# tools/excel_merge.py
from common.logger import tool_logger, error_logger
import pandas as pd

def read_file(file_path):
    ext = file_path.lower().split(".")[-1]

    if ext in ["xlsx", "xls"]:
        df = pd.read_excel(file_path, dtype=str)

    elif ext == "csv":
        df = None
        for enc in ["utf-8", "gbk", "gb18030"]:
            try:
                df = pd.read_csv(file_path, encoding=enc, dtype=str)
                break
            except:
                pass

        if df is None:
            tool_logger.exception("CSV编码无法识别")
            raise Exception("CSV编码无法识别")

    else:
        tool_logger.exception("仅支持 xlsx/xls/csv")
        raise Exception("仅支持 xlsx/xls/csv")

    df.columns = df.columns.astype(str).str.strip()
    for c in df.columns:
        df[c] = df[c].astype(str).str.strip()

    return df


def merge_df(df1, df2, key1, key2, join_type):
    if key1 not in df1.columns:
        tool_logger.exception(f"文件1不存在字段：{key1}")
        raise Exception(f"文件1不存在字段：{key1}")

    if key2 not in df2.columns:
        tool_logger.exception(f"文件2不存在字段：{key2}")
        raise Exception(f"文件2不存在字段：{key2}")

    merged_df = pd.merge(
        df1,
        df2,
        left_on=key1,
        right_on=key2,
        how=join_type
    )

    return merged_df


def export_excel(df, path):
    df.to_excel(path, index=False)

def build_preview(df):
    return df.head(100).fillna("").to_html(
        classes="table table-bordered table-hover preview-table",
        table_id="previewTable",
        index=False,
        border=0
    )