package cif

import (
	"time"

	"git.fjla.uk/owlboard/go-types/pkg/database"
	"git.fjla.uk/owlboard/go-types/pkg/upstreamApi"
	"git.fjla.uk/owlboard/timetable-mgr/dbAccess"
	"git.fjla.uk/owlboard/timetable-mgr/log"
	"go.uber.org/zap"
)

// Processes parsed CIF data and applies the data to the database
func processParsedCif(data *parsedData) error {
	log.Msg.Debug("Starting CIF Processing")

	// Batch size for processing
	batchSize := 250 // Needs optimising for better RAM use.  1000 ~ 5.7GB, 500 ~ 5.5GB, 750 ~ 5.2GB

	// Process deletions in batches
	for i := 0; i < len(data.sched); i += batchSize {
		end := i + batchSize
		if end > len(data.sched) {
			end = len(data.sched)
		}
		deleteBatch := make([]*upstreamApi.JsonScheduleV1, 0)
		for _, item := range data.sched[i:end] {
			if item.TransactionType == "Delete" {
				deleteItem := item
				deleteBatch = append(deleteBatch, &deleteItem)
			}
		}
		if len(deleteBatch) > 0 {
			err := doDeletions(deleteBatch)
			if err != nil {
				log.Msg.Error("Error deleting CIF Entries", zap.Error(err))
				return err
			}
		}
	}

	// Process creations in batches
	for i := 0; i < len(data.sched); i += batchSize {
		end := i + batchSize
		if end > len(data.sched) {
			end = len(data.sched)
		}
		createBatch := make([]*upstreamApi.JsonScheduleV1, 0)
		for _, item := range data.sched[i:end] {
			if item.TransactionType == "Create" {
				createItem := item
				createBatch = append(createBatch, &createItem)
			}
		}
		if len(createBatch) > 0 {
			err := doCreations(createBatch)
			if err != nil {
				log.Msg.Error("Error creating CIF Entries", zap.Error(err))
				return err
			}
		}
	}

	log.Msg.Debug("CIF Processing complete")
	return nil
}

// Create delete query types and pass to the function which batches the deletions
func doDeletions(deletions []*upstreamApi.JsonScheduleV1) error {
	deleteQueries := make([]database.DeleteQuery, 0)
	for _, item := range deletions {
		query := database.DeleteQuery{
			ScheduleStartDate: ParseCifDate(&item.ScheduleStartDate, "start"),
			StpIndicator:      item.CifStpIndicator,
			TrainUid:          item.CifTrainUid,
		}

		deleteQueries = append(deleteQueries, query)
	}

	err := dbAccess.DeleteCifEntries(deleteQueries)
	if err != nil {
		log.Msg.Error("Error deleting documents", zap.Error(err))
		return err
	}

	return nil
}

// Convert to the correct struct for the database and pass to the function which batches insertions
func doCreations(creations []*upstreamApi.JsonScheduleV1) error {
	createDocuments := make([]database.Service, 0)
	for _, item := range creations {
		document, err := ConvertServiceType(item, false)
		if err != nil {
			log.Msg.Error("Error converting JsonSchedule to Service type", zap.Error(err))
		}

		createDocuments = append(createDocuments, *document)
	}

	err := dbAccess.CreateCifEntries(createDocuments)
	if err != nil {
		log.Msg.Error("Error creating documents", zap.Error(err))
		return err
	}

	return nil
}

// Accepts the JsonTimetableV1 struct which contains CIF File metadata and produces a DB Ready struct.
func generateMetadata(header *upstreamApi.JsonTimetableV1) *dbAccess.CifMetadata {
	newMetadata := dbAccess.CifMetadata{
		Doctype:       dbAccess.Doctype,
		LastTimestamp: header.Timestamp,
		LastUpdate:    time.Now().In(londonTimezone),
		LastSequence:  header.Metadata.Sequence,
	}

	return &newMetadata
}