"""Phase 6.b integration tests — DATETIME decoding for all qualifier ranges.

DATETIME is BCD-packed with a qualifier embedded in encoded_length:
``(digit_count << 8) | (start_TU << 4) | end_TU`` where TU codes are
YEAR=0, MONTH=2, DAY=4, HOUR=6, MIN=8, SEC=10, FRAC1=11..FRAC5=15.

The decoder picks the appropriate Python type:
  - datetime.date for qualifiers ending at YEAR/MONTH/DAY
  - datetime.time for qualifiers starting at HOUR or later
  - datetime.datetime for spans crossing the date/time boundary
"""

from __future__ import annotations

import datetime

import pytest

import informix_db
from tests.conftest import ConnParams

pytestmark = pytest.mark.integration


def _connect(conn_params: ConnParams) -> informix_db.Connection:
    return informix_db.connect(
        host=conn_params.host,
        port=conn_params.port,
        user=conn_params.user,
        password=conn_params.password,
        database=conn_params.database,
        server=conn_params.server,
        connect_timeout=10.0,
        read_timeout=10.0,
    )


def test_datetime_year_to_second(conn_params: ConnParams) -> None:
    """Full date+time → datetime.datetime."""
    with _connect(conn_params) as conn:
        cur = conn.cursor()
        cur.execute(
            "SELECT DATETIME(2026-05-04 12:34:56) YEAR TO SECOND "
            "FROM systables WHERE tabid = 1"
        )
        assert cur.fetchone() == (datetime.datetime(2026, 5, 4, 12, 34, 56),)


def test_datetime_year_to_day(conn_params: ConnParams) -> None:
    """Date-only qualifier → datetime.date."""
    with _connect(conn_params) as conn:
        cur = conn.cursor()
        cur.execute(
            "SELECT DATETIME(2026-05-04) YEAR TO DAY "
            "FROM systables WHERE tabid = 1"
        )
        assert cur.fetchone() == (datetime.date(2026, 5, 4),)


def test_datetime_hour_to_second(conn_params: ConnParams) -> None:
    """Time-only qualifier → datetime.time."""
    with _connect(conn_params) as conn:
        cur = conn.cursor()
        cur.execute(
            "SELECT DATETIME(12:34:56) HOUR TO SECOND "
            "FROM systables WHERE tabid = 1"
        )
        assert cur.fetchone() == (datetime.time(12, 34, 56),)


def test_datetime_current_with_fraction(conn_params: ConnParams) -> None:
    """CURRENT YEAR TO FRACTION returns a datetime.datetime."""
    with _connect(conn_params) as conn:
        cur = conn.cursor()
        cur.execute(
            "SELECT CURRENT YEAR TO FRACTION(3) FROM systables WHERE tabid = 1"
        )
        (val,) = cur.fetchone()
        assert isinstance(val, datetime.datetime)
        # Sanity: should be within a reasonable timeframe of "now"
        now = datetime.datetime.now()
        assert abs((val - now).total_seconds()) < 86400  # within a day


def test_datetime_multiple_columns_in_one_row(conn_params: ConnParams) -> None:
    """Multiple DATETIME qualifiers in one row — proves per-column slicing."""
    with _connect(conn_params) as conn:
        cur = conn.cursor()
        cur.execute(
            "SELECT "
            "  DATETIME(2026-05-04 12:34:56) YEAR TO SECOND, "
            "  DATETIME(2026-05-04) YEAR TO DAY, "
            "  DATETIME(12:34:56) HOUR TO SECOND "
            "FROM systables WHERE tabid = 1"
        )
        ts, d, t = cur.fetchone()
        assert ts == datetime.datetime(2026, 5, 4, 12, 34, 56)
        assert d == datetime.date(2026, 5, 4)
        assert t == datetime.time(12, 34, 56)


def test_datetime_column_in_table(conn_params: ConnParams) -> None:
    """DATETIME stored in a table column round-trips correctly."""
    with _connect(conn_params) as conn:
        cur = conn.cursor()
        cur.execute(
            "CREATE TEMP TABLE t_dt (id INTEGER, ts DATETIME YEAR TO SECOND)"
        )
        cur.execute(
            "INSERT INTO t_dt VALUES (1, DATETIME(2026-01-15 09:30:00) YEAR TO SECOND)"
        )
        cur.execute("SELECT ts FROM t_dt")
        assert cur.fetchone() == (datetime.datetime(2026, 1, 15, 9, 30, 0),)


def test_datetime_null(conn_params: ConnParams) -> None:
    """NULL DATETIME decodes to Python None."""
    with _connect(conn_params) as conn:
        cur = conn.cursor()
        cur.execute("CREATE TEMP TABLE t_dt2 (ts DATETIME YEAR TO SECOND)")
        cur.execute("INSERT INTO t_dt2 VALUES (NULL)")
        cur.execute("SELECT ts FROM t_dt2")
        assert cur.fetchone() == (None,)