package net.ciklum.icfpc11.plan

import net.ciklum.icfpc11.domain.Card

/**
 * blabla
 * @author vic
 */
@Typed
final class ConstantCommandPlanner {

    /**
     * Get a Card to reach target constant from a given constant.
     * FIXME: Duplicates FunctionTreeBuilder.n() somewhat
     * @param target
     * @param slot
     * @param current
     * @return null if target can't be obtained from current value
     */
    Card nextCardToObtainConstant(int target, int current) {
        if (target == current) return null

        List <ConstantPlanner.Constant> path = ConstantPlanner.instance.findPath(target)
        int index = path.findIndexOf { ConstantPlanner.Constant it -> it.value == current }

        if (index < 0) return null // no way to reach that constant
        switch (path[index+1].obtainedBy) {
            case ConstantPlanner.Operation.DBL: return Card.dbl
            case ConstantPlanner.Operation.SUCC: return Card.succ
            default:
                throw new RuntimeException('unexpected constant operation')
        }
    }

    // FIXME: TEST ME
    int stepsToReach(int target, int current) {
        List <ConstantPlanner.Constant> path = ConstantPlanner.instance.findPath(target)
        int index = path.findIndexOf { ConstantPlanner.Constant it -> it.value == current }

        if (index < 0) return path.size() + 1
        return path.size() - index
    }
}