#!/usr/bin/env python3
# A set of functions and types to be included for general use. 
from enum import Enum
from typing import * 
import time
import modin.pandas as pd
from dataclasses import dataclass

# Local imports
from utiltypes import *


# Returns a displayable time, use e.g. with print(f"{delta_now(time_begin)}")
def delta_now(t: float, dp: int = 2) -> float:
    return round(time.time() - t, dp)

def ask_file(prompt: str = "What file should be opened: ") -> str:
    filename = input(prompt)
    return filename

def open_file(file: str) -> pd.DataFrame:
    if file.endswith(".csv"):
        return pd.read_csv(file)
    else:
        return pd.read_excel(file)

# Returns None if successfully saved, else a str error message.
# TODO: add error handling.
def save_df(df: pd.DataFrame, filetype: Filetype, name: str, sheet_name = None):
    if sheet_name == None:
        sheet_name = name

    if filetype == Filetype.Excel:
        df.to_excel(f"{name}.xlsx", sheet_name = f"{sheet_name}", index = False)
    else:
        df.to_csv(f"{name}.csv", index = False)

@dataclass
class PrintOptions:
    update_user: bool
    show_timings: bool

def print_noendl(s: str):
    print(s, end = '', flush = True)

def reprint_noendl(s: str):
    print(f'\r{s}', end = '', flush = True)

# Please supply your own \n if you need it. 
def cond_print(print_options: PrintOptions, s: str, timing_str: str = None, suffix = ""):
    if timing_str and print_options.show_timings: 
        print(s, timing_str, end = "", flush = True)
    elif print_options.update_user: 
        print(s, end = "", flush = True)
    print(suffix, end = "", flush = True)

@dataclass
class AskOpenFileReply:
    df: pd.DataFrame
    fname: str
    sheet: str
    time_to_open_file: float

# Asks for a filename, and opens it; keeps opening until a valid file passed.
def ask_open_file(show_timings: bool = True) -> AskOpenFileReply:
    while True:
        try:
            file = ask_file()
            if file.lower().strip() in [ "quit", "exit" ]:
                print("Quitting...")
                quit()

            print("Opening file... ", end="", flush=True)
            # TODO: add in to open a specific sheet; prompt if more than one 
            # sheet. At present it just opens the first one. Use optparam
            # sheet_name=, with either str of sheet name or int index (deflt 0)
            start_time = time.time()
            df = open_file(file)
            time_taken = time.time() - start_time
            if show_timings: print(f" opened in {round(time_taken, 2)}s!")
            else:            print( " opened!")
            break
        except Exception as exc: 
            print(" File failed to open or could not be found.", flush=True)
            print(f"Details: {exc}")

    # TODO: make `sheet` sheet value when I add this logic.
    reply = AskOpenFileReply(df = df, fname = file, sheet = "", time_to_open_file = time_taken) 
    return reply

def ask_excel_or_csv(given: str = None, prompt: bool = True) -> Filetype:
    # prompt: if False, throw if given not valid instead of prompting the user.
    exit_options  = [ "exit", "quit" ]
    excel_options = [ "xl", "excel", "xlsx", ".xlsx" ]
    csv_options   = [ "csv", ".csv" ]

    if given:
        given = given.lower().strip()
        if given in exit_options:
            quit()
        elif given in excel_options:
            return Filetype.Excel
        elif given in csv_options:
            return Filetype.Csv
        # Do not add an else clause as we need to handle the case when `given`
        # is `None` in the below prompt.

    if not prompt:
        # TODO: change this to be a more specific exception type.
        raise Exception(f"ask_excel_or_csv: passed {given} as parameter with prompt == False")

    answer = input("Should I output as `.xlsx` or `.csv` (`csv` is much faster)? [csv, excel, quit] ")
    answer = answer.lower().strip()
    while True:
        if answer in exit_options:
            quit()
        elif answer in csv_options:
            return Filetype.Csv
        elif answer in excel_options:
            return Filetype.Excel
        else:
            print("Invalid input - I want one of `csv`, `excel`, or `quit`.")