Timestamp Offset

"""
Need to offset some timestamps in a YouTube comment by a constant value? This program is for you.
I made this to fix any comments with timestamps on YouTube livestreams that had been edited after the fact.
"""


numbers = ["0","1","2","3","4","5","6","7","8","9"]

#__________________________________________________________________________________________________________


def convert(time, mode):

    if mode == "to seconds":

        #print("debugme:",time)
        if time[0] != '-': positive = True

        else:
            positive = False
            time = time[1:]

        time += ':' # Marks end of string

        hms = 0
        number = ""
        seconds = 0

        #print("debugpos:",positive)

        for char in time:

            if char in numbers: number += char

            elif char == ":":
                if hms == 0: seconds += int(number) * 3600 # Convert hours to seconds
                elif hms == 1: seconds += int(number) * 60 # Convert minutes to seconds
                else: seconds += int(number) # No need to convert seconds any further.
                hms += 1  # Increment to move onto h/m/s.
                number = "" # Reset


        if positive: return seconds
        return -seconds


    elif mode == "to h:m:s":
        hours = time // 3600
        minutes = str( (time % 3600) // 60 ).rjust(2, '0')
        seconds = str( (time % 3600) % 60  ).rjust(2, '0')

        return f"{hours}:{minutes}:{seconds}"


#__________________________________________________________________________________________________________


def query():
    filename = input("Enter file name: ")
    #filename = filename + ".txt"


    while True:
        offset = input("\nEnter offset: ") # Example input: "0:29:44"

        if offset[0] == "+":
            sign = "+"
            offset = offset[1:]
        elif offset[0] == "-":
            sign = "-"
            offset = offset[1:]
        else:
            print("INFO: ± ommitted, defaulting to negative.")
            sign = "-"


        # Error handling
        invalid = False

        if len(offset) != 7:
            print("Invalid! Timestamp must be in this form ±h:mm:ss\n")
            continue
        for char in offset:
            if (char not in numbers) and (char != ':'):
                print("Invalid! Timestamp must only contain numbers and colons (:) to seperate h/m/s.")
                invalid = True
                break

        if invalid: continue
        elif (offset[2] in ["6","7","8","9"]) or (offset[5] in ["6","7","8","9"]):
            print("\nInvalid! Minutes and seconds must not exceed 59.")
            continue
        else: break

    if sign == "+":
        return filename, convert(offset, 'to seconds')
    return filename, convert("-"+offset, 'to seconds')

#__________________________________________________________________________________________________________

def fix(line, offset):

    if not line:
        print()
        return line # Dealing with an empty line.

    line += ' ' # Marks end of line.

    index = 0
    next = 0
    text = ""
    flag = False
    to_fix = {}

    count = 1
    # Checking each character in the line.
    for i in range(len(line)-1): # Using range, so I can also index the end of the timestamp.

        if i < next: continue # Skips to end of timestamp, if previously found.
        elif i == next and text != "":
            text += line[i]

        next = i


        try:

            # DETECTING A NUMBER, INDICATIVE OF A TIMESTAMP
            if line[i] in numbers and line[i+7] not in numbers:

            # Testing for false positives ___________________________
                if line[i+1] != ':' or line [i+4] != ':':
                    text += line[i]
                    continue
            #________________________________________________________

                if text != "": # Avoids adding it at the beginning of the line.
                    to_fix[str(count)] = text # Example: {"2", " - Game name (Trailer:"}
                    text = "" # Reset
                    count += 1

                to_fix[str(count)] = line[i:i+7] # Example: "1":"1:45:02"}
                count += 1
                next = i+7

            else: text += line[i] # Storing the text parts character by character.

        except IndexError: text += line[i]

        to_fix[str(count)] = text

    #print(to_fix)

    line = ""
    for key in to_fix:
        try:
            if to_fix[key][0] in numbers:
                ts_inSeconds = convert(to_fix[key],"to seconds")
                to_fix[key] = convert(ts_inSeconds + offset, "to h:m:s")
        except: pass
        line += to_fix[key]

    print(line) # Output to console.
    return line


#__________________________________________________________________________________________________________


def start():

    filename, offset = query()
    print(f"\nOffsetting by {offset}s...\n\n")

    with open((filename + ".txt"), 'r', encoding="utf-8") as f:
        lines = f.readlines()

    #print(lines)
    newlines = []

    count = 0
    for line in lines:
      count += 1
      with open((filename + "_new.txt"), 'a', encoding="utf-8") as new:
        new.write(fix( line.strip(), offset) +'\n')
#__________________________________________________________________________________________________________

if __name__ == "__main__":
    start()