package board

import (
	"bytes"
	"errors"
	"fmt"
	"strconv"
)

type Parser interface {
	parse(data []byte) error
	getField(i int) *Field
	getAllFields() []Field
}

type parserHelper struct {
	fields []Field
}

func (ph *parserHelper) getField(i int) *Field {
	if i < 0 || i >= len(ph.fields) {
		return &Field{}
	}
	return &ph.fields[i]
}

func (ph *parserHelper) getAllFields() []Field {
	if len(ph.fields) == 0 {
		return nil
	}
	return ph.fields
}

// https://github.com/grantm/sudoku-exchange-puzzle-bank/tree/master
type PuzzleBank struct {
	parserHelper
}

func (pb *PuzzleBank) parse(data []byte) error {

	lines := bytes.Split(data, []byte("\n"))
	for _, line := range lines {
		if len(line) == 0 { // Überspringe leere Zeile
			continue
		}

		if len(line) != 99 {
			return fmt.Errorf("Zeile hat die falsche länge. soll: 100, ist: %d", len(line))
		}

		//siehe Readme in github repo
		sha1Hash := bytes.TrimSpace(line[0:12])
		sudokuStr := string(line[13:94])
		ratingStr := string(line[96:99])
		//fmt.Println(sudokuStr)

		var rating float64
		_, err := fmt.Sscanf(ratingStr, "%f", &rating)
		if err != nil {
			return errors.New("can nor parse raiting")
		}

		field := Field{
			rows:            9,
			columns:         9,
			blockRows:       3,
			blockColumns:    3,
			blockSizeRow:    3,
			blockSizeColumn: 3,
			rating:          rating,
			sha1:            sha1Hash,
		}

		field.cells = make([][]Cell, field.rows)
		for i := range field.cells {
			field.cells[i] = make([]Cell, field.columns)
			for j := range field.cells[i] {
				number, err := strconv.Atoi(string(sudokuStr[i*9+j]))
				if err != nil {
					return fmt.Errorf("Kann Zeichen nicht in Zahl konvertieren")
				}
				field.cells[i][j].number = number
				field.cells[i][j].Pos = &Position{
					row:           i,
					column:        j,
					blockRow:      i / field.blockRows,
					blockColumn:   j / field.blockColumns,
					inBlockRow:    i % field.blockSizeRow,
					inBlockColumn: j % field.blockSizeColumn,
				}
			}
		}
		//fmt.Println(field.String())
		pb.fields = append(pb.fields, field)
	}
	return nil
}