{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedStrings #-}

module Yore.Repl (connect, exec, getToday, indexDay, addYears) where

import Control.Exception (bracket, throwIO)
import Control.Monad (forM)
import Data.Text (Text)
import Data.Time (Day)
import Data.Time.LocalTime (getZonedTime, localDay, zonedTimeToLocalTime)
import Text.Printf (printf)

import qualified Database.PostgreSQL.Opium as Opium

import Yore.DB (DayIndex)
import Yore.Download (downloadInto, getUrls)
import Yore.Index (createEntries)
import Yore.Time (addYears)

import qualified Yore.DB as DB

connect :: IO Opium.Connection
connect =
  Opium.connect "host=localhost port=5433 user=yore-test" >>= \case
    Left e -> error $ show e
    Right c -> pure c

exec :: (Opium.Connection -> IO a) -> IO a
exec = bracket connect Opium.close

getToday :: IO [(Text, Text)]
getToday = do
  now <- getZonedTime
  print now
  let currentDay = localDay $ zonedTimeToLocalTime now
  case addYears (-100) currentDay of
    Just then_ ->
      getUrls then_
    Nothing ->
      pure []

indexDay :: Day -> IO ()
indexDay date = exec $ \conn -> do
  either throwIO pure =<< Opium.execute_ "SELECT pg_advisory_lock(42);" conn
  printf "Checking whether %s already exists...\n" (show date)
  mbDi <- either throwIO pure =<< DB.readDayIndex date conn
  case mbDi of
    Just (_ :: DayIndex) ->
      putStrLn "Nothing to do."
    Nothing -> do
      putStrLn "Retrieving URLs..."
      urls <- getUrls date
      paths <- forM urls $ \(text, url) -> do
        printf "Downloading %s...\n" url
        (text,) <$> downloadInto "./download" url
      putStrLn "Creating DB entries..."
      createEntries date paths conn
      putStrLn "Done."