Pairity/README.md

# Pairity

A partitioned‑model PHP ORM (DTO/DAO) with Query Builder, relations, raw SQL helpers, and a portable migrations + schema builder. Namespace: `Pairity\`. Package: `getphred/pairity`.

## Contributing

This is an early foundation. Contributions, discussions, and design proposals are welcome. Please open an issue to coordinate larger features.

## License

MIT

## Installation

- Requirements: PHP >= 8.1, PDO extension for your database(s)
- Install via Composer:

```
composer require getphred/pairity
```

After install, you can use the CLI at `vendor/bin/pairity`.

## Quick start

Minimal example with SQLite (file db.sqlite) and a simple `users` DAO/DTO.

```php
use Pairity\Database\ConnectionManager;
use Pairity\Model\AbstractDto;
use Pairity\Model\AbstractDao;

// 1) Connect
$conn = ConnectionManager::make([
    'driver' => 'sqlite',
    'path'   => __DIR__ . '/db.sqlite',
]);

// 2) Ensure table exists (demo)
$conn->execute('CREATE TABLE IF NOT EXISTS users (
  id INTEGER PRIMARY KEY AUTOINCREMENT,
  email TEXT NOT NULL,
  name TEXT NULL,
  status TEXT NULL
)');

// 3) Define DTO + DAO
class UserDto extends AbstractDto {}
class UserDao extends AbstractDao {
    public function getTable(): string { return 'users'; }
    protected function dtoClass(): string { return UserDto::class; }
}

// 4) CRUD
$dao = new UserDao($conn);
$created = $dao->insert(['email' => 'a@b.com', 'name' => 'Alice', 'status' => 'active']);
$one = $dao->findById($created->toArray()['id']);
$many = $dao->findAllBy(['status' => 'active']);
$dao->update($created->toArray()['id'], ['name' => 'Alice Updated']);
$dao->deleteById($created->toArray()['id']);
```

For MySQL, configure:

```php
$conn = ConnectionManager::make([
  'driver' => 'mysql',
  'host' => '127.0.0.1',
  'port' => 3306,
  'database' => 'app',
  'username' => 'root',
  'password' => 'secret',
  'charset'  => 'utf8mb4',
]);
```

## Concepts

- DTO (Data Transfer Object): a lightweight data bag. Extend `Pairity\Model\AbstractDto`. Convert to arrays via `toArray(bool $deep = true)`.
- DAO (Data Access Object): table‑focused persistence and relations. Extend `Pairity\Model\AbstractDao` and implement:
  - `getTable(): string`
  - `dtoClass(): string` (class-string of your DTO)
  - Optional: `schema()` for casts, timestamps, soft deletes
  - Optional: `relations()` for `hasOne`/`hasMany`/`belongsTo`
- Relations are DAO‑centric: call `with([...])` to eager load; `load()`/`loadMany()` for lazy.
- Field projection via `fields('id', 'name', 'posts.title')` with dot‑notation for related selects.
- Raw SQL: use `ConnectionInterface::query`, `execute`, `transaction`, `lastInsertId`.
- Query Builder: a simple builder (`Pairity\Query\QueryBuilder`) exists for ad‑hoc SQL composition.

## Dynamic DAO methods

AbstractDao supports dynamic helpers, mapped to column names (Studly/camel to snake_case):

- `findOneBy<Column>($value): ?DTO`
- `findAllBy<Column>($value): DTO[]`
- `updateBy<Column>($value, array $data): int` (returns affected rows)
- `deleteBy<Column>($value): int`

Examples:

```php
$user = $dao->findOneByEmail('a@b.com');
$actives = $dao->findAllByStatus('active');
$dao->updateByEmail('a@b.com', ['name' => 'New Name']);
$dao->deleteByEmail('gone@b.com');
```

## Selecting fields

- Default projection is `SELECT *`.
- Use `fields(...$fields)` to limit columns. You can include relation fields using dot‑notation:

```php
$users = (new UserDao($conn))
  ->fields('id', 'name', 'posts.title')
  ->with(['posts'])
  ->findAllBy(['status' => 'active']);
```

Notes:
- `fields()` affects only the next `find*` call and then resets.
- Relation field selections are passed to the related DAO when eager loading.

