local api = vim.api
local config = require 'lib/config'

local M = {}

local function get_padding(depth)
  local str = ""

  while 0 < depth do
    str = str .. "  "
    depth = depth - 1
  end

  return str
end

local function default_icons(_, isdir, open)
  if isdir == true and config.SHOW_FOLDER_ICON then
    if open == true then return " " end
    return " "
  end

  return ""
end

local function create_matcher(arr)
  return function(name)
    for _, n in pairs(arr) do
      if name:match(n) then return true end
    end
    return false
  end
end

local is_special = create_matcher({
    'README',
    'readme',
    'Makefile',
    'Cargo%.toml',
  })

local is_pic = create_matcher({
    '%.jpe?g$',
    '%.png',
    '%.gif'
  })

local function is_executable(name)
  return api.nvim_call_function('executable', { name }) == 1
end

local function dev_icons(pathname, isdir, open)
  if isdir == true or is_special(pathname) == true or is_executable(pathname) == true or is_pic(pathname) == true then
    return default_icons(pathname, isdir, open)
  end

  local icon = api.nvim_call_function('WebDevIconsGetFileTypeSymbol', { pathname, isdir })
  if icon == "" then return "" end
  return icon  .. " "
end

local function get_icon_func_gen()
  if config.SHOW_FILE_ICON then
    return dev_icons
  else
    return default_icons
  end
end

local get_icon = get_icon_func_gen()

function M.format_tree(tree)
  local dirs = {}

  for i, node in pairs(tree) do
    local padding = get_padding(node.depth)
    local git = node.git
    local icon = ""
    local name = node.name
    if node.link == true then
      name = name .. ' ➛ ' .. node.linkto
    elseif node.icon == true then
      icon = get_icon(node.path .. node.name, node.dir, node.open)
    end
    dirs[i] = padding ..  icon .. git .. name
  end

  return dirs
end

local HIGHLIGHT_ICON_GROUPS = {
  ['^LICENSE$'] = 'LicenseIcon';
  ['^%.?vimrc$'] = 'VimIcon';
  ['%.vim$'] = 'VimIcon';
  ['%.c$'] = 'CIcon';
  ['%.cpp$'] = 'CIcon';
  ['%.cxx$'] = 'CIcon';
  ['%.h$'] = 'CIcon';
  ['%.hpp$'] = 'CIcon';
  ['%.py$'] = 'PythonIcon';
  ['%.lua$'] = 'LuaIcon';
  ['%.rs$'] = 'RustIcon';
  ['%.[cz]?sh$'] = 'ShellIcon';
  ['%.md$'] = 'MarkdownIcon';
  ['%.json$'] = 'JsonIcon';
  ['%.toml$'] = 'TomlIcon';
  ['%.yml$'] = 'YamlIcon';
  ['%.gitignore$'] = 'GitignoreIcon';
  ['%.js$'] = 'JavascriptIcon';
  ['%.ts$'] = 'TypescriptIcon';
  ['%.[tj]sx$'] = 'ReactIcon';
  ['%.html?$'] = 'HtmlIcon';
}

local function highlight_line(buffer)
  local function highlight(group, line, from, to)
    api.nvim_buf_add_highlight(buffer, -1, group, line, from, to)
  end
  return function(line, node)
    local text_start = node.depth * 2
    local gitlen = string.len(node.git)
    if node.name == '..' then
      highlight('LuaTreeFolderName', line, 0, -1)

    elseif node.dir == true then
      if config.SHOW_FOLDER_ICON then
        text_start = text_start + 4
        highlight('LuaTreeFolderIcon', line, 0, text_start)
      end
      highlight('LuaTreeFolderName', line, text_start + gitlen, -1)

    elseif node.link == true then
      highlight('LuaTreeSymlink', line, 0, -1)

    elseif is_special(node.name) == true then
      highlight('LuaTreeSpecialFile', line, text_start + gitlen, -1)

    elseif is_executable(node.path .. node.name) then
      highlight('LuaTreeExecFile', line, text_start + gitlen, -1)

    elseif is_pic(node.path .. node.name) then
      highlight('LuaTreeImageFile', line, text_start + gitlen, -1)

    elseif config.SHOW_FILE_ICON then
      for k, v in pairs(HIGHLIGHT_ICON_GROUPS) do
        if node.name:match(k) ~= nil then
          text_start = text_start + 4
          highlight('LuaTree' .. v, line, 0, text_start)
          break
        end
      end
    end

    if node.git == '' then return end

    if node.git == '✗ ' then
      highlight('LuaTreeGitDirty', line, text_start, text_start + gitlen)
    elseif node.git == '✓ ' then
      highlight('LuaTreeGitStaged', line, text_start, text_start + gitlen)
    elseif node.git == '✓★ ' then
      highlight('LuaTreeGitStaged', line, text_start, text_start + 3)
      highlight('LuaTreeGitNew', line, text_start + 3, text_start + gitlen)
    elseif node.git == '✓✗ ' then
      highlight('LuaTreeGitStaged', line, text_start, text_start + 3)
      highlight('LuaTreeGitDirty', line, text_start + 3, text_start + gitlen)
    elseif node.git == '═ ' then
      highlight('LuaTreeGitMerge', line, text_start, text_start + gitlen)
    elseif node.git == '➜ ' then
      highlight('LuaTreeGitRenamed', line, text_start, text_start + gitlen)
    elseif node.git == '★ ' then
      highlight('LuaTreeGitNew', line, text_start, text_start + gitlen)
    end
  end
end

function M.highlight_buffer(buffer, tree)
  local highlight = highlight_line(buffer)
  for i, node in pairs(tree) do
    highlight(i - 1, node)
  end
end

return M