DemoCopy.ulam

local typedef BondStatus BS;

/**
   Copy non-executable package (looped) sequence, hardcoded for testing

   \symbol DC
   \color #caf7b7
 */
element DemoCopy : QStateT(3) + QBondableT(2) + QDiffusableT(100) + QMortal + Fail {
  constant QBond.Index cORIG = 0;
  constant QBond.Index cCOPY = 1;

  constant State cSTATE_ATTACH       = 0;
  constant State cSTATE_COPY         = 1;
  constant State cSTATE_ADVANCE_COPY = 2;
  constant State cSTATE_ADVANCE      = 3;
  constant State cSTATE_COMPLETE     = 4;
  constant State cSTATE_DETACH       = 5;

  @Override Void behave() {
    if (isState(cSTATE_ATTACH)) {
      attach();
    } else if (isState(cSTATE_COPY)) {
      copy();
    } else if (isState(cSTATE_ADVANCE_COPY)) {
      advanceCopy();
    } else if (isState(cSTATE_ADVANCE)) {
      advance();
    } else if (isState(cSTATE_COMPLETE)) {
      complete();
    } else if (isState(cSTATE_DETACH)) {
      detach();
    }

    if (isState(cSTATE_DONE)) {
      die();
    } else {
      diffuse();
    }
  }

  Void attach() {
    AtomUtils au;
    BondStatus bs;
    BondUtils bu;

    // Find non-exec package to attach to
    Package pkg;
    WindowServices ws;
    ws.reset(1, bu.maxDist(pkg, self));
    if (!ws.scan(au.getType(pkg)))
      return;
    SiteNum site = ws.getPick();

    if (bs.isOk(bu.attach(0, cORIG, site, Package.cCOMMON)))
      setState(cSTATE_COPY);
  }

  Void copy() {
    BondStatus bs;
    BondUtils bu;
    EventWindow ew;
    EventWindowMisc ewm;
    PackageData pd;

    QBond& origBond = getBond(cORIG);
    QBond& copyBond = getBond(cCOPY);

    // Get current package
    SiteNum origSite = origBond.getSiteNumber();
    Package& orig = (Package&) ew[origSite];
    if (orig.getBond(Package.cOTHER).isAttached()) {
      // First item
      setState(cSTATE_COMPLETE);
      return;
    }

    // Make copy
    Package pkg;
    pkg.setData(orig.getData());
    pkg.setAux(pd.resetIsActive(orig.getAux()));

    // Place around self
    SiteNum site = ewm.findEmptySite(1, bu.maxDist(self, pkg));
    if (site == SiteNum.maxof)
      return;
    ew[site] = pkg;

    if (!copyBond.isAttached()) {
      /// First item

      BS.Status status = BS.cOK;

      // Attach to self
      status = bu.attach(0, cCOPY, site, Package.cCOMMON);

      // Attach to original (marking beginning of copy)
      if (bs.isOk(status)) {
        status = bu.attach(origSite, Package.cOTHER, site, Package.cOTHER);
        if (!bs.isOk(status)) {
          // Try to detach and start over
          if (!bs.isOk(bu.detach(0, cCOPY)))
            fail("Demo_Copy.copy: failed to detach first item copy");
        }
      }

      // Cleanup on error
      if (!bs.isOk(status)) {
        Empty empty;
        ew[site] = empty;
        return;
      }

      setState(cSTATE_ADVANCE);

    } else {
      /// Attaching to previous item
      // Get current copy
      SiteNum copySite = copyBond.getSiteNumber();
      Package& copy = (Package&) ew[copySite];

      // Attach new copy package to current copy as next
      if (!bs.isOk(bu.attach(copySite, Package.cNEXT, site, Package.cPREV))) {
        Empty empty;
        ew[site] = empty;
        return;
      }

      setState(cSTATE_ADVANCE_COPY);
    }
  }

  Void advanceCopy() {
    BondStatus bs;
    BondUtils bu;

    BS.Status status = bu.traverse(0, cCOPY, Package.cNEXT);
    if (bs.isOk(status))
      setState(cSTATE_ADVANCE);
  }

  Void advance() {
    BondStatus bs;
    BondUtils bu;

    BS.Status status = bu.traverse(0, cORIG, Package.cNEXT);
    if (bs.isOk(status))
      setState(cSTATE_COPY);
  }

  Void complete() {
    BondStatus bs;
    BondUtils bu;
    EventWindow ew;

    QBond& origBond = getBond(cORIG);
    QBond& copyBond = getBond(cCOPY);
    SiteNum origSite = origBond.getSiteNumber();
    SiteNum copySite = copyBond.getSiteNumber();

    Package& orig = (Package&) ew[origSite];
    QBond& firstBond = orig.getBond(Package.cOTHER);
    SiteNum firstSite = firstBond.getSiteNumber(origSite);

    // Attach first to last, completing copy loop
    BS.Status status = bu.attach(copySite, Package.cNEXT, firstSite, Package.cPREV);
    if (bs.isOk(status))
      setState(cSTATE_DETACH);
  }

  Void detach() {
    BondStatus bs;
    BondUtils bu;

    QBond& origBond = getBond(cORIG);
    SiteNum origSite = origBond.getSiteNumber();

    BS.Status status = bu.detach(origSite, Package.cOTHER);
    if (bs.isOk(status))
      setState(cSTATE_DONE);
  }
}