{-# LANGUAGE DeriveGeneric, OverloadedStrings #-}
module VimScript where

import Data.Char (isAlpha, isAlphaNum, ord, toLower)
import Data.Function (on)
import Data.List (foldl', groupBy, sort, sortBy, nub)
import qualified Data.Map.Strict as M
import Data.Text (Text, singleton, unpack, unwords)
import qualified Data.Text as T
import Prelude hiding (show, unwords)

import Cmdline
import qualified Command as C
import qualified Mapping as M
import Mode
import qualified Plugin as P
import qualified Setting as S
import ShowText

data VimScript = VimScript (M.Map Place [Text])
               deriving (Eq)

data Place = Plugin
           | Autoload Text
           | Ftplugin Text
           | Syntax   Text
           deriving (Eq, Ord)

instance ShowText Place where
  show Plugin        = "plugin/miv.vim"
  show (Autoload "") = "autoload/miv.vim"
  show (Autoload s)  = "autoload/miv/" <> s <> ".vim"
  show (Ftplugin s)  = "ftplugin/" <> s <> ".vim"
  show (Syntax s)    = "syntax/" <> s <> ".vim"

vimScriptToList :: VimScript -> [(Place, [Text])]
vimScriptToList (VimScript x) = M.toList x

instance Semigroup VimScript where
  VimScript x <> VimScript y
    | M.null x = VimScript y
    | M.null y = VimScript x
    | otherwise = VimScript (M.unionWith concat' x y)
    where
      concat' a [] = a
      concat' [] b = b
      concat' a b = a <> [""] <> b

instance Monoid VimScript where
  mempty = VimScript M.empty

gatherScript :: S.Setting -> VimScript
gatherScript setting = beforeScript setting
                    <> gatherBeforeAfterScript plugins
                    <> gather' "dependon" P.dependon P.loadbefore plugins
                    <> gather' "dependedby" P.dependedby P.loadafter plugins
                    <> gather "mappings" P.mappings plugins
                    <> gather "mapmodes" (map show . P.mapmodes) plugins
                    <> gather "functions" P.functions plugins
                    <> pluginLoader
                    <> mappingLoader
                    <> commandLoader
                    <> foldl' (<>) mempty (map pluginConfig plugins)
                    <> filetypeLoader setting
                    <> funcUndefinedLoader setting
                    <> cmdlineEnterLoader setting
                    <> insertEnterLoader setting
                    <> filetypeScript setting
                    <> syntaxScript setting
                    <> afterScript setting
  where plugins = S.plugins setting

gatherBeforeAfterScript :: [P.Plugin] -> VimScript
gatherBeforeAfterScript x = insertAuNameMap $ gatherScripts x (mempty, M.empty)
  where
    insertAuNameMap :: (VimScript, M.Map Text Text) -> VimScript
    insertAuNameMap (vs, m) = VimScript (M.singleton (Autoload "") $
          [ "let s:autoload = {" ]
       <> [ "      \\ " <> singleQuote k <> ": " <> singleQuote a <> "," | (k, a) <- M.toList m ]
       <> [ "      \\ }" ]) <> vs
    gatherScripts :: [P.Plugin] -> (VimScript, M.Map Text Text) -> (VimScript, M.Map Text Text)
    gatherScripts (p:ps) (vs, m)
            | null (P.before p) && null (P.after p) = gatherScripts ps (vs, m)
            | otherwise = gatherScripts ps (vs <> vs', M.insert name hchar m)
      where
        name = T.filter isAlphaNum (T.toLower (show p))
        hchar | null (loadScript p) = maybe "_" singleton $ getHeadChar $ show p
              | otherwise = "_"
        funcname str = "miv#" <> hchar <> "#" <> str <> "_" <> name
        vs' = VimScript $ M.singleton (Autoload hchar) $
          wrapFunction (funcname "before") (P.before p) <>
          wrapFunction (funcname "after") (P.after p)
    gatherScripts [] (vs, m) = (vs, m)

gather :: Text -> (P.Plugin -> [Text]) -> [P.Plugin] -> VimScript
gather name f plg
  = VimScript (M.singleton (Autoload "") $
      [ "let s:" <> name <> " = {" ]
   <> [ "      \\ " <> singleQuote (show p)
                    <> ": [ " <> T.intercalate ", " (map singleQuote (f p))  <> " ],"
        | p <- plg, enabled p, not (null (f p)) ]
   <> [ "      \\ }" ])
  where enabled p = P.enable p /= "0"

