// 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) 2019 by via donau
//   – Österreichische Wasserstraßen-Gesellschaft mbH
// Software engineering by Intevation GmbH
//
// Author(s):
//  * Sascha L. Teichmann <sascha.teichmann@intevation.de>
//  * Markus Kottländer <markus.kottlaender@intevation.de>

package geoserver

import (
	"context"
	"database/sql"
	"strings"
	"text/template"

	"gemma.intevation.de/gemma/pkg/auth"
	"gemma.intevation.de/gemma/pkg/models"
)

const (
	selectClassBreaksSQL = `
SELECT config_val FROM sys_admin.system_config
WHERE config_key = $1`
)

func init() {
	RegisterStylePreprocessor(
		"sounding_results_contour_lines_geoserver",
		templateContourLinesFunc("morphology_classbreaks"))
	RegisterStylePreprocessor(
		"sounding_differences",
		templateContourLinesFunc("morphology_classbreaks_compare"))
}

func templateContourLinesFunc(configKey string) func(string) (string, error) {
	return func(data string) (string, error) {
		return templateContourLines(data, configKey)
	}
}

func templateContourLines(data, configKey string) (string, error) {
	tmpl, err := template.New("template").Parse(data)
	if err != nil {
		return "", err
	}

	var cb []models.ClassBreak

	if cb, err = countourLinesClassBreaks(configKey); err != nil {
		return "", err
	}

	var buf strings.Builder
	if err = tmpl.Execute(&buf, cb); err != nil {
		return "", err
	}
	return buf.String(), nil
}

func countourLinesClassBreaks(configKey string) ([]models.ClassBreak, error) {

	var config string
	ctx := context.Background()
	if err := auth.RunAs(
		ctx,
		"sys_admin",
		func(conn *sql.Conn) error {
			return conn.QueryRowContext(
				ctx,
				selectClassBreaksSQL,
				configKey,
			).Scan(&config)
		},
	); err != nil {
		return nil, err
	}

	cc, err := models.ParseColorValues(config)
	if err != nil {
		return nil, err
	}

	return cc.ClassBreaks(), nil
}