"""人生时间键与章节排序键（纯函数）。"""

from datetime import datetime, timezone

from app.agents.memoir.prompts import (
    NARRATIVE_MERGE_EXISTING_MAX_CHARS,
    clip_existing_story_body_for_merge,
)
from app.features.story.time_hints import (
    infer_story_time_start,
    life_sort_key_parts,
    parse_time_start_year,
    parse_year_from_title,
)


def test_parse_year_from_title() -> None:
    assert parse_year_from_title("1999年 · 小学往事") == 1999
    assert parse_year_from_title("2005 · 标题") == 2005
    assert parse_year_from_title("无年份标题") is None


def test_parse_time_start_year() -> None:
    assert parse_time_start_year("1999") == 1999
    assert parse_time_start_year("1999-03") == 1999
    assert parse_time_start_year(None) is None


def test_infer_story_time_start_prefers_existing() -> None:
    assert (
        infer_story_time_start(
            title="2010 · x",
            canonical_markdown="",
            existing_time_start="2001",
        )
        == "2001"
    )


def test_infer_story_time_start_from_title() -> None:
    assert (
        infer_story_time_start(
            title="2008年 · 某件事",
            canonical_markdown="正文没有年份",
            existing_time_start=None,
        )
        == "2008"
    )


def test_infer_story_time_start_from_body() -> None:
    assert (
        infer_story_time_start(
            title="无年标题",
            canonical_markdown="那是2012年的夏天。",
            existing_time_start=None,
        )
        == "2012"
    )


def test_clip_existing_story_body_for_merge_truncates() -> None:
    short = "a" * 100
    assert clip_existing_story_body_for_merge(short) == short
    long = "b" * (NARRATIVE_MERGE_EXISTING_MAX_CHARS + 50)
    clipped = clip_existing_story_body_for_merge(long)
    assert "省略" in clipped
    # 头+尾+提示语可能略长于原串若干字节，但应远小于未截断的线性增长
    assert len(clipped) <= len(long) + 400


def test_life_sort_key_parts_order() -> None:
    t0 = datetime(2020, 1, 1, tzinfo=timezone.utc)
    t1 = datetime(2021, 1, 1, tzinfo=timezone.utc)
    a = life_sort_key_parts(
        time_start="1999",
        title=None,
        created_at=t1,
        story_id="b",
    )
    b = life_sort_key_parts(
        time_start="2005",
        title=None,
        created_at=t0,
        story_id="a",
    )
    assert a < b