local Luan = require "luan:Luan.luan"
local error = Luan.error
local ipairs = Luan.ipairs or error()
local stringify = Luan.stringify or error()
local String = require "luan:String.luan"
local sub_string = String.sub or error()
local replace = String.replace or error()
local starts_with = String.starts_with or error()
local to_number = String.to_number or error()
local Io = require "luan:Io.luan"
local print = Io.print or error()
local new_file = Io.schemes.file or error()
local Math = require "luan:Math.luan"
local min = Math.min or error()
local Swing = require "luan:swing/Swing.luan"
local new_frame = require("luan:swing/Frame.luan").new or error()
local new_label = require("luan:swing/Label.luan").new or error()
local new_text_area = require("luan:swing/Text_area.luan").new or error()
local new_scroll_pane = require("luan:swing/Scroll_pane.luan").new or error()
local new_text_area_line_numbers = require("luan:swing/Text_area_line_numbers.luan").new or error()
local new_menu_bar = require("luan:swing/Menu_bar.luan").new or error()
local Menu = require "luan:swing/Menu.luan"
local new_menu = Menu.new or error()
local separator = Menu.separator or error()
local new_menu_item = require("luan:swing/Menu_item.luan").new or error()
local new_check_box_menu_item = require("luan:swing/Check_box_menu_item.luan").new or error()
local int_to_color = require("luan:swing/Color.luan").int_to_color or error()
local Border = require "luan:swing/Border.luan"
local create_empty_border = Border.create_empty_border or error()
local create_line_border = Border.create_line_border or error()
local Layout = require "luan:swing/Layout.luan"
local new_flow_layout = Layout.new_flow_layout or error()
local new_box_layout = Layout.new_box_layout or error()
local Option_pane = require "luan:swing/Option_pane.luan"
local show_message_dialog = Option_pane.show_message_dialog or error()
local show_input_dialog = Option_pane.show_input_dialog or error()
local new_dialog = require("luan:swing/Dialog.luan").new or error()
local new_panel = require("luan:swing/Component.luan").new_panel or error()
local new_button = require("luan:swing/Button.luan").new or error()
local Logging = require "luan:logging/Logging.luan"
local logger = Logging.logger "editor"


local new_window

local function action_listener(fn)
	return function(_)
		fn()
	end
end

local function make_menu_bar(window)
	local document = window.text_area.document
	local revert = new_menu_item{
		text = "Revert"
		enabled = window.has_file
		action_listener = action_listener(window.revert)
	}
	local undo = new_menu_item{
		text = "Undo"
		accelerator = "meta Z"
		action_listener = action_listener(document.undo)
	}
	local redo = new_menu_item{
		text = "Redo"
		accelerator = "meta shift Z"
		action_listener = action_listener(document.redo)
	}
	local function update_undo_redo()
		undo.set_enabled(document.can_undo())
		redo.set_enabled(document.can_redo())
	end
	window.update_undo_redo = update_undo_redo  -- dont gc
	update_undo_redo()
	document.add_undo_listener(update_undo_redo)

	return new_menu_bar{
		menus = {
			new_menu{
				text = "File"
				menu_items = {
					new_menu_item{
						text = "New File"
						accelerator = "meta N"
						action_listener = function(_)
							new_window()
						end
					}
					new_menu_item{
						text = "Open..."
						accelerator = "meta O"
						action_listener = action_listener(window.open)
					}
					new_menu_item{
						text = "Save"
						accelerator = "meta S"
						action_listener = function(_)
							if window.save() then
								revert.set_enabled(true)
							end
						end
					}
					revert
				}
			}
			new_menu{
				text = "Edit"
				menu_items = {
					undo
					redo
					separator
					new_menu_item{
						text = "Cut"
						accelerator = "meta X"
						action_listener = action_listener(window.text_area.cut)
					}
					new_menu_item{
						text = "Copy"
						accelerator = "meta C"
						action_listener = action_listener(window.text_area.copy)
					}
					new_menu_item{
						text = "Paste"
						accelerator = "meta V"
						action_listener = action_listener(window.text_area.paste)
					}
					separator
					new_menu_item{
						text = "Indent"
						accelerator = "meta CLOSE_BRACKET"
						action_listener = action_listener(window.indent)
					}
					new_menu_item{
						text = "Unindent"
						accelerator = "meta OPEN_BRACKET"
						action_listener = action_listener(window.unindent)
					}
					separator
					new_menu_item{
						text = "Select All"
						accelerator = "meta A"
						action_listener = action_listener(window.text_area.select_all)
					}
					separator
					new_menu_item{
						text = "Find and Replace"
						accelerator = "meta F"
						action_listener = action_listener(window.show_find_dialog)
					}
				}
			}
			new_menu{
				text = "View"
				menu_items = {
					new_check_box_menu_item{
						text = "Word Wrap"
						state = window.text_area.line_wrap
						action_listener = function(event)
							window.text_area.line_wrap = event.source.state
						end
					}
					new_check_box_menu_item{
						text = "Show Whitespace"
						action_listener = function(event)
							window.text_area.show_whitespace(event.source.state)
						end
					}
					new_menu_item{
						text = "Show Cursor Column"
						action_listener = function(_)
							show_message_dialog( window.frame, "Cursor Column: "..window.cursor_column() )
						end
					}
					new_menu_item{
						text = "Goto Line"
						accelerator = "meta G"
						action_listener = function(_)
							local input = show_input_dialog( window.frame, "Goto line" )
							--logger.info("input "..input)
							local line = input and to_number(input)
							if line ~= nil then
								window.goto(line)
							end
						end
					}
				}
			}
		}
	}
end

