<?php namespace Illuminate\Database\Schema\Grammars;

use Illuminate\Support\Fluent;
use Illuminate\Database\Connection;
use Illuminate\Database\Schema\Blueprint;

class SQLiteGrammar extends Grammar
{

    /**
     * The possible column modifiers.
     *
     * @var array
     */
    protected $modifiers = array('Nullable', 'Default', 'Increment');

    /**
     * The columns available as serials.
     *
     * @var array
     */
    protected $serials = array('bigInteger', 'integer');

    /**
     * Compile the query to determine if a table exists.
     *
     * @return string
     */
    public function compileTableExists()
    {
        return "select * from sqlite_master where type = 'table' and name = ?";
    }

    /**
     * Compile the query to determine the list of columns.
     *
     * @param  string $table
     * @return string
     */
    public function compileColumnExists($table)
    {
        return 'pragma table_info(' . str_replace('.', '__', $table) . ')';
    }

    /**
     * Compile a create table command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileCreate(Blueprint $blueprint, Fluent $command)
    {
        $columns = implode(', ', $this->getColumns($blueprint));

        $sql = 'create table ' . $this->wrapTable($blueprint) . " ($columns";

        // SQLite forces primary keys to be added when the table is initially created
        // so we will need to check for a primary key commands and add the columns
        // to the table's declaration here so they can be created on the tables.
        $sql .= (string)$this->addForeignKeys($blueprint);

        $sql .= (string)$this->addPrimaryKeys($blueprint);

        return $sql . ')';
    }

    /**
     * Get the foreign key syntax for a table creation statement.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @return string|null
     */
    protected function addForeignKeys(Blueprint $blueprint)
    {
        $sql = '';

        $foreigns = $this->getCommandsByName($blueprint, 'foreign');

        // Once we have all the foreign key commands for the table creation statement
        // we'll loop through each of them and add them to the create table SQL we
        // are building, since SQLite needs foreign keys on the tables creation.
        foreach ($foreigns as $foreign) {
            $sql .= $this->getForeignKey($foreign);

            if (!is_null($foreign->onDelete)) {
                $sql .= " on delete {$foreign->onDelete}";
            }

            if (!is_null($foreign->onUpdate)) {
                $sql .= " on update {$foreign->onUpdate}";
            }
        }

        return $sql;
    }

    /**
     * Get the SQL for the foreign key.
     *
     * @param  \Illuminate\Support\Fluent $foreign
     * @return string
     */
    protected function getForeignKey($foreign)
    {
        $on = $this->wrapTable($foreign->on);

        // We need to columnize the columns that the foreign key is being defined for
        // so that it is a properly formatted list. Once we have done this, we can
        // return the foreign key SQL declaration to the calling method for use.
        $columns = $this->columnize($foreign->columns);

        $onColumns = $this->columnize((array)$foreign->references);

        return ", foreign key($columns) references $on($onColumns)";
    }

    /**
     * Get the primary key syntax for a table creation statement.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @return string|null
     */
    protected function addPrimaryKeys(Blueprint $blueprint)
    {
        $primary = $this->getCommandByName($blueprint, 'primary');

        if (!is_null($primary)) {
            $columns = $this->columnize($primary->columns);

            return ", primary key ({$columns})";
        }
    }

    /**
     * Compile alter table commands for adding columns.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return array
     */
    public function compileAdd(Blueprint $blueprint, Fluent $command)
    {
        $table = $this->wrapTable($blueprint);

        $columns = $this->prefixArray('add column', $this->getColumns($blueprint));

        $statements = array();

        foreach ($columns as $column) {
            $statements[] = 'alter table ' . $table . ' ' . $column;
        }

        return $statements;
    }

    /**
     * Compile a unique key command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileUnique(Blueprint $blueprint, Fluent $command)
    {
        $columns = $this->columnize($command->columns);

        $table = $this->wrapTable($blueprint);

        return "create unique index {$command->index} on {$table} ({$columns})";
    }

    /**
     * Compile a plain index key command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileIndex(Blueprint $blueprint, Fluent $command)
    {
        $columns = $this->columnize($command->columns);

        $table = $this->wrapTable($blueprint);

        return "create index {$command->index} on {$table} ({$columns})";
    }

    /**
     * Compile a foreign key command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileForeign(Blueprint $blueprint, Fluent $command)
    {
        // Handled on table creation...
    }

    /**
     * Compile a drop table command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileDrop(Blueprint $blueprint, Fluent $command)
    {
        return 'drop table ' . $this->wrapTable($blueprint);
    }

    /**
     * Compile a drop table (if exists) command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileDropIfExists(Blueprint $blueprint, Fluent $command)
    {
        return 'drop table if exists ' . $this->wrapTable($blueprint);
    }

    /**
     * Compile a drop column command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @param  \Illuminate\Database\Connection $connection
     * @return array
     */
    public function compileDropColumn(Blueprint $blueprint, Fluent $command, Connection $connection)
    {
        $schema = $connection->getDoctrineSchemaManager();

