/*
 * Copyright (c) 2018 Phytec Messtechnik GmbH
 * Copyright (c) 2018 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/display/cfb.h>
#include <zephyr/sys/printk.h>
#include <zephyr/drivers/flash.h>
#include <zephyr/storage/flash_map.h>
#include <zephyr/drivers/sensor.h>

#include <string.h>
#include <stdio.h>

#include <zephyr/bluetooth/bluetooth.h>
#include <zephyr/bluetooth/mesh/access.h>

#include "mesh.h"
#include "board.h"

#define STORAGE_PARTITION		storage_partition
#define STORAGE_PARTITION_DEV		FIXED_PARTITION_DEVICE(STORAGE_PARTITION)
#define STORAGE_PARTITION_OFFSET	FIXED_PARTITION_OFFSET(STORAGE_PARTITION)
#define STORAGE_PARTITION_SIZE		FIXED_PARTITION_SIZE(STORAGE_PARTITION)

enum font_size {
	FONT_SMALL = 0,
	FONT_MEDIUM = 1,
	FONT_BIG = 2,
};

enum screen_ids {
	SCREEN_MAIN = 0,
	SCREEN_SENSORS = 1,
	SCREEN_STATS = 2,
	SCREEN_LAST,
};

struct font_info {
	uint8_t columns;
} fonts[] = {
	[FONT_BIG] =    { .columns = 12 },
	[FONT_MEDIUM] = { .columns = 16 },
	[FONT_SMALL] =  { .columns = 25 },
};

#define LONG_PRESS_TIMEOUT K_SECONDS(1)

#define STAT_COUNT 128

static const struct device *const epd_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_display));
static bool pressed;
static uint8_t screen_id = SCREEN_MAIN;
static struct k_work_delayable epd_work;
static struct k_work_delayable long_press_work;
static char str_buf[256];

static const struct gpio_dt_spec leds[] = {
	GPIO_DT_SPEC_GET(DT_ALIAS(led0), gpios),
	GPIO_DT_SPEC_GET(DT_ALIAS(led1), gpios),
	GPIO_DT_SPEC_GET(DT_ALIAS(led2), gpios),
};

static const struct gpio_dt_spec sw0_gpio = GPIO_DT_SPEC_GET(DT_ALIAS(sw0), gpios);

struct k_work_delayable led_timer;

static size_t print_line(enum font_size font_size, int row, const char *text,
			 size_t len, bool center)
{
	uint8_t font_height, font_width;
	uint8_t line[fonts[FONT_SMALL].columns + 1];
	int pad;

	cfb_framebuffer_set_font(epd_dev, font_size);

	len = MIN(len, fonts[font_size].columns);
	memcpy(line, text, len);
	line[len] = '\0';

	if (center) {
		pad = (fonts[font_size].columns - len) / 2U;
	} else {
		pad = 0;
	}

	cfb_get_font_size(epd_dev, font_size, &font_width, &font_height);

	if (cfb_print(epd_dev, line, font_width * pad, font_height * row)) {
		printk("Failed to print a string\n");
	}

	return len;
}

static size_t get_len(enum font_size font, const char *text)
{
	const char *space = NULL;
	size_t i;

	for (i = 0; i <= fonts[font].columns; i++) {
		switch (text[i]) {
		case '\n':
		case '\0':
			return i;
		case ' ':
			space = &text[i];
			break;
		default:
			continue;
		}
	}

	/* If we got more characters than fits a line, and a space was
	 * encountered, fall back to the last space.
	 */
	if (space) {
		return space - text;
	}

	return fonts[font].columns;
}

void board_blink_leds(void)
{
	k_work_reschedule(&led_timer, K_MSEC(100));
}

void board_show_text(const char *text, bool center, k_timeout_t duration)
{
	int i;

	cfb_framebuffer_clear(epd_dev, false);

	for (i = 0; i < 3; i++) {
		size_t len;

