From 4203b21097fbbb363663ec0634ccb086ff6ecca0 Mon Sep 17 00:00:00 2001
From: Dmitriy Pleshevskiy <dmitriy@ideascup.me>
Date: Sat, 20 Aug 2022 15:24:17 +0300
Subject: [PATCH] repo/sqlite: add migration mechanism

---
 src/main.rs        |  6 +++-
 src/repo/sqlite.rs | 77 ++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 70 insertions(+), 13 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 246456c..1ee17d8 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -40,9 +40,13 @@ fn main() {
     let xdg_dirs = BaseDirectories::with_prefix(env!("CARGO_PKG_NAME")).unwrap();
     let repo = match SqliteRepo::new(xdg_dirs) {
         Ok(repo) => repo,
-        Err(err) => return eprintln!("Cannot connect to repository: {}", err),
+        Err(err) => return eprintln!("Cannot connect to repository: {err}"),
     };
 
+    if let Err(err) = repo.upgrade() {
+        return eprintln!("Cannot upgrade database: {err}");
+    }
+
     match args.command {
         cli::SubCommand::Add(args) => {
             cli::add::execute(repo, args);
diff --git a/src/repo/sqlite.rs b/src/repo/sqlite.rs
index 920824c..89dbb51 100644
--- a/src/repo/sqlite.rs
+++ b/src/repo/sqlite.rs
@@ -62,18 +62,6 @@ impl SqliteRepo {
         let file_path = xdg_dirs.get_data_file(SCHEMA_FILE);
         let conn = Connection::open(file_path).map_err(|_| Error::Connect)?;
 
-        /*
-        conn.execute_batch(&format!(
-            "BEGIN; {} COMMIT;",
-            include_str!("../../database/schema.sql")
-        ))
-        .map_err(|err| match err {
-            rusqlite::Error::SqlInputError { .. } => panic!("{}", err),
-            _ => err,
-        })
-        .ok();
-        */
-
         Ok(Self { conn })
     }
 }
@@ -261,3 +249,68 @@ impl SqliteRepo {
         Ok(row)
     }
 }
+
+macro_rules! run_migration {
+    ($this:ident, $ver:ident = $version:expr) => {
+        $this
+            .conn
+            .execute_batch(&format!(
+                "BEGIN; {} COMMIT;",
+                include_str!(concat!("../../database/migrations/", $version, ".sql"))
+            ))
+            .map_err(|_| MigrationError::Upgrade)?;
+
+        $ver.replace($version);
+    };
+}
+
+// TODO: move migration to a separate repository.
+#[derive(Debug)]
+pub enum MigrationError {
+    Upgrade,
+    DeleteInfo,
+    InsertInfo,
+}
+
+impl std::fmt::Display for MigrationError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            MigrationError::Upgrade => f.write_str("Cannot upgrade the migration to a new version"),
+            MigrationError::DeleteInfo => {
+                f.write_str("Cannot delete the tas info from the database")
+            }
+            MigrationError::InsertInfo => {
+                f.write_str("Cannot insert a new tas information to the database")
+            }
+        }
+    }
+}
+
+impl std::error::Error for MigrationError {}
+
+impl SqliteRepo {
+    pub fn upgrade(&self) -> Result<(), MigrationError> {
+        let mut version = self.version();
+        if version.is_none() {
+            run_migration!(self, version = 202208162308);
+        }
+
+        self.conn
+            .execute("DELETE FROM _tas_info", [])
+            .map_err(|_| MigrationError::DeleteInfo)?;
+        self.conn
+            .execute(
+                "INSERT INTO _tas_info (version) VALUES (?)",
+                [version.unwrap()],
+            )
+            .map_err(|_| MigrationError::InsertInfo)?;
+
+        Ok(())
+    }
+
+    fn version(&self) -> Option<i64> {
+        self.conn
+            .query_row("SELECT version FROM _tas_info", [], |r| r.get("version"))
+            .unwrap_or_default()
+    }
+}