## A Snowflake database is required for these tests.
## You can get a free trial at https://signup.snowflake.com/
## The server is given by the account identifier ex: WYKESWE-XF50993.snowflakecomputing.com
## Make sure to create a database EXAMPLE

snowflake_is_working <-
  tryCatch({
    con <-
      DBI::dbConnect(
        odbc::odbc(),
        dsn = "Snowflake_Trial",
        pwd = keyring::key_get("SnowflakeTrialPassword")
      )
    TRUE
  }, error = function(error){
    FALSE
  })

if (snowflake_is_working){

  test_that(
    "get_schemas retrieves schemas correctly",
    {

      expect_equal(
        get_schemas_snowflake(con),
        c("INFORMATION_SCHEMA", "PUBLIC")
      )

    }
  )

  test_that(
    "get_tables retrieves tables correctly",
    {

      mtcars_2 <- mtcars

      rownames(mtcars_2) <-
        seq_len(nrow(mtcars))

      DBI::dbWriteTable(
        con,
        name = DBI::Id(
          schema = "PUBLIC",
          table = "MTCARS"
        ),
        value = mtcars_2,
        overwrite = TRUE,
        row.names = TRUE
      )

      expect_true(
        "MTCARS" %in% get_tables_snowflake(
          con,
          schema = "PUBLIC"
        )
      )

    }
  )

  test_that(
    "get_n_rows retrieves the correct number of rows of a table",
    {
      expect_equal(
        get_n_rows_snowflake(
          con,
          schema = "PUBLIC",
          table = "MTCARS"
        ) |> as.numeric(),
        nrow(mtcars) |> as.numeric()
      )
    }
  )

  test_that(
    "get_n_rows retrieves the correct number of rows of a query",
    {
      expect_equal(
        get_n_rows_snowflake(
          con,
          schema = "PUBLIC",
          table = "MTCARS",
          query = "SELECT * FROM MTCARS LIMIT 10"
        ) |> as.numeric(),
        10
      )
    }
  )

  test_that(
    "get_preview returns a view of the dataframe",
    {

      # Note: Snowflake writes tables in a different order

      mtcars_2 <- mtcars

      rownames(mtcars_2) <-
        seq_len(nrow(mtcars))

      expect_equal(
        get_preview_snowflake(
          con,
          schema = "PUBLIC",
          table = "MTCARS"
        ) |>
          dplyr::mutate(
            row_names = readr::parse_number(
              row_names
            )
          ) |>
          dplyr::arrange(row_names) |>
          dplyr::select(-c("row_names")),
        mtcars_2
      )
    }
  )

  test_that(
    "a create table query works correcty",
    {
      n_rows = get_n_rows_snowflake(
        con = con,
        schema = "",
        table = "",
        "CREATE TABLE mtcars_2 AS SELECT * FROM mtcars"
      )

      submit_query(
        "USE SCHEMA PUBLIC",
        con = con,
        n_rows = n_rows
      )

      submit_query(
        "CREATE TABLE mtcars_2 AS SELECT * FROM mtcars",
        con = con,
        n_rows = n_rows
      )

      expect_true(
        "MTCARS_2" %in% DBI::dbListTables(con)
      )
    }
  )

  test_that(
    "delete_table correctly drops the table",
    {
      expect_true(
        "MTCARS" %in% DBI::dbListTables(con)
      )

      expect_equal(
        "Success",
        delete_table_snowflake(
          con,
          schema = "PUBLIC",
          table = "MTCARS"
        )
      )

      expect_equal(
        "Success",
        delete_table_snowflake(
          con,
          schema = "PUBLIC",
          table = "MTCARS_2"
        )
      )

      expect_false(
        "MTCARS" %in% DBI::dbListTables(con)
      )

      expect_false(
        "MTCARS_2" %in% DBI::dbListTables(con)
      )

    }
  )

  test_that(
    "write_table correctly uploads table",
    {

      DBI::dbSendQuery(con, "CREATE SCHEMA EXAMPLE") |>
        DBI::dbClearResult()

      DBI::dbSendQuery(con, "USE SCHEMA EXAMPLE") |>
        DBI::dbClearResult()

      write_table_snowflake(
        con,
        schema = "EXAMPLE",
        table_name = "MTCARS",
        data = mtcars
      )

      expect_true(
        "MTCARS" %in% get_tables_snowflake(con, schema = "EXAMPLE")
      )

      DBI::dbSendQuery(con, "DROP SCHEMA EXAMPLE") |>
        DBI::dbClearResult()

    }
  )

  test_that(
    "a join query returns the correct number of rows",
    {
      table_1 <-
        data.frame(
          x = c(1, 2, 3),
          y = c("A", "B", "C")
        )

      table_2 <-
        data.frame(
          z = c(4, 5, 6),
          y = c("A", "B", "C")
        )

      DBI::dbWriteTable(
        con,
        name = DBI::Id(
          schema = "PUBLIC",
          table = "TABLE_1"
        ),
        value = table_1,
        overwrite = TRUE,
        row.names = TRUE
      )

      DBI::dbWriteTable(
        con,
        name = DBI::Id(
          schema = "PUBLIC",
          table = "TABLE_2"
        ),
        value = table_2,
        overwrite = TRUE,
        row.names = TRUE
      )

      expect_equal(
        get_n_rows_snowflake(
          con = con,
          schema = "",
          table = "",
          query = "SELECT * FROM TABLE_1 INNER JOIN TABLE_2 USING(\"y\")"
        ) |> as.numeric(),
        3
      )
    }
  )

  test_that(
    "a cte query returns the correct number of rows",
    {
      DBI::dbWriteTable(
        con,
        "MTCARS",
        mtcars,
        overwrite = TRUE
      )

      n_rows <- get_n_rows_snowflake(
        con = con,
        schema = "",
        table = "",
        query = "WITH cte1 AS (SELECT * FROM MTCARS) SELECT * FROM cte1"
      )

      expect_equal(
        n_rows,
        nrow(mtcars)
      )
    }
  )

  DBI::dbDisconnect(con)
}