ProfileModel.java

package com.vorsk.crossfitr.models;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import java.math.BigDecimal;

/**
 * DAO for "profile" table.
 * 
 * Create a new instance and use the methods to interact with the database. Data
 * is returned as instances of ProfileRow where each column is a publicly
 * accessible property.
 * 
 * @author Vivek
 * @since 1.0
 */
public class ProfileModel extends SQLiteDAO {
	// // Constants

	// Table-specific columns
	public static final String COL_ATTR = "attribute";
	public static final String COL_VALUE = "value";

	/***** Constructors *****/

	/**
	 * Init SQLiteDAO with table "profile"
	 * 
	 * @param ctx
	 *            In the example they passed "this" from the calling class.. I'm
	 *            not really sure what this is yet.
	 */
	public ProfileModel(Context ctx) {
		super("profile", ctx);
	}

	/***** Private *****/

	/**
	 * Utility method to grab all the rows from a cursor
	 * 
	 * @param cr
	 *            result of a query
	 * @return Array of entries
	 */
	private ProfileRow[] fetchProfileRows(Cursor cr)
	{
		if (cr == null) {
			return null;
		}
		ProfileRow[] result = new ProfileRow[cr.getCount()];
		if (result.length == 0) {
			cr.close();
			return result;
		}

		boolean valid = cr.moveToFirst();
		int ii = 0;

		// Grab the cursor's column indices
		// An error here indicates the COL constants aren't synced with the DB
		int ind_id = cr.getColumnIndexOrThrow(COL_ID);
		int ind_attr = cr.getColumnIndexOrThrow(COL_ATTR);
		int ind_val = cr.getColumnIndexOrThrow(COL_VALUE);

		// Iterate over every row (move the cursor down the set)
		while (valid) {
			result[ii] = new ProfileRow();
			result[ii]._id = cr.getLong(ind_id);
			result[ii].attribute = cr.getString(ind_attr);
			result[ii].value = cr.getString(ind_val);

			valid = cr.moveToNext();
			ii++;
		}

		cr.close();
		return result;
	}

	/***** Public *****/

	/**
	 * Inserts a new entry into the workout table
	 * 
	 * @param row
	 *            Add this entry to the DB
	 * @return ID of newly added entry, -1 on failure
	 */
	public long insert(ProfileRow row) {
		return super.insert(row.toContentValues());
	}

	/**
	 * Inserts a new entry into the profile table, defaults record to 0
	 * 
	 * @param attr
	 *            Attribute name
	 * @param value
	 *            Value of the attribute
	 * @return ID of newly added entry, -1 on failure
	 */
	public long insert(String attr, String value) {
		ContentValues cv = new ContentValues();
		cv.put(COL_ATTR, attr);
		cv.put(COL_VALUE, value);
		return super.insert(cv);
	}

	/**
	 * Attempts to update a previously entered attribute. If the update fails,
	 * it inserts a new entry into the profile table, defaults record to 0
	 * 
	 * @param attr
	 *            Attribute name
	 * @param value
	 *            Value of the attribute
	 * @return ID of newly added entry, -1 on failure
	 */
	public long updateInsert(String attr, String value) {
		long correct = 1;
		ContentValues cv = new ContentValues();
		cv.put(COL_VALUE, value);

		correct = super.update(cv, "attribute='" + attr + "'");
		if (correct <= 0) // If update fails, insert
			return this.insert(attr, value);
		else
			return correct;
	}

	/**
	 * Fetch an entry via the ID
	 * 
	 * @param id
	 * @return Associated entry or NULL on failure
	 */
	public ProfileRow getByID(long id) {
		Cursor cr = selectByID(id);

		// ID should never return more than 1 row...
		if (cr.getCount() > 1) {
			return null; // TODO: Throw exception
		}

		ProfileRow[] rows = fetchProfileRows(cr);
		return (rows.length == 0) ? null : rows[0];
	}

	/**
	 * Fetch a specific profile attribute
	 * 
	 * @param name
	 *            Attribute name to retrieve
	 * @return Associated entry or NULL on failure
	 */
	public ProfileRow getByAttribute(String attr) {
		Cursor cr = select(new String[] { COL_ATTR }, new String[] { attr });

		// Name should be unique
		/*
		 * if (cr.getCount() > 1) { // TODO: Throw exception? }
		 */

		ProfileRow[] rows = fetchProfileRows(cr);
		return (rows.length == 0) ? null : rows[0];
	}

	/**
	 * Fetch all profile information
	 * 
	 * @return List of each profile attribute and value
	 */
	public ProfileRow[] getAll() {
		Cursor cr = select(new String[] {}, new String[] {});

		return fetchProfileRows(cr);
	}

	/**
	 * Calculate BMI
	 * 
	 * @return BMI of the user, -1 on Failure
	 */
	public BigDecimal calculateBMI() {
		
		if ((this.getByAttribute("height") != null)
				&& this.getByAttribute("weight") != null) {
			// BMI = mass(lb) * 703 / (height(in) ^ 2)
			double mass = Double
					.parseDouble(this.getByAttribute("weight").value);
			double height = Double
					.parseDouble(this.getByAttribute("height").value);
			
			// Preventing division by 0
			if(height == 0){
				return (BigDecimal.valueOf(0));
			}
			
			return (BigDecimal.valueOf(mass * 703 / (height * height)));
		} 
		else{
			return BigDecimal.valueOf(-1);
		}
	}

}