From 8256ab5dd901904dfa8f78ebc3f3ed08a969226d Mon Sep 17 00:00:00 2001
From: Andrew Dolgov <noreply@fakecake.org>
Date: Wed, 3 Mar 2021 23:38:52 +0300
Subject: wip: initial for db_migrations

---
 classes/db/migrations.php | 140 ++++++++++++++++++++++++++++++++++++++++++++++
 classes/pluginhost.php    |   7 ++-
 2 files changed, 146 insertions(+), 1 deletion(-)
 create mode 100644 classes/db/migrations.php

diff --git a/classes/db/migrations.php b/classes/db/migrations.php
new file mode 100644
index 000000000..d1eee61d3
--- /dev/null
+++ b/classes/db/migrations.php
@@ -0,0 +1,140 @@
+<?php
+class Db_Migrations {
+
+	private $base_filename = "schema.sql";
+	private $base_path;
+	private $migrations_path;
+	private $migrations_table;
+	private $pdo;
+
+	private $cached_version;
+	private $cached_max_version;
+
+	function initialize_for_plugin(Plugin $plugin, string $schema_suffix = "sql") {
+		$plugin_dir = PluginHost::getInstance()->get_plugin_dir($plugin);
+		$this->initialize($plugin_dir . "/${schema_suffix}",
+			strtolower("ttrss_migrations_plugin_" . get_class($plugin)));
+	}
+
+	function initialize(string $root_path, string $migrations_table) {
+		$this->base_path = "$root_path/" . Config::get(Config::DB_TYPE);
+		$this->migrations_path = $this->base_path . "/migrations";
+
+		$this->migrations_table = $migrations_table;
+	}
+
+	function __construct() {
+		$this->pdo = Db::pdo();
+	}
+
+	private function set_version(int $version) {
+		$sth = $this->pdo->query("SELECT * FROM {$this->migrations_table}");
+
+		if ($res = $sth->fetch()) {
+			$sth = $this->pdo->prepare("UPDATE {$this->migrations_table} SET schema_version = ?");
+		} else {
+			$sth = $this->pdo->prepare("INSERT INTO {$this->migrations_table} (schema_version) VALUES (?)");
+		}
+
+		$sth->execute([$version]);
+
+		$this->cached_version = $version;
+	}
+
+	private function get_version() : int {
+		if (isset($this->cached_version))
+			return $this->cached_version;
+
+		try {
+			$sth = $this->pdo->query("SELECT * FROM {$this->migrations_table}");
+
+			if ($res = $sth->fetch()) {
+				return (int) $res['schema_version'];
+			} else {
+				return -1;
+			}
+		} catch (PDOException $e) {
+			$this->create_migrations_table();
+
+			return -1;
+		}
+	}
+
+	private function create_migrations_table() {
+		$this->pdo->query("CREATE TABLE IF NOT EXISTS {$this->migrations_table} (schema_version integer not null)");
+	}
+
+	private function migrate_to(int $version) {
+		try {
+			$this->pdo->beginTransaction();
+
+			foreach ($this->get_lines($version) as $line) {
+				$this->pdo->query($line);
+			}
+
+			$this->set_version($version);
+
+			$this->pdo->commit();
+		} catch (PDOException $e) {
+			try {
+				$this->pdo->rollback();
+			} catch (PDOException $ie) {
+				//
+			}
+			throw $e;
+		}
+	}
+
+	private function get_max_version() : int {
+		if (isset($this->cached_max_version))
+			return $this->cached_max_version;
+
+		$migrations = glob("{$this->migrations_path}/*.sql");
+
+		if (count($migrations) > 0) {
+			natsort($migrations);
+
+			$this->cached_max_version = (int) basename(array_pop($migrations), ".sql");
+
+		} else {
+			$this->cached_max_version = 0;
+		}
+
+		return $this->cached_max_version;
+	}
+
+	function migrate() : bool {
+
+		for ($i = $this->get_version() + 1; $i <= $this->get_max_version(); $i++)
+			try {
+				$this->migrate_to($i);
+			} catch (PDOException $e) {
+				user_error("Failed applying migration $i on table {$this->migrations_table}: " . $e->getMessage(), E_USER_WARNING);
+				//throw $e;
+			}
+
+		return $this->get_version() == $this->get_max_version();
+	}
+
+	private function get_lines(int $version) : array {
+		if ($version > 0)
+			$filename = "{$this->migrations_path}/${version}.sql";
+		else
+			$filename = "{$this->base_path}/{$this->base_filename}";
+
+		if (file_exists($filename)) {
+			$lines =	array_filter(preg_split("/[\r\n]/", file_get_contents($filename)),
+							function ($line) {
+								return strlen(trim($line)) > 0 && strpos($line, "--") !== 0;
+							});
+
+			return array_filter(explode(";", implode("", $lines)), function ($line) {
+				return strlen(trim($line)) > 0;
+			});
+
+		} else {
+			user_error(E_USER_ERROR, "[migrations] requested schema file ${filename} not found.");
+			return [];
+		}
+	}
+}
diff --git a/classes/pluginhost.php b/classes/pluginhost.php
index 746b780e4..366e2b2d3 100755
--- a/classes/pluginhost.php
+++ b/classes/pluginhost.php
@@ -624,9 +624,14 @@ class PluginHost {
 		}
 	}
 
-	function is_local(Plugin $plugin) {
+	function get_plugin_dir(Plugin $plugin) {
 		$ref = new ReflectionClass(get_class($plugin));
+		return dirname($ref->getFileName());
+	}
 
+	// TODO: use get_plugin_dir()
+	function is_local(Plugin $plugin) {
+		$ref = new ReflectionClass(get_class($plugin));
 		return basename(dirname(dirname($ref->getFileName()))) == "plugins.local";
 	}
 }
-- 
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