import {createByConstraintName} from "./solverConstraints";
import {Param, prepare} from "./solver";
import {findConstructionCluster} from "./constructions";
import {GCCircle, GCPoint} from "./constractibles";
import {eqEps, eqTol} from "../../brep/geom/tolerance";
import {Polynomial, POW_1_FN} from "./polynomial";
import {compositeFn, NOOP} from "../../../../modules/gems/func";

export class AlgNumSubSystem {


  generator = NOOP;//new BoundaryObjectsGenerator();

  constraints = [];

  ownParams = new Set();

  readOnlyParams = new Set();

  generatedParams = new Set();

  beingSolvedParams = new Set();


  // generators = [];
  subSystems = []; //subsystems are generated by generators only

  polynomials = [];
  substitutedParams = [];
  polyToConstr = new Map();
  conflicting = new Set();
  redundant  = new Set();

  SubSystem(generator) {
    this.generator = generator;
  }

  addConstraint(constraint, _ancestorParams) {

    if (this.canBeAdded(constraint.params)) {
      // this.constraints.push(constraint);
      // this.constraints
    }

    this.constraints.push(constraint);
  }

  reset() {
    this.polynomials = [];
    this.substitutedParams = [];
    this.polyToConstr.clear();
    this.conflicting.clear();
    this.redundant.clear();
    this.beingSolvedParams.clear();
  }

  evaluatePolynomials() {
    this.constraints.forEach(c => {
      c.collectPolynomials(this.polynomials);
      this.polynomials.forEach(p => this.polyToConstr.set(p, c))
    });

    console.log('reducing system:');
    this.polynomials.forEach(p => console.log(p.toString()));

    const toEliminate = Array.from(this.readOnlyParams);

    const toSubstitute = [];
    const linearSub = [];

    let requirePass = true;

    while (requirePass) {
      requirePass = false;
      for (let i = 0; i < this.polynomials.length; ++i) {
        const polynomial = this.polynomials[i];
        if (!polynomial) {
          continue;
        }

        if (polynomial.monomials.length === 0) {
          if (!eqEps(polynomial.constant, 0)) {
            this.conflicting.add(this.polyToConstr.get(polynomial));
          }
          this.polynomials[i] = null;
        } else if (polynomial.monomials.length === 1) {
          const monomial = polynomial.monomials[0];
          const terms = monomial.terms;
          if (terms.length === 1) {
            const term = terms[0];
            if (term.fn.degree === 1) {
              term.param.set(- polynomial.constant / monomial.constant);
              toEliminate.push(term.param);
            }
          }

          this.polynomials[i] = null;
        } else if (polynomial.monomials.length === 2 && polynomial.isLinear) {
          const [m1, m2] = polynomial.monomials;

          const constant = - m2.constant / m1.constant;
          if (eqEps(polynomial.constant, 0)) {
            toSubstitute.push([m1.linearParam, m2.linearParam, constant]);
            this.substitutedParams.push([m1.linearParam, new Polynomial().monomial(constant).term(m2.linearParam, POW_1_FN)]);
          } else {
            linearSub.push([m1.param, m2.param, constant, - polynomial.constant / m1.constant]);
          }
          this.polynomials[i] = null;
        }
      }

      while (toEliminate.length) {
        requirePass = true;
        const param = toEliminate.pop();
        for (let polynomial of this.polynomials) {
          if (polynomial) {
            polynomial.eliminate(param, param.get());
          }
        }
      }
      while (toSubstitute.length) {
        requirePass = true;
        const [param, toParam, dotConstant] = toSubstitute.pop();
        for (let polynomial of this.polynomials) {
          if (polynomial) {
            polynomial.substitute(param, toParam, dotConstant);
          }
        }
      }

      if (linearSub.length) {
        while (linearSub.length) {
          const [param, toParam, k, b] = linearSub.pop();

          let transaction = compositeFn();
          for (let polynomial of this.polynomials) {
            if (polynomial) {
              const polyTransaction = polynomial.linearSubstitution(param, toParam, k, b);
              if (!polyTransaction) {
                transaction = null;
                break;
              }
              transaction.push(polyTransaction);
              transaction.push(() => this.substitutedParams.push(param, new Polynomial(b).monomial(k).term(toParam, POW_1_FN)));
            }
          }
          if (transaction) {
            requirePass = true;
            transaction();
          }
        }
      }

      if (requirePass) {
        this.polynomials.forEach(polynomial => polynomial && polynomial.compact());
      }
    }


    this.polynomials = this.polynomials.filter(p => p);

  }


  prepare() {

    this.reset();

    this.evaluatePolynomials();

    console.log('solving system:');
    this.polynomials.forEach(p => console.log(p.toString()));
    console.log('with respect to:');
    this.substitutedParams.forEach(([x, expr]) => console.log('X' + x.id  + ' = ' + expr.toString()));


    const residuals = [];

    this.polynomials.forEach(p => residuals.push(p.asResidual()));

    for (let residual of residuals) {
      residual.params.forEach(solverParam => {
        if (!this.beingSolvedParams.has(solverParam)) {
          solverParam.reset(solverParam.objectParam.get());
          this.beingSolvedParams.add(solverParam);
        }
      });
    }
    this.numericalSolver = prepare(residuals);
  }


  solve(rough) {
    this.generator();

    this.beingSolvedParams.forEach(solverParam => {
      solverParam.set(solverParam.objectParam.get());
    });

    this.numericalSolver.solveSystem(rough);

    this.beingSolvedParams.forEach(solverParam => {
      solverParam.objectParam.set(solverParam.get());
    });
    for (let i = this.substitutedParams.length - 1; i >= 0; i--) {
      let [param, expression] = this.substitutedParams[i];
      param.set(expression.value());
    }
  }



  canBeAdded(subjectParams, ancestorParams) {

    for (let p of subjectParams) {
      if (!this.ownParams.has(p) && (!ancestorParams || !ancestorParams.has(p))) {
        return false;
      }
    }

    return true;
  }
}


export class AlgNumSystem {
  constraints = [];
  generators = [];
  locked = new Set();
  constantParams = new Set();

  constructor(visitAllObjects) {
    this.visitAllObjects = visitAllObjects;
  }

  addConstraint(constraint) {
    this.constraints.push(constraint);
    if (constraint.schema.generator) {

    }
  }

  startTransaction(interactiveLock = []) {
    this.systemTransaction.prepare(interactiveLock);
    return this.systemTransaction;
  }
}