/*
 * PANAGOTCHI  --  a Tamagotchi-style virtual pet for the CH32V003F4P6 badge.
 *
 * Hardware (see pinout.md):
 *   PA1            indicator LED (active-high)
 *   PC0            OK button     (active-low, internal pull-up)
 *   PD5            Right button  (active-low, internal pull-up)
 *   PD6            Left button   (active-low, internal pull-up)
 *   PC1/PC2        SSD1306 128x64 OLED over I2C1 (driven by ssd1306_i2c.h)
 *   PD2            passive piezo buzzer (square-wave bit-bang tone)
 *
 * Controls: Left / Right move the menu cursor, OK activates the selected
 * action. On the stats / dead screens any button returns / restarts.
 */

#include "ch32fun.h"
#include <stdio.h>

#define SSD1306_128X64          // 128x64 panel (see pinout.md / OLED size)
#include "ssd1306_i2c.h"
#include "ssd1306.h"
#include "sprites.h"

// ----------------------------------------------------------------- pins
#define LED_PIN    PA1
#define BTN_OK     PC0
#define BTN_RIGHT  PD5
#define BTN_LEFT   PD6
#define BUZZER     PD2

// ----------------------------------------------------------------- tuning
#define FRAME_MS        60      // main loop period
#define TICK_FRAMES     250     // stat update every ~15 s (250 * 60 ms)
#define ANIM_FRAMES     12      // how long an action reaction is shown

// With the values below an untended pet survives roughly half an hour:
// a need empties in ~20 min, after which health bleeds down over ~10 more.

// ----------------------------------------------------------------- state
enum { SCR_MAIN, SCR_STATS, SCR_DEAD, SCR_SETTINGS };

// notification thresholds: gentle chirp at <50%, urgent at <20%
enum { N_FOOD, N_FUN, N_ENGY, N_WASH, N_COUNT };

typedef struct {
	int8_t   satiety;     // 0..100  (fullness)
	int8_t   happy;       // 0..100
	int8_t   energy;      // 0..100
	int8_t   hygiene;     // 0..100
	int8_t   health;      // 0..100
	uint16_t age_min;     // age in game-minutes (one per tick)
	uint8_t  poop;        // 0..3 piles on the floor
	uint8_t  sleeping;    // 1 while napping
	uint8_t  alive;
} Pet;

static Pet      pet;
static uint8_t  screen;
static uint8_t  cursor;          // selected menu icon 0..ICON_COUNT-1
static uint8_t  anim_exp;        // expression forced during a reaction
static uint8_t  anim_timer;      // frames remaining for the reaction
static uint32_t frame;           // free-running frame counter
static uint16_t tick_acc;        // frames since last stat tick
static uint8_t  warn_flag[N_COUNT]; // already chirped a <50% warning
static uint8_t  crit_flag[N_COUNT]; // already chirped a <20% warning

// settings
static uint8_t  sound_on    = 1;
static uint8_t  timeout_idx = 1; // index into screen_timeout_opts (default 30 s)
static uint8_t  set_sel     = 0; // highlighted row on the settings screen

// screen-off-on-inactivity options, in frames (0 = never sleep the display)
static const uint16_t screen_timeout_opts[] = { 250, 500, 1000, 0 };
static const char *const screen_timeout_names[] = { "15s", "30s", "60s", "Off" };
#define TIMEOUT_OPT_COUNT 4
#define SETTINGS_ROWS     3      // screen-off, sound, back

// display power state
static uint8_t  disp_on     = 1;
static uint32_t idle_frames = 0; // frames since the last button activity

// menu icon order must match sprites.h menu_icons[] / menu_labels[]
enum { ACT_FEED, ACT_PLAY, ACT_SLEEP, ACT_CLEAN, ACT_HEAL, ACT_STATS, ACT_SETTINGS };

// ----------------------------------------------------------------- helpers
static int8_t clamp100(int v) { return v < 0 ? 0 : (v > 100 ? 100 : v); }

