import os
import time
import shutil
from pathlib import Path
from fastapi import APIRouter, UploadFile, File, HTTPException, Depends
from fastapi.responses import FileResponse
from auth import get_current_user
from services.sentence_transformer_service import SentenceTransformerService, sentence_transformer_service
from data_lib.input_name_data import InputNameData
from data_lib.base_data import COL_NAME_SENTENCE
from mapping_lib.name_mapping_helper import NameMappingHelper
from config import UPLOAD_DIR, OUTPUT_DIR

router = APIRouter()

@router.post("/predict")
async def predict(
    current_user=Depends(get_current_user),
    file: UploadFile = File(...),
    sentence_service: SentenceTransformerService = Depends(lambda: sentence_transformer_service)
):
    """
    Process an input CSV file and return standardized names (requires authentication)
    """
    if not file.filename.endswith(".csv"):
        raise HTTPException(status_code=400, detail="Only CSV files are supported")

    # Save uploaded file
    timestamp = int(time.time())
    input_file_path = os.path.join(UPLOAD_DIR, f"input_{timestamp}_{current_user.username}.csv")
    output_file_path = os.path.join(OUTPUT_DIR, f"output_{timestamp}_{current_user.username}.csv")

    try:
        with open(input_file_path, "wb") as buffer:
            shutil.copyfileobj(file.file, buffer)
    finally:
        file.file.close()

    try:
        # Process input data
        inputData = InputNameData(sentence_service.dic_standard_subject)
        inputData.load_data_from_csv(input_file_path)
        inputData.process_data()
        input_name_sentences = inputData.dataframe[COL_NAME_SENTENCE]
        input_name_sentence_embeddings = sentence_service.sentenceTransformerHelper.create_embeddings(input_name_sentences)
        
        # Create similarity matrix
        similarity_matrix = sentence_service.sentenceTransformerHelper.create_similarity_matrix_from_embeddings(
            sentence_service.sample_name_sentence_embeddings,
            input_name_sentence_embeddings
        )

        # Map standard names
        nameMappingHelper = NameMappingHelper(
            sentence_service.sentenceTransformerHelper,
            inputData,
            sentence_service.sampleData,
            input_name_sentence_embeddings,
            sentence_service.sample_name_sentence_embeddings,
            similarity_matrix,
        )
        df_predicted = nameMappingHelper.map_standard_names()

        # Create output dataframe and save to CSV
        column_to_keep = ['シート名', '行', '科目', '分類', '名称', '摘要', '備考']
        output_df = inputData.dataframe[column_to_keep].copy()
        output_df.reset_index(drop=False, inplace=True)
        output_df.loc[:, "出力_科目"] = df_predicted["出力_科目"]
        output_df.loc[:, "出力_項目名"] = df_predicted["出力_項目名"]
        output_df.loc[:, "出力_確率度"] = df_predicted["出力_確率度"]

        # Save with utf_8_sig encoding for Japanese Excel compatibility
        output_df.to_csv(output_file_path, index=False, encoding="utf_8_sig")

        return FileResponse(
            path=output_file_path,
            filename=f"output_{Path(file.filename).stem}.csv",
            media_type="text/csv",
            headers={
                "Content-Disposition": f'attachment; filename="output_{Path(file.filename).stem}.csv"',
                "Content-Type": "application/x-www-form-urlencoded",
            },
        )

    except Exception as e:
        print(f"Error processing file: {e}")
        raise HTTPException(status_code=500, detail=str(e))