# -*- coding: utf-8 -*-
"""Quality-first vector retrieval for document chat."""

from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path
from typing import Any, Dict, List, Optional

import yaml

from foundation.observability.logger.loggering import write_logger as logger


PROJECT_ROOT = Path(__file__).resolve().parents[3]
RETRIEVAL_CONFIG_PATH = PROJECT_ROOT / "config" / "document_chat_retrieval.yaml"


@dataclass(frozen=True)
class RetrievalConfig:
    enabled: bool = True
    child_collection: str = "t_kngs_construction_plan_child"
    recall_top_k: int = 30
    rerank_top_k: int = 8
    submit_top_k: int = 3
    min_vector_similarity: float = 0.45
    min_rerank_score: float = 0.70
    min_qualified_count: int = 1
    max_reference_chars: int = 4000
    max_single_reference_chars: int = 1500
    allow_vector_fallback: bool = False
    allow_unscoped_search: bool = False
    dense_weight: float = 0.7
    sparse_weight: float = 0.3
    ranker_type: str = "weighted"
    warnings: Optional[Dict[str, str]] = None


def load_retrieval_config() -> RetrievalConfig:
    if not RETRIEVAL_CONFIG_PATH.exists():
        return RetrievalConfig(warnings=_default_warnings())

    with open(RETRIEVAL_CONFIG_PATH, "r", encoding="utf-8") as handle:
        raw = yaml.safe_load(handle) or {}

    retrieval = raw.get("retrieval") or {}
    warnings = raw.get("warnings") or _default_warnings()
    return RetrievalConfig(
        enabled=bool(retrieval.get("enabled", True)),
        child_collection=str(retrieval.get("child_collection") or "t_kngs_construction_plan_child"),
        recall_top_k=_to_int(retrieval.get("recall_top_k"), 30),
        rerank_top_k=_to_int(retrieval.get("rerank_top_k"), 8),
        submit_top_k=_to_int(retrieval.get("submit_top_k"), 3),
        min_vector_similarity=_to_float(retrieval.get("min_vector_similarity"), 0.45),
        min_rerank_score=_to_float(retrieval.get("min_rerank_score"), 0.70),
        min_qualified_count=_to_int(retrieval.get("min_qualified_count"), 1),
        max_reference_chars=_to_int(retrieval.get("max_reference_chars"), 4000),
        max_single_reference_chars=_to_int(retrieval.get("max_single_reference_chars"), 1500),
        allow_vector_fallback=bool(retrieval.get("allow_vector_fallback", False)),
        allow_unscoped_search=bool(retrieval.get("allow_unscoped_search", False)),
        dense_weight=_to_float(retrieval.get("dense_weight"), 0.7),
        sparse_weight=_to_float(retrieval.get("sparse_weight"), 0.3),
        ranker_type=str(retrieval.get("ranker_type") or "weighted"),
        warnings=warnings,
    )


class DocumentChatRetrievalService:
    """Build retrieval queries and fetch quality candidates.

    Retrieval is intentionally conservative: when no reliable scope is present
    and unscoped search is disabled, it returns no candidates.
    """

    def __init__(self, config: Optional[RetrievalConfig] = None):
        self.config = config or load_retrieval_config()

    def build_query(self, state: Dict[str, Any]) -> str:
        selected_section = state.get("selected_section") or {}
        project_info = state.get("project_info") or {}
        intent_result = state.get("intent_result") or {}
        section_content = str(selected_section.get("content") or "")
        section_preview = section_content[:1000]

        parts = [
            f"项目名称：{project_info.get('project_name') or project_info.get('name') or ''}",
            f"工程类型：{project_info.get('engineering_type') or project_info.get('project_type') or ''}",
            f"施工位置：{project_info.get('construct_location') or project_info.get('location') or ''}",
            f"章节：{selected_section.get('index', '')} {selected_section.get('title', '')}",
            f"用户需求：{state.get('user_message') or ''}",
            f"归一化需求：{intent_result.get('normalized_instruction') or ''}",
            f"当前章节摘要：{section_preview}",
        ]
        return "\n".join(part for part in parts if part.split("：", 1)[-1].strip())

    def recall(self, state: Dict[str, Any]) -> Dict[str, Any]:
        if not self.config.enabled:
            return self._empty_result("disabled", [], retrieval_method="disabled")

        query = str(state.get("retrieval_query") or "").strip()
        if not query:
            return self._empty_result("no_recall", [self._warning("no_recall")], retrieval_method="empty_query")

