/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.sparql.sse.writers;

import java.io.OutputStream ;
import java.util.Iterator ;
import java.util.List ;

import org.apache.jena.atlas.io.IndentedWriter ;
import org.apache.jena.graph.Triple ;
import org.apache.jena.query.Query ;
import org.apache.jena.query.SortCondition ;
import org.apache.jena.shared.PrefixMapping ;
import org.apache.jena.sparql.ARQConstants ;
import org.apache.jena.sparql.algebra.Op ;
import org.apache.jena.sparql.algebra.OpPrefixesUsed ;
import org.apache.jena.sparql.algebra.OpVisitor ;
import org.apache.jena.sparql.algebra.op.* ;
import org.apache.jena.sparql.algebra.table.TableEmpty;
import org.apache.jena.sparql.algebra.table.TableUnit ;
import org.apache.jena.sparql.core.* ;
import org.apache.jena.sparql.expr.Expr ;
import org.apache.jena.sparql.expr.ExprAggregator ;
import org.apache.jena.sparql.expr.ExprList ;
import org.apache.jena.sparql.pfunction.PropFuncArg ;
import org.apache.jena.sparql.serializer.SerializationContext ;
import org.apache.jena.sparql.sse.Tags ;
import org.apache.jena.sparql.util.FmtUtils ;

// ToDo extract write of:
// Table
// Triple and quads

public class WriterOp
{
    private static final int NL     = WriterLib.NL ;
    private static final int NoNL   = WriterLib.NoNL ;    // No newline, with space
    private static final int NoSP   = WriterLib.NoSP ;

    public static void output(Op op)
    { output(System.out, op) ; }

    public static void output(Op op, PrefixMapping pMap)
    { output(System.out, op, pMap) ; }

    public static void output(Op op, Prologue prologue)
    { output(System.out, op, prologue) ; }

    public static void output(OutputStream out, Op op)
    { output(out, op, (PrefixMapping)null) ; }

    public static void output(OutputStream out, Op op, PrefixMapping pMap)
    { output(new IndentedWriter(out), op, pMap) ; }

    public static void output(OutputStream out, Op op, Prologue prologue)
    { output(new IndentedWriter(out), op, prologue) ; }

    public static void output(IndentedWriter iWriter, Op op)
    { output(iWriter, op, (PrefixMapping)null) ; }

    public static void output(IndentedWriter iWriter, Op op, PrefixMapping pMap) {
        if ( pMap == null )
            pMap = OpPrefixesUsed.used(op, ARQConstants.getGlobalPrefixMap()) ;
        SerializationContext sCxt = new SerializationContext(pMap) ;
        output(iWriter, op, sCxt) ;
    }

    public static void output(IndentedWriter iWriter, Op op, Prologue prologue) {
        SerializationContext sCxt = new SerializationContext(prologue) ;
        output(iWriter, op, sCxt) ;
    }

    public static void output(OutputStream out, Op op, SerializationContext sCxt) {
        output(new IndentedWriter(out), op, sCxt) ;
    }

    // Actual work
    public static void output(final IndentedWriter iWriter, final Op op, SerializationContext sCxt) {
        if ( sCxt == null )
            sCxt = new SerializationContext() ;
        final SerializationContext sCxt2 = sCxt ;
        WriterBasePrefix.Fmt fmt = new WriterBasePrefix.Fmt() {
            @Override
            public void format() {
                op.visit(new OpWriterWorker(iWriter, sCxt2)) ;
            }
        } ;
        WriterBasePrefix.output(iWriter, fmt, sCxt2.getPrologue()) ;
    }

    // Without the base/prefix wrapper.
    static void outputNoPrologue(final IndentedWriter iWriter, final Op op, final SerializationContext sCxt) {
        OpWriterWorker v = new OpWriterWorker(iWriter, sCxt) ;
        op.visit(v) ;
    }

    public static class OpWriterWorker implements OpVisitor {
        private IndentedWriter       out ;
        private SerializationContext sContext ;

        public OpWriterWorker(IndentedWriter out, SerializationContext sCxt) {
            this.sContext = sCxt ;
            this.out = out ;
        }

        private void visitOpN(OpN op) {
            start(op, NL) ;
            for ( Iterator<Op> iter = op.iterator() ; iter.hasNext() ; ) {
                Op sub = iter.next() ;
                out.ensureStartOfLine() ;
                printOp(sub) ;
            }
            finish(op) ;
        }

        private void visitOp2(Op2 op, ExprList exprs) {
            start(op, NL) ;
            printOp(op.getLeft()) ;

            out.ensureStartOfLine() ;

            printOp(op.getRight()) ;
            if ( exprs != null ) {
                out.ensureStartOfLine() ;
                WriterExpr.output(out, exprs, sContext) ;
            }
            finish(op) ;
        }

        private void visitOp1(Op1 op) {
            start(op, NL) ;
            printOp(op.getSubOp()) ;
            finish(op) ;
        }

