unit gpxunit;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, mystringlistunit;

type
  tTrkPt = record
    lat,lon,ele,time: string;
  end;
  tTrack = record
    name:   string;
    trkPts: array of tTrkPt;
  end;
  tGpxInhalt = record
    kopf: string;
    trks: array of tTrack;
  end;
  tGpxFile = class
    prefix: tMyStringList;
    gpx:    array of tGpxInhalt;
    constructor create;
    destructor destroy; override;
    function loadFromFile(s: string): boolean;
    procedure saveToFile(s: string);
  end;

implementation

uses
  lowlevelunit, dialogs;

constructor tGpxFile.create;
begin
  inherited create;
  prefix:=tMyStringList.create;
  setLength(gpx,0);
end;

destructor tGpxFile.destroy;
begin
  prefix.free;
  setLength(gpx,0);
  inherited destroy;
end;

function tGpxFile.loadFromFile(s: string): boolean;
var
  f:   tMyStringList;
  m:   longint;
  t,u: string;
begin
  result:=false;
  prefix.clear;
  setLength(gpx,0);
  f:=tMyStringList.create;
  f.loadFromFile(s);
  f.splitLines('<','>');
  m:=0;
  t:='';
  f.rewind;
  while f.readln(t) do
    case m of
      0:
        if startetMit('<gpx ',t) then begin
          setLength(gpx,length(gpx)+1);
          setLength(gpx[length(gpx)-1].trks,0);
          gpx[length(gpx)-1].kopf:=erstesArgument(t,'>');
          inc(m);
        end
        else
          prefix.add(t);
      1:
        if t='<trk>' then begin
          setLength(gpx[length(gpx)-1].trks,length(gpx[length(gpx)-1].trks)+1);
          gpx[length(gpx)-1].trks[length(gpx[length(gpx)-1].trks)-1].name:='';
          setLength(gpx[length(gpx)-1].trks[length(gpx[length(gpx)-1].trks)-1].trkPts,0);
          inc(m);
        end
        else if t='</trk>' then
          dec(m);
      2:
        if t='<name>' then begin
          t:='';
          u:='';
          repeat
            t:=t+#10+u;
            if not f.readln(u) then
              exit;
          until u='</name>';
          delete(t,1,2);
          gpx[length(gpx)-1].trks[length(gpx[length(gpx)-1].trks)-1].name:=t;
        end
        else if t='<trkseg>' then
          inc(m)
        else if t='</trkseg>' then
          dec(m);
      3:
        if startetMit('<trkpt ',t) then begin
          setLength(gpx[length(gpx)-1].trks[length(gpx[length(gpx)-1].trks)-1].trkPts,
             length(gpx[length(gpx)-1].trks[length(gpx[length(gpx)-1].trks)-1].trkPts)+1);
          with gpx[length(gpx)-1].trks[length(gpx[length(gpx)-1].trks)-1].trkPts[
               length(gpx[length(gpx)-1].trks[length(gpx[length(gpx)-1].trks)-1].trkPts)-1] do begin
            erstesArgument(t,'lat="');
            lat:=erstesArgument(t,'"');
            erstesArgument(t,'lon="');
            lon:=erstesArgument(t,'"');
            repeat
              if not f.readln(t) then
                exit;
            until t='<ele>';
            t:='';
            u:='';
            repeat
              t:=t+#10+u;
              if not f.readln(u) then
                exit;
            until u='</ele>';
            delete(t,1,2);
            ele:=t;
            repeat
              if not f.readln(t) then
                exit;
            until t='<time>';
            t:='';
            u:='';
            repeat
              t:=t+#10+u;
              if not f.readln(u) then
                exit;
            until u='</time>';
            delete(t,1,2);
            time:=t;
          end;
        end
        else if pos('</trkseg>',t)>0 then
          dec(m);
    end{of Case};
  f.free;
  result:=true;
end;

procedure tGpxFile.saveToFile(s: string);
var
  f:     textFile;
  i,j,k: longint;
begin
  assignFile(f,s);
  rewrite(f);
  writeln(f,prefix.text);
  for i:=0 to length(gpx)-1 do begin
    writeln(f,'<gpx'+gpx[i].kopf+'>');
    for j:=0 to length(gpx[i].trks)-1 do begin
      writeln(f,' <trk>');
      while pos('<',gpx[i].trks[j].name)>0 do
        gpx[i].trks[j].name[pos('<',gpx[i].trks[j].name)]:='-';
      while pos('>',gpx[i].trks[j].name)>0 do
        gpx[i].trks[j].name[pos('>',gpx[i].trks[j].name)]:='+';
      writeln(f,'  <name>'+gpx[i].trks[j].name+'</name>');
      writeln(f,'  <trkseg>');
      for k:=0 to length(gpx[i].trks[j].trkPts)-1 do begin
        writeln(f,'   <trkpt lat="'+gpx[i].trks[j].trkPts[k].lat+
                  '" lon="'+gpx[i].trks[j].trkPts[k].lon+'">');
        writeln(f,'    <ele>'+gpx[i].trks[j].trkPts[k].ele+'</ele>');
        writeln(f,'    <time>'+gpx[i].trks[j].trkPts[k].time+'</time>');
        writeln(f,'   </trkpt>');
      end;
      writeln(f,'  </trkseg>');
      writeln(f,' </trk>');
    end;
    writeln(f,'</gpx>');
  end;
  closeFile(f);
end;

end.