        scope = self._extract_scope(state)
        if not self._has_reliable_scope(scope) and not self.config.allow_unscoped_search:
            return self._empty_result(
                "no_scope",
                [self._warning("no_scope")],
                retrieval_method="no_scope",
                retrieval_scope=scope,
            )

        try:
            if scope.get("chapter_level_1") and scope.get("chapter_level_2"):
                retrieval_method = "chapter_similarity"
                candidates = self._recall_by_chapter(scope, query)
            else:
                retrieval_method = "milvus_hybrid_vector"
                candidates = self._recall_by_vector(scope, query)
        except Exception as exc:
            logger.warning(f"[DocumentChat] retrieval failed: {exc}", exc_info=True)
            return self._empty_result(
                "no_recall",
                [self._warning("no_recall")],
                retrieval_method=retrieval_method if "retrieval_method" in locals() else "unknown",
                retrieval_scope=scope,
            )

        candidates = self._clean_candidates(candidates)
        if not candidates:
            return self._empty_result(
                "no_recall",
                [self._warning("no_recall")],
                retrieval_method=retrieval_method,
                retrieval_scope=scope,
            )

        metrics = {
            "recall_count": len(candidates),
            "max_vector_similarity": max((item.get("vector_similarity", 0.0) for item in candidates), default=0.0),
            "scope": {key: value for key, value in scope.items() if value},
            "retrieval_method": retrieval_method,
        }
        return {
            "retrieval_candidates": candidates,
            "retrieval_status": "recalled",
            "retrieval_method": retrieval_method,
            "retrieval_metrics": metrics,
            "warnings": [],
        }

    def _recall_by_chapter(self, scope: Dict[str, Any], query: str) -> List[Dict[str, Any]]:
        from core.construction_write.component.similar_fragment_service import search_similar_fragments

        rows = search_similar_fragments(
            level1=str(scope.get("chapter_level_1") or ""),
            level2=str(scope.get("chapter_level_2") or ""),
            search_text=query,
            top_k=self.config.recall_top_k,
        )
        candidates = []
        for row in rows:
            text = str(row.get("text") or "").strip()
            metadata = {
                "tenant_id": scope.get("tenant_id") or "",
                "project_id": scope.get("project_id") or "",
                "knowledge_base_id": scope.get("knowledge_base_id") or "",
                "file_name": row.get("file_name") or "",
                "chapter_level_1": row.get("chapter_level_1") or scope.get("chapter_level_1") or "",
                "chapter_level_2": row.get("chapter_level_2") or scope.get("chapter_level_2") or "",
                "parent_count": row.get("parent_count", 0),
                "source_scope_valid": True,
            }
            candidates.append(
                {
                    "text": text,
                    "source": metadata.get("file_name") or "向量知识库",
                    "vector_similarity": _to_float(row.get("similarity"), 0.0),
                    "metadata": metadata,
                }
            )
        return candidates

    def _recall_by_vector(self, scope: Dict[str, Any], query: str) -> List[Dict[str, Any]]:
        from foundation.database.base.vector.milvus_vector import MilvusVectorManager

        expr = self._build_filter_expr(scope)
        if not expr:
            return []

        results = MilvusVectorManager().hybrid_search(
            param={"collection_name": self.config.child_collection, "expr": expr},
            query_text=query,
            top_k=self.config.recall_top_k,
            ranker_type=self.config.ranker_type,
            dense_weight=self.config.dense_weight,
            sparse_weight=self.config.sparse_weight,
        )
        candidates = []
        for row in results:
            metadata = self._normalize_metadata(row.get("metadata") or {})
            source_scope_valid = self._metadata_matches_scope(metadata, scope)
            metadata["source_scope_valid"] = source_scope_valid
            candidates.append(
                {
                    "text": str(row.get("text_content") or "").strip(),
                    "source": metadata.get("file_name") or metadata.get("title") or "向量知识库",
                    "vector_similarity": _to_float(row.get("similarity"), 0.0),
                    "metadata": metadata,
                }
            )
        return candidates

    def _extract_scope(self, state: Dict[str, Any]) -> Dict[str, Any]:
        selected = state.get("selected_section") or {}
        context = state.get("document_context") or {}
        project = state.get("project_info") or {}
        filters = context.get("retrieval_filters") if isinstance(context.get("retrieval_filters"), dict) else {}
        filters = filters or project.get("retrieval_filters") if isinstance(project.get("retrieval_filters"), dict) else filters

        def pick(*keys: str) -> str:
            for source in (selected, context, project, filters or {}):
                for key in keys:
                    value = source.get(key) if isinstance(source, dict) else None
                    if value not in (None, ""):
                        return str(value).strip()
            return ""

        return {
            "tenant_id": pick("tenant_id"),
            "project_id": pick("project_id"),
            "knowledge_base_id": pick("knowledge_base_id", "kb_id"),
            "engineering_type": pick("engineering_type", "project_type"),
            "chapter_level_1": pick("chapter_level_1", "level1"),
            "chapter_level_2": pick("chapter_level_2", "level2"),
        }