gather' :: Text -> (P.Plugin -> [Text]) -> (P.Plugin -> [Text]) -> [P.Plugin] -> VimScript
gather' name f g plg
  = VimScript (M.singleton (Autoload "") $
      [ "let s:" <> name <> " = {" ]
   <> [ "      \\ " <> singleQuote p
                    <> ": [ " <> T.intercalate ", " (map singleQuote $ sort $ nub q)  <> " ],"
        | (p, q) <- collectSndByFst $ [ (show p, q) | p <- plg, enabled p, q <- f p ]
                                   <> [ (q, show p) | p <- plg, enabled p, q <- g p ] ]
   <> [ "      \\ }" ])
  where enabled p = P.enable p /= "0"

collectSndByFst :: Ord a => [(a,b)] -> [(a,[b])]
collectSndByFst xs = [ (fst (ys !! 0), map snd ys)
                       | ys <- groupBy ((==) `on` fst) $ sortBy (compare `on'` fst) xs ]
  where on' f g x y = g x `f` g y

pluginConfig :: P.Plugin -> VimScript
pluginConfig plg
    = VimScript (M.singleton Plugin $ wrapInfo $
        wrapEnable (P.enable plg) $ mapleader <> gatherCommand plg <> gatherMapping plg <> P.script plg <> loadScript plg)
  where
    wrapInfo [] = []
    wrapInfo str = ("\" " <> P.name plg) : str
    mapleader = (\s -> if T.null s then [] else ["let g:mapleader = " <> singleQuote s]) (P.mapleader plg)

loadScript :: P.Plugin -> [Text]
loadScript plg
  | all null [ P.commands plg, P.mappings plg, P.functions plg, P.filetypes plg
             , P.loadafter plg, P.loadbefore plg ] && null (P.cmdlines plg) && not (P.insert plg)
  = ["call miv#load(" <> singleQuote (show plg) <> ")"]
  | otherwise = []

gatherCommand :: P.Plugin -> [Text]
gatherCommand plg
  | not (null (P.commands plg))
    = [show C.defaultCommand
          { C.cmdName = c,
            C.cmdRepText = unwords [
              "call miv#command(" <> singleQuote (show plg) <> ",",
              singleQuote c <> ",",
              singleQuote "<bang>" <> ",",
              "<q-args>,",
              "expand('<line1>'),",
              "expand('<line2>'))"
          ] } | c <- P.commands plg]
  | otherwise = []

gatherMapping :: P.Plugin -> [Text]
gatherMapping plg
  | not (null (P.mappings plg))
    = [show M.defaultMapping
          { M.mapName = mapping,
            M.mapRepText = escape mode <> ":<C-u>call miv#mapping("
                <> singleQuote (show plg) <> ", "
                <> singleQuote mapping <> ", "
                <> singleQuote (show mode) <> ")<CR>",
            M.mapMode = mode
          } | mapping <- P.mappings plg, mode <- modes]
  | otherwise = []
    where modes = if null (P.mapmodes plg) then [NormalMode] else P.mapmodes plg
          escape mode = if mode `elem` [InsertMode, OperatorPendingMode] then "<ESC>" else ""

beforeScript :: S.Setting -> VimScript
beforeScript setting = VimScript (M.singleton Plugin (S.before setting))

afterScript :: S.Setting -> VimScript
afterScript setting = VimScript (M.singleton Plugin (S.after setting))

filetypeLoader :: S.Setting -> VimScript
filetypeLoader setting
  = mconcat $ map (uncurry f) $
      collectSndByFst [(ft, p) | p <- S.plugins setting, ft <- P.filetypes p]
  where
    f :: Text -> [P.Plugin] -> VimScript
    f ft plugins = flip foldMap (getHeadChar ft) $
      \c -> let funcname = "miv#" <> singleton c <> "#load_" <> T.filter isAlphaNum (T.toLower ft)
                in VimScript (M.singleton Plugin
                     [ "augroup miv-file-type-" <> ft
                     , "  autocmd!"
                     , "  autocmd FileType " <> ft <> " call " <> funcname <> "()"
                     , "augroup END" ]) <>
                   VimScript (M.singleton (Autoload (singleton c)) $
                     ("function! " <> funcname <> "() abort")
                     : "  setlocal filetype="
                     : loadPlugins plugins
                  <> [ "  autocmd! miv-file-type-" <> ft
                     , "  augroup! miv-file-type-" <> ft
                     , "  setlocal filetype=" <> ft
                     , "  silent! doautocmd FileType " <> ft
                     , "endfunction" ])

