//import win32 ( WIN32_FIND_DATAA, FindFirst )

import win32;
import libc;
import io.paths;

Private stream printWithSprintf: formatString, value [
    var buf = Array[CChar, 100]: ;
    libc.sprintf: &buf[0], (cstring: formatString), value;
    var n = libc.strlen: &buf[0];
    var ptr = Pointer[Byte]: &buf[0];
    stream write: ptr, (SizeT: n);
];

Private record FileDirectory[S] (
    S path,
);


direntSequence('T x) [String?('T)] = [ FileDirectory['T]: x ];


iterator(FileDirectory['T] x) [String?(T)] = [ FileIterator: x.path ];


private: record FileIterator (
    win32.HANDLE handle,
    Bool queued?,
    win32.WIN32_FIND_DATAA findData,
);

private: record FileInfo (
    String name,
    Bool system?,
    Bool directory?,
);


FileIterator: 'T path [String?('T)] = FileIterator self [
    self.handle = win32.FindFirstFileA: (cstring: path), &self.findData;
    self.queued? = true;
    return self;
];

overload destroy: FileIterator x [
    win32.FindClose(x.handle);
];

overload hasNext?(x:FileIterator) [
    if: (not: x.queued?) then: [
        x.queued? = true;
        
        var returnCode = win32.FindNextFileA: x.handle, &x.findData;
        return (returnCode != 0);
    ]
    else:
        [ return true; ];
];

flags testFlag: flag = [ (flags bitwiseAnd: flag) == flag ];

next FileIterator x [
    if: (not: x.queued?)
        then: [ hasNext?: x; ]
    x.queued? = false;
    return FileInfo:
        String: (CStringRef: (begin: x.findData.cFileName)),
        (testFlag: x.findData.dwFileAttributes, win32.FILE_ATTRIBUTE_SYSTEM),
        (testFlag: x.findData.dwFileAttributes, win32.FILE_ATTRIBUTE_DIRECTORY)
    ;
];

subtract: Char a, Char b
[  
    return (Int: a)-(Int: b);
];

hexToInt: string
[
    var number = 0;
    for: string each:
    [ char ->
        if: (char >= '0' and: char <= '9')
        then: [ number = number * 16 + (char - '0'); ]
        else: [ 
            if: (char >= 'A' and char <= 'F')
            then [ number = number * 16 + (char - 'A' + 10); ]
            else: [ return (false, 0); ];
        ];
    ];
    return (true, number);
];

errorMsg: msg
[
    println: msg;
    flush: stdin;
    var buff = Array[Byte,1]: ;
    stdin read: (begin: buff), 1;
];

renameFile: a, b
[
    win32.MoveFileA: (cstring: a), (cstring: b);
];

massren:
[
    var files = Vector[String]: ;
    var dir = FileDirectory: "*";
    for: dir each:
    [ fi ->
        if (and: (not: fi.system?), (not fi.directory?),
            (fi.name != "massren.exe"),
            (and fi.name != "massren.txt"))
        then: [ files push: fi.name; ];
    ];
    
    sort: files;
    
    if: (not: (io.paths.pathExists?: "massren.txt"))
    then: [
        println: "listing...";
        var configFile = File: "massren.txt", CREATE;
        
        configFile printWithSprintf: "massren file -- directory hash: %8.0X\n", (hash: files);
        for: files each:
            [ f -> printlnTo: configFile, f; ];
            
        println: "done !";
    ]
    else:
    [
        var configFile = File: "massren.txt", READ;
        var header = readLine: configFile;
//        print: header;
        var hashString = slicedFrom: (trimmed: header), (size: "massren file -- directory hash: ");
        var ok, hash = ...unpack: (hexToInt: hashString);
        if: (ok and: hash == (prelude.hash: files))
        then: [
            println: "testing...";
            
            var filesFrom = files;
            var filesTo = Vector[String]: ;
            for: files each:
            [ nameFrom ->
                push(filesTo, trim(readLine(configFile)));
            ];   
            print: filesTo;
            println: "renaming (1/2)...";
            for: (zipped: filesFrom, filesTo) each:
            [ nameFrom, nameTo ->
               // println(nameFrom, " -> " ,"massren_temp_"+nameFrom);
                renameFile(nameFrom, "massren_temp_"+nameFrom);
            ];
            println: "renaming (2/2)...";
            for: (zipped: filesFrom, filesTo) each:
            [ nameFrom, nameTo ->
              //  println: "massren_temp_"+nameFrom, " -> " ,nameTo;
                renameFile: "massren_temp_"+nameFrom, nameTo;
            ];
            println: "done !";
        ] else: 
        [
            errorMsg("directory hash mismatch !");
            
        ];
    ];
];

main:
[
    //stdout printWithSprintf: "massren file -- directory hash: %0.8X\n", 1;
    massren: ;
];