        @Override
        public void visit(OpBGP opBGP) {
            if ( opBGP.getPattern().size() == 1 ) {
                start(opBGP, NoNL) ;
                write(opBGP.getPattern(), true) ;
                finish(opBGP) ;
                return ;
            }

            start(opBGP, NL) ;
            write(opBGP.getPattern(), false) ;
            finish(opBGP) ;
        }

        @Override
        public void visit(OpQuadPattern opQuadP) {
            QuadPattern quads = opQuadP.getPattern() ;
            if ( quads.size() == 1 ) {
                start(opQuadP, NoNL) ;
                formatQuad(quads.get(0)) ;
                finish(opQuadP) ;
                return ;
            }
            start(opQuadP, NL) ;
            write(quads, false) ;
            finish(opQuadP) ;
        }

        @Override
        public void visit(OpQuadBlock opQuads) {
            QuadPattern quads = opQuads.getPattern() ;
            if ( quads.size() == 1 ) {
                start(opQuads, NoNL) ;
                formatQuad(quads.get(0)) ;
                finish(opQuads) ;
                return ;
            }
            start(opQuads, NL) ;
            write(quads, false) ;
            finish(opQuads) ;
        }

        private void write(BasicPattern pattern, boolean oneLine) {
            boolean first = true ;
            for ( Triple t : pattern ) {
                formatTriple(t) ;
                if ( oneLine ) {
                    if ( !first )
                        out.print(" ") ;
                } else
                    out.println() ;
                first = false ;
            }
        }

        private void write(QuadPattern quads, boolean oneLine) {
            boolean first = true ;
            for ( Quad t : quads ) {
                formatQuad(t) ;
                if ( oneLine ) {
                    if ( !first )
                        out.print(" ") ;
                } else
                    out.println() ;
                first = false ;
            }
        }

        @Override
        public void visit(OpTriple opTriple) {
            formatTriple(opTriple.getTriple()) ;
        }

        @Override
        public void visit(OpQuad opQuad) {
            formatQuad(opQuad.getQuad()) ;
        }

        @Override
        public void visit(OpPath opPath) {
            // start(opPath, NoNL) ;
            formatTriplePath(opPath.getTriplePath()) ;
            // finish(opPath) ;
        }

        @Override
        public void visit(OpProcedure opProc) {
            start(opProc, NoNL) ;
            WriterNode.output(out, opProc.getProcId(), sContext) ;
            out.println() ;
            WriterExpr.output(out, opProc.getArgs(), true, false, sContext) ;
            out.println() ;
            printOp(opProc.getSubOp()) ;
            finish(opProc) ;
        }

        @Override
        public void visit(OpPropFunc opPropFunc) {
            start(opPropFunc, NoNL) ;
            out.print(FmtUtils.stringForNode(opPropFunc.getProperty(), sContext)) ;
            out.println() ;

            outputPF(opPropFunc.getSubjectArgs()) ;
            out.print(" ") ;
            outputPF(opPropFunc.getObjectArgs()) ;
            out.println() ;
            printOp(opPropFunc.getSubOp()) ;
            finish(opPropFunc) ;
        }

        private void outputPF(PropFuncArg pfArg) {
            if ( pfArg.isNode() ) {
                WriterNode.output(out, pfArg.getArg(), sContext) ;
                return ;
            }
            WriterNode.output(out, pfArg.getArgList(), sContext) ;
        }

        @Override
        public void visit(OpJoin opJoin) {
            visitOp2(opJoin, null) ;
        }

        @Override
        public void visit(OpSequence opSequence) {
            visitOpN(opSequence) ;
        }

        @Override
        public void visit(OpDisjunction opDisjunction) {
            visitOpN(opDisjunction) ;
        }

        @Override
        public void visit(OpLeftJoin opLeftJoin) {
            visitOp2(opLeftJoin, opLeftJoin.getExprs()) ;
        }

        @Override
        public void visit(OpDiff opDiff) {
            visitOp2(opDiff, null) ;
        }