// short square-wave beep on the passive piezo (blocking, ms-scale only)
static void beep(uint16_t freq, uint16_t ms)
{
	if (!sound_on) return;
	if (freq == 0) { Delay_Ms(ms); return; }
	uint32_t half   = 500000u / freq;            // half-period in us
	uint32_t cycles = ((uint32_t)ms * 1000u) / (half * 2u);
	for (uint32_t i = 0; i < cycles; i++) {
		funDigitalWrite(BUZZER, FUN_HIGH);
		Delay_Us(half);
		funDigitalWrite(BUZZER, FUN_LOW);
		Delay_Us(half);
	}
}

static void led_blink(void)
{
	funDigitalWrite(LED_PIN, FUN_HIGH);
	Delay_Ms(30);
	funDigitalWrite(LED_PIN, FUN_LOW);
}

static void pet_reset(void)
{
	pet.satiety  = 80;
	pet.happy    = 80;
	pet.energy   = 90;
	pet.hygiene  = 100;
	pet.health   = 100;
	pet.age_min  = 0;
	pet.poop     = 0;
	pet.sleeping = 0;
	pet.alive    = 1;
	screen = SCR_MAIN;
	cursor = 0;
	for (int i = 0; i < N_COUNT; i++) { warn_flag[i] = 0; crit_flag[i] = 0; }
}

// Chirp once when a need first drops below 50% (gentle) or 20% (urgent),
// re-arming only after it recovers. Audible even while the screen is off,
// so it works as a "tend to me" reminder.
static void notify(uint8_t idx, int8_t val)
{
	if (val < 20) {
		if (!crit_flag[idx]) {           // urgent: descending triple
			beep(1568, 60); beep(1175, 60); beep(880, 90);
			crit_flag[idx] = 1; warn_flag[idx] = 1;
		}
	} else if (val < 50) {
		if (!warn_flag[idx]) {           // gentle: single chirp
			beep(1568, 50);
			warn_flag[idx] = 1;
		}
		crit_flag[idx] = 0;
	} else {
		warn_flag[idx] = 0; crit_flag[idx] = 0;
	}
}

static void check_notifications(void)
{
	notify(N_FOOD, pet.satiety);
	notify(N_FUN,  pet.happy);
	notify(N_ENGY, pet.energy);
	notify(N_WASH, pet.hygiene);
}

// pick the expression frame to draw this instant
static uint8_t current_expression(void)
{
	if (!pet.alive)        return EXP_DEAD;
	if (anim_timer)        return anim_exp;
	if (pet.sleeping)      return EXP_SLEEP;
	if (pet.health < 30 || pet.happy < 25 || pet.satiety < 20)
		return EXP_SAD;
	// idle, with an occasional blink
	if ((frame % 50) < 4)  return EXP_BLINK;
	return EXP_IDLE;
}

// ----------------------------------------------------------------- actions
static void react(uint8_t exp) { anim_exp = exp; anim_timer = ANIM_FRAMES; }

static void do_action(uint8_t act)
{
	switch (act) {
	case ACT_FEED:
		pet.satiety = clamp100(pet.satiety + 30);
		pet.hygiene = clamp100(pet.hygiene - 5);
		react(EXP_EAT);
		beep(880, 60); beep(1175, 80);
		led_blink();
		break;

	case ACT_PLAY:
		if (pet.energy < 15) { beep(220, 120); break; } // too tired
		pet.happy  = clamp100(pet.happy + 25);
		pet.energy = clamp100(pet.energy - 12);
		react(EXP_HAPPY);
		beep(988, 60); beep(1319, 60); beep(1568, 90);
		led_blink();
		break;

	case ACT_SLEEP:
		pet.sleeping = !pet.sleeping;
		beep(pet.sleeping ? 440 : 660, 120);
		break;

	case ACT_CLEAN:
		pet.poop    = 0;
		pet.hygiene = 100;
		pet.happy   = clamp100(pet.happy + 5);
		beep(1319, 50); beep(1047, 50);
		break;

	case ACT_HEAL:
		pet.health = clamp100(pet.health + 35);
		beep(784, 60); beep(1047, 60); beep(1319, 90);
		led_blink();
		break;

	case ACT_STATS:
		screen = SCR_STATS;
		beep(659, 40);
		break;

	case ACT_SETTINGS:
		screen  = SCR_SETTINGS;
		set_sel = 0;
		beep(659, 40);
		break;
	}
}

