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

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

class PostgresGrammar extends Grammar
{

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

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

    /**
     * Compile the query to determine if a table exists.
     *
     * @return string
     */
    public function compileTableExists()
    {
        return 'select * from information_schema.tables where table_name = ?';
    }

    /**
     * Compile the query to determine the list of columns.
     *
     * @param  string $table
     * @return string
     */
    public function compileColumnExists($table)
    {
        return "select column_name from information_schema.columns where table_name = '$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));

        return 'create table ' . $this->wrapTable($blueprint) . " ($columns)";
    }

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

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

        return 'alter table ' . $table . ' ' . implode(', ', $columns);
    }

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

        return 'alter table ' . $this->wrapTable($blueprint) . " add primary key ({$columns})";
    }

    /**
     * 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)
    {
        $table = $this->wrapTable($blueprint);

        $columns = $this->columnize($command->columns);

        return "alter table $table add constraint {$command->index} unique ($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);

        return "create index {$command->index} on " . $this->wrapTable($blueprint) . " ({$columns})";
    }

    /**
     * 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
     * @return string
     */
    public function compileDropColumn(Blueprint $blueprint, Fluent $command)
    {
        $columns = $this->prefixArray('drop column', $this->wrapArray($command->columns));

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

        return 'alter table ' . $table . ' ' . implode(', ', $columns);
    }

    /**
     * Compile a drop primary key command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileDropPrimary(Blueprint $blueprint, Fluent $command)
    {
        $table = $blueprint->getTable();

        return 'alter table ' . $this->wrapTable($blueprint) . " drop constraint {$table}_pkey";
    }

    /**
     * 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)
    {
        $table = $this->wrapTable($blueprint);

        return "alter table {$table} drop constraint {$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 drop foreign key command.
     *
     * @param  \Illuminate\Database\Schema\Blueprint $blueprint
     * @param  \Illuminate\Support\Fluent $command
     * @return string
     */
    public function compileDropForeign(Blueprint $blueprint, Fluent $command)
    {
        $table = $this->wrapTable($blueprint);

        return "alter table {$table} drop constraint {$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 $column)
    {
        return "char({$column->length})";
    }

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

    /**
     * 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 $column->autoIncrement ? 'serial' : 'integer';
    }

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

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

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

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

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

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

    /**
     * Create the column definition for a decimal type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeDecimal(Fluent $column)
    {
        return "decimal({$column->total}, {$column->places})";
    }

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

    /**
     * Create the column definition for an enum type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeEnum(Fluent $column)
    {
        $allowed = array_map(function ($a) {
            return "'" . $a . "'";
        }, $column->allowed);

        return "varchar(255) check (\"{$column->name}\" in (" . implode(', ', $allowed) . "))";
    }

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

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

    /**
     * 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 'timestamp(0) without time zone';
    }

    /**
     * Create the column definition for a date-time type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeDateTimeTz(Fluent $column)
    {
        return 'timestamp(0) with time zone';
    }

    /**
     * Create the column definition for a time type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTime(Fluent $column)
    {
        return 'time(0) without time zone';
    }

    /**
     * Create the column definition for a time type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTimeTz(Fluent $column)
    {
        return 'time(0) with time zone';
    }

    /**
     * Create the column definition for a timestamp type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTimestamp(Fluent $column)
    {
        return 'timestamp(0) without time zone';
    }

    /**
     * Create the column definition for a timestamp type.
     *
     * @param  \Illuminate\Support\Fluent $column
     * @return string
     */
    protected function typeTimestampTz(Fluent $column)
    {
        return 'timestamp(0) with time zone';
    }

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

    /**
     * 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';
        }
    }

}