## Supported databases

- MySQL/MariaDB
- SQLite
- PostgreSQL
- SQL Server
- Oracle

NoSQL: a minimal in‑memory MongoDB stub is included (`Pairity\NoSql\Mongo\MongoConnectionInterface` and `MongoConnection`) for experimentation without external deps.

## Raw SQL

Use the `ConnectionInterface` behind your DAO for direct SQL.

```php
use Pairity\Contracts\ConnectionInterface;

// Get connection from DAO
$conn = $dao->getConnection();

// SELECT
$rows = $conn->query('SELECT id, email FROM users WHERE status = :s', ['s' => 'active']);

// INSERT/UPDATE/DELETE
$affected = $conn->execute('UPDATE users SET status = :s WHERE id = :id', ['s' => 'inactive', 'id' => 10]);

// Transaction
$conn->transaction(function (ConnectionInterface $db) {
    $db->execute('INSERT INTO logs(message) VALUES(:m)', ['m' => 'started']);
    // ...
});
```

## Relations (DAO‑centric MVP)

Declare relations in your DAO by overriding `relations()` and use `with()` for eager loading or `load()`/`loadMany()` for lazy loading.

Example: `User hasMany Posts`, `Post belongsTo User`

```php
use Pairity\Model\AbstractDto;
use Pairity\Model\AbstractDao;

class UserDto extends AbstractDto {}
class PostDto extends AbstractDto {}

class UserDao extends AbstractDao {
    public function getTable(): string { return 'users'; }
    protected function dtoClass(): string { return UserDto::class; }
    protected function relations(): array {
        return [
            'posts' => [
                'type' => 'hasMany',
                'dao' => PostDao::class,
                'dto' => PostDto::class,
                'foreignKey' => 'user_id', // on posts
                'localKey'   => 'id',      // on users
            ],
        ];
    }
}

class PostDao extends AbstractDao {
    public function getTable(): string { return 'posts'; }
    protected function dtoClass(): string { return PostDto::class; }
    protected function relations(): array {
        return [
            'user' => [
                'type' => 'belongsTo',
                'dao'  => UserDao::class,
                'dto'  => UserDto::class,
                'foreignKey' => 'user_id', // on posts
                'otherKey'   => 'id',      // on users
            ],
        ];
    }
}

$users = (new UserDao($conn))
    ->fields('id', 'name', 'posts.title')
    ->with(['posts'])
    ->findAllBy(['status' => 'active']);

// Lazy load a relation later
$postDao = new PostDao($conn);
$post = $postDao->findOneBy(['id' => 10]);
$postDao->load($post, 'user');
```

Notes:
- Eager loader batches queries using `IN (...)` lookups under the hood.
- Loaded relations are attached onto the DTO under the relation name (e.g., `$user->posts`).
- `hasOne` is supported like `hasMany` but attaches a single DTO instead of a list.

## Model metadata & schema mapping (MVP)

Define schema metadata on your DAO by overriding `schema()`. The schema enables:
- Column casts (storage <-> PHP): `int`, `float`, `bool`, `string`, `datetime`, `json`
- Timestamps automation (`createdAt`, `updatedAt` filled automatically)
- Soft deletes (update `deletedAt` instead of hard delete, with query scopes)

Example:

```php
use Pairity\Model\AbstractDao;

class UserDao extends AbstractDao
{
    public function getTable(): string { return 'users'; }
    protected function dtoClass(): string { return UserDto::class; }

    // Optional: declare primary key, casts, timestamps, soft deletes
    protected function schema(): array
    {
        return [
            'primaryKey' => 'id',
            'columns' => [
                'id' => ['cast' => 'int'],
                'email' => ['cast' => 'string'],
                'name' => ['cast' => 'string'],
                'status' => ['cast' => 'string'],
                // if present in your table
                'data' => ['cast' => 'json'],
                'created_at' => ['cast' => 'datetime'],
                'updated_at' => ['cast' => 'datetime'],
                'deleted_at' => ['cast' => 'datetime'],
            ],
            'timestamps' => [
                'createdAt' => 'created_at',
                'updatedAt' => 'updated_at',
            ],
            'softDeletes' => [
                'enabled' => true,
                'deletedAt' => 'deleted_at',
            ],
        ];
    }
}

// Usage (defaults to SELECT * unless you call fields())
$users = (new UserDao($conn))
    ->findAllBy(['status' => 'active']);

// Soft delete vs hard delete
(new UserDao($conn))->deleteById(10); // if softDeletes enabled => sets deleted_at timestamp

// Query scopes for soft deletes
$all = (new UserDao($conn))->withTrashed()->findAllBy();     // include soft-deleted rows
$trashedOnly = (new UserDao($conn))->onlyTrashed()->findAllBy(); // only soft-deleted

// Casting on hydration and storage
$user = (new UserDao($conn))->findById(1); // date columns become DateTimeImmutable; json becomes array
$created = (new UserDao($conn))->insert([
    'email' => 'a@b.com',
    'name' => 'Alice',
    'status' => 'active',
    'data' => ['tags' => ['a','b']], // stored as JSON automatically
]);
```