// ----------------------------------------------------------------- game tick
static void game_tick(void)
{
	pet.age_min++;

	if (pet.sleeping) {
		pet.energy  = clamp100(pet.energy + 6);
		// needs still drift down slowly even while asleep
		pet.satiety = clamp100(pet.satiety - 1);
		if (pet.energy >= 100) pet.sleeping = 0;   // wakes when rested
	} else {
		pet.satiety = clamp100(pet.satiety - 1);
		pet.energy  = clamp100(pet.energy  - 1);
		pet.happy   = clamp100(pet.happy   - 1);
	}

	// hygiene drifts every other tick
	if (pet.age_min & 1) pet.hygiene = clamp100(pet.hygiene - 1);

	// occasional bowel movements (derived from counters, no RNG needed)
	if (!pet.sleeping && pet.poop < 3 &&
	    ((pet.age_min * 7u + frame) & 0x1F) == 0)
		pet.poop++;

	// being dirty / full of poop slowly saps happiness
	if (pet.poop && (pet.age_min & 1)) pet.happy = clamp100(pet.happy - 1);
	if (pet.hygiene < 20 && (pet.age_min & 1)) pet.happy = clamp100(pet.happy - 1);

	// health responds to overall wellbeing
	int8_t lo = pet.satiety;
	if (pet.happy   < lo) lo = pet.happy;
	if (pet.energy  < lo) lo = pet.energy;
	if (pet.hygiene < lo) lo = pet.hygiene;
	if (lo < 15)      pet.health = clamp100(pet.health - 3);
	else if (lo > 50) pet.health = clamp100(pet.health + 2);

	check_notifications();

	if (pet.health <= 0) {
		pet.alive = 0;
		screen = SCR_DEAD;
		beep(330, 200); beep(247, 200); beep(165, 400);
	}
}

// ----------------------------------------------------------------- drawing
static void draw_center_str(int y, const char *s)
{
	int len = 0;
	while (s[len]) len++;
	int x = (SSD1306_W - len * 8) / 2;
	if (x < 0) x = 0;
	ssd1306_drawstr(x, y, s, 1);
}

static void draw_menu_bar(void)
{
	// 7 icons across the bottom (18 px slots), selected one boxed
	for (uint8_t i = 0; i < ICON_COUNT; i++) {
		int x = i * 18 + 1;
		ssd1306_drawImage(x, 48, menu_icons[i], ICON_W, ICON_H, 0);
		if (i == cursor)
			ssd1306_drawRect(x - 1, 47, ICON_W + 1, ICON_H + 1, 1);
	}
}

static void draw_main(void)
{
	ssd1306_setbuf(0);

	// top bar: action label, with a tiny low-health warning
	draw_center_str(0, menu_labels[cursor]);
	if (pet.alive && pet.health < 30 && (frame & 8))
		ssd1306_drawstr(0, 0, "!", 1);
	ssd1306_drawFastHLine(0, 10, SSD1306_W, 1);

	// pet: gentle horizontal stroll + vertical bob (still while asleep)
	int px, py;
	if (pet.sleeping) {
		px = 48; py = 16;
		ssd1306_drawstr(px + PANA_W - 2, 14, "z", 1);
		ssd1306_drawstr(px + PANA_W + 4, 12, "Z", 1);
	} else {
		uint32_t t = frame % 80;
		px = (t < 40) ? 30 + t : 30 + (80 - t);   // 30..70..30
		py = 14 + ((frame % 16) < 8 ? 0 : 1);
	}
	ssd1306_drawImage(px, py, pana_frames[current_expression()],
	                  PANA_W, PANA_H, 0);

