package grow

import "github.com/firestuff/subcoding/gen"
import "github.com/firestuff/subcoding/vm"

func (def *Definition) Grow(statusChan chan<- Status) (*vm.Program, error) {
	status := Status{
		TargetScore: uint64(len(def.Samples)),
	}

	if statusChan != nil {
		statusChan <- status
	}

	// TODO: Score should be number of output criteria, not number of Samples
	for {
		status.Attempts++

		prog := gen.RandProgram(def.GlobalMemorySize, def.FunctionMemorySize, def.InstructionLimit)

		score, err := def.Score(prog)
		if err != nil {
			close(statusChan)
			return nil, err
		}

		if score > status.BestScore {
			status.BestScore = score
			status.BestProgram = prog

			if statusChan != nil {
				statusChan <- status
			}

			if status.BestScore == status.TargetScore {
				close(statusChan)
				return prog, nil
			}
		}
	}
}

func (def *Definition) Score(prog *vm.Program) (uint64, error) {
	score := uint64(0)

	for _, sample := range def.Samples {
		state, err := vm.NewState(prog)
		if err != nil {
			return 0, err
		}

		sample.SetInputs(state)

		state.Execute() // ignore error

		if sample.OutputsMatch(state) {
			score += 1
		}
	}

	return score, nil
}