<?php
class Database
{
	public static $handle = null;

	public function __construct($createDatabase = false)
	{
		if (self::$handle === null) {
			self::$handle = new SQLite3(SQLITE_DB);
			self::$handle->enableExceptions(true);
			self::$handle->busyTimeout(60000);

			$initialQueries = [
				"PRAGMA journal_mode = WAL",
				"PRAGMA synchronous = OFF",
				"PRAGMA cache_size = 10000",
				"PRAGMA mmap_size = 30000000000",
				"PRAGMA temp_store = MEMORY",
				"PRAGMA automatic_index = ON",
				"PRAGMA optimize"
			];

			self::$handle->exec(implode(";", $initialQueries) . ";");


			if ($createDatabase === true) {
				$this->createDatabase();
			}
		}
	}

	public function createDatabase()
	{
		$schemaFiles = [
			LIB_MIGRATIONS_DIR . "/_schema.sql",
			MIGRATIONS_DIR . "/_schema.sql"
		];

		foreach ($schemaFiles as $schemaFile) {
			if (file_exists($schemaFile)) {
				$schema = file_get_contents($schemaFile);
				self::$handle->exec($schema);
			}
		}
	}

	public function runMigrations()
	{
		$currentTableVersions = [];

		$result = self::$handle->query("SELECT `table`,`version` FROM `migrations`");
		while ($row = $result->fetchArray(SQLITE3_ASSOC)) {
			$currentTableVersions[$row["table"]] = $row["version"];
		}

		$migrations = [];
		$migrationPaths = [LIB_MIGRATIONS_DIR, MIGRATIONS_DIR];
		foreach ($migrationPaths as $migrationPath) {
			if (is_dir($migrationPath)) {
				$migrations = array_merge($migrations, scandir($migrationPath));
			}
		}

		$migrationCount = 0;

		foreach ($migrations as $migration) {
			if ($migration == "." || $migration == ".." || $migration == "_schema.sql") {
				continue;
			}

			$migrationParts = explode("-", str_replace(".sql", "", $migration));
			$migrationTable = $migrationParts[0];
			$migrationVersion = $migrationParts[1];

			$run = false;

			if (!isset($currentTableVersions[$migrationTable])) {
				$run = true;
			} else {
				if ($migrationVersion > $currentTableVersions[$migrationTable]) {
					$run = true;
				}
			}

			if ($run === true) {
				Logger::log("Found migration for table " . $migrationTable . " version " . $migrationVersion, LOGGER::INFO, "Database");
				$possiblePaths = [LIB_MIGRATIONS_DIR, MIGRATIONS_DIR];
				$migrationFile = null;
				foreach ($possiblePaths as $possiblePath) {
					if (file_exists($possiblePath . "/" . $migration)) {
						$migrationFile = $possiblePath . "/" . $migration;
						break;
					}
				}

				if ($migrationFile === null) {
					Logger::log("Could not find migration file for table " . $migrationTable . " version " . $migrationVersion, LOGGER::ERROR, "Database");
					continue;
				}

				$migrationContents = file_get_contents($migrationFile);
				if (@self::$handle->exec($migrationContents)) {
					self::$handle->exec("INSERT INTO `migrations` (`table`,`version`, `schemafile`, `created`) VALUES ('" . $migrationTable . "'," . $migrationVersion . ",'" . $migration . "', strftime('%Y-%m-%d %H:%M:%S','now'))");
					$migrationCount++;
				} else {
					Logger::log("Failed to run migration for table " . $migrationTable . " version " . $migrationVersion . " with error: " . self::$handle->lastErrorMsg(), LOGGER::ERROR, "Database");
				}
			}
		}

		if ($migrationCount > 0) {
			Logger::log("Ran " . $migrationCount . " migrations", LOGGER::DEBUG, "Database");

			self::$handle->exec("PRAGMA optimize;");
			Logger::log("Optimized database", LOGGER::DEBUG, "Database");
		} else {
			Logger::log("No migrations to run", LOGGER::DEBUG, "Database");
		}
	}

	public function close()
	{
		self::$handle->close();
	}
}