const builtin = @import("builtin");

pub fn magic(a: u64, b: u64) [4]u64 {
    return .{ 0xc7b1dd30df4c8b88, 0x0a82e883a194f07b, a, b };
}

pub const BaseRevision = extern struct {
    id: [2]u64 = .{ 0xf9562b2d5c95a6c8, 0x6a7b384944536bdc },
    revision: u64,

    pub fn is_supported(self: *const volatile @This()) bool {
        return self.revision == 0;
    }
};

pub const BootloaderInfo = struct {
    pub const Request = extern struct {
        id: [4]u64 = magic(0xf55038d8e2a1202f, 0x279426fcf5f59740),
        revision: u64 = 0,
        response: ?*Response = null,
    };

    pub const Response = extern struct {
        revision: u64,
        name: [*:0]u8,
        version: [*:0]u8,
    };
};

pub const BootTime = struct {
    pub const Request = extern struct {
        id: [4]u64 = magic(0x502746e184c088aa, 0xfbc5ec83e6327893),
        revision: u64 = 0,
        response: ?*Response = null,
    };

    pub const Response = extern struct {
        revision: u64,
        boot_time: i64,
    };
};

pub const File = extern struct {
    revision: u64,
    address: [*]u8,
    size: u64,
    path: [*:0]u8,
    cmdline: [*:0]u8,
    media_type: MediaType,
    unused: u32,
    tftp_ip: u32,
    tftp_port: u32,
    partition_index: u32,
    mbr_disk_id: u32,
    gpt_disk_uuid: Uuid,
    gpt_part_uuid: Uuid,
    part_uuid: Uuid,

    pub const Uuid = extern struct {
        a: u32,
        b: u16,
        c: u16,
        d: [8]u8,
    };

    pub const MediaType = enum(u32) {
        generic = 0,
        optical = 1,
        tftp = 2,
    };
};

pub const Framebuffer = extern struct {
    address: [*]u8,
    width: u64,
    height: u64,
    pitch: u64,
    bpp: u16,
    memory_model: MemoryModel,
    red_mask_size: u8,
    red_mask_shift: u8,
    green_mask_size: u8,
    green_mask_shift: u8,
    blue_mask_size: u8,
    blue_mask_shift: u8,
    unused: [7]u8,
    edid_size: u64,
    edid: ?[*]u8,

    // Response revision 1
    mode_count: u64,
    modes: [*]*VideoMode,

    pub const MemoryModel = enum(u8) {
        rgb = 1,
    };

    pub const VideoMode = extern struct {
        pitch: u64,
        width: u64,
        height: u64,
        bpp: u16,
        memory_model: MemoryModel,
        red_mask_size: u8,
        red_mask_shift: u8,
        green_mask_size: u8,
        green_mask_shift: u8,
        blue_mask_size: u8,
        blue_mask_shift: u8,
    };
    
    pub const Request = extern struct {
        id: [4]u64 = magic(0x9d5827dcd881dd75, 0xa3148604f6fab11b),
        revision: u64 = 1,
        response: ?*Response = null
    };

    pub const Response = extern struct {
        revision: u64,
        framebuffer_count: u64,
        framebuffers: [*]*Framebuffer,

        pub inline fn getFramebuffers(self: *@This()) []*Framebuffer {
            return self.framebuffers[0..self.framebuffer_count];
        }
    };

    pub inline fn getEdid(self: *@This()) ?[]u8 {
        if (self.edid) |edid| {
            return edid[0..self.edid_size];
        }
    }

    pub inline fn getModes(self: *@This()) []*VideoMode {
        return self.modes[0..self.mode_count];
    }
};

pub const Hhdm = struct {
    pub const Request = extern struct {
        id: [4]u64 = magic(0x48dcf1cb8ad2b852, 0x63984e959a98244b),
        revision: u64 = 0,
        response: ?*Response = null,
    };

    pub const Response = extern struct {
        revision: u64,
        offset: u64,
    };
};

pub const Rsdp = struct {
    pub const Request = extern struct {
        id: [4]u64 = magic(0xc5e77b6b397e7b43, 0x27637845accdcf3c),
        revision: u64 = 0,
        response: ?*Response = null,
    };

    pub const Response = extern struct {
        revision: u64,
        address: u64,
    };
};

pub const MemoryMap = struct {
    pub const Request = extern struct {
        id: [4]u64 = magic(0x67cf3d9d378a806f, 0xe304acdfc50c3c62),
        revision: u64 = 0,
        response: ?*Response = null,
    };

    pub const Response = extern struct {
        revision: u64,
        entry_count: u64,
        entries: [*]*Entry,

        pub inline fn getEntries(self: *@This()) []*Entry {
            return self.entries[0..self.entry_count];
        }
    };

    pub const Entry = extern struct {
        base: u64,
        length: u64,
        type: EntryType,
    };
    
    pub const EntryType = enum(u64) {
        usable = 0,
        reserved = 1,
        acpi_reclaimable = 2,
        acpi_nvs = 3,
        bad_memory = 4,
        bootloader_reclaimable = 5,
        kernel_and_modules = 6,
        framebuffer = 7,
    };
};

pub const Paging = struct {
    pub const Mode = switch (builtin.cpu.arch) {
        .aarch64, .x86_64 => enum(u64) {
            four_level,
            five_level,

            pub inline fn default() Mode {
                return Mode.four_level;
            }

            pub inline fn max() Mode {
                return Mode.five_level;
            }

            pub inline fn min() Mode {
                return Mode.four_level;
            }
        },
        .loongarch64 => enum(u64) {
            four_level,

            pub inline fn default() Mode {
                return Mode.four_level;
            }

            pub inline fn max() Mode {
                return Mode.four_level;
            }

            pub inline fn min() Mode {
                return Mode.four_level;
            }
        },
        .riscv64 => enum(u64) {
            sv39,
            sv48,
            sv57,

            pub inline fn default() Mode {
                return Mode.sv48;
            }

            pub inline fn max() Mode {
                return Mode.sv57;
            }

            pub inline fn min() Mode {
                return Mode.sv39;
            }
        },
        else => |x| @compileError("Unsupported architecture: " ++ @tagName(x)),
    };

    pub const Request = extern struct {
        id: [4]u64 = magic(0x95c1a0edab0944cb, 0xa4e5cb3842f7488a),
        revision: u64 = 0,
        response: ?*Response = null,
        mode: Mode = .default(),

        // Revision 1+
        max_mode: Mode = .max(),
        min_mode: Mode = .min(),
    };

    pub const Response = extern struct {
        revision: u64,
        mode: Mode
    };
};

pub const DeviceTreeBlob = struct {
    pub const Request = extern struct {
        id: [4]u64 = magic(0xb40ddb48fb54bac7, 0x545081493f81ffb7),
        revision: u64 = 0,
        response: ?*Response = null,
    };

    pub const Response = extern struct {
        revision: u64,
        pointer: ?*anyopaque,
    };
};