-- Copyright 2007-2009 Mitchell mitchell<att>caladbolg.net. See LICENSE.

local textadept = _G.textadept
local locale = _G.locale

---
-- Module that handles Scintilla and Textadept notifications/events.
-- Most of Textadept's functionality comes through handlers. Scintilla
-- notifications, Textadept's own events, and user-defined events can all be
-- handled.
module('textadept.events', package.seeall)

-- Usage:
-- Each event can have multiple handlers, which are simply Lua functions that
-- are called in the sequence they are added as handler functions. Sometimes it
-- is useful to have a handler run under a specific condition(s). If this is the
-- case, place a conditional in the function that returns if it isn't met.
--
-- If a handler returns either true or false explicitly, all subsequent handlers
-- are not called. This is useful for something like a 'keypress' event where if
-- the key is handled, true should be returned so as to not propagate the event.
--
-- Events need not be declared. A handler can simply be added for an event name,
-- and 'handle'd when necessary. As an example, you can create a handler for a
-- custom 'my_event' and call "textadept.events.handle('my_event')" to envoke
-- it.
--
-- For reference, events will be shown in 'event(arguments)' format, but in
-- reality, the event is handled as 'handle(event, arguments)'.
--
-- Scintilla notifications:
--   char_added(ch)
--     ch: the (integer) character added.
--   save_point_reached()
--   save_point_left()
--   double_click(position, line)
--     position: the position of the beginning of the line clicked.
--     line: the line clicked.
--   update_ui()
--   margin_click(margin, modifiers, position)
--     margin: the margin number.
--     modifiers: mouse modifiers.
--     position: the position of the beginning of the line at the point clicked.
--   user_list_selection(wParam, text)
--     wParam: the user list ID.
--     text: the text of the selected item.
--   uri_dropped(text)
--     text: the URI dropped.
--   call_tip_click(position)
--     position: 1 or 2 if the up or down arrow was clicked; 0 otherwise.
--   auto_c_selection(lParam, text)
--     lParam: the start position of the word being completed.
--     text: the text of the selected item.
--
-- Textadept events:
--   buffer_new()
--   buffer_deleted()
--   buffer_before_switch()
--   buffer_after_switch()
--   view_new()
--   view_before_switch()
--   view_after_switch()
--   quit()
--     Note: when adding a quit handler, it must be inserted at index 1 because
--     the default quit handler returns true, which ignores all subsequent
--     handlers.
--   keypress(code, shift, control, alt)
--     code: the key code.
--     shift: flag indicating whether or not shift is pressed.
--     control: flag indicating whether or not control is pressed.
--     alt: flag indicating whether or not alt is pressed.
--   menu_clicked(menu_id)
--     menu_id: the numeric ID of the menu item.
--   pm_contents_request(full_path, expanding)
--     full_path: a numerically indexed table of treeview item parents. The
--       first index contains the text of pm_entry. Subsequent indexes contain
--       the ID's of parents of the child requested for expanding (if any).
--     expanding: indicates if the contents of a parent are being requested.
--   pm_item_selected(selected_item, gdkevent)
--     selected_item: identical to 'full_path' for 'pm_contents_request' event.
--     gdkevent: the GDK event associated with the request. It must be passed to
--       pm.show_context_menu()
--   pm_context_menu_request(selected_item)
--     selected_item: identical to 'full_path' for 'pm_contents_request' event.
--   pm_menu_clicked(menu_id, selected_item)
--     menu_id: the numeric ID for the menu item.
--     selected_item: identical to 'full_path' for 'pm_contents_request' event.
--   pm_view_filled()
--   find(text, next)
--     text: the text to find.
--     next: flag indicating whether or not the search direction is forward.
--   replace(text)
--     text: the text to replace the current selection with. It can contain both
--     Lua capture items (%n where 1 <= n <= 9) for Lua pattern searches and %()
--     sequences for embedding Lua code for any search.
--   replace_all(find_text, repl_text)
--     find_text: the text to find.
--     repl_text: the text to replace found text with.
--   find_keypress(code)
--     code: the key code.
--   command_entry_completions_request()
--   command_entry_keypress(code)
--     code: the key code.

local events = textadept.events

---
-- Adds a handler function to an event.
-- @param event The string event name.
-- @param f The Lua function to add.
-- @param index Optional index to insert the handler into.
function add_handler(event, f, index)
  local plural = event..'s'
  if not events[plural] then events[plural] = {} end
  local handlers = events[plural]
  if index then
    table.insert(handlers, index, f)
  else
    handlers[#handlers + 1] = f
  end
end

