Skin_Vertex :: struct {
	bone_index: [4] float;
	bone_weight: [4] float;
}

Mesh_Vertex_Data_Type :: enum {
    NONE;
    POSITION;
    NORMAL;
    TEXCOORD;
    TANGENT;
    COLOR;
    BITANGENT;
    BONE_INDICES;
    BONE_WEIGHTS;

    INSTANCED_MAT1;
    INSTANCED_MAT2;
    INSTANCED_MAT3;
    INSTANCED_MAT4;
}

Mesh_Handle :: #type, distinct u32;

Mesh :: struct {
    name        : string;
    positions   : [..] Vector3;
    normals     : [..] Vector3;
    texcoords   : [..] Vector2;
    tangents    : [..] Vector3;
    bitangents  : [..] Vector3;
    colors      : [..] Vector4;
    skin_data   : [..] Skin_Vertex;

	bone_indices: [..] s32;
	bone_matrices: [..] Matrix4;
	num_bones: s32;

    indices     : [..] u32;
    ib          : Buffer_Handle;

    vbs         : Table(u32, Buffer_Handle);
    //vb          : Buffer_Handle;
}

get_mesh_vb :: (mesh: *Mesh, pipeline_handle: Pipeline_State_Handle = 0) -> Buffer_Handle {
    handle := ifx pipeline_handle == 0 then engine.renderer.current_state.last_set_pipeline else pipeline_handle;

    pipeline_state := *engine.renderer.pipeline_states[handle-1];
    return get_mesh_vb(mesh, pipeline_state.mesh_data_types);
}

get_mesh_vb :: (mesh: *Mesh, input: [] Mesh_Vertex_Data_Type) -> Buffer_Handle {
    hash : u32 = 0;

    nums : [8] u32 : .[13, 61, 84, 86, 65, 10000, 100000, 126];
    for input, i: input {
        hash += nums[i] * cast(u32)input;
    }

    if !table_contains(*mesh.vbs, hash) {
        final_vertices : [..] float;
        final_vertices.allocator = temp;

        stride : u32 = 0;

        for input: input {
            if input == {
                case .POSITION; stride += 3;
                case .NORMAL; stride += 3;
                case .TEXCOORD; stride += 2;
                case .COLOR; stride += 4;
                case .TANGENT; stride += 3;
                case .BITANGENT; stride += 3;
                case .BONE_INDICES; stride += 4;
                case .BONE_WEIGHTS; stride += 4;
            }
        }

        for 0..mesh.positions.count-1 {
            for input: input {
                if input == {
                    case .POSITION; {
                        array_add(*final_vertices, mesh.positions[it].x);
                        array_add(*final_vertices, mesh.positions[it].y);
                        array_add(*final_vertices, mesh.positions[it].z);
                    }
                    case .NORMAL; {
                        if mesh.normals.count > 0 {
                            array_add(*final_vertices, mesh.normals[it].x);
                            array_add(*final_vertices, mesh.normals[it].y);
                            array_add(*final_vertices, mesh.normals[it].z);
                        } else {
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            log_error("Mesh didn't have required normals\n");
                        }
                    }
                    case .TEXCOORD; {
                        if mesh.texcoords.count > 0 {
                            array_add(*final_vertices, mesh.texcoords[it].x);
                            array_add(*final_vertices, mesh.texcoords[it].y);
                        } else {
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            log_error("Mesh didn't have required texcoords\n");
                        }
                    }
                    case .COLOR; {
                        if mesh.colors.count > 0 {
                            array_add(*final_vertices, mesh.colors[it].x);
                            array_add(*final_vertices, mesh.colors[it].y);
                            array_add(*final_vertices, mesh.colors[it].z);
                            array_add(*final_vertices, mesh.colors[it].w);
                        } else {
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            log_error("Mesh didn't have required colors\n");
                        }
                    }
                    case .TANGENT; {
                        if mesh.tangents.count > 0 {
                            array_add(*final_vertices, mesh.tangents[it].x);
                            array_add(*final_vertices, mesh.tangents[it].y);
                            array_add(*final_vertices, mesh.tangents[it].z);
                        } else {
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            log_error("Mesh didn't have required tangents\n");
                        }
                    }
                    case .BITANGENT; {
                        if mesh.bitangents.count > 0 {
                            array_add(*final_vertices, mesh.bitangents[it].x);
                            array_add(*final_vertices, mesh.bitangents[it].y);
                            array_add(*final_vertices, mesh.bitangents[it].z);
                        } else {
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            log_error("Mesh didn't have required bitangents\n");
                        }
                    }
                    case .BONE_INDICES; {
                        if mesh.skin_data.count > 0 {
                            for index: 0..3 {
                                array_add(*final_vertices, mesh.skin_data[it].bone_index[index]);
                            }
                        } else {
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            log_error("Mesh didn't have required bone indices\n");
                        }
                    }
                    case .BONE_WEIGHTS; {
                        if mesh.skin_data.count > 0 {
                            for index: 0..3 {
                                array_add(*final_vertices, mesh.skin_data[it].bone_weight[index]);
                            }
                        } else {
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            array_add(*final_vertices, 0.0);
                            log_error("Mesh didn't have required bone weights\n");
                        }
                    }
                }
            }
        }

        vb_size := size_of(float)*stride*mesh.positions.count;
        vb := create_vertex_buffer(engine.renderer, final_vertices.data, xx vb_size, stride=size_of(float)*stride);
        table_add(*mesh.vbs, hash, vb);
    }

    value, success := table_find(*mesh.vbs, hash);
    return value;
}

delete_mesh :: (handle: Mesh_Handle) {
    mesh := parray_get(*engine.renderer.meshes, handle);
    for mesh.vbs {
        destroy_buffer(engine.renderer, it);
    }

    deinit(*mesh.vbs);

    parray_remove(*engine.renderer.meshes, handle);
}