//! ----------------------------------------------------
//! `🗲` Vulkan Shader `🗲`
//! ----------------------------------------------------

const std = @import("std");
const vk = @import("vulkan");
const gtl = @import("gtl");
const Device = @import("device.zig");
const Self = @This();

//
// FIELDS
//

raw: vk.VkShaderModule,
device: *const Device,

/// ----------------------------------------------------
/// ----------------------------------------------------
pub fn init(
    spv_path: []const u8,
    device: *const Device,
    alloc: std.mem.Allocator,
    io: std.Io,
) !Self {
    const code = try readFile(spv_path, alloc, io);
    defer alloc.free(code);

    const module = try createModule(
        code,
        device,
    );

    return .{
        .raw = module,
        .device = device,
    };
}

/// ----------------------------------------------------
/// ----------------------------------------------------
pub fn deinit(self: *Self) void {
    if (self.raw) |raw| {
        vk.vkDestroyShaderModule(self.device.raw, raw, null);
        self.raw = null;
    }
}

/// ----------------------------------------------------
/// Helper
/// ----------------------------------------------------
fn createModule(
    code: []u8,
    device: *const Device,
) !*vk.VkShaderModule_T {
    var create_info: vk.VkShaderModuleCreateInfo = .{
        .sType = vk.VK_STRUCTURE_TYPE_SHADER_MODULE_CREATE_INFO,
        .pCode = @ptrCast(@alignCast(code.ptr)),
        .codeSize = code.len,
    };

    var module: vk.VkShaderModule = null;
    if (vk.vkCreateShaderModule(device.raw, &create_info, null, &module) != vk.VK_SUCCESS) {
        return error.FailedToCreateShaderModule;
    }

    return module.?;
}

/// ----------------------------------------------------
/// Helper
/// ----------------------------------------------------
fn readFile(
    path: []const u8,
    alloc: std.mem.Allocator,
    io: std.Io,
) ![]u8 {
    return std.Io.Dir.cwd().readFileAlloc(io, path, alloc, .unlimited) catch |err| {
        gtl.log.err("{s}: {s}\n", .{ @errorName(err), path }, null);
        return err;
    };
}