local function make_find_dialog(window)
	local dialog = new_dialog{
		owner_frame = window.frame
		content_pane = new_panel{
			layout = function(this) return new_box_layout(this,"y_axis") end
			children = {
				new_panel{
					layout = new_flow_layout("left")
					--border = create_empty_border(8,8,8,8)
					border = create_line_border(int_to_color(0))
					children = {
						new_button{
							text = "Find Next"
						}
						new_button{
							text = "Find Previous"
						}
					}
				}
			}
		}
	}
	dialog.pack()
	local was_shown = false
	function window.show_find_dialog()
		if not was_shown then
			was_shown = true
			dialog.move_into_owner()
		end
		dialog.visible = true
	end
end

local n_windows = 0
local documents = {}

function new_window(file)
	local window = {}
	window.has_file = file~=nil and file.is_file()
	local text_area = new_text_area{
		rows = 10
		columns = 20
		wrap_style_word = true
		line_wrap = true
		tab_size = 4
		font = { family="Monospaced", size=13 }
		border = create_empty_border(0,4,0,4)
	}
	window.text_area = text_area
	local title = file and file.canonical().to_string() or "new"
	if file ~= nil then
		local document = documents[title]
		if document == nil then
			documents[title] = text_area.document
		else
			text_area.document = document
		end
		if file.is_file() then
			text_area.text = file.read_text()
			text_area.document.clear_unedited()
		end
	end
	text_area.set_selection(0)
	local frame = new_frame{
		content_pane = new_scroll_pane{
			view = text_area
			row_header_view = new_text_area_line_numbers{
				text_area = text_area
				foreground_color = int_to_color(0x888888)
				border = create_empty_border(0,8,0,8)
			}
		}
	}
	window.frame = frame
	frame.add_close_listener(function()
		n_windows = n_windows - 1
		if n_windows == 0 then
			Luan.exit()
		end
	end)
	local function set_title()
		local s = title
		if not text_area.document.is_unedited() then
			s = s.." *"
		end
		frame.title = s
	end
	set_title()
	window.set_title = set_title  -- dont gc
	text_area.document.add_undo_listener(set_title)
	function window.open()
		local file_chooser = frame.file_chooser_load()
		if file ~= nil then
			file_chooser.directory = file.parent()
		end
		file_chooser.visible = true
		local new_file = file_chooser.file
		if new_file ~= nil then
			new_window(new_file)
		end
	end
	function window.save()
		if file == nil then
			local file_chooser = frame.file_chooser_save()
			file_chooser.visible = true
			file = file_chooser.file
			if file == nil then
				return false
			end
			title = file.canonical().to_string()
			frame.title = title
			documents[title] = text_area.document
		end
		file.write_text(text_area.text)
		text_area.document.set_unedited()
		return true
	end
	function window.revert()
		local selection = text_area.get_selection()
		local text = file.read_text()
		text_area.text = text
		text_area.set_selection(min(selection,#text+1))
		text_area.document.set_unedited()
	end
	local function selection_lines()
		local start_seletion, end_selection = text_area.get_selection()
		local end_ = end_selection == start_seletion and end_selection or end_selection - 1
		local start_line = text_area.get_line_from_position(start_seletion)
		local end_line = text_area.get_line_from_position(end_)
		local start_pos = text_area.get_line_start_position(start_line)
		local end_pos = text_area.get_line_end_position(end_line)
		local text = text_area.text
		text = sub_string(text,start_pos,end_pos-2)
		return {
			text = text
			start_pos = start_pos
			length = #text
			lines = end_line - start_line + 1
			start_seletion = start_seletion
			end_selection = end_selection
		}
	end
	function window.indent()
		local r = selection_lines()
		local text = r.text
		local start_pos = r.start_pos
		text = "\t"..replace(text,"\n","\n\t")
		text_area.replace(start_pos,r.length,text)
		--logger.info(stringify{text_area.get_selection()})
		text_area.set_selection( r.start_seletion+1, r.end_selection+r.lines )
	end
	function window.unindent()
		local r = selection_lines()
		local text = r.text
		text = "\n"..text
		local start_seletion = r.start_seletion
		if starts_with(text,"\n\t") then
			start_seletion = start_seletion - 1
		end
		local len1 = #text
		text = replace(text,"\n\t","\n")
		local len2 = #text
		local end_selection = r.end_selection - (len1 - len2)
		text = sub_string(text,2)
		text_area.replace(r.start_pos,r.length,text)
		text_area.set_selection(start_seletion,end_selection)
	end
	function window.cursor_column()
		local cursor_pos = text_area.get_selection()
		local line = text_area.get_line_from_position(cursor_pos)
		local start_line_pos = text_area.get_line_start_position(line)
		return cursor_pos - start_line_pos + 1
	end
	function window.goto(line)
		local pos = text_area.get_line_start_position(line)
		text_area.set_selection(pos)
	end
	make_find_dialog(window)
	local menu_bar = make_menu_bar(window)
	frame.set_menu_bar(menu_bar)
	frame.pack()
	frame.visible = true
	text_area.request_focus_in_window()
	n_windows = n_windows + 1
end

Swing.run(function()
	local args = Luan.arg
	if #args == 0 then
		new_window()
	else
		for _, arg in ipairs(args) do
			local file = new_file(arg)
			new_window(file)
		end
	end
end)