local log = require "nvim-tree.log"
local utils = require "nvim-tree.utils"
local view = require "nvim-tree.view"
local _padding = require "nvim-tree.renderer.components.padding"
local _help = require "nvim-tree.renderer.help"
local _icons = require "nvim-tree.renderer.icon-config"
local git = require "nvim-tree.renderer.components.git"
local core = require "nvim-tree.core"

local api = vim.api

local M = {}

local lines = {}
local hl = {}
local index = 0
local namespace_id = api.nvim_create_namespace "NvimTreeHighlights"

local icon_state = _icons.get_config()
local web_devicons = icon_state.has_devicons and require "nvim-web-devicons" or nil

local should_hl_opened_files = (vim.g.nvim_tree_highlight_opened_files or 0) ~= 0

local icon_padding = vim.g.nvim_tree_icon_padding or " "

-- ## SYMLINK

local get_symlink_icon = function()
  return #icon_state.icons.symlink > 0 and icon_state.icons.symlink .. icon_padding or ""
end

local function build_symlink(node, padding, offset, git_hl)
  local icon = get_symlink_icon()
  local link_hl = git_hl or "NvimTreeSymlink"
  local arrow = vim.g.nvim_tree_symlink_arrow or " ➛ "
  table.insert(hl, { link_hl, index, offset, -1 })
  table.insert(lines, padding .. icon .. node.name .. arrow .. node.link_to)
  index = index + 1
end

-- ## FILES

local get_file_icon = function()
  return ""
end

local get_file_icon_default = function(_, _, line, depth)
  local hl_group = "NvimTreeFileIcon"
  local icon = icon_state.icons.default
  if #icon > 0 then
    table.insert(hl, { hl_group, line, depth, depth + #icon + 1 })
  end
  return #icon > 0 and icon .. icon_padding or ""
end

local get_file_icon_webdev = function(fname, extension, line, depth)
  local icon, hl_group = web_devicons.get_icon(fname, extension)
  if not M.config.icons.webdev_colors then
    hl_group = "NvimTreeFileIcon"
  end
  if icon and hl_group ~= "DevIconDefault" then
    if hl_group then
      table.insert(hl, { hl_group, line, depth, depth + #icon + 1 })
    end
    return icon .. icon_padding
  elseif string.match(extension, "%.(.*)") then
    -- If there are more extensions to the file, try to grab the icon for them recursively
    return get_file_icon(fname, string.match(extension, "%.(.*)"), line, depth)
  else
    return get_file_icon_default(fname, extension, line, depth)
  end
end

if icon_state.show_file_icon then
  if web_devicons then
    get_file_icon = get_file_icon_webdev
  else
    get_file_icon = get_file_icon_default
  end
end

local get_special_icon = function()
  return ""
end
if icon_state.show_file_icon then
  get_special_icon = function()
    return #icon_state.icons.default > 0 and icon_state.icons.default .. icon_padding or ""
  end
end

local picture = {
  jpg = true,
  jpeg = true,
  png = true,
  gif = true,
}

local function get_special_files_map()
  return vim.g.nvim_tree_special_files
    or {
      ["Cargo.toml"] = true,
      Makefile = true,
      ["README.md"] = true,
      ["readme.md"] = true,
    }
end

local function highlight_opened_files(node, offset, icon, git_icons)
  local from = offset
  local to = offset

  if vim.g.nvim_tree_highlight_opened_files == 1 then -- highlight icon only
    to = from + #icon
  elseif vim.g.nvim_tree_highlight_opened_files == 2 then -- highlight name only
    from = offset + #icon + #git_icons
    to = from + #node.name
  elseif vim.g.nvim_tree_highlight_opened_files == 3 then -- highlight whole line
    to = -1
  end

  table.insert(hl, { "NvimTreeOpenedFile", index, from, to })
end

local function build_file(node, padding, offset, git_hl, special)
  local icon
  local git_icons
  if special[node.absolute_path] or special[node.name] then
    icon = get_special_icon()
    git_icons = git.get_icons(node, index, offset, 0, hl)
    table.insert(hl, { "NvimTreeSpecialFile", index, offset + #git_icons, -1 })
  else
    icon = get_file_icon(node.name, node.extension, index, offset)
    git_icons = git.get_icons(node, index, offset, #icon, hl)
  end
  table.insert(lines, padding .. icon .. git_icons .. node.name)

  if node.executable then
    table.insert(hl, { "NvimTreeExecFile", index, offset + #icon + #git_icons, -1 })
  elseif picture[node.extension] then
    table.insert(hl, { "NvimTreeImageFile", index, offset + #icon + #git_icons, -1 })
  end

  local should_highlight_opened_files = should_hl_opened_files and vim.fn.bufloaded(node.absolute_path) > 0
  if should_highlight_opened_files then
    highlight_opened_files(node, offset, icon, git_icons)
  end

  if git_hl then
    table.insert(hl, { git_hl, index, offset + #icon + #git_icons, -1 })
  end
  index = index + 1
end

