-- /bin/ls - Lists files in a directory.
--
-- Iterate over the 'children' map exposed via C++.

local function format_permissions(perms)
  local rwx = { "-", "-", "-", "-", "-", "-", "-", "-", "-" }
  if(perms & 0x100) ~= 0 then rwx[1] = "r" end -- Owner read.
  if(perms & 0x080) ~= 0 then rwx[2] = "w" end -- Owner write.
  if(perms & 0x040) ~= 0 then rwx[3] = "x" end -- Owner execute.
  if(perms & 0x020) ~= 0 then rwx[4] = "r" end -- Group read.
  if(perms & 0x010) ~= 0 then rwx[5] = "w" end -- Group write.
  if(perms & 0x008) ~= 0 then rwx[6] = "x" end -- Group execute.
  if(perms & 0x004) ~= 0 then rwx[7] = "r" end -- Other read.
  if(perms & 0x002) ~= 0 then rwx[8] = "w" end -- Other write.
  if(perms & 0x001) ~= 0 then rwx[9] = "x" end -- Other execute.
  return table.concat(rwx)
end

local function get_username_from_uid(uid)
  local passwd_content = bettola.read_file(context, "/etc/passwd")
  for line in passwd_content:gmatch("(^\n]+)") do
    local parts = {}
    for part in line:gmatch("([^:]+)") do
      table.insert(parts,part)
    end
    if #parts >= 3 and tonumber(parts[3]) == uid then
      return parts[1]
    end
  end
  return tostring(uid)
end

local function get_groupname_from_gid(gid)
  local group_content = bettola.read_file(context, "/etc/group")
  for line in group_content:gmatch("([^\n]+)") do
    local parts = {}
    for part in line:gmatch("([^:]+)") do
      table.insert(parts, part)
    end
    if #parts >= 3 and tonumber(parts[3]) == gid then
      return parts[1]
    end
  end
  return tostring(gid)
end

local function get_file_size(node)
  if node.type == 0 then -- FILE_NODE.
    return #node.content
  else
    return 0 -- Dirs don't have content size in this context.
  end
end

-- Cache for UID/GID to name mappings.
local uid_to_name_cache = {}
local gid_to_name_cache = {}

local function get_cached_username(uid)
  if not uid_to_name_cache[uid] then
    uid_to_name_cache[uid] = get_username_from_uid(uid)
  end
  return uid_to_name_cache[uid]
end

local function get_cached_groupname(gid)
  if not gid_to_name_cache[gid] then
    gid_to_name_cache[gid] = get_groupname_from_gid(gid)
  end
  return gid_to_name_cache[gid]
end

local function ls_long_format(dir)
  local output = {}
  for name, node in pairs(dir.children) do
    local line_type = (node.type == 1) and "d" or "-"
    local perms = format_permissions(node.permissions)
    local owner_name = get_cached_username(node.owner_id)
    local group_name = get_cached_groupname(node.group_id)
    local size  = get_file_size(node)
    table.insert(output, string.format("%s%s %s %s %5d %s", line_type, perms, owner_name,
      group_name, size, name))
  end
  table.sort(output)
  return table.concat(output, "\n")
end

local function ls_short_format(dir)
  local output = {}
  for name, node in pairs(dir.children) do
    local display_name = name
    if node.type == 1 then -- DIR_NODE
      display_name = display_name .. "/"
    elseif node.type == 2 then --EXEC_NODE
      display_name = display_name .. "*"
    end
    table.insert(output, display_name)
  end
  table.sort(output)
  return table.concat(output, "\t") -- Tab separated short format.
end

local current_dir = bettola.get_current_dir(context);

if arg[1] == "-l" then
  return ls_long_format(current_dir)
else
  return ls_short_format(current_dir)
end