{-# LANGUAGE UnicodeSyntax, MultiParamTypeClasses #-}

module Todos.Config where

import Prelude.Unicode
import Control.Monad.Reader
import Data.Dates

import Todos.Types
import Todos.Dot
import qualified System.Console.ANSI as ANSI

-- | Any user-specified runtime config type should belong to this class
class RuntimeConfig c where
  -- | Does given TODO item match query?
  getPredicate ∷ DateTime → c → (TodoItem → 𝔹) 
  -- | Get basic configuration
  toBaseConfig ∷ c → BaseConfig

-- | Any user-specified runtime config type should include at least this properties
data BaseConfig = BConfig {
      outOnlyFirst ∷ 𝔹,           -- ^ Output only first matching entry
      outColors ∷ 𝔹,              -- ^ Show colored output
      outIds :: 𝔹,                -- ^ Show IDs
      outHighlight ∷ 𝔹,           -- ^ Highlight matching items
      sorting ∷ SortingType,      -- ^ How to sort items
      pruneL ∷ Limit, 
      minL   ∷ Limit,
      commandToRun ∷ TodoCommand,
      prefix ∷ Maybe String,      -- ^ Nothing — use default parser, Just p — use alternate parser with prefix «p»
      outputFormat ∷ String,
      indentString ∷ String,      -- ^ String to use for output tree indenting (two spaces by default)
      skipStatus ∷ 𝔹,             -- ^ Skip status field in input
      groupByFile ∷ 𝔹,
      groupByTag ∷ 𝔹,
      groupByStatus ∷ 𝔹,
      forcedStatus ∷ Maybe String,
      topStatus ∷ Maybe String
      }
    deriving (Eq, Show)

-- | Configuration for console output. Is generated in runtime from TodosConfig and Config.
data PrintConfig c = PConfig {
  printConfig ∷ c,
  printStatusColor ∷  String → (ANSI.ColorIntensity, ANSI.Color),       -- ^ Color of status field from status
  printItemColor ∷  TodoItem → Maybe (ANSI.ColorIntensity, ANSI.Color), -- ^ Color of item name
  printHighlightColor ∷ (ANSI.ColorIntensity, ANSI.Color),              -- ^ Color to use for highlighting
  doHighlight ∷ TodoItem → 𝔹                                            -- ^ Whether to highlight given item
  }

-- | User Todos config. User can specify it in @~/.config/todos/todos.hs@.
data TodosConfig c = Todos {
     parseCommandLine ∷ DateTime → c → [String] → CmdLineParseResult c,     -- ^ Function to parse command line
     filterTodos ∷ DateTime → c → [Todo] → [Todo],                          -- ^ Any function to be run to transform read TODOs tree
     statusConsoleColor ∷ String → (ANSI.ColorIntensity, ANSI.Color),       -- ^ Function to select a color of item's status field in console output
     itemConsoleColor ∷ TodoItem → Maybe (ANSI.ColorIntensity, ANSI.Color), -- ^ Function to select a color of item's name in console output
     highlightColor ∷ (ANSI.ColorIntensity, ANSI.Color),                    -- ^ Color to use for highlighting
     itemColor ∷ TodoItem → HSV,                                            -- ^ Function to select color for item's node in DOT output
     itemShape ∷ TodoItem → Shape,                                          -- ^ Function to select shape for item's node in DOT output
     printTodos ∷ PrintConfig c → [Todo] → IO (),                           -- ^ Any function to output TODOs list
     nullConfig ∷ c                                                         -- ^ Default Config (to be used without any options in command line and configs)
}

-- | Result of parsing command line
data CmdLineParseResult c = 
     Parsed c [FilePath]       -- ^ Parsed successfully, got Config and list of source files
   | ParseError String         -- ^ Some error occured
   | CmdLineHelp               -- ^ User asked for help
   deriving (Eq,Show)

-- | ask field from BaseConfig
askBase ∷ (RuntimeConfig c) ⇒ (BaseConfig → a) → Reader c a
askBase field = asks (field ∘ toBaseConfig)