// Sanitized server-side AVEVA Historian ValCl context probe.
// Logs pointers, GUID bytes, token lengths, round flags, and return values only.

'use strict';

const moduleName = 'aahClientAccessPoint.exe';
const imageBase = ptr('0x00400000');
const moduleBase = Module.findBaseAddress(moduleName);

function emit(event) {
  event.timestampUtc = new Date().toISOString();
  console.log(JSON.stringify(event));
}

function addrFromVa(va) {
  if (moduleBase === null) {
    return null;
  }
  return moduleBase.add(ptr(va).sub(imageBase));
}

function safePtr(value) {
  if (value === null || value === undefined) {
    return null;
  }
  try {
    return ptr(value).toString();
  } catch (_) {
    return null;
  }
}

function readU8(pointer) {
  try {
    if (pointer.isNull()) return null;
    return pointer.readU8();
  } catch (_) {
    return null;
  }
}

function readU32(pointer) {
  try {
    if (pointer.isNull()) return null;
    return pointer.readU32();
  } catch (_) {
    return null;
  }
}

function readGuid(pointer) {
  try {
    if (pointer.isNull()) return null;
    const bytes = pointer.readByteArray(16);
    if (bytes === null) return null;
    return Array.prototype.map.call(new Uint8Array(bytes), b => ('0' + b.toString(16)).slice(-2)).join('');
  } catch (_) {
    return null;
  }
}

function readServerBufferSummary(buffer) {
  try {
    if (buffer.isNull()) {
      return { buffer: safePtr(buffer) };
    }

    const data = buffer.add(0x48).readPointer();
    const length = buffer.add(0x4c).readU32();
    let roundByte = null;
    let wrappedTokenLength = null;
    if (!data.isNull() && length >= 5) {
      roundByte = readU8(data);
      wrappedTokenLength = readU32(data.add(1));
    }

    return {
      buffer: safePtr(buffer),
      data: safePtr(data),
      length: length,
      roundByte: roundByte,
      wrappedTokenLength: wrappedTokenLength
    };
  } catch (error) {
    return {
      buffer: safePtr(buffer),
      readError: String(error)
    };
  }
}

function hook(name, va, callbacks) {
  const address = addrFromVa(va);
  if (address === null) {
    emit({ event: 'hook.error', name: name, reason: 'module-not-loaded', module: moduleName });
    return;
  }

  try {
    Interceptor.attach(address, callbacks);
    emit({ event: 'hook.installed', name: name, va: va, address: address.toString() });
  } catch (error) {
    emit({ event: 'hook.error', name: name, va: va, address: address.toString(), reason: String(error) });
  }
}

emit({
  event: 'script.loaded',
  module: moduleName,
  moduleBase: moduleBase === null ? null : moduleBase.toString()
});

hook('CServerNode.ProcessServerToken', '0x00526E00', {
  onEnter(args) {
    this.thisPtr = this.context.ecx;
    this.contextGuid = args[0];
    this.serverBuffer = args[1];
    this.continuePtr = args[2];
    this.errorPtr = args[3];
    emit({
      event: 'ProcessServerToken.enter',
      thisPtr: safePtr(this.thisPtr),
      contextGuidPtr: safePtr(this.contextGuid),
      contextGuidBytes: readGuid(this.contextGuid),
      serverBuffer: readServerBufferSummary(this.serverBuffer),
      continuePtr: safePtr(this.continuePtr),
      errorPtr: safePtr(this.errorPtr)
    });
  },
  onLeave(retval) {
    emit({
      event: 'ProcessServerToken.leave',
      retval: retval.toInt32(),
      continueValue: readU8(this.continuePtr)
    });
  }
});

hook('ContextSetup.0050FFC0', '0x0050FFC0', {
  onEnter(args) {
    this.thisPtr = this.context.ecx;
    this.contextGuid = args[0];
    emit({
      event: 'ContextSetup.enter',
      thisPtr: safePtr(this.thisPtr),
      contextGuidPtr: safePtr(this.contextGuid),
      contextGuidBytes: readGuid(this.contextGuid)
    });
  },
  onLeave(retval) {
    emit({ event: 'ContextSetup.leave', retval: retval.toInt32() });
  }
});

hook('ContextLookup.00517AB0', '0x00517AB0', {
  onEnter(args) {
    this.thisPtr = this.context.ecx;
    this.outPair = args[0];
    this.contextGuid = args[1];
    emit({
      event: 'ContextLookup.enter',
      thisPtr: safePtr(this.thisPtr),
      outPair: safePtr(this.outPair),
      contextGuidPtr: safePtr(this.contextGuid),
      contextGuidBytes: readGuid(this.contextGuid)
    });
  },
  onLeave(retval) {
    let first = null;
    let second = null;
    try {
      if (!this.outPair.isNull()) {
        first = this.outPair.readPointer();
        second = this.outPair.add(Process.pointerSize).readPointer();
      }
    } catch (_) {
      first = null;
      second = null;
    }
    emit({
      event: 'ContextLookup.leave',
      retval: safePtr(retval),
      contextObject: safePtr(first),
      contextSharedState: safePtr(second)
    });
  }
});

hook('AcquireCredentialsHelper.00505AE0', '0x00505AE0', {
  onEnter(args) {
    this.thisPtr = this.context.ecx;
    this.errorPtr = args[0];
    emit({
      event: 'AcquireCredentialsHelper.enter',
      contextObject: safePtr(this.thisPtr),
      errorPtr: safePtr(this.errorPtr)
    });
  },
  onLeave(retval) {
    emit({ event: 'AcquireCredentialsHelper.leave', retval: retval.toInt32() });
  }
});

hook('AcceptSecurityContextHelper.00505C00', '0x00505C00', {
  onEnter(args) {
    this.thisPtr = this.context.ecx;
    this.firstRound = args[0].toInt32() & 0xff;
    this.tokenLength = args[1].toUInt32();
    this.tokenPtr = args[2];
    this.continuePtr = args[3];
    this.serverCredentialPtr = args[4];
    this.errorPtr = args[5];
    emit({
      event: 'AcceptSecurityContextHelper.enter',
      contextObject: safePtr(this.thisPtr),
      firstRound: this.firstRound,
      tokenLength: this.tokenLength,
      tokenPtr: safePtr(this.tokenPtr),
      continuePtr: safePtr(this.continuePtr),
      serverCredentialPtr: safePtr(this.serverCredentialPtr),
      errorPtr: safePtr(this.errorPtr)
    });
  },
  onLeave(retval) {
    emit({
      event: 'AcceptSecurityContextHelper.leave',
      retval: retval.toInt32(),
      continueValue: readU8(this.continuePtr)
    });
  }
});