package generatedtext

import (
	"fmt"
	"strings"
)

type dayStyleFields struct {
	Summary             string
	ForecastDiscussion  []string
	PrecipitationTiming string
	Confidence          string
}

type dayStyleGeneratedText interface {
	dayStyleFields() dayStyleFields
	setDayStyleFields(dayStyleFields)
}

func validateDayStyleGeneratedText[T any, PT interface {
	*T
	dayStyleGeneratedText
}](data []byte, name string) (T, []byte, error) {
	value, err := decodeGeneratedText[T](data, name)
	if err != nil {
		var zero T
		return zero, nil, err
	}

	pointer := PT(&value)
	fields := pointer.dayStyleFields()
	fields.Summary = strings.TrimSpace(fields.Summary)
	fields.PrecipitationTiming = strings.TrimSpace(fields.PrecipitationTiming)
	fields.Confidence = strings.TrimSpace(fields.Confidence)
	fields.ForecastDiscussion = trimNonEmpty(fields.ForecastDiscussion)
	if fields.Summary == "" {
		var zero T
		return zero, nil, fmt.Errorf("%s generated text summary is required", name)
	}
	if len(fields.ForecastDiscussion) == 0 {
		var zero T
		return zero, nil, fmt.Errorf("%s generated text forecast discussion is required", name)
	}
	pointer.setDayStyleFields(fields)

	normalized, err := normalizeGeneratedText(value, name)
	if err != nil {
		var zero T
		return zero, nil, err
	}
	return value, normalized, nil
}

func trimNonEmpty(values []string) []string {
	out := make([]string, 0, len(values))
	for _, value := range values {
		trimmed := strings.TrimSpace(value)
		if trimmed != "" {
			out = append(out, trimmed)
		}
	}
	return out
}