testDatabases <- c("postgresql")

if (Sys.getenv("CDM5_POSTGRESQL_SERVER") != "") {
  library(DatabaseConnector)

  if (dir.exists(Sys.getenv("DATABASECONNECTOR_JAR_FOLDER"))) {
    jdbcDriverFolder <- Sys.getenv("DATABASECONNECTOR_JAR_FOLDER")
  } else {
    jdbcDriverFolder <- file.path(tempdir(), "jdbcDrivers")
    dir.create(jdbcDriverFolder, showWarnings = FALSE)
    DatabaseConnector::downloadJdbcDrivers("all", pathToDriver = jdbcDriverFolder)

    Sys.setenv(DATABASECONNECTOR_JAR_FOLDER = jdbcDriverFolder)

    withr::defer({
      unlink(jdbcDriverFolder,
             recursive = TRUE,
             force = TRUE)
    },
    testthat::teardown_env())
  }
} else {
  message("Skipping driver setup because environmental variables not set")
}

# Helper functions used in tests
getConnectionDetails <- function(dbms) {
  switch (
    dbms,
    "postgresql" = createConnectionDetails(
      dbms = "postgresql",
      user = Sys.getenv("CDMDDLBASE_POSTGRESQL_USER"),
      password = Sys.getenv("CDMDDLBASE_POSTGRESQL_PASSWORD"),
      server = Sys.getenv("CDMDDLBASE_POSTGRESQL_SERVER"),
      pathToDriver = jdbcDriverFolder
    ),
    "redshift" = createConnectionDetails(
      dbms = "redshift",
      user = Sys.getenv("CDMDDLBASE_REDSHIFT_USER"),
      password = Sys.getenv("CDMDDLBASE_REDSHIFT_PASSWORD"),
      server = Sys.getenv("CDMDDLBASE_REDSHIFT_SERVER"),
      pathToDriver = jdbcDriverFolder
    ),
    "sql server" = createConnectionDetails(
      dbms = "sql server",
      user = Sys.getenv("CDMDDLBASE_SQL_SERVER_USER"),
      password = Sys.getenv("CDMDDLBASE_SQL_SERVER_PASSWORD"),
      server = Sys.getenv("CDMDDLBASE_SQL_SERVER_SERVER"),
      pathToDriver = jdbcDriverFolder
    ),
    "oracle" = createConnectionDetails(
      dbms = "oracle",
      user = Sys.getenv("CDMDDLBASE_ORACLE_USER"),
      password = Sys.getenv("CDMDDLBASE_ORACLE_PASSWORD"),
      server = Sys.getenv("CDMDDLBASE_ORACLE_SERVER"),
      pathToDriver = jdbcDriverFolder
    )
  )
}

getSchema <- function(dbms) {
  switch (
    dbms,
    "postgresql" = Sys.getenv("CDMDDLBASE_POSTGRESQL_SCHEMA"),
    "redshift" = Sys.getenv("CDMDDLBASE_REDSHIFT_SCHEMA"),
    "sql server" = Sys.getenv("CDMDDLBASE_SQL_SERVER_CDM_SCHEMA"),
    "oracle" = Sys.getenv("CDMDDLBASE_ORACLE_CDM_SCHEMA")
  )
}

listTablesInSchema <- function(connectionDetails, schema) {
  stopifnot(
    "ConnectionDetails" %in% class(connectionDetails),
    class(schema) == "character",
    length(schema) == 1
  )
  stopifnot(connectionDetails$dbms %in% c("postgresql", "redshift", "sql server", "oracle"))
  con <- DatabaseConnector::connect(connectionDetails)
  on.exit(DatabaseConnector::disconnect(con))
  dbms <- connectionDetails$dbms
  if (dbms %in% c("postgresql", "redshift", "sql server")) {
    tables <-
      dbGetQuery(
        con,
        paste0(
          "select table_name from information_schema.tables where table_schema = '",
          schema,
          "'"
        )
      )[[1]]
  } else if (dbms == "oracle") {
    query <-
      paste0(
        "select table_name from all_tables where owner = '",
        toupper(schema),
        "' and tablespace_name = 'USERS'"
      )
    tables <- dbGetQuery(con, query)[[1]]
  }
  return(tables)
}

dropAllTablesFromSchema <- function(connectionDetails, schema) {
  stopifnot(
    "ConnectionDetails" %in% class(connectionDetails),
    class(schema) == "character",
    length(schema) == 1
  )
  stopifnot(connectionDetails$dbms %in% c("postgresql", "redshift", "sql server", "oracle"))
  tableNames <- listTablesInSchema(connectionDetails, schema)

  con <- DatabaseConnector::connect(connectionDetails)
  on.exit(DatabaseConnector::disconnect(con))
  dbms <- connectionDetails$dbms
  if (dbms %in% c("redshift", "postgresql", "sql server")) {
    for (tableName in tableNames) {
      DBI::dbExecute(con, paste(
        "DROP TABLE IF EXISTS",
        paste(schema, tableName, sep = "."),
        "CASCADE"
      ))
    }
  } else if (dbms == "oracle") {
    for (tableName in tableNames) {
      DBI::dbExecute(con, paste("DROP TABLE IF EXISTS", tableName, "CASCADE"))
    }
  }
}