#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include "types.h"

/* Returns EOF on when reading end of file. */
int
read_line(FILE *f, char *buf, size_t n)
{
    char c;
    size_t byte_count = 0;
    while ((c = fgetc(f)) != '\n') {
        if (c == EOF) {
            buf++;
            *buf = '\0';
            return EOF;
        }
        else if (byte_count == n) {
            break;
        }
        else {
            *buf = c;
            buf++;
            byte_count++;
        }
    }
    *buf = '\0';
    return 0;
}

vec3 *
read_vertices(char *path, uint32_t *vertex_num_out)
{
    FILE *in = fopen(path, "r");

    vec3 *vertex_out = malloc(sizeof(vec3));
    *vertex_num_out = 0;

    #define BUFSIZE 256
    char buf[BUFSIZE];

    int status;
    do {
        memset(buf, 0, BUFSIZE);
        status = read_line(in, buf, BUFSIZE);
        if (buf[0] == 'v' && buf[1] == ' ') {
            /* ugly imperative garbage, look away */
            vec3 v;

            #define VERTBUFSIZE 32
            char vertbuf[VERTBUFSIZE];
            size_t i, start = 2;
            for (i = start; buf[i] != ' '; i++) {
                vertbuf[i-start] = buf[i];
            }
            vertbuf[i] = '\0';
            v.x = atof(vertbuf);

            memset(vertbuf, 0, VERTBUFSIZE);

            i++;
            start = i;
            for (; buf[i] != ' '; i++) {
                vertbuf[i-start] = buf[i];
            }
            vertbuf[i] = '\0';
            v.y = atof(vertbuf);

            memset(vertbuf, 0, VERTBUFSIZE);

            i++;
            start = i;
            for (; buf[i] != '\0'; i++) {
                vertbuf[i-start] = buf[i];
            }
            vertbuf[i] = '\0';
            v.z = atof(vertbuf);

            /* put the new vertex into the array */
            *vertex_num_out += 1;
            vertex_out = realloc(vertex_out, sizeof(vec3) * (*vertex_num_out));
            vertex_out[*vertex_num_out - 1] = v;
        }
    } while(status != EOF);

    fclose(in);

    return vertex_out;
}

uint32_t *
read_indices(char *path, uint32_t *index_num_out)
{
    FILE *in = fopen(path, "r");

    uint32_t *index_out = malloc(sizeof(uint32_t));
    *index_num_out = 0;

#define BUFSIZE 256
    char buf[BUFSIZE];

    int status;
    do {
        memset(buf, 0, BUFSIZE);
        status = read_line(in, buf, BUFSIZE);
        if (buf[0] == 'f' && buf[1] == ' ') {
#define INDEXBUFSIZE 32
            char indexbuf[INDEXBUFSIZE] = {0};
            size_t i, start = 2;

            for (i = start; buf[i] != '/'; i++) {
                indexbuf[i-start] = buf[i];
            }
            indexbuf[i] = '\0';
            uint32_t a = atoi(indexbuf);
            for (; buf[i] != ' '; i++);
            i++;
            memset(indexbuf, 0, INDEXBUFSIZE);

            start = i;
            for (; buf[i] != '/'; i++) {
                indexbuf[i-start] = buf[i];
            }
            indexbuf[i] = '\0';
            uint32_t b = atoi(indexbuf);
            for (; buf[i] != ' '; i++);
            i++;
            memset(indexbuf, 0, INDEXBUFSIZE);

            start = i;
            for (; buf[i] != '/'; i++) {
                indexbuf[i-start] = buf[i];
            }
            indexbuf[i] = '\0';
            uint32_t c = atoi(indexbuf);

            /* put the new index into the array */
            *index_num_out += 3;
            index_out = realloc(index_out, sizeof(uint32_t) * (*index_num_out));
            index_out[*index_num_out - 3] = a-1;
            index_out[*index_num_out - 2] = b-1;
            index_out[*index_num_out - 1] = c-1;
        }
    } while(status != EOF);

    fclose(in);

    return index_out;
}

int
main(int argc, char *argv[])
{
    if (argc != 3) {
        fprintf(stderr, "usage: serialize in.obj out.mod");
        exit(1);
    }

    /* convert obj to mod */
    uint32_t vertices_num;
    uint32_t indices_num;
    vec3 *vertices = read_vertices(argv[1], &vertices_num);
    uint32_t *indices = read_indices(argv[1], &indices_num);

    /* serialize the data */
    FILE *f = fopen(argv[2], "w");

    fwrite(&vertices_num, 4, 1, f);

    for (size_t i = 0; i < vertices_num; i++) {
        fwrite(&vertices[i].x, 8, 1, f);
        fwrite(&vertices[i].y, 8, 1, f);
        fwrite(&vertices[i].z, 8, 1, f);
    }

    fwrite(&indices_num, 4, 1, f);

    for (size_t i = 0; i < indices_num; i++) {
        fwrite(&indices[i], 4, 1, f);
    }

    fclose(f);

    free(vertices);
    free(indices);
}