"""
Tester for TeeCup handicap-motor.

Fasitverdiene er hentet fra R&A Rules of Handicapping, Appendix C, der det er
mulig, slik at motoren kan verifiseres mot en autoritativ kilde uavhengig av
resten av systemet (ADR-005).

Kjør:  python -m pytest test_handicap_engine.py -v
   ev.  python test_handicap_engine.py   (kjører en enkel selvsjekk uten pytest)
"""

from datetime import date

from handicap_engine import (
    Format,
    HoleResult,
    Player,
    PerPlayerPercentage,
    CombinedPercentage,
    WeightedLowHigh,
    RankedSplit,
    DEFAULT_MATCHPLAY_ALLOWANCES,
    adjusted_gross_score,
    allocate_strokes_by_index,
    allocate_over_played_holes,
    apply_index_caps,
    compute_match_state,
    course_handicap,
    course_handicap_9,
    course_handicap_9_raw,
    course_handicap_raw,
    handicap_index_from_differentials,
    low_handicap_index,
    match_play_strokes,
    max_hole_score_for_handicap,
    net_par,
    round_half_up,
    round_half_up_decimal,
    score_differential,
    unit_playing_handicap,
)


# ---------------------------------------------------------------------------
# Avrunding
# ---------------------------------------------------------------------------

def test_round_half_up_positive():
    assert round_half_up(16.2) == 16
    assert round_half_up(15.3) == 15
    assert round_half_up(26.1) == 26
    assert round_half_up(0.5) == 1        # 0,5 alltid opp (ikke banker's)
    assert round_half_up(2.5) == 3
    assert round_half_up(1.5) == 2


def test_round_half_up_negative():
    # Minus-handicap (plusspillere)
    assert round_half_up(-2.5) == -2
    assert round_half_up(-0.5) == 0


# ---------------------------------------------------------------------------
# Course Handicap
# ---------------------------------------------------------------------------

def test_course_handicap_formula():
    # Index 18.0, Slope 113 (nøytral), CR == Par -> nøyaktig 18
    assert course_handicap_raw(18.0, 113, 72.0, 72) == 18.0
    # Slope 130, CR 71.5, Par 72
    raw = course_handicap_raw(10.0, 130, 71.5, 72)
    assert abs(raw - (10.0 * 130 / 113 + (71.5 - 72))) < 1e-9
    assert course_handicap(10.0, 130, 71.5, 72) == round_half_up(raw)


# ---------------------------------------------------------------------------
# Singles match play (R&A Appendix C, Eksempel 2): 100 %
#   A spiller av 0, B mottar 8 slag.
# ---------------------------------------------------------------------------

def test_singles_match_play_appendix_c_example_2():
    strat = DEFAULT_MATCHPLAY_ALLOWANCES[Format.SINGLES]
    # To spillere med course handicap som skiller 8 (100 % allowance)
    a = Player("A", 8.0, 113, 72.0, 72)   # CH 8
    b = Player("B", 16.0, 113, 72.0, 72)  # CH 16
    ph_a = unit_playing_handicap([a], strat)
    ph_b = unit_playing_handicap([b], strat)
    strokes = match_play_strokes([ph_a, ph_b])
    assert strokes == [0, 8]


# ---------------------------------------------------------------------------
# Four-ball match play (R&A Appendix C, Eksempel 3): 90 % per spiller
#   Course handicaps 10 / 18 / 27 / 39  ->  0 / 7 / 15 / 26
# ---------------------------------------------------------------------------

def test_fourball_match_play_appendix_c_example_3():
    strat = DEFAULT_MATCHPLAY_ALLOWANCES[Format.FOURBALL]
    chs = [10, 18, 27, 39]
    players = [Player(f"P{i}", ch, 113, 72.0, 72) for i, ch in enumerate(chs)]
    phs = [unit_playing_handicap([p], strat) for p in players]
    # 90 % avrundet: 9, 16, 24, 35
    assert phs == [9, 16, 24, 35]
    strokes = match_play_strokes(phs)
    assert strokes == [0, 7, 15, 26]