	// floor + poop piles
	ssd1306_drawFastHLine(0, 46, SSD1306_W, 1);
	for (uint8_t i = 0; i < pet.poop; i++)
		ssd1306_drawImage(8 + i * 12, 38, spr_poop, 8, 8, 0);

	draw_menu_bar();
	ssd1306_refresh();
}

static void draw_bar(int y, const char *label, int8_t val)
{
	ssd1306_drawstr(0, y, label, 1);
	int bx = 48, bw = 76;
	ssd1306_drawRect(bx, y, bw, 7, 1);
	int fill = (val * (bw - 2)) / 100;
	if (fill > 0) ssd1306_fillRect(bx + 1, y + 1, fill, 5, 1);
}

static void draw_stats(void)
{
	ssd1306_setbuf(0);
	draw_center_str(0, "-- STATUS --");
	draw_bar(10, "FOOD", pet.satiety);
	draw_bar(19, "FUN ", pet.happy);
	draw_bar(28, "ENGY", pet.energy);
	draw_bar(37, "WASH", pet.hygiene);
	draw_bar(46, "HLTH", pet.health);

	char line[17];
	snprintf(line, sizeof(line), "Age %u  %s", pet.age_min,
	         pet.sleeping ? "Zzz" : "");
	ssd1306_drawstr(0, 56, line, 1);
	ssd1306_refresh();
}

static void draw_dead(void)
{
	ssd1306_setbuf(0);
	ssd1306_drawImage(48, 8, spr_grave, 32, 32, 0);
	draw_center_str(44, "R.I.P.");
	char line[17];
	snprintf(line, sizeof(line), "lived %u min", pet.age_min);
	draw_center_str(52, line);
	ssd1306_refresh();
}

static void draw_settings(void)
{
	ssd1306_setbuf(0);
	draw_center_str(0, "- SETTINGS -");
	ssd1306_drawFastHLine(0, 10, SSD1306_W, 1);

	char rows[SETTINGS_ROWS][17];
	snprintf(rows[0], 17, "Screen off:%s", screen_timeout_names[timeout_idx]);
	snprintf(rows[1], 17, "Sound: %s", sound_on ? "On" : "Off");
	snprintf(rows[2], 17, "Back");

	for (uint8_t r = 0; r < SETTINGS_ROWS; r++) {
		int y = 18 + r * 12;
		if (r == set_sel) ssd1306_fillRect(0, y - 1, SSD1306_W, 10, 1);
		// selected row drawn inverted (color 0 on the lit bar)
		ssd1306_drawstr(4, y, rows[r], r == set_sel ? 0 : 1);
	}

	draw_center_str(56, "L/R move  OK use");
	ssd1306_refresh();
}

// ----------------------------------------------------------------- input
typedef struct { uint8_t ok, left, right; } Buttons;

static Buttons read_buttons(void)
{
	// active-low: pressed reads 0
	Buttons b;
	b.ok    = !funDigitalRead(BTN_OK);
	b.left  = !funDigitalRead(BTN_LEFT);
	b.right = !funDigitalRead(BTN_RIGHT);
	return b;
}

// ----------------------------------------------------------------- setup
static void gpio_setup(void)
{
	funGpioInitAll();

	funPinMode(LED_PIN, GPIO_Speed_10MHz | GPIO_CNF_OUT_PP);
	funDigitalWrite(LED_PIN, FUN_LOW);

	funPinMode(BUZZER, GPIO_Speed_10MHz | GPIO_CNF_OUT_PP);
	funDigitalWrite(BUZZER, FUN_LOW);

