/*
 * fbdash.c
 *
 * Adapted by Florian Klemenz for use in the fb_dash project
 *
 * Source and all credit goes to 
 * http://raspberrycompote.blogspot.com/
 * -------------------------------------------------------------------------------------------- 
 *
 * http://raspberrycompote.blogspot.ie/2014/03/low-level-graphics-on-raspberry-pi-part_14.html
 *
 * Original work by J-P Rosti (a.k.a -rst- and 'Raspberry Compote')
 *
 * Licensed under the Creative Commons Attribution 3.0 Unported License
 * (http://creativecommons.org/licenses/by/3.0/deed.en_US)
 *
 * Distributed in the hope that this will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 *
 */


#include <stdlib.h>
#include <stdio.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <float.h>

#include <mysql.h>

#include "fblib.h"

#define WIDTH 240
#define HEIGHT 320


char *fbp = 0;

struct s_color {
    unsigned char r;
    unsigned char g;
    unsigned char b;
};
typedef struct s_color color;

struct s_sourcedata {
	char* text;
	char* temperature;
	char* humidity;
};
typedef struct s_sourcedata sourcedata;


void finish_with_error(MYSQL *con) {
  fprintf(stderr, "%s\n", mysql_error(con));
  mysql_close(con);
  exit(1);
}

void updateSlot(char *fbp, sourcedata data, int x_offset, int y_offset, color c) {
	render_string(fbp, ubuntu_mono_24, data.text, x_offset, y_offset, c.r, c.g, c.b);
	
	render_string(fbp, ubuntu_mono_48, data.temperature, x_offset + 115, y_offset - 9, c.r, c.g, c.b);
	render_string(fbp, ubuntu_mono_48, "C", x_offset + 195, y_offset - 9, c.r, c.g, c.b);
	
	render_string(fbp, ubuntu_mono_48, data.humidity, x_offset + 115, y_offset + 26, c.r, c.g, c.b);
	render_string(fbp, ubuntu_mono_48, "%", x_offset + 195, y_offset + 26, c.r, c.g, c.b);
}

void updateData(char *fbp, int slot_height) {
	// query database for latest values
    printf("MySQL client version: %s\n", mysql_get_client_info());
	MYSQL *con = mysql_init(NULL);
	if (con == NULL) {
		fprintf(stderr, "%s\n", mysql_error(con));
		exit(1);
	}
	if (mysql_real_connect(con, "web-pi", "grafanaReader", "grafanaReader", "grafanaData", 0, NULL, 0) == NULL) {
		fprintf(stderr, "%s\n", mysql_error(con));
		mysql_close(con);
		exit(1);
	}
	char* query = "\
SELECT \
  time, \
  source, \
  metric, \
  value \
FROM readings AS r \
INNER JOIN sources AS s ON r.source_id = s.id \
INNER JOIN metrics AS m ON r.metric_id = m.id \
WHERE \
  time > (NOW() - 60 * 15) AND \
  metric IN ('Luftfeuchte','Temperatur') AND \
  source IN ('Esszimmer','Wohnzimmer', 'Schlafzimmer', 'Abstellkammer') \
ORDER BY time DESC \
LIMIT 100;";

    //printf("%s\n",query);
    printf("Fetching data ...\n");

	if (mysql_query(con, query)) {
		finish_with_error(con);
	}
	MYSQL_RES *result = mysql_store_result(con);
	if (result == NULL) {
		finish_with_error(con);
	}

    // define what to display
    sourcedata data[4] = {
	    { "Esszimmer", NULL, NULL  },
    	{ "Wohnzimmer", NULL, NULL },
        { "Schlafzimmer", NULL, NULL },
        { "Abstellkammer", NULL, NULL }
    };
	
	int num_fields = mysql_num_fields(result);
  	if (num_fields > 3) {
        MYSQL_ROW row;
        while ((row = mysql_fetch_row(result))) {
            if (strlen(row[3]) > 4) row[3][4] = '\0'; // loose the secnod and third decimal ...

            // data binding
            for (int i = 0; i < 4; i++) {
                if (strcmp(row[1], data[i].text) == 0) {
                    if (strcmp(row[2], "Temperatur") == 0 && data[i].temperature == NULL) data[i].temperature = row[3];
                    else if (strcmp(row[2], "Luftfeuchte") == 0 && data[i].humidity == NULL) data[i].humidity = row[3];	
                }
            }

            // debugging
            //for(int i = 0; i < num_fields; i++) printf("%s ", row[i] ? row[i] : "NULL");
            //printf("\n");
        }
    }

    printf("Updating dashboard...\n");
    for (int i = 0; i < 4; i++) {
        color c = {255,125 + 25*i,25 + 25*i};
        updateSlot(fbp, data[i], 15, 7 + slot_height * i, c);
    }


    printf("Done!\n");

  	mysql_free_result(result);
	mysql_close(con);

}




void draw() {
    clear_screen(fbp);

    // horizontal spacersint x_space = 10;
    int y_step_width = HEIGHT / 4;
    for (int i = 1; i < 4; i++) {
        int x0 = 15;
        int x1 = WIDTH - x0;
        int y = y_step_width * i;

        int r = 225;
        int g = 32;
        int b = 32;
        
        draw_line(fbp, x0, y-1, x1, y-1, r, g, b);
        draw_line(fbp, x0, y  , x1, y  , r, g, b);
        draw_line(fbp, x0, y+1, x1, y+1, r, g, b);
    }

    // fetch data from database and update screen 
	updateData(fbp, y_step_width);
}


// application entry point
int main(int argc, char* argv[])
{
    int fbfd = 0;
    long int screensize = 0;

    // Open the framebuffer file for reading and writing
    fbfd = open("/dev/fb1", O_RDWR);
    if (fbfd == -1) {
        printf("Error: cannot open framebuffer device.\n");
        return(1);
    }
    printf("The framebuffer device was opened successfully.\n");

    // map fb to user mem 
    screensize = WIDTH*HEIGHT*2;
    fbp = (char*)mmap(0, 
              screensize, 
              PROT_READ | PROT_WRITE, 
              MAP_SHARED, 
              fbfd, 
              0);

    if ((int)fbp == -1) {
        printf("Failed to mmap.\n");
    }
    else {
        // draw...
        draw();
    }

    // cleanup
    //clear_screen(fbp);
    munmap(fbp, screensize);
    close(fbfd);

    return 0;
}