# ---------------------------------------------------------------------------
# Foursomes match play (R&A Appendix C, Eksempel 4): 50 % av differansen
#   mellom lagenes samlede course handicap. Team 2 mottar 19.
#   -> lagenes samlede CH skiller 38.
# ---------------------------------------------------------------------------

def test_foursome_match_play_appendix_c_example_4():
    strat = DEFAULT_MATCHPLAY_ALLOWANCES[Format.FOURSOME]
    # Team 1 samlet CH = 20, Team 2 samlet CH = 58 -> differanse 38
    team1 = [Player("A", 8.0, 113, 72.0, 72), Player("B", 12.0, 113, 72.0, 72)]   # sum 20
    team2 = [Player("C", 28.0, 113, 72.0, 72), Player("D", 30.0, 113, 72.0, 72)]  # sum 58
    ph1 = unit_playing_handicap(team1, strat)  # 50 % av 20 = 10
    ph2 = unit_playing_handicap(team2, strat)  # 50 % av 58 = 29
    assert ph1 == 10 and ph2 == 29
    strokes = match_play_strokes([ph1, ph2])
    assert strokes == [0, 19]


# ---------------------------------------------------------------------------
# Greensomes: 60 % laveste + 40 % høyeste
# ---------------------------------------------------------------------------

def test_greensome_weighted_allowance():
    strat = WeightedLowHigh(0.60, 0.40)
    # CH 12 og 20 -> 0,6*12 + 0,4*20 = 7,2 + 8,0 = 15,2 -> 15
    p_low = Player("L", 12.0, 113, 72.0, 72)
    p_high = Player("H", 20.0, 113, 72.0, 72)
    assert unit_playing_handicap([p_low, p_high], strat) == 15
    # rekkefølge skal ikke spille noen rolle
    assert unit_playing_handicap([p_high, p_low], strat) == 15


# ---------------------------------------------------------------------------
# Scramble: rangert splitt
# ---------------------------------------------------------------------------

def test_scramble_4_ranked_split():
    strat = RankedSplit((0.25, 0.20, 0.15, 0.10))
    # CH 4, 10, 16, 24 -> 0,25*4 + 0,20*10 + 0,15*16 + 0,10*24
    #                   = 1,0 + 2,0 + 2,4 + 2,4 = 7,8 -> 8
    players = [Player(f"P{i}", ch, 113, 72.0, 72) for i, ch in enumerate([24, 4, 16, 10])]
    assert unit_playing_handicap(players, strat) == 8  # rekkefølge irrelevant


def test_scramble_2_ranked_split():
    strat = RankedSplit((0.35, 0.15))
    # CH 6 og 18 -> 0,35*6 + 0,15*18 = 2,1 + 2,7 = 4,8 -> 5
    players = [Player("A", 18.0, 113, 72.0, 72), Player("B", 6.0, 113, 72.0, 72)]
    assert unit_playing_handicap(players, strat) == 5


def test_allowance_is_configurable_not_hardcoded():
    """ADR-005: motoren skal godta en overstyrt allowance (f.eks. 75 %/3/4)."""
    strat_75 = PerPlayerPercentage(0.75)
    p = Player("X", 20.0, 113, 72.0, 72)  # CH 20
    assert unit_playing_handicap([p], strat_75) == 15  # 0,75*20


# ---------------------------------------------------------------------------
# Slagfordeling på Stroke Index
# ---------------------------------------------------------------------------

def test_allocate_strokes_basic():
    si = list(range(1, 19))  # SI 1..18
    # 5 slag -> ett slag på SI 1..5, null ellers
    alloc = allocate_strokes_by_index(5, si)
    assert sum(alloc) == 5
    assert alloc[0] == 1 and alloc[4] == 1 and alloc[5] == 0


def test_allocate_strokes_high_handicap_double():
    si = list(range(1, 19))
    # 20 slag -> alle hull minst 1, SI 1 og 2 får 2
    alloc = allocate_strokes_by_index(20, si)
    assert sum(alloc) == 20
    assert alloc[0] == 2 and alloc[1] == 2 and alloc[2] == 1


def test_allocate_strokes_zero():
    si = list(range(1, 19))
    assert allocate_strokes_by_index(0, si) == [0] * 18


