/** Phase 0 executable contract model for XZBT 0.1 GC5. */

export const DISPATCH_BUDGET = 1024;
export const TERMINATION_HOOK_LIMIT = 256;
export const CLEANUP_TICKS = 5 * 60;

export class ConditionTrigger {
  constructor(holdTicks = 0) {
    this.holdTicks = holdTicks;
    this.armed = false;
    this.trueTicks = 0;
  }

  evaluate(value) {
    if (!value) {
      this.armed = true;
      this.trueTicks = 0;
      return false;
    }
    if (!this.armed) return false;
    this.trueTicks++;
    if (this.trueTicks < Math.max(1, this.holdTicks)) return false;
    this.armed = false;
    this.trueTicks = 0;
    return true;
  }
}

export class DeferredStartQueue {
  constructor(defaultExpiryTicks = 5 * 60 * 60) {
    this.defaultExpiryTicks = defaultExpiryTicks;
    this.requests = new Map();
  }

  defer({ definitionId, priority = 50, creationTick, documentOrder, expiryTicks, sampledInputs }) {
    if (this.requests.has(definitionId)) return false;
    this.requests.set(definitionId, {
      definitionId,
      priority,
      creationTick,
      documentOrder,
      expiresAt: creationTick + (expiryTicks ?? this.defaultExpiryTicks),
      sampledInputs
    });
    return true;
  }

  dispatch(tick, isEligible) {
    for (const [id, request] of this.requests) {
      if (tick >= request.expiresAt) this.requests.delete(id);
    }
    const ordered = [...this.requests.values()].sort((left, right) =>
      right.priority - left.priority || left.creationTick - right.creationTick || left.documentOrder - right.documentOrder
    );
    const started = [];
    for (const request of ordered) {
      if (!isEligible(request)) continue;
      started.push(request);
      this.requests.delete(request.definitionId);
    }
    return started;
  }
}

export function drainDispatch(initialQueue, expand, budget = DISPATCH_BUDGET) {
  const queue = [...initialQueue];
  const processed = [];
  let consumed = 0;
  while (queue.length > 0 && consumed < budget) {
    const unit = queue.shift();
    consumed++;
    processed.push(unit);
    const added = expand(unit) || [];
    queue.push(...added);
  }
  return {
    processed,
    consumed,
    exhausted: queue.length > 0,
    discarded: queue,
    failedOwnerIds: [...new Set(queue.map((unit) => unit.ownerId).filter(Boolean))]
  };
}

export class OwnershipModel {
  constructor() {
    this.tickIndex = 0;
    this.state = new Map();
    this.owners = new Map();
    this.resources = new Map();
    this.diagnostics = [];
    this.nextResourceId = 1;
  }

  startScenario(id, { onStart = [], onComplete = [], onCancel = [] } = {}) {
    const owner = { id, status: 'STARTING', blocked: false, onComplete, onCancel, terminalCause: null };
    this.owners.set(id, owner);
    const succeeded = this.executeActions(onStart, id, 'ordinary');
    if (succeeded) owner.status = 'ACTIVE';
    return owner;
  }

  executeActions(actions, ownerId, phase = 'ordinary') {
    const owner = this.owners.get(ownerId);
    for (let index = 0; index < actions.length; index++) {
      const action = actions[index];
      if (phase === 'ordinary' && owner?.blocked) return false;
      try {
        if (phase === 'termination' && !['set', 'sound', 'fail'].includes(action.type)) {
          throw new Error(`Action '${action.type}' is not permitted in a termination hook.`);
        }
        if (action.type === 'set') {
          this.state.set(action.target, action.value);
        } else if (action.type === 'sound') {
          if (action.continuous || action.ownership === 'persistent') {
            throw new Error('Termination hooks permit only nonpersistent one-shot sounds.');
          }
          this.createResource(ownerId, { kind: 'termination-sound', releaseTicks: action.releaseTicks ?? 0 });
        } else if (action.type === 'resource') {
          this.createResource(ownerId, action);
        } else if (action.type === 'event') {
          if (!this.executeActions(action.actions || [], ownerId, phase)) return false;
        } else if (action.type === 'fail') {
          throw new Error(action.message || 'injected failure');
        }
      } catch (error) {
        this.diagnostics.push({ code: 'ERR_ACTION_FAILURE', ownerId, phase, index, message: error.message });
        if (phase === 'termination') continue;
        if (action.critical) {
          this.terminate(ownerId, 'failure');
          return false;
        }
      }
    }
    return true;
  }

  createResource(ownerId, { kind = 'generic', releaseTicks = 0, ownership = 'scenario' } = {}) {
    const effectiveOwner = ownership === 'persistent' ? 'performance' : ownerId;
    const id = `resource-${this.nextResourceId++}`;
    this.resources.set(id, { id, kind, ownerId: effectiveOwner, releaseTicks, cleanupAt: null });
    return id;
  }

  terminate(ownerId, cause) {
    const owner = this.owners.get(ownerId);
    if (!owner || owner.blocked) return;
    owner.blocked = true;
    owner.terminalCause = cause;
    const hook = cause === 'complete' ? owner.onComplete : owner.onCancel;
    this.executeActions(hook.slice(0, TERMINATION_HOOK_LIMIT), ownerId, 'termination');
    if (hook.length > TERMINATION_HOOK_LIMIT) {
      this.diagnostics.push({ code: 'ERR_DISPATCH_BUDGET', ownerId, phase: 'termination' });
    }

    for (const resource of this.resources.values()) {
      if (resource.ownerId !== ownerId) continue;
      const boundedRelease = Math.min(resource.releaseTicks, CLEANUP_TICKS);
      if (boundedRelease === 0) this.resources.delete(resource.id);
      else {
        resource.ownerId = `cleanup:${ownerId}`;
        resource.cleanupAt = this.tickIndex + boundedRelease;
        resource.forceAt = this.tickIndex + CLEANUP_TICKS;
        resource.forceRequired = resource.releaseTicks > CLEANUP_TICKS;
      }
    }
    owner.status = cause === 'complete' ? 'COMPLETED' : cause === 'failure' ? 'FAILED' : 'CANCELLED';
  }

  tick(count = 1) {
    for (let step = 0; step < count; step++) {
      this.tickIndex++;
      for (const resource of [...this.resources.values()]) {
        if (!resource.cleanupAt || this.tickIndex < resource.cleanupAt) continue;
        if (resource.forceRequired && this.tickIndex >= resource.forceAt) {
          this.diagnostics.push({ code: 'WARN_CLEANUP_FORCED', resourceId: resource.id });
        }
        this.resources.delete(resource.id);
      }
    }
  }

  ownedResourceCount(ownerId) {
    return [...this.resources.values()].filter((resource) => resource.ownerId === ownerId).length;
  }
}