const z = @import( "std" );
const zap = @import( "zap" );
const net = @import( "net-util.zig" );
const json = @import( "json" );
const getty = @import( "getty" );

const ArenaAllocator = z.heap.ArenaAllocator;
const GettyResult = getty.de.Result;
pub var gpa = z.heap.GeneralPurposeAllocator( .{ .thread_safe = true, .stack_trace_frames = 64 } ){};
pub const alloc = gpa.allocator();

const Status = zap.StatusCode;
const Request = zap.Request;

const pbkdf2 = z.crypto.pwhash.pbkdf2;

const aes256Encrypt = z.crypto.aead.aes_gcm.Aes256Gcm.encrypt;
const aes256Decrypt = z.crypto.aead.aes_gcm.Aes256Gcm.decrypt;

pub const @"json.ignore.unknown" = struct {
  pub const attributes = .{
    .Container = .{ .ignore_unknown_fields = true },
  };
};

pub fn MergeTypes( comptime t1: type, comptime t2: type ) type {
  const t1info = @typeInfo( t1 ).Struct;
  const t2info = @typeInfo( t2 ).Struct;

  comptime if( t1info.is_tuple ) return t2;
  comptime if( t2info.is_tuple ) return t1;

  var t3info = t1info;
  t3info.fields = t1info.fields ++ t2info.fields;

  var t1s = @typeInfo( t1 );
  t1s.Struct = t3info;

  return @Type( t1s );
}

pub fn JsonResponse( comptime t: type ) type {
   return struct {
    v: t,
    @"#alloc": ArenaAllocator,
    pub fn deinit( self: @This() ) void {
      self.@"#alloc".deinit();
    }
  };
}

///freed by caller
pub fn jsonParse( comptime t: type, str: []const u8 ) !JsonResponse(t) {
  return jsonParseAlloc( t, str, alloc );
}

///freed by caller
pub fn jsonParseAlloc( comptime t: type, str: []const u8, a: z.mem.Allocator ) !JsonResponse(t) {
  var arena = ArenaAllocator.init( a );
  const allocator = arena.allocator();

  const ret = json.fromSlice( allocator, t, str ) catch |e| {
    arena.deinit();
    return e;
  };
  var obj: JsonResponse(t) = undefined;
  obj.v = ret.value;
  obj.@"#alloc" = arena;

  return obj;
}

///has to be freed using page_allocator
pub fn jsonStringify( obj: anytype ) ![]const u8 {
  var arr = z.ArrayList( u8 ).init( alloc );
  try json.toWriter( alloc, obj, arr.writer() );
  return arr.toOwnedSlice();
}

pub fn jsonStringifyAlloc( obj: anytype, a: z.mem.Allocator ) ![]const u8 {
  var arr = z.ArrayList( u8 ).init( a );
  try json.toWriter( alloc, obj, arr.writer() );
  return arr.toOwnedSlice();
}

///has to be freed by caller with page_allocator
///10mb max
pub fn readFile( path: []const u8 ) ![]const u8 {
  return readFileAlloc( path, alloc );
}

pub fn readFileAlloc( path: []const u8, a: z.mem.Allocator ) ![]const u8 {
  const file = try z.fs.cwd().openFile( path, .{} );
  defer file.close();

  var reader = z.io.bufferedReader( file.reader() );
  var stream = reader.reader();

  const contents = try stream.readAllAlloc( a, 1024 * 10000 );
  return contents[0..contents.len];
}

pub fn fileExists( path: []const u8 ) bool {
  const file = z.fs.cwd().openFile( path, .{} ) catch return false;
  _ = file.stat() catch return false;
  file.close();

  return true;
}

pub fn writeFile( path: []const u8, contents: []const u8 ) !void {
  z.fs.cwd().deleteFile( path ) catch |e| {
    switch (e) {
      error.FileNotFound => {},
      else => return e
    }
  };
  const file = try z.fs.cwd().createFile( path, .{} );
  defer file.close();

  var writer = file.writer();
  writer.writeAll( contents ) catch return error.OutOfMemory;
}