		while (*text == ' ' || *text == '\n') {
			text++;
		}

		len = get_len(FONT_BIG, text);
		if (!len) {
			break;
		}

		text += print_line(FONT_BIG, i, text, len, center);
		if (!*text) {
			break;
		}
	}

	cfb_framebuffer_finalize(epd_dev);

	if (!K_TIMEOUT_EQ(duration, K_FOREVER)) {
		k_work_reschedule(&epd_work, duration);
	}
}

static struct stat {
	uint16_t addr;
	char name[9];
	uint8_t min_hops;
	uint8_t max_hops;
	uint16_t hello_count;
	uint16_t heartbeat_count;
} stats[STAT_COUNT] = {
	[0 ... (STAT_COUNT - 1)] = {
		.min_hops = BT_MESH_TTL_MAX,
		.max_hops = 0,
	},
};

static uint32_t stat_count;

#define NO_UPDATE -1

static int add_hello(uint16_t addr, const char *name)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(stats); i++) {
		struct stat *stat = &stats[i];

		if (!stat->addr) {
			stat->addr = addr;
			strncpy(stat->name, name, sizeof(stat->name) - 1);
			stat->hello_count = 1U;
			stat_count++;
			return i;
		}

		if (stat->addr == addr) {
			/* Update name, incase it has changed */
			strncpy(stat->name, name, sizeof(stat->name) - 1);

			if (stat->hello_count < 0xffff) {
				stat->hello_count++;
				return i;
			}

			return NO_UPDATE;
		}
	}

	return NO_UPDATE;
}

static int add_heartbeat(uint16_t addr, uint8_t hops)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(stats); i++) {
		struct stat *stat = &stats[i];

		if (!stat->addr) {
			stat->addr = addr;
			stat->heartbeat_count = 1U;
			stat->min_hops = hops;
			stat->max_hops = hops;
			stat_count++;
			return i;
		}

		if (stat->addr == addr) {
			if (hops < stat->min_hops) {
				stat->min_hops = hops;
			} else if (hops > stat->max_hops) {
				stat->max_hops = hops;
			}

			if (stat->heartbeat_count < 0xffff) {
				stat->heartbeat_count++;
				return i;
			}

			return NO_UPDATE;
		}
	}

	return NO_UPDATE;
}

void board_add_hello(uint16_t addr, const char *name)
{
	uint32_t sort_i;

	sort_i = add_hello(addr, name);
	if (sort_i != NO_UPDATE) {
	}
}

void board_add_heartbeat(uint16_t addr, uint8_t hops)
{
	uint32_t sort_i;

	sort_i = add_heartbeat(addr, hops);
	if (sort_i != NO_UPDATE) {
	}
}

static void show_statistics(void)
{
	int top[4] = { -1, -1, -1, -1 };
	int len, i, line = 0;
	struct stat *stat;
	char str[32];

	cfb_framebuffer_clear(epd_dev, false);

	len = snprintk(str, sizeof(str),
		       "Own Address: 0x%04x", mesh_get_addr());
	print_line(FONT_SMALL, line++, str, len, false);

	len = snprintk(str, sizeof(str),
		       "Node Count:  %u", stat_count + 1);
	print_line(FONT_SMALL, line++, str, len, false);

	/* Find the top sender */
	for (i = 0; i < ARRAY_SIZE(stats); i++) {
		int j;

		stat = &stats[i];
		if (!stat->addr) {
			break;
		}

		if (!stat->hello_count) {
			continue;
		}

		for (j = 0; j < ARRAY_SIZE(top); j++) {
			if (top[j] < 0) {
				top[j] = i;
				break;
			}

			if (stat->hello_count <= stats[top[j]].hello_count) {
				continue;
			}

			/* Move other elements down the list */
			if (j < ARRAY_SIZE(top) - 1) {
				memmove(&top[j + 1], &top[j],
					((ARRAY_SIZE(top) - j - 1) *
					 sizeof(top[j])));
			}

			top[j] = i;
			break;
		}
	}

	if (stat_count > 0) {
		len = snprintk(str, sizeof(str), "Most messages from:");
		print_line(FONT_SMALL, line++, str, len, false);