    @staticmethod
    def _has_reliable_scope(scope: Dict[str, Any]) -> bool:
        if scope.get("chapter_level_1") and scope.get("chapter_level_2"):
            return True
        return bool(scope.get("tenant_id") or scope.get("project_id") or scope.get("knowledge_base_id"))

    def _build_filter_expr(self, scope: Dict[str, Any]) -> str:
        conditions = []
        for key in ("tenant_id", "project_id", "knowledge_base_id", "engineering_type", "chapter_level_1", "chapter_level_2"):
            value = str(scope.get(key) or "").strip()
            if value:
                conditions.append(f"{key} == '{_escape_milvus_string(value)}'")
        return " and ".join(conditions)

    @staticmethod
    def _metadata_matches_scope(metadata: Dict[str, Any], scope: Dict[str, Any]) -> bool:
        required_keys = ["tenant_id", "project_id", "knowledge_base_id", "chapter_level_1", "chapter_level_2"]
        for key in required_keys:
            expected = str(scope.get(key) or "").strip()
            if not expected:
                continue
            actual = str(metadata.get(key) or "").strip()
            if actual and actual != expected:
                return False
        return True

    @staticmethod
    def _normalize_metadata(metadata: Any) -> Dict[str, Any]:
        if isinstance(metadata, dict):
            return dict(metadata)
        if isinstance(metadata, str) and metadata.strip():
            try:
                loaded = yaml.safe_load(metadata)
                return dict(loaded) if isinstance(loaded, dict) else {}
            except Exception:
                return {}
        return {}

    def _clean_candidates(self, candidates: List[Dict[str, Any]]) -> List[Dict[str, Any]]:
        cleaned = []
        seen = set()
        for item in candidates:
            text = str(item.get("text") or "").strip()
            if len(text) < 20:
                continue
            dedupe_key = text[:300]
            if dedupe_key in seen:
                continue
            seen.add(dedupe_key)
            metadata = item.get("metadata") if isinstance(item.get("metadata"), dict) else {}
            cleaned.append(
                {
                    "text": text[: self.config.max_single_reference_chars],
                    "source": str(item.get("source") or metadata.get("file_name") or "向量知识库"),
                    "vector_similarity": _to_float(item.get("vector_similarity"), 0.0),
                    "metadata": metadata,
                }
            )
        cleaned.sort(key=lambda item: item.get("vector_similarity", 0.0), reverse=True)
        return cleaned[: self.config.recall_top_k]

    def _empty_result(
        self,
        status: str,
        warnings: List[str],
        retrieval_method: str = "",
        retrieval_scope: Optional[Dict[str, Any]] = None,
    ) -> Dict[str, Any]:
        return {
            "retrieval_candidates": [],
            "retrieval_status": status,
            "retrieval_method": retrieval_method,
            "retrieval_metrics": {
                "recall_count": 0,
                "retrieval_method": retrieval_method,
                "scope": {key: value for key, value in (retrieval_scope or {}).items() if value},
            },
            "warnings": warnings,
        }

    def _warning(self, key: str) -> str:
        warnings = self.config.warnings or _default_warnings()
        return warnings.get(key) or ""


def _default_warnings() -> Dict[str, str]:
    return {
        "no_scope": "缺少可靠的知识库检索范围，本次未引用向量库内容。",
        "no_recall": "未召回可信知识库内容，本次回答不引用向量库。",
        "low_confidence": "未找到可信度足够的知识库片段，本次未引用向量库内容。",
        "rerank_failed": "知识库片段重排不可用，本次未引用向量库内容。",
    }


def _escape_milvus_string(value: str) -> str:
    return str(value).replace("\\", "\\\\").replace("'", "\\'")


def _to_int(value: Any, default: int) -> int:
    try:
        return int(value)
    except (TypeError, ValueError):
        return default


def _to_float(value: Any, default: float) -> float:
    try:
        return float(value)
    except (TypeError, ValueError):
        return default