diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..0cc7023
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "msgpack-d"]
+	path = msgpack-d
+	url = https://github.com/msgpack/msgpack-d.git
diff --git a/autocomplete.d b/autocomplete.d
new file mode 100644
index 0000000..59fa457
--- /dev/null
+++ b/autocomplete.d
@@ -0,0 +1,68 @@
+module autocomplete;
+
+import std.array;
+import std.stdio;
+import std.d.lexer;
+import std.d.parser;
+import std.d.ast;
+import std.range;
+
+import messages;
+import importutils;
+import constants;
+
+AutocompleteResponse complete(AutocompleteRequest request, string[] importPaths)
+{
+    writeln("Got a completion request");
+    AutocompleteResponse response;
+
+    LexerConfig config;
+    auto tokens = request.sourceCode.byToken(config);
+    auto tokenArray = tokens.array();
+    auto sortedTokens = assumeSorted(tokenArray);
+
+    auto beforeTokens = sortedTokens.lowerBound(cast(size_t) request.cursorPosition);
+    if (beforeTokens[$ - 1] ==  TokenType.lParen)
+    {
+        if (beforeTokens[$ - 2] == TokenType.traits)
+        {
+            response.completionType = CompletionType.identifiers;
+            for (size_t i = 0; i < traits.length; i++)
+            {
+                response.completions ~= traits[i];
+                response.completionKinds ~= CompletionKind.keyword;
+            }
+        }
+        else if (beforeTokens[$ - 2] == TokenType.scope_)
+        {
+            response.completionType = CompletionType.identifiers;
+            for (size_t i = 0; i < scopes.length; i++)
+            {
+                response.completions ~= scopes[i];
+                response.completionKinds ~= CompletionKind.keyword;
+            }
+        }
+        else if (beforeTokens[$ - 2] == TokenType.version_)
+        {
+            response.completionType = CompletionType.identifiers;
+            for (size_t i = 0; i < versions.length; i++)
+            {
+                response.completions ~= versions[i];
+                response.completionKinds ~= CompletionKind.keyword;
+            }
+        }
+    }
+    else
+    {
+        Module mod = parseModule(tokenArray, request.fileName, &messageFunction);
+
+        writeln("Resolved imports: ", getImportedFiles(mod, importPaths ~ request.importPaths));
+    }
+
+    return response;
+}
+
+void messageFunction(string fileName, int line, int column, string message)
+{
+    // does nothing
+}
diff --git a/build.sh b/build.sh
new file mode 100755
index 0000000..ab4a88b
--- /dev/null
+++ b/build.sh
@@ -0,0 +1,2 @@
+dmd client.d messages.d msgpack-d/src/msgpack.d -Imsgpack-d/src -ofdcd-client
+dmd server.d messages.d constants.d importutils.d autocomplete.d ../dscanner/std/d/ast.d ../dscanner/std/d/parser.d ../dscanner/std/d/lexer.d ../dscanner/std/d/entities.d msgpack-d/src/msgpack.d -Imsgpack-d/src -I../dscanner/ -ofdcd-server
diff --git a/client.d b/client.d
new file mode 100644
index 0000000..e472cf9
--- /dev/null
+++ b/client.d
@@ -0,0 +1,123 @@
+module client;
+
+import std.socket;
+import std.stdio;
+import std.getopt;
+import std.array;
+
+import msgpack;
+import messages;
+
+int main(string[] args)
+{
+    int cursorPos = -1;
+    string[] importPaths;
+    ushort port = 9090;
+    bool help;
+
+    try
+    {
+        getopt(args, "cursorPos|c", &cursorPos, "I", &importPaths,
+            "port|p", &port, "help|h", &help);
+    }
+    catch (Exception e)
+    {
+        stderr.writeln(e.msg);
+    }
+
+    if (help)
+    {
+        printHelp(args[0]);
+        return 0;
+    }
+
+    // cursor position is a required argument
+    if (cursorPos == -1)
+    {
+        printHelp(args[0]);
+        return 1;
+    }
+
+    // Read in the source
+    bool usingStdin = args.length <= 1;
+    string fileName = usingStdin ? "stdin" : args[1];
+    File f = usingStdin ? stdin : File(args[1]);
