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

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

--- Handles file-specific settings (based on file extension).
module('textadept.mime_types', package.seeall)

---
-- [Local table] File extensions with their associated lexers.
-- @class table
-- @name extensions
local extensions = {}

---
-- [Local table] Shebang words and their associated lexers.
-- @class table
-- @name shebangs
local shebangs = {}

---
-- [Local table] First-line patterns and their associated lexers.
-- @class table
-- @name patterns
local patterns = {}

-- Load mime-types from mime_types.conf
local f = io.open(_HOME..'/core/ext/mime_types.conf', 'rb')
if f then
  for line in f:lines() do
    if not line:find('^%s*%%') then
      if line:find('^%s*[^#/]') then -- extension definition
        local ext, lexer_name = line:match('^%s*(.+)%s+(%S+)$')
        if ext and lexer_name then extensions[ext] = lexer_name end
      else -- shebang or pattern
        local ch, text, lexer_name = line:match('^%s*([#/])(.+)%s+(%S+)$')
        if ch and text and lexer_name then
          (ch == '#' and shebangs or patterns)[text] = lexer_name
        end
      end
    end
  end
  f:close()
end

---
-- [Local function] Sets the buffer's lexer based on filename, shebang words, or
-- first line pattern.
local function set_lexer()
  local lexer
  if buffer.filename then
    lexer = extensions[buffer.filename:match('[^/\\.]+$')]
  end
  if not lexer then
    local line = buffer:get_line(0)
    if line:find('^#!') then
      for word in line:gsub('[/\\]', ' '):gmatch('%S+') do
        if shebangs[word] then
          lexer = shebangs[word]
          break
        end
      end
    end
    if not lexer then
      for patt, lex in pairs(patterns) do
        if line:find(patt) then
          lexer = lex
          break
        end
      end
    end
  end
  buffer:set_lexer_language(lexer or 'container')
end

---
-- [Local function] Performs actions suitable for a new buffer.
-- Sets the buffer's lexer language and loads the language module.
local function handle_new()
  set_lexer()
  if buffer.filename then
    local lang = extensions[buffer.filename:match('[^/\\.]+$')]
    if lang then
      local ret, err = pcall(require, lang)
      if ret then
        _m[lang].set_buffer_properties()
      elseif not ret and not err:find("^module '"..lang.."' not found:") then
        textadept.events.error(err)
      end
    end
  end
end

textadept.events.add_handler('file_opened', handle_new)
textadept.events.add_handler('file_saved_as', handle_new)
textadept.events.add_handler('buffer_switch', set_lexer)
textadept.events.add_handler('view_new', set_lexer)