# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

context(paste(Sys.getenv("PRESTO_TYPE", "Presto"), "session.timezone"))

test_that("session.timezone works", {
  # We suppress warnings because R now uses timedatectl for timezone
  # inference on systemd systems which can give an 'access denied' warning
  current.timezone <- suppressWarnings(Sys.timezone())
  if (!is.na(current.timezone)) {
    on.exit(Sys.setenv(TZ = current.timezone))
  } else {
    on.exit(Sys.unsetenv("TZ"))
  }

  Sys.setenv(TZ = "Asia/Tokyo")

  conn <- setup_live_connection(session.timezone = "Europe/Istanbul")
  expect_equal(conn@session.timezone, "Europe/Istanbul")

  # At 2014-10-26 04:00:00 Istanbul switched back to Standard time from
  # daylight saving. Tokyo did not observe daylight saving in 2014.
  timestamp_6am <- "2014-10-26 06:00:00"
  timestamp_1pm <- "2014-10-26 13:00:00"
  timestamp_0am <- "2014-10-26 00:00:00"
  timestamp_1am <- "2014-10-26 01:00:00"
  timestamp_8pm <- "2014-10-26 20:00:00"
  tokyo_1pm <- as.POSIXct(timestamp_1pm)
  tokyo_1pm_timestamp <- as.character(tokyo_1pm) # 2014-10-26 13:00:00
  tokyo_1pm_unixtime <- as.numeric(tokyo_1pm)

  tokyo_6am <- as.POSIXct(timestamp_6am)
  tokyo_6am_timestamp <- as.character(tokyo_6am)

  tokyo_8pm <- as.POSIXct(timestamp_8pm)
  tokyo_8pm_timestamp <- as.character(tokyo_8pm)

  istanbul_1pm <- as.POSIXct(timestamp_1pm, tz = "Europe/Istanbul")
  istanbul_1pm_timestamp <- as.character(istanbul_1pm)
  istanbul_1pm_unixtime <- as.numeric(istanbul_1pm)

  istanbul_6am <- as.POSIXct(timestamp_6am, tz = "Europe/Istanbul")
  istanbul_6am_timestamp <- as.character(istanbul_6am)
  istanbul_6am_unixtime <- as.numeric(istanbul_6am)

  istanbul_1am <- as.POSIXct(timestamp_1am, tz = "Europe/Istanbul")
  istanbul_0am <- as.POSIXct(timestamp_0am, tz = "Europe/Istanbul")

  expect_equal(tokyo_1pm_timestamp, istanbul_1pm_timestamp)
  expect_equal(istanbul_1pm_unixtime - tokyo_1pm_unixtime, 7 * 60 * 60)

  expect_equal(tokyo_1pm_unixtime, istanbul_6am_unixtime)

  rv <- dbGetQuery(
    conn,
    sprintf(
      "SELECT
      -- Should have Istanbul timezone
      FROM_UNIXTIME(%f) AS \"from_unixtime\",
      TO_UNIXTIME(TIMESTAMP '%s') AS \"to_unixtime\",
      ABS(%f - TO_UNIXTIME(TIMESTAMP '%s')) < 1 AS \"unixtime_same\",
      TIMESTAMP '%s' AS \"timestamp\",
      TIMESTAMP '%s' - INTERVAL '13' HOUR AS \"dst_timestamp\",
      -- Without proper time zone parsing in R, this will return true
      -- since the string returned by presto will be parsed in Tokyo timezone
      TIMESTAMP '%s' < FROM_UNIXTIME(%f) AS \"tokyo_vs_istanbul\",
      DATE_FORMAT(
        -- Note that timestamp is first parsed in session timezone, then
        -- changed to the given time zone
        TIMESTAMP '%s' AT TIME ZONE 'Asia/Tokyo',
        '%%Y-%%m-%%d %%H:%%i:%%s'
      ) AS \"date_format\",
      DATE_FORMAT(
        TIMESTAMP '2014-10-26 00:00:00' AT TIME ZONE 'Asia/Tokyo',
        '%%Y-%%m-%%d %%H:%%i:%%s'
      ) AS \"date_format_before_standard_time\"",
      tokyo_1pm_unixtime,
      timestamp_1pm,
      tokyo_1pm_unixtime, timestamp_1pm,
      timestamp_1pm,
      timestamp_1pm,
      timestamp_1pm, tokyo_1pm_unixtime + 1,
      timestamp_1pm
    )
  )
  ev <- tibble::tibble(
    from_unixtime = istanbul_6am,
    to_unixtime = istanbul_1pm_unixtime,
    unixtime_same = FALSE, # tokyo_1pm_unixtime vs istanbul_1pm_unixtime
    timestamp = istanbul_1pm,
    dst_timestamp = as.POSIXct(ifelse(conn@use.trino.headers, istanbul_0am, istanbul_1am), tz = "Europe/Istanbul"), # Presto respects DST while Trino doesn't
    tokyo_vs_istanbul = FALSE,
    date_format = tokyo_8pm_timestamp,
    date_format_before_standard_time = tokyo_6am_timestamp
  )
  expect_equal_data_frame(rv, ev)
})