"""Implement application-layer logic for services."""

from __future__ import annotations

import os
import tempfile
import uuid
from dataclasses import dataclass

from loguru import logger

from app.domain.documents import (
    ChunkBuilder,
    Document,
    DocumentBinaryStore,
    DocumentParser,
    DocumentRepository,
    DocumentStatus,
)
from app.domain.retrieval import EmbeddingProvider, VectorIndex
# Keep orchestration logic centralized so use-case flow stays easy to trace.



@dataclass
class DocumentProcessResult:
    """Represent document process result data."""
    doc_id: str
    doc_name: str
    status: str
    message: str
    num_chunks: int = 0
    summary: str = ""
    summary_latency_ms: int = 0


class DocumentCommandService:
    """Provide the Document Command Service service."""
    def __init__(
        self,
        *,
        document_repository: DocumentRepository,
        binary_store: DocumentBinaryStore,
        parser: DocumentParser,
        chunk_builder: ChunkBuilder,
        embedding_provider: EmbeddingProvider,
        vector_index: VectorIndex,
    ) -> None:
        """Initialize the Document Command Service instance."""
        self.document_repository = document_repository
        self.binary_store = binary_store
        self.parser = parser
        self.chunk_builder = chunk_builder
        self.embedding_provider = embedding_provider
        self.vector_index = vector_index

    def upload_and_process(
        self,
        *,
        doc_id: str | None = None,
        file_name: str,
        content: bytes,
        content_type: str,
        doc_name: str | None,
        regulation_type: str,
        version: str,
        generate_summary: bool,
    ) -> DocumentProcessResult:
        """Handle upload and process for the Document Command Service instance."""
        doc_id = doc_id or str(uuid.uuid4())[:8]
        final_doc_name = doc_name or file_name
        object_name = f"{doc_id}/{file_name}"

        document = Document(
            doc_id=doc_id,
            doc_name=final_doc_name,
            file_name=file_name,
            object_name=object_name,
            content_type=content_type,
            size_bytes=len(content),
            regulation_type=regulation_type,
            version=version,
            metadata={"generate_summary": generate_summary},
        )
        self.document_repository.create(document)

        temp_path = ""
        try:
            self.binary_store.save(
                object_name=object_name,
                data=content,
                content_type=content_type,
                metadata={"doc_id": doc_id},
            )
            self.document_repository.update_status(doc_id, DocumentStatus.STORED)

            suffix = os.path.splitext(file_name)[1]
            with tempfile.NamedTemporaryFile(delete=False, suffix=suffix) as temp_file:
                temp_file.write(content)
                temp_path = temp_file.name

            parsed_document = self.parser.parse(
                file_path=temp_path,
                doc_id=doc_id,
                doc_name=final_doc_name,
            )
            self.document_repository.update_status(
                doc_id,
                DocumentStatus.PARSED,
                parser_name=parsed_document.parser_name,
                metadata={"structure_nodes": len(parsed_document.structure_nodes)},
            )

            chunks = self.chunk_builder.build(
                parsed_document=parsed_document,
                regulation_type=regulation_type,
                version=version,
            )
            if not chunks:
                raise ValueError("解析完成但没有生成可入库的 chunks")

            vectors = self.embedding_provider.embed_texts([chunk.embedding_text for chunk in chunks])
            inserted = self.vector_index.upsert(chunks, vectors)
            if inserted != len(chunks):
                logger.warning("Milvus upsert count mismatched: inserted={}, chunks={}", inserted, len(chunks))

            self.document_repository.update_status(
                doc_id,
                DocumentStatus.INDEXED,
                chunk_count=len(chunks),
                summary="",
                summary_latency_ms=0,
                index_name=self.vector_index.health().get("collection_name", ""),
            )
            stored = self.document_repository.get(doc_id)
            return DocumentProcessResult(
                doc_id=doc_id,
                doc_name=final_doc_name,
                status=(stored.status.value if stored else DocumentStatus.INDEXED.value),
                message="处理成功",
                num_chunks=len(chunks),
                summary=stored.summary if stored else "",
                summary_latency_ms=stored.summary_latency_ms if stored else 0,
            )
        except Exception as exc:
            logger.exception("文档处理失败: doc_id={}", doc_id)
            self.document_repository.update_status(
                doc_id,
                DocumentStatus.FAILED,
                error_message=str(exc),
            )
            return DocumentProcessResult(
                doc_id=doc_id,
                doc_name=final_doc_name,
                status=DocumentStatus.FAILED.value,
                message=f"文档处理失败: {exc}",
            )
        finally:
            if temp_path and os.path.exists(temp_path):
                try:
                    os.remove(temp_path)
                except OSError:
                    logger.warning("临时文件清理失败: {}", temp_path)


class DocumentQueryService:
    """Provide the Document Query Service service."""
    def __init__(self, *, document_repository: DocumentRepository, binary_store: DocumentBinaryStore) -> None:
        """Initialize the Document Query Service instance."""
        self.document_repository = document_repository
        self.binary_store = binary_store

    def get(self, doc_id: str) -> Document | None:
        """Handle get for the Document Query Service instance."""
        return self.document_repository.get(doc_id)

    def list_documents(self, limit: int | None = None) -> list[Document]:
        """List documents for the Document Query Service instance."""
        return self.document_repository.list(limit=limit)

    def download(self, doc_id: str) -> tuple[Document, bytes]:
        """Handle download for the Document Query Service instance."""
        document = self.document_repository.get(doc_id)
        if not document:
            raise FileNotFoundError(f"文档不存在: {doc_id}")
        return document, self.binary_store.read(document.object_name)