// 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>

package main

import (
	"bufio"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"strconv"
	"strings"

	"gemma.intevation.de/gemma/pkg/octree"
)

func loadXYZ(r io.Reader) (octree.MultiPointZ, error) {

	scanner := bufio.NewScanner(r)

	points := make(octree.MultiPointZ, 0, 2000000)

	var x, y, z float64
	var err error

	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if len(line) == 0 || strings.HasPrefix(line, "#") {
			continue
		}
		parts := strings.SplitN(line, " ", 3)
		if len(parts) != 3 {
			continue
		}

		if x, err = strconv.ParseFloat(parts[0], 64); err != nil {
			return nil, err
		}
		if y, err = strconv.ParseFloat(parts[1], 64); err != nil {
			return nil, err
		}
		if z, err = strconv.ParseFloat(parts[2], 64); err != nil {
			return nil, err
		}
		points = append(points, octree.Vertex{X: x, Y: y, Z: z})
	}

	return points, nil
}

func storeXYZ(points octree.MultiPointZ, w io.Writer) error {
	out := bufio.NewWriter(w)
	for i := range points {
		fmt.Fprintf(out, "%.5f,%.5f,%.5f\n",
			points[i].X, points[i].Y, points[i].Z)
	}
	return out.Flush()
}

func main() {

	var tolerance float64

	flag.Float64Var(&tolerance, "t", 0.1, "accepted tolerance (shorthand)")
	flag.Float64Var(&tolerance, "tolerance", 0.1, "accepted tolerance")

	flag.Parse()

	points, err := loadXYZ(os.Stdin)
	if err != nil {
		log.Fatalf("err: %v\n", err)
	}

	points = points.Simplify(tolerance)

	if err := storeXYZ(points, os.Stdout); err != nil {
		log.Fatalf("err: %v\n", err)
	}
}