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Copyright 2010, Google Inc.
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    * Redistributions of source code must retain the above copyright
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    * Redistributions in binary form must reproduce the above
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contributors may be used to endorse or promote products derived from
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,           
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY           
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*/

package com.google.refine.templating;

import java.io.IOException;
import java.io.Writer;
import java.util.Collection;
import java.util.List;
import java.util.Properties;

import com.google.refine.browsing.RecordVisitor;
import com.google.refine.browsing.RowVisitor;
import com.google.refine.expr.ExpressionUtils;
import com.google.refine.model.Project;
import com.google.refine.model.Record;
import com.google.refine.model.Row;

public class Template {
    protected String _prefix;
    protected String _suffix;
    protected String _separator;

    protected List<Fragment> _fragments;

    public Template(List<Fragment> fragments) {
        _fragments = fragments;
    }

    public void setPrefix(String prefix) {
        _prefix = prefix;
    }

    public void setSuffix(String suffix) {
        _suffix = suffix;
    }

    public void setSeparator(String separator) {
        _separator = separator;
    }

    public RowVisitor getRowVisitor(Writer writer, int limit) {
        return get(writer, limit);
    }

    public RecordVisitor getRecordVisitor(Writer writer, int limit) {
        return get(writer, limit);
    }

    protected RowWritingVisitor get(Writer writer, int limit) {
        return new RowWritingVisitor(writer, limit);
    }

    protected class RowWritingVisitor implements RowVisitor, RecordVisitor {
        final protected int limit;
        final protected Writer writer;
        protected Properties bindings;

        public int total;

        public RowWritingVisitor(Writer writer, int limit) {
            this.limit = limit;
            this.writer = writer;
        }

        @Override
        public void start(Project project) {
            bindings = ExpressionUtils.createBindings(project);

            try {
                if (_prefix != null) {
                    writer.write(_prefix);
                }
            } catch (IOException e) {
                // ignore
            }
        }

        @Override
        public void end(Project project) {
            try {
                if (_suffix != null) {
                    writer.write(_suffix);
                }
            } catch (IOException e) {
                // ignore
            }
        }

        @Override
        public boolean visit(Project project, int rowIndex, Row row) {
            if (limit <= 0 || total < limit) {
                internalVisit(project, rowIndex, row);
            }
            total++;

            return limit > 0 && total >= limit;
        }

        @Override
        public boolean visit(Project project, Record record) {
            if (limit <= 0 || total < limit) {
                internalVisit(project, record);
            }
            total++;

            return limit > 0 && total >= limit;
        }

        protected void writeValue(Object v) throws IOException {
            if (v == null) {
                writer.write("null");
            } else if (ExpressionUtils.isError(v)) {
                writer.write("null");
                //writer.write("[Error: " + ((EvalError) v).message);
            } else if (v instanceof String) {
                writer.write((String) v);
            } else {
                writer.write(v.toString());
            }
        }

        public boolean internalVisit(Project project, int rowIndex, Row row) {
            try {
                if (total > 0 && _separator != null) {
                    writer.write(_separator);
                }

                ExpressionUtils.bind(bindings, row, rowIndex, null, null);
                for (Fragment f : _fragments) {
                    if (f instanceof StaticFragment) {
                        writer.write(((StaticFragment) f).text);
                    } else {
                        DynamicFragment df = (DynamicFragment) f;
                        Object value = df.eval.evaluate(bindings);

                        if (value != null && ExpressionUtils.isArrayOrCollection(value)) {
                            if (ExpressionUtils.isArray(value)) {
                                Object[] a = (Object[]) value;
                                for (Object v : a) {
                                    writeValue(v);
                                }
                            } else {
                                Collection<Object> a = ExpressionUtils.toObjectCollection(value);
                                for (Object v : a) {
                                    writeValue(v);
                                }
                            }
                            continue;
                        }

                        writeValue(value);
                    }
                }
            } catch (IOException e) {
                // ignore
            }
            return false;
        }

        protected boolean internalVisit(Project project, Record record) {
            bindings.put("recordIndex", record.recordIndex);

            for (int r = record.fromRowIndex; r < record.toRowIndex; r++) {
                Row row = project.rows.get(r);

                bindings.put("rowIndex", r);

                internalVisit(project, r, row);

                bindings.remove("recordIndex");
            }
            return false;
        }
    }

}
