// normalization program

/*
	Usage:
	normalize [min=5] [max=50]
	given values are in %
*/

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

int min = 0;
int max = 100;

float factor; // factor to use on input to get output

short maxValue = 0;

typedef struct {
	short channel[2];
	void * next; // pointer to node
} node;

int main(int argc, char ** argv) {
	int leido;		
	int i;
	
	for (i = 1; i < argc; i++) {
		// go through arguments
		char * argument = argv[i];
		// min
		if (strstr(argument, "min") == argument) {
			// minimo
			if (argument[3] != '=' || argument[4] == ' ') {
				fprintf(stderr, "El minimo se debe establecer \"min=valor\"\n");
				exit(1);
			}
			min = atoi(&(argument[4]));
			
			if (min < 0) {
				fprintf(stderr, "El minimo no puede ser menor que 0!\n");
				exit(1);
			}
			if (min > 100) {
				fprintf(stderr, "El minimo no puede ser mayor que 100!\n");
				exit(1);
			}
		} else if (strstr(argument, "max") == argument) {
			// maximo
			if (argument[3] != '=' || argument[4] == ' ') {
				fprintf(stderr, "El maximo se debe establecer \"max=valor\"\n");
				exit(1);
			}
			max = atoi(&(argument[4]));
			
			if (max < 0) {
				fprintf(stderr, "El maximo no puede ser menor que 0!\n");
				exit(1);
			}
			if (max > 100) {
				fprintf(stderr, "El maximo no puede ser mayor que 100!\n");
				exit(1);
			}
		}
	}
	
	if (min > max) {
		fprintf(stderr, "El minimo no puede ser mayor que el maximo!\n");
		exit(1);
	}
	
	fprintf(stderr, "Niveles usados: min=%d max=%d\n", min, max); 
	
	node * newNode;
	node list;
	list.next = NULL;
	node * lastNode;

	do {
		newNode = (node *) malloc(sizeof(node));
		leido = fread(newNode, 1, 4, stdin);
		if (leido == 4) {
			newNode->next = NULL;
			for (i = 0; i < 2; i++) {
				short channel = newNode->channel[i];
				if (abs(channel) > maxValue) {
					maxValue = abs(channel);
					fprintf(stderr, "New Max Value = %d (%d)\n", maxValue, channel);
				}
			}
			if (list.next == NULL) {
				list.next = (void *) newNode;
			} else {
				lastNode->next = (void *) newNode;
			}
			lastNode = newNode;
		} else {
			// calculo del factor
			float nivelMaximo = (float) maxValue / 0x7fff * 100;
			fprintf(stderr, "nivel alcanzado: %f\n", nivelMaximo);
			factor = 1;
			
			if (nivelMaximo < min) {
				factor = (float) min / nivelMaximo;
			}
			
			if (nivelMaximo > max)  {
				factor = (float) max / nivelMaximo;
				//fprintf(stderr, "cambie el maximo\n");
			}
				
			fprintf(stderr, "Factor usado: %f\n", factor);
			// se termino el flujo
			lastNode = list.next;
			while (lastNode != NULL)  {
				// process list
				//printf("%c%c", (short) (lastNode->channel[0]*0.5), (short) (lastNode->channel[1]*0.5));
				lastNode -> channel[0] *= factor;
				lastNode -> channel[1] *= factor;
				fwrite(lastNode, 1, 4, stdout);
				newNode = lastNode;
				lastNode = lastNode -> next;
				free(newNode); // release memory from node already used
			}
			if (leido != 0) {
				printf("Parece que el flujo de entrada no correspondiera a un flujo de 16 bits por canal de 2 canales :(\n");
			}
		}
	} while (leido == 4);
}