<?php

namespace Kirby\Database\Sql;

use Kirby\Database\Sql;

/**
 * SQLite query builder
 *
 * @package   Kirby Database
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier
 * @license   https://opensource.org/licenses/MIT
 */
class Sqlite extends Sql
{
	/**
	 * Returns a query to list the columns of a specified table;
	 * the query needs to return rows with a column `name`
	 *
	 * @param string $table Table name
	 */
	public function columns(string $table): array
	{
		return [
			'query'    => 'PRAGMA table_info(' . $this->tableName($table) . ')',
			'bindings' => [],
		];
	}

	/**
	 * Abstracted column types to simplify table
	 * creation for multiple database drivers
	 * @codeCoverageIgnore
	 */
	public function columnTypes(): array
	{
		return [
			'id'        => '{{ name }} INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL UNIQUE',
			'varchar'   => '{{ name }} TEXT {{ null }} {{ default }} {{ unique }}',
			'text'      => '{{ name }} TEXT {{ null }} {{ default }} {{ unique }}',
			'int'       => '{{ name }} INTEGER {{ null }} {{ default }} {{ unique }}',
			'timestamp' => '{{ name }} INTEGER {{ null }} {{ default }} {{ unique }}',
			'bool'      => '{{ name }} INTEGER {{ null }} {{ default }} {{ unique }}',
			'float'     => '{{ name }} REAL {{ null }} {{ default }} {{ unique }}',
			'decimal'   => '{{ name }} REAL {{ null }} {{ default }} {{ unique }}'
		];
	}

	/**
	 * Combines an identifier (table and column)
	 *
	 * @param bool $values Whether the identifier is going to be
	 *                     used for a VALUES clause; only relevant
	 *                     for SQLite
	 */
	public function combineIdentifier(string $table, string $column, bool $values = false): string
	{
		// SQLite doesn't support qualified column names for VALUES clauses
		if ($values === true) {
			return $this->quoteIdentifier($column);
		}

		return $this->quoteIdentifier($table) . '.' . $this->quoteIdentifier($column);
	}

	/**
	 * Creates a CREATE TABLE query
	 *
	 * @param string $table Table name
	 * @param array $columns Array of column definition arrays, see `Kirby\Database\Sql::createColumn()`
	 * @return array Array with a `query` string and a `bindings` array
	 */
	public function createTable(string $table, array $columns = []): array
	{
		$inner = $this->createTableInner($columns);

		// add keys
		$keys = [];
		foreach ($inner['keys'] as $key => $columns) {
			// quote each column name and make a list string out of the column names
			$columns = implode(', ', array_map(
				fn ($name) => $this->quoteIdentifier($name),
				$columns
			));

			if ($key === 'primary') {
				$inner['query'] .= ',' . PHP_EOL . 'PRIMARY KEY (' . $columns . ')';
			} else {
				// SQLite only supports index creation using a separate CREATE INDEX query
				$unique = isset($inner['unique'][$key]) === true ? 'UNIQUE ' : '';
				$keys[] = 'CREATE ' . $unique . 'INDEX ' . $this->quoteIdentifier($table . '_index_' . $key) .
							 ' ON ' . $this->quoteIdentifier($table) . ' (' . $columns . ')';
			}
		}

		$query = 'CREATE TABLE ' . $this->quoteIdentifier($table) . ' (' . PHP_EOL . $inner['query'] . PHP_EOL . ')';
		if (empty($keys) === false) {
			$query .= ';' . PHP_EOL . implode(';' . PHP_EOL, $keys);
		}

		return [
			'query'    => $query,
			'bindings' => $inner['bindings']
		];
	}

	/**
	 * Quotes an identifier (table *or* column)
	 */
	public function quoteIdentifier(string $identifier): string
	{
		// * is special
		if ($identifier === '*') {
			return $identifier;
		}

		// escape quotes inside the identifier name
		$identifier = str_replace('"', '""', $identifier);

		// wrap in quotes
		return '"' . $identifier . '"';
	}

	/**
	 * Returns a query to list the tables of the current database;
	 * the query needs to return rows with a column `name`
	 */
	public function tables(): array
	{
		return [
			'query'    => 'SELECT name FROM sqlite_master WHERE type = "table" OR type = "view"',
			'bindings' => []
		];
	}
}
