local popup = require'plenary.popup'
local utils = require'presser.utils'

local api = vim.api

local presser = {}  -- list of functions to be exported
local g = vim.g

g.presser_buf_ctx = {} -- setup a new global context manager for windows/buffers

-- :@Dev: close all Presser windows that may be open for all contexts
presser.close = function ()
  for _type, ctx in pairs( g.presser_buf_ctx ) do
    for _, win_id in pairs( ctx ) do
      api.nvim_win_close( win_id, true ) -- buffer contents are irrelevant in this context to save
    end
  end

  g.presser_buf_ctx = {} -- clear the global context manager
end

-- @Description: Construct a new instance of a window and buffer using the 'plenary.popup' module.
-- @Params:
--    + `_type` ~ string denoting which context manager is owner of the window.
--    + `placeholder` ~ string allowing for placeholder text to be placed within the buffer when constructed.
--    + `opts` ~ a table of additional options to be provided when constructing the window.
-- @Returns: nil. Constructs a new window and stores the window's ID in a global table.
--
-- @Dev: This function is to be as generic for creating a window whilst allowing for as much customisation over the
-- window/buffer which are to be constructed. Users are to access this function so is not part of the module export.
-- However, it's used by all internal built-ins which are meant to be used by users. Consider a class constructor in
-- C++, this function is akin to that behaviour and is responsible for constructing the window/buffer and ensuring it
-- can be tracked by Vim itself.
local new = function ( _type, placeholder, opts )
  -- create new manager for handling windows in the 
  local manager = g.presser_buf_ctx
  -- create specific context manager if it doesn't exist
  if not manager[_type] then
    manager[_type] = {}
    g.presser_buf_ctx = manager
  end

  local opts = opts or {}
  local placeholder = placeholder or ""
  
  local buf_opts = {
    minwidth = 80, -- getwin_w() / 2 - ((getwin_w() % 2) / 2),
    borderchars = { "─", "│", "─", "│", "╭", "╮", "╯", "╰" },
  }

  if opts.window then
    for k,v in pairs( opts.window ) do
      buf_opts[k] = v
    end
  end

  local obj = popup.create( placeholder, buf_opts )
  table.insert( manager[_type], obj )
  g.presser_buf_ctx = manager

  -- :@Dev: handle for keybindings (TODO: any future stuff below here once window is made)
  local buf_id = function ()
    return api.nvim_win_get_buf(obj)
  end

  -- handle for key bindings
  if opts.keybinds then
    for mode, mode_map in pairs( opts.keybinds ) do
      mode = string.lower(mode)

      for key_bind, key_action in pairs(mode_map) do
        local key_bind = api.nvim_replace_termcodes(key_bind, true, false, true),
        api.nvim_buf_set_keymap(buf_id(), mode, key_bind, key_action,
          { noremap = true, silent = true }
        )
      end
    end
  end
end

-- @Description: Find and replace words within the current buffer.
-- @Params:
-- @Returns: nil.
--
-- @Dev: function is responsible to creating all required buffers to allow full user interaction.
--
-- @Future: implementation may allow for greater user customisation similar to what's found with
-- extensions such as Telescope. For now, it should provide a concrete UI for purpose of design.
function presser.find_replace()
  -- define the context which these windows will belong to in the context manager.
  local ctx = "find_replace"
  
  local keymap = {
    n = {
      ["<esc>"] = "<cmd>lua require'presser'.close()<CR>",
    },
  }

  -- options for the title buffer of the built-in
  local opts = {
    window = {
      line = 12,
      border = false,
      minwidth = 82,
      padding = { 0, 1, 1, 1 }
    },
    keybinds = keymap,
  }
  local tab_title = new( ctx, "Find & Replace", opts )

  -- options for the replace buffer
  local opts = {
    window = {
      line = 18,
      title = "Replace",
    },
    keybinds = keymap,
  }
  local replace = new( ctx, nil, opts )

  -- modify options for find buffer
  opts["window"]["line"] = 15
  opts["window"]["title"] = "Find"
  local find = new ( ctx, nil, opts )

  api.nvim_feedkeys('A', 'n', false)
end


return presser