-- Copyright 2007-2011 Mitchell mitchell<att>caladbolg.net. See LICENSE.

---
-- The lua module.
-- It provides utilities for editing Lua code.
-- User tags are loaded from _USERHOME/modules/lua/tags and user apis are loaded
-- from _USERHOME/modules/lua/api.
module('_m.lua', package.seeall)

-- Markdown:
-- ## Key Commands
--
-- + `Alt+L, M`: Open this module for editing.
-- + `Alt+L, G`: Goto file being 'require'd on the current line.
-- + `Shift+Return`: Try to autocomplete an `if`, `for`, etc. statement with
--   `end`.
-- + `.`: When to the right of a known symbol, show an autocompletion list of
--   fields and functions.
-- + `:`: When to the right of a known symbol, show an autocompletion list of
--   functions only.
-- + `Ctrl+I`: (Windows and Linux) Autocomplete symbol.
-- + `~`: (Mac OSX) Autocomplete symbol.
-- + `Ctrl+H`: Show documentation for the selected symbol or the symbol under
--   the caret.
--
-- ## Fields
--
-- * `sense`: The Lua [Adeptsense](_m.textadept.adeptsense.html).

local m_editing, m_run = _m.textadept.editing, _m.textadept.run
-- Comment string tables use lexer names.
m_editing.comment_string.lua = '--'
-- Compile and Run command tables use file extensions.
m_run.run_command.lua = 'lua %(filename)'
m_run.error_detail.lua = {
  pattern = '^lua: (.-):(%d+): (.+)$',
  filename = 1, line = 2, message = 3
}

---
-- Sets default buffer properties for Lua files.
function set_buffer_properties()

end

-- Adeptsense.

sense = _m.textadept.adeptsense.new('lua')
sense.syntax.class_definition = 'module%s*%(?%s*[\'"]([%w_%.]+)'
sense.syntax.symbol_chars = '[%w_%.:]'
sense.syntax.type_declarations = {}
sense.syntax.type_assignments = {
  ['^[\'"]'] = 'string', -- foo = 'bar' or foo = "bar"
  ['^([%w_%.]+)%s*$'] = '%1', -- foo = _m.textadept.adeptsense
  ['^(_m%.textadept%.adeptsense)%.new'] = '%1',
  ['require%s*%(?%s*(["\'])([%w_%.]+)%1%)?'] = '%2'
}
sense.api_files = { _HOME..'/modules/lua/api' }
sense:add_trigger('.')
sense:add_trigger(':', false, true)

-- script/update_doc generates a fake set of ctags used for autocompletion.
sense.ctags_kinds = {
  f = 'functions',
  F = 'fields',
  m = 'classes',
  t = 'fields',
}
sense:load_ctags(_HOME..'/modules/lua/tags', true)

-- Shows an autocompletion list for the symbol behind the caret.
-- If the symbol contains a ':', only display functions. Otherwise, display
-- both functions and fields.
function sense:complete(only_fields, only_functions)
  local line, pos = buffer:get_cur_line()
  local symbol = line:sub(1, pos):match(self.syntax.symbol_chars..'*$')
  return self.super.complete(self, false, symbol:find(':'))
end

-- Load user tags and apidoc.
if lfs.attributes(_USERHOME..'/modules/lua/tags') then
  sense:load_ctags(_USERHOME..'/modules/lua/tags')
end
if lfs.attributes(_USERHOME..'/modules/lua/api') then
  sense.api_files[#sense.api_files + 1] = _USERHOME..'/modules/lua/api'
end

-- Commands.

---
-- Patterns for auto 'end' completion for control structures.
-- @class table
-- @name control_structure_patterns
-- @see try_to_autocomplete_end
local control_structure_patterns = {
  '^%s*for', '^%s*function', '^%s*if', '^%s*repeat', '^%s*while',
  'function%s*%b()%s*$', '^%s*local%s*function'
}

---
-- Tries to autocomplete Lua's 'end' keyword for control structures like 'if',
-- 'while', 'for', etc.
-- @see control_structure_patterns
function try_to_autocomplete_end()
  local buffer = buffer
  local line_num = buffer:line_from_position(buffer.current_pos)
  local line = buffer:get_line(line_num)
  for _, patt in ipairs(control_structure_patterns) do
    if line:find(patt) then
      local indent = buffer.line_indentation[line_num]
      buffer:begin_undo_action()
      buffer:new_line()
      buffer:new_line()
      buffer:add_text(patt:find('repeat') and 'until' or 'end')
      buffer.line_indentation[line_num + 1] = indent + buffer.indent
      buffer:line_up()
      buffer:line_end()
      buffer:end_undo_action()
      return true
    end
  end
  return false
end

---
-- Determines the Lua file being 'require'd, searches through package.path for
-- that file, and opens it in Textadept.
function goto_required()
  local line = buffer:get_cur_line()
  local patterns = { 'require%s*(%b())', 'require%s*(([\'"])[^%2]+%2)' }
  local file
  for _, patt in ipairs(patterns) do
    file = line:match(patt)
    if file then break end
  end
  if not file then return end
  file = file:sub(2, -2):gsub('%.', '/')
  for path in package.path:gmatch('[^;]+') do
    path = path:gsub('?', file)
    if lfs.attributes(path) then
      io.open_file(path:iconv('UTF-8', _CHARSET))
      break
    end
  end
end

events.connect('file_after_save',
  function() -- show syntax errors as annotations
    if buffer:get_lexer() == 'lua' then
      local buffer = buffer
      buffer:annotation_clear_all()
      local text = buffer:get_text()
      text = text:gsub('^#![^\n]+', '') -- ignore shebang line
      local _, err = loadstring(text)
      if err then
        local line, msg = err:match('^.-:(%d+):%s*(.+)$')
        if line then
          buffer.annotation_visible = 2
          buffer:annotation_set_text(line - 1, msg)
          buffer.annotation_style[line - 1] = 8 -- error style number
          buffer:goto_line(line - 1)
        end
      end
    end
  end)

---
-- Container for Lua-specific key commands.
-- @class table
-- @name _G.keys.lua
_G.keys.lua = {
  al = {
    m = { io.open_file,
          (_HOME..'/modules/lua/init.lua'):iconv('UTF-8', _CHARSET) },
    g = { goto_required },
  },
  ['s\n'] = { try_to_autocomplete_end },
  [not OSX and 'ci' or '~'] = { sense.complete, sense },
  ch = { sense.show_apidoc, sense },
}

-- Snippets.

if type(_G.snippets) == 'table' then
---
-- Container for Lua-specific snippets.
-- @class table
-- @name _G.snippets.lua
  _G.snippets.lua = {
    l = "local %1(expr)%2( = %3(value))",
    p = "print(%0)",
    f = "function %1(name)(%2(args))\n\t%0\nend",
    ['for'] = "for i=%1(1), %2(10)%3(, -1) do\n\t%0\nend",
    fori = "for %1(i), %2(val) in ipairs(%3(table)) do\n\t%0\nend",
    forp = "for %1(k), %2(v) in pairs(%3(table)) do\n\t%0\nend",
  }
end