Fs02/grimoire

package changeset

import (
    "strings"
)

// ValidateRequiredErrorMessage is the default error message for ValidateRequired.
var ValidateRequiredErrorMessage = "{field} is required"

// isZeroer is the interface that wraps the basic isZero method.
type isZeroer interface {
    IsZero() bool
}

// ValidateRequired validates that one or more fields are present in the changeset.
// It'll add error to changeset if field in the changes is nil or string made only of whitespace.
func ValidateRequired(ch *Changeset, fields []string, opts ...Option) {
    options := Options{
        message: ValidateRequiredErrorMessage,
    }
    options.apply(opts)

    for _, f := range fields {
        val, exist := ch.changes[f]

        // check values if it's not exist in changeset when changeOnly is false and changeset values are all zero value
        if !exist && !options.changeOnly && !ch.zero {
            val, exist = ch.values[f]
        }

        str, isStr := val.(string)
        if exist && isStr && strings.TrimSpace(str) != "" {
            continue
        }

        zeroer, isZeroer := val.(isZeroer)
        if exist && isZeroer && !zeroer.IsZero() {
            continue
        }

        // Only check nil value if val is not string and isZeroer since it has been checked before.
        if exist && !isStr && !isZeroer && val != nil {
            continue
        }

        msg := strings.Replace(options.message, "{field}", f, 1)
        AddError(ch, f, msg)
    }
}