#include "terrain.h"
#include "_internal/private_terrain.h"

#include "block.h"
#include "chunk.h"

#include "raylib.h"

#include <math.h>

/**
 * Iterates through every coordinate in a chunk, calculating terrain height 
 * and cave presence to populate the block data array.
 */
void generate_terrain(struct chunk_struct *chunk, struct chunk_position_struct* chunks_world_position)
{
        // Align world position to integers once
        int32_t base_x = chunks_world_position->x;
        int32_t base_y = chunks_world_position->y;
        int32_t base_z = chunks_world_position->z;

        for (uint8_t x = 0; x < chunk_size; x++)
        {
                for (uint8_t z = 0; z < chunk_size; z++)
                {
                        int32_t world_coordinate_x = base_x + x;
                        int32_t world_coordinate_z = base_z + z;
                        int32_t surface_height = 
                                (int32_t)floorf(
                                        _get_terrain_height_at_coordinates(
                                                                world_coordinate_x, 
                                                                world_coordinate_z));

                        for (uint8_t y = 0; y < chunk_size; y++)
                        {
                                int32_t world_coordinate_y = base_y + y;
                                uint8_t resulting_block_id = block_air;

                                if (world_coordinate_y <= surface_height)
                                {
                                        resulting_block_id = block_dirt;

                                        if (world_coordinate_y < surface_height - 3)
                                        {
                                                resulting_block_id = block_stone;
                                        }

                                        if (world_coordinate_y > surface_height - 1)
                                        {
                                                resulting_block_id = block_grass;
                                        }

                                        if (_is_cave_present_at_coordinates(
                                                world_coordinate_x,
                                                world_coordinate_y,
                                                world_coordinate_z,
                                                surface_height))
                                        {
                                                resulting_block_id = block_air;
                                        }
                                }
                                
                                chunk->block_data[index_chunk(x, y, z)] = resulting_block_id;
                        }
                }
        }
}