{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE QuasiQuotes #-}

module PGExtras.Queries.IndexSize (indexSizeSQL, displayIndexSize) where

import PGExtras.Helpers (maybeText)
import Database.PostgreSQL.Simple
import Text.RawString.QQ
import qualified Data.Text as Text
import Control.Monad (forM_)
import Data.List (intercalate)

indexSizeSQL :: Query
indexSizeSQL :: Query
indexSizeSQL = [r|SELECT c.relname AS name,
  pg_size_pretty(sum(c.relpages::bigint*8192)::bigint) AS size
FROM pg_class c
LEFT JOIN pg_namespace n ON (n.oid = c.relnamespace)
WHERE n.nspname NOT IN ('pg_catalog', 'information_schema')
AND n.nspname !~ '^pg_toast'
AND c.relkind='i'
GROUP BY c.relname
ORDER BY sum(c.relpages) DESC;|]

displayIndexSize :: [(Maybe Text.Text, Maybe Text.Text)] -> IO ()
displayIndexSize :: [(Maybe Text, Maybe Text)] -> IO ()
displayIndexSize rows :: [(Maybe Text, Maybe Text)]
rows = do
  String -> IO ()
putStrLn (String -> IO ()) -> String -> IO ()
forall a b. (a -> b) -> a -> b
$ String
description
  String -> IO ()
putStrLn (String -> IO ()) -> String -> IO ()
forall a b. (a -> b) -> a -> b
$ String -> [String] -> String
forall a. [a] -> [[a]] -> [a]
intercalate " | " [String]
tableHeaders
  [(Maybe Text, Maybe Text)]
-> ((Maybe Text, Maybe Text) -> IO ()) -> IO ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_ [(Maybe Text, Maybe Text)]
rows (((Maybe Text, Maybe Text) -> IO ()) -> IO ())
-> ((Maybe Text, Maybe Text) -> IO ()) -> IO ()
forall a b. (a -> b) -> a -> b
$ \(arg1 :: Maybe Text
arg1, arg2 :: Maybe Text
arg2) ->
    String -> IO ()
putStrLn (String -> IO ()) -> String -> IO ()
forall a b. (a -> b) -> a -> b
$ Maybe Text -> String
maybeText(Maybe Text
arg1) String -> String -> String
forall a. [a] -> [a] -> [a]
++ " | " String -> String -> String
forall a. [a] -> [a] -> [a]
++ Maybe Text -> String
maybeText(Maybe Text
arg2)

description :: [Char]
description :: String
description = "The size of indexes, descending by size"

tableHeaders :: [[Char]]
tableHeaders :: [String]
tableHeaders = ["name", "ratio"]