local options_file = arg[1]

local opt_fd = assert(io.open(options_file, 'w'))

local w = function(s)
  if s:match('^    %.') then
    opt_fd:write(s .. ',\n')
  else
    opt_fd:write(s .. '\n')
  end
end

--- @module 'nvim.options'
local options = require('options')

local cstr = options.cstr

local redraw_flags = {
  ui_option = 'kOptFlagUIOption',
  tabline = 'kOptFlagRedrTabl',
  statuslines = 'kOptFlagRedrStat',
  current_window = 'kOptFlagRedrWin',
  current_buffer = 'kOptFlagRedrBuf',
  all_windows = 'kOptFlagRedrAll',
  curswant = 'kOptFlagCurswant',
  highlight_only = 'kOptFlagHLOnly',
}

local list_flags = {
  comma = 'kOptFlagComma',
  onecomma = 'kOptFlagOneComma',
  commacolon = 'kOptFlagComma|kOptFlagColon',
  onecommacolon = 'kOptFlagOneComma|kOptFlagColon',
  flags = 'kOptFlagFlagList',
  flagscomma = 'kOptFlagComma|kOptFlagFlagList',
}

--- @param s string
--- @return string
local lowercase_to_titlecase = function(s)
  return s:sub(1, 1):upper() .. s:sub(2)
end

--- @param o vim.option_meta
--- @return string
local function get_flags(o)
  --- @type string
  local flags = '0'

  --- @param f string
  local add_flag = function(f)
    flags = flags .. '|' .. f
  end

  if o.list then
    add_flag(list_flags[o.list])
  end
  if o.redraw then
    for _, r_flag in ipairs(o.redraw) do
      add_flag(redraw_flags[r_flag])
    end
  end
  if o.expand then
    add_flag('kOptFlagExpand')
    if o.expand == 'nodefault' then
      add_flag('kOptFlagNoDefExp')
    end
  end
  for _, flag_desc in ipairs({
    { 'nodefault', 'NoDefault' },
    { 'no_mkrc', 'NoMkrc' },
    { 'secure' },
    { 'gettext' },
    { 'noglob', 'NoGlob' },
    { 'normal_fname_chars', 'NFname' },
    { 'normal_dname_chars', 'NDname' },
    { 'pri_mkrc', 'PriMkrc' },
    { 'deny_in_modelines', 'NoML' },
    { 'deny_duplicates', 'NoDup' },
    { 'modelineexpr', 'MLE' },
    { 'func' },
  }) do
    local key_name = flag_desc[1]
    local def_name = 'kOptFlag' .. (flag_desc[2] or lowercase_to_titlecase(key_name))
    if o[key_name] then
      add_flag(def_name)
    end
  end
  return flags
end

--- @param opt_type vim.option_type
--- @return string
local function opt_type_enum(opt_type)
  return ('kOptValType%s'):format(lowercase_to_titlecase(opt_type))
end

--- @param o vim.option_meta
--- @return string
local function get_type_flags(o)
  local opt_types = (type(o.type) == 'table') and o.type or { o.type }
  local type_flags = '0'
  assert(type(opt_types) == 'table')

  for _, opt_type in ipairs(opt_types) do
    assert(type(opt_type) == 'string')
    type_flags = ('%s | (1 << %s)'):format(type_flags, opt_type_enum(opt_type))
  end

  return type_flags
end

--- @param c string|string[]
--- @param base_string? string
--- @return string
local function get_cond(c, base_string)
  local cond_string = base_string or '#if '
  if type(c) == 'table' then
    cond_string = cond_string .. get_cond(c[1], '')
    for i, subc in ipairs(c) do
      if i > 1 then
        cond_string = cond_string .. ' && ' .. get_cond(subc, '')
      end
    end
  elseif c:sub(1, 1) == '!' then
    cond_string = cond_string .. '!defined(' .. c:sub(2) .. ')'
  else
    cond_string = cond_string .. 'defined(' .. c .. ')'
  end
  return cond_string
end

--- @param s string
--- @return string
local static_cstr_as_string = function(s)
  return ('{ .data = %s, .size = sizeof(%s) - 1 }'):format(s, s)
end