+    ubyte[] sourceCode = usingStdin ? cast(ubyte[]) [] : uninitializedArray!(ubyte[])(f.size);
+    f.rawRead(sourceCode);
+
+    // Create message
+    AutocompleteRequest request;
+    request.fileName = fileName;
+    request.importPaths = importPaths;
+    request.sourceCode = sourceCode;
+    request.cursorPosition = cursorPos;
+    ubyte[] message = msgpack.pack(request);
+
+    // Send message to server
+    auto socket = new TcpSocket(AddressFamily.INET);
+    scope (exit) socket.close();
+    socket.connect(new InternetAddress("127.0.0.1", port));
+    socket.blocking = true;
+    stderr.writeln("Sending ", message.length, " bytes");
+    auto bytesSent = socket.send(message);
+    stderr.writeln(bytesSent, " bytes sent");
+
+    // Get response and write it out
+    ubyte[1024 * 16] buffer;
+    auto bytesReceived = socket.receive(buffer);
+    if (bytesReceived == Socket.ERROR)
+    {
+        return 1;
+    }
+
+    AutocompleteResponse response;
+    msgpack.unpack(buffer[0..bytesReceived], response);
+
+    writeln(response.completionType);
+    if (response.completionType == CompletionType.identifiers)
+    {
+        for (size_t i = 0; i < response.completions.length; i++)
+        {
+            writefln("%s\t%s", response.completions[i], response.completionKinds[i]);
+        }
+    }
+    else
+    {
+        foreach (completion; response.completions)
+        {
+            writeln(completion);
+        }
+    }
+    stderr.writeln("completed");
+    return 0;
+}
+
+void printHelp(string programName)
+{
+    writefln(
+`
+    Usage: %1$s --cursorPos NUMBER [options] [FILENAME]
+       or: %1$s -cNUMBER [options] [FILENAME]
+
+    A file name is optional. If it is given, autocomplete information will be
+    given for the file specified. If it is missing, input will be read from
+    stdin instead.
+
+    Source code is assumed to be UTF-8 encoded.
+
+Mandatory Arguments:
+    --cursorPos | -c position
+        Provides auto-completion at the given cursor position. The cursor
+        position is measured in bytes from the beginning of the source code.
+
+Options:
+    --help | -h
+        Displays this help message
+
+    -IPATH
+        Includes PATH in the listing of paths that are searched for file imports
+
+    --port PORTNUMBER | -pPORTNUMBER
+        Uses PORTNUMBER to communicate with the server instead of the default
+        port 9091.`, programName);
+}
diff --git a/constants.d b/constants.d
new file mode 100644
index 0000000..222331d
--- /dev/null
+++ b/constants.d
@@ -0,0 +1,130 @@
+module constants;
+
+immutable string[] traits = [
+    "allMembers",
+    "classInstanceSize",
+    "compiles"
+    "derivedMembers",
+    "getAttributes",
+    "getMember",
+    "getOverloads",
+    "getProtection",
+    "getVirtualFunctions",
+    "getVirtualMethods",
+    "hasMember",
+    "identifier",
+    "isAbstractClass",
+    "isAbstractFunction",
+    "isArithmetic",
+    "isAssociativeArray",
+    "isFinalClass",
+    "isFinalFunction",
+    "isFloating",
+    "isIntegral",
+    "isLazy",
+    "isNested",
+    "isOut",
+    "isPOD",
+    "isRef",
+    "isSame",
+    "isScalar",
+    "isStaticArray",
+    "isStaticFunction",
+    "isUnsigned",
+    "isVirtualFunction",
+    "isVirtualMethod",
+    "parent"
+];
+
+/**
+ * Scope conditions
+ */
+immutable string[] scopes = [
+    "exit",
+    "failure",
+    "success"
+];
+
+/**
+ * Predefined version identifiers
+ */
+immutable string[] versions = [
+    "AArch64",
+    "AIX",
+    "all",
+    "Alpha",
+    "Alpha_HardFloat",
+    "Alpha_SoftFloat",
+    "Android",
+    "ARM",
+    "ARM_HardFloat",
+    "ARM_SoftFloat",
+    "ARM_SoftFP",
+    "ARM_Thumb",
+    "assert",
+    "BigEndian",
+    "BSD",
+    "Cygwin",
+    "D_Coverage",
+    "D_Ddoc",
+    "D_HardFloat",
+    "DigitalMars",
