test_that("precision methods", {
    dts <- as_datetimeoffset(c("", "2020", "2020-04-10", "2020-04-10T10:10"))
    expect_equal(datetime_precision(datetimeoffset()), character())
    expect_equal(datetime_precision(dts),
                 c("missing", "year", "day", "minute"))
    expect_equal(datetime_precision(dts, range = TRUE),
                 c("missing", "minute"))

    dtn <- datetime_narrow(dts, "day")
    expect_equal(format(dtn), c(NA_character_, "2020", "2020-04-10", "2020-04-10"))

    dtc <- datetime_cast(dts, "day")
    expect_equal(format(dtc), c(NA_character_, "2020-01-01", "2020-04-10", "2020-04-10"))

    dtn <- datetime_narrow(dts, "year")
    expect_equal(format(dtn), c(NA_character_, "2020", "2020", "2020"))

    dtc <- datetime_cast(dts, "year")
    expect_equal(format(dtc), c(NA_character_, "2020", "2020", "2020"))

    dtc <- datetime_cast(NA_datetimeoffset_, "day", month = 6L, na_set = TRUE)
    expect_equal(format(dtc), "0000-06-01")
    dtc <- datetime_cast(NA_datetimeoffset_, "day", month = 6L)
    expect_equal(format(dtc), NA_character_)

    ymd <- clock::as_year_month_day(as_datetimeoffset("2020-04-10"))
    expect_equal(format(datetime_narrow(ymd, "year")), "2020")
    expect_equal(format(datetime_widen(ymd, "hour")), "2020-04-10T00")

    dtw <- datetime_widen(dts, "day")
    expect_equal(format(dtw), c(NA_character_, "2020-01-01", "2020-04-10", "2020-04-10T10:10"))
    dtw <- datetime_widen(dts, "day", na_set = TRUE)
    expect_equal(format(dtw), c("0000-01-01", "2020-01-01", "2020-04-10", "2020-04-10T10:10"))

    # vectorize precision
    dt <- as_datetimeoffset("2020-04-10T10:10:10.123456789")
    expect_equal(format(datetime_narrow(dt, c("missing", "year", "month", "day"))),
                 c(NA_character_, "2020", "2020-04", "2020-04-10"))
    dt <- as_datetimeoffset("2020-04-10")
    expect_equal(format(datetime_cast(dt, c("missing", "year", "day", "minute"))),
                 c(NA_character_, "2020", "2020-04-10", "2020-04-10T00:00"))

    dt <- NA_datetimeoffset_
    expect_equal(format(datetime_widen(dt, c("missing", "year", "month", "day"), na_set = TRUE)),
                 c(NA_character_, "0000", "0000-01", "0000-01-01"))

    # EDTF precisions
    dt <- as_datetimeoffset("2020-XX-04")
    expect_equal(datetime_precision(dt), "year")
    expect_equal(datetime_precision(dt, unspecified = TRUE), "day")
    expect_equal(format(datetime_narrow(dt, "missing")), NA_character_)
})

test_that("precision methods for {clock}", {

    dt <- as.POSIXct("1918-11-11 11:11:11", tz = "GMT")
    expect_equal(datetime_widen(dt, "day"), dt)
    expect_equal(format(datetime_narrow(dt, "day")), "1918-11-11")
    expect_equal(format(datetime_narrow(dt, "day", method = "ceiling")), "1918-11-12")
    expect_equal(format(datetime_narrow(dt, "day", method = "round")), "1918-11-11")
    expect_equal(format(datetime_cast(dt, "day")), "1918-11-11")

    expect_equal(datetime_precision(clock::year_month_day(1918, 11, 11)), "day")
    expect_equal(datetime_precision(clock::sys_time_now()), "nanosecond")
    expect_equal(datetime_precision(clock::zoned_time_now(Sys.timezone())), "nanosecond")

    ymd <- clock::year_month_day(1918, 11, 11, 11, 11)
    expect_equal(format(datetime_narrow(ymd, "month")), "1918-11")
    expect_equal(format(datetime_narrow(ymd, "second")), "1918-11-11T11:11")
    expect_equal(format(datetime_widen(ymd, "second")), "1918-11-11T11:11:00")
    expect_equal(format(datetime_widen(ymd, "month")), "1918-11-11T11:11")

    nt <- clock::as_naive_time(ymd)
    expect_equal(format(datetime_narrow(nt, "day")), "1918-11-11")
    expect_equal(format(datetime_cast(nt, "day")), "1918-11-11")
    expect_equal(format(datetime_narrow(nt, "hour")), "1918-11-11T11")
    expect_equal(format(datetime_narrow(nt, "hour", method = "ceiling")), "1918-11-11T12")
    expect_equal(format(datetime_narrow(nt, "hour", method = "round")), "1918-11-11T11")
    expect_equal(format(datetime_narrow(nt, "hour", method = "cast")), "1918-11-11T12")
    expect_equal(format(datetime_cast(nt, "hour", method = "cast")), "1918-11-11T12")
    expect_equal(format(datetime_narrow(nt, "second")), "1918-11-11T11:11")
    expect_equal(format(datetime_widen(nt, "second")), "1918-11-11T11:11:00")
    expect_equal(format(datetime_cast(nt, "second")), "1918-11-11T11:11:00")
    expect_equal(format(datetime_widen(nt, "month")), "1918-11-11T11:11")
})

test_that("precision methods for {nanotime}", {
    skip_if_not_installed("nanotime")
    expect_equal(datetime_precision(as.nanotime(Sys.time())), "nanosecond")
})