		for (i = 0; i < ARRAY_SIZE(top); i++) {
			if (top[i] < 0) {
				break;
			}

			stat = &stats[top[i]];

			len = snprintk(str, sizeof(str), "%-3u 0x%04x %s",
				       stat->hello_count, stat->addr,
				       stat->name);
			print_line(FONT_SMALL, line++, str, len, false);
		}
	}

	cfb_framebuffer_finalize(epd_dev);
}

static void show_sensors_data(k_timeout_t interval)
{
	struct sensor_value val[3];
	uint8_t line = 0U;
	uint16_t len = 0U;

	cfb_framebuffer_clear(epd_dev, false);

	/* hdc1010 */
	if (get_hdc1010_val(val)) {
		goto _error_get;
	}

	len = snprintf(str_buf, sizeof(str_buf), "Temperature:%d.%d C\n",
		       val[0].val1, val[0].val2 / 100000);
	print_line(FONT_SMALL, line++, str_buf, len, false);

	len = snprintf(str_buf, sizeof(str_buf), "Humidity:%d%%\n",
		       val[1].val1);
	print_line(FONT_SMALL, line++, str_buf, len, false);

	/* mma8652 */
	if (get_mma8652_val(val)) {
		goto _error_get;
	}

	len = snprintf(str_buf, sizeof(str_buf), "AX :%10.3f\n",
		       sensor_value_to_double(&val[0]));
	print_line(FONT_SMALL, line++, str_buf, len, false);

	len = snprintf(str_buf, sizeof(str_buf), "AY :%10.3f\n",
		       sensor_value_to_double(&val[1]));
	print_line(FONT_SMALL, line++, str_buf, len, false);

	len = snprintf(str_buf, sizeof(str_buf), "AZ :%10.3f\n",
		       sensor_value_to_double(&val[2]));
	print_line(FONT_SMALL, line++, str_buf, len, false);

	/* apds9960 */
	if (get_apds9960_val(val)) {
		goto _error_get;
	}

	len = snprintf(str_buf, sizeof(str_buf), "Light :%d\n", val[0].val1);
	print_line(FONT_SMALL, line++, str_buf, len, false);
	len = snprintf(str_buf, sizeof(str_buf), "Proximity:%d\n", val[1].val1);
	print_line(FONT_SMALL, line++, str_buf, len, false);

	cfb_framebuffer_finalize(epd_dev);

	k_work_reschedule(&epd_work, interval);

	return;

_error_get:
	printk("Failed to get sensor data or print a string\n");
}

static void show_main(void)
{
	char buf[CONFIG_BT_DEVICE_NAME_MAX];
	int i;

	strncpy(buf, bt_get_name(), sizeof(buf) - 1);
	buf[sizeof(buf) - 1] = '\0';

	/* Convert commas to newlines */
	for (i = 0; buf[i] != '\0'; i++) {
		if (buf[i] == ',') {
			buf[i] = '\n';
		}
	}

	board_show_text(buf, true, K_FOREVER);
}

static void epd_update(struct k_work *work)
{
	switch (screen_id) {
	case SCREEN_STATS:
		show_statistics();
		return;
	case SCREEN_SENSORS:
		show_sensors_data(K_SECONDS(2));
		return;
	case SCREEN_MAIN:
		show_main();
		return;
	}
}

static void long_press(struct k_work *work)
{
	/* Treat as release so actual release doesn't send messages */
	pressed = false;
	screen_id = (screen_id + 1) % SCREEN_LAST;
	printk("Change screen to id = %d\n", screen_id);
	board_refresh_display();
}

static bool button_is_pressed(void)
{
	return gpio_pin_get_dt(&sw0_gpio) > 0;
}

static void button_interrupt(const struct device *dev,
			     struct gpio_callback *cb,
			     uint32_t pins)
{
	if (button_is_pressed() == pressed) {
		return;
	}

	pressed = !pressed;
	printk("Button %s\n", pressed ? "pressed" : "released");