+    "D_InlineAsm_X86",
+    "D_InlineAsm_X86_64",
+    "D_LP64",
+    "D_NoBoundsChecks",
+    "D_PIC",
+    "DragonFlyBSD",
+    "D_SIMD",
+    "D_SoftFloat",
+    "D_Version2",
+    "D_X32",
+    "FreeBSD",
+    "GNU",
+    "Haiku",
+    "HPPA",
+    "HPPA64",
+    "Hurd",
+    "IA64",
+    "LDC",
+    "linux",
+    "LittleEndian",
+    "MIPS32",
+    "MIPS64",
+    "MIPS_EABI",
+    "MIPS_HardFloat",
+    "MIPS_N32",
+    "MIPS_N64",
+    "MIPS_O32",
+    "MIPS_O64",
+    "MIPS_SoftFloat",
+    "NetBSD",
+    "none",
+    "OpenBSD",
+    "OSX",
+    "Posix",
+    "PPC",
+    "PPC64",
+    "PPC_HardFloat",
+    "PPC_SoftFloat",
+    "S390",
+    "S390X",
+    "SDC",
+    "SH",
+    "SH64",
+    "SkyOS",
+    "Solaris",
+    "SPARC",
+    "SPARC64",
+    "SPARC_HardFloat",
+    "SPARC_SoftFloat",
+    "SPARC_V8Plus",
+    "SysV3",
+    "SysV4",
+    "unittest",
+    "Win32",
+    "Win64",
+    "Windows",
+    "X86",
+    "X86_64",
+];
diff --git a/importutils.d b/importutils.d
new file mode 100644
index 0000000..caa9a2f
--- /dev/null
+++ b/importutils.d
@@ -0,0 +1,71 @@
+module importutils;
+
+import std.file;
+import std.d.parser;
+import std.d.ast;
+import std.stdio;
+
+class ImportCollector : ASTVisitor
+{
+    alias ASTVisitor.visit visit;
+
+    override void visit(ImportDeclaration dec)
+    {
+        foreach (singleImport; dec.singleImports)
+        {
+            imports ~= flattenIdentifierChain(singleImport.identifierChain);
+        }
+        if (dec.importBindings !is null)
+        {
+            imports ~= flattenIdentifierChain(dec.importBindings.singleImport.identifierChain);
+        }
+    }
+
+    private static string flattenIdentifierChain(IdentifierChain chain)
+    {
+        string rVal;
+        bool first = true;
+        foreach (identifier; chain.identifiers)
+        {
+            if (!first)
+                rVal ~= "/";
+            rVal ~= identifier.value;
+            first = false;
+        }
+        rVal ~= ".d";
+        return rVal;
+    }
+
+    string[] imports;
+}
+
+string[] getImportedFiles(Module mod, string[] importPaths)
+{
+    auto collector = new ImportCollector;
+    collector.visit(mod);
+    string[] importedFiles;
+    foreach (imp; collector.imports)
+    {
+        bool found = false;
+        foreach (path; importPaths)
+        {
+            string filePath = path ~ "/" ~ imp;
+            if (filePath.exists())
+            {
+                importedFiles ~= filePath;
+                found = true;
+                break;
+            }
+            filePath ~= "i"; // check for x.di if x.d isn't found
+            if (filePath.exists())
+            {
+                importedFiles ~= filePath;
+                found = true;
+                break;
+            }
+        }
+        if (!found)
+            writeln("Could not locate ", imp);
+    }
+    return importedFiles;
+}
diff --git a/messages.d b/messages.d
new file mode 100644
index 0000000..fa172a0
--- /dev/null
+++ b/messages.d
@@ -0,0 +1,102 @@
+module messages;
+
+/**
+ * Identifies the kind of the item in an identifier completion list
+ */
+enum CompletionKind : char
+{
+    /// class names
+    className = 'c',
+
+    /// interface names
+    interfaceName = 'i',
+
+    /// structure names
+    structName = 's',
+
+    /// variable name
+    variableName = 'v',
+
+    /// member variable
+    memberVariableName = 'm',
+
+    /// keyword, built-in version, scope statement
+    keyword = 'k',
+
+    /// function or method
+    functionName = 'f',
+
+    /// enum name
+    enumName = 'g',
+
+    /// package name
+    packageName = 'P',
+
+    // module name
+    moduleName = 'M'
+}
+
+/**
+ * The type of completion list being returned
+ */
+enum CompletionType : string
+{
+    /**
+     * The completion list contains a listing of identifier/kind pairs.
