{  $Id$  }
{
 ***************************************************************************
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 ***************************************************************************

  Author: Vincent Snijders

  Name:
       svn2revisioninc - creates an include file with the revision number

  Synopsis:
       svn2revisioninc sourcedir revision.inc

  Description:
       svn2revisioninc creates an include file with the current revision number.

       If the source directory contains a .svn subdirectory, it tries to execute
       svnversion to get the revision number.
       If that fails - for example, because it can't find svnversion - it opens
       .svn/entries to get the revision number of the source directory.

       If it can't find revision information, it checks whether the revision.inc
       exists. If it exists and seems to be created with svn2revisioninc, it
       will leave the file as is. Otherwise it will create a new revision.inc,
       indicating that the revision number is unknown.

}
program Svn2RevisionInc;

{$mode objfpc}{$H+}

uses
  Classes, CustApp, SysUtils, Process, UTF8Process, LCLProc, FileUtil,
  Dom, XmlRead, GetOpts;

type

  { TSvn2RevisionApplication }

  TSvn2RevisionApplication = class(TCustomApplication)
  private
    SourceDirectory,
    RevisionIncFileName: string;
    RevisionIncDirName: string;
    RevisionStr: string;
    ConstName: string;
    Verbose: boolean;
    UseStdOut: boolean;

    function FindRevision: boolean;
    function IsValidRevisionInc: boolean;
    procedure WriteRevisionInc;
    function ParamsValid: boolean;
    procedure ShowHelp;
    function CanCreateRevisionInc: boolean;
    function ConstStart: string;
    procedure Show(msg: string);
  public
    constructor Create(TheOwner: TComponent); override;
    destructor Destroy; override;

    procedure Run;
  end;

var
  Application: TSvn2RevisionApplication = nil;

const
  RevisionIncComment = '// Created by Svn2RevisionInc';

function TSvn2RevisionApplication.FindRevision: boolean;
var
  SvnDir: string;
  function GetRevisionFromSvnVersion : boolean;
  var
    SvnVersionProcess: TProcessUTF8;
    Buffer: string;
    n: LongInt;
  begin
    Result:=false;
    SvnVersionProcess := TProcessUTF8.Create(nil);
    try
      with SvnVersionProcess do begin
        CommandLine := 'svnversion -n "' + SourceDirectory + '"';
        Options := [poUsePipes, poWaitOnExit];
        try
          Execute;
          SetLength(Buffer, 80);
          n:=OutPut.Read(Buffer[1], 80);
          RevisionStr := Copy(Buffer, 1, n);
          
          SetLength(Buffer, 1024);
          n:=Stderr.Read(Buffer[1], 1024);

          Result:=true;
          Show('Retrieved revision with svnversion.');
          Show('');
          Show('svnversion error:');
          Show(Copy(Buffer, 1, n));
          Show('');
        except
        // ignore error, default result is false
        end;
      end;
    finally
      SvnVersionProcess.Free;
    end;
  end;

  function GetRevisionFromEntriesTxt: boolean;
  var
    EntriesFileName: string;
    EntriesText: Text;
    line: string;
  begin
    Result:=false;
    EntriesFileName:=AppendPathDelim(SourceDirectory)+'.svn'+PathDelim+'entries';
    if FileExistsUTF8(EntriesFileName) then begin
       try
         AssignFile(EntriesText, EntriesFileName);
         Reset(EntriesText);
         try
         // skip three lines
           Readln(EntriesText, line);
           if line<>'<?xml version="1.0" encoding="utf-8"?>' then begin
             Readln(EntriesText);
             Readln(EntriesText);
             Readln(EntriesText, RevisionStr);
             Result := true;
           end;
         finally
           CloseFile(EntriesText);
         end;
       except
         // ignore error, default result is false
       end;
    end;
  end;

  function GetRevisionFromEntriesXml: boolean;
  var
    EntriesFileName: string;
    EntriesDoc: TXMLDocument;
    EntryNode: TDomNode;
  begin
    Result:=false;
    EntriesFileName:=AppendPathDelim(SourceDirectory)+'.svn'+PathDelim+'entries';
    if FileExistsUTF8(EntriesFileName) then begin
       try
         ReadXMLFile(EntriesDoc, EntriesFileName);
         try
           EntryNode := EntriesDoc.FirstChild.FirstChild;
           while not Result and (EntryNode<>nil) do begin
             if EntryNode.Attributes.GetNamedItem('name').NodeValue='' then begin
               RevisionStr:=EntryNode.Attributes.GetNamedItem('revision').NodeValue;
               Result:=true;
             end;
             EntryNode := EntryNode.NextSibling;
           end;
         finally
           EntriesDoc.Free;
         end;
       except
         // ignore error, default result is false
       end;
    end;
  end;

begin
  Result:=false;
  SvnDir:= AppendPathDelim(SourceDirectory)+'.svn';
  if DirectoryExistsUTF8(SvnDir) then
    Result := GetRevisionFromSvnVersion or GetRevisionFromEntriesTxt
      or GetRevisionFromEntriesXml;
end;

constructor TSvn2RevisionApplication.Create(TheOwner: TComponent);
begin
  inherited Create(TheOwner);
  
