// 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"
	"strings"
	"time"

	"gemma.intevation.de/gemma/pkg/soap/ifbn"
	"github.com/jackc/pgx/pgtype"
)

// 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 (
	insertBottleneckSQL = `
WITH
bounds (b) AS (VALUES (isrs_fromText($6)), (isrs_fromText($7))),
r AS (SELECT isrsrange(
    (SELECT b FROM bounds ORDER BY b USING <~ FETCH FIRST ROW ONLY),
    (SELECT b FROM bounds ORDER BY b USING >~ FETCH FIRST ROW ONLY)) AS r)
INSERT INTO waterway.bottlenecks (
  bottleneck_id,
  validity,
  gauge_location,
  gauge_validity,
  objnam,
  nobjnm,
  stretch,
  area,
  rb,
  lb,
  responsible_country,
  revisiting_time,
  limiting,
  date_info,
  source_organization
) SELECT
  $1,
  validity * $2, -- intersections with gauge validity ranges
  location,
  validity,
  $4,
  $5,
  (SELECT r FROM r),
  ISRSrange_area(
    ISRSrange_axis((SELECT r FROM r),
                   $15),
    (SELECT ST_Collect(CAST(area AS geometry))
        FROM waterway.waterway_area)),
  $8,
  $9,
  $10,
  $11,
  $12,
  $13,
  $14
  FROM waterway.gauges
  WHERE location = isrs_fromText($3) AND validity && $2
ON CONFLICT (bottleneck_id, validity) DO UPDATE SET
    gauge_location = EXCLUDED.gauge_location,
    gauge_validity = EXCLUDED.gauge_validity,
    objnam = EXCLUDED.objnam,
    nobjnm = EXCLUDED.nobjnm,
    stretch = EXCLUDED.stretch,
    area = EXCLUDED.area,
    rb = EXCLUDED.rb,
    lb = EXCLUDED.lb,
    responsible_country = EXCLUDED.responsible_country,
    revisiting_time = EXCLUDED.revisiting_time,
    limiting = EXCLUDED.limiting,
    date_info = EXCLUDED.date_info,
    source_organization = EXCLUDED.source_organization
RETURNING id
`

	findExactMatchBottleneckSQL = `
WITH
bounds (b) AS (VALUES (isrs_fromText($6)), (isrs_fromText($7))),
r AS (SELECT isrsrange(
    (SELECT b FROM bounds ORDER BY b USING <~ FETCH FIRST ROW ONLY),
    (SELECT b FROM bounds ORDER BY b USING >~ FETCH FIRST ROW ONLY)) AS r)
SELECT id FROM waterway.bottlenecks
WHERE (
  bottleneck_id,
  validity,
  gauge_location,
  gauge_validity,
  objnam,
  nobjnm,
  stretch,
  rb,
  lb,
  responsible_country,
  revisiting_time,
  limiting,
  date_info,
  source_organization,
  staging_done
) = ( SELECT
  $1,
  validity * $2, -- intersections with gauge validity ranges
  location,
  validity,
  $4,
  $5,
  (SELECT r FROM r),
  $8,
  $9,
  $10,
  $11::smallint,
  $12,
  $13::timestamptz,
  $14,
  true
  FROM waterway.gauges
  WHERE location = isrs_fromText($3) AND validity && $2
)
`

	// Alignment with gauge validity might have generated new entries
	// for the same time range. Thus, remove the old ones
	deleteObsoleteBNSQL = `
DELETE FROM waterway.bottlenecks
WHERE bottleneck_id = $1 AND validity <@ $2 AND id <> ALL($3)
`

	fixBNValiditySQL = `
UPDATE waterway.bottlenecks SET
   -- Set enddate of old entry to new startdate in case of overlap:
  validity = validity - $2
WHERE bottleneck_id = $1
  AND validity && $2 AND NOT validity <@ $2
`

	deleteBottleneckMaterialSQL = `
WITH del AS (
  DELETE FROM waterway.bottlenecks_riverbed_materials
  WHERE bottleneck_id = ANY($1)
    AND riverbed <> ALL($2)
  RETURNING riverbed)
SELECT DISTINCT riverbed FROM del
`

	insertBottleneckMaterialSQL = `
INSERT INTO waterway.bottlenecks_riverbed_materials (
   bottleneck_id,
   riverbed
) SELECT *
FROM unnest(CAST($1 AS int[])) AS bns,
  unnest(CAST($2 AS varchar[])) AS materials
ON CONFLICT (bottleneck_id, riverbed) DO NOTHING
`
)

