import datetime

from coldcall_lti import models, reports

D1 = datetime.date(2026, 10, 1)
D2 = datetime.date(2026, 10, 3)


def setup_course(db):
    course = models.Course(lti_context_id="ctx-1")
    db.add(course)
    db.flush()
    models.ensure_default_levels(db, course)
    students = []
    for i in range(3):
        s = models.Student(canvas_user_id=f"u{i}", name=f"Student {i}")
        db.add(s)
        students.append(s)
    db.flush()
    for s in students:
        db.add(models.Enrollment(course_id=course.id, student_id=s.id))
    db.flush()
    return course, students


def add_call(db, course, student, day, status, assessment=None):
    level_ids = {
        lvl.label: lvl.id
        for lvl in models.assessment_levels(db, course.id)
    }
    db.add(
        models.Call(
            course_id=course.id,
            student_id=student.id,
            session_date=day,
            status=status,
            assessment_id=level_ids[assessment] if assessment else None,
        )
    )
    db.flush()


def test_student_stats_fairness_denominator(db_session):
    course, (a, b, c) = setup_course(db_session)
    # Day 1: three questions; day 2: one question. b opted out day 1.
    add_call(db_session, course, a, D1, models.STATUS_ANSWERED, "GOOD")
    add_call(db_session, course, a, D1, models.STATUS_ANSWERED, "POOR")
    add_call(db_session, course, c, D1, models.STATUS_MISSING)
    add_call(db_session, course, b, D2, models.STATUS_ANSWERED, "GOOD")
    # Skipped and pending calls count nowhere.
    add_call(db_session, course, c, D2, models.STATUS_SKIPPED)
    add_call(db_session, course, c, D2, models.STATUS_PENDING)
    db_session.add(
        models.OptOut(course_id=course.id, student_id=b.id, date=D1)
    )
    db_session.flush()

    rows = {r["student"].id: r for r in reports.student_stats(db_session, course)}

    assert rows[a.id]["answered"] == 2
    assert rows[a.id]["questions_present"] == 4
    assert rows[a.id]["prop_asked"] == 0.5

    # b missed day 1's three questions by opting out.
    assert rows[b.id]["questions_present"] == 1
    assert rows[b.id]["prop_asked"] == 1.0
    assert rows[b.id]["optouts"] == 1

    assert rows[c.id]["answered"] == 0
    assert rows[c.id]["missing"] == 1
    assert rows[c.id]["prop_asked"] == 0.0


def test_assessments_by_day(db_session):
    course, (a, b, c) = setup_course(db_session)
    add_call(db_session, course, a, D1, models.STATUS_ANSWERED, "GOOD")
    add_call(db_session, course, b, D1, models.STATUS_ANSWERED, "GOOD")
    add_call(db_session, course, c, D1, models.STATUS_MISSING)
    add_call(db_session, course, a, D2, models.STATUS_ANSWERED, "SATISFACTORY")

    by_day = reports.assessments_by_day(db_session, course.id)
    assert [d["day"] for d in by_day] == [D1, D2]
    assert by_day[0]["counts"] == {"GOOD": 2, "missing": 1}
    assert by_day[0]["total"] == 3
    assert by_day[1]["counts"] == {"SATISFACTORY": 1}


def test_histogram_includes_zero_bin():
    h = reports.histogram([0, 0, 2])
    assert h["bins"] == [
        {"value": 0, "students": 2},
        {"value": 1, "students": 0},
        {"value": 2, "students": 1},
    ]
    assert h["max_students"] == 2