local fmt = require("elf.fmt")

---@alias Magic [integer, integer, integer, integer]

---@class Header
---@field magic Magic
---@field class Class
---@field data Endian
---@field ident_version integer
---@field osabi Osabi
---@field abiversion integer
---@field type Type
---@field machine Machine
---@field version integer
---@field entry integer
---@field phoff integer
---@field shoff integer
---@field flags integer
---@field ehsize integer
---@field phentsize? integer
---@field phnum? integer
---@field shentsize integer
---@field shnum integer
---@field shstrndx integer
local M = {}

---@param hdr Header
---@return string
---@nodiscard
function M.pack(hdr)
    return string.pack("BBBBBBBBBxxxxxxx" ..
        fmt.endian(hdr.data) ..
        "I2I2I4" ..
        string.rep(fmt.word(hdr.class), 3) ..
        "I4I2I2I2I2I2I2",
        hdr.magic[1], hdr.magic[2], hdr.magic[3], hdr.magic[4],
        hdr.class,
        hdr.data,
        hdr.ident_version,
        hdr.osabi,
        hdr.abiversion,
        hdr.type,
        hdr.machine,
        hdr.version,
        hdr.entry,
        hdr.phoff,
        hdr.shoff,
        hdr.flags,
        hdr.ehsize,
        hdr.phentsize,
        hdr.phnum,
        hdr.shentsize,
        hdr.shnum,
        hdr.shstrndx)
end

return M