### Timestamps & Soft Deletes

- Configure in your DAO `schema()` using keys:
  - `timestamps` → `['createdAt' => 'created_at', 'updatedAt' => 'updated_at']`
  - `softDeletes` → `['enabled' => true, 'deletedAt' => 'deleted_at']`
- Behavior:
  - On `insert()`, both `created_at` and `updated_at` are auto-filled (UTC `Y-m-d H:i:s`).
  - On `update()` and `updateBy()`, `updated_at` is auto-updated.
  - On `deleteById()` / `deleteBy()`, if soft deletes are enabled, rows are marked by setting `deleted_at` instead of being physically removed.
  - Default queries exclude soft-deleted rows. Use scopes `withTrashed()` and `onlyTrashed()` to modify visibility.
  - Helpers:
    - `restoreById($id)` / `restoreBy($criteria)` — set `deleted_at` to NULL.
    - `forceDeleteById($id)` / `forceDeleteBy($criteria)` — permanently delete.
    - `touch($id)` — update only the `updated_at` column.

Example:

```php
$dao = new UserDao($conn);
$user = $dao->insert(['email' => 'x@y.com']); // created_at/updated_at filled
$dao->update($user->id, ['name' => 'Updated']); // updated_at bumped
$dao->deleteById($user->id); // soft delete
$also = $dao->withTrashed()->findById($user->id); // visible with trashed
$dao->restoreById($user->id); // restore
$dao->forceDeleteById($user->id); // permanent
```

## Migrations & Schema Builder

Pairity ships a lightweight migrations runner and a portable schema builder focused on MySQL and SQLite for v1. You can declare migrations as PHP classes implementing `Pairity\Migrations\MigrationInterface` and build tables with a fluent `Schema` builder.

Supported:
- Table operations: `create`, `drop`, `dropIfExists`, `table(...)` (ALTER)
- Columns: `increments`, `bigIncrements`, `integer`, `bigInteger`, `string(varchar)`, `text`, `boolean`, `json`, `datetime`, `decimal(precision, scale)`, `timestamps()`
- Indexes: `primary([...])`, `unique([...], ?name)`, `index([...], ?name)`
- ALTER (MVP): `add column` (all drivers), `drop column` (MySQL, Postgres, SQL Server; SQLite 3.35+), `rename column` (MySQL 8+/Postgres/SQL Server; SQLite 3.25+), `add/drop index/unique`, `rename table`
- Drivers: MySQL/MariaDB (default), SQLite (auto-detected), PostgreSQL (pgsql), SQL Server (sqlsrv), Oracle (oci)

Example migration (see `examples/migrations/CreateUsersTable.php`):

```php
use Pairity\Migrations\MigrationInterface;
use Pairity\Contracts\ConnectionInterface;
use Pairity\Schema\SchemaManager;
use Pairity\Schema\Blueprint;

return new class implements MigrationInterface {
    public function up(ConnectionInterface $connection): void
    {
        $schema = SchemaManager::forConnection($connection);
        $schema->create('users', function (Blueprint $t) {
            $t->increments('id');
            $t->string('email', 190);
            $t->unique(['email']);
            $t->string('name', 255)->nullable();
            $t->string('status', 50)->nullable();
            $t->timestamps();
        });
    }

    public function down(ConnectionInterface $connection): void
    {
        $schema = SchemaManager::forConnection($connection);
        $schema->dropIfExists('users');
    }
};
```

