/* ****************************************************************************

 *

 * Copyright (c) Microsoft Corporation. 

 *

 * This source code is subject to terms and conditions of the Microsoft Public

 * License. A  copy of the license can be found in the License.html file at the

 * root of this distribution. If  you cannot locate the  Microsoft Public

 * License, please send an email to  dlr@microsoft.com. By using this source

 * code in any fashion, you are agreeing to be bound by the terms of the 

 * Microsoft Public License.

 *

 * You must not remove this notice, or any other, from this software.

 *

 * ***************************************************************************/



using System;

using System.Collections.Generic;

using System.Text;

using System.IO;

using System.Reflection;



using System.CodeDom;

using System.CodeDom.Compiler;



using IronPython.Compiler;

using IronPython.Compiler.Ast;

using IronPython.Runtime;

using System.Diagnostics;



namespace IronPython.CodeDom {

    class PythonParser : CodeParser, IDisposable {

        private List<string> references = new List<string>();

        private SystemState state = new SystemState();



        public PythonParser(List<string> assemblyReferences) {

            if (assemblyReferences.Count == 0) {

                references.Add("System.Windows.Forms");

                references.Add("System");

                references.Add("System.Data");

                references.Add("System.Drawing");

                references.Add("System.Xml");

                references.Add("mscorlib");

            } else {

                references.AddRange(assemblyReferences);

            }

        }



        /// <summary>

        /// Parse an entire file - ideal path as we'll respect

        /// PEP-263 encodings and the such...

        /// </summary>

        public CodeCompileUnit ParseFile(string filename) {

            return Parse(Parser.FromFile(state, new CompilerContext(filename)), filename);

        }



        /// <summary>

        /// Parse an arbitrary stream

        /// </summary>

        public override CodeCompileUnit Parse(System.IO.TextReader codeStream) {

            return ParseMergeable(codeStream, null);

        }



        public CodeCompileUnit ParseMergeable(string text, string filename, IMergeDestination destination){

            CodeCompileUnit tree = Parse(Parser.FromString(state, new CompilerContext(), text), filename);



            CodeMerger.CacheCode(tree, destination);

            return tree;

        }



        public CodeCompileUnit ParseMergeable(System.IO.TextReader codeStream, IMergeDestination destination) {

            // get a better filename if we can

            string name = "<unknown>";

            StreamReader sw = codeStream as StreamReader;

            if (sw != null) {

                FileStream fs = sw.BaseStream as FileStream;

                if (fs != null) name = fs.Name;

            }

            //!!! it'd be nice to have Parser.FromStream to get proper decodings here            

            string codeText = codeStream.ReadToEnd();

            CodeCompileUnit tree = Parse(Parser.FromString(state, new CompilerContext(), codeText), name);



            if (destination != null) CodeMerger.CacheCode(tree, destination);

            else CodeMerger.CacheCode(tree, codeText);



            return tree;

        }



        /// <summary>

        /// Parses an arbitrary string of Python code

        /// </summary>

        public CodeCompileUnit Parse(string text) {

            return Parse(Parser.FromString(state, new CompilerContext(), text), "<unknown>");

        }



        /// <summary>

        /// Private helper function for all parsing.  Takes in the IronPython Parser 

        /// object and a filename that's used for error reports

        /// </summary>

        /// <param name="p"></param>

        private CodeCompileUnit Parse(Parser p, string filename) {



            Statement s = p.ParseFileInput();

            CodeCompileUnit res = new CodeCompileUnit();

            CodeNamespace defaultNamespace = new CodeNamespace();

            defaultNamespace.UserData["Line"] = 1;

            defaultNamespace.UserData["Column"] = 1;

            defaultNamespace.UserData["EndLine"] = 1;

            defaultNamespace.UserData["EndColumn"] = 1;



            //!!! enable AD usage when we're strong named.

            //AppDomainSetup ads = new AppDomainSetup();

            //ads.ApplicationBase = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);

            //AppDomain ad = AppDomain.CreateDomain("ParserReferenceDomain",null,ads);

            try {

                RemoteReferences rc = new RemoteReferences();

                /*(RemoteReferences)ad.CreateInstanceAndUnwrap(

                                Assembly.GetExecutingAssembly().FullName,

                                "IronPython.CodeDom.RemoteReferences");*/

                rc.Initialize(references);





                CodeWalker cw = new CodeWalker(filename, rc);

                s.Walk(cw);



                CodeObject co = cw.LastObject;

                CodeObjectSuite cos = co as CodeObjectSuite;

                if (cos == null) cos = new CodeObjectSuite(new CodeObject[] { co });



                // walk the top-level and see if we need to create a fake top-type

                // or if we can just stick everything directly into the namespace.

