/*
 * Copyright 2017 Hippo Seven
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hippo.database;

/*
 * Created by Hippo on 2017/9/3.
 */

import android.content.Context;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.SparseArray;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MSQLiteBuilder {

    public static final String COLUMN_ID = "_id";

    private static final Map<Class, String> JAVA_TYPE_TO_SQLITE_TYPE = new HashMap<>();

    static {
        JAVA_TYPE_TO_SQLITE_TYPE.put(boolean.class, "INTEGER NOT NULL DEFAULT 0");
        JAVA_TYPE_TO_SQLITE_TYPE.put(byte.class, "INTEGER NOT NULL DEFAULT 0");
        JAVA_TYPE_TO_SQLITE_TYPE.put(short.class, "INTEGER NOT NULL DEFAULT 0");
        JAVA_TYPE_TO_SQLITE_TYPE.put(int.class, "INTEGER NOT NULL DEFAULT 0");
        JAVA_TYPE_TO_SQLITE_TYPE.put(long.class, "INTEGER NOT NULL DEFAULT 0");
        JAVA_TYPE_TO_SQLITE_TYPE.put(float.class, "REAL NOT NULL DEFAULT 0");
        JAVA_TYPE_TO_SQLITE_TYPE.put(double.class, "REAL NOT NULL DEFAULT 0");
        JAVA_TYPE_TO_SQLITE_TYPE.put(String.class, "TEXT");
    }

    private final SparseArray<List<String>> statementsMap = new SparseArray<>();
    private int version = 0;
    private List<String> statements;

    private static String javaTypeToSQLiteType(Class clazz) {
        String type = JAVA_TYPE_TO_SQLITE_TYPE.get(clazz);
        if (type == null) {
            throw new IllegalStateException("Unknown type: " + clazz);
        }
        return type;
    }

    /**
     * Bump database version.
     */
    public MSQLiteBuilder version(int version) {
        if (version <= this.version) {
            throw new IllegalStateException("New version must be bigger than current version. "
                    + "current version: " + this.version + ", new version: " + version + ".");
        }
        this.version = version;
        this.statements = new ArrayList<>();
        this.statementsMap.put(version, this.statements);
        return this;
    }

    /**
     * Creates a table with int {@link #COLUMN_ID} primary key.
     */
    public MSQLiteBuilder createTable(String table) {
        return createTable(table, COLUMN_ID, int.class);
    }

    /**
     * Creates a table.
     */
    public MSQLiteBuilder createTable(String table, String column, Class clazz) {
        return statement("CREATE TABLE " + table + " (" + column + " " + javaTypeToSQLiteType(clazz) + " PRIMARY KEY);");
    }

    /**
     * Drops a table.
     */
    public MSQLiteBuilder dropTable(String table) {
        return statement("DROP TABLE " + table + ";");
    }

    /**
     * Inserts a column to the table.
     */
    public MSQLiteBuilder insertColumn(String table, String column, Class clazz) {
        return statement("ALTER TABLE " + table + " ADD COLUMN " + column + " " + javaTypeToSQLiteType(clazz) + ";");
    }

    /**
     * Add a statement.
     */
    public MSQLiteBuilder statement(String statement) {
        if (version == 0 || statements == null) {
            throw new IllegalStateException("Call version() first!");
        }
        statements.add(statement);
        return this;
    }

    /**
     * Build a SQLiteOpenHelper from it.
     */
    public SQLiteOpenHelper build(Context context, String name, int version) {
        return new MSQLiteOpenHelper(context, name, version, this);
    }

    List<String> getStatements(int oldVersion, int newVersion) {
        List<String> result = new ArrayList<>();
        for (int i = oldVersion + 1; i <= newVersion; ++i) {
            List<String> list = statementsMap.get(i);
            if (list != null) {
                result.addAll(list);
            }
        }
        return result;
    }
}