Running migrations (SQLite example):

```php
<?php
require __DIR__.'/../vendor/autoload.php';

use Pairity\Database\ConnectionManager;
use Pairity\Migrations\Migrator;

$conn = ConnectionManager::make([
    'driver' => 'sqlite',
    'path'   => __DIR__ . '/../db.sqlite',
]);

$createUsers = require __DIR__ . '/migrations/CreateUsersTable.php';

$migrator = new Migrator($conn);
$migrator->setRegistry(['CreateUsersTable' => $createUsers]);

$applied = $migrator->migrate(['CreateUsersTable' => $createUsers]);
echo 'Applied: ' . json_encode($applied) . PHP_EOL;
```

Notes:
- The migrations runner tracks applied migrations in a `migrations` table with batches.
- For rollback, keep a registry of name => instance in the same process or use class names that can be autoloaded.
- SQLite has limitations around `ALTER TABLE` operations; this MVP emits native `ALTER TABLE` for supported versions (ADD COLUMN always; RENAME/DROP COLUMN require modern SQLite). For legacy versions, operations may fail; rebuild strategies can be added later.
  - Pairity includes a best-effort table rebuild fallback for legacy SQLite: when `DROP COLUMN`/`RENAME COLUMN` is unsupported, it recreates the table and copies data. Complex constraints/triggers may not be preserved.

### CLI

Pairity ships a tiny CLI for migrations. After `composer install`, the binary is available as `vendor/bin/pairity` or as a project bin if installed as a dependency.

Usage:

```
pairity migrate [--path=DIR] [--config=FILE]
pairity rollback [--steps=N] [--config=FILE]
pairity status [--path=DIR] [--config=FILE]
pairity reset [--config=FILE]
pairity make:migration Name [--path=DIR]
```

Options and environment:

- If `--config=FILE` is provided, it must be a PHP file returning the ConnectionManager config array.
- Otherwise, the CLI reads environment variables:
  - `DB_DRIVER` (mysql|mariadb|pgsql|postgres|postgresql|sqlite|sqlsrv)
  - `DB_HOST`, `DB_PORT`, `DB_DATABASE`, `DB_USERNAME`, `DB_PASSWORD`, `DB_CHARSET` (MySQL)
  - `DB_PATH` (SQLite path)
- If nothing is provided, defaults to a SQLite file at `db.sqlite` in project root.

Migration discovery:
- The CLI looks for migrations in `./database/migrations`, then `project/database/migrations`, then `examples/migrations`.
- Each PHP file should `return` a `MigrationInterface` instance (see examples). Files are applied in filename order.

Example ALTER migration (users add bio):

```php
return new class implements MigrationInterface {
    public function up(ConnectionInterface $connection): void
    {
        $schema = SchemaManager::forConnection($connection);
        $schema->table('users', function (Blueprint $t) {
            $t->string('bio', 500)->nullable();
            $t->index(['status'], 'users_status_index');
        });
    }
    public function down(ConnectionInterface $connection): void
    {
        $schema = SchemaManager::forConnection($connection);
        $schema->table('users', function (Blueprint $t) {
            $t->dropIndex('users_status_index');
            $t->dropColumn('bio');
        });
    }
};
```

Notes:
- Schema is optional; if omitted, DAOs behave as before (no casting, no timestamps/soft deletes).
- Timestamps use UTC and the format `Y-m-d H:i:s` for portability.
- Default `SELECT` is `*`. To limit columns, use `fields()`; it always takes precedence.

## DTO toArray (deep vs shallow)

DTOs implement `toArray(bool $deep = true)`.

- When `$deep` is true (default): the DTO is converted to an array and any related DTOs (including arrays of DTOs) are recursively converted.
- When `$deep` is false: only the top-level attributes are converted; related DTOs remain as objects.

Example:

```php
$users = (new UserDao($conn))
    ->with(['posts'])
    ->findAllBy(['status' => 'active']);

$deep    = array_map(fn($u) => $u->toArray(), $users);       // deep (default)
$shallow = array_map(fn($u) => $u->toArray(false), $users);  // shallow
```

## Roadmap

- Relations enhancements:
  - Nested eager loading (e.g., `posts.comments`)
  - `belongsToMany` (pivot tables)
  - Optional join‑based eager loading strategy
- Unit of Work & Identity Map
- Schema builder: broader ALTER coverage and more dialect nuances; better SQLite rebuild for complex constraints
- CLI: additional commands and quality‑of‑life improvements
- Testing matrix and examples for more drivers
- Caching layer and query logging hooks
- Production NoSQL adapters (MongoDB driver integration)