{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE TupleSections #-}

module Simplex.Messaging.Agent.Store.SQLite.Migrations
  ( Migration (..),
    app,
    initialize,
    get,
    run,
  )
where

import Control.Monad (forM_)
import Data.FileEmbed (embedDir, makeRelativeToProject)
import Data.Function (on)
import Data.List (intercalate, sortBy)
import Data.Text (Text)
import Data.Text.Encoding (decodeUtf8)
import Data.Time.Clock (getCurrentTime)
import Database.SQLite.Simple (Connection, Only (..))
import qualified Database.SQLite.Simple as DB
import Database.SQLite.Simple.QQ (sql)
import qualified Database.SQLite3 as SQLite3
import System.FilePath (takeBaseName, takeExtension)

data Migration = Migration {name :: String, up :: Text}
  deriving (Show)

-- | The list of migrations in ascending order by date
app :: [Migration]
app =
  sortBy (compare `on` name) . map migration . filter sqlFile $
    $(makeRelativeToProject "migrations" >>= embedDir)
  where
    sqlFile (file, _) = takeExtension file == ".sql"
    migration (file, qStr) = Migration {name = takeBaseName file, up = decodeUtf8 qStr}

get :: Connection -> [Migration] -> IO (Either String [Migration])
get conn migrations =
  migrationsToRun migrations . map fromOnly
    <$> DB.query_ conn "SELECT name FROM migrations ORDER BY name ASC;"

run :: Connection -> [Migration] -> IO ()
run conn ms = DB.withImmediateTransaction conn . forM_ ms $
  \Migration {name, up} -> insert name >> execSQL up
  where
    insert name = DB.execute conn "INSERT INTO migrations (name, ts) VALUES (?, ?);" . (name,) =<< getCurrentTime
    execSQL = SQLite3.exec $ DB.connectionHandle conn

initialize :: Connection -> IO ()
initialize conn =
  DB.execute_
    conn
    [sql|
      CREATE TABLE IF NOT EXISTS migrations (
        name TEXT NOT NULL,
        ts TEXT NOT NULL,
        PRIMARY KEY (name)
      );
    |]

migrationsToRun :: [Migration] -> [String] -> Either String [Migration]
migrationsToRun appMs [] = Right appMs
migrationsToRun [] dbMs = Left $ "database version is newer than the app: " <> intercalate ", " dbMs
migrationsToRun (a : as) (d : ds)
  | name a == d = migrationsToRun as ds
  | otherwise = Left $ "different migration in the app/database: " <> name a <> " / " <> d