// 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, 2019 by via donau
//   – Österreichische Wasserstraßen-Gesellschaft mbH
// Software engineering by Intevation GmbH
//
// Author(s):
//  * Sascha L. Teichmann <sascha.teichmann@intevation.de>
//  * Tom Gottfried <tom.gottfried@intevation.de>

package imports

import (
	"context"
	"database/sql"
	"errors"
	"regexp"
	"strconv"
	"time"

	"gemma.intevation.de/gemma/pkg/soap/ifbn"
)

// Bottleneck is an import job to import
// bottlenecks from an IFBN SOAP service.
type Bottleneck struct {
	// URL is the URL of the SOAP service.
	URL string `json:"url"`
	// Tolerance used for axis snapping
	Tolerance float64 `json:"tolerance"`
	// Insecure indicates if HTTPS traffic
	// should validate certificates or not.
	Insecure bool `json:"insecure"`
}

// BNJobKind is the import queue type identifier.
const BNJobKind JobKind = "bn"

const (
	hasBottleneckSQL = `
SELECT true FROM waterway.bottlenecks WHERE bottleneck_id = $1`

	insertBottleneckSQL = `
INSERT INTO waterway.bottlenecks (
  bottleneck_id,
  fk_g_fid,
  objnam,
  nobjnm,
  stretch,
  area,
  rb,
  lb,
  responsible_country,
  revisiting_time,
  limiting,
  date_info,
  source_organization
) VALUES(
  $1,
  isrs_fromText($2),
  $3,
  $4,
  isrsrange(least(isrs_fromText($5), isrs_fromText($6)),
            greatest(isrs_fromText($5), isrs_fromText($6))),
  ISRSrange_area(
    ISRSrange_axis(isrsrange(least(isrs_fromText($5), isrs_fromText($6)),
                             greatest(isrs_fromText($5), isrs_fromText($6))),
                   $14),
    (SELECT ST_Collect(CAST(area AS geometry))
        FROM waterway.waterway_area)),
  $7,
  $8,
  $9,
  $10,
  $11,
  $12,
  $13
)
RETURNING id`
)

type bnJobCreator struct{}

func init() {
	RegisterJobCreator(BNJobKind, bnJobCreator{})
}

func (bnJobCreator) Description() string { return "bottlenecks" }

func (bnJobCreator) AutoAccept() bool { return false }

func (bnJobCreator) Create() Job { return new(Bottleneck) }

func (bnJobCreator) Depends() []string {
	return []string{
		"gauges",
		"bottlenecks",
	}
}

const (
	bnStageDoneSQL = `
UPDATE waterway.bottlenecks SET staging_done = true
WHERE id IN (
  SELECT key from import.track_imports
  WHERE import_id = $1 AND
        relation = 'waterway.bottlenecks'::regclass)`
)

// StageDone moves the imported bottleneck out of the staging area.
func (bnJobCreator) StageDone(
	ctx context.Context,
	tx *sql.Tx,
	id int64,
) error {
	_, err := tx.ExecContext(ctx, bnStageDoneSQL, id)
	return err
}

// CleanUp of a bottleneck import is a NOP.
func (*Bottleneck) CleanUp() error { return nil }

var rblbRe = regexp.MustCompile(`(..)_(..)`)

func splitRBLB(s string) (*string, *string) {
	m := rblbRe.FindStringSubmatch(s)
	if len(m) == 0 {
		return nil, nil
	}
	return &m[1], &m[2]
}

func revisitingTime(s string) int {
	v, err := strconv.Atoi(s)
	if err != nil {
		v = 0
	}
	return v
}