def test_allocate_strokes_plus_handicap_gives_back():
    si = list(range(1, 19))
    # -2 slag: gir tilbake på de to letteste hullene (SI 18 og 17)
    alloc = allocate_strokes_by_index(-2, si)
    assert sum(alloc) == -2
    # SI 18 er indeks 17, SI 17 er indeks 16
    assert alloc[17] == -1 and alloc[16] == -1
    assert alloc[0] == 0


def test_allocate_strokes_respects_scorecard_order():
    # Hullenes SI i kortrekkefølge (ikke sortert): fordelingen skal følge SI-verdien
    si = [5, 1, 12, 3, 18, 7, 9, 11, 15, 2, 4, 6, 8, 10, 13, 14, 16, 17]
    alloc = allocate_strokes_by_index(3, si)
    assert sum(alloc) == 3
    # Slag skal ligge på hull med SI 1, 2, 3
    for hole_si, strokes in zip(si, alloc):
        assert strokes == (1 if hole_si <= 3 else 0)


# ---------------------------------------------------------------------------
# 9-hulls-fordeling (front/back) — "slagene faller på 18-hulls-kortet"
# ---------------------------------------------------------------------------

# Standard 18-hulls stroke index i hullrekkefølge: hull 1 har SI 1, hull 2 SI 3, ...
# Odde SI på front-9, par SI på back-9.
_FRONT_ODD_SI = [1, 3, 5, 7, 9, 11, 13, 15, 17]
_BACK_EVEN_SI = [2, 4, 6, 8, 10, 12, 14, 16, 18]
_ALL18_SI = _FRONT_ODD_SI + _BACK_EVEN_SI          # hull 1..18
_FRONT_HOLES = list(range(1, 10))                  # hull 1..9
_BACK_HOLES = list(range(10, 19))                  # hull 10..18


def test_nine_hole_three_strokes_back_vs_front():
    # 3 mottatte slag: faller på SI 1, 2, 3.
    back = allocate_over_played_holes(3, _ALL18_SI, _BACK_HOLES)
    front = allocate_over_played_holes(3, _ALL18_SI, _FRONT_HOLES)
    assert sum(back) == 1    # kun SI 2 på back-9
    assert sum(front) == 2   # SI 1 og 3 på front-9


def test_nine_hole_twelve_strokes_is_six_not_ten():
    # Kjernetesten: 12 slag på back-9 skal bli 6, ikke 10 (den naive feilen).
    back = allocate_over_played_holes(12, _ALL18_SI, _BACK_HOLES)
    assert sum(back) == 6
    # SI 2,4,6,8,10,12 får slag; SI 14,16,18 får ikke.
    assert back == [1, 1, 1, 1, 1, 1, 0, 0, 0]


def test_nine_hole_matches_naive_only_when_low():
    # Metodene sammenfaller så lenge totalen ikke overstiger antall spilte hull
    # (her 9): opp til 8 er base-slaget i den naive varianten fortsatt 0.
    for total in range(0, 9):
        correct = sum(allocate_over_played_holes(total, _ALL18_SI, _BACK_HOLES))
        naive = sum(allocate_strokes_by_index(total, _BACK_EVEN_SI))
        assert correct == naive
    # Fra og med 9 spriker de:
    assert sum(allocate_over_played_holes(12, _ALL18_SI, _BACK_HOLES)) \
        != sum(allocate_strokes_by_index(12, _BACK_EVEN_SI))


# ---------------------------------------------------------------------------
# Match-status
# ---------------------------------------------------------------------------

def test_match_state_all_square():
    results = [HoleResult.SIDE_A, HoleResult.SIDE_B, HoleResult.HALVED]
    state = compute_match_state(results, total_holes=18)
    assert state.lead == 0
    assert state.describe() == "AS"


def test_match_state_two_up():
    results = [HoleResult.SIDE_A, HoleResult.SIDE_A, HoleResult.HALVED]
    state = compute_match_state(results, total_holes=18)
    assert state.lead == 2
    assert state.describe() == "2 UP (A)"


def test_match_state_dormie():
    # A leder med 2, og det gjenstår nøyaktig 2 hull
    results = [HoleResult.SIDE_A] * 2 + [HoleResult.HALVED] * 14
    state = compute_match_state(results, total_holes=18)
    assert state.holes_remaining == 2
    assert state.is_dormie is True
    assert state.describe() == "dormie 2 (A)"


