#include <GxEPD2_BW.h>
#include <U8g2_for_Adafruit_GFX.h>
#include <HTTPClient.h>
#include <ArduinoJson.h>

#include "weather-icons.h"
#include "secrets.h"

/* Position for Durlach */
#define lat 48.999
#define lon  8.474

#define FONTSIZE 10
#define SPACING 5

#define DIM(w, h) (((w) << 16) | (h))
#define GETW(dim) ((dim) >> 16)
#define GETH(dim) ((dim) & 0xffff)

extern GxEPD2_GFX_BASE_CLASS &get_display();
extern U8G2_FOR_ADAFRUIT_GFX u8g2Fonts;

static StaticJsonDocument<16000> weather_json;
static DeserializationError json_state = DeserializationError::IncompleteInput;

void fetch_weather() {
	/* use HTTP intentionally for simplicity
	   don't use on insecure networks */
	String url = "http://api.openweathermap.org/data/2.5/onecall?units=metric&lang=de&exclude=minutely,hourly";
	url += "&appid=" + String(openweathermap_apikey);
	url += "&lat=" + String(lat);
	url += "&lon=" + String(lon);

	HTTPClient http;
	http.begin(url);
	int status = http.GET();

	String weather_info = "";
	if (status == HTTP_CODE_OK) {
		weather_info = http.getString();
	} else {
		Serial.println("http error\r\n");
	}
	http.end();
	json_state = deserializeJson(weather_json, weather_info);
	if (json_state != DeserializationError::Ok) {
		Serial.println("json deserialization error\r\n");
	}
}

static uint32_t draw_icon(int16_t x, int16_t y, const unsigned char *image, uint16_t width, uint16_t height) {
	get_display().drawXBitmap(x, y, image, width, height, GxEPD_BLACK);
	return DIM(width, height);
}

static uint32_t draw_weather_icon(int16_t x, int16_t y, int code) {
	const unsigned char *image = NULL;
	uint16_t width = 0, height = 0;

	int icon_group = code / 100;
	switch (icon_group) {
		case 2:
			image = thunderstorm_bits;
			width = thunderstorm_width;
			height = thunderstorm_height;
			break;
		case 3:
		case 5:
			image = rain_bits;
			width = rain_width;
			height = rain_height;
			break;
		case 6:
			image = snow_bits;
			width = snow_width;
			height = snow_height;
			break;
		case 7:
			image = fog_bits;
			width = fog_width;
			height = fog_height;
			break;
		case 8:
			image = cloudy_bits;
			width = cloudy_width;
			height = cloudy_height;
			break;
	}
	if (code == 800 || !image) {
		/* special case, clear sky / no clouds */
		image = sunny_bits;
		width = sunny_width;
		height = sunny_height;
	}

	return draw_icon(x, y, image, width, height);
}

static uint32_t draw_temperature(int16_t x, int16_t y, float temp, float temp_max = 0.0) {
	uint16_t w = thermometer_width, h = thermometer_height;
	int text_width = 0;
	draw_icon(x, y, thermometer_bits, w, h);
	u8g2Fonts.setCursor(x + w + SPACING, y + h/2 + FONTSIZE/2);
	if (temp_max > 0) {
		u8g2Fonts.printf("%.1f - %.1f °C", temp, temp_max);
		text_width = u8g2Fonts.getUTF8Width("88.8 - 88.8 °C");
	} else {
		u8g2Fonts.printf("%.1f °C", temp);
		text_width = u8g2Fonts.getUTF8Width("88.8 °C");
	}

	return DIM(w + SPACING + text_width, h);
}

static uint32_t draw_humidity(int16_t x, int16_t y, int humidity) {
	uint16_t w = humidity_width, h = humidity_height;
	draw_icon(x, y, humidity_bits, w, h);
	u8g2Fonts.setCursor(x + w + SPACING, y + h/2 + FONTSIZE/2);
	u8g2Fonts.printf("%d %%", humidity);

	return DIM(w, h);
}

static uint32_t draw_rain_prob(int16_t x, int16_t y, uint8_t rain) {
	uint16_t w = raindrops_width, h = raindrops_width;
	draw_icon(x, y, raindrops_bits, w, h);
	u8g2Fonts.setCursor(x + w + SPACING, y + h/2 + FONTSIZE/2);
	u8g2Fonts.printf("%d %%", rain);
	int text_width = u8g2Fonts.getUTF8Width("88 %");