        $tableDiff = $this->getDoctrineTableDiff($blueprint, $schema);

        foreach ($command->columns as $name) {
            $column = $connection->getDoctrineColumn($blueprint->getTable(), $name);

            $tableDiff->removedColumns[$name] = $column;
        }

        return (array)$schema->getDatabasePlatform()->getAlterTableSQL($tableDiff);
    }

    /**
     * Compile a drop unique key command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileDropUnique(Blueprint $blueprint, Fluent $command)
    {
        return "drop index {$command->index}";
    }

    /**
     * Compile a drop index command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileDropIndex(Blueprint $blueprint, Fluent $command)
    {
        return "drop index {$command->index}";
    }

    /**
     * Compile a rename table command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileRename(Blueprint $blueprint, Fluent $command)
    {
        $from = $this->wrapTable($blueprint);

        return "alter table {$from} rename to " . $this->wrapTable($command->to);
    }

    /**
     * Create the column definition for a char type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeChar(Fluent $column)
    {
        return 'varchar';
    }

    /**
     * Create the column definition for a string type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeString(Fluent $column)
    {
        return 'varchar';
    }

    /**
     * Create the column definition for a text type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeText(Fluent $column)
    {
        return 'text';
    }

    /**
     * Create the column definition for a medium text type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeMediumText(Fluent $column)
    {
        return 'text';
    }

    /**
     * Create the column definition for a long text type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeLongText(Fluent $column)
    {
        return 'text';
    }

    /**
     * Create the column definition for a integer type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeInteger(Fluent $column)
    {
        return 'integer';
    }

    /**
     * Create the column definition for a big integer type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeBigInteger(Fluent $column)
    {
        return 'integer';
    }

    /**
     * Create the column definition for a medium integer type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeMediumInteger(Fluent $column)
    {
        return 'integer';
    }

    /**
     * Create the column definition for a tiny integer type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTinyInteger(Fluent $column)
    {
        return 'integer';
    }

    /**
     * Create the column definition for a small integer type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeSmallInteger(Fluent $column)
    {
        return 'integer';
    }

    /**
     * Create the column definition for a float type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeFloat(Fluent $column)
    {
        return 'float';
    }

    /**
     * Create the column definition for a double type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeDouble(Fluent $column)
    {
        return 'float';
    }

    /**
     * Create the column definition for a decimal type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeDecimal(Fluent $column)
    {
        return 'numeric';
    }

    /**
     * Create the column definition for a boolean type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeBoolean(Fluent $column)
    {
        return 'tinyint';
    }

    /**
     * Create the column definition for an enum type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeEnum(Fluent $column)
    {
        return 'varchar';
    }

    /**
     * Create the column definition for a json type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeJson(Fluent $column)
    {
        return 'text';
    }

    /**
     * Create the column definition for a jsonb type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeJsonb(Fluent $column)
    {
        return 'text';
    }

    /**
     * Create the column definition for a date type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeDate(Fluent $column)
    {
        return 'date';
    }

    /**
     * Create the column definition for a date-time type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeDateTime(Fluent $column)
    {
        return 'datetime';
    }

    /**
     * Create the column definition for a date-time type.
     *
     * Note: "SQLite does not have a storage class set aside for storing dates and/or times."
     * @link https://www.sqlite.org/datatype3.html
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeDateTimeTz(Fluent $column)
    {
        return 'datetime';
    }

    /**
     * Create the column definition for a time type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTime(Fluent $column)
    {
        return 'time';
    }

    /**
     * Create the column definition for a time type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTimeTz(Fluent $column)
    {
        return 'time';
    }

    /**
     * Create the column definition for a timestamp type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTimestamp(Fluent $column)
    {
        return 'datetime';
    }

    /**
     * Create the column definition for a timestamp type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTimestampTz(Fluent $column)
    {
        return 'datetime';
    }

    /**
     * Create the column definition for a binary type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeBinary(Fluent $column)
    {
        return 'blob';
    }

    /**
     * Get the SQL for a nullable column modifier.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $column
     * @return string|null
     */
    protected function modifyNullable(Blueprint $blueprint, Fluent $column)
    {
        return $column->nullable ? ' null' : ' not null';
    }

    /**
     * Get the SQL for a default column modifier.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $column
     * @return string|null
     */
    protected function modifyDefault(Blueprint $blueprint, Fluent $column)
    {
        if (!is_null($column->default)) {
            return " default " . $this->getDefaultValue($column->default);
        }
    }

    /**
     * Get the SQL for an auto-increment column modifier.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $column
     * @return string|null
     */
    protected function modifyIncrement(Blueprint $blueprint, Fluent $column)
    {
        if (in_array($column->type, $this->serials) && $column->autoIncrement) {
            return ' primary key autoincrement';
        }
    }

}