def test_match_state_closed_3_and_2():
    # A leder med 3 etter 16 hull -> 2 gjenstår -> avgjort "3&2"
    results = [HoleResult.SIDE_A] * 3 + [HoleResult.HALVED] * 13
    state = compute_match_state(results, total_holes=18)
    assert state.is_closed is True
    assert state.describe() == "3&2 (A)"


def test_match_state_won_on_last_hole():
    # A leder med 1 etter 18 hull -> vunnet "1 UP"
    results = [HoleResult.SIDE_A] + [HoleResult.HALVED] * 17
    state = compute_match_state(results, total_holes=18)
    assert state.holes_remaining == 0
    assert state.describe() == "1 UP (A)"


def test_match_state_side_b_leads():
    results = [HoleResult.SIDE_B, HoleResult.SIDE_B, HoleResult.SIDE_A]
    state = compute_match_state(results, total_holes=18)
    assert state.lead == -1
    assert state.describe() == "1 UP (B)"


# ---------------------------------------------------------------------------
# HCP-indeksberegning fra spilte runder (ADR-033)
#
# Fasitverdiene under er, der mulig, hentet direkte fra egne diagrammer og
# tallregneeksempler i "WHS Rules of Handicapping" (effektiv januar 2024,
# USGA/R&A) — samme prinsipp som resten av filen (ADR-005): verifiser mot en
# autoritativ kilde, ikke bare intern konsistens.
# ---------------------------------------------------------------------------

def test_round_half_up_decimal_rule_5_1c_examples():
    # Rule 5.1c sine tre eksplisitte eksempler, inkl. negative verdier.
    assert round_half_up_decimal(-1.54, 1) == -1.5
    assert round_half_up_decimal(-1.55, 1) == -1.5
    assert round_half_up_decimal(-1.56, 1) == -1.6
    assert round_half_up_decimal(15.25, 1) == 15.3


def test_net_par():
    # Net Par (Rule 3.2b/2) -- par + mottatte handicapslag.
    assert net_par(par=4, strokes_received=1) == 5
    assert net_par(par=4, strokes_received=0) == 4


def test_max_hole_score_for_handicap():
    # Net Double Bogey (Rule 3.1b): par + 2 + mottatte slag.
    assert max_hole_score_for_handicap(4, 1) == 7
    # Diagram 3.1b sitt eksempel: par 4, 1 mottatt slag -> maks 7.
    assert max_hole_score_for_handicap(par=4, strokes_received=1) == 7
    # Før indeks etablert (Rule 3.1a): par + 5, uavhengig av slag.
    assert max_hole_score_for_handicap(5, strokes_received=0, index_established=False) == 10


def test_adjusted_gross_score_diagram_3_1b_worked_example():
    # John Smith, HCP 16, Diagram 3.1b. Front-9 (par/SI/score) er lest
    # tydelig og eksakt fra diagrammet (Out = 35 par / 43 gross, begge
    # verifisert ved summering) -- brukt uendret her.
    #
    # Back-9: par/SI-radene er like eksakte (In = 35 par, verifisert), MEN
    # selve score-tallrekken i bilde-utsnittet er for utydelig til å stole
    # blindt på hver enkelt siffer -- summen min (46) stemte ikke med
    # diagrammets oppgitte "In 45". Eneste back-9-tallet jeg er HELT sikker
    # på (egen, tydelig uthevet boks i diagrammet, med piler): hull 17
    # (par 4, SI 6, mottar 1 slag ved HCP 16) hadde bruttoscore 9, capped
    # til Net Double Bogey 7. De ANDRE åtte back-9-scorene under er derfor
    # egenkomponerte (ikke hentet fra diagrammet) -- valgt lavt nok til at
    # ingen av dem selv trigger en cap, slik at testen isolert kan
    # verifisere nøyaktig den ene, kildebelagte capping-hendelsen.
    front9_pars = [4, 4, 3, 4, 5, 4, 3, 4, 4]
    front9_si = [7, 13, 3, 15, 11, 1, 17, 5, 9]
    front9_scores = [5, 5, 6, 4, 5, 5, 3, 5, 5]
    assert sum(front9_pars) == 35 and sum(front9_scores) == 43  # Out, begge fra diagrammet

