import std/[times, unittest]

import fiber_orm/util

proc utcDateTime(nanosecond: NanosecondRange): DateTime =
  dateTime(
    2026, mAug, 26, 14, 32, 10, nanosecond,
    utc())

suite "PostgreSQL DateTime conversion":
  test "formats DateTime values with microsecond precision":
    check dbFormat(utcDateTime(123_457_000)) ==
      "2026-08-26T14:32:10.123457Z"

  test "parses whole-second, millisecond, and microsecond values":
    let cases = [
      ("2026-08-26 14:32:10+00", 0),
      ("2026-08-26 14:32:10.123+00", 123_000_000),
      ("2026-08-26 14:32:10.9007+00", 900_700_000),
      ("2026-08-26 14:32:10.12345+00", 123_450_000),
      ("2026-08-26 14:32:10.123457+00", 123_457_000),
    ]

    for (value, expectedNanosecond) in cases:
      let parsed = parsePGDatetime(value)
      check parsed.nanosecond == expectedNanosecond
      check parsed.utc.format("yyyy-MM-dd'T'HH:mm:ss") ==
        "2026-08-26T14:32:10"

  test "preserves supported separators and timezone representations":
    let timezoneCases = [
      "2026-08-26 14:32:10+00",
      "2026-08-26T14:32:10+00",
      "2026-08-26T14:32:10+00:00",
      "2026-08-26 14:32:10.123+00",
      "2026-08-26T14:32:10.123457+00:00",
      "2026-08-26T14:32:10.123457Z",
    ]

    for value in timezoneCases:
      check parsePGDatetime(value).utc.format("yyyy-MM-dd'T'HH:mm:ss") ==
        "2026-08-26T14:32:10"

    let localCases = [
      "2026-08-26 14:32:10",
      "2026-08-26T14:32:10",
      "2026-08-26 14:32:10.1",
      "2026-08-26T14:32:10.12",
    ]

    for value in localCases:
      check parsePGDatetime(value).format("yyyy-MM-dd'T'HH:mm:ss") ==
        "2026-08-26T14:32:10"