-- Actions functions that are useful for people creating their own mappings.

local a = vim.api

local log = require('telescope.log')
local path = require('telescope.path')
local state = require('telescope.state')

local actions = setmetatable({}, {
  __index = function(_, k)
    error("Actions does not have a value: " .. tostring(k))
  end
})

local action_mt = {
  __call = function(t, ...)
    local values = {}
    for _, v in ipairs(t) do
      local result = {v(...)}
      for _, res in ipairs(result) do
        table.insert(values, res)
      end
    end

    return unpack(values)
  end,

  __add = function(lhs, rhs)
    local new_actions = {}
    for _, v in ipairs(lhs) do
      table.insert(new_actions, v)
    end

    for _, v in ipairs(rhs) do
      table.insert(new_actions, v)
    end

    return setmetatable(new_actions, getmetatable(lhs))
  end
}

local transform_action = function(a)
  return setmetatable({a}, action_mt)
end

--- Get the current picker object for the prompt
function actions.get_current_picker(prompt_bufnr)
  return state.get_status(prompt_bufnr).picker
end

--- Move the current selection of a picker {change} rows.
--- Handles not overflowing / underflowing the list.
function actions.shift_current_selection(prompt_bufnr, change)
  actions.get_current_picker(prompt_bufnr):move_selection(change)
end

function actions.move_selection_next(prompt_bufnr)
  actions.shift_current_selection(prompt_bufnr, 1)
end

function actions.move_selection_previous(prompt_bufnr)
  actions.shift_current_selection(prompt_bufnr, -1)
end

function actions.add_selection(prompt_bufnr)
  local current_picker = actions.get_current_picker(prompt_bufnr)
  current_picker:add_selection(current_picker:get_selection_row())
end

--- Get the current entry
function actions.get_selected_entry(prompt_bufnr)
  return actions.get_current_picker(prompt_bufnr):get_selection()
end

function actions.preview_scrolling_up(prompt_bufnr)
  actions.get_current_picker(prompt_bufnr).previewer:scroll_fn(-30)
end

function actions.preview_scrolling_down(prompt_bufnr)
  actions.get_current_picker(prompt_bufnr).previewer:scroll_fn(30)
end

-- TODO: It seems sometimes we get bad styling.
local function goto_file_selection(prompt_bufnr, command)
  local entry = actions.get_selected_entry(prompt_bufnr)

  if not entry then
    print("[telescope] Nothing currently selected")
    return
  else
    local filename, row, col
    if entry.filename then
      filename = entry.path or entry.filename

      -- TODO: Check for off-by-one
      row = entry.row or entry.lnum
      col = entry.col
    else
      -- TODO: Might want to remove this and force people
      -- to put stuff into `filename`
      local value = entry.value
      if not value then
        print("Could not do anything with blank line...")
        return
      end

      if type(value) == "table" then
        value = entry.display
      end

      local sections = vim.split(value, ":")

      filename = sections[1]
      row = tonumber(sections[2])
      col = tonumber(sections[3])
    end

    local preview_win = state.get_status(prompt_bufnr).preview_win
    if preview_win then
      a.nvim_win_set_config(preview_win, {style = ''})
    end

    local entry_bufnr = entry.bufnr

    actions.close(prompt_bufnr)

    filename = path.normalize(filename, vim.fn.getcwd())

    if entry_bufnr then
      vim.cmd(string.format(":%s #%d", command, entry_bufnr))
    else
      local bufnr = vim.api.nvim_get_current_buf()
      if filename ~= vim.api.nvim_buf_get_name(bufnr) then
        vim.cmd(string.format(":%s %s", command, filename))
        bufnr = vim.api.nvim_get_current_buf()
        a.nvim_buf_set_option(bufnr, "buflisted", true)
      end

      if row and col then
        local ok, err_msg = pcall(a.nvim_win_set_cursor, 0, {row, col})
        if not ok then
          log.debug("Failed to move to cursor:", err_msg, row, col)
        end
      end
    end
  end
end

function actions.center(_)
  vim.cmd(':normal! zz')
end

function actions.goto_file_selection_edit(prompt_bufnr)
  goto_file_selection(prompt_bufnr, "edit")
end

function actions.goto_file_selection_split(prompt_bufnr)
  goto_file_selection(prompt_bufnr, "new")
end

function actions.goto_file_selection_vsplit(prompt_bufnr)
  goto_file_selection(prompt_bufnr, "vnew")
end

function actions.goto_file_selection_tabedit(prompt_bufnr)
  goto_file_selection(prompt_bufnr, "tabedit")
end

function actions.close_pum(_)
  if 0 ~= vim.fn.pumvisible() then
    vim.api.nvim_feedkeys(vim.api.nvim_replace_termcodes("<c-y>", true, true, true), 'n', true)
  end
end

function actions.close(prompt_bufnr)
  local picker = actions.get_current_picker(prompt_bufnr)
  local prompt_win = state.get_status(prompt_bufnr).prompt_win
  local original_win_id = picker.original_win_id

  if picker.previewer then
    picker.previewer:teardown()
  end

  actions.close_pum(prompt_bufnr)
  vim.cmd [[stopinsert]]

  vim.api.nvim_win_close(prompt_win, true)

  pcall(vim.cmd, string.format([[silent bdelete! %s]], prompt_bufnr))
  pcall(a.nvim_set_current_win, original_win_id)
end

actions.set_command_line = function(prompt_bufnr)
  local entry = actions.get_selected_entry(prompt_bufnr)

  actions.close(prompt_bufnr)

  vim.cmd(entry.value)
end

actions.run_builtin = function(prompt_bufnr)
  local entry = actions.get_selected_entry(prompt_bufnr)

  actions.close(prompt_bufnr)
  vim.cmd [[startinsert]]

  require('telescope.builtin')[entry.text]()
end

-- TODO: Think about how to do this.
actions.insert_value = function(prompt_bufnr)
  local entry = actions.get_selected_entry(prompt_bufnr)

  vim.schedule(function()
    actions.close(prompt_bufnr)
  end)

  return entry.value
end

for k, v in pairs(actions) do
  actions[k] = transform_action(v)
end

actions._transform_action = transform_action

return actions