//
// Globals.
//

static int step_counter = 0;
int trig_selection_loc = 0;
int param_selection_loc = 0;
int channel_selection_loc = 0;
int pattern_selection_loc = 0;
int right_col_selection_loc = 0;
int play_status = 0;
int current_pattern = 0;
int next_pattern = 0;
int current_bank = 0;
int next_bank = 0;
u32 last_trig_loc = 0;
u32 last_channel_loc = 0;
u32 last_pattern_loc = 0;
u32 last_right_col_loc = 0;
u32 last_step_counter = 0;
bool clear_screen = true;

//
// Color indexes.
//

#define COL_BG    0
#define COL_FG    1
#define COL_ACC_0 2
#define COL_ACC_1 3
#define COL_ACC_2 4
#define COL_OFF   5

#define CHAN_W 18
#define CHAN_H 8
#define CHAN_START_X 28
#define CHAN_START_Y 100
#define CHAN_OFFSET_Y 15

#define TRIG_W 15
#define TRIG_H 22
#define TRIG_START_X 55
#define TRIG_START_Y 100
#define TRIG_OFFSET_X (TRIG_W + 3)
#define TRIG_OFFSET_Y (TRIG_H + 8)

#define PIANO_W 170
#define PIANO_H 12
#define PIANO_BLACK_H 10
#define PIANO_START_X 27
#define PIANO_START_Y 80
#define PIANO_NOTE_W 2

#define NOTIF_W 170
#define NOTIF_H 10
#define NOTIF_START_X 27
#define NOTIF_START_Y 12

#define PARAMS_W 166
#define PARAMS_H 56
#define PARAMS_START_X 29
#define PARAMS_START_Y 20
#define PARAMS_BOX_W 30
#define PARAMS_BOX_H 24
#define PARAMS_BOX_OFFSET_X (PARAMS_BOX_W + 4)
#define PARAMS_BOX_OFFSET_Y (PARAMS_BOX_H + 4)

#define R_SIDEBAR_X ((TRIG_START_X) + (TRIG_OFFSET_X) * 8 + 8)

#define PAT_START_X 5
#define PAT_START_Y 16
#define PAT_W 14
#define PAT_H 10
#define PAT_OFFSET_Y 18

#define R_COL_W 30
#define BPM_START_X (R_SIDEBAR_X - 2)
#define BPM_START_Y (TRIG_START_Y + 8)
#define BPM_H 15

#define SCALE_START_X (R_SIDEBAR_X - 2)
#define SCALE_START_Y (PIANO_START_Y)
#define SCALE_H 15

#define SETTINGS_START_X (R_SIDEBAR_X - 4)
#define SETTINGS_START_Y (TRIG_START_Y + 30)
#define PLAY_START_X (R_SIDEBAR_X - 2)
#define PLAY_START_Y (TRIG_START_Y + 44)
#define STOP_START_X (R_SIDEBAR_X + 14)
#define STOP_START_Y (TRIG_START_Y + 44)
#define PLAY_STOP_W (12)
#define PLAY_STOP_H (8)

#define BANK_START_X (R_SIDEBAR_X + 5)
#define BANK_START_Y (PAT_START_Y)
#define BANK_W 12
#define BANK_H 10

#define PAT_TRIG_W 14
#define PAT_TRIG_H 14
#define PAT_TRIG_START_X 32
#define PAT_TRIG_START_Y 37
#define PAT_TRIG_OFFSET_X (PAT_TRIG_W + 7)
#define PAT_TRIG_OFFSET_Y (PAT_TRIG_H + 8)

#define SEQ_N_CHANNELS 4

enum RIGHT_COL_LOC {
    R_COL_BANK_A   = 0,
    R_COL_BANK_B   = 1,
    R_COL_BANK_C   = 2,
    R_COL_BANK_D   = 3,
    R_COL_BANK_E   = 4,
    R_COL_BANK_F   = 5,
    R_COL_SCALE    = 6,
    R_COL_BPM      = 7,
    R_COL_SETTINGS = 8,
    R_COL_PLAY     = 9,
    R_COL_STOP     = 10,
    R_COL_END,
};

// Input handling works using a FSM. The input handler is switched to whichever
// function controls each section. For example, channel selection or trigger
// selection.
typedef void (*InputHandler)(void);

InputHandler input_handler;

void handle_trigger_selection(void);
void handle_channel_selection(void);
void handle_pattern_selection(void);
void handle_param_selection_sq1(void);
void handle_param_selection_sq2(void);
void handle_param_selection_wave(void);
void handle_param_selection_noise(void);
void handle_right_col_selection(void);
void handle_param_selection_ch1(void);
void handle_param_selection_ch2(void);
void handle_param_selection_ch3(void);
void handle_param_selection_ch4(void);
void handle_pattern_chain(void);

typedef enum Scene {
    SCENE_SEQUENCER = 0,
    SCENE_SETTINGS,
} Scene;

static Scene scene = SCENE_SEQUENCER;
static Scene next_scene = SCENE_SEQUENCER;

typedef struct Notification {
    // We can only fit 31 characters on the notification bar at the moment.
    // Leaving an extra character for \0.
    char msg[32];
    s16 time;
} Notification;

static Notification notif = {0};

#define NOTIF_TIME (80 + 32)

#define MAX_CHAIN 16
typedef struct Chain {
    u8 chain[MAX_CHAIN];
    u8 active[MAX_CHAIN];
    u8 len;
    u8 current;
    u8 playing;
    u8 enabled;
} Chain;

typedef enum ChainButtons {
    CHAIN_BTN_ENABLE = 16,
    CHAIN_BTN_CLEAR = 17,
    CHAIN_BTN_RANDOM = 18,
} ChainButtons;

static Chain chain = {0};

typedef enum Prob {
    PROB_FOUR_FOUR,
    PROB_THREE_FOUR,
    PROB_TWO_FOUR,
    PROB_ONE_FOUR,
    PROB_THREE_THREE,
    PROB_TWO_THREE,
    PROB_ONE_THREE,
    PROB_TWO_TWO,
    PROB_ONE_TWO,
    PROB_NOT_FIRST,
    PROB_FIRST,
    PROB_100,
    PROB_80,
    PROB_60,
    PROB_40,
    PROB_20,
    PROB_NUM,
} Prob;

bool redraw_pattern_buttons = true;
bool redraw_play_pause = true;
bool redraw_trigs = true;
bool redraw_channels = true;
bool redraw_bank_buttons = true;
bool redraw_params = true;
bool redraw_bpm = true;
bool redraw_scale = true;
bool update_bpm = false;
u8 bar_counter = 0;

typedef enum WaveEnv {
    WAV_ENV_START,
    WAV_ENV_ATTACK,
    WAV_ENV_DECAY,
    WAV_ENV_END,
    WAV_ENV_OFF,
} WaveEnv;

enum WAVES {
    WAVE_SIN,
    WAVE_SAW,
    WAVE_SQUARE,
    WAVE_MAX,
};

#define WAVE_SIZE 4
#define WAVE_VARS 4

typedef u32 Wave[WAVE_SIZE];

static WaveEnv wave_env = WAV_ENV_OFF;
static const Wave *wave_target;
static u32 wave_freq;
static int wave_env_ticks = 0;
static int wave_env_attack = 8;
static int wave_env_decay = 8;
static int wave_env_prog = 0;
static Wave current_wave[8] = {0};