wrapEnable :: Text -> [Text] -> [Text]
wrapEnable enable str
  | null str = []
  | T.null enable = str
  | enable == "0" = []
  | otherwise = (indent <> "if " <> enable)
                           : map ("  "<>) str
             <> [indent <> "endif"]
  where indent = T.takeWhile (==' ') (head str)

loadPlugins :: [P.Plugin] -> [Text]
loadPlugins plugins = concat
  [wrapEnable enable
    ["  call miv#load(" <> singleQuote (show p) <> ")" | p <- plugins']
      | (enable, plugins') <- collectSndByFst [(P.enable p, p) | p <- plugins]]

singleQuote :: Text -> Text
singleQuote str = "'" <> str <> "'"

filetypeScript :: S.Setting -> VimScript
filetypeScript = foldMap (\(ft, src) -> VimScript (M.singleton (Ftplugin ft) src)) . M.toList . S.filetype

syntaxScript :: S.Setting -> VimScript
syntaxScript = foldMap (\(ft, src) -> VimScript (M.singleton (Syntax ft) src)) . M.toList . S.syntax

wrapFunction :: Text -> [Text] -> [Text]
wrapFunction funcname script =
     ["function! " <> funcname <> "() abort"]
  <> map ("  "<>) script
  <> ["endfunction"]

getHeadChar :: Text -> Maybe Char
getHeadChar xs
  | T.null xs = Nothing
  | otherwise = let x = T.head xs in if isAlpha x then Just (toLower x) else getHeadChar (T.tail xs)

mappingLoader :: VimScript
mappingLoader = VimScript (M.singleton (Autoload "")
  [ "function! miv#mapping(name, mapping, mode) abort"
  , "  call miv#load(a:name)"
  , "  if a:mode ==# 'v' || a:mode ==# 'x'"
  , "    call feedkeys('gv', 'n')"
  , "  elseif a:mode ==# 'o'"
  , "    call feedkeys(\"\\<Esc>\", 'n')"
  , "    call feedkeys(v:operator, 'm')"
  , "  endif"
  , "  call feedkeys((v:count ? v:count : '') . substitute(a:mapping, '<Plug>', \"\\<Plug>\", 'g'), 'm')"
  , "  return ''"
  , "endfunction" ])

commandLoader :: VimScript
commandLoader = VimScript (M.singleton (Autoload "")
  [ "function! miv#command(name, command, bang, args, line1, line2) abort"
  , "  silent! execute 'delcommand' a:command"
  , "  call miv#load(a:name)"
  , "  let range = a:line1 != a:line2 ? a:line1.','.a:line2 : ''"
  , "  try"
  , "    exec range.a:command.a:bang a:args"
  , "  catch /^Vim\\%((\\a\\+)\\)\\=:E481:/"
  , "    exec a:command.a:bang a:args"
  , "  endtry"
  , "endfunction" ])

funcUndefinedLoader :: S.Setting -> VimScript
funcUndefinedLoader setting = if null functions then mempty else
  VimScript (M.singleton Plugin
  [ "\" FuncUndefined"
  , "augroup miv-func-undefined"
  , "  autocmd!"
  , "  autocmd FuncUndefined * call miv#func_undefined(expand('<amatch>'))"
  , "augroup END" ])
  <> VimScript (M.singleton (Autoload "")
  [ "function! miv#func_undefined(pattern) abort"
  , "  if a:pattern !~# " <> singleQuote (T.intercalate "\\|" functions)
  , "    return"
  , "  endif"
  , "  if empty(s:functions)"
  , "    autocmd! miv-func-undefined"
  , "    augroup! miv-func-undefined"
  , "    return"
  , "  endif"
  , "  for [name, fs] in items(s:functions)"
  , "    for f in fs"
  , "      if a:pattern =~# f"
  , "        call miv#load(name)"
  , "        return"
  , "      endif"
  , "    endfor"
  , "  endfor"
  , "endfunction" ])
  where functions = [ f | p <- S.plugins setting, f <- P.functions p ]

