import * as plugins from './smartrule.plugins';
import { Rule, TCheckFunc, TActionFunc, TTreeActionResult } from './smartrule.classes.rule';

export class SmartRule<T> {
  public rules: Array<Rule<T>> = [];

  /**
   * makes a decision based on the given obect and the given rules
   * @param objectArg 
   */
  public async makeDecision(objectArg: T) {
    // lets sort the rules
    this.rules = this.rules.sort((a,b) => {
      if (a.priority > b.priority) {
        return 1;
      } else {
        return 0;
      }
    });

    // gets the next batch with the same priority
    const getNextParallelBatch = (priorityStart: number) => {
      return this.rules.filter(rule => {
        return rule.priority === priorityStart;
      });
    };

    // lets run the checks
    const runNextBatch = async (startPriority: number, runRulesAmount: number): Promise<void> => {
      const nextBatch = getNextParallelBatch(startPriority);
      runRulesAmount = runRulesAmount + nextBatch.length;
      const outcomes: TTreeActionResult[] = [];
      for (const rule of nextBatch) {
        const checkResult = await rule.checkFunction(objectArg);
        if (checkResult.startsWith("apply")) {
          await rule.actionFunction(objectArg); // here the action function is run
        }
        outcomes.push(checkResult);
      }

      if (outcomes.length > 0) {
        const finalOutcomeOfBatch: TTreeActionResult = outcomes.reduce((previous, current, index, array) => {
          if (current.includes('continue') || previous.includes('continue')) {
            return 'continue';
          } else {
            return 'stop';
          }
        });
        if (finalOutcomeOfBatch === 'stop') {
          return;
        }
      }

      if (runRulesAmount < this.rules.length) {
        await runNextBatch((startPriority + 1), runRulesAmount);
      } else {
        return;
      }
    };

    await runNextBatch(0,0);
  }

  public createRule(priorityArg: number, checkFunctionArg: TCheckFunc<T>, actionFunctionArg: TActionFunc) {
    const rule = new Rule<T>(this, priorityArg, checkFunctionArg, actionFunctionArg);
    this.rules.push(rule);
  }
}