/**
 * 
 */
package com.galois.fiveui;



import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.lang.reflect.Type;
import java.util.List;

import org.apache.log4j.Logger;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableList.Builder;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonIOException;
import com.google.gson.JsonObject;
import com.google.gson.JsonParseException;
import com.google.gson.JsonSyntaxException;

/**
 * @author bjones
 *
 */
public class HeadlessRunDescription {

	private static Logger logger = Logger.getLogger("com.galois.fiveui.HeadlessRunDescription");
	private static String _crawlType;
	private List<HeadlessAtom> _atoms;
    private static String _firefoxProfile;
	
	public HeadlessRunDescription (List<HeadlessAtom> atoms) {
		_atoms = atoms;
	}
	
	public List<HeadlessAtom> getAtoms() {
		return _atoms;
	}
	
	public int size() {
		return _atoms.size();
	}
	
    /**
     * Parse a JSON file into a HeadlessRunDescription
     * 
     * @param runDescFileName The file to load.
     * @return A populated HeadlessRunDescription object.
     * @throws FileNotFoundException if runDescFile can't be found.
     */
    public static HeadlessRunDescription parse(String runDescFileName) 
            throws FileNotFoundException {
        HeadlessRunDescription runDescr = null;
        try {
            GsonBuilder gsonBuilder = new GsonBuilder();
            gsonBuilder.registerTypeAdapter(HeadlessRunDescription.class, 
                    new HeadlessRunDescription.Deserializer(runDescFileName));
            Gson gson = gsonBuilder.create();
            Reader in = new InputStreamReader(new FileInputStream(runDescFileName));
            runDescr = gson.fromJson(in, HeadlessRunDescription.class);
        } catch (JsonSyntaxException e) {
            System.err.println("We were unable to parse the run description at: "+runDescFileName);
            System.err.println(e.getLocalizedMessage());

            e.printStackTrace();
            throw new IllegalStateException("Could not parse run description");
        } catch (JsonIOException e) {
            System.err.println("We were unable to load the run description at: "+runDescFileName);
            System.err.println(e.getLocalizedMessage());
            
            e.printStackTrace();
            throw new IllegalStateException("Could not parse run description");
        }
        return runDescr;
    }

    public static class Deserializer implements JsonDeserializer<HeadlessRunDescription> {
    	
    	private String _fn; // stores the filename on disk being parsed
    	private String _ctxDir; // stores the parent dir of _fn
    	
        public Deserializer(String fn) {
        	_fn = fn;
        	_ctxDir = new File(_fn).getParent();
            if (null == _ctxDir) {
                 _ctxDir = ".";
             }
        }
        
        public static void reportError(JsonElement json) {
        	logger.error("HeadlessRunDescription.parse: ran into unexpected jsonElement type: \""+json+"\"");
        	logger.error("                              " + json.getAsString());
        }
        
        /**
         * Gracefully lookup property 'prop' in JsonObject 'obj'.
         * 
         * @param obj a JSON object
         * @param prop a key string to lookup in the JSON object
         * @return string property or null if the prop doesn't resolve
         */
        public static String objGetString(JsonObject obj, String prop) {
        	JsonElement value = obj.get(prop);
        	if (null == value) {
        		logger.warn("HeadlessRunDescription.parse: failed to lookup JSON property: " + prop);
        	}
        	return null == value ? null : value.getAsString();
        }
        
        public HeadlessRunDescription deserialize(JsonElement json, Type typeOfT,
                JsonDeserializationContext context) throws JsonParseException {
        	
        	String ruleSetDir;
        	JsonArray arr;
        	
        	if (json.isJsonObject()) { // check if the description is an extended one
        		JsonObject obj = json.getAsJsonObject();
        		ruleSetDir = objGetString(obj, "rulePath");
        		String runDescDir = new File(_fn).getParent();
        		if (null != runDescDir) {
        			ruleSetDir = runDescDir + File.separator + ruleSetDir;
        		}
        		
        	    String ffProfile = objGetString(obj, "firefoxProfile");
        		if (null != ffProfile) {
        			ffProfile = runDescDir + File.separator + ffProfile;
        		}
        		_firefoxProfile = ffProfile;
        	    
        		_crawlType = objGetString(obj, "crawlType");
        		arr = obj.get("runs").getAsJsonArray();
        	} else if (json.isJsonArray()) { // description has only a list of URL/rule pairs
        		ruleSetDir = _ctxDir;
        		_crawlType = "none";
        		_firefoxProfile = null; // indicates that webdriver setup code should make a blank temp profile
        		arr = json.getAsJsonArray();
        	} else {
        		reportError(json);
        		return new HeadlessRunDescription(null);
        	}
            
            Builder<HeadlessAtom> atoms = ImmutableList.builder();
            for (JsonElement jsonElement : arr) {
                // we only care about json objects, so if anything else is found,
                // skip this loop:
                if (!jsonElement.isJsonObject()) {
                    continue;
                }
                try {
                    
                	JsonObject obj = jsonElement.getAsJsonObject();
                	atoms.add(HeadlessAtom.fromJsonObject(obj, ruleSetDir));
                } catch (IOException e) {
                	logger.error("HeadlessAtom.parse: error parsing ruleSet file: " + e.getMessage());
                	System.exit(1);
                } catch (IllegalStateException e) {
                    e.printStackTrace();
                	reportError(jsonElement);
                }
            }
            
            return new HeadlessRunDescription(atoms.build());
        }
    }
    
    public String getCrawlType() {
    	return _crawlType;
    }
    
    public String toString() {
        Gson gson = new Gson();
        return gson.toJson(this);
    }
    
    public String getFirefoxProfile() {
        return _firefoxProfile;
    }
    
    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        for (HeadlessAtom a: _atoms) {
	        result = prime * result + a.hashCode();
        }
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        HeadlessRunDescription other = (HeadlessRunDescription) obj;
        if (_atoms == null) {
            if (other._atoms != null)
                return false;
        } else if (!_atoms.equals(other._atoms))
            return false;
        
        return true;
    }

}