package cif

import (
	"encoding/json"
	"errors"
	"io"

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

// Accepts the CIF data as a stream and outputs parsed data
func parseCifDataStream(dataStream io.ReadCloser) (*ParsedData, error) {
	defer dataStream.Close()
	log.Debug("Starting CIF Datastream parsing")
	if dataStream == nil {
		return nil, errors.New("unable to parse nil pointer")
	}

	var parsed ParsedData
	parsed.Assoc = make([]upstreamApi.JsonAssociationV1, 0)
	parsed.Sched = make([]upstreamApi.JsonScheduleV1, 0)

	// Create JSON Decoder
	decoder := json.NewDecoder(dataStream)

	// Iterate over JSON Objects using stream decoder
	for decoder.More() {
		var obj map[string]json.RawMessage
		if err := decoder.Decode(&obj); err != nil {
			log.Error("Error decoding JSON String")
			return nil, err
		}

		// Handle parsed data
		for key, value := range obj {
			switch key {
			case "JsonTimetableV1":
				var timetable upstreamApi.JsonTimetableV1
				if err := json.Unmarshal(value, &timetable); err != nil {
					log.Error("Error decoding JSONTimetableV1 object", zap.Error(err))
					continue
				}
				parsed.Header = timetable
			case "TiplocV1":
				// This data is not used and is sourced from CORPUS
				continue
			case "JsonAssociationV1":
				// Association data is not currently used
				// but may be used in the future
				continue
			case "JsonScheduleV1":
				var schedule upstreamApi.JsonScheduleV1
				if err := json.Unmarshal(value, &schedule); err != nil {
					log.Error("Error decoding JSONScheduleV1 object", zap.Error(err))
					continue
				}
				parsed.Sched = append(parsed.Sched, schedule)
			case "EOF":
				log.Debug("Reached EOF")
			default:
				log.Warn("Unknown CIF Data type", zap.String("key", key))
			}
		}
	}
	log.Debug("CIF Parsing completed")
	return &parsed, nil
}