                CodeTypeDeclaration topType = null;

                for (int i = 0; i < cos.Count; i++) {

                    topType = CheckTopLevel(cos[i], res, defaultNamespace, topType);

                }



                // if no namespaces we're added then everything's in our default namespace.

                if (res.Namespaces.Count == 0 || defaultNamespace.Types.Count > 0) {

                    res.Namespaces.Add(defaultNamespace);

                }



                UpdateTopType(topType, defaultNamespace);

            } finally {

                //AppDomain.Unload(ad);

            }



            return res;

        }



        private static CodeTypeDeclaration CheckTopLevel(CodeObject cur, CodeCompileUnit res, CodeNamespace defaultNamespace, CodeTypeDeclaration topType) {

            if (cur is CodeNamespaceImport) {

                CodeNamespaceImport adding = cur as CodeNamespaceImport;

                foreach (CodeNamespaceImport cni in defaultNamespace.Imports) {

                    if (cni.Namespace == adding.Namespace) {

                        cni.UserData["Dupped"] = true;

                        return topType;

                    }

                }

                defaultNamespace.Imports.Add(adding);

            } else if (cur is CodeTypeDeclaration) {

                CodeTypeDeclaration ctd = cur as CodeTypeDeclaration;

                bool fRealClass = false;

                if (ctd.BaseTypes.Count == 0) {

                    foreach (CodeTypeMember mem in ctd.Members) {

                        if (mem is CodeTypeDeclaration)

                            continue;



                        fRealClass = true;

                        break;

                    }

                } else {

                    fRealClass = true;

                }



                if (fRealClass) {

                    defaultNamespace.Types.Add(ctd);

                } else {

                    // class w/ nested types, transfer the

                    // type's content to a namespace.

                    TypeToNamespace(res, defaultNamespace, ctd);

                }

            } else if (cur is CodeNamespace) {

                res.Namespaces.Add(cur as CodeNamespace);

            } else if (cur is CodeExpressionStatement) {

                ValidateCodeExpression(cur as CodeExpressionStatement);

            } else {

                if (topType == null) topType = new CodeTypeDeclaration("__top__");

                topType.Members.Add((CodeTypeMember)cur);

            }

            return topType;

        }



        private static void TypeToNamespace(CodeCompileUnit res, CodeNamespace defaultNamespace, CodeTypeDeclaration ctd) {

            CodeNamespace nsRes = new CodeNamespace(ctd.Name);

            res.Namespaces.Add(nsRes);



            foreach (CodeTypeMember mem in ctd.Members) {

                nsRes.Types.Add((CodeTypeDeclaration)mem);

            }



            CopyLineInfo(ctd, nsRes);



            foreach (CodeNamespaceImport cn in defaultNamespace.Imports) {

                nsRes.Imports.Add(cn);

            }            

        }



        private static void CopyLineInfo(CodeTypeDeclaration ctd, CodeNamespace nsRes) {

            nsRes.UserData["PreImport"] = true;

            nsRes.UserData["IPCreated"] = ctd.UserData["IPCreated"];

            nsRes.UserData["EndLine"] = ctd.UserData["EndLine"];

            nsRes.UserData["EndColumn"] = ctd.UserData["EndColumn"];

            nsRes.UserData["Column"] = ctd.UserData["Column"];

            nsRes.UserData["Line"] = ctd.UserData["Line"];

        }



        private static void UpdateTopType(CodeTypeDeclaration topType, CodeNamespace defaultNamespace) {

            if (topType != null) {

                // we had a non-type at the top-level, we need to transfer

                // all our types from the default name space to the top-type

                for (int i = 0; i < defaultNamespace.Types.Count; i++) {

                    topType.Members.Insert(i, defaultNamespace.Types[i]);

                }



                defaultNamespace.Types.Clear();



                topType.UserData["IsTopType"] = true;

            }

        }



        private static void ValidateCodeExpression(CodeExpressionStatement ces) {

            CodeMethodInvokeExpression invoke = ces.Expression as CodeMethodInvokeExpression;

            if (invoke != null) {

                CodeFieldReferenceExpression target = invoke.Method.TargetObject as CodeFieldReferenceExpression;

                if (target != null) {

                    if (target.FieldName != "RealEntryPoint") throw new NotImplementedException("arbitrary calls at the top-level");

                } else if (invoke.Method.MethodName != "RealEntryPoint") throw new NotImplementedException("arbitrary calls at the top-level");



                // otherwise we want to ignore the statement.

            } else {

                throw new NotImplementedException("arbitrary expressions at the top-level");

            }

        }



        ~PythonParser() {

            Dispose(true);

        }



        #region IDisposable Members



        public void Dispose() {

            Dispose(false);

        }



        #endregion



        private void Dispose(bool finalizing) {

            // if we're finalizing we shouldn't access other managed objects, as

            // their finalizers may have already run            

            if (!finalizing) {

                state.Dispose();

            }

        }

    }





    class CodeObjectSuite : CodeObject {

        List<CodeObject> objects = new List<CodeObject>();



        public CodeObjectSuite() {

        }



        public CodeObjectSuite(CodeObject[] objs) {

            objects.AddRange(objs);

        }



        public int Count {

            get {

                return objects.Count;

            }

        }



        public CodeObject this[int index] {

            get {

                return objects[index];

            }

            set {

                objects[index] = value;

            }

        }



        public void Add(CodeObject co) {

            objects.Add(co);

        }



        public void RemoveAt(int index) {

            objects.RemoveAt(index);

        }

    }

}