"""summarize_units 단위테스트 (presegment PR1 — 순수함수·fixture).

핵심 불변식:
  - estimate_tokens = PR0 캘리브레이션(한글 0.529 · 기타 0.217 tok/char) 정확 재현.
  - greedy_pack: 순서 보존·인접만·cap 준수·단독 초과 leaf=over_cap 전용 유닛·텍스트 손실 0
    (구 deep_summary head/mid/tail 가운데 폐기 버그의 반대 성질).
  - gate 3-way: 0=auto / (0,40]=hybrid / >40=whole (경계 포함).
  - plan_summarize_units: trigger 이하=single(현행 단일콜 유지=무회귀) / 초과=map_reduce.

pytest + 단독 실행 양쪽 지원:
  PYTHONPATH=. .venv/bin/pytest tests/summarize_units/ -q
"""
from __future__ import annotations

from app.services.hier_decomp.builder import HierNode
from app.services.summarize_units import (
    CAP_TOKENS,
    TRIGGER_TOKENS,
    SummarizeUnit,
    estimate_tokens,
    extract_leaves,
    gate,
    greedy_pack,
    over_pct,
    plan_summarize_units,
)


def _leaf(idx: int, text: str, title: str | None = None) -> HierNode:
    return HierNode(idx=idx, parent_idx=None, level=1, node_type=None,
                    section_title=title, heading_path=title, text=text)


# ---------- estimate_tokens ----------

def test_estimate_tokens_korean_calibration():
    # 한글 1000자 → 529 tok (PR0: 0.529 tok/char)
    assert estimate_tokens("가" * 1000) == 529


def test_estimate_tokens_english_calibration():
    # 비한글 1000자 → 217 tok (PR0: 0.217 tok/char)
    assert estimate_tokens("a" * 1000) == 217


def test_estimate_tokens_mixed_and_empty():
    assert estimate_tokens("") == 0
    mixed = "가" * 100 + "a" * 100
    assert estimate_tokens(mixed) == round(100 * 0.529 + 100 * 0.217)


# ---------- greedy_pack ----------

def test_greedy_pack_adjacency_and_cap():
    # 4000tok 짜리 한글 leaf 4개 (4000/0.529 ≈ 7562자) → cap 12000 이면 [3개, 1개]... 아니
    # 4000*3=12000 = cap 정확 경계(<=cap 허용) → [1,2,3] + [4]
    body = "가" * 7562  # ≈ 3999~4000 tok
    leaves = [_leaf(i, body, f"s{i}") for i in range(4)]
    units = greedy_pack(leaves, cap=12_000)
    assert len(units) == 2
    assert [len(u.section_titles) for u in units] == [3, 1]
    # 순서 보존
    assert units[0].section_titles == ["s0", "s1", "s2"]
    assert units[1].section_titles == ["s3"]
    # cap 준수
    assert all(u.est_tokens <= 12_000 for u in units)


def test_greedy_pack_oversized_leaf_gets_own_unit():
    small = "가" * 1000            # ≈ 529 tok
    big = "가" * 30_000            # ≈ 15,870 tok > CAP
    leaves = [_leaf(0, small, "a"), _leaf(1, big, "mega"), _leaf(2, small, "b")]
    units = greedy_pack(leaves, cap=CAP_TOKENS)
    assert len(units) == 3
    assert units[1].over_cap and units[1].section_titles == ["mega"]
    assert not units[0].over_cap and not units[2].over_cap
    # 인접성: 초과 leaf 가 앞뒤 pack 을 넘나들며 합쳐지지 않음
    assert units[0].section_titles == ["a"] and units[2].section_titles == ["b"]


def test_greedy_pack_no_text_loss():
    leaves = [_leaf(i, f"본문{i} " + "가" * 500, f"s{i}") for i in range(7)]
    units = greedy_pack(leaves, cap=1_000)
    joined = "\n\n".join(u.text for u in units)
    for leaf in leaves:
        assert leaf.text in joined  # 커버리지 — 중간 폐기 0


def test_greedy_pack_empty():
    assert greedy_pack([]) == []