        @Override
        public void visit(OpMinus opMinus) {
            visitOp2(opMinus, null) ;
        }

        @Override
        public void visit(OpUnion opUnion) {
            visitOp2(opUnion, null) ;
        }

        @Override
        public void visit(OpConditional opCondition) {
            visitOp2(opCondition, null) ;
        }

        @Override
        public void visit(OpFilter opFilter) {
            start(opFilter, NoNL) ;

            ExprList exprs = opFilter.getExprs() ;
            if ( exprs == null ) {
                start() ;
                finish() ;
            } else
                WriterExpr.output(out, exprs, sContext) ;
            out.println() ;
            printOp(opFilter.getSubOp()) ;

            finish(opFilter) ;
        }

        @Override
        public void visit(OpGraph opGraph) {
            start(opGraph, NoNL) ;
            out.println(FmtUtils.stringForNode(opGraph.getNode(), sContext)) ;
            opGraph.getSubOp().visit(this) ;
            finish(opGraph) ;
        }

        @Override
        public void visit(OpService opService) {
            start(opService, NoNL) ;
            if ( opService.getSilent() )
                out.println("silent ") ;
            out.println(FmtUtils.stringForNode(opService.getService(), sContext)) ;
            opService.getSubOp().visit(this) ;
            finish(opService) ;
        }

        @Override
        public void visit(OpTable opTable) {
            if ( TableUnit.isTableUnit(opTable.getTable()) ) {
                start(opTable, NoNL) ;
                out.print("unit") ;
                finish(opTable) ;
                return ;
            }

            if ( TableEmpty.isTableEmpty(opTable.getTable()) ) {
                start(opTable, NoNL) ;
                out.print("empty") ;
                finish(opTable) ;
                return ;
            }

            start(opTable, NoNL) ;
            WriterNode.outputVars(out, opTable.getTable().getVars(), sContext) ;
            if ( ! opTable.getTable().isEmpty() ) {
                out.println();
                WriterTable.outputPlain(out, opTable.getTable(), sContext) ;
            }
            finish(opTable) ;
        }

        @Override
        public void visit(OpDatasetNames dsNames) {
            start(dsNames, NoNL) ;
            WriterNode.output(out, dsNames.getGraphNode(), sContext) ;
            finish(dsNames) ;
        }

        @Override
        public void visit(OpExt opExt) {
            // start(opExt, NL) ;
            opExt.output(out, sContext) ;
            // finish(opExt) ;
        }

        @Override
        public void visit(OpNull opNull) {
            start(opNull, NoSP) ;
            finish(opNull) ;
        }

        @Override
        public void visit(OpLabel opLabel) {
            String x = FmtUtils.stringForString(opLabel.getObject().toString()) ;
            if ( opLabel.hasSubOp() ) {
                start(opLabel, NL) ;
                out.println(x) ;
                printOp(opLabel.getSubOp()) ;
                finish(opLabel) ;
            } else {
                start(opLabel, NoNL) ;
                out.print(x) ;
                finish(opLabel) ;
            }
        }

        @Override
        public void visit(OpList opList) {
            visitOp1(opList) ;
        }

        @Override
        public void visit(OpGroup opGroup) {
            start(opGroup, NoNL) ;
            writeNamedExprList(opGroup.getGroupVars()) ;
            if ( !opGroup.getAggregators().isEmpty() ) {
                // --- Aggregators
                out.print(" ") ;
                start() ;
                out.incIndent() ;
                boolean first = true ;
                for ( ExprAggregator agg : opGroup.getAggregators() ) {
                    if ( !first ) {
                        out.print(" ") ;
                    }
                    first = false ;
                    Var v = agg.getVar() ;
                    String str = agg.getAggregator().toPrefixString() ;
                    start() ;
                    out.print(v.toString()) ;
                    out.print(" ") ;
                    out.print(str) ;
                    finish() ;
                }
                finish() ;
                out.decIndent() ;
            }
            out.println() ;
            printOp(opGroup.getSubOp()) ;
            finish(opGroup) ;
        }

        @Override
        public void visit(OpOrder opOrder) {
            start(opOrder, NoNL) ;

            // Write conditions
            start() ;

            boolean first = true ;
            for ( SortCondition sc : opOrder.getConditions() ) {
                if ( !first )
                    out.print(" ") ;
                first = false ;
                formatSortCondition(sc) ;
            }
            finish() ;
            out.newline() ;
            printOp(opOrder.getSubOp()) ;
            finish(opOrder) ;
        }

