package org.hathitrust;

import java.io.BufferedReader;
import java.util.ArrayList;
import java.util.Iterator;

import org.apache.spark.api.java.function.FlatMapFunction;
import org.json.JSONArray;
import org.json.JSONObject;

/*
class PagedJSON implements Function<String, Boolean> {

	private static final long serialVersionUID = 1L;

	public Boolean call(String s) { return s.contains("a"); }
}
 */


class PagedJSON implements FlatMapFunction<String, String> 
{
	private static final long serialVersionUID = 1L;

	protected String _input_dir;
	protected String _output_dir;
	protected int    _verbosity;
	
	public PagedJSON(String input_dir, String output_dir, int verbosity)
	{
		_input_dir  = input_dir;
		_output_dir = output_dir;
		_verbosity  = verbosity;
	}
	
	protected JSONObject readJSONFile(String filename)
	{
		//Path path = Paths.get(filename);

		StringBuilder sb = new StringBuilder();

		try {

			String str;
			BufferedReader br = ClusterFileIO.getBufferedReaderForCompressedFile(_input_dir + "/" + filename);
			while ((str = br.readLine()) != null) {
				sb.append(str);
			}

	        br.close();
		} 
		catch (Exception e) {
			e.printStackTrace();
		}

		JSONObject json_obj = new JSONObject(sb.toString());
		
		return json_obj;
	}

	public Iterator<String> call(String json_file_in) 
	{ 
		JSONObject extracted_feature_record = readJSONFile(json_file_in);
		
		// Check output directory for volume exists, and create it if not
		
		
		String id = extracted_feature_record.getString("id");
		
		//JSONObject ef_metadata = extracted_feature_record.getJSONObject("metadata");
		JSONObject ef_features = extracted_feature_record.getJSONObject("features");
		
		
		int ef_page_count = ef_features.getInt("pageCount");
		
		if (_verbosity >= 1) {
			System.out.println("Processing: " + json_file_in);
			System.out.println("  pageCount = " + ef_page_count);
		}
		
		JSONArray ef_pages = ef_features.getJSONArray("pages");
		int ef_num_pages = ef_pages.length();
		
		// Make directory for page-level JSON output
		String json_dir = ClusterFileIO.removeSuffix(json_file_in,".json.bz2");
		String page_json_dir = json_dir + "/pages";
		//ClusterFileIO.createDirectoryAll(_output_dir + "/" + page_json_dir);
		System.out.println("mkdir: " + _output_dir + "/" + page_json_dir);
		
		ArrayList<String> ids = new ArrayList<String>(ef_num_pages);
		for (int i = 0; i < ef_page_count; i++) {
			String formatted_i = String.format("page-%06d", i);
			String page_id = id + "." + formatted_i;
		
			if (_verbosity >= 2) {
			  System.out.println("  Page: " + page_id);
			}
			
			// create JSON obj of just the page (for now)
			// write it out
			
			ids.add(page_json_dir +"/" + page_id + ".json.bz2");
			
			if (i==0) {
				System.out.println("Sample output JSON page file: " + page_json_dir +"/" + page_id + ".json.bz2");
			}
		}
		
		/*
		for (int i = 0; i < ef_num_pages; i++)
		{
		    //String post_id = ef_pages.getJSONObject(i).getString("post_id");
		    //......
		}
		*/
		//String pageName = json_obj.getJSONObject("pageInfo").getString("pageName");
/*
		JSONArray arr = obj.getJSONArray("posts");
		for (int i = 0; i < arr.length(); i++)
		{
		    String post_id = arr.getJSONObject(i).getString("post_id");
		    ......
		}
*/
		
		
		ids.add(id);
		
		return ids.iterator();
	}
}