// This is Free Software under GNU Affero General Public License v >= 3.0
// without warranty, see README.md and license for details.
//
// SPDX-License-Identifier: AGPL-3.0-or-later
// License-Filename: LICENSES/AGPL-3.0.txt
//
// Copyright (C) 2018 by via donau
//   – Österreichische Wasserstraßen-Gesellschaft mbH
// Software engineering by Intevation GmbH
//
// Author(s):
//  * Raimund Renkert <raimund.renkert@intevation.de>

package imports

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"strings"
	"time"

	"gemma.intevation.de/gemma/pkg/common"
	"gemma.intevation.de/gemma/pkg/models"
	"gemma.intevation.de/gemma/pkg/soap/nts"
)

// GaugeMeasurement is an import job to import
// gauges measurement data from a NtS SOAP service.
type GaugeMeasurement struct {
	// URL is the URL of the SOAP service.
	URL string `json:"url"`
	// Insecure indicates if HTTPS traffic
	// should validate certificates or not.
	Insecure bool `json:"insecure"`
}

// GMJobKind is the import queue type identifier.
const GMJobKind JobKind = "gm"

const (
	listGaugesSQL = `
SELECT
  (location).country_code,
  (location).locode,
  (location).fairway_section,
  (location).orc,
  (location).hectometre
FROM waterway.gauges
WHERE (location).country_code = users.current_user_country()`

	insertGMSQL = `
INSERT INTO waterway.gauge_measurements (
  fk_gauge_id,
  measure_date,
  sender,
  language_code,
  country_code,
  date_issue,
  reference_code,
  water_level,
  predicted,
  is_waterlevel,
  value_min,
  value_max,
  date_info,
  source_organization,
  staging_done
) VALUES(
  ($1, $2, $3, $4, $5),
  $6,
  $7,
  $8,
  $9,
  $10,
  $11,
  $12,
  $13,
  $14,
  $15,
  $16,
  $17,
  $18,
  $19
)
RETURNING id`
)

type gmJobCreator struct{}

func init() {
	RegisterJobCreator(GMJobKind, gmJobCreator{})
}

func (gmJobCreator) Description() string {
	return "gauge measurements"
}

func (gmJobCreator) Create(_ JobKind, data string) (Job, error) {
	gm := new(GaugeMeasurement)
	if err := common.FromJSONString(data, gm); err != nil {
		return nil, err
	}
	return gm, nil
}

func (gmJobCreator) Depends() []string {
	return []string{
		"gauges",
		"gauge_measurements",
	}
}

func (gmJobCreator) AutoAccept() bool { return true }

// StageDone moves the imported gauge measurement out of the staging area.
// Currently doing nothing.
func (gmJobCreator) StageDone(context.Context, *sql.Tx, int64) error {
	return nil
}

// CleanUp of a gauge measurement import is a NOP.
func (*GaugeMeasurement) CleanUp() error { return nil }

// Do executes the actual bottleneck import.
func (gm *GaugeMeasurement) Do(
	ctx context.Context,
	importID int64,
	conn *sql.Conn,
	feedback Feedback,
) (interface{}, error) {

	// Get available gauges from database for use as filter in SOAP request
	var rows *sql.Rows

	rows, err := conn.QueryContext(ctx, listGaugesSQL)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	gauges := []models.GaugeMeasurement{}

	for rows.Next() {
		var g models.GaugeMeasurement
		if err = rows.Scan(
			&g.Gauge.CountryCode,
			&g.Gauge.LoCode,
			&g.Gauge.FairwaySection,
			&g.Gauge.Orc,
			&g.Gauge.Hectometre,
		); err != nil {
			return nil, err
		}
		gauges = append(gauges, g)
	}

	if err = rows.Err(); err != nil {
		return nil, err
	}

	// TODO get date_issue for selected gauges
	gids, err := gm.doForGM(ctx, gauges, conn, feedback)
	if err != nil {
		feedback.Error("Error processing %d gauges: %v", len(gauges), err)
		return nil, err
	}
	if len(gids) == 0 {
		feedback.Info("No new gauge measurements found")
		return nil, nil
	}
	// TODO: needs to be filled more useful.
	summary := struct {
		GaugeMeasuremets []string `json:"gaugeMeasurements"`
	}{
		GaugeMeasuremets: gids,
	}
	return &summary, err
}