pub fn deleteFile( path: []const u8 ) !void {
  z.fs.cwd().deleteFile( path ) catch |e| {
    switch (e) {
      error.FileNotFound => {},
      else => return e
    }
  };
}

pub fn hexToBytesAlloc( hex: []const u8, a: z.mem.Allocator ) ![]const u8 {
  var bytes = try a.alloc( u8, hex.len / 2 );
  var i: u32 = 0;
  while( i < hex.len ) : (i += 2) {
    z.debug.print( "byte: {s}\n", .{ hex[i..i+1] } );
    const byte = try z.fmt.parseInt( u8, hex[i..i+1], 16 );
    bytes[i/2] = byte;
  }

  return bytes;
}

pub fn hexToBytes( hex: []const u8 ) ![]const u8 {
  return hexToBytesAlloc( hex, alloc );
}

///EXTREMELY GAY but zig crypto lib has a bug that makes it not compile.
///IMPORTANT: FIX THIS!!!!!
pub fn readFileCrypto( path: []const u8 ) ![]const u8 {
  const proc = try z.process.Child.run( .{
    .allocator = alloc,
    .argv = &.{ "node", "../chat-reader.cjs", "read", path }
  } );
  defer alloc.free( proc.stdout );
  defer alloc.free( proc.stderr );

  if( proc.stdout[0] == '0' )
    return error.FileNotFound;

  const buf = alloc.dupe( u8, proc.stdout );
  return buf;
}

pub fn writeFileCrypto( path: []const u8, buf: []const u8 ) ![]const u8 {
  const proc = try z.process.Child.run( .{
    .allocator = alloc,
    .argv = &.{ "node", "../chat-reader.cjs", "write", path, buf }
  } );
  defer alloc.free( proc.stdout );
  defer alloc.free( proc.stderr );

  const ret = alloc.dupe( u8, proc.stdout );
  return ret;
}

pub const Validator = struct {
  pub fn isValidChar( c: u8 ) bool {
    if( c >= 'a' and c <= 'z' )
      return true;
    if( c >= 'A' and c <= 'Z' )
      return true;
    if( c >= '0' and c <= '9' )
      return true;
    if( c == '-' or c == '_' )
      return true;
    if( c == '.' )
      return true;
    if( c == '@' )
      return true;

    return false;
  }

  pub fn isValidCharSystem( c: u8 ) bool {
    const allowlist = ",;:/?=!#$^&*()+~[]{}<>|` ";
    for( allowlist ) |allowc| {
      if( allowc == c )
        return true;
    }

    return isValidChar( c );
  }

  pub fn isValidCharFont( c: u8 ) bool {
    if( c == ' ' )
      return true;
    if( !isValidChar( c ) )
      return false;
    return true;
  }

  pub fn isValidCharEmail( c: u8 ) bool {
    if( !isValidChar( c ) )
      return false;
    return true;
  }

  pub fn isValidStrSystem( str: []const u8 ) bool {
    if( str.len > 2048 )
      return false;
    for( str ) |c| {
      if( !isValidCharSystem( c ) )
        return false;
    }
    return true;
  }

  pub fn isValidStrNickname( str: []const u8 ) bool {
    if( str.len > 24 )
      return false;
    if( str.len < 2 )
      return false;
    for( str ) |c| {
      if( !isValidCharEmail( c ) )
        return false;
    }
    return true;
  }

  pub fn isValidStrEmail( str: []const u8 ) bool {
    if( str.len > 127 )
      return false;
    if( str.len < 5 )
      return false;
    var has_at = false;
    var has_dot = false;
    for( str ) |c| {
      if( !isValidCharEmail( c ) )
        return false;

      if( c == '@' ) has_at = true;
      if( c == '.' ) has_dot = true;
    }
    return true;
  }

  pub fn isValidStrFont( str: []const u8 ) bool {
    if( str.len > 64 )
      return false;
    if( str.len < 3 )
      return false;
    for( str ) |c| {
      if( !isValidCharFont( c ) )
        return false;
    }
    return true;
  }
};