+     */
+    identifiers = "identifiers",
+
+    /**
+     * The auto-completion list consists of a listing of functions and their
+     * parameters.
+     */
+    calltips = "calltips"
+}
+
+/**
+ * Autocompletion request message
+ */
+struct AutocompleteRequest
+{
+    /**
+     * File name used for error reporting
+     */
+    string fileName;
+
+    /**
+     * Paths to be searched for import files
+     */
+    string[] importPaths;
+
+    /**
+     * The source code to auto complete
+     */
+    ubyte[] sourceCode;
+
+    /**
+     * The cursor position
+     */
+    int cursorPosition;
+}
+
+/**
+ * Autocompletion response message
+ */
+struct AutocompleteResponse
+{
+    /**
+     * The autocompletion type. (Parameters or identifier)
+     */
+    string completionType;
+
+    /**
+     * The completions
+     */
+    string[] completions;
+
+    /**
+     * The kinds of the items in the completions array. Will be empty if the
+     * completion type is a function argument list.
+     */
+    char[] completionKinds;
+}
diff --git a/msgpack-d b/msgpack-d
new file mode 160000
index 0000000..40c797c
--- /dev/null
+++ b/msgpack-d
@@ -0,0 +1 @@
+Subproject commit 40c797cb8ae3eb56cf88399ef3532fc29abd238a
diff --git a/server.d b/server.d
new file mode 100644
index 0000000..2202af3
--- /dev/null
+++ b/server.d
@@ -0,0 +1,69 @@
+module server;
+
+import std.socket;
+import std.stdio;
+import std.getopt;
+
+import msgpack;
+
+import messages;
+import autocomplete;
+
+void main(string[] args)
+{
+    ushort port = 9090;
+    bool help;
+    string[] importPaths;
+
+    try
+    {
+        getopt(args, "port|p", &port, "I", &importPaths, "help|h", &help);
+    }
+    catch (Exception e)
+    {
+        stderr.writeln(e.msg);
+    }
+
+    auto socket = new TcpSocket(AddressFamily.INET);
+    socket.blocking = true;
+    socket.bind(new InternetAddress("127.0.0.1", port));
+    socket.listen(0);
+    scope (exit) socket.close();
+    ubyte[1024 * 1024 * 4] buffer = void; // 4 megabytes should be enough for anybody...
+    while (true)
+    {
+        auto s = socket.accept();
+        s.blocking = true;
+        scope (exit) s.close();
+        ptrdiff_t bytesReceived = s.receive(buffer);
+
+        if (bytesReceived == Socket.ERROR)
+        {
+            writeln("Socket recieve failed");
+            break;
+        }
+        else
+        {
+            AutocompleteRequest request;
+            writeln("Unpacking ", bytesReceived, "/", buffer.length, " bytes into a request");
+            msgpack.unpack(buffer[0 .. bytesReceived], request);
+            AutocompleteResponse response = complete(request, importPaths);
+            ubyte[] responseBytes = msgpack.pack(response);
+            assert(s.send(responseBytes) == responseBytes.length);
+        }
+    }
+}
+
+void printHelp(string programName)
+{
+    writefln(
+`
+    Usage: %s options
+
+options:
+    -I path
+        Includes path in the listing of paths that are searched for file imports
+
+    --port PORTNUMBER | -pPORTNUMBER
+        Listens on PORTNUMBER instead of the default port 9091.`, programName);
+}