// rescale returns a scaling function to bring the unit all to cm.
func rescale(unit string) (func(float32) float32, error) {

	var scale float32

	switch strings.ToLower(unit) {
	case "mm":
		scale = 0.1
	case "cm":
		scale = 1.0
	case "dm":
		scale = 10.0
	case "m":
		scale = 100.0
	case "hm":
		scale = 10000.0
	case "km":
		scale = 100000.0
	default:
		return nil, fmt.Errorf("unknown unit '%s'", unit)
	}

	fn := func(x float32) float32 { return scale * x }
	return fn, nil
}

func (gm *GaugeMeasurement) doForGM(
	ctx context.Context,
	gauges []models.GaugeMeasurement,
	conn *sql.Conn,
	feedback Feedback,
) ([]string, error) {
	start := time.Now()

	client := nts.NewINtSMessageService(gm.URL, gm.Insecure, nil)

	var idPairs []*nts.Id_pair
	for _, g := range gauges {
		isrs := g.Gauge.String()
		isrsID := nts.Isrs_code_type(isrs)
		idPairs = append(idPairs, &nts.Id_pair{
			Id: &isrsID,
		})
	}
	mt := nts.Message_type_typeWRM
	req := &nts.Get_messages_query{
		Message_type: &mt,
		Ids:          idPairs,
	}
	resp, err := client.Get_messages(req)
	if err != nil {
		feedback.Error("%v", err)
		return nil, err
	}

	if resp.Result_message == nil {
		err := errors.New("no gauge measurements found")
		for i, e := range resp.Result_error {
			feedback.Error("%d: %v", i, e)
		}
		return nil, err
	}

	result := resp.Result_message

	tx, err := conn.BeginTx(ctx, nil)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback()

	insertStmt, err := tx.PrepareContext(ctx, insertGMSQL)
	if err != nil {
		return nil, err
	}
	defer insertStmt.Close()

	var gid int64
	var gids []string
	for _, msg := range result {
		feedback.Info("Found %d gauges with measurements", len(msg.Wrm))
		for _, wrm := range msg.Wrm {
			currIsrs, err := models.IsrsFromString(string(*wrm.Geo_object.Id))
			if err != nil {
				feedback.Warn("Invalid ISRS code %v", err)
				continue
			}
			var referenceCode string
			if wrm.Reference_code == nil {
				feedback.Info("'Reference_code' not specified. Assuming 'ZPG'")
				referenceCode = "ZPG"
			} else {
				referenceCode = string(*wrm.Reference_code)
			}
			for _, measure := range wrm.Measure {
				var unit string
				if measure.Unit == nil {
					feedback.Info("'Unit' not specified. Assuming 'cm'")
					unit = "cm"
				} else {
					unit = string(*measure.Unit)
				}
				convert, err := rescale(unit)
				if err != nil {
					return nil, err
				}
				isWaterlevel := *measure.Measure_code == nts.Measure_code_enumWAL
				err = insertStmt.QueryRowContext(
					ctx,
					currIsrs.CountryCode,
					currIsrs.LoCode,
					currIsrs.FairwaySection,
					currIsrs.Orc,
					currIsrs.Hectometre,
					measure.Measuredate,
					msg.Identification.From,
					msg.Identification.Language_code,
					msg.Identification.Country_code,
					msg.Identification.Date_issue,
					referenceCode,
					convert(measure.Value),
					measure.Predicted,
					isWaterlevel,
					convert(measure.Value_min),
					convert(measure.Value_max),
					msg.Identification.Date_issue,
					msg.Identification.Originator,
					true, // staging_done
				).Scan(&gid)
				if err != nil {
					return nil, err
				}
			}
			feedback.Info("Inserted %d measurements for %s",
				len(wrm.Measure), currIsrs)
			gids = append(gids, currIsrs.String())
		}
	}
	feedback.Info("Storing gauge measurements took %s", time.Since(start))
	if err = tx.Commit(); err == nil {
		feedback.Info("Import of gauge measurements was successful")
	}

	return gids, nil
}