"=============================================================================
" FILE: alias.vim
" AUTHOR:  Shougo Matsushita <Shougo.Matsu at gmail.com>
"          tacroe <tacroe at gmail.com>
" License: MIT license
"=============================================================================

let s:save_cpo = &cpo
set cpo&vim

call unite#util#set_default('g:unite_source_alias_aliases', {})

function! unite#sources#alias#define() abort
  return s:make_aliases()
endfunction

function! s:make_aliases() abort
  let aliases = []

  let user_aliases = map(copy(g:unite_source_alias_aliases),
        \ "type(v:val) == type('') ? { 'source' : v:val } : v:val")
  for [name, config] in items(user_aliases)
    let args =
          \ (!has_key(config, 'args')) ? [] :
          \ (type(config.args) == type([])) ?
          \ config.args : [config.args]

    let alias = {}
    let alias.name = name
    let alias.description = get(config, 'description',
          \ s:make_default_description(config.source, args))
    let alias.source__config = config
    let alias.source__args = args
    let alias.hooks = {}

    function! alias.hooks.on_pre_init(args, context) abort
      let config = a:context.source.source__config
      let original_source =
            \ (!has_key(config, 'source') ||
            \  config.source ==# a:context.source.name) ? {} :
            \ deepcopy(unite#get_all_sources(config.source))
      let alias_source = deepcopy(a:context.source)

      if has_key(original_source, 'hooks')
            \ && has_key(original_source.hooks, 'on_pre_init')
        " Call pre init hook.
        call original_source.hooks.on_pre_init(
              \ a:context.source.source__args + a:args,
              \ { 'source' : original_source })
      endif

      let source = extend(a:context.source,
            \ filter(copy(original_source),
            \ 'type(v:val) != type(function("type"))'))
      let source.name = alias_source.name
      let source.description = alias_source.description
      let source.hooks = {}
      let source.source__original_source = original_source
      let source.source__args = a:context.source.source__args

      " Overwrite hooks.
      if has_key(original_source, 'hooks')
        for func in filter(keys(original_source.hooks),
              \ 'v:val !=# "on_pre_init"')
          let define_function = join([
                \ 'function! source.hooks.' . func . '(args, context)',
                \ '  let args = a:context.source.source__args + a:args',
                \ '  return a:context.source.source__original_source.hooks.'
                \                    . func . '(args, a:context)',
                \ 'endfunction'], "\n")
          execute define_function
        endfor
      endif

      " Overwrite functions.
      for func in keys(filter(copy(original_source),
            \ 'type(v:val) == type(function("type"))'))
        if func ==# 'complete'
          let define_function = join([
                \ 'function! source.' . func . '(args, context, arglead, cmdline, cursorpos)',
                \ '  let args = self.source__args + a:args',
                \ '  return self.source__original_source.'
                \                    . func .
                \   '(args, a:context, a:arglead, a:cmdline, a:cursorpos)',
                \ 'endfunction'], "\n")
        else
          let define_function = join([
                \ 'function! source.' . func . '(args, context)',
                \ '  let args = self.source__args + a:args',
                \ '  return self.source__original_source.'
                \                    . func . '(args, a:context)',
                \ 'endfunction'], "\n")
        endif
        execute define_function
      endfor
    endfunction

    call add(aliases, alias)
  endfor

  return aliases
endfunction

function! s:make_default_description(source_name, args) abort
  let desc = 'alias for "' . a:source_name
  if empty(a:args)
    return desc . '"'
  endif

  let desc .= ':' . join(a:args, ':') . '"'
  return desc
endfunction

let &cpo = s:save_cpo
unlet s:save_cpo