// Copyright 2015-2019 Parity Technologies (UK) Ltd.
// This file is part of Parity Ethereum.

// Parity Ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// Parity Ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with Parity Ethereum.  If not, see <http://www.gnu.org/licenses/>.

//! Tests for migrations.
//! A random temp directory is created. A database is created within it, and migrations
//! are performed in temp sub-directories.

#[macro_use]
extern crate macros;
extern crate kvdb_rocksdb;
extern crate migration_rocksdb as migration;
extern crate tempdir;

use kvdb_rocksdb::Database;
use migration::{Batch, ChangeColumns, Config, Manager, Migration, SimpleMigration};
use std::{
    collections::BTreeMap,
    io,
    path::{Path, PathBuf},
    sync::Arc,
};
use tempdir::TempDir;

#[inline]
fn db_path(path: &Path) -> PathBuf {
    path.join("db")
}

// initialize a database at the given directory with the given values.
fn make_db(path: &Path, pairs: BTreeMap<Vec<u8>, Vec<u8>>) {
    let db = Database::open_default(path.to_str().unwrap()).expect("failed to open temp database");
    {
        let mut transaction = db.transaction();
        for (k, v) in pairs {
            transaction.put(None, &k, &v);
        }

        db.write(transaction)
            .expect("failed to write db transaction");
    }
}

// helper for verifying a migrated database.
fn verify_migration(path: &Path, pairs: BTreeMap<Vec<u8>, Vec<u8>>) {
    let db = Database::open_default(path.to_str().unwrap()).unwrap();

    for (k, v) in pairs {
        let x = db.get(None, &k).unwrap().unwrap();

        assert_eq!(&x[..], &v[..]);
    }
}

struct Migration0;

impl SimpleMigration for Migration0 {
    fn columns(&self) -> Option<u32> {
        None
    }

    fn version(&self) -> u32 {
        1
    }

    fn migrated_column_index(&self) -> Option<u32> {
        None
    }

    fn simple_migrate(
        &mut self,
        mut key: Vec<u8>,
        mut value: Vec<u8>,
    ) -> Option<(Vec<u8>, Vec<u8>)> {
        key.push(0x11);
        value.push(0x22);

        Some((key, value))
    }
}

struct Migration1;

impl SimpleMigration for Migration1 {
    fn columns(&self) -> Option<u32> {
        None
    }

    fn version(&self) -> u32 {
        2
    }

    fn migrated_column_index(&self) -> Option<u32> {
        None
    }

    fn simple_migrate(&mut self, key: Vec<u8>, _value: Vec<u8>) -> Option<(Vec<u8>, Vec<u8>)> {
        Some((key, vec![]))
    }
}

struct AddsColumn;

impl Migration for AddsColumn {
    fn pre_columns(&self) -> Option<u32> {
        None
    }

    fn columns(&self) -> Option<u32> {
        Some(1)
    }

    fn version(&self) -> u32 {
        1
    }

    fn migrate(
        &mut self,
        source: Arc<Database>,
        config: &Config,
        dest: &mut Database,
        col: Option<u32>,
    ) -> io::Result<()> {
        let mut batch = Batch::new(config, col);

        for (key, value) in source.iter(col).into_iter().flat_map(|inner| inner) {
            batch.insert(key.into_vec(), value.into_vec(), dest)?;
        }

        if col == Some(1) {
            batch.insert(vec![1, 2, 3], vec![4, 5, 6], dest)?;
        }

        batch.commit(dest)
    }
}

#[test]
fn one_simple_migration() {
    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());
    let mut manager = Manager::new(Config::default());
    make_db(&db_path, map![vec![] => vec![], vec![1] => vec![1]]);
    let expected = map![vec![0x11] => vec![0x22], vec![1, 0x11] => vec![1, 0x22]];

    manager.add_migration(Migration0).unwrap();
    let end_path = manager.execute(&db_path, 0).unwrap();

    verify_migration(&end_path, expected);
}

#[test]
#[should_panic]
fn no_migration_needed() {
    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());
    let mut manager = Manager::new(Config::default());
    make_db(&db_path, map![vec![] => vec![], vec![1] => vec![1]]);

    manager.add_migration(Migration0).unwrap();
    manager.execute(&db_path, 1).unwrap();
}

