#!/usr/bin/env python3
# Part of JoeyLib, Copyright (c) 2026 Scott Duensing, under the MIT License.
# See LICENSE.md for license information.
# SPDX-License-Identifier: MIT

"""winIni.py - edit a Windows 3.x .INI file in place, CRLF line ends kept.

    winIni.py FILE OP SECTION KEY VALUE [OP SECTION KEY VALUE ...]

OP is one of:
  set   KEY=VALUE in SECTION: the first KEY line there is replaced (keys and
        sections match without regard to case), else the line is added at
        the end of the section, the section at the end of the file if it is
        not there.
  add   another KEY=VALUE line in SECTION unless that exact line is there
        already: for the keys Windows reads every line of (device= in
        [386Enh]).

Used by the installer's win311 component (installer/lib/win16.sh) to set up
Windows the way its Setup and Control Panel would, and by the win16 gates and
joey-run to name the program Windows runs as its shell.
"""

import sys

ENCODING = 'latin-1'
NEWLINE  = '\r\n'
OPS      = ('set', 'add')
GROUP    = 4


def sectionBounds(lines, section):
    # The index of SECTION's header and of the line after its last, or None.
    header = '[' + section.lower() + ']'
    for start, line in enumerate(lines):
        if line.strip().lower() == header:
            end = start + 1
            while end < len(lines) and not lines[end].lstrip().startswith('['):
                end += 1
            return start, end
    return None


def insertAtEnd(lines, start, end, line):
    # Before the blank lines that close the section.
    at = end
    while at > start + 1 and lines[at - 1].strip() == '':
        at -= 1
    lines.insert(at, line)


def keyOf(line):
    return line.split('=', 1)[0].strip().lower() if '=' in line else None


def apply(lines, op, section, key, value):
    line   = key + '=' + value
    bounds = sectionBounds(lines, section)
    if bounds is None:
        while lines and lines[-1].strip() == '':
            lines.pop()
        lines.extend(['', '[' + section + ']', line, ''])
        return
    start, end = bounds
    for i in range(start + 1, end):
        if op == 'set' and keyOf(lines[i]) == key.lower():
            lines[i] = line
            return
        if op == 'add' and lines[i].strip().lower() == line.lower():
            return
    insertAtEnd(lines, start, end, line)


def main(argv):
    if len(argv) < 2 + GROUP or (len(argv) - 2) % GROUP != 0:
        sys.exit(__doc__)
    path  = argv[1]
    lines = open(path, 'rb').read().decode(ENCODING).split(NEWLINE)
    for at in range(2, len(argv), GROUP):
        op, section, key, value = argv[at:at + GROUP]
        if op not in OPS:
            sys.exit('winIni.py: unknown op ' + op)
        apply(lines, op, section, key, value)
    open(path, 'wb').write(NEWLINE.join(lines).encode(ENCODING))


if __name__ == '__main__':
    main(sys.argv)