	if (pressed) {
		k_work_reschedule(&long_press_work, LONG_PRESS_TIMEOUT);
		return;
	}

	k_work_cancel_delayable(&long_press_work);

	if (!mesh_is_initialized()) {
		return;
	}

	/* Short press for views */
	switch (screen_id) {
	case SCREEN_SENSORS:
	case SCREEN_STATS:
		return;
	case SCREEN_MAIN:
		if (pins & BIT(sw0_gpio.pin)) {
			uint32_t uptime = k_uptime_get_32();
			static uint32_t bad_count, press_ts;

			if (uptime - press_ts < 500) {
				bad_count++;
			} else {
				bad_count = 0U;
			}

			press_ts = uptime;

			if (bad_count) {
				if (bad_count > 5) {
					mesh_send_baduser();
					bad_count = 0U;
				} else {
					printk("Ignoring press\n");
				}
			} else {
				mesh_send_hello();
			}
		}
		return;
	default:
		return;
	}
}

static int configure_button(void)
{
	static struct gpio_callback button_cb;

	if (!gpio_is_ready_dt(&sw0_gpio)) {
		printk("%s: device not ready.\n", sw0_gpio.port->name);
		return -ENODEV;
	}

	gpio_pin_configure_dt(&sw0_gpio, GPIO_INPUT);

	gpio_pin_interrupt_configure_dt(&sw0_gpio, GPIO_INT_EDGE_BOTH);

	gpio_init_callback(&button_cb, button_interrupt, BIT(sw0_gpio.pin));

	gpio_add_callback(sw0_gpio.port, &button_cb);

	return 0;
}

int set_led_state(uint8_t id, bool state)
{
	return gpio_pin_set_dt(&leds[id], state);
}

static void led_timeout(struct k_work *work)
{
	static int led_cntr;
	int i;

	/* Disable all LEDs */
	for (i = 0; i < ARRAY_SIZE(leds); i++) {
		set_led_state(i, 0);
	}

	/* Stop after 5 iterations */
	if (led_cntr >= (ARRAY_SIZE(leds) * 5)) {
		led_cntr = 0;
		return;
	}

	/* Select and enable current LED */
	i = led_cntr++ % ARRAY_SIZE(leds);
	set_led_state(i, 1);

	k_work_reschedule(&led_timer, K_MSEC(100));
}

static int configure_leds(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(leds); i++) {
		if (!gpio_is_ready_dt(&leds[i])) {
			printk("%s: device not ready.\n", leds[i].port->name);
			return -ENODEV;
		}

		gpio_pin_configure_dt(&leds[i], GPIO_OUTPUT_INACTIVE);
	}

	k_work_init_delayable(&led_timer, led_timeout);
	return 0;
}

static int erase_storage(void)
{
	const struct device *dev = STORAGE_PARTITION_DEV;

	if (!device_is_ready(dev)) {
		printk("Flash device not ready\n");
		return -ENODEV;
	}

	return flash_erase(dev, STORAGE_PARTITION_OFFSET, STORAGE_PARTITION_SIZE);
}

void board_refresh_display(void)
{
	k_work_reschedule(&epd_work, K_NO_WAIT);
}

int board_init(void)
{
	if (!device_is_ready(epd_dev)) {
		printk("%s: device not ready.\n", epd_dev->name);
		return -ENODEV;
	}

	if (cfb_framebuffer_init(epd_dev)) {
		printk("Framebuffer initialization failed\n");
		return -EIO;
	}

	cfb_framebuffer_clear(epd_dev, true);

	if (configure_button()) {
		printk("Failed to configure button\n");
		return -EIO;
	}

	if (configure_leds()) {
		printk("LED init failed\n");
		return -EIO;
	}

	k_work_init_delayable(&epd_work, epd_update);
	k_work_init_delayable(&long_press_work, long_press);

	pressed = button_is_pressed();
	if (pressed) {
		printk("Erasing storage\n");
		board_show_text("Resetting Device", false, K_SECONDS(4));
		erase_storage();
	}

	return 0;
}