cmdlineEnterLoader :: S.Setting -> VimScript
cmdlineEnterLoader setting
  = mconcat $ map (uncurry f) $
      collectSndByFst [(cmdline, p) | p <- S.plugins setting, cmdline <- P.cmdlines p]
  where
    f :: Cmdline -> [P.Plugin] -> VimScript
    f cmdline plugins = VimScript (M.singleton Plugin
      [ "\" CmdlineEnter " <> (show cmdline)
      , "if exists('#CmdlineEnter')"
      , "  augroup " <> group
      , "    autocmd!"
      , "    autocmd CmdlineEnter " <> (cmdlinePattern cmdline) <> " call miv#cmdline_enter_" <> c <> "()"
      , "  augroup END"
      , "else"
      , "  call miv#cmdline_enter_" <> c <> "()"
      , "endif" ])
      <> VimScript (M.singleton (Autoload "") $
       ("function! miv#cmdline_enter_" <> c <> "() abort")
      : loadPlugins plugins
      <> [ "  if exists('#CmdlineEnter')"
      , "    autocmd! " <> group
      , "    augroup! " <> group
      , "  endif"
      , "endfunction" ])
      where c = T.concat $ map (show . ord) (unpack (show cmdline))
            group = "miv-cmdline-enter-" <> c

insertEnterLoader :: S.Setting -> VimScript
insertEnterLoader setting = if null plugins then mempty else
  VimScript (M.singleton Plugin
  [ "\" InsertEnter"
  , "augroup miv-insert-enter"
  , "  autocmd!"
  , "  autocmd InsertEnter * call miv#insert_enter()"
  , "augroup END" ])
  <> VimScript (M.singleton (Autoload "")
  $ "function! miv#insert_enter() abort"
  : loadPlugins plugins
  <> [ "  autocmd! miv-insert-enter"
  , "  augroup! miv-insert-enter"
  , "  silent! doautocmd InsertEnter"
  , "endfunction" ])
  where plugins = filter P.insert (S.plugins setting)

pluginLoader :: VimScript
pluginLoader = VimScript (M.singleton (Autoload "")
  [ "let s:loaded = {}"
  , "let s:path = expand('<sfile>:p:h:h')"
  , "let s:mivpath = expand('<sfile>:p:h:h:h') . '/'"
  , "let s:rtpidx = 0"
  , "function! miv#load(name) abort"
  , "  if has_key(s:loaded, a:name)"
  , "    return"
  , "  endif"
  , "  let s:loaded[a:name] = 1"
  , "  if has_key(s:functions, a:name)"
  , "    call remove(s:functions, a:name)"
  , "  endif"
  , "  for n in get(s:dependon, a:name, [])"
  , "    call miv#load(n)"
  , "  endfor"
  , "  for mode in get(s:mapmodes, a:name, ['n'])"
  , "    for mapping in get(s:mappings, a:name, [])"
  , "      silent! execute mode . 'unmap' mapping"
  , "    endfor"
  , "  endfor"
  , "  let name = substitute(tolower(a:name), '[^a-z0-9]', '', 'g')"
  , "  let au = has_key(s:autoload, name)"
  , "  if au"
  , "    call miv#{s:autoload[name]}#before_{name}()"
  , "  endif"
  , "  let newrtp = s:mivpath . a:name"
  , "  if !isdirectory(newrtp)"
  , "    return"
  , "  endif"
  , "  let rtps = split(&rtp, ',')"
  , "  let s:rtpidx = max([index(rtps, s:path, s:rtpidx), 0])"
  , "  let &rtp = join(insert(rtps, newrtp, s:rtpidx), ',')"
  , "  if isdirectory(newrtp . '/after')"
  , "    exec 'set rtp+=' . newrtp . '/after'"
  , "  endif"
  , "  for dir in filter(['/plugin', '/after/plugin'], 'isdirectory(newrtp . v:val)')"
  , "    for file in split(glob(newrtp . dir . '/**/*.vim'), '\\n')"
  , "      silent! source `=file`"
  , "    endfor"
  , "  endfor"
  , "  if au"
  , "    call miv#{s:autoload[name]}#after_{name}()"
  , "  endif"
  , "  for n in get(s:dependedby, a:name, [])"
  , "    call miv#load(n)"
  , "  endfor"
  , "endfunction" ])