---
-- Calls every handler function added to an event in sequence.
-- If true or false is returned by any handler, the iteration ceases. Normally
-- this function is called by the system when necessary, but it can be called
-- in scripts to handle user-defined events.
-- @param event The string event name.
-- @param ... Arguments to the handler.
function handle(event, ...)
  local plural = event..'s'
  local handlers = events[plural]
  if not handlers then return end
  for _, f in ipairs(handlers) do
    local result = f(unpack{...})
    if result == true or result == false then return result end
  end
end

--- Map of Scintilla notifications to their handlers.
local c = textadept.constants
local scnnotifications = {
  [c.SCN_CHARADDED] = { 'char_added', 'ch' },
  [c.SCN_SAVEPOINTREACHED] = { 'save_point_reached' },
  [c.SCN_SAVEPOINTLEFT] = { 'save_point_left' },
  [c.SCN_DOUBLECLICK] = { 'double_click', 'position', 'line' },
  [c.SCN_UPDATEUI] = { 'update_ui' },
  [c.SCN_MARGINCLICK] = { 'margin_click', 'margin', 'modifiers', 'position' },
  [c.SCN_USERLISTSELECTION] = { 'user_list_selection', 'wParam', 'text' },
  [c.SCN_URIDROPPED] = { 'uri_dropped', 'text' },
  [c.SCN_CALLTIPCLICK] = { 'call_tip_click', 'position' },
  [c.SCN_AUTOCSELECTION] = { 'auto_c_selection', 'lParam', 'text' }
}

---
-- Handles Scintilla notifications.
-- @param n The Scintilla notification structure as a Lua table.
function notification(n)
  local f = scnnotifications[n.code]
  if f then
    local args = { unpack(f, 2) }
    for k, v in ipairs(args) do args[k] = n[v] end
    return handle(f[1], unpack(args))
  end
end

-- Default handlers to follow.

add_handler('view_new',
  function() -- sets default properties for a Scintilla window
    local buffer = buffer
    local c = textadept.constants

    -- properties
    buffer.property['textadept.home'] = _HOME
    buffer.property['lexer.lua.home'] = _LEXERPATH
    buffer.property['lexer.lua.script'] = _HOME..'/lexers/lexer.lua'
    if _THEME and #_THEME > 0 then
      local tfile = _THEME..'/lexer.lua'
      if not _THEME:find('[/\\]') then tfile = _HOME..'/themes/'..tfile end
      buffer.property['lexer.lua.color.theme'] = tfile
    end

    -- lexer
    buffer.style_bits = 8
    buffer.lexer = c.SCLEX_LPEG
    buffer:set_lexer_language('container')

    -- delete Windows/Linux key commands for Mac
    if MAC then
      buffer:clear_cmd_key(string.byte('Z'), c.SCMOD_CTRL)
      buffer:clear_cmd_key(string.byte('Y'), c.SCMOD_CTRL)
      buffer:clear_cmd_key(string.byte('X'), c.SCMOD_CTRL)
      buffer:clear_cmd_key(string.byte('C'), c.SCMOD_CTRL)
      buffer:clear_cmd_key(string.byte('V'), c.SCMOD_CTRL)
      buffer:clear_cmd_key(string.byte('A'), c.SCMOD_CTRL)
    end

    if _THEME and #_THEME > 0 then
      local vfile = _THEME..'/view.lua'
      if not _THEME:find('[/\\]') then vfile = _HOME..'/themes/'..vfile end
      local ret, errmsg = pcall(dofile, vfile)
      if ret then return end
      io.stderr:write(errmsg)
    end

    -- Default Theme (Light).

    -- caret
    buffer.caret_fore = 3355443 -- 0x33 | 0x33 << 8 | 0x33 << 16
    buffer.caret_line_visible = true
    buffer.caret_line_back = 14540253 -- 0xDD | 0xDD << 8 | 0xDD << 16
    buffer:set_x_caret_policy(1, 20) -- CARET_SLOP
    buffer:set_y_caret_policy(13, 1) -- CARET_SLOP | CARET_STRICT | CARET_EVEN

