package nws

import (
	"context"
	"fmt"
	"strings"
	"time"

	"gitea.maximumdirect.net/ejr/feedkit/event"
	normcommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/normalizers/common"
	nwscommon "gitea.maximumdirect.net/ejr/weatherfeeder/internal/providers/nws"
	"gitea.maximumdirect.net/ejr/weatherfeeder/model"
	"gitea.maximumdirect.net/ejr/weatherfeeder/standards"
)

// WeatherStoriesNormalizer converts:
//
//	standards.SchemaRawNWSWeatherStoriesV1 -> standards.SchemaWeatherStoryV1
//
// It maps the NWS /weatherstories JSON response into a canonical story snapshot.
type WeatherStoriesNormalizer struct{}

func (WeatherStoriesNormalizer) Match(e event.Event) bool {
	return strings.TrimSpace(e.Schema) == standards.SchemaRawNWSWeatherStoriesV1
}

func (WeatherStoriesNormalizer) Normalize(ctx context.Context, in event.Event) (*event.Event, error) {
	_ = ctx

	fallbackAsOf := in.EmittedAt.UTC()
	if in.EffectiveAt != nil && !in.EffectiveAt.IsZero() {
		fallbackAsOf = in.EffectiveAt.UTC()
	}

	return normcommon.NormalizeJSON(
		in,
		"nws weatherstories",
		standards.SchemaWeatherStoryV1,
		func(parsed nwsWeatherStoriesResponse) (model.WeatherStoryRun, time.Time, error) {
			return buildWeatherStories(parsed, fallbackAsOf)
		},
	)
}

func buildWeatherStories(parsed nwsWeatherStoriesResponse, fallbackAsOf time.Time) (model.WeatherStoryRun, time.Time, error) {
	stories := make([]model.WeatherStory, 0, len(parsed.Stories))

	var officeID string
	var asOf time.Time
	for i, raw := range parsed.Stories {
		startTime, err := parseRequiredNWSTime(raw.StartTime, fmt.Sprintf("stories[%d].startTime", i))
		if err != nil {
			return model.WeatherStoryRun{}, time.Time{}, err
		}
		endTime, err := parseRequiredNWSTime(raw.EndTime, fmt.Sprintf("stories[%d].endTime", i))
		if err != nil {
			return model.WeatherStoryRun{}, time.Time{}, err
		}
		updatedAt, err := parseRequiredNWSTime(raw.UpdateTime, fmt.Sprintf("stories[%d].updateTime", i))
		if err != nil {
			return model.WeatherStoryRun{}, time.Time{}, err
		}

		storyOfficeID := strings.TrimSpace(raw.OfficeID)
		if officeID == "" && storyOfficeID != "" {
			officeID = storyOfficeID
		}
		if asOf.IsZero() || updatedAt.After(asOf) {
			asOf = updatedAt
		}

		stories = append(stories, model.WeatherStory{
			OfficeID:    storyOfficeID,
			StartTime:   startTime,
			EndTime:     endTime,
			UpdatedAt:   updatedAt,
			Title:       strings.TrimSpace(raw.Title),
			Description: strings.TrimSpace(raw.Description),
			AltText:     strings.TrimSpace(raw.AltText),
			Priority:    raw.Priority,
			Order:       raw.Order,
			DownloadURL: strings.TrimSpace(raw.Download),
		})
	}

	if asOf.IsZero() {
		asOf = fallbackAsOf.UTC()
	}

	run := model.WeatherStoryRun{
		OfficeID: officeID,
		AsOf:     asOf,
		Stories:  stories,
	}
	return run, asOf, nil
}

func parseRequiredNWSTime(raw, field string) (time.Time, error) {
	if strings.TrimSpace(raw) == "" {
		return time.Time{}, fmt.Errorf("%s is required", field)
	}
	t, err := nwscommon.ParseTime(raw)
	if err != nil {
		return time.Time{}, fmt.Errorf("%s: %w", field, err)
	}
	return t.UTC(), nil
}