package report

import (
	"fmt"
	"time"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
)

func weekendDefinition() Definition {
	return Definition{
		ID:                 Weekend,
		Name:               "Weekend Outlook",
		PromptID:           "weather.weekend_outlook",
		GenerationMode:     GenerationModeScriptoriumMarkdown,
		ComparisonStrategy: CompareWeekendWindow,
		ArtifactGroup:      "weekend",
		BatchOutputName:    "weekend.md",
		DistributorPathTemplates: []string{
			"weekend/{valid_start_date}/{run_id}.md",
			"weekend/{valid_start_date}/index.md",
		},
		Generated:          true,
		CompatiblePriorIDs: []ID{Weekend},
		Modules:            weekendModules(),
		Morning:            true,
		resolve:            resolveWeekend,
	}
}

func weekendModules() []module.ConfigItem {
	return moduleItems(
		module.Metadata,
		module.CurrentConditions,
		module.DerivedDaypartSummaries,
		module.PrecipTiming,
		module.AlertDigest,
		module.SPCConvectiveOutlooks,
		module.AreaForecastDiscussion,
		module.SPCConvectiveDiscussion,
		module.WeatherStory,
		module.OutdoorWindows,
	)
}

func resolveWeekend(req ResolveRequest) (timeutil.Period, error) {
	localNow := req.Now.In(req.Location)
	weekday := localNow.Weekday()
	if weekday == time.Sunday {
		return timeutil.Period{}, fmt.Errorf("weekend outlook is not scheduled on Sunday morning")
	}

	daysUntilSaturday := (int(time.Saturday) - int(weekday) + 7) % 7
	saturday := localNow.AddDate(0, 0, daysUntilSaturday)
	start := time.Date(saturday.Year(), saturday.Month(), saturday.Day(), 0, 0, 0, 0, req.Location)
	if weekday == time.Friday || weekday == time.Saturday {
		friday := start.AddDate(0, 0, -1)
		fridayEvening := time.Date(friday.Year(), friday.Month(), friday.Day(), 18, 0, 0, 0, req.Location)
		start = fridayEvening
		if localNow.After(start) {
			start = localNow
		}
	}
	end := time.Date(saturday.Year(), saturday.Month(), saturday.Day(), 0, 0, 0, 0, req.Location).AddDate(0, 0, 2)
	return timeutil.Period{Start: start, End: end}, nil
}