package plonky2_verifier

import (
	. "gnark-plonky2-verifier/field"
)

type gate interface {
	EvalUnfiltered(vars EvaluationVars) []QuadraticExtension
}

func (p *PlonkChip) computeFilter(
	row int,
	groupRange Range,
	s QuadraticExtension,
	manySelector bool,
) QuadraticExtension {
	product := p.qeAPI.ONE_QE
	for i := groupRange.start; i < groupRange.end; i++ {
		if i == uint64(row) {
			continue
		}

		product = p.qeAPI.MulExtension(product, p.qeAPI.SubExtension(p.qeAPI.FieldToQE(NewFieldElement(i)), s))
	}

	if manySelector {
		product = p.qeAPI.MulExtension(product, p.qeAPI.SubExtension(p.qeAPI.FieldToQE(NewFieldElement(UNUSED_SELECTOR)), s))
	}

	return product
}

func (p *PlonkChip) evalFiltered(
	g gate,
	vars EvaluationVars,
	row int,
	selectorIndex int,
	groupRange Range,
	numSelectors int,
) []QuadraticExtension {
	filter := p.computeFilter(row, groupRange, vars.localConstants[selectorIndex], numSelectors > 1)

	vars.RemovePrefix(numSelectors)

	unfiltered := g.EvalUnfiltered(vars)
	for i := range unfiltered {
		unfiltered[i] = p.qeAPI.MulExtension(unfiltered[i], filter)
	}
	return unfiltered
}