"""世谱匹配引擎：关键词 / 正则 / selective / constant / 递归扫描。

纯逻辑，无 IO。扫描文本由调用方（集成层）从对话历史截取后传入。
"""

from __future__ import annotations

import re

from app.modules.lorebook.types import LorebookBook, LorebookEntry, MatchedEntry

_RECURSION_MAX_ITERATIONS = 5


def match_entries(book: LorebookBook, scan_text: str) -> list[MatchedEntry]:
    """返回命中的条目（含 constant 与关键词命中）；递归扫描按 book 配置。"""
    matched: list[MatchedEntry] = []
    for entry in book.entries:
        if not entry.enabled:
            continue
        if entry.constant:
            matched.append(MatchedEntry(entry=entry, reason="constant"))
            continue
        if _entry_matches(entry, scan_text):
            matched.append(MatchedEntry(entry=entry, reason="key"))

    if book.recursive_scanning:
        matched = _expand_recursive(matched, book, scan_text)
    return matched


def _entry_matches(entry: LorebookEntry, scan_text: str) -> bool:
    if entry.selective and entry.secondary_keys:
        return _any_key_hit(entry.keys, entry, scan_text) and _any_key_hit(
            entry.secondary_keys, entry, scan_text
        )
    return _any_key_hit(entry.keys, entry, scan_text)


def _any_key_hit(keys: list[str], entry: LorebookEntry, scan_text: str) -> bool:
    for key in keys:
        if not key:
            continue
        if entry.use_regex:
            flags = 0 if entry.case_sensitive else re.IGNORECASE
            try:
                if re.search(key, scan_text, flags):
                    return True
            except re.error:
                # 非法正则降级为字面量包含
                pass
        else:
            hay = scan_text if entry.case_sensitive else scan_text.casefold()
            needle = key if entry.case_sensitive else key.casefold()
            if needle in hay:
                return True
    return False


def _expand_recursive(
    matched: list[MatchedEntry], book: LorebookBook, original_text: str
) -> list[MatchedEntry]:
    """已命中条目的 content 追加进扫描文本，再扫未命中条目；限迭代防振荡。"""
    hit_ids = {m.entry.id for m in matched}
    pool = list(matched)
    extra_text = original_text + "\n" + "\n".join(m.entry.content for m in matched)

    for _ in range(_RECURSION_MAX_ITERATIONS):
        grew = False
        for entry in book.entries:
            if entry.id in hit_ids or not entry.enabled or entry.constant:
                continue
            if _entry_matches(entry, extra_text):
                pool.append(MatchedEntry(entry=entry, reason="recursive"))
                hit_ids.add(entry.id)
                extra_text += "\n" + entry.content
                grew = True
        if not grew:
            break
    return pool