#include "util.hpp"

using namespace std;

bool read_file(string* s, const char* filepath) {
    ifstream file(filepath);
    if (!file.is_open()) {
        return false;
    }
    *s = { istreambuf_iterator<char>(file), istreambuf_iterator<char>() };
    return true;
}

vector<string> split_str(string s, char delim) {
    vector<string> res;
    string cur_word;
    istringstream ss(s);
    while (getline(ss, cur_word, delim)) {
        res.push_back(cur_word);
    }
    return res;
}

// https://songho.ca/opengl/gl_quaternion.html
glm::mat4 quat_to_mat4(glm::quat q) {
    glm::vec4 col0 = glm::vec4(
        1 - 2 * q.y * q.y - 2 * q.z * q.z, 2 * q.x * q.y + 2 * q.w * q.z, 2 * q.x * q.z - 2 * q.w * q.y, 0);

    glm::vec4 col1 = glm::vec4(
        2 * q.x * q.y - 2 * q.w * q.z, 1 - 2 * q.x * q.x - 2 * q.z * q.z, 2 * q.y * q.z + 2 * q.w * q.x, 0);

    glm::vec4 col2 = glm::vec4(
        2 * q.x * q.z + 2 * q.w * q.y, 2 * q.y * q.z - 2 * q.w * q.x, 1 - 2 * q.x * q.x - 2 * q.y * q.y, 0);

    glm::vec4 col3 = glm::vec4(0, 0, 0, 1);

    return glm::mat4(col0, col1, col2, col3);
}

float randf() { return (float)abs(rand()) / (float)RAND_MAX; }