#!/usr/bin/env python3
import base64, re, sys, os

# Reads render_v5.rpp, changes plugin PARAM values, writes a new RPP targeting an output name.

TPL = "/home/m/soothe-bt/render_v5.rpp"

def load_state(rpp=TPL):
    txt = open(rpp).read().split('\n')
    vi = [i for i,l in enumerate(txt) if 'VST "VST3: soothe2' in l][0]
    blob = []
    end = vi
    for i in range(vi+1, vi+40):
        s = txt[i].strip()
        if s == '>' or not s:
            end = i
            break
        blob.append(s)
    out = b''
    for l in blob:
        out += base64.b64decode(l + '=' * ((-len(l)) % 4))
    return txt, vi, end, blob, out

def save_state(txt, vi, end, blob, out, binary_len, rpp_out):
    # re-encode: binary_len bytes header + rest is ascii xml
    header = out[:binary_len]
    xml = out[binary_len:]
    new = base64.b64encode(header + xml).decode()
    lines = [new[i:i+128] for i in range(0, len(new), 128)]
    newblk = ['  ' + l for l in lines]
    txt2 = txt[:vi+1] + newblk + [txt[end]]
    open(rpp_out, 'w').write('\n'.join(txt2))

def set_params(rpp, out_rpp, out_wav, params):
    txt, vi, end, blob, out = load_state(rpp)
    # preserve everything: prefix before '<?xml', the xml, and the binary tail
    xml_idx = out.find(b'<?xml')
    if xml_idx < 0:
        raise ValueError("no XML in state")
    header = out[:xml_idx]
    xml_bytes = out[xml_idx:-1]  # last byte is padding
    xml = xml_bytes.decode('utf8', 'replace')
    for pid, val in params.items():
        m = re.search(rf'<PARAM id="{re.escape(pid)}" value="([^"]*)"', xml)
        if not m:
            raise ValueError(f"param not found: {pid}")
        # IMPORTANT: plugin honors the value only if serialized in the same
        # float format the original state used. depth uses full precision;
        # selectivity/mix/mode/oversample store "X.0" short form.
        # Try to keep the original format's decimal count.
        orig = m.group(1)
        if '.' in orig and len(orig.split('.')[1]) > 4:
            # full-precision param (e.g. depth) -> needs 16 decimals
            full = f"{float(val):.16f}"
        elif '.' in orig:
            # short-form param (e.g. selectivity "10.0") -> keep decimal count
            full = f"{float(val):.{len(orig.split('.')[1])}f}"
        else:
            full = val
        xml = xml[:m.start()] + f'<PARAM id="{pid}" value="{full}"' + xml[m.end():]
    if out_rpp:
        newb = base64.b64encode(header + xml.encode('utf8') + out[-1:]).decode()
        lines = [newb[i:i+128] for i in range(0, len(newb), 128)]
        txt2 = txt[:vi+1] + ['  ' + l for l in lines]
        if end < len(txt) - 1:
            txt2 = txt2 + txt[end:]
        txt2 = [l if not l.strip().startswith('RENDER_FILE')
                else f'  RENDER_FILE "{out_wav}"' for l in txt2]
        open(out_rpp, 'w').write('\n'.join(txt2))
    return txt

if __name__ == '__main__':
    # usage: sweep.py <rpp_out> <out_wav> <id=val> [id=val ...]
    rpp_out = sys.argv[1]
    out_wav = sys.argv[2]
    params = dict(a.split('=', 1) for a in sys.argv[3:])
    set_params(TPL, rpp_out, out_wav, params)
    print("wrote", rpp_out, params)