// 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):
//  * Sascha L. Teichmann <sascha.teichmann@intevation.de>

package controllers

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"net/http"
	"sort"
	"strconv"

	"github.com/gorilla/mux"

	"gemma.intevation.de/gemma/pkg/auth"
	"gemma.intevation.de/gemma/pkg/imports"
	"gemma.intevation.de/gemma/pkg/scheduler"
)

const (
	selectImportConfigurationPrefix = `
SELECT
  id,
  username,
  kind,
  send_email,
  auto_accept,
  cron,
  url
FROM waterway.import_configuration`

	selectImportConfigurationSQL = selectImportConfigurationPrefix + `
ORDER by id`

	selectImportConfigurationIDSQL = selectImportConfigurationPrefix + `
WHERE id = $1`

	insertImportConfigurationSQL = `
INSERT INTO waterway.import_configuration
(username, kind, cron, send_email, auto_accept, url)
VALUES ($1, $2, $3, $4, $5, $6)
RETURNING id`

	insertImportConfigurationAttributeSQL = `
INSERT INTO waterway.import_configuration_attributes
(import_configuration_id, k, v)
VALUES ($1, $2, $3)`

	hasImportConfigurationSQL = `
SELECT true FROM waterway.import_configuration
WHERE id = $1`

	deleteImportConfiguationAttributesSQL = `
DELETE FROM waterway.import_configuration_attributes
WHERE id = $1`

	deleteImportConfiguationSQL = `
DELETE FROM waterway.import_configuration
WHERE id = $1`

	updateImportConfigurationSQL = `
UPDATE waterway.import_configuration SET
  username = $2
  kind = $3,
  cron = $4,
  url = $5,
  send_email = $6,
  auto_accept = $7
WHERE id = $1
`
)

func modifyImportConfig(
	input interface{},
	req *http.Request,
	conn *sql.Conn,
) (jr JSONResult, err error) {

	ctx := req.Context()

	importConfig := input.(*imports.Config)

	id, _ := strconv.ParseInt(mux.Vars(req)["id"], 10, 64)

	var tx *sql.Tx

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

	var (
		entry imports.IDConfig
		kind  string
		cron  sql.NullString
		url   sql.NullString
	)

	err = conn.QueryRowContext(ctx, selectImportConfigurationIDSQL, id).Scan(
		&entry.ID,
		&entry.User,
		&kind,
		&entry.SendEMail,
		&entry.AutoAccept,
		&cron,
		&url,
	)

	switch {
	case err == sql.ErrNoRows:
		err = JSONError{
			Code:    http.StatusNotFound,
			Message: fmt.Sprintf("No schedule %d found", id),
		}
		return
	case err != nil:
		return
	}

	session, _ := auth.GetSession(req)

	entry.SendEMail = importConfig.SendEMail
	entry.AutoAccept = importConfig.AutoAccept

	if importConfig.Cron != nil {
		cron = sql.NullString{String: string(*importConfig.Cron), Valid: true}
	}

	if importConfig.URL != nil {
		url = sql.NullString{String: *importConfig.URL, Valid: true}
	}

	if _, err = tx.ExecContext(ctx, updateImportConfigurationSQL,
		id,
		session.User,
		string(importConfig.Kind),
		cron,
		url,
		importConfig.SendEMail,
		importConfig.AutoAccept,
	); err != nil {
		return
	}

	if importConfig.Attributes != nil {
		if _, err = tx.ExecContext(ctx, deleteImportConfiguationAttributesSQL, id); err != nil {
			return
		}
		if err = storeConfigAttributes(ctx, tx, id, importConfig.Attributes); err != nil {
			return
		}
	}

	scheduler.UnbindByID(id)

	if cron.Valid {
		if err = scheduler.BindAction(
			string(importConfig.Kind),
			cron.String,
			id,
		); err != nil {
			return
		}
	}

	if err = tx.Commit(); err != nil {
		return
	}

	var result = struct {
		ID int64 `json:"id"`
	}{
		ID: id,
	}

	jr = JSONResult{Result: &result}
	return
}

func infoImportConfig(
	_ interface{},
	req *http.Request,
	conn *sql.Conn,
) (jr JSONResult, err error) {

	ctx := req.Context()

	id, _ := strconv.ParseInt(mux.Vars(req)["id"], 10, 64)

	var (
		entry imports.IDConfig
		kind  string
		cron  sql.NullString
		url   sql.NullString
	)

	err = conn.QueryRowContext(ctx, selectImportConfigurationIDSQL, id).Scan(
		&entry.ID,
		&entry.User,
		&kind,
		&entry.SendEMail,
		&entry.AutoAccept,
		&cron,
		&url,
	)

	switch {
	case err == sql.ErrNoRows:
		err = JSONError{
			Code:    http.StatusNotFound,
			Message: fmt.Sprintf("No schedule %d found", id),
		}
		return
	case err != nil:
		return
	}

