#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <GL/glut.h>

void afficher(void);
int initWindow(int, char**, void(*)(void));
void destroyWindow(int);
long getFileSize(FILE*);
void parseFile(char*, long);
bool charger(char*);
void printCourbeTerminal(void);
void ligne(int);
float map(float, float, float, float, float);

// Variables donneés
#define MAXC  20
#define MAXV 100

float	courbe[MAXC][MAXV];
float	valmin[MAXC];
float	valmax[MAXC];
int		nc = 0;


float map(float smin, float smax, float val, float omin, float omax)
{
	float percent = (val - smin) / (smax - smin);
	//printf("v%f, p%f, min%f, max%f\n", val, percent, omin, omax);
	return (omax-omin) * percent + omin;
}

void ligne(int index)
{
	if(index >= nc)
	{
		printf("Courbe non-existante.");
		return;
	}

	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(-1.0,1.0,-1.0,1.0,-1.0,1.0);
	glColor3f(1.0,1.0,1.0);
	glBegin(GL_LINE_STRIP);

	unsigned int size = (unsigned int)courbe[index][0];

	for(unsigned int i = 1; i < size; i++)
	{
		float pos_x = map(0, size, i-1, -1.0, 1.0);
		float pos_y = map(valmin[index], valmax[index], courbe[index][i], -1.0, 1.0);
		glVertex2f(pos_x, pos_y);
		//printf("%d : {%f, %f}\n", i, pos_x, pos_y);
	}

	fflush(stdout);

	glEnd();
}

void afficher(void)
{
	glClearColor(0.0,0.0,0.0,0.0);	
	glClear(GL_COLOR_BUFFER_BIT);

	ligne(0);

	glFlush();
}

int initWindow(int argc, char* argv[], void(*display)(void))
{
	int vx1 = 0, vx2 = 400, vy1 = 0, vy2 = 400;

	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_SINGLE|GLUT_RGBA);
	glutInitWindowPosition(vx1, vy1);
	glutInitWindowSize(vx2, vy2);

	int window = glutCreateWindow("TP1");

	glutDisplayFunc(display);

	return window;
}

void destroyWindow(int window)
{
	glutDestroyWindow(window);
}

long getFileSize(FILE* file)
{
	fseek(file, 0, SEEK_END);
	long fileSize = ftell(file);
	rewind(file);
	return fileSize;
}

void parseFile(char* file, long size)
{
	nc = atoi(file);
	printf("nc=%d\n", nc);

	printf("====\n%s\n====\n", file);

	// Pointeur mobile dans le fichier
	char* pointeur = file;
	unsigned int line = 0;
	while(line < nc+1)
	{
		/* Cherche le premier \n à partir du pointeur
		 * /!\ on suppose un fichier encodé en UNIX (LF) /!\ */
		pointeur = strchr(pointeur, '\n') + 1;
//		printf(" ->\"%c\"", *pointeur);

		int taille_tableau = atoi(pointeur);
		courbe[line][0] = taille_tableau;
//		printf(" ->\"%d\" \n", taille_tableau);

		// On suppose que les nombres sont séparés par un espace
		for(unsigned int i = 1; i < taille_tableau; i++)
		{
			pointeur = strchr(pointeur, ' ') + 1;
			float num = strtof(pointeur, 0);
			courbe[line][i] = num;

			if(i == 1)
			{
				valmin[line] = num;
				valmax[line] = num;
			}else{
				if(num < valmin[line])
					valmin[line] = num;

				if(num > valmax[line])
					valmax[line] = num;
			}
		}
		line++;
	}

}

bool charger(char* nom)
{
	FILE* file = fopen(nom, "r");
	if(file == NULL)
	{
		printf("Erreur ouverture fichier.\n");
		return false;
	}

	long fileSize = getFileSize(file);

	char* buffer = (char*)malloc(sizeof(char) * fileSize + 1);
	if(buffer == NULL)
	{
		printf("Erreur allocation mémoire.\n");
		return false;
	}
	buffer[fileSize] = 0; // NULL à la fin du fichier
	
	int res = fread(buffer, sizeof(char), fileSize, file);
	if(res == 0)
	{
		printf("Erreur lecture fichier.\n");
		return false;
	}

	fclose(file);

	parseFile(buffer, fileSize);

	free(buffer);

	return true;
}

void printCourbeTerminal(void)
{
	for(unsigned int i = 0; i < MAXC; i++)
	{
		for(unsigned int j = 0; j < MAXV; j++)
		{
			printf("%f", courbe[i][j]);
			if(j < MAXV-1)
				printf(", ");
		}
		printf("\n");
	}
}

int main(int argc, char* argv[])
{
	if(!charger("valeurs.txt"))
		return EXIT_FAILURE;

	//printCourbeTerminal();

	int window = initWindow(argc, argv, afficher);

	glutMainLoop();

	destroyWindow(window);
	return EXIT_SUCCESS;
}