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() [2][]string {
	return [2][]string{
		{"bottlenecks", "bottlenecks_riverbed_materials"},
		{"gauges", "distance_marks_virtual", "waterway_axis", "waterway_area"},
	}
}

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]
}

// 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(
				"The requested service returned no bottlenecks")
		}

		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 insertStmt, findExactMatchingBNStmt, deleteObsoleteBNStmt,
		fixValidityStmt, deleteMaterialStmt, insertMaterialStmt,
		trackStmt *sql.Stmt

	for _, x := range []struct {
		sql  string
		stmt **sql.Stmt
	}{
		{insertBottleneckSQL, &insertStmt},
		{findExactMatchBottleneckSQL, &findExactMatchingBNStmt},
		{deleteObsoleteBNSQL, &deleteObsoleteBNStmt},
		{fixBNValiditySQL, &fixValidityStmt},
		{deleteBottleneckMaterialSQL, &deleteMaterialStmt},
		{insertBottleneckMaterialSQL, &insertMaterialStmt},
		{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,
			insertStmt, findExactMatchingBNStmt, deleteObsoleteBNStmt,
			fixValidityStmt, deleteMaterialStmt, insertMaterialStmt,
			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,
	insertStmt, findExactMatchingBNStmt, deleteObsoleteBNStmt,
	fixValidityStmt, deleteMaterialStmt, insertMaterialStmt,
	trackStmt *sql.Stmt,
) error {
	feedback.Info("Processing %s (%s)", bn.OBJNAM, bn.Bottleneck_id)

	var tfrom, tto pgtype.Timestamptz
	var uBound pgtype.BoundType

	if bn.AdditionalData == nil || bn.AdditionalData.KeyValuePair == nil {
		// This is a workaround for the fact that most BN data does not
		// contain the optional validity information.
		//
		// The current solution makes every change in the data an
		// update, which might be not the best solution.  Alternative
		// approaches could include usingthe Date Info of the data as
		// start date, and maybe even inspecting the details of changed
		// data for hints wether an update or historisation with a new
		// version is advisable.
		//
		// Never the less, the current solution "just works" for the
		// rtime being...  --  sw
		feedback.Warn("No validity information, assuming infinite validity.")
		tfrom.Set(time.Date(1970, time.January, 1, 0, 0, 0, 0, time.UTC))
		uBound = pgtype.Unbounded
	} else {
		const (
			fromKey = "Valid_from_date"
			toKey   = "Valid_to_date"
		)
		fromTo := make(map[string]time.Time)
		for _, kv := range bn.AdditionalData.KeyValuePair {
			k := string(kv.Key)
			if k == fromKey || k == toKey {
				if t, err := time.Parse(time.RFC3339, kv.Value); err != nil {
					return err
				} else {
					fromTo[k] = t
				}
			}
		}

		if t, ok := fromTo[fromKey]; ok {
			tfrom.Set(t)
		} else {
			feedback.Warn("Missing start date")
			return nil
		}

		if t, ok := fromTo[toKey]; ok {
			tto.Set(t)
			uBound = pgtype.Exclusive
		} else {
			uBound = pgtype.Unbounded
		}
	}

	validity := pgtype.Tstzrange{
		Lower:     tfrom,
		Upper:     tto,
		LowerType: pgtype.Inclusive,
		UpperType: uBound,
		Status:    pgtype.Present,
	}

	rb, lb := splitRBLB(bn.Rb_lb)

	var revisitingTime *int
	if bn.Revisiting_time != nil &&
		len(strings.TrimSpace(*bn.Revisiting_time)) > 0 {
		i, err := strconv.Atoi(*bn.Revisiting_time)
		if err != nil {
			feedback.Warn(
				"Cannot convert given revisiting time '%s' to number of months",
				*bn.Revisiting_time)
		} else {
			revisitingTime = &i
		}
	}

