1 package takuzu

     2 

     3 import "fmt"

     4 

     5 // This file contains the takuzu validation error type.

     6 

     7 const (

     8 	ErrorNil = iota

     9 	ErrorDuplicate

    10 	ErrorTooManyValues

    11 	ErrorTooManyAdjacentValues

    12 )

    13 

    14 type validationError struct {

    15 	ErrorType    int

    16 	LineNumber   *int

    17 	ColumnNumber *int

    18 	CellValue    *int

    19 }

    20 

    21 func (e validationError) Error() string {

    22 	var axis string

    23 	var n int

    24 

    25 	// Currently we don't have validation errors with both

    26 	// line and column so we can get the axis:

    27 	if e.LineNumber != nil {

    28 		axis = "line"

    29 		n = *e.LineNumber

    30 	} else if e.ColumnNumber != nil {

    31 		axis = "column"

    32 		n = *e.ColumnNumber

    33 	}

    34 

    35 	switch e.ErrorType {

    36 	case ErrorNil:

    37 		return ""

    38 	case ErrorDuplicate:

    39 		if axis == "" {

    40 			return "internal validation error"

    41 		}

    42 		return fmt.Sprintf("duplicate %ss (%d)", axis, n)

    43 	case ErrorTooManyValues:

    44 		if axis == "" || e.CellValue == nil {

    45 			return "internal validation error"

    46 		}

    47 		var numberStr string

    48 		if *e.CellValue == 0 {

    49 			numberStr = "zeroes"

    50 		} else if *e.CellValue == 1 {

    51 			numberStr = "ones"

    52 		} else {

    53 			return "internal validation error"

    54 		}

    55 		return fmt.Sprintf("%s %d: too many %s", axis, n, numberStr)

    56 	case ErrorTooManyAdjacentValues:

    57 		if axis == "" || e.CellValue == nil {

    58 			return "internal validation error"

    59 		}

    60 		return fmt.Sprintf("%s %d: 3+ same values %d", axis, n, *e.CellValue)

    61 	}

    62 	return "internal validation error"

    63 }