	// buttons: input with internal pull-up (ODR high selects pull-up)
	funPinMode(BTN_OK,    GPIO_CNF_IN_PUPD);
	funPinMode(BTN_LEFT,  GPIO_CNF_IN_PUPD);
	funPinMode(BTN_RIGHT, GPIO_CNF_IN_PUPD);
	funDigitalWrite(BTN_OK,    FUN_HIGH);
	funDigitalWrite(BTN_LEFT,  FUN_HIGH);
	funDigitalWrite(BTN_RIGHT, FUN_HIGH);
}

static void splash(void)
{
	ssd1306_setbuf(0);
	draw_center_str(4, "PANAGOTCHI");
	ssd1306_drawImage(48, 16, pana_idle, PANA_W, PANA_H, 0);
	draw_center_str(52, "press any key");
	ssd1306_refresh();

	beep(659, 80); beep(784, 80); beep(988, 120);

	// wait until a button is pressed (or ~4 s timeout)
	for (int i = 0; i < 200; i++) {
		Buttons b = read_buttons();
		if (b.ok || b.left || b.right) break;
		Delay_Ms(20);
	}
}

// ----------------------------------------------------------------- main
int main(void)
{
	SystemInit();
	gpio_setup();

	Delay_Ms(120);                 // let the OLED rail settle
	if (ssd1306_i2c_init()) {      // non-zero == failure
		// no display: fall back to a heartbeat blink so the board still shows life
		while (1) { led_blink(); Delay_Ms(700); }
	}
	ssd1306_init();

	pet_reset();
	splash();

	Buttons prev = {0, 0, 0};

	while (1) {
		Buttons b = read_buttons();
		uint8_t ok_edge    = b.ok    && !prev.ok;
		uint8_t left_edge  = b.left  && !prev.left;
		uint8_t right_edge = b.right && !prev.right;
		uint8_t any_edge   = ok_edge | left_edge | right_edge;
		prev = b;

		if (any_edge) idle_frames = 0;

		if (!disp_on) {
			// screen is asleep: the first press only wakes it (not an action)
			if (any_edge) {
				ssd1306_cmd(SSD1306_DISPLAYON);
				disp_on = 1;
			}
		} else {
			switch (screen) {
			case SCR_MAIN:
				if (left_edge) {
					cursor = (cursor + ICON_COUNT - 1) % ICON_COUNT;
					beep(1047, 25);
				}
				if (right_edge) {
					cursor = (cursor + 1) % ICON_COUNT;
					beep(1047, 25);
				}
				if (ok_edge) do_action(cursor);
				draw_main();
				break;

			case SCR_STATS:
				if (any_edge) { screen = SCR_MAIN; beep(880, 30); }
				draw_stats();
				break;

			case SCR_SETTINGS:
				if (left_edge) {
					set_sel = (set_sel + SETTINGS_ROWS - 1) % SETTINGS_ROWS;
					beep(1047, 25);
				}
				if (right_edge) {
					set_sel = (set_sel + 1) % SETTINGS_ROWS;
					beep(1047, 25);
				}
				if (ok_edge) {
					if (set_sel == 0) {       // cycle screen-off timeout
						timeout_idx = (timeout_idx + 1) % TIMEOUT_OPT_COUNT;
						beep(880, 40);
					} else if (set_sel == 1) { // toggle sound
						sound_on = !sound_on;
						beep(988, 60);          // only audible if just enabled
					} else {                   // Back
						screen = SCR_MAIN;
						beep(880, 30);
					}
				}
				draw_settings();
				break;

			case SCR_DEAD:
				if (ok_edge) {            // start a new pet
					pet_reset();
					beep(659, 80); beep(988, 120);
				}
				draw_dead();
				break;
			}

			// sleep the display after the configured idle period
			uint16_t timeout = screen_timeout_opts[timeout_idx];
			if (timeout && idle_frames >= timeout) {
				ssd1306_cmd(SSD1306_DISPLAYOFF);
				disp_on = 0;
			}
		}

		if (anim_timer) anim_timer--;

		// advance game time independent of screen / display state
		if (pet.alive && ++tick_acc >= TICK_FRAMES) {
			tick_acc = 0;
			game_tick();
		}

		frame++;
		idle_frames++;
		Delay_Ms(FRAME_MS);
	}
}