package org.gcube.accounting.analytics.persistence.postgresql;

import java.util.HashMap;
import java.util.Map;
import java.util.Set;

import org.gcube.documentstore.records.AggregatedRecord;
import org.gcube.documentstore.records.Record;

public class RecordToDBMapper {
	
	protected static String getRecordTypeByClass(Class<? extends AggregatedRecord<?, ?>> clz) {
		try {
			Record r = clz.newInstance();
			return r.getRecordType();
		}catch (Exception e) {
			String type = clz.getSimpleName();
			type = type.replace("Abstract", "");
			type = type.replace("Aggregated", "");
			return type;
		}
	}
	
	protected static String getKey(String fieldName) {
		StringBuffer stringBuffer = new StringBuffer();
		int lenght = fieldName.length();
		boolean lastLowerCase = true;
        for (int i=0; i<lenght; i++) { 
           Character ch = fieldName.charAt(i); /*traversing String one by one*/
            if (Character.isUpperCase(ch)) {
            	if(lastLowerCase) {
            		stringBuffer.append("_");
            	}
            	lastLowerCase = false;
            }else {
            	lastLowerCase = true;
            }
            stringBuffer.append(Character.toLowerCase(ch));
        }
        return stringBuffer.toString();
	}
	
	protected final Class<? extends AggregatedRecord<?, ?>> clz;
	
	protected final String typeName;
	protected final String tableName;
	
	protected final Map<String, String> tableFieldToUsageRecordField;
	protected final Map<String, String> usageRecordFieldToTableField;
	
	public RecordToDBMapper(Class<? extends AggregatedRecord<?, ?>> clz) throws Exception {
		this.clz = clz;
		this.typeName = getRecordTypeByClass(clz);
		this.tableName = typeName.toLowerCase();
		this.tableFieldToUsageRecordField = new HashMap<>();
		this.usageRecordFieldToTableField = new HashMap<>();
		mapFields();
	}
	
	public RecordToDBMapper(String typeName, Class<? extends AggregatedRecord<?, ?>> clz) throws Exception {
		this.clz = clz;
		this.typeName = typeName;
		this.tableName = typeName.toLowerCase();
		this.tableFieldToUsageRecordField = new HashMap<>();
		this.usageRecordFieldToTableField = new HashMap<>();
		mapFields();
	}
	
	protected void mapFields() throws Exception {
		Set<String> requiredFields = clz.newInstance().getRequiredFields();
		for(String usageRecordField : requiredFields) {
			String dbField = getKey(usageRecordField);
			tableFieldToUsageRecordField.put(dbField, usageRecordField);
			usageRecordFieldToTableField.put(usageRecordField, dbField);
		}
	}
	
	public String getTableField(String usageRecordField) {
		return usageRecordFieldToTableField.get(usageRecordField);
	}
	
	public String getUsageRecordField(String tableField) {
		String ret = tableFieldToUsageRecordField.get(tableField);
		if(ret==null && usageRecordFieldToTableField.keySet().contains(tableField)) {
			ret = tableField;
		}
		return ret;
	}

	public String getTypeName() {
		return typeName;
	}

	public String getTableName() {
		return tableName;
	}
	
}