//
// Created by Tristan on 10/16/2025.
//

#include "camera.h"
#include "../..//core/logger/log.h"

void camera_init(Camera *self, vec3 initial_position, int width, int height) {
    // copy initial_pos vector
    glm_vec3_copy(initial_position, self->Position);

    // initialize orientation vector
    glm_vec3_copy((vec3){0.0f, 0.0f, -1.0f}, self->Orientation);

    // initialize up vector
    glm_vec3_copy((vec3){0.0f, 1.0f, 0.0f}, self->Up);

    // initialize controls and viewport
    self->speed = 0.1f;
    self->sensitivity = 100.0f;
    self->FOV_deg = 45.0f;

    self->width = width;
    self->height = height;

    // Init view matrix to identity (for first frame)
    glm_mat4_identity(self->View);
}

/*
Camera l_camera = {
    .Position = { 0.0f, 0.0f, 0.0f },
    .Orientation = { 0.0f, 0.0f, -1.0f },
    .Up = { 0.0f, 1.0f, 0.0f }
};*/

void camera_update_view_matrix(Camera *self) {
    // calc the center or target point (Pos + Orientation)
    vec3 target;
    glm_vec3_add(self->Position, self->Orientation, target);

    // create view matrix
    glm_lookat(self->Position, target, self->Up, self->View);
}

void camera_update_projection(Camera *self, float nearPlane, float farPlane, mat4 dest) {
    float aspect = (float)self->width / (float)self->height;
    glm_perspective(glm_rad(self->FOV_deg), aspect, nearPlane, farPlane, dest);
}

// TODO: Update matrix function signature to accept camera entity?
// change name to camera_upload_matrix for clarity?
void camera_matrix_to_shader(Camera *self, GLuint shader_program_ID, const char *uniform_name) {
    // update the view matrix first, camera position might have moved
    camera_update_view_matrix(self);

    // calculate projection matrix (P) with temporary matrix 'projection' for the result
    mat4 projection;
    camera_update_projection(self, 0.1f, 100.0f, projection);

    // combine the matrices -- P * V -> PV
    mat4 view_projection;
    glm_mat4_mul(projection, self->View, view_projection);

    // get uniform location
    GLint uniform_location = glGetUniformLocation(shader_program_ID, uniform_name);

    if (uniform_location == -1) {
        log_error("Warning: Uniform '%s' not found in shader program %u.\n", uniform_name, shader_program_ID);
        return;
    }

    // upload combined matrix to the shader
    // view_projection[0] array pointer decays to first value
    glUniformMatrix4fv(uniform_location, 1, GL_FALSE, view_projection[0]);
}

void camera_inputs(Camera *self, SDL_Event *event) {
    // TODO: implementation for handling keyboard/mouse inputs for camera
}