  RevisionStr := 'Unknown';
end;

destructor TSvn2RevisionApplication.Destroy;
begin
  inherited Destroy;
end;

function TSvn2RevisionApplication.IsValidRevisionInc: boolean;
var
  Lines: TStringList;
begin
  Result:=false;
  if FileExistsUTF8(RevisionIncFileName) then begin
    Lines := TStringList.Create;
    Lines.LoadFromFile(UTF8ToSys(RevisionIncFileName));
    if (Lines.Count=2) and
      (Lines[0]=RevisionIncComment) and
      (copy(Lines[1], 1, length(ConstStart))=ConstStart) then
      Result:=true;
  end;
end;

procedure TSvn2RevisionApplication.WriteRevisionInc;
var
  RevisionIncText: Text;
begin
  AssignFile(RevisionIncText, RevisionIncFileName);
  Rewrite(RevisionIncText);
  writeln(RevisionIncText, RevisionIncComment);
  writeln(RevisionIncText, ConstStart, RevisionStr, ''';');
  CloseFile(RevisionIncText);
  debugln(format('Created %s for revision: %s',
    [RevisionIncFileName, RevisionStr]));
end;

procedure TSvn2RevisionApplication.ShowHelp;
  function ExtractFileBaseName(FileName: string): string;
  begin
    Result := ChangeFileExt(ExtractFileName(FileName), '');
  end;
begin
  debugln;
  debugln(ParamStrUTF8(0));
  debugln;
  debugln(ExtractFileBaseName(ParamStrUTF8(0)), ' <repository path> <output file> [Options]');
  debugln('or');
  debugln(ExtractFileBaseName(ParamStrUTF8(0)), ' [Options] <repository path> <output file>');
  debugln('or');
  debugln(ExtractFileBaseName(ParamStrUTF8(0)), ' <repository path> [Options] <output file>');
  debugln;
  debugln('Options:');
  debugln(' --o                  Output file');
  debugln(' --c=<name>           Name of constant (default RevisionStr)');
  debugln(' --s                  write revision to stdout, do not create inc file');
  debugln(' --v                  Be more verbose');
  debugln(' --h                  This help screen');
  debugln;
  debugln('Note: <repository path> default current directory');
  debugln('      <output file> default revision.inc');
  debugln('      --o overrides <output file>');
  debugln;
  debugln('      1st switchless parameter = <repository path>');
  debugln('      2nd switchless parameter = <output file>');
  halt(1);
end;

function TSvn2RevisionApplication.ParamsValid: boolean;
var
  i: integer;
  index: integer;
begin
  Result := False;

  //reset
  Verbose := False;
  ConstName := 'RevisionStr';
  SourceDirectory:=ChompPathDelim(ExtractFilePath(ParamStrUTF8(0)));
  RevisionIncFileName := ExpandFileNameUTF8('revision.inc');

  //find switchless parameters
  index := 1;
  for i := 1 to ParamCount do
  begin
    if Copy(ParamStrUTF8(i),1,1) <> '-' then
    begin
      case index of
        1: SourceDirectory:=ChompPathDelim(ParamStrUTF8(i));
        2: RevisionIncFileName := ExpandFileNameUTF8(ParamStrUTF8(i));
      end;
      Inc(index);
    end;
  end;
  
  //parse options
  if HasOption('h', 'help') or HasOption('?') then
    ShowHelp;
  
  if HasOption('v') then
    Verbose := True;
    
  if HasOption('s') then
    UseStdOut := True;
    
  if HasOption('c') then
    ConstName := GetOptionValue('c');

  if HasOption('o') then
    RevisionIncFileName := GetOptionValue('o');

  //show options
  Show('SourceDirectory:     ' + SourceDirectory);
  Show('RevisionIncFileName: ' + RevisionIncFileName);
  Show('ConstName:           ' + ConstName);
  Show('');

  //checks
  if not DirectoryExistsUTF8(SourceDirectory) then
  begin
    debugln('Error: Source directory "', SourceDirectory, '" doesn''t exist.');
    exit;
  end;
  
  RevisionIncDirName:=ExtractFilePath(ExpandFileNameUTF8(RevisionIncFileName));
  if (not UseStdOut) and (not DirectoryExistsUTF8(RevisionIncDirName)) then begin
    debugln('Error: Target Directory "', RevisionIncDirName, '" doesn''t exist.');
    exit;
  end;
  
  if ConstName[1] in ['0'..'9'] then
  begin
    debugln('Error: Invalid constant name ', ConstName, '.');
    exit;
  end;
  
  Result := True;
end;

function TSvn2RevisionApplication.CanCreateRevisionInc: boolean;
begin
  if (FileExistsUTF8(RevisionIncFileName)) then
    Result:= FileIsWritable(RevisionIncFileName)
  else
    Result := DirectoryIsWritable(RevisionIncDirName);
end;

function TSvn2RevisionApplication.ConstStart: string;
begin
  Result := Format('const %s = ''', [ConstName]);
end;

procedure TSvn2RevisionApplication.Show(msg: string);
begin
  if Verbose then
    debugln(msg);
end;

procedure TSvn2RevisionApplication.Run;
begin
  if not ParamsValid then
    ShowHelp;

  if not CanCreateRevisionInc then exit;
  
  if UseStdOut then begin
    if FindRevision then
      debugln(RevisionStr);
  end
  else if FindRevision or not IsValidRevisionInc then
    WriteRevisionInc;
end;

begin
  Application := TSvn2RevisionApplication.Create(nil);
  Application.Run;
  Application.Free;
end.