{- | Rendering & misc. helpers. -}

{-# LANGUAGE OverloadedStrings #-}

module Hledger.UI.UIUtils
where

import Brick
import Brick.Widgets.Border
import Brick.Widgets.Border.Style
import Brick.Widgets.Dialog
import Brick.Widgets.Edit
import Data.List
import Data.Monoid
import Graphics.Vty
import Lens.Micro.Platform

import Hledger
import Hledger.UI.UITypes
import Hledger.UI.UIState

-- | Draw the help dialog, called when help mode is active.
helpDialog :: Widget
helpDialog =
  Widget Fixed Fixed $ do
    c <- getContext
    render $
      renderDialog (dialog "help" (Just "Help (h/ESC to close)") Nothing (c^.availWidthL - 2)) $ -- (Just (0,[("ok",())]))
      padTopBottom 1 $ padLeftRight 1 $
      hBox [
         (padLeftRight 1 $
           vBox [
             str "MISC"
            ,renderKey ("h", "toggle help")
            ,renderKey ("a", "add transaction")
            ,renderKey ("g", "reload data")
            ,renderKey ("q", "quit")
            ,str " "
            ,str "NAVIGATION"
            ,renderKey ("UP/DOWN/PGUP/PGDN/HOME/END", "")
            ,str "  move selection"
            ,renderKey ("RIGHT/ENTER", "drill down")
            ,renderKey ("LEFT", "previous screen")
            ,renderKey ("ESC", "cancel / reset")
            ]
        )
        ,(padLeftRight 1 $
           vBox [
             str "FILTERING"
            ,renderKey ("/", "set a filter query")
            ,renderKey ("C", "toggle cleared filter")
            ,renderKey ("U", "toggle uncleared filter")
            ,renderKey ("R", "toggle real filter")
            ,renderKey ("Z", "toggle nonzero filter")
            ,renderKey ("F", "toggle flat/exclusive mode")
            ,renderKey ("DEL/BS", "remove filters")
            ,str "accounts screen:"
            ,renderKey ("-+0123456789", "set depth limit")
            ]
        )
      ]
  where
    renderKey (key,desc) = withAttr (borderAttr <> "keys") (str key) <+> str " " <+> str desc

-- | Event handler used when help mode is active.
helpHandle :: UIState -> Event -> EventM (Next UIState)
helpHandle ui ev =
  case ev of
    EvKey k [] | k `elem` [KEsc, KChar 'h'] -> continue $ setMode Normal ui
    _ -> continue ui

-- | Draw the minibuffer.
minibuffer :: Editor -> Widget
minibuffer ed =
  forceAttr (borderAttr <> "minibuffer") $
  hBox $
  [txt "filter: ", renderEditor ed]

-- | Wrap a widget in the default hledger-ui screen layout.
defaultLayout :: Widget -> Widget -> Widget -> Widget
defaultLayout toplabel bottomlabel =
  topBottomBorderWithLabels (str " "<+>toplabel<+>str " ") (str " "<+>bottomlabel<+>str " ") .
  margin 1 0 Nothing
  -- topBottomBorderWithLabel2 label .
  -- padLeftRight 1 -- XXX should reduce inner widget's width by 2, but doesn't
                    -- "the layout adjusts... if you use the core combinators"

borderQueryStr :: String -> Widget
borderQueryStr ""  = str ""
borderQueryStr qry = str " matching " <+> withAttr (borderAttr <> "query") (str qry)

borderDepthStr :: Maybe Int -> Widget
borderDepthStr Nothing  = str ""
borderDepthStr (Just d) = str " to " <+> withAttr (borderAttr <> "query") (str $ "depth "++show d)

borderKeysStr :: [(String,String)] -> Widget
borderKeysStr keydescs =
  hBox $
  intersperse sep $
  [withAttr (borderAttr <> "keys") (str keys) <+> str ":" <+> str desc | (keys, desc) <- keydescs]
  where
    -- sep = str " | "
    sep = str " "

-- temporary shenanigans:

-- | Convert the special account name "*" (from balance report with depth limit 0) to something clearer.
replaceHiddenAccountsNameWith :: AccountName -> AccountName -> AccountName
replaceHiddenAccountsNameWith anew a | a == hiddenAccountsName = anew
                                     | a == "*"                = anew
                                     | otherwise               = a

hiddenAccountsName = "..." -- for now

-- generic

topBottomBorderWithLabel :: Widget -> Widget -> Widget
topBottomBorderWithLabel label = \wrapped ->
  Widget Greedy Greedy $ do
    c <- getContext
    let (_w,h) = (c^.availWidthL, c^.availHeightL)
        h' = h - 2
        wrapped' = vLimit (h') wrapped
        debugmsg =
          ""
          -- "  debug: "++show (_w,h')
    render $
      hBorderWithLabel (label <+> str debugmsg)
      <=>
      wrapped'
      <=>
      hBorder

topBottomBorderWithLabels :: Widget -> Widget -> Widget -> Widget
topBottomBorderWithLabels toplabel bottomlabel = \wrapped ->
  Widget Greedy Greedy $ do
    c <- getContext
    let (_w,h) = (c^.availWidthL, c^.availHeightL)
        h' = h - 2
        wrapped' = vLimit (h') wrapped
        debugmsg =
          ""
          -- "  debug: "++show (_w,h')
    render $
      hBorderWithLabel (toplabel <+> str debugmsg)
      <=>
      wrapped'
      <=>
      hBorderWithLabel bottomlabel

-- XXX should be equivalent to the above, but isn't (page down goes offscreen)
_topBottomBorderWithLabel2 :: Widget -> Widget -> Widget
_topBottomBorderWithLabel2 label = \wrapped ->
 let debugmsg = ""
 in hBorderWithLabel (label <+> str debugmsg)
    <=>
    wrapped
    <=>
    hBorder

-- XXX superseded by pad, in theory
-- | Wrap a widget in a margin with the given horizontal and vertical
-- thickness, using the current background colour or the specified
-- colour.
-- XXX May disrupt border style of inner widgets.
-- XXX Should reduce the available size visible to inner widget, but doesn't seem to (cf rsDraw2).
margin :: Int -> Int -> Maybe Color -> Widget -> Widget
margin h v mcolour = \w ->
  Widget Greedy Greedy $ do
    c <- getContext
    let w' = vLimit (c^.availHeightL - v*2) $ hLimit (c^.availWidthL - h*2) w
        attr = maybe currentAttr (\c -> c `on` c) mcolour
    render $
      withBorderAttr attr $
      withBorderStyle (borderStyleFromChar ' ') $
      applyN v (hBorder <=>) $
      applyN h (vBorder <+>) $
      applyN v (<=> hBorder) $
      applyN h (<+> vBorder) $
      w'

   -- withBorderAttr attr .
   -- withBorderStyle (borderStyleFromChar ' ') .
   -- applyN n border

withBorderAttr :: Attr -> Widget -> Widget
withBorderAttr attr = updateAttrMap (applyAttrMappings [(borderAttr, attr)])