#include<stdio.h>
#include<stdlib.h>
#include<fcntl.h>
#include<unistd.h>
#define STB_IMAGE_WRITE_IMPLEMENTATION
#define STB_IMAGE_IMPLEMENTATION
#include<stb/stb_image.h>
#include<stb/stb_image_write.h>
#include<sys/time.h>
#include<pthread.h>
#include "scolor.h"


unsigned char mortar_threshold = 160;
size_t array_length;
unsigned char *image;
int width, height;

pthread_mutex_t tge_mutex = PTHREAD_MUTEX_INITIALIZER;
unsigned long total_green_extra = 0;

struct limits {
	size_t start;
	size_t stop;
};
void* apply_filter(void* p){
	struct limits *l = p;
	size_t center_x = width/2, center_y = height/2;
	unsigned long tge_local = 0;
	printf("Starting at %lu, stopping at %lu\n", l->start, l->stop);
	for(size_t i = l->start; i < l->stop; i += 3){
		unsigned char red = image[i];
		unsigned char green = image[i + 1];
		unsigned char blue = image[i + 2];
		unsigned char rb_average = (red / 2 + blue / 2);
		unsigned char green_extra = 0;
		if(green > rb_average)
			green_extra = green - rb_average;
		tge_local += green_extra;
	}
	pthread_mutex_lock(&tge_mutex);
	total_green_extra += tge_local;
	pthread_mutex_unlock(&tge_mutex);
}

double timediff(struct timeval* start, struct timeval* end) {
	double s_diff = end->tv_sec - start->tv_sec;
	double us_diff = end->tv_usec - start->tv_usec;
	s_diff += us_diff / 1000000;
	return s_diff;
}

int main(int argc, char ** argv){
	if(argc == 1)
		image = stbi_load("brick.jpg", &width, &height, 0, 3); 
	else {
		image = stbi_load(argv[1], &width, &height, 0, 3); 
		if(!image){
			printf(RED("%s:  Did not load\n"), argv[1]);
			return 1;
		}
	}

	array_length = width * height * 3; // 3 channels
	if(!image)
		puts(RED("No image, giving up!"));
	else
		printf(PURPLE("Image size:  %d by %d\n"), width, height);

	struct timeval start, end;
	gettimeofday(&start, NULL);
	int thread_count = 32;
	pthread_t threads[thread_count];
	struct limits parameters[thread_count];
	for(int i = 0; i < thread_count; i++){
		parameters[i].start = i * (array_length / thread_count);
		parameters[i].stop = (i + 1) * (array_length / thread_count);
		pthread_create(&threads[i], 0, apply_filter, &parameters[i]);
	}
	for(int i = 0; i < thread_count; i++){
		pthread_join(threads[i], 0);
	}
	gettimeofday(&end, NULL);
	printf("Green count time: %lf\n",  timediff(&start, &end));		

	printf(DGREEN("Total Green Extra: ")DBLUE(" %lu\n"), total_green_extra);
	printf(DGREEN("Greenness Score: ")DBLUE(" %.2lf\n"), (double)total_green_extra / (width * height));

	return 0;
}