package briefing

import (
	"fmt"
	"strings"

	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
)

type Weekend struct {
	Days           []OutlookDay            `json:"days"`
	Planning       WeekendPlanning         `json:"planning"`
	RelevantAlerts []forecast.AlertOverlap `json:"relevantAlerts,omitempty"`
	Discussion     DiscussionContext       `json:"discussion,omitempty"`
	WeatherStory   *WeatherStoryContext    `json:"weatherStory,omitempty"`
}

type WeekendPlanning struct {
	BestOutdoorWindows  []OutdoorWindow `json:"bestOutdoorWindows,omitempty"`
	WorstWeatherWindows []OutdoorWindow `json:"worstWeatherWindows,omitempty"`
	RainStormTiming     []string        `json:"rainStormTiming,omitempty"`
	ComfortConcerns     []string        `json:"comfortConcerns,omitempty"`
	UncertaintyInputs   []string        `json:"uncertaintyInputs,omitempty"`
}

func BuildWeekend(ctx BuildContext, summaries []forecast.DailySummary) (Package, error) {
	if ctx.Resolved.Definition.ID != report.Weekend {
		return Package{}, fmt.Errorf("weekend briefing requires a weekend report definition")
	}
	if len(summaries) == 0 {
		return Package{}, fmt.Errorf("weekend forecast summaries are required")
	}
	pkg := Package{
		Metadata: BuildMetadata(ctx),
		Weekend: &Weekend{
			Discussion:   buildDiscussion(summaries[0].Discussion),
			WeatherStory: buildWeatherStory(ctx.Bundle),
		},
	}
	for _, summary := range summaries {
		pkg.Weekend.Days = append(pkg.Weekend.Days, buildOutlookDay(summary))
	}
	pkg.Weekend.RelevantAlerts = collectOutlookAlerts(pkg.Weekend.Days)
	pkg.Weekend.Planning = buildWeekendPlanning(pkg.Weekend.Days, pkg.Weekend.Discussion, ctx.Bundle)
	return pkg, nil
}

func buildWeekendPlanning(days []OutlookDay, discussion DiscussionContext, bundle *forecast.Bundle) WeekendPlanning {
	planning := WeekendPlanning{}
	for _, day := range days {
		if day.OutdoorWindows.Best != nil {
			window := *day.OutdoorWindows.Best
			window.Daypart = day.Date + " " + window.Daypart
			planning.BestOutdoorWindows = append(planning.BestOutdoorWindows, window)
		}
		if day.OutdoorWindows.Worst != nil {
			window := *day.OutdoorWindows.Worst
			window.Daypart = day.Date + " " + window.Daypart
			planning.WorstWeatherWindows = append(planning.WorstWeatherWindows, window)
		}
		for _, daypart := range day.Dayparts {
			planning.RainStormTiming = appendUnique(planning.RainStormTiming, weekendRainStormNotes(day.Date, daypart)...)
			planning.ComfortConcerns = appendUnique(planning.ComfortConcerns, weekendComfortNotes(day.Date, daypart)...)
		}
	}
	planning.UncertaintyInputs = appendUnique(planning.UncertaintyInputs, discussion.KeyMessages...)
	if discussion.ShortTerm != "" {
		planning.UncertaintyInputs = appendUnique(planning.UncertaintyInputs, "Short-term discussion available for confidence context.")
	}
	if discussion.LongTerm != "" {
		planning.UncertaintyInputs = appendUnique(planning.UncertaintyInputs, "Long-term discussion available for uncertainty context.")
	}
	if bundle != nil {
		for _, warning := range bundle.Warnings {
			if warning.Code != "" {
				planning.UncertaintyInputs = appendUnique(planning.UncertaintyInputs, "Source warning: "+warning.Code+".")
			}
		}
	}
	if len(planning.RainStormTiming) == 0 {
		planning.RainStormTiming = append(planning.RainStormTiming, "No focused rain or storm timing stands out in the available weekend forecast.")
	}
	if len(planning.ComfortConcerns) == 0 {
		planning.ComfortConcerns = append(planning.ComfortConcerns, "No major heat, cold, or wind comfort concern stands out in the available weekend forecast.")
	}
	if len(planning.UncertaintyInputs) == 0 {
		planning.UncertaintyInputs = append(planning.UncertaintyInputs, "No explicit confidence or uncertainty signal was available from the selected source context.")
	}
	return planning
}

func weekendRainStormNotes(date string, daypart forecast.DaypartSummary) []string {
	notes := []string{}
	label := weekendWindowLabel(date, daypart.Name)
	if daypart.MaxPrecipitationProbability != nil && daypart.MaxPrecipitationProbability.Value >= 30 {
		notes = append(notes, fmt.Sprintf("%s precipitation chance peaks near %.0f%%.", label, daypart.MaxPrecipitationProbability.Value))
	}
	if daypart.Indicators.Thunder {
		notes = append(notes, label+" thunder risk is present.")
	}
	return notes
}

func weekendComfortNotes(date string, daypart forecast.DaypartSummary) []string {
	notes := []string{}
	label := weekendWindowLabel(date, daypart.Name)
	if daypart.Indicators.Heat {
		notes = append(notes, label+" heat may affect outdoor comfort.")
	}
	if daypart.Indicators.Cold {
		notes = append(notes, label+" cold may affect outdoor comfort.")
	}
	if daypart.PeakWindGust != nil && daypart.PeakWindGust.Value >= 25 {
		notes = append(notes, fmt.Sprintf("%s gusts may reach %.0f mph.", label, daypart.PeakWindGust.Value))
	}
	return notes
}

func weekendWindowLabel(date string, daypart string) string {
	if daypart == "" {
		return date
	}
	return strings.TrimSpace(date + " " + daypart)
}