--- @param v vim.option_value|function
--- @return string
local get_opt_val = function(v)
  --- @type vim.option_type
  local v_type

  if type(v) == 'function' then
    v, v_type = v() --[[ @as string, vim.option_type ]]

    if v_type == 'string' then
      v = static_cstr_as_string(v)
    end
  else
    v_type = type(v) --[[ @as vim.option_type ]]

    if v_type == 'boolean' then
      v = v and 'true' or 'false'
    elseif v_type == 'number' then
      v = ('%iL'):format(v)
    elseif v_type == 'string' then
      v = static_cstr_as_string(cstr(v))
    end
  end

  return ('{ .type = %s, .data.%s = %s }'):format(opt_type_enum(v_type), v_type, v)
end

--- @param d vim.option_value|function
--- @param n string
--- @return string

local get_defaults = function(d, n)
  if d == nil then
    error("option '" .. n .. "' should have a default value")
  end
  return get_opt_val(d)
end

--- @type [string,string][]
local defines = {}

--- @param i integer
--- @param o vim.option_meta
local function dump_option(i, o)
  w('  [' .. ('%u'):format(i - 1) .. ']={')
  w('    .fullname=' .. cstr(o.full_name))
  if o.abbreviation then
    w('    .shortname=' .. cstr(o.abbreviation))
  end
  w('    .flags=' .. get_flags(o))
  w('    .type_flags=' .. get_type_flags(o))
  if o.enable_if then
    w(get_cond(o.enable_if))
  end

  if o.varname then
    w('    .var=&' .. o.varname)
  elseif o.immutable then
    -- Immutable options can directly point to the default value.
    w(('    .var=&options[%u].def_val.data'):format(i - 1))
  elseif #o.scope == 1 and o.scope[1] == 'window' then
    w('    .var=VAR_WIN')
  else
    -- Option must be immutable or have a variable.
    assert(false)
  end
  w('    .immutable=' .. (o.immutable and 'true' or 'false'))
  if #o.scope == 1 and o.scope[1] == 'global' then
    w('    .indir=PV_NONE')
  else
    assert(#o.scope == 1 or #o.scope == 2)
    assert(#o.scope == 1 or o.scope[1] == 'global')
    local min_scope = o.scope[#o.scope]
    local varname = o.pv_name or o.varname or ('p_' .. (o.abbreviation or o.full_name))
    local pv_name = (
      'OPT_'
      .. min_scope:sub(1, 3):upper()
      .. '('
      .. (min_scope:sub(1, 1):upper() .. 'V_' .. varname:sub(3):upper())
      .. ')'
    )
    if #o.scope == 2 then
      pv_name = 'OPT_BOTH(' .. pv_name .. ')'
    end
    table.insert(defines, { 'PV_' .. varname:sub(3):upper(), pv_name })
    w('    .indir=' .. pv_name)
  end
  if o.cb then
    w('    .opt_did_set_cb=' .. o.cb)
  end
  if o.expand_cb then
    w('    .opt_expand_cb=' .. o.expand_cb)
  end
  if o.enable_if then
    w('#else')
    -- Hidden option directly points to default value.
    w(('    .var=&options[%u].def_val.data'):format(i - 1))
    -- Option is always immutable on the false branch of `enable_if`.
    w('    .immutable=true')
    w('    .indir=PV_NONE')
    w('#endif')
  end
  if o.defaults then
    if o.defaults.condition then
      w(get_cond(o.defaults.condition))
    end
    w('    .def_val=' .. get_defaults(o.defaults.if_true, o.full_name))
    if o.defaults.condition then
      if o.defaults.if_false then
        w('#else')
        w('    .def_val=' .. get_defaults(o.defaults.if_false, o.full_name))
      end
      w('#endif')
    end
  else
    w('    .def_val=NIL_OPTVAL')
  end
  w('  },')
end

w([[
#include "nvim/ex_docmd.h"
#include "nvim/ex_getln.h"
#include "nvim/insexpand.h"
#include "nvim/mapping.h"
#include "nvim/ops.h"
#include "nvim/option.h"
#include "nvim/optionstr.h"
#include "nvim/quickfix.h"
#include "nvim/runtime.h"
#include "nvim/tag.h"
#include "nvim/window.h"

static vimoption_T options[] = {]])
for i, o in ipairs(options.options) do
  dump_option(i, o)
end
w('};')
w('')

for _, v in ipairs(defines) do
  w('#define ' .. v[1] .. ' ' .. v[2])
end