	entry.Kind = imports.ImportKind(kind)
	if cron.Valid {
		cs := imports.CronSpec(cron.String)
		entry.Cron = &cs
	}
	if url.Valid {
		entry.URL = &url.String
	}

	jr = JSONResult{Result: &entry}
	return
}

func deleteImportConfig(
	_ interface{},
	req *http.Request,
	conn *sql.Conn,
) (jr JSONResult, err error) {

	ctx := req.Context()

	id, _ := strconv.ParseInt(mux.Vars(req)["id"], 10, 64)

	var tx *sql.Tx
	if tx, err = conn.BeginTx(ctx, nil); err != nil {
		return
	}
	defer tx.Rollback()

	var found bool
	err = tx.QueryRowContext(ctx, hasImportConfigurationSQL, id).Scan(&found)
	switch {
	case err == sql.ErrNoRows:
		err = JSONError{
			Code:    http.StatusNotFound,
			Message: fmt.Sprintf("No schedule %d found", id),
		}
		return
	case err != nil:
		return
	case !found:
		err = errors.New("Unexpected result")
		return
	}

	if _, err = tx.ExecContext(ctx, deleteImportConfiguationAttributesSQL, id); err != nil {
		return
	}

	if _, err = tx.ExecContext(ctx, deleteImportConfiguationSQL, id); err != nil {
		return
	}

	// Remove from running scheduler.
	scheduler.UnbindByID(id)

	if err = tx.Commit(); err != nil {
		return
	}

	var result = struct {
		ID int64 `json:"id"`
	}{
		ID: id,
	}

	jr = JSONResult{Result: &result}
	return
}

func storeConfigAttributes(
	ctx context.Context,
	tx *sql.Tx,
	id int64,
	attrs imports.ConfigAttributes,
) error {
	if len(attrs) == 0 {
		return nil
	}
	attrStmt, err := tx.PrepareContext(ctx, insertImportConfigurationAttributeSQL)
	if err != nil {
		return err
	}
	defer attrStmt.Close()
	// Sort to make it deterministic
	keys := make([]string, len(attrs))
	i := 0
	for key := range attrs {
		keys[i] = key
		i++
	}
	sort.Strings(keys)
	for _, key := range keys {
		if _, err := attrStmt.ExecContext(ctx, id, key, attrs[key]); err != nil {
			return err
		}
	}
	return nil
}

func addImportConfig(
	input interface{},
	req *http.Request,
	conn *sql.Conn,
) (jr JSONResult, err error) {

	importConfig := input.(*imports.Config)

	session, _ := auth.GetSession(req)

	var cron, url sql.NullString

	if importConfig.Cron != nil {
		cron = sql.NullString{String: string(*importConfig.Cron), Valid: true}
	}
	if importConfig.URL != nil {
		url = sql.NullString{String: *importConfig.URL, Valid: true}
	}

	ctx := req.Context()

	var tx *sql.Tx

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

	var id int64
	if err = tx.QueryRowContext(
		ctx,
		insertImportConfigurationSQL,
		session.User,
		string(importConfig.Kind),
		cron,
		importConfig.SendEMail,
		importConfig.AutoAccept,
		url,
	).Scan(&id); err != nil {
		return
	}

	// Store extra attributes
	if err = storeConfigAttributes(ctx, tx, id, importConfig.Attributes); err != nil {
		return
	}

	// Need to start a scheduler job right away?
	if importConfig.Cron != nil {
		if err = scheduler.BindAction(
			string(importConfig.Kind),
			string(*importConfig.Cron),
			id,
		); err != nil {
			return
		}
	}

	if err = tx.Commit(); err != nil {
		scheduler.UnbindByID(id)
	}

	var result = struct {
		ID int64 `json:"id"`
	}{
		ID: id,
	}

	jr = JSONResult{
		Code:   http.StatusCreated,
		Result: &result,
	}
	return
}

func listImportConfigs(
	_ interface{},
	req *http.Request,
	conn *sql.Conn,
) (jr JSONResult, err error) {

	ctx := req.Context()
	var rows *sql.Rows

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

	list := []*imports.IDConfig{}

	for rows.Next() {
		var (
			entry imports.IDConfig
			kind  string
			cron  sql.NullString
			url   sql.NullString
		)
		if err = rows.Scan(
			&entry.ID,
			&entry.User,
			&kind,
			&entry.SendEMail,
			&entry.AutoAccept,
			&cron,
			&url,
		); err != nil {
			return
		}
		entry.Kind = imports.ImportKind(kind)
		if cron.Valid {
			cs := imports.CronSpec(cron.String)
			entry.Cron = &cs
		}
		if url.Valid {
			entry.URL = &url.String
		}
		list = append(list, &entry)
	}

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

	jr = JSONResult{Result: list}
	return
}