/*******************************************************************************
 *  Copyright (c) 2010 Association for Decentralized Information Management in
 *  Industry THTH ry.
 *  All rights reserved. This program and the accompanying materials
 *  are made available under the terms of the Eclipse Public License v1.0
 *  which accompanies this distribution, and is available at
 *  http://www.eclipse.org/legal/epl-v10.html
 *
 *  Contributors:
 *      VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.databoard.parser.unparsing;

import gnu.trove.map.hash.THashMap;
import gnu.trove.procedure.TObjectObjectProcedure;
import gnu.trove.set.hash.THashSet;

import org.simantics.databoard.type.ArrayType;
import org.simantics.databoard.type.BooleanType;
import org.simantics.databoard.type.ByteType;
import org.simantics.databoard.type.Component;
import org.simantics.databoard.type.Datatype;
import org.simantics.databoard.type.Datatype.Visitor;
import org.simantics.databoard.type.DoubleType;
import org.simantics.databoard.type.FloatType;
import org.simantics.databoard.type.IntegerType;
import org.simantics.databoard.type.LongType;
import org.simantics.databoard.type.MapType;
import org.simantics.databoard.type.OptionalType;
import org.simantics.databoard.type.RecordType;
import org.simantics.databoard.type.StringType;
import org.simantics.databoard.type.UnionType;
import org.simantics.databoard.type.VariantType;


/**
 * @author Hannu Niemistö
 */
public class DataTypePrinter2 {

    StringBuilder sb;
    int indentation = 0;
    THashMap<Datatype, String> refs = new THashMap<Datatype, String>();

    private DataTypePrinter2(StringBuilder sb) {
        this.sb = sb;
    }

    void newLine() {
        sb.append('\n');
        for(int i=0;i<indentation;++i)
            sb.append("    ");
    }
    
    boolean useRef = true;
    Visitor<Object> printVisitor = new Visitor<Object>() {

        @Override
        public Object visit(ArrayType b) {
            useRef = true;
            sb.append("Array(");
            b.componentType.accept(printVisitor);
            sb.append(")");
            return null;
        }

        @Override
        public Object visit(BooleanType b) {
            useRef = true;
            sb.append("Boolean");
            return null;
        }

        @Override
        public Object visit(DoubleType b) {
            useRef = true;
            sb.append("Double");
            return null;
        }

        @Override
        public Object visit(FloatType b) {
            useRef = true;
            sb.append("Float");
            return null;
        }

        @Override
        public Object visit(IntegerType b) {
            useRef = true;
            sb.append("Integer");
            return null;
        }

        @Override
        public Object visit(ByteType b) {
            useRef = true;
            sb.append("Byte");
            return null;
        }

        @Override
        public Object visit(LongType b) {
            useRef = true;
            sb.append("Long");
            return null;
        }

        @Override
        public Object visit(OptionalType b) {
            useRef = true;
            sb.append("Optional(");
            b.componentType.accept(printVisitor);
            sb.append(")");
            return null;
        }

        @Override
        public Object visit(RecordType b) {
            if(refs.containsKey(b) && useRef)
                sb.append(refs.get(b));
            else {
                useRef = true;
                sb.append("{");
                ++indentation;
                for(int i=0;i<b.getComponentCount();++i) {
                    if(i > 0)
                        sb.append(", ");
                    Component c = b.getComponent(i);
                    newLine();
                    sb.append(c.name);
                    sb.append(" : ");
                    c.type.accept(printVisitor);
                }
                --indentation;
                newLine();
                sb.append("}");
            }
            return null;
        }

        @Override
        public Object visit(StringType b) {
            useRef = true;
            sb.append("String");
            return null;
        }

        @Override
        public Object visit(UnionType b) {
            if(refs.containsKey(b) && useRef)
                sb.append(refs.get(b));
            else {
                useRef = true;
                ++indentation;
                for(int i=0;i<b.getComponentCount();++i) {
                    newLine();
                    sb.append("| ");
                    Component c = b.getComponent(i);
                    sb.append(c.name);
                    sb.append(" ");
                    c.type.accept(printVisitor);
                }
                --indentation;
            }
            return null;
        }

        @Override
        public Object visit(VariantType b) {
            useRef = true;
            sb.append("Variant");
            return null;
        }

        @Override
        public Object visit(MapType b) {
            useRef = true;
            sb.append("Map(");
            b.keyType.accept(printVisitor);
            sb.append(", ");
            b.valueType.accept(printVisitor);
            sb.append(")");
            return null;
        }

    };

    THashSet<Datatype> seen = new THashSet<Datatype>();

    private void collectRefs(Datatype dt) {
        if(dt instanceof RecordType || dt instanceof UnionType) {
            if(!seen.add(dt)) {
                if(!refs.containsKey(dt))
                    refs.put(dt, "T" + refs.size());
                return;
            }
        }
        dt.accept(refCollectVisitor);
    }

    Visitor<Object> refCollectVisitor = new Visitor<Object>() {

        @Override
        public Object visit(ArrayType b) {
            collectRefs(b.componentType);
            return null;
        }

        @Override
        public Object visit(BooleanType b) {
            return null;
        }

        @Override
        public Object visit(DoubleType b) {
            return null;
        }

        @Override
        public Object visit(FloatType b) {
            return null;
        }

        @Override
        public Object visit(IntegerType b) {
            return null;
        }

        @Override
        public Object visit(ByteType b) {
            return null;
        }

        @Override
        public Object visit(LongType b) {
            return null;
        }

        @Override
        public Object visit(OptionalType b) {
            collectRefs(b.componentType);
            return null;
        }

        @Override
        public Object visit(RecordType b) {
            for(Component c : b.getComponents())
                collectRefs(c.type);
            return null;
        }

        @Override
        public Object visit(StringType b) {
            return null;
        }

        @Override
        public Object visit(UnionType b) {
            for(Component c : b.getComponents())
                collectRefs(c.type);
            return null;
        }

        @Override
        public Object visit(VariantType b) {
            return null;
        }

        @Override
        public Object visit(MapType b) {
            collectRefs(b.keyType);
            collectRefs(b.valueType);
            return null;
        }

    };

    void printDt(Datatype dt) {
        collectRefs(dt);
        dt.accept(printVisitor);
        if(!refs.isEmpty()) {
            newLine();
            sb.append("where");
            ++indentation;
            refs.forEachEntry(new TObjectObjectProcedure<Datatype, String>() {
                @Override
                public boolean execute(Datatype a, String b) {
                    newLine();
                    sb.append(b).append(" = ");
                    useRef = false;
                    a.accept(printVisitor);
                    return true;
                }
            });
            --indentation;
            refs.clear();
        }
    }
    
    public static String print(Datatype dt) {
        StringBuilder sb = new StringBuilder();
        new DataTypePrinter2(sb).printDt(dt);
        return sb.toString();
    }

}