	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 materials []string
	if bn.Riverbed != nil {
		for _, material := range bn.Riverbed.Material {
			if material != nil {
				materials = append(materials, string(*material))
			}
		}
	}

	// Check if an bottleneck identical to the one we would insert already
	// exists:
	bns, err := findExactMatchingBNStmt.QueryContext(ctx,
		bn.Bottleneck_id,
		&validity,
		bn.Fk_g_fid,
		bn.OBJNAM,
		bn.NOBJNM,
		bn.From_ISRS, bn.To_ISRS,
		rb,
		lb,
		country,
		revisitingTime,
		limiting,
		bn.Date_Info,
		bn.Source,
	)

	if err != nil {
		return err
	}
	defer bns.Close()
	if bns.Next() {
		feedback.Info("unchanged")
		return nil
	}

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

	var bnIds []int64
	bns, err = tx.StmtContext(ctx, insertStmt).QueryContext(ctx,
		bn.Bottleneck_id,
		&validity,
		bn.Fk_g_fid,
		bn.OBJNAM,
		bn.NOBJNM,
		bn.From_ISRS, bn.To_ISRS,
		rb,
		lb,
		country,
		revisitingTime,
		limiting,
		bn.Date_Info,
		bn.Source,
		tolerance,
	)
	if err != nil {
		feedback.Warn(handleError(err).Error())
		return nil
	}
	defer bns.Close()
	for bns.Next() {
		var nid int64
		if err := bns.Scan(&nid); err != nil {
			return err
		}
		bnIds = append(bnIds, nid)
	}
	if err := bns.Err(); err != nil {
		feedback.Warn(handleError(err).Error())
		return nil
	}
	if len(bnIds) == 0 {
		feedback.Warn(
			"No gauge matching '%s' or given time available", bn.Fk_g_fid)
		return nil
	}

	// Remove obsolete bottleneck version entries
	var pgBnIds pgtype.Int8Array
	pgBnIds.Set(bnIds)
	if _, err = tx.StmtContext(ctx, deleteObsoleteBNStmt).ExecContext(ctx,
		bn.Bottleneck_id,
		&validity,
		&pgBnIds,
	); err != nil {
		feedback.Warn(handleError(err).Error())
		if err2 := tx.Rollback(); err2 != nil {
			return err2
		}
		return nil
	}

	// Set end of validity of old version to start of new version
	// in case of overlap
	if _, err = tx.StmtContext(ctx, fixValidityStmt).ExecContext(ctx,
		bn.Bottleneck_id,
		validity,
	); err != nil {
		feedback.Warn(handleError(err).Error())
		if err2 := tx.Rollback(); err2 != nil {
			return err2
		}
		return nil
	}

	if materials != nil {
		// Remove obsolete riverbed materials
		var pgMaterials pgtype.VarcharArray
		pgMaterials.Set(materials)
		mtls, err := tx.StmtContext(ctx,
			deleteMaterialStmt).QueryContext(ctx,
			&pgBnIds,
			&pgMaterials,
		)
		if err != nil {
			return err
		}
		defer mtls.Close()
		for mtls.Next() {
			var delMat string
			if err := mtls.Scan(&delMat); err != nil {
				return err
			}
			feedback.Warn("Removed riverbed material %s", delMat)
		}
		if err := mtls.Err(); err != nil {
			return err
		}

		// Insert riverbed materials
		if _, err := tx.StmtContext(ctx, insertMaterialStmt).ExecContext(ctx,
			&pgBnIds,
			&pgMaterials,
		); err != nil {
			feedback.Warn("Failed to insert riverbed materials")
			feedback.Warn(handleError(err).Error())
			return nil
		}
	}

	for _, nid := range bnIds {
		if _, err := tx.StmtContext(ctx, trackStmt).ExecContext(
			ctx, importID, "waterway.bottlenecks", nid,
		); err != nil {
			return err
		}
	}
	if err = tx.Commit(); err != nil {
		return err
	}
	*nids = append(*nids, bn.Bottleneck_id)
	return nil
}