    -- selection
    buffer:set_sel_fore(1, 3355443) -- 0x33 | 0x33 << 8 | 0x33 << 16
    buffer:set_sel_back(1, 10066329) -- 0x99 | 0x99 << 8 | 0x99 << 16

    buffer.margin_width_n[0] = -- line number margin
      4 + 3 * buffer:text_width(c.STYLE_LINENUMBER, '9')

    buffer.margin_width_n[1] = 0 -- marker margin invisible

    -- fold margin
    buffer:set_fold_margin_colour(1, 13421772) -- 0xCC | 0xCC << 8 | 0xCC << 16
    buffer:set_fold_margin_hi_colour(1, 13421772) -- 0xCC | 0xCC << 8 | 0xCC << 16
    buffer.margin_type_n[2] = c.SC_MARGIN_SYMBOL
    buffer.margin_width_n[2] = 10
    buffer.margin_mask_n[2] = c.SC_MASK_FOLDERS
    buffer.margin_sensitive_n[2] = true

    -- fold margin markers
    buffer:marker_define(c.SC_MARKNUM_FOLDEROPEN, c.SC_MARK_ARROWDOWN)
    buffer:marker_set_fore(c.SC_MARKNUM_FOLDEROPEN, 0)
    buffer:marker_set_back(c.SC_MARKNUM_FOLDEROPEN, 0)
    buffer:marker_define(c.SC_MARKNUM_FOLDER, c.SC_MARK_ARROW)
    buffer:marker_set_fore(c.SC_MARKNUM_FOLDER, 0)
    buffer:marker_set_back(c.SC_MARKNUM_FOLDER, 0)
    buffer:marker_define(c.SC_MARKNUM_FOLDERSUB, c.SC_MARK_EMPTY)
    buffer:marker_define(c.SC_MARKNUM_FOLDERTAIL, c.SC_MARK_EMPTY)
    buffer:marker_define(c.SC_MARKNUM_FOLDEREND, c.SC_MARK_EMPTY)
    buffer:marker_define(c.SC_MARKNUM_FOLDEROPENMID, c.SC_MARK_EMPTY)
    buffer:marker_define(c.SC_MARKNUM_FOLDERMIDTAIL, c.SC_MARK_EMPTY)

    -- various
    buffer.call_tip_use_style = 0
    buffer:set_fold_flags(16)
    buffer.mod_event_mask = c.SC_MOD_CHANGEFOLD
  end)

add_handler('buffer_new',
  function() -- sets default properties for a Scintilla document
    local function run()
      local buffer = buffer

      -- lexer
      buffer.style_bits = 8
      buffer.lexer = textadept.constants.SCLEX_LPEG
      buffer:set_lexer_language('container')

      -- buffer
      buffer.code_page = textadept.constants.SC_CP_UTF8

      if _THEME and #_THEME > 0 then
        local bfile = _THEME..'/buffer.lua'
        if not _THEME:find('[/\\]') then bfile = _HOME..'/themes/'..bfile end
        local ret, errmsg = pcall(dofile, bfile)
        if ret then return end
        io.stderr:write(errmsg)
      end

      -- Default theme (Light).

      -- folding
      buffer.property['fold'] = '1'
      buffer.property['fold.by.indentation'] = '1'

      -- tabs and indentation
      buffer.tab_width = 2
      buffer.use_tabs = false
      buffer.indent = 2
      buffer.tab_indents = true
      buffer.back_space_un_indents = true
      buffer.indentation_guides = 1

      -- various
      buffer.auto_c_choose_single = true
    end
    -- normally when an error occurs, a new buffer is created with the error
    -- message, but if an error occurs here, this event would be called again
    -- and again, erroring each time resulting in an infinite loop; print error
    -- to stderr instead
    local ret, errmsg = pcall(run)
    if not ret then io.stderr:write(errmsg) end
  end)

---
-- [Local function] Sets the title of the Textadept window to the buffer's
-- filename.
-- @param buffer The currently focused buffer.
local function set_title(buffer)
  local buffer = buffer
  local filename = buffer.filename or buffer._type or locale.UNTITLED
  local dirty = buffer.dirty and '*' or '-'
  textadept.title =
    string.format('%s %s Textadept (%s)', filename:match('[^/\\]+$'), dirty,
                  filename)
end

add_handler('save_point_reached',
  function() -- changes Textadept title to show 'clean' buffer
    buffer.dirty = false
    set_title(buffer)
  end)

add_handler('save_point_left',
  function() -- changes Textadept title to show 'dirty' buffer
    buffer.dirty = true
    set_title(buffer)
  end)

