package sudoku

import (
	"errors"
	"fmt"

	"git.kleiax.de/homepage/field"
	"git.kleiax.de/homepage/logic"
	"git.kleiax.de/homepage/parser"
)

type Game struct {
	field  *field.Field
	solver logic.Solver
}

func New(input parser.Parser, solver logic.Solver, data []byte, fieldIndex int) (*Game, error) {
	if input == nil {
		return nil, errors.New("cannot create game: nil parser")
	}
	if err := input.Parse(data); err != nil {
		return nil, fmt.Errorf("cannot create game: %w", err)
	}
	parsedField, err := input.GetField(fieldIndex)
	if err != nil {
		return nil, fmt.Errorf("cannot create game: %w", err)
	}
	if parsedField == nil || !parsedField.IsValid() {
		return nil, fmt.Errorf("cannot create game: %w", field.ErrInvalidField)
	}
	return &Game{solver: solver, field: parsedField}, nil
}

func (g *Game) Solve() error {
	if g == nil || g.field == nil {
		return field.ErrInvalidField
	}
	if err := g.solver.InitStrategies(g.field); err != nil {
		return err
	}
	solved, err := g.solver.Run(0)
	if err != nil {
		return err
	}
	if !solved {
		return logic.ErrNoProgress
	}
	return nil
}

func (g *Game) GetField() *field.Field {
	if g == nil {
		return nil
	}
	return g.field
}