# In this exercise, we will parse a format that is based on rfc 822 headers,
# though our implementation will only handle the simplest cases. The format
# looks like this:

# From: Petr Ročkai <xrockai@fi.muni.cz>
# To: Random X. Student <xstudent@fi.muni.cz>
# Subject: PV248

# and so on and so forth (for your convenience, the above example can be also
# found in the file `rfc822.txt`). In real e-mail (and in HTTP), each header
# entry may span multiple lines, but we will not deal with that.

# Our goal is to create a `dict` where the keys are the individual header
# fields and the corresponding values are the strings coming after the colon.
# In this iteration, assume that each header is unique.

def parse_rfc822( filename: str ) -> dict[ str, str ]:

    d = {}

    with open( filename, "r" ) as f:
        for line in f:
            parts = line.split( ": ", 1 ) # incl. the space

            # drop line endings
            if parts[1][-1] == '\n':
                parts[1] = parts[1][:-1]

            d[parts[0]] = parts[1]
    return d