add_handler('uri_dropped',
  function(utf8_uris)
    local lfs = require 'lfs'
    for utf8_uri in utf8_uris:gmatch('[^\r\n\f]+') do
      if utf8_uri:find('^file://') then
        utf8_uri = utf8_uri:match('^file://([^\r\n\f]+)')
        utf8_uri = utf8_uri:gsub('%%(%x%x)',
          function(hex) return string.char(tonumber(hex, 16)) end)
        if WIN32 then utf8_uri = utf8_uri:sub(2, -1) end -- ignore leading '/'
        local uri = textadept.iconv(utf8_uri, _CHARSET, 'UTF-8')
        if lfs.attributes(uri).mode ~= 'directory' then
          textadept.io.open(utf8_uri)
        end
      end
    end
  end)

local EOLs = {
  locale.STATUS_CRLF,
  locale.STATUS_CR,
  locale.STATUS_LF
}
add_handler('update_ui',
  function() -- sets docstatusbar text
    local buffer = buffer
    local pos = buffer.current_pos
    local line, max = buffer:line_from_position(pos) + 1, buffer.line_count
    local col = buffer.column[pos] + 1
    local lexer = buffer:get_lexer_language()
    local eol = EOLs[buffer.eol_mode + 1]
    local tabs = (buffer.use_tabs and locale.STATUS_TABS or
      locale.STATUS_SPACES)..buffer.indent
    local enc = buffer.encoding or ''
    textadept.docstatusbar_text =
      locale.DOCSTATUSBAR_TEXT:format(line, max, col, lexer, eol, tabs, enc)
  end)

add_handler('margin_click',
  function(margin, modifiers, position) -- toggles folding
    local buffer = buffer
    local line = buffer:line_from_position(position)
    buffer:toggle_fold(line)
  end)

add_handler('buffer_new',
  function() -- set additional buffer functions
    local buffer = buffer
    buffer.reload = textadept.io.reload
    buffer.set_encoding = textadept.io.set_encoding
    buffer.save = textadept.io.save
    buffer.save_as = textadept.io.save_as
    buffer.close = textadept.io.close
    buffer.encoding = 'UTF-8'
    set_title(buffer)
  end)

add_handler('buffer_before_switch',
  function() -- save buffer properties
    local buffer = buffer
    -- Save view state.
    buffer._anchor = buffer.anchor
    buffer._current_pos = buffer.current_pos
    buffer._first_visible_line = buffer.first_visible_line
    -- Save fold state.
    buffer._folds = {}
    local folds = buffer._folds
    local level, expanded = buffer.fold_level, buffer.fold_expanded
    local header_flag = textadept.constants.SC_FOLDLEVELHEADERFLAG
    local test = 2 * header_flag
    for i = 0, buffer.line_count do
      if level[i] % test >= header_flag and not expanded[i] then
        folds[#folds + 1] = i
      end
    end
  end)

add_handler('buffer_after_switch',
  function() -- restore buffer properties
    local buffer = buffer
    if not buffer._folds then return end
    -- Restore fold state.
    for _, i in ipairs(buffer._folds) do buffer:toggle_fold(i) end
    -- Restore view state.
    buffer:set_sel(buffer._anchor, buffer._current_pos)
    buffer:line_scroll(0,
      buffer:visible_from_doc_line(buffer._first_visible_line) -
        buffer.first_visible_line)
  end)

add_handler('buffer_after_switch',
  function() -- updates titlebar and statusbar
    set_title(buffer)
    handle('update_ui')
  end)

add_handler('view_after_switch',
  function() -- updates titlebar and statusbar
    set_title(buffer)
    handle('update_ui')
  end)

add_handler('quit',
  function() -- prompts for confirmation if any buffers are dirty
    local any = false
    local list = {}
    for _, buffer in ipairs(textadept.buffers) do
      if buffer.dirty then
        list[#list + 1] = buffer.filename or buffer._type or locale.UNTITLED
        any = true
      end
    end
    if any and
       textadept.dialog('yesno-msgbox',
                        '--title', locale.EVENTS_QUIT_TITLE,
                        '--text', locale.EVENTS_QUIT_TEXT,
                        '--informative-text',
                          string.format(locale.EVENTS_QUIT_MSG,
                                        table.concat(list, '\n')),
                        '--no-newline') ~= '2' then
      return false
    end
    return true
  end)

if MAC then
  add_handler('appleevent_odoc',
    function(uri) return handle('uri_dropped', 'file://'..uri) end)
end

add_handler('error',
  function(...) textadept._print(locale.ERROR_BUFFER, ...) end)