--- Capture current highlights as a baseline for comparison.
--- Stores both gui (hex) and cterm values where available.
--- Usage: :luafile tests/manual/capture_highlights.lua
--- Output: /tmp/nugu_highlights_baseline.txt

local function rgb_to_hex(n)
  if type(n) ~= 'number' then return nil end
  return string.format('#%06x', n)
end

local function sorted_keys(t)
  local keys = {}
  for k in pairs(t) do
    keys[#keys + 1] = k
  end
  table.sort(keys)
  return keys
end

local all_hl = vim.api.nvim_get_hl(0, {})
local names = sorted_keys(all_hl)

local lines = {
  '-- Nugu highlight baseline',
  '-- Date: ' .. os.date '!%Y-%m-%dT%H:%M:%SZ',
  '-- Groups: ' .. #names,
  '-- termguicolors: ' .. tostring(vim.o.termguicolors),
  '',
}

for _, name in ipairs(names) do
  local hl = all_hl[name]
  local parts = {}

  if hl.fg          then parts[#parts + 1] = 'fg=' .. rgb_to_hex(hl.fg) end
  if hl.bg          then parts[#parts + 1] = 'bg=' .. rgb_to_hex(hl.bg) end
  if hl.sp          then parts[#parts + 1] = 'sp=' .. rgb_to_hex(hl.sp) end
  if hl.ctermfg     then parts[#parts + 1] = 'ctermfg=' .. hl.ctermfg end
  if hl.ctermbg     then parts[#parts + 1] = 'ctermbg=' .. hl.ctermbg end
  if hl.blend       then parts[#parts + 1] = 'blend=' .. hl.blend end

  -- check both top-level (gui) and cterm table for attributes
  local cterm = hl.cterm or {}
  if hl.bold   or cterm.bold           then parts[#parts + 1] = 'bold' end
  if hl.italic or cterm.italic         then parts[#parts + 1] = 'italic' end
  if hl.underline   or cterm.underline   then parts[#parts + 1] = 'underline' end
  if hl.undercurl   or cterm.undercurl   then parts[#parts + 1] = 'undercurl' end
  if hl.underdouble or cterm.underdouble then parts[#parts + 1] = 'underdouble' end
  if hl.underdotted or cterm.underdotted then parts[#parts + 1] = 'underdotted' end
  if hl.underdashed or cterm.underdashed then parts[#parts + 1] = 'underdashed' end
  if hl.strikethrough or cterm.strikethrough then parts[#parts + 1] = 'strikethrough' end
  if hl.reverse     or cterm.reverse     then parts[#parts + 1] = 'reverse' end
  if hl.standout    or cterm.standout    then parts[#parts + 1] = 'standout' end
  if hl.nocombine   or cterm.nocombine   then parts[#parts + 1] = 'nocombine' end

  if hl.link        then parts[#parts + 1] = 'link=' .. hl.link end
  if hl.default     then parts[#parts + 1] = 'default' end

  if #parts > 0 then
    lines[#lines + 1] = name .. ' ' .. table.concat(parts, ' ')
  end
end

local outpath = vim.fn.argv()[1] or '/tmp/nugu_highlights_baseline.txt'
local f = assert(io.open(outpath, 'w'))
f:write(table.concat(lines, '\n') .. '\n')
f:close()
print('Captured ' .. #names .. ' highlight groups to ' .. outpath)