	return DIM(w + SPACING + text_width, h);
}

static uint32_t draw_pressure(int16_t x, int16_t y, int pressure) {
	uint16_t w = barometer_width, h = barometer_height;
	draw_icon(x, y, barometer_bits, w, h);
	u8g2Fonts.setCursor(x + w + SPACING, y + h/2 + FONTSIZE/2);
	u8g2Fonts.printf("%d hPa", pressure);

	return DIM(w, h);
}

static uint32_t draw_clouds(int16_t x, int16_t y, int clouds) {
	uint16_t w = cloud_width, h = cloud_height;
	draw_icon(x, y, cloud_bits, w, h);
	u8g2Fonts.setCursor(x + w + SPACING, y + h/2 + FONTSIZE/2);
	u8g2Fonts.printf("%d %%", clouds);
	int text_width = u8g2Fonts.getUTF8Width("88 %");

	return DIM(w + SPACING + text_width, h);
}

static int draw_weather_forecast(int16_t x, int16_t y, const char *title, const JsonObject &json) {
	auto temp_min = json["temp"]["min"].as<float>();
	auto temp_max = json["temp"]["max"].as<float>();
	auto pop = (uint8_t) (100 * json["pop"].as<float>());
	auto cloudiness = json["clouds"].as<int>();
	auto description = json["weather"][0]["description"].as<char *>();

	/* line 1 */
	u8g2Fonts.setFont(u8g2_font_helvB10_tf);
	u8g2Fonts.setCursor(x, y);
	u8g2Fonts.print(title);
	u8g2Fonts.setFont(u8g2_font_helvR10_tf);
	u8g2Fonts.print("  ");
	u8g2Fonts.print(description);

	/* line 2 */
	uint32_t dim = 0;
	y += SPACING;
	dim = draw_temperature(x, y, temp_min, temp_max);
	x += GETW(dim) + SPACING;
	dim = draw_clouds(x, y, cloudiness);
	x += GETW(dim) + SPACING;
	dim = draw_rain_prob(x, y, pop);

	return DIM(0, FONTSIZE + GETH(dim) + 2 * SPACING);
}

void draw_weather(int16_t x0, int16_t y0) {
	if (json_state != DeserializationError::Ok)
		return;

	/* current weather */
	auto current_temp = weather_json["current"]["temp"].as<float>();
	auto current_weather_id = weather_json["current"]["weather"][0]["id"].as<int>();
	auto current_weather_desc = weather_json["current"]["weather"][0]["description"].as<char *>();
	auto current_clouds = weather_json["current"]["clouds"].as<int>();
	auto current_humidity = weather_json["current"]["humidity"].as<int>();
	auto current_pressure = weather_json["current"]["pressure"].as<int>();

	if (!current_weather_desc)
		current_weather_desc = "N/A";

	u8g2Fonts.setFont(u8g2_font_helvR10_tf);

	uint32_t dim = 0;
	int16_t x1 = x0, y1 = y0;
	dim = draw_weather_icon(x0, y0, current_weather_id);
	x1 += GETW(dim) + SPACING;
	y1 += GETH(dim) + SPACING;

	/* line 1 */
	int16_t x = x1, y = y0 + 2 * SPACING;
	uint32_t temp_dim = draw_temperature(x, y, current_temp);
	x += GETW(temp_dim) + 2 * SPACING;
	dim = draw_clouds(x, y, current_clouds);
	y += GETH(dim);

	/* line 2 */
	x = x1;
	dim = draw_humidity(x, y, current_humidity);
	x += GETW(temp_dim) + 2 * SPACING;
	dim = draw_pressure(x, y, current_pressure);
	y += GETH(dim);

	/* forecasts */
	x = x0;
	y = y1;
	dim = draw_weather_forecast(x, y, "Heute:", weather_json["daily"][0]);
	y += GETH(dim);
	dim = draw_weather_forecast(x, y, "Morgen:", weather_json["daily"][1]);
	y += GETH(dim);
	dim = draw_weather_forecast(x, y, "Übermorgen:", weather_json["daily"][2]);
	y += GETH(dim);
}