package mongo

import (
	"context"
	"fmt"
	"fwh-toolbox-server/database"
	"fwh-toolbox-server/domain"
	"time"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

const (
	collectionSimCardRun        = "SimCardDailyRun"
	collectionSimCardStatistics = "SimCardDailyStatistics"
)

func InitSimCardStatisticsIndexes(ctx context.Context) error {
	_, err := database.GetCollection(CollectionName_SimCardMonthlyData).Indexes().CreateMany(ctx, []mongo.IndexModel{
		{Keys: bson.D{{Key: "month", Value: 1}, {Key: "simId", Value: 1}}},
		{Keys: bson.D{{Key: "simId", Value: 1}, {Key: "month", Value: 1}}},
	})
	return err
}

type simCardRun struct {
	SmartHubLastPage    *uint64  `bson:"smartHubLastPage"`
	AcceleronixLastPage *uint64  `bson:"acceleronixLastPage"`
	SavedPages          []string `bson:"savedPages"`
	Sent                bool     `bson:"sent"`
}

func simCardPageKey(page domain.SimCardRunPage) string {
	return fmt.Sprintf("%s:%d", page.Platform, page.Page)
}

func MarkSimCardLastPage(date string, platform domain.SimCardPlatform, page uint64) error {
	field := "smartHubLastPage"
	if platform == domain.SimPlatformAcceleronix {
		field = "acceleronixLastPage"
	}
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	_, err := database.GetCollection(collectionSimCardRun).UpdateOne(ctx, bson.M{"_id": date}, bson.M{"$set": bson.M{field: page}}, options.Update().SetUpsert(true))
	return err
}

func MarkSimCardPagesSaved(date string, pages []domain.SimCardRunPage) error {
	if len(pages) == 0 {
		return nil
	}
	keys := make([]string, 0, len(pages))
	for _, page := range pages {
		keys = append(keys, simCardPageKey(page))
	}
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	_, err := database.GetCollection(collectionSimCardRun).UpdateOne(ctx, bson.M{"_id": date}, bson.M{"$addToSet": bson.M{"savedPages": bson.M{"$each": keys}}}, options.Update().SetUpsert(true))
	return err
}

func IsSimCardRunComplete(date string) (bool, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	var run simCardRun
	err := database.GetCollection(collectionSimCardRun).FindOne(ctx, bson.M{"_id": date}).Decode(&run)
	if err == mongo.ErrNoDocuments {
		return false, nil
	}
	if err != nil {
		return false, err
	}
	return simCardRunComplete(run), nil
}

func simCardRunComplete(run simCardRun) bool {
	if run.Sent || run.SmartHubLastPage == nil || run.AcceleronixLastPage == nil {
		return false
	}
	saved := make(map[string]bool, len(run.SavedPages))
	for _, key := range run.SavedPages {
		saved[key] = true
	}
	for page := uint64(0); page <= *run.SmartHubLastPage; page++ {
		if !saved[simCardPageKey(domain.SimCardRunPage{Platform: domain.SimPlatformSmartHub, Page: page})] {
			return false
		}
	}
	for page := uint64(1); page <= *run.AcceleronixLastPage; page++ {
		if !saved[simCardPageKey(domain.SimCardRunPage{Platform: domain.SimPlatformAcceleronix, Page: page})] {
			return false
		}
	}
	return true
}

// StreamSimCardDailyUsage returns one snapshot per SIM for the UTC date.
// Missing previous-day snapshots are represented by nil and excluded from increments.
func StreamSimCardDailyUsage(date time.Time, consume func(total float64, previous *float64) error) error {
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
	defer cancel()
	month := date.Format("2006-01")
	day := date.Day()
	currentPath := fmt.Sprintf("$dailyUsage.%d.dataUsage", day)
	match := bson.D{{Key: "$match", Value: bson.M{
		"month":                           bson.M{"$in": []string{month, date.Format("200601")}},
		fmt.Sprintf("dailyUsage.%d", day): bson.M{"$exists": true},
	}}}
	pipeline := mongo.Pipeline{
		match,
		{{Key: "$sort", Value: bson.D{{Key: "updateTime", Value: -1}}}},
		{{Key: "$group", Value: bson.M{"_id": "$simId", "total": bson.M{"$first": currentPath}, "dailyUsage": bson.M{"$first": "$dailyUsage"}}}},
	}
	previousExpression := any(fmt.Sprintf("$dailyUsage.%d.dataUsage", day-1))
	if day == 1 {
		prev := time.Date(date.Year(), date.Month()-1, 1, 0, 0, 0, 0, time.UTC)
		prevDay := time.Date(date.Year(), date.Month(), 0, 0, 0, 0, 0, time.UTC).Day()
		pipeline = append(pipeline, bson.D{{Key: "$lookup", Value: bson.M{
			"from": CollectionName_SimCardMonthlyData,
			"let":  bson.M{"id": "$_id"},
			"pipeline": mongo.Pipeline{
				{{Key: "$match", Value: bson.M{"month": bson.M{"$in": []string{prev.Format("2006-01"), prev.Format("200601")}}, "$expr": bson.M{"$eq": bson.A{"$simId", "$$id"}}}}},
				{{Key: "$limit", Value: 1}},
			},
			"as": "previousMonth",
		}}})
		previousExpression = bson.M{"$arrayElemAt": bson.A{fmt.Sprintf("$previousMonth.dailyUsage.%d.dataUsage", prevDay), 0}}
	}
	pipeline = append(pipeline, bson.D{{Key: "$project", Value: bson.M{"total": 1, "previous": previousExpression}}})
	cursor, err := database.GetCollection(CollectionName_SimCardMonthlyData).Aggregate(ctx, pipeline, options.Aggregate().SetAllowDiskUse(true))
	if err != nil {
		return err
	}
	defer cursor.Close(ctx)
	for cursor.Next(ctx) {
		var row struct {
			Total    *float64 `bson:"total"`
			Previous *float64 `bson:"previous"`
		}
		if err := cursor.Decode(&row); err != nil {
			return err
		}
		if row.Total != nil {
			if err := consume(*row.Total, row.Previous); err != nil {
				return err
			}
		}
	}
	return cursor.Err()
}

func SaveSimCardDailyStatistics(stats domain.SimCardDailyStatistics) error {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	_, err := database.GetCollection(collectionSimCardStatistics).ReplaceOne(ctx, bson.M{"_id": stats.Date}, bson.M{"_id": stats.Date, "date": stats.Date, "cardCount": stats.CardCount, "totalOver200MB": stats.TotalOver200MB, "totalOver1GB": stats.TotalOver1GB, "totalOver2GB": stats.TotalOver2GB, "maxTotalKB": stats.MaxTotalKB, "incrementCardCount": stats.IncrementCardCount, "incrementOver20MB": stats.IncrementOver20MB, "incrementOver50MB": stats.IncrementOver50MB, "incrementOver200MB": stats.IncrementOver200MB, "maxIncrementKB": stats.MaxIncrementKB}, options.Replace().SetUpsert(true))
	return err
}

func MarkSimCardReportSent(date string) error {
	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
	defer cancel()
	_, err := database.GetCollection(collectionSimCardRun).UpdateOne(ctx, bson.M{"_id": date}, bson.M{"$set": bson.M{"sent": true}})
	return err
}