    back9_pars = [3, 4, 5, 3, 4, 5, 3, 4, 4]
    back9_si = [18, 12, 4, 14, 8, 2, 16, 6, 10]
    assert sum(back9_pars) == 35  # In (par), fra diagrammet
    # Egenkomponerte back-9-scorer (se kommentar over) -- hull 17 (indeks 7,
    # par 4, SI 6) er det ENESTE kildebelagte tallet i denne rekken: gross 9.
    back9_scores = [3, 3, 3, 3, 3, 3, 3, 9, 3]  # index 7 = hull 17

    pars = front9_pars + back9_pars
    stroke_index = front9_si + back9_si
    scores = front9_scores + back9_scores
    strokes_received = allocate_strokes_by_index(16, stroke_index)  # HCP 16

    hole17_index = len(front9_pars) + back9_si.index(6)  # hole 17 = 0-indexert 16
    assert hole17_index == 16
    assert pars[hole17_index] == 4 and stroke_index[hole17_index] == 6
    assert strokes_received[hole17_index] == 1  # SI 6 <= 16 -> mottar slag
    assert max_hole_score_for_handicap(4, 1) == 7  # Net Double Bogey, diagrammets "Max 7"

    ags = adjusted_gross_score(scores, pars, strokes_received)
    # Eneste hull som overskrider sin cap er hull 17 (gross 9 -> capped 7):
    # adjusted = gross_total - (9 - 7).
    assert ags == sum(scores) - 2


def test_adjusted_gross_score_unplayed_holes_use_net_par():
    # 9 spilte hull (front) + 9 uspilte (None) -- uspilte fylles med Net Par
    # (TeeCups kildebelagte erstatning for WHS sin upubliserte Expected Score,
    # se ADR-033 og moduldoc i handicap_engine.py).
    pars = [4] * 18
    stroke_index = list(range(1, 19))
    strokes_received = allocate_strokes_by_index(9, stroke_index)  # 9 slag -> 1 på SI 1-9
    scores = [4] * 9 + [None] * 9
    ags = adjusted_gross_score(scores, pars, strokes_received)
    # Spilte 9: par 4, ingen over cap -> 9*4 = 36.
    # Uspilte 9 (SI 10-18, 0 mottatte slag hver) -> Net Par = par + 0 = 4 hver -> 36.
    assert ags == 72


def test_score_differential_formula():
    # Egen tallsjekk mot selve formelen (Rule 5.1a), ingen offisiell
    # diagram-fasit for akkurat denne kombinasjonen -- verifiserer
    # utregningen, ikke bare at funksjonen kjører.
    diff = score_differential(adjusted_gross_score_value=90, course_rating=71.5, slope_rating=128)
    expected = round_half_up_decimal((113 / 128) * (90 - 71.5), 1)
    assert diff == expected == 16.3


def test_handicap_index_initial_three_scores_rule_5_2a_example_1():
    # Rule 5.2a klargjøring: tre differensialer 15,3 / 15,2 / 16,6
    # -> laveste 1 (15,2), justering -2,0 -> initial indeks 13,2.
    idx = handicap_index_from_differentials([15.3, 15.2, 16.6])
    assert idx == 13.2


def test_handicap_index_initial_three_scores_rule_5_2a_example_2():
    # Rule 5.2a klargjøring, andre eksempel: 40,7 / 42,4 / 36,1
    # -> laveste 1 (36,1), justering -2,0 -> initial indeks 34,1.
    idx = handicap_index_from_differentials([40.7, 42.4, 36.1])
    assert idx == 34.1


def test_handicap_index_six_scores_rule_5_2a_example_2_continued():
    # Samme klargjøring, spilleren legger til tre nye: 45,9 / 43,6 / 45,0.
    # Seks totalt -> snitt av laveste 2 (36,1 og 40,7 = 38,4), justering
    # -1,0 -> indeks 37,4.
    idx = handicap_index_from_differentials([40.7, 42.4, 36.1, 45.9, 43.6, 45.0])
    assert idx == 37.4


