from datetime import date

import pytest

from app.core.dto.training import ApproachDTO, ExerciseSessionDTO
from app.core.metrics import estimate_1rm, session_metrics, summarize


def make_session(day: int, *sets: tuple, month: int = 1) -> ExerciseSessionDTO:
    return ExerciseSessionDTO(
        date=date(2025, month, day),
        approaches=[ApproachDTO(weight=weight, reps=reps) for weight, reps in sets],
    )


def test_estimate_1rm_uses_epley_formula():
    assert estimate_1rm(140, 12) == pytest.approx(196)
    assert estimate_1rm(100, 10) == pytest.approx(133.333, rel=1e-4)


def test_single_rep_is_the_weight_itself():
    assert estimate_1rm(100, 1) == 100


def test_session_metrics_of_weighted_sets():
    metrics = session_metrics(make_session(1, (100, 12), (110, 10)).approaches)

    assert metrics.max_weight == 110
    assert metrics.e1rm == pytest.approx(max(140.0, 110 * (1 + 10 / 30)))
    assert metrics.volume == 100 * 12 + 110 * 10
    assert metrics.total_reps == 22
    assert metrics.best_reps == 12


def test_sets_without_weight_count_only_as_reps():
    metrics = session_metrics(make_session(1, (0, 7), (47, 12)).approaches)

    assert metrics.e1rm == pytest.approx(estimate_1rm(47, 12))
    assert metrics.volume == 47 * 12
    assert metrics.total_reps == 19


def test_session_without_weight_has_no_e1rm():
    metrics = session_metrics(make_session(1, (0, 11), (0, 8)).approaches)

    assert metrics.e1rm is None
    assert metrics.volume == 0
    assert metrics.total_reps == 19
    assert metrics.best_reps == 11


def test_weighted_progress_records_and_change():
    # newest first, like the repository returns
    history = [
        make_session(20, (100, 12)),  # e1RM 140
        make_session(10, (110, 12), (100, 12)),  # e1RM 154 (record)
        make_session(1, (80, 10)),  # e1RM 106.67
    ]

    progress = summarize(history)

    assert progress.weighted is True
    assert progress.max_weight == 110
    assert progress.best_primary.value == pytest.approx(154)
    assert progress.best_primary.date == date(2025, 1, 10)
    assert progress.best_secondary.value == 110 * 12 + 100 * 12
    assert progress.first_primary == pytest.approx(80 * (1 + 10 / 30))
    assert progress.last_primary == pytest.approx(140)
    assert progress.primary_change == pytest.approx(140 - 80 * (1 + 10 / 30))
    assert progress.primary_change_percent == pytest.approx(
        (140 - 80 * (1 + 10 / 30)) / (80 * (1 + 10 / 30)) * 100
    )


def test_record_keeps_the_first_date_it_was_reached():
    history = [make_session(20, (100, 12)), make_session(10, (100, 12))]

    assert summarize(history).best_primary.date == date(2025, 1, 10)


def test_exercise_without_weight_is_tracked_by_reps():
    history = [
        make_session(20, (0, 8), (0, 7)),  # best 8, total 15
        make_session(10, (0, 10), (0, 5)),  # best 10, total 15
        make_session(1, (0, 6)),  # best 6, total 6
    ]

    progress = summarize(history)

    assert progress.weighted is False
    assert progress.max_weight == 0
    assert progress.best_primary.value == 10
    assert progress.best_primary.date == date(2025, 1, 10)
    assert progress.best_secondary.value == 15
    assert progress.best_secondary.date == date(2025, 1, 10)
    assert (progress.first_primary, progress.last_primary) == (6, 8)
    assert progress.primary_change == 2


def test_weighted_exercise_ignores_sessions_without_weight_for_primary_metric():
    history = [
        make_session(20, (0, 12)),  # no e1RM
        make_session(10, (100, 10)),
    ]

    progress = summarize(history)

    assert progress.weighted is True
    assert progress.last_primary == pytest.approx(estimate_1rm(100, 10))
    assert progress.primary_change == 0


def test_percent_change_is_undefined_when_the_first_value_is_zero():
    progress = summarize([make_session(1, (0, 0))])

    assert progress.primary_change_percent is None