# -*- coding: utf-8 -*-
"""多路文档对话检索结果的 RRF 融合合并。"""

from __future__ import annotations

from typing import Any, Dict, List

from core.document_chat.retrieval.candidate import build_candidate_key, merge_metadata
from core.document_chat.retrieval.config import RetrievalConfig
from core.document_chat.retrieval.scope import metadata_matches_scope, select_tag_terms
from core.document_chat.retrieval.utils import to_float


def merge_recall_results(
    source_results: Dict[str, List[Dict[str, Any]]],
    scope: Dict[str, Any],
    keywords: List[str],
    config: RetrievalConfig,
) -> List[Dict[str, Any]]:
    """多路召回结果 RRF 融合合并。"""
    weights = {
        "parent_vector": config.parent_vector_weight,
        "child_locator": config.child_locator_weight,
        "tag": config.tag_weight,
        "chapter_similarity": config.chapter_similarity_weight,
    }
    merged: Dict[str, Dict[str, Any]] = {}

    for source, candidates in source_results.items():
        weight = weights.get(source, 0.0)
        for rank, item in enumerate(candidates or [], start=1):
            key = str(item.get("candidate_key") or build_candidate_key(item, item.get("text")))
            if not key:
                continue
            if key not in merged:
                candidate = dict(item)
                candidate["candidate_key"] = key
                candidate["source_hits"] = {}
                candidate["fusion_score"] = 0.0
                merged[key] = candidate

            current = merged[key]
            current["fusion_score"] = to_float(current.get("fusion_score"), 0.0) + weight / (config.rrf_k + rank)
            current["vector_similarity"] = max(
                to_float(current.get("vector_similarity"), 0.0),
                to_float(item.get("vector_similarity"), 0.0),
            )
            current.setdefault("source_hits", {})[source] = {
                "rank": rank,
                "vector_similarity": to_float(item.get("vector_similarity"), 0.0),
            }
            merge_metadata(current, item)

    for candidate in merged.values():
        source_hits = candidate.get("source_hits") if isinstance(candidate.get("source_hits"), dict) else {}
        metadata = candidate.get("metadata") if isinstance(candidate.get("metadata"), dict) else {}
        if len(source_hits) > 1:
            candidate["fusion_score"] += config.multi_source_bonus
        if metadata_matches_scope(metadata, scope):
            candidate["fusion_score"] += config.scope_bonus
        candidate["fusion_score"] += calc_tag_bonus(candidate, keywords, config)

    return sorted(merged.values(), key=lambda item: item.get("fusion_score", 0.0), reverse=True)[: config.recall_top_k]


def calc_tag_bonus(candidate: Dict[str, Any], keywords: List[str], config: RetrievalConfig) -> float:
    """计算标签匹配加分：关键词精确匹配 tag_list 加分更多，仅出现在文本中加分较少。"""
    metadata = candidate.get("metadata") if isinstance(candidate.get("metadata"), dict) else {}
    text = " ".join(
        str(value or "")
        for value in (
            candidate.get("text"),
            metadata.get("tag_list"),
            " ".join(metadata.get("matched_child_texts") or []),
        )
    )
    bonus = 0.0
    for keyword in select_tag_terms(
        keywords,
        config.tag_terms_limit,
        generic_terms=config.tag_generic_terms,
        priority_terms=config.tag_priority_terms,
    ):
        if not keyword:
            continue
        if keyword in str(metadata.get("tag_list") or ""):
            bonus += config.tag_exact_bonus
        elif keyword in text:
            bonus += config.tag_partial_bonus
    return bonus