<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;

/**
 * Unit tests for WPDO_Points_Manager.
 *
 * Uses a custom $wpdb mock that tracks which SQL verbs were executed
 * (BEGIN/START TRANSACTION, COMMIT, ROLLBACK) so we can verify
 * transaction discipline without hitting a real database.
 */
class PointsManagerTest extends TestCase {

	/** @var object Original $wpdb mock from bootstrap. */
	private object $original_wpdb;

	protected function setUp(): void {
		if ( ! class_exists( 'WPDO_Points_Manager' ) ) {
			require_once WPDO_PLUGIN_DIR . 'includes/integrations/class-tmdo-points-manager.php';
		}

		global $wpdb;
		$this->original_wpdb = $wpdb;

		// Install a controllable mock that also has insert_id.
		$wpdb = $this->make_wpdb_mock();
	}

	protected function tearDown(): void {
		global $wpdb;
		$wpdb = $this->original_wpdb;
	}

	// ── credit() input validation ────────────────────────────────────────────

	public function test_credit_rejects_zero_delta(): void {
		$result = WPDO_Points_Manager::credit( 1, 0 );

		$this->assertFalse( $result['ok'] );
		$this->assertSame( 'credit delta must be positive', $result['