package briefing

import (
	"fmt"

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

const defaultSPCConvectiveDiscussionMinimumSeverityRank = 3

type SPCConvectiveDiscussionModule struct {
	IncludedBecause string                          `json:"included_because"`
	Discussions     []SPCConvectiveDiscussionRecord `json:"discussions"`
}

type SPCConvectiveDiscussionRecord struct {
	Day        int    `json:"day,omitempty"`
	Headline   string `json:"headline,omitempty"`
	Summary    string `json:"summary,omitempty"`
	Discussion string `json:"discussion,omitempty"`
	UpdatedAt  string `json:"updated_at,omitempty"`
}

func buildSPCConvectiveDiscussionModule(ctx ModuleContext, _ any) (*module.Output, error) {
	if !hasSPCConvectiveDiscussionThreshold(ctx.Derived.SPCConvectiveOutlooks) {
		return nil, nil
	}
	records := spcConvectiveDiscussionRecords(ctx.Derived.SPCConvectiveOutlooks, ctx.Derived.SPCConvectiveDiscussions, ctx.Timezone)
	if len(records) == 0 {
		return nil, nil
	}
	value := SPCConvectiveDiscussionModule{
		IncludedBecause: fmt.Sprintf("severity_rank >= %d", defaultSPCConvectiveDiscussionMinimumSeverityRank),
		Discussions:     records,
	}
	return &module.Output{ID: module.SPCConvectiveDiscussion, StanzaName: string(module.SPCConvectiveDiscussion), Value: value}, nil
}

func hasSPCConvectiveDiscussionThreshold(outlooks []weatherdata.ConvectiveOutlook) bool {
	for _, outlook := range outlooks {
		if outlook.SeverityRank != nil && *outlook.SeverityRank >= defaultSPCConvectiveDiscussionMinimumSeverityRank {
			return true
		}
	}
	return false
}

func spcConvectiveDiscussionRecords(outlooks []weatherdata.ConvectiveOutlook, discussions []weatherdata.ConvectiveOutlookDiscussion, timezone string) []SPCConvectiveDiscussionRecord {
	retainedDays := map[int]struct{}{}
	for _, outlook := range outlooks {
		retainedDays[outlook.Day] = struct{}{}
	}
	records := make([]SPCConvectiveDiscussionRecord, 0, len(discussions))
	for _, discussion := range discussions {
		if _, ok := retainedDays[discussion.Day]; !ok {
			continue
		}
		if discussion.Discussion == "" {
			continue
		}
		records = append(records, SPCConvectiveDiscussionRecord{
			Day:        discussion.Day,
			Headline:   discussion.Headline,
			Summary:    discussion.Summary,
			Discussion: discussion.Discussion,
			UpdatedAt:  friendlyOptionalTime(discussion.UpdatedAt, timezone),
		})
	}
	return records
}