import math
from utils.Database import *


# 查询数据条数
async def get_total_data_count(total_data_sql):
    total_data_count = 0
    total_data_count_sql = "select count(*) as num from (" + total_data_sql + ") as temp_table"
    result = await find_by_sql(total_data_count_sql,())
    row = result[0] if result else None
    if row:
        total_data_count = row.get("num")
    return total_data_count


def get_page_by_total_row(total_data_count, page_number, page_size):
    total_page = (page_size != 0) and math.floor((total_data_count + page_size - 1) / page_size) or 0
    if page_number <= 0:
        page_number = 1
    if 0 < total_page < page_number:
        page_number = total_page
    offset = page_size * page_number - page_size
    limit = page_size
    return total_data_count, total_page, offset, limit


async def get_page_data_by_sql(total_data_sql: str, page_number: int, page_size: int):
    total_row: int = 0
    total_page: int = 0
    total_data_sql = total_data_sql.replace(";", "")
    total_data_sql = total_data_sql.replace(" FROM ", " from ")

    # 查询总数
    total_data_count = await get_total_data_count(total_data_sql)
    if total_data_count == 0:
        return {"page_number": page_number, "page_size": page_size, "total_row": 0, "total_page": 0, "list": []}
    else:
        total_row, total_page, offset, limit = get_page_by_total_row(total_data_count, page_number, page_size)

    # 构造执行分页查询的sql语句
    page_data_sql = total_data_sql + " LIMIT %d offset %d " % (limit, offset)
    print(page_data_sql)
    # 执行分页查询
    page_data = await find_by_sql(page_data_sql, ())
    if page_data:
        return {"page_number": page_number, "page_size": page_size, "total_row": total_row, "total_page": total_page, "list": page_data}
    else:
        return {"page_number": page_number, "page_size": page_size, "total_row": 0, "total_page": 0, "list": []}