package ocr
import (
	"strings"
)
// ocrSolver is a 3 line chunk of digits
var ocrSolver = map[string]string{
	" _ | ||_|": "0",
	"     |  |": "1",
	" _  _||_ ": "2",
	" _  _| _|": "3",
	"   |_|  |": "4",
	" _ |_  _|": "5",
	" _ |_ |_|": "6",
	" _   |  |": "7",
	" _ |_||_|": "8",
	" _ |_| _|": "9",
}
// Recognize recognizes ocr strings in input and converts to regular ones.
func Recognize(in string) []string {
	lines := strings.Split(in, "\n")
	lines = lines[1:] // drop first line, just a '\n'
	// separate input lines to 4 line long chunks to handle multiple ocr lines
	digitLines := make([][]string, (len(lines))/4)
	for i := 0; i < len(digitLines); i++ {
		digitLines[i] = make([]string, 4)
		for j := 0; j < 4; j++ {
			digitLines[i][j] = lines[4*i+j]
		}
	}
	var ret = make([]string, len(digitLines))
	for dl, dline := range digitLines {
		var ln = strings.Builder{}
		for i := 0; i < len(dline[0])/3; i++ {
			var digit strings.Builder
			// gather a digit from 3 lines pieces
			for lNo, line := range dline {
				if lNo == len(dline)-1 {
					// last line is useless
					continue
				}
				digit.WriteString(line[i*3 : i*3+3])
			}
			ln.WriteString(recognizeDigit(digit.String()))
		}
		ret[dl] = ln.String()
	}
	return ret
}
func recognizeDigit(d string) string {
	ret, ok := ocrSolver[d]
	if !ok {
		return "?"
	}
	return ret
}