"""
Authors: Peter Mawhorter
Consulted:
Date: 2021-10-28
Purpose: CS 111 files lab exercises SOLUTION
"""


def showTop(filename):
    """
    Given a filename, prints out the top 3 lines in that file.
    """
    with open(filename, 'r') as fin:
        top3 = fin.readlines()[:3] # slice first 3

    for line in top3:
        print(line[:-1]) # trim off the newline at the end to avoid blanks


def showBottom(filename):
    """
    Given a filename, prints out the bottom 3 lines in that file.
    """
    with open(filename, 'r') as fin:
        bot3 = fin.readlines()[-3:] # slice last 3

    for line in bot3:
        print(line[:-1]) # trims the newline at the end


def listLines(filename):
    """
    Given a filename, print each line of that file, preceded by a line
    number and a space. Line numbers start from 1.
    """
    with open(filename, 'r') as fin:
        counter = 1
        for line in fin:
            print(counter, line, end='')
            # this "end=''" part means that we don't add the usual extra
            # newline, since line itself already contains a newline.
            counter += 1


def copyFile(fromFile, toFile):
    """
    Given two filenames, reads the first file, then opens the second file
    and writes a copy of the first file there.
    """
    with open(fromFile, 'r') as fin:
        data = fin.read()
    with open(toFile, 'w') as fout:
        fout.write(data)


def writeReport(data, filename):
    """
    Given a list of tuples containing strings paired with numbers,
    writes each entry to the given file on a separate line, with a colon
    and a space between the parts of the tuple.
    """
    with open(filename, 'w') as fout:
        # Multiple loop variables pull apart the tuple automatically
        for name, num in data:
            # A format string makes it easy to create our output
            fout.write(f"{name}: {num}")


def readReport(filename):
    """
    Reads data in the same format written by writeReport, returning a
    list of tuples containing strings and (floating-point) numbers.
    """
    result = []
    with open(filename, 'r') as fin:
        for line in fin:
            # Split where the ': ' is, removing it in the process
            name, numstr = line.split(": ")
            # Convert number to a float
            num = float(numstr)
            # Append to our result.
            # Note that the inner parentheses create a tuple
            result.append((name, num))

    return result


def fractionalHours(hour, minute):
    """
    Converts hour and minute integers into a fractional hours number. So
    for example, 15 hours and 30 minutes would become 15.5.
    """
    fraction = minute / 60
    return hour + fraction


def hourMinuteString(hours):
    """
    Converts a number of fractional hours into a string representing
    hours and minutes, with a colon between them. Rounds to the nearest
    minute.
    """
    hour = int(hours)
    minutes = round((hours - hour) * 60)
    # Deal with special cases
    if minutes == 60: # rounding up to 60 means we need to add an hour
        hour += 1
        minutes = "00"
    else:
        minutes = str(minutes)
        if len(minutes) == 1: # a one-digit result needs an extra 0
            minutes = '0' + minutes

    return f"{hour}:{minutes}"


def swapFiles(fileA, fileB):
    """
    Swaps the contents of two files. Have to be careful not to erase one
    before we've read both.
    """
    # Read the first file
    with open(fileA, 'r') as fin:
        dataA = fin.read()
    # Read the second file
    with open(fileB, 'r') as fin:
        dataB = fin.read()

    # Write the first file
    with open(fileA, 'w') as fout:
        fout.write(dataB)
    # Write the second file
    with open(fileB, 'w') as fout:
        fout.write(dataA)


def showCalendar(filename):
    """
    Reads in a calendar file where each line specifies an event, with
    three comma-separated parts: a name, a start time (as hours:minutes)
    and a duration (as fractional hours). Prints each events, listing
    start and end times in hours:minutes (24-hour clock).
    """
    with open(filename, 'r') as fin:
        for line in fin:
            name, start, duration = line.split(',')
            hours, minutes = start.split(':')
            # Convert to numbers
            hours = int(hours)
            minutes = int(minutes) # this works even with a leading zero
            duration = float(duration)
            # Convert to fractional hours and compute end
            startHours = fractionalHours(hours, minutes)
            endHours = startHours + duration
            # Convert to hour:minute strings and display
            startTime = hourMinuteString(startHours)
            endTime = hourMinuteString(endHours)
            print(f"{name} ({startTime}-{endTime})")


def test():
    """
    Testing code for the functions above.
    """
    # showTop('nums.txt')
    # showBottom('nums.txt')
    listLines('nums.txt')