        @Override
        public void visit(OpTopN opTop) {
            start(opTop, NoNL) ;

            // Write conditions
            start() ;
            writeIntOrDefault(opTop.getLimit()) ;
            out.print(" ") ;

            boolean first = true ;
            for ( SortCondition sc : opTop.getConditions() ) {
                if ( !first )
                    out.print(" ") ;
                first = false ;
                formatSortCondition(sc) ;
            }
            finish() ;
            out.newline() ;
            printOp(opTop.getSubOp()) ;
            finish(opTop) ;
        }

        // Neater would be a pair of explicit SortCondition formatters
        private void formatSortCondition(SortCondition sc) {
            boolean close = true ;
            String tag = null ;

            if ( sc.getDirection() != Query.ORDER_DEFAULT ) {
                if ( sc.getDirection() == Query.ORDER_ASCENDING ) {
                    tag = Tags.tagAsc ;
                    WriterLib.start(out, tag, NoNL) ;
                }

                if ( sc.getDirection() == Query.ORDER_DESCENDING ) {
                    tag = Tags.tagDesc ;
                    WriterLib.start(out, tag, NoNL) ;
                }

            }

            WriterExpr.output(out, sc.getExpression(), sContext) ;

            if ( tag != null )
                WriterLib.finish(out, tag) ;
        }

        @Override
        public void visit(OpProject opProject) {
            start(opProject, NoNL) ;
            writeVarList(opProject.getVars()) ;
            out.println() ;
            printOp(opProject.getSubOp()) ;
            finish(opProject) ;
        }

        @Override
        public void visit(OpDistinct opDistinct) {
            visitOp1(opDistinct) ;
        }

        @Override
        public void visit(OpReduced opReduced) {
            visitOp1(opReduced) ;
        }

        @Override
        public void visit(OpAssign opAssign) {
            start(opAssign, NoNL) ;
            writeNamedExprList(opAssign.getVarExprList()) ;
            out.println() ;
            printOp(opAssign.getSubOp()) ;
            finish(opAssign) ;
        }

        @Override
        public void visit(OpExtend opExtend) {
            start(opExtend, NoNL) ;
            writeNamedExprList(opExtend.getVarExprList()) ;
            out.println() ;
            printOp(opExtend.getSubOp()) ;
            finish(opExtend) ;
        }

        @Override
        public void visit(OpSlice opSlice) {
            start(opSlice, NoNL) ;
            writeIntOrDefault(opSlice.getStart()) ;
            out.print(" ") ;
            writeIntOrDefault(opSlice.getLength()) ;
            out.println() ;
            printOp(opSlice.getSubOp()) ;
            finish(opSlice) ;
        }

        private void writeIntOrDefault(long value) {
            String x = "_" ;
            if ( value != Query.NOLIMIT )
                x = Long.toString(value) ;
            out.print(x) ;
        }

        private void start(Op op, int newline) {
            WriterLib.start(out, op.getName(), newline) ;
        }

        private void finish(Op op) {
            WriterLib.finish(out, op.getName()) ;
        }

        private void start() {
            WriterLib.start(out) ;
        }

        private void finish() {
            WriterLib.finish(out) ;
        }

        private void printOp(Op op) {
            if ( op == null ) {
                WriterLib.start(out, Tags.tagNull, NoSP) ;
                WriterLib.finish(out, Tags.tagNull) ;
            } else
                op.visit(this) ;
        }

        private void writeVarList(List<Var> vars) {
            start() ;
            boolean first = true ;
            for ( Var var : vars ) {
                if ( !first )
                    out.print(" ") ;
                first = false ;
                out.print(var.toString()) ;
            }
            finish() ;
        }

        private void writeNamedExprList(VarExprList project) {
            start() ;
            boolean first = true ;
            for ( Var v : project.getVars() ) {
                if ( !first )
                    out.print(" ") ;
                first = false ;
                Expr expr = project.getExpr(v) ;
                if ( expr != null ) {
                    start() ;
                    out.print(v.toString()) ;
                    out.print(" ") ;
                    WriterExpr.output(out, expr, sContext) ;
                    finish() ;
                } else
                    out.print(v.toString()) ;
            }
            finish() ;
        }

        private void formatTriple(Triple tp) {
            WriterNode.output(out, tp, sContext) ;
        }

        private void formatQuad(Quad qp) {
            WriterNode.output(out, qp, sContext) ;
        }

        private void formatTriplePath(TriplePath tp) {
            WriterPath.output(out, tp, sContext) ;
        }
    }
}