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

	fetch := func() ([]*ifbn.BottleNeckType, error) {
		client := ifbn.NewIBottleneckService(bn.URL, bn.Insecure, nil)

		req := &ifbn.Export_bn_by_isrs{}

		resp, err := client.Export_bn_by_isrs(req)
		if err != nil {
			return nil, err
		}

		if resp.Export_bn_by_isrsResult == nil {
			return nil, errors.New("no Bottlenecks found")
		}

		return resp.Export_bn_by_isrsResult.BottleNeckType, nil
	}

	return storeBottlenecks(ctx, fetch, importID, conn, feedback, bn.Tolerance)
}

func storeBottlenecks(
	ctx context.Context,
	fetch func() ([]*ifbn.BottleNeckType, error),
	importID int64,
	conn *sql.Conn,
	feedback Feedback,
	tolerance float64,
) (interface{}, error) {
	start := time.Now()

	bns, err := fetch()
	if err != nil {
		return nil, err
	}

	feedback.Info("Found %d bottlenecks for import", len(bns))

	var hasStmt, insertStmt, trackStmt *sql.Stmt

	for _, x := range []struct {
		sql  string
		stmt **sql.Stmt
	}{
		{hasBottleneckSQL, &hasStmt},
		{insertBottleneckSQL, &insertStmt},
		{trackImportSQL, &trackStmt},
	} {
		var err error
		if *x.stmt, err = conn.PrepareContext(ctx, x.sql); err != nil {
			return nil, err
		}
		defer (*x.stmt).Close()
	}

	var nids []string

	feedback.Info("Tolerance used to snap waterway axis: %g", tolerance)

	for _, bn := range bns {
		if err := storeBottleneck(
			ctx, importID, conn, feedback, bn, &nids, tolerance,
			hasStmt, insertStmt, trackStmt); err != nil {
			return nil, err
		}
	}
	if len(nids) == 0 {
		return nil, UnchangedError("No new bottlenecks inserted")
	}

	feedback.Info("Storing %d bottlenecks took %s", len(nids), time.Since(start))
	feedback.Info("Import of bottlenecks was successful")
	summary := struct {
		Bottlenecks []string `json:"bottlenecks"`
	}{
		Bottlenecks: nids,
	}
	return &summary, nil
}

func storeBottleneck(
	ctx context.Context,
	importID int64,
	conn *sql.Conn,
	feedback Feedback,
	bn *ifbn.BottleNeckType,
	nids *[]string,
	tolerance float64,
	hasStmt, insertStmt, trackStmt *sql.Stmt,
) error {

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

	var found bool
	err = tx.Stmt(hasStmt).QueryRowContext(ctx, bn.Bottleneck_id).Scan(&found)
	switch {
	case err == sql.ErrNoRows:
		// This is good.
	case err != nil:
		return err
	case found:
		feedback.Info("'%s' already in database. Skip", bn.OBJNAM)
		// TODO: Deep comparison database vs. SOAP.
		return nil
	}

	rb, lb := splitRBLB(bn.Rb_lb)

	var limiting, country string

	if bn.Limiting_factor != nil {
		limiting = string(*bn.Limiting_factor)
	}

	if bn.Responsible_country != nil {
		country = string(*bn.Responsible_country)
	}

	var nid int64

	err = tx.Stmt(insertStmt).QueryRowContext(
		ctx,
		bn.Bottleneck_id,
		bn.Fk_g_fid,
		bn.OBJNAM,
		bn.NOBJNM,
		bn.From_ISRS, bn.To_ISRS,
		rb,
		lb,
		country,
		revisitingTime(bn.Revisiting_time),
		limiting,
		bn.Date_Info,
		bn.Source,
		tolerance,
	).Scan(&nid)
	if err != nil {
		feedback.Warn("Failed to insert '%s' into database", bn.OBJNAM)
		feedback.Warn(handleError(err).Error())
		return nil
	}

	if _, err := tx.Stmt(trackStmt).ExecContext(
		ctx, importID, "waterway.bottlenecks", nid,
	); err != nil {
		return err
	}
	if err = tx.Commit(); err != nil {
		return err
	}
	feedback.Info("Inserted '%s' into database", bn.OBJNAM)
	*nids = append(*nids, bn.Bottleneck_id)
	return nil
}