#[test]
#[should_panic]
fn wrong_adding_order() {
    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());
    let mut manager = Manager::new(Config::default());
    make_db(&db_path, map![vec![] => vec![], vec![1] => vec![1]]);

    manager.add_migration(Migration1).unwrap();
    manager.add_migration(Migration0).unwrap();
}

#[test]
fn multiple_migrations() {
    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());
    let mut manager = Manager::new(Config::default());
    make_db(&db_path, map![vec![] => vec![], vec![1] => vec![1]]);
    let expected = map![vec![0x11] => vec![], vec![1, 0x11] => vec![]];

    manager.add_migration(Migration0).unwrap();
    manager.add_migration(Migration1).unwrap();
    let end_path = manager.execute(&db_path, 0).unwrap();

    verify_migration(&end_path, expected);
}

#[test]
fn second_migration() {
    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());
    let mut manager = Manager::new(Config::default());
    make_db(&db_path, map![vec![] => vec![], vec![1] => vec![1]]);
    let expected = map![vec![] => vec![], vec![1] => vec![]];

    manager.add_migration(Migration0).unwrap();
    manager.add_migration(Migration1).unwrap();
    let end_path = manager.execute(&db_path, 1).unwrap();

    verify_migration(&end_path, expected);
}

#[test]
fn first_and_noop_migration() {
    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());
    let mut manager = Manager::new(Config::default());
    make_db(&db_path, map![vec![] => vec![], vec![1] => vec![1]]);
    let expected = map![vec![0x11] => vec![0x22], vec![1, 0x11] => vec![1, 0x22]];

    manager.add_migration(Migration0).unwrap();
    let end_path = manager.execute(&db_path, 0).unwrap();

    verify_migration(&end_path, expected);
}

#[test]
fn noop_and_second_migration() {
    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());
    let mut manager = Manager::new(Config::default());
    make_db(&db_path, map![vec![] => vec![], vec![1] => vec![1]]);
    let expected = map![vec![] => vec![], vec![1] => vec![]];

    manager.add_migration(Migration1).unwrap();
    let end_path = manager.execute(&db_path, 0).unwrap();

    verify_migration(&end_path, expected);
}

#[test]
fn is_migration_needed() {
    let mut manager = Manager::new(Config::default());
    manager.add_migration(Migration0).unwrap();
    manager.add_migration(Migration1).unwrap();

    assert!(manager.is_needed(0));
    assert!(manager.is_needed(1));
    assert!(!manager.is_needed(2));
}

#[test]
fn pre_columns() {
    let mut manager = Manager::new(Config::default());
    manager.add_migration(AddsColumn).unwrap();

    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());

    // this shouldn't fail to open the database even though it's one column
    // short of the one before it.
    manager.execute(&db_path, 0).unwrap();
}

#[test]
fn change_columns() {
    use kvdb_rocksdb::DatabaseConfig;

    let mut manager = Manager::new(Config::default());
    manager
        .add_migration(ChangeColumns {
            pre_columns: None,
            post_columns: Some(4),
            version: 1,
        })
        .unwrap();

    let tempdir = TempDir::new("").unwrap();
    let db_path = db_path(tempdir.path());

    let new_path = manager.execute(&db_path, 0).unwrap();

    assert_eq!(
        db_path, new_path,
        "Changing columns is an in-place migration."
    );

    let config = DatabaseConfig::with_columns(Some(4));
    let db = Database::open(&config, new_path.to_str().unwrap()).unwrap();
    assert_eq!(db.num_columns(), 4);
}