def test_handicap_index_fewer_than_three_returns_none():
    assert handicap_index_from_differentials([]) is None
    assert handicap_index_from_differentials([20.0, 21.0]) is None


def test_handicap_index_twenty_scores_uses_lowest_eight():
    # Rule 5.2b: 20 differensialer -> snitt av laveste 8, ingen justering.
    diffs = [float(v) for v in range(1, 21)]  # 1..20
    idx = handicap_index_from_differentials(diffs)
    # Laveste 8: 1..8 -> snitt 4,5
    assert idx == 4.5


def test_low_handicap_index_within_window():
    history = [
        (date(2025, 1, 1), 18.0),
        (date(2025, 6, 1), 15.0),
        (date(2025, 12, 1), 20.0),
    ]
    # Vindu 365 dager tilbake fra 2025-12-15 dekker alle tre -> laveste 15.0.
    assert low_handicap_index(history, date(2025, 12, 15)) == 15.0


def test_low_handicap_index_excludes_old_entries():
    history = [
        (date(2023, 1, 1), 5.0),   # for gammel, faller utenfor 365-dagersvinduet
        (date(2025, 11, 1), 15.0),
    ]
    assert low_handicap_index(history, date(2025, 12, 15)) == 15.0


def test_low_handicap_index_empty_returns_none():
    assert low_handicap_index([], date(2025, 1, 1)) is None


def test_apply_index_caps_diagram_5_8():
    # Diagram 5.8: Low Handicap Index-referanse 20,0. Soft cap-trigger +3
    # (23,0), hard cap-tak +5 (25,0).
    assert apply_index_caps(new_index=22.0, low_handicap_index_value=20.0) == 22.0  # under soft cap
    assert apply_index_caps(new_index=23.0, low_handicap_index_value=20.0) == 23.0  # akkurat på triggeren
    # Økning 4,0 -> 3,0 uendret + halvparten av resten (1,0) = 3,5 -> 23,5
    assert apply_index_caps(new_index=24.0, low_handicap_index_value=20.0) == 23.5
    # Stor økning -> hard cap-taket, aldri over 25,0
    assert apply_index_caps(new_index=40.0, low_handicap_index_value=20.0) == 25.0


def test_apply_index_caps_no_lower_limit():
    # Ingen nedre grense -- indeksen kan synke fritt, ingen cap i den retningen.
    assert apply_index_caps(new_index=5.0, low_handicap_index_value=20.0) == 5.0


def test_course_handicap_9_halves_index_rule_6_1b():
    # Rule 6.1b: indeksen HALVERES før den ganges med 9-hulls slope/113 --
    # dette AVVIKER fra 18-hulls-formelen (course_handicap_raw), som IKKE
    # halverer. Verifiserer nettopp dette avviket, siden ingen tallmessig
    # offisiell fasit ble gitt for akkurat denne kombinasjonen i kilden.
    idx, slope9, rating9, par9 = 20.0, 132, 36.1, 36
    ch9 = course_handicap_9_raw(idx, slope9, rating9, par9)
    # Skal IKKE være det samme som å bruke full indeks (ville gitt et annet tall).
    full_index_variant = course_handicap_raw(idx, slope9, rating9, par9)
    assert ch9 != full_index_variant
    expected = (idx / 2.0) * (slope9 / 113.0) + (rating9 - par9)
    assert abs(ch9 - expected) < 1e-9
    assert course_handicap_9(idx, slope9, rating9, par9) == round_half_up(expected)


# ---------------------------------------------------------------------------
# Enkel selvsjekk uten pytest
# ---------------------------------------------------------------------------

if __name__ == "__main__":
    import traceback

    tests = [v for k, v in sorted(globals().items()) if k.startswith("test_") and callable(v)]
    passed = 0
    failed = 0
    for t in tests:
        try:
            t()
            print(f"  ok   {t.__name__}")
            passed += 1
        except Exception:
            print(f"  FEIL {t.__name__}")
            traceback.print_exc()
            failed += 1
    print(f"\n{passed} bestått, {failed} feilet, {len(tests)} totalt")
    raise SystemExit(1 if failed else 0)