#!/usr/bin/env python3
"""Isolated UDP SIP UAC/UAS on test B. No PSTN routing or remote targets."""
import json
import re
import socket
import threading
import time
import uuid

events = []
stop = threading.Event()

def header(message, name):
    match = re.search(r'^' + re.escape(name) + r':\s*(.+)$', message, re.I | re.M)
    return match.group(1).strip() if match else ''

def reply(message, code, reason):
    to = header(message, 'To')
    if ';tag=' not in to:
        to += ';tag=cra-uas'
    vias = re.findall(r'^Via:\s*(.+)$', message, re.I | re.M)
    routes = re.findall(r'^Record-Route:\s*(.+)$', message, re.I | re.M)
    lines = [f'SIP/2.0 {code} {reason}'] + [f'Via: {v.strip()}' for v in vias]
    lines += [f'From: {header(message,"From")}', f'To: {to}', f'Call-ID: {header(message,"Call-ID")}', f'CSeq: {header(message,"CSeq")}']
    lines += [f'Record-Route: {r.strip()}' for r in routes]
    lines += ['Contact: <sip:uas@127.0.0.1:50630>', 'Content-Length: 0', '', '']
    return '\r\n'.join(lines).encode()

def uas():
    with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
        sock.bind(('127.0.0.1',50630)); sock.settimeout(.2)
        while not stop.is_set():
            try: data, addr = sock.recvfrom(65535)
            except socket.timeout: continue
            msg = data.decode(); method = msg.split()[0]
            if method == 'INVITE':
                number = re.search(r'INVITE sip:([^@]+)',msg).group(1)
                cases = {'99101':[(180,'Ringing'),(486,'Busy Here')], '99102':[(183,'Session Progress'),(487,'Request Terminated')], '99103':[(486,'Busy Here')], '99104':[(200,'OK')], '99105':[(180,'Ringing'),(200,'OK')], '99106':[(100,'Trying'),(486,'Busy Here')]}
                for code, reason in cases[number]:
                    sock.sendto(reply(msg,code,reason),addr)
                    events.append({'callId':header(msg,'Call-ID'),'direction':'UAS','code':code,'time':time.time()})
                    time.sleep(.15 if number!='99106' else 1.5)
            elif method == 'BYE': sock.sendto(reply(msg,200,'OK'),addr)

thread = threading.Thread(target=uas,daemon=True); thread.start(); time.sleep(.3)
try:
    for number in ['99101','99102','99103','99104','99105','99106']:
        with socket.socket(socket.AF_INET,socket.SOCK_DGRAM) as sock:
            sock.bind(('127.0.0.1',0)); sock.settimeout(8); port=sock.getsockname()[1]
            callid=f'cra-{number}-{uuid.uuid4().hex}@loopback'; tag=uuid.uuid4().hex[:8]
            branch='z9hG4bK'+uuid.uuid4().hex
            base=[f'Via: SIP/2.0/UDP 127.0.0.1:{port};branch={branch};rport', f'From: <sip:99100001@127.0.0.1>;tag={tag}', f'To: <sip:{number}@127.0.0.1>', f'Call-ID: {callid}', f'Contact: <sip:99100001@127.0.0.1:{port}>', 'Max-Forwards: 70']
            invite='\r\n'.join([f'INVITE sip:{number}@127.0.0.1:15060 SIP/2.0',*base,'CSeq: 1 INVITE','Content-Length: 0','',''])
            sock.sendto(invite.encode(),('127.0.0.1',15060))
            while True:
                msg=sock.recv(65535).decode(); code=int(msg.split()[1]); events.append({'callId':callid,'direction':'UAC','code':code,'time':time.time()})
                if code<200: continue
                if code>=300:
                    ack=invite.replace('INVITE sip:','ACK sip:',1).replace('CSeq: 1 INVITE','CSeq: 1 ACK').replace(base[2],f'To: {header(msg,"To")}')
                    sock.sendto(ack.encode(),('127.0.0.1',15060)); break
                routes = list(reversed(re.findall(r'^Record-Route:\s*(.+)$',msg,re.I|re.M)))
                for method,cseq in [('ACK',1),('BYE',2)]:
                    if method=='BYE': time.sleep(.3 if number=='99105' else 1.5)
                    seq=[f'{method} sip:uas@127.0.0.1:50630 SIP/2.0',f'Via: SIP/2.0/UDP 127.0.0.1:{port};branch=z9hG4bK{uuid.uuid4().hex};rport',base[1],f'To: {header(msg,"To")}',base[3],*['Route: '+r.strip() for r in routes],f'CSeq: {cseq} {method}','Max-Forwards: 70','Content-Length: 0','','']
                    sock.sendto('\r\n'.join(seq).encode(),('127.0.0.1',15060))
                    if method=='BYE':
                        final=sock.recv(65535).decode(); assert final.startswith('SIP/2.0 200'), final
                break
        time.sleep(.3)
finally:
    stop.set(); thread.join(timeout=2)
print(json.dumps(events))