# ---------- over_pct + gate ----------

def test_over_pct_and_gate_boundaries():
    assert gate(0.0) == "auto"
    assert gate(0.01) == "hybrid"
    assert gate(40.0) == "hybrid"
    assert gate(40.01) == "whole"
    assert gate(100.0) == "whole"


def test_over_pct_computation():
    # leaf: 6000tok + 18000tok(초과) → over% = 18000/24000 = 75%
    l_small = _leaf(0, "가" * round(6000 / 0.529), "a")
    l_big = _leaf(1, "가" * round(18000 / 0.529), "b")
    pct = over_pct([l_small, l_big], cap=CAP_TOKENS)
    assert 74.0 < pct < 76.0
    assert over_pct([], cap=CAP_TOKENS) == 0.0
    assert over_pct([l_small], cap=CAP_TOKENS) == 0.0


# ---------- plan_summarize_units (fixture md) ----------

def _md_doc(sections: int, chars_per_section: int, ch: str = "가") -> str:
    parts = []
    for i in range(sections):
        parts.append(f"# 제{i+1}장 섹션{i}\n\n" + ch * chars_per_section)
    return "\n\n".join(parts)


def test_plan_small_doc_stays_single():
    md = _md_doc(3, 1000)  # ≈ 3×529 tok ≪ trigger
    plan = plan_summarize_units(md)
    assert plan.mode == "single" and plan.tier is None and plan.units == []
    assert plan.total_est_tokens <= TRIGGER_TOKENS


def test_plan_large_doc_auto_tier():
    # 섹션 20개 × ≈4000tok = ≈80K tok > trigger, 전 섹션 < cap → auto
    md = _md_doc(20, 7562)
    plan = plan_summarize_units(md)
    assert plan.mode == "map_reduce"
    assert plan.tier == "auto" and plan.over_pct == 0.0
    assert len(plan.units) >= 2
    assert all(u.est_tokens <= CAP_TOKENS for u in plan.units)


def test_plan_mega_section_whole_tier():
    # 작은 섹션 2 + 초대형 1(≈53K tok — 전체의 >40%) → whole
    md = (_md_doc(2, 7562)
          + "\n\n# 메가섹션\n\n" + "가" * 100_000)
    plan = plan_summarize_units(md)
    assert plan.mode == "map_reduce"
    assert plan.tier == "whole" and plan.over_pct > 40.0
    assert any(u.over_cap for u in plan.units)


def test_plan_hybrid_tier():
    # 정상 섹션 15개(≈60K tok) + 초과 섹션 1개(≈15.9K tok) → over% ≈ 21% → hybrid
    md = _md_doc(15, 7562) + "\n\n# 초과섹션\n\n" + "가" * 30_000
    plan = plan_summarize_units(md)
    assert plan.mode == "map_reduce"
    assert plan.tier == "hybrid"
    assert 0.0 < plan.over_pct <= 40.0
    over_units = [u for u in plan.units if u.over_cap]
    assert len(over_units) == 1  # hybrid 시 클로드 대상 = 이 유닛들만


def test_plan_headingless_giant_is_whole():
    # 헤딩 없는 거대 EN 문서 — leaf 1개 전체 초과 → over% 100 → whole (PR0: EN 책 다수)
    md = "x" * 200_000  # ≈ 43K tok > trigger, 단일 leaf > cap
    plan = plan_summarize_units(md)
    assert plan.mode == "map_reduce" and plan.tier == "whole"


def test_plan_deterministic():
    md = _md_doc(10, 7562)
    p1, p2 = plan_summarize_units(md), plan_summarize_units(md)
    assert p1 == p2


if __name__ == "__main__":
    import sys
    fns = [v for k, v in sorted(globals().items()) if k.startswith("test_")]
    for fn in fns:
        fn()
        print(f"ok {fn.__name__}")
    print(f"{len(fns)} passed (standalone)")
    sys.exit(0)