#!/usr/bin/env python3
"""Patch a soothe2 PARAM value inside an RPP's base64 state block.
Usage: patchparam.py <in.rpp> <out.rpp> param=value [param=value...]
Value formatting: %16 params (depth, band freq/q/sens/balance, offset etc)
need %.16f; short params (selectivity, mix, mode, oversample, resolution,
attack, band on/balance?) use 'X.0'.  Append '!' to force %.16f, e.g.
depth=0.0! to guarantee full precision.
"""
import re, sys, base64

def fmt(val: float, force16: bool):
    if force16:
        return '%.16f' % val
    s = repr(val)
    if '.' not in s:
        s += '.0'
    if '.' in s and float(s) == int(float(s)) and len(s.rstrip('0').rstrip('.')) <= 4:
        return s.rstrip('0').rstrip('.') if '.' in s else s
    return '%.16f' % val

def main():
    src, out = sys.argv[1], sys.argv[2]
    params = {}
    for a in sys.argv[3:]:
        if a in ('-f16',):
            continue
        k, v, f16 = a.split('=', 1)[0], a.split('=', 1)[1], '!' in a
        params[k] = (float(v.rstrip('!')), f16)
    s = open(src, encoding='utf8', errors='replace').read()
    i = s.find('PpeX')
    if i < 0:
        i = s.find('VkMy')
    if i < 0:
        sys.exit('no state block found')
    j = s.find('>', i)
    if j < 0:
        sys.exit('malformed state block')
    block = s[i:j]
    raw = bytearray(base64.b64decode(block))
    txt = raw.decode('latin-1')
    n = 0
    for pm in re.finditer(r'(<PARAM id="([^"]*)" value=")[^"]*(")/>', txt):
        did = pm.group(2)
        if did in params:
            val, f16 = params[did]
            txt = txt[:pm.start()] + pm.group(1) + fmt(val, f16) + pm.group(3) + '/>' + txt[pm.end():]
            n += 1
    if n != len(params):
        print(f'warning: patched {n}/{len(params)} params')
    raw = txt.encode('latin-1')
    enc = base64.b64encode(raw).decode('ascii')
    line_start = s.rfind('\n', 0, i) + 1
    indent = s[line_start:i]
    wrapped = '\n'.join(indent + enc[i:i+128] for i in range(0, len(enc), 128))
    jline = s.rfind('\n', 0, j) + 1
    gt_indent = s[jline:j]
    s = s[:line_start] + wrapped + '\n' + gt_indent + s[j:]
    open(out, 'w', encoding='utf8').write(s)
    print(f'{out}: patched {n} params')

if __name__ == '__main__':
    main()