package cif

import (
	"time"

	"git.fjla.uk/owlboard/timetable-mgr/dbAccess"
	"git.fjla.uk/owlboard/timetable-mgr/helpers"
	"git.fjla.uk/owlboard/timetable-mgr/log"
	"git.fjla.uk/owlboard/timetable-mgr/nrod"
	"go.uber.org/zap"
)

// Replaces all existing CIF Data with a new download
func runCifFullDownload(cfg *helpers.Configuration) error {
	log.Msg.Info("Downloading all CIF Data")

	// Download CIF Data file
	url, err := getUpdateUrl("full")
	if err != nil {
		log.Msg.Error("Error getting download URL", zap.Error(err))
	}
	data, err := nrod.NrodDownload(url, cfg)
	if err != nil {
		log.Msg.Error("Error downloading CIF data", zap.Error(err))
	}

	// Parse CIF file
	parsed, err := parseCifData(data)
	if err != nil {
		log.Msg.Error("Error parsing CIF data", zap.Error(err))
		return err
	}

	// Drop timetable collection
	dbAccess.DropCollection(dbAccess.TimetableCollection)

	// Process CIF file
	err = processParsedCif(parsed)
	if err != nil {
		log.Msg.Error("Error processing CIF data", zap.Error(err))
	}

	// Generate & Write metadata

	return nil
}

// Runs a CIF Update for up to five days
func runCifUpdateDownload(cfg *helpers.Configuration, metadata *dbAccess.CifMetadata, days []time.Time) error {
	log.Msg.Info("Downloading CIF Updates")

	// Loop over dates
	for _, time := range days {
		log.Msg.Info("Downloading CIF File", zap.Time("CIF Data from", time))

		// Download CIF data file
		data, err := fetchUpdate(time, cfg)
		if err != nil {
			log.Msg.Error("Error fetching CIF update", zap.Error(err))
			return err
		}
		// Parse CIF file
		parsed, err := parseCifData(data)
		if err != nil {
			log.Msg.Error("Error parsing CIF data", zap.Error(err))
			return err
		}

		// Check metadata sequence - Handle a metadata sequence error. Probably by deleting metadata so next update triggers full download
		//// I need to check what the sequence looks like in a full download first.
		//// Regarding metadata, I will need to replace 'metadata *dbAccess.CifMetadata' with the new metadata to ensure it is checked correctly in each iteration.
		// Process CIF file

		metadata = generateMetadata(&parsed.header)
	}

	// Write metadata

	return nil
}

// Wraps nrod.NrodDownload() into a function which can handle downloading data for a given day
func fetchUpdate(t time.Time, cfg *helpers.Configuration) ([]byte, error) {
	url, err := getUpdateUrl("daily")
	if err != nil {
		return nil, err
	}

	// Append day string to URL
	url = url + getDayString(t)

	downloadedData, err := nrod.NrodDownload(url, cfg)
	if err != nil {
		return nil, err
	}
	return downloadedData, nil
}