-- ## FOLDERS

local function get_trailing_length()
  return vim.g.nvim_tree_add_trailing and 1 or 0
end

local get_folder_icon = function()
  return ""
end

local set_folder_hl = function(line, depth, git_icon_len, _, hl_group, _)
  table.insert(hl, { hl_group, line, depth + git_icon_len, -1 })
end

if icon_state.show_folder_icon then
  get_folder_icon = function(open, is_symlink, has_children)
    local n
    if is_symlink and open then
      n = icon_state.icons.folder_icons.symlink_open
    elseif is_symlink then
      n = icon_state.icons.folder_icons.symlink
    elseif open then
      if has_children then
        n = icon_state.icons.folder_icons.open
      else
        n = icon_state.icons.folder_icons.empty_open
      end
    else
      if has_children then
        n = icon_state.icons.folder_icons.default
      else
        n = icon_state.icons.folder_icons.empty
      end
    end
    return n .. icon_padding
  end
  set_folder_hl = function(line, depth, icon_len, name_len, hl_icongroup, hl_fnamegroup)
    local hl_icon = should_hl_opened_files and hl_icongroup or "NvimTreeFolderIcon"
    table.insert(hl, { hl_icon, line, depth, depth + icon_len })
    table.insert(hl, { hl_fnamegroup, line, depth + icon_len, depth + icon_len + name_len + get_trailing_length() })
  end
end

local function build_folder(node, padding, offset, depth, git_hl, special, markers)
  local has_children = #node.nodes ~= 0 or node.has_children
  local icon = get_folder_icon(node.open, node.link_to ~= nil, has_children)
  local git_icon = git.get_icons(node, index, offset, #icon, hl) or ""
  -- INFO: this is mandatory in order to keep gui attributes (bold/italics)
  local folder_hl = "NvimTreeFolderName"
  local name = node.name
  local next = node.group_next
  while next do
    name = name .. "/" .. next.name
    next = next.group_next
  end
  if not has_children then
    folder_hl = "NvimTreeEmptyFolderName"
  end
  if node.open then
    folder_hl = "NvimTreeOpenedFolderName"
  end
  if special[node.absolute_path] then
    folder_hl = "NvimTreeSpecialFolderName"
  end
  set_folder_hl(index, offset, #icon + #git_icon, #name, "NvimTreeFolderIcon", folder_hl)
  if git_hl then
    set_folder_hl(index, offset, #icon + #git_icon, #name, git_hl, git_hl)
  end
  index = index + 1
  if node.open then
    table.insert(lines, padding .. icon .. git_icon .. name .. (vim.g.nvim_tree_add_trailing == 1 and "/" or ""))
    M._update_draw_data(node, depth + 2, markers)
  else
    table.insert(lines, padding .. icon .. git_icon .. name .. (vim.g.nvim_tree_add_trailing == 1 and "/" or ""))
  end
end

function M._update_draw_data(tree, depth, markers)
  local special = get_special_files_map()

  for idx, node in ipairs(tree.nodes) do
    local padding = _padding.get_padding(depth, idx, tree, node, markers)
    local offset = string.len(padding)
    if depth > 0 then
      table.insert(hl, { "NvimTreeIndentMarker", index, 0, offset })
    end

    local git_hl = git.get_highlight(node)

    if node.nodes then
      build_folder(node, padding, offset, depth, git_hl, special, markers)
    elseif node.link_to then
      build_symlink(node, padding, offset, git_hl)
    else
      build_file(node, padding, offset, git_hl, special)
    end
  end
end

local function compute_header()
  if view.is_root_folder_visible(core.get_cwd()) then
    local root_folder_modifier = vim.g.nvim_tree_root_folder_modifier or ":~"
    local root_name = utils.path_join {
      utils.path_remove_trailing(vim.fn.fnamemodify(core.get_cwd(), root_folder_modifier)),
      "..",
    }
    table.insert(lines, root_name)
    table.insert(hl, { "NvimTreeRootFolder", index, 0, string.len(root_name) })
    index = 1
  end
end

local function _draw(bufnr)
  api.nvim_buf_set_option(bufnr, "modifiable", true)
  api.nvim_buf_set_lines(bufnr, 0, -1, false, lines)
  M.render_hl(bufnr)
  api.nvim_buf_set_option(bufnr, "modifiable", false)
end

function M.draw()
  local bufnr = view.get_bufnr()
  if not core.get_explorer() or not bufnr or not api.nvim_buf_is_loaded(bufnr) then
    return
  end

  local ps = log.profile_start "draw"

  local cursor
  if view.is_visible() then
    cursor = api.nvim_win_get_cursor(view.get_winnr())
  end
  index = 0
  lines = {}
  hl = {}

  icon_state = _icons.get_config()
  local show_arrows = not M.config.indent_markers.enable
    and icon_state.show_folder_icon
    and icon_state.show_folder_arrows
  _padding.reload_padding_function()
  git.reload()
  compute_header()
  M._update_draw_data(core.get_explorer(), show_arrows and 2 or 0, {})

  if view.is_help_ui() then
    lines, hl = _help.compute_lines()
  end

  _draw(bufnr)

  if cursor and #lines >= cursor[1] then
    api.nvim_win_set_cursor(view.get_winnr(), cursor)
  end

  log.profile_end(ps, "draw")
end

function M.render_hl(bufnr)
  if not bufnr or not api.nvim_buf_is_loaded(bufnr) then
    return
  end
  api.nvim_buf_clear_namespace(bufnr, namespace_id, 0, -1)
  for _, data in ipairs(hl) do
    api.nvim_buf_add_highlight(bufnr, namespace_id, data[1], data[2], data[3], data[4])
  end
end

function M.setup(opts)
  M.config = {
    indent_markers = opts.renderer.indent_markers,
    icons = opts.renderer.icons,
  }

  _padding.setup(opts)
end

return M