x01000000,
    0x77412115, 0x17000000, 0x00000000, 0x00000000,
    0x17157557, 0x35000000, 0x07040201, 0x01000000,
    0x77452517, 0x15000000, 0x00000000, 0x00000000,
    0x17157355, 0x37000000, 0x07040201, 0x01000000,
    0x77452315, 0x17000000, 0x00000000, 0x00000000,
    0x77517151, 0x77000000, 0x00000000, 0x00000000,
};

typedef struct SeqTrigger {
    bool trigger;
    Note note;
    // TODO: ...
} SeqTrigger;

static SeqTrigger sequence_synth[] = {
    {true, NOTE_D_4},
    {true, NOTE_F_4},
    {true, NOTE_A_4},
    {true, NOTE_C_5},

    {true, NOTE_D_4},
    {false, NOTE_D_4},
    {false, NOTE_D_4},
    {false, NOTE_D_4},

    {true, NOTE_D_4},
    {true, NOTE_F_4},
    {true, NOTE_A_4},
    {true, NOTE_C_5},

    {true, NOTE_D_4},
    {false, NOTE_D_4},
    {true, NOTE_A_4},
    {false, NOTE_A_5},
};

static int step_counter = 0;
static Note active_note;

void
irq_timer_0(void) {
    active_note = sequence_synth[step_counter].note;
    if (sequence_synth[step_counter].trigger) {
        SOUND_SQUARE1_CTRL = SOUND_SQUARE_ENV_VOL(13) | SOUND_SQUARE_ENV_TIME(4) | SOUND_SQUARE_DUTY(2);
        SOUND_SQUARE1_FREQ = SOUND_SQUARE_RESET | sound_rates[active_note];
    }
    step_counter = (step_counter + 1) % 16;
}

void
set_time(int bpm) {
    // The number of ticks of a 1024 cycle clock in a step based on the BPM can
    // be calculated as:
    //     X bpm -> 60000 / 4 / bpm = Y ms = Ye-3 s
    //     Y ms  -> Ye-3 / 59.99e-9 /1024 = Z ticks
    // We have to operate on integer values, so the numbers have been
    // precalculated to `n_ticks = 244181 / bmp`
    int n_ticks = -244181 / bpm;

    irs_set(IRQ_TIMER_0, irq_timer_0);
    TIMER_DATA_0 = n_ticks;
    TIMER_CTRL_0 = TIMER_CTRL_IRQ | TIMER_CTRL_ENABLE | TIMER_CTRL_FREQ_3;
}

static size_t note_sprites_id = 0;

//
// Sequencer sprite memory.
//
// Currently we load all sequencer sprite memory in the VRAM:
//
// - Note names: 0-73x2 tiles
// - ...
//
// The order of OBJs correspond to:
//
// - 000-015 step note names.
// - 015-029 step trigger steps.
// - 030-045 step duration indicators.
// - 046-046 current step marker.
// - 047-047 trigger selection indicator.
//

size_t obj_counter = 0;

typedef struct SeqSprite {
    u8 id;
    int x;
    int y;
    u16 obj_attr_0;
    u16 obj_attr_1;
    u16 obj_attr_2;
} SeqSprite;

#define SEQ_POS_X 20
#define SEQ_POS_Y 20

// SeqSprite seq_sprites[] = {
//     // 000-015: Step note names.
//     {
//         .x = SEQ_POS_X,
//         .y = SEQ_POS_Y,
//         .obj_attr_0 = OBJ_SHAPE_WIDE,
//         .obj_attr_1 = OBJ_SHAPE_SMALL,
//         .obj_attr_2 = 0,
//     },
// };

SeqSprite seq_sprites[16] = {0};

void
init_sequencer_sprites() {
    // Load note sprites.
    note_sprites_id = load_packed_sprite_data(&sprite_note_names, 2, 73);

    for (size_t i = 0; i < 16; ++i) {
        int x = SEQ_POS_X + i * 16;
        int y = SEQ_POS_Y;
        if (i >= 8) {
            y += 32;
            x -= 8 * 16;
        }
        seq_sprites[i].x = x;
        seq_sprites[i].y = y;

        seq_sprites[i].id = obj_counter++;
        seq_sprites[i].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_Y_COORD(y);
        // TODO: They should start hidden until the update function changes that.
        // seq_sprites[i].obj_attr_0 = OBJ_SHAPE_WIDE | OBJ_HIDDEN;
        seq_sprites[i].obj_attr_1 = OBJ_SIZE_SMALL | OBJ_X_COORD(x);
    }
}

void
render_sequencer_sprites() {
    size_t len = sizeof(seq_sprites) / sizeof(SeqSprite);
    for (size_t i = 0; i < len; ++i) {
        size_t id = seq_sprites[i].id;
        // TODO: This needs to be done in an update function, not here.
        size_t base_tile = sequence_synth[i].note;
        seq_sprites[i].obj_attr_2 = base_tile;

        OBJ_ATTR_0(id) = seq_sprites[i].obj_attr_0;
        OBJ_ATTR_1(id) = seq_sprites[i].obj_attr_1;
        OBJ_ATTR_2(id) = seq_sprites[i].obj_attr_2;
    }
}