/*

Copyright 2011, Google Inc.
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modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
    * Redistributions in binary form must reproduce the above
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in the documentation and/or other materials provided with the
distribution.
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contributors may be used to endorse or promote products derived from
this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"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,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

package com.google.refine.importing;

import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.io.Writer;
import java.util.LinkedList;
import java.util.List;
import java.util.Properties;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import org.json.JSONWriter;

import com.google.refine.RefineServlet;
import com.google.refine.commands.HttpUtilities;
import com.google.refine.importing.ImportingManager.Format;
import com.google.refine.util.JSONUtilities;
import com.google.refine.util.ParsingUtilities;

public class DefaultImportingController implements ImportingController {

    protected RefineServlet servlet;
    
    @Override
    public void init(RefineServlet servlet) {
        this.servlet = servlet;
    }

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
        // TODO Auto-generated method stub
    }

    @Override
    public void doPost(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {

        /*
         * The uploaded file is in the POST body as a "file part". If
         * we call request.getParameter() then the POST body will get
         * read and we won't have a chance to parse the body ourselves.
         * This is why we have to parse the URL for parameters ourselves.
         */
        Properties parameters = ParsingUtilities.parseUrlParameters(request);
        String subCommand = parameters.getProperty("subCommand");
        if ("load-raw-data".equals(subCommand)) {
            doLoadRawData(request, response, parameters);
        } else if ("update-file-selection".equals(subCommand)) {
            doUpdateFileSelection(request, response, parameters);
        } else if ("initialize-parser-ui".equals(subCommand)) {
            doInitializeParserUI(request, response, parameters);
        } else if ("update-format-and-options".equals(subCommand)) {
            doUpdateFormatAndOptions(request, response, parameters);
        } else if ("create-project".equals(subCommand)) {
            doCreateProject(request, response, parameters);
        } else {
            HttpUtilities.respond(response, "error", "No such sub command");
        }
    }

    private void doLoadRawData(HttpServletRequest request, HttpServletResponse response, Properties parameters)
        throws ServletException, IOException {

        long jobID = Long.parseLong(parameters.getProperty("jobID"));
        ImportingJob job = ImportingManager.getJob(jobID);
        if (job == null) {
            HttpUtilities.respond(response, "error", "No such import job");
            return;
        }
        
        job.updating = true;
        try {
            JSONObject config = job.getOrCreateDefaultConfig();
            if (!("new".equals(config.getString("state")))) {
                HttpUtilities.respond(response, "error", "Job already started; cannot load more data");
                return;
            }
            
            ImportingUtilities.loadDataAndPrepareJob(
                request, response, parameters, job, config);
        } catch (JSONException e) {
            throw new ServletException(e);
        } finally {
            job.touch();
            job.updating = false;
        }
    }
    
    private void doUpdateFileSelection(HttpServletRequest request, HttpServletResponse response, Properties parameters)
        throws ServletException, IOException {
    
        long jobID = Long.parseLong(parameters.getProperty("jobID"));
        ImportingJob job = ImportingManager.getJob(jobID);
        if (job == null) {
            HttpUtilities.respond(response, "error", "No such import job");
            return;
        }
        
        job.updating = true;
        try {
            JSONObject config = job.getOrCreateDefaultConfig();
            if (!("ready".equals(config.getString("state")))) {
                HttpUtilities.respond(response, "error", "Job not ready");
                return;
            }
            
            JSONArray fileSelectionArray = ParsingUtilities.evaluateJsonStringToArray(
                    request.getParameter("fileSelection"));
            
            ImportingUtilities.updateJobWithNewFileSelection(job, fileSelectionArray);
            
            replyWithJobData(request, response, job);
        } catch (JSONException e) {
            throw new ServletException(e);
        } finally {
            job.touch();
            job.updating = false;
        }
    }
    
    private void doUpdateFormatAndOptions(HttpServletRequest request, HttpServletResponse response, Properties parameters)
        throws ServletException, IOException {
    
        long jobID = Long.parseLong(parameters.getProperty("jobID"));
        ImportingJob job = ImportingManager.getJob(jobID);
        if (job == null) {
            HttpUtilities.respond(response, "error", "No such import job");
            return;
        }
        
        job.updating = true;
        try {
            JSONObject config = job.getOrCreateDefaultConfig();
            if (!("ready".equals(config.getString("state")))) {
                HttpUtilities.respond(response, "error", "Job not ready");
                return;
            }
            
            String format = request.getParameter("format");
            JSONObject optionObj = ParsingUtilities.evaluateJsonStringToObject(
                    request.getParameter("options"));
            
            List<Exception> exceptions = new LinkedList<Exception>();
            
            ImportingUtilities.previewParse(job, format, optionObj, exceptions);
            
            Writer w = response.getWriter();
            JSONWriter writer = new JSONWriter(w);
            try {
                writer.object();
                if (exceptions.size() == 0) {
                    job.project.update(); // update all internal models, indexes, caches, etc.
                    
                    writer.key("status"); writer.value("ok");
                } else {
                    writer.key("status"); writer.value("error");
                    writer.key("errors");
                    writer.array();
                    writeErrors(writer, exceptions);
                    writer.endArray();
                }
                writer.endObject();
            } catch (JSONException e) {
                throw new ServletException(e);
            } finally {
                w.flush();
                w.close();
            }
        } catch (JSONException e) {
            throw new ServletException(e);
        } finally {
            job.touch();
            job.updating = false;
        }
    }
    
    private void doInitializeParserUI(HttpServletRequest request, HttpServletResponse response, Properties parameters)
        throws ServletException, IOException {
    
        long jobID = Long.parseLong(parameters.getProperty("jobID"));
        ImportingJob job = ImportingManager.getJob(jobID);
        if (job == null) {
            HttpUtilities.respond(response, "error", "No such import job");
            return;
        }
        
        String format = request.getParameter("format");
        Format formatRecord = ImportingManager.formatToRecord.get(format);
        if (formatRecord != null && formatRecord.parser != null) {
            JSONObject options = formatRecord.parser.createParserUIInitializationData(
                    job, ImportingUtilities.getSelectedFileRecords(job), format);
            JSONObject result = new JSONObject();
            JSONUtilities.safePut(result, "status", "ok");
            JSONUtilities.safePut(result, "options", options);
            
            HttpUtilities.respond(response, result.toString());
        } else {
            HttpUtilities.respond(response, "error", "Unrecognized format or format has no parser");
        }
    }
    
    private void doCreateProject(HttpServletRequest request, HttpServletResponse response, Properties parameters)
        throws ServletException, IOException {
    
        long jobID = Long.parseLong(parameters.getProperty("jobID"));
        ImportingJob job = ImportingManager.getJob(jobID);
        if (job == null) {
            HttpUtilities.respond(response, "error", "No such import job");
            return;
        }
        
        job.updating = true;
        job.touch();
        try {
            JSONObject config = job.getOrCreateDefaultConfig();
            if (!("ready".equals(config.getString("state")))) {
                HttpUtilities.respond(response, "error", "Job not ready");
                return;
            }
            
            String format = request.getParameter("format");
            JSONObject optionObj = ParsingUtilities.evaluateJsonStringToObject(
                    request.getParameter("options"));
            
            List<Exception> exceptions = new LinkedList<Exception>();
            
            ImportingUtilities.createProject(job, format, optionObj, exceptions, false);
            
            HttpUtilities.respond(response, "ok", "done");
        } catch (JSONException e) {
            throw new ServletException(e);
        }
    }

    private void replyWithJobData(HttpServletRequest request, HttpServletResponse response, ImportingJob job)
        throws ServletException, IOException {
        
        Writer w = response.getWriter();
        JSONWriter writer = new JSONWriter(w);
        try {
            writer.object();
            writer.key("code"); writer.value("ok");
            writer.key("job"); job.write(writer, new Properties());
            writer.endObject();
        } catch (JSONException e) {
            throw new ServletException(e);
        } finally {
            w.flush();
            w.close();
        }
    }
    
    static public void writeErrors(JSONWriter writer, List<Exception> exceptions) throws JSONException {
        for (Exception e : exceptions) {
            StringWriter sw = new StringWriter();
            e.printStackTrace(new PrintWriter(sw));
            
            writer.object();
            writer.key("message");
            writer.value(e.getLocalizedMessage());
            writer.key("stack");
            writer.value(sw.toString());
            writer.endObject();
        }
    }
    
    static public JSONArray convertErrorsToJsonArray(List<Exception> exceptions) {
        JSONArray a = new JSONArray();
        for (Exception e : exceptions) {
            StringWriter sw = new StringWriter();
            e.printStackTrace(new PrintWriter(sw));
            
            JSONObject o = new JSONObject();
            JSONUtilities.safePut(o, "message", e.getLocalizedMessage());
            JSONUtilities.safePut(o, "stack", sw.toString());
            JSONUtilities.append(a, o);
        }
        return a;
    }

}