AppInfo.java

package org.kvj.lima1.sync.controller.data;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import org.json.JSONException;
import org.json.JSONObject;
import org.kvj.bravo7.ApplicationContext;
import org.kvj.bravo7.SuperActivity;

import android.text.TextUtils;
import android.util.Log;

public class AppInfo {
	private static final String TAG = "AppInfo";
	public AppDBHelper db = null;
	public String name = null;
	private long id = 0;
	public JSONObject schema = null;
	public SchemaInfo schemaInfo = null;
	private ApplicationContext context;
	private File folderName = null;

	public AppInfo(ApplicationContext context, String name) {
		this.name = name;
		this.context = context;
		db = new AppDBHelper(context, name + "-app.db");
		if (!db.open()) {
			db = null;
		}
		String json = context.getStringPreference(name + "-schema", "");
		// json =
		// "{\"_rev\":2,\"_fkeys\":[{\"pk\":\"notepads.id\",\"fk\":\"sheets.notepad_id\"},{\"pk\":\"templates.id\",\"fk\":\"sheets.template_id\"},{\"pk\":\"sheets.id\",\"fk\":\"notes.sheet_id\"},{\"pk\":\"sheets.id\",\"fk\":\"bookmarks.sheet_id\"}],\"templates\":{\"index\":1,\"texts\":[\"name\",\"tag\"]},\"notepads\":{\"index\":0,\"numbers\":[\"archived\"],\"texts\":[\"name\",\"tag\"]},\"sheets\":{\"index\":2,\"numbers\":[\"template_id\",\"notepad_id\"],\"texts\":[\"title\"],\"indexes\":[[\"notepad_id\"]]},\"notes\":{\"index\":3,\"numbers\":[\"sheet_id\",\"archived\"],\"texts\":[\"text\"],\"indexes\":[[\"sheet_id\",\"archived\"]]},\"bookmarks\":{\"index\":4,\"numbers\":[\"sheet_id\"],\"texts\":[\"name\"],\"indexes\":[[\"sheet_id\"]]}}";
		if (!TextUtils.isEmpty(json)) {
			try {
				schema = new JSONObject(json);
				schemaInfo = parseSchema(schema);
			} catch (Exception e) {
			}
		}
	}

	public synchronized long id() {
		long now = System.currentTimeMillis();
		if (now > id) {
			id = now;
			return id;
		}
		return ++id;
	}

	private SchemaInfo parseSchema(JSONObject schema) throws JSONException {
		SchemaInfo info = new SchemaInfo();
		info.parseSchema(schema);
		return info;
	}

	private List<String> generateAlter(String table, TableInfo oldSchema, TableInfo newSchema) {
		List<String> sqls = new ArrayList<String>();
		for (int i = oldSchema.numbers.size(); i < newSchema.numbers.size(); i++) {
			// New numbers
			sqls.add(generateAlter(table, newSchema.numbers.get(i), "integer"));
		}
		for (int i = oldSchema.texts.size(); i < newSchema.texts.size(); i++) {
			// New texts
			sqls.add(generateAlter(table, newSchema.texts.get(i), "text"));
		}
		for (int i = oldSchema.indexes.size(); i < newSchema.indexes.size(); i++) {
			// New indexes
			sqls.add(createIndex(table, i, newSchema.indexes.get(i)));
		}
		return sqls;
	}

	private String generateAlter(String table, String field, String type) {
		return "alter table t_" + table + " add f_" + field + " " + type;
	}

	private List<String> generateCreate(String table, TableInfo info) {
		List<String> sqls = new ArrayList<String>();
		StringBuffer create = new StringBuffer(
				"create table if not exists t_"
						+ table
						+ " (id integer primary key, status integer default 0, updated integer default 0, own integer default 1, stream text, data text");
		for (String field : info.numbers) { // Add numbers
			create.append(", f_" + field + " integer");
		}
		for (String field : info.texts) { // Add texts
			create.append(", f_" + field + " text");
		}
		create.append(")");
		sqls.add(create.toString());
		for (int i = 0; i < info.indexes.size(); i++) { // Create index
			sqls.add(createIndex(table, i, info.indexes.get(i)));
		}
		return sqls;
	}

	private String createIndex(String table, int index, List<String> fields) {
		StringBuffer create = new StringBuffer("create index i_" + table + "_" + index + " on t_" + table + " (status");
		for (String field : fields) { // Add fields
			create.append(", f_" + field);
		}
		create.append(")");
		return create.toString();
	}

	public String upgradeSchema(JSONObject newSchema) {
		try { // DB and JSON errors
			SchemaInfo newSchemaInfo = new SchemaInfo();
			newSchemaInfo.parseSchema(newSchema);
			Log.i(TAG, "upgradeSchema: " + schemaInfo + ", " + newSchemaInfo);
			if (null == schemaInfo || schemaInfo.revision < newSchemaInfo.revision) {
				// New or upgrades are different
				List<String> sqls = new ArrayList<String>();
				for (String table : newSchemaInfo.tables.keySet()) {
					// Check every table
					if (null == schemaInfo || !schemaInfo.tables.containsKey(table)) {
						// Create table
						sqls.addAll(generateCreate(table, newSchemaInfo.tables.get(table)));
					} else {
						sqls.addAll(generateAlter(table, schemaInfo.tables.get(table), newSchemaInfo.tables.get(table)));
					}
				}
				// Log.i(TAG, "Upgrade: " + sqls);
				for (String sql : sqls) { // Execute SQL
					Log.i(TAG, "Upgrade schema: " + sql);
					db.getDatabase().execSQL(sql);
				}
				schemaInfo = newSchemaInfo;
			}
			return null;
		} catch (Exception e) {
			Log.e(TAG, "Error upgrading schema", e);
			return "Error upgrading DB schema";
		}
	}

	public void setSchema(JSONObject newSchema) {
		schema = newSchema;
		context.setStringPreference(name + "-schema", newSchema.toString());
	}

	public TableInfo getTableInfo(String stream) {
		if (null == db) { // No DB
			return null;
		}
		if (null == schemaInfo) { // Not synchronized
			return null;
		}
		return schemaInfo.tables.get(stream);
	}

	public File getFilesFolder() {
		if (null == folderName) {
			folderName = new File(SuperActivity.getExternalCacheFolder(context), "files" + File.separatorChar + name);
			if (!folderName.exists()) { // Not created yet
				if (!folderName.mkdirs()) { // Failed
					Log.w(TAG, "Error creating cache files folder");
				}
			}
		}
		return folderName;
	}
}