local M = {}

--- Apply mappings to a scratch buffer and return buffer local mappings
--- @param fn function(bufnr) on_attach or default_on_attach
--- @return table as per vim.api.nvim_buf_get_keymap
local function generate_keymap(fn)
  -- create an unlisted scratch buffer
  local scratch_bufnr = vim.api.nvim_create_buf(false, true)

  -- apply mappings
  fn(scratch_bufnr)

  -- retrieve all
  local keymap = vim.api.nvim_buf_get_keymap(scratch_bufnr, "")

  -- delete the scratch buffer
  vim.api.nvim_buf_delete(scratch_bufnr, { force = true })

  return keymap
end

-- stylua: ignore start
function M.default_on_attach(bufnr)
  local api = require('nvim-tree.api')

  local function opts(desc)
    return { desc = 'nvim-tree: ' .. desc, buffer = bufnr, noremap = true, silent = true, nowait = true }
  end

  -- BEGIN_DEFAULT_ON_ATTACH
  vim.keymap.set('n', '<C-]>', api.tree.change_root_to_node,          opts('CD'))
  vim.keymap.set('n', '<C-e>', api.node.open.replace_tree_buffer,     opts('Open: In Place'))
  vim.keymap.set('n', '<C-k>', api.node.show_info_popup,              opts('Info'))
  vim.keymap.set('n', '<C-r>', api.fs.rename_sub,                     opts('Rename: Omit Filename'))
  vim.keymap.set('n', '<C-t>', api.node.open.tab,                     opts('Open: New Tab'))
  vim.keymap.set('n', '<C-v>', api.node.open.vertical,                opts('Open: Vertical Split'))
  vim.keymap.set('n', '<C-x>', api.node.open.horizontal,              opts('Open: Horizontal Split'))
  vim.keymap.set('n', '<BS>',  api.node.navigate.parent_close,        opts('Close Directory'))
  vim.keymap.set('n', '<CR>',  api.node.open.edit,                    opts('Open'))
  vim.keymap.set('n', '<Tab>', api.node.open.preview,                 opts('Open Preview'))
  vim.keymap.set('n', '>',     api.node.navigate.sibling.next,        opts('Next Sibling'))
  vim.keymap.set('n', '<',     api.node.navigate.sibling.prev,        opts('Previous Sibling'))
  vim.keymap.set('n', '.',     api.node.run.cmd,                      opts('Run Command'))
  vim.keymap.set('n', '-',     api.tree.change_root_to_parent,        opts('Up'))
  vim.keymap.set('n', 'a',     api.fs.create,                         opts('Create'))
  vim.keymap.set('n', 'bd',    api.marks.bulk.delete,                 opts('Delete Bookmarked'))
  vim.keymap.set('n', 'bmv',   api.marks.bulk.move,                   opts('Move Bookmarked'))
  vim.keymap.set('n', 'B',     api.tree.toggle_no_buffer_filter,      opts('Toggle Filter: No Buffer'))
  vim.keymap.set('n', 'c',     api.fs.copy.node,                      opts('Copy'))
  vim.keymap.set('n', 'C',     api.tree.toggle_git_clean_filter,      opts('Toggle Filter: Git Clean'))
  vim.keymap.set('n', '[c',    api.node.navigate.git.prev,            opts('Prev Git'))
  vim.keymap.set('n', ']c',    api.node.navigate.git.next,            opts('Next Git'))
  vim.keymap.set('n', 'd',     api.fs.remove,                         opts('Delete'))
  vim.keymap.set('n', 'D',     api.fs.trash,                          opts('Trash'))
  vim.keymap.set('n', 'E',     api.tree.expand_all,                   opts('Expand All'))
  vim.keymap.set('n', 'e',     api.fs.rename_basename,                opts('Rename: Basename'))
  vim.keymap.set('n', ']e',    api.node.navigate.diagnostics.next,    opts('Next Diagnostic'))
  vim.keymap.set('n', '[e',    api.node.navigate.diagnostics.prev,    opts('Prev Diagnostic'))
  vim.keymap.set('n', 'F',     api.live_filter.clear,                 opts('Clean Filter'))
  vim.keymap.set('n', 'f',     api.live_filter.start,                 opts('Filter'))
  vim.keymap.set('n', 'g?',    api.tree.toggle_help,                  opts('Help'))
  vim.keymap.set('n', 'gy',    api.fs.copy.absolute_path,             opts('Copy Absolute Path'))
  vim.keymap.set('n', 'H',     api.tree.toggle_hidden_filter,         opts('Toggle Filter: Dotfiles'))
  vim.keymap.set('n', 'I',     api.tree.toggle_gitignore_filter,      opts('Toggle Filter: Git Ignore'))
  vim.keymap.set('n', 'J',     api.node.navigate.sibling.last,        opts('Last Sibling'))
  vim.keymap.set('n', 'K',     api.node.navigate.sibling.first,       opts('First Sibling'))
  vim.keymap.set('n', 'm',     api.marks.toggle,                      opts('Toggle Bookmark'))
  vim.keymap.set('n', 'o',     api.node.open.edit,                    opts('Open'))
  vim.keymap.set('n', 'O',     api.node.open.no_window_picker,        opts('Open: No Window Picker'))
  vim.keymap.set('n', 'p',     api.fs.paste,                          opts('Paste'))
  vim.keymap.set('n', 'P',     api.node.navigate.parent,              opts('Parent Directory'))
  vim.keymap.set('n', 'q',     api.tree.close,                        opts('Close'))
  vim.keymap.set('n', 'r',     api.fs.rename,                         opts('Rename'))
  vim.keymap.set('n', 'R',     api.tree.reload,                       opts('Refresh'))
  vim.keymap.set('n', 's',     api.node.run.system,                   opts('Run System'))
  vim.keymap.set('n', 'S',     api.tree.search_node,                  opts('Search'))
  vim.keymap.set('n', 'U',     api.tree.toggle_custom_filter,         opts('Toggle Filter: Hidden'))
  vim.keymap.set('n', 'W',     api.tree.collapse_all,                 opts('Collapse'))
  vim.keymap.set('n', 'x',     api.fs.cut,                            opts('Cut'))
  vim.keymap.set('n', 'y',     api.fs.copy.filename,                  opts('Copy Name'))
  vim.keymap.set('n', 'Y',     api.fs.copy.relative_path,             opts('Copy Relative Path'))
  vim.keymap.set('n', '<2-LeftMouse>',  api.node.open.edit,           opts('Open'))
  vim.keymap.set('n', '<2-RightMouse>', api.tree.change_root_to_node, opts('CD'))
  -- END_DEFAULT_ON_ATTACH
end
-- stylua: ignore end

function M.get_keymap()
  return generate_keymap(M.on_attach)
end

function M.get_keymap_default()
  return generate_keymap(M.default_on_attach)
end

function M.setup(opts)
  if type(opts.on_attach) ~= "function" then
    M.on_attach = M.default_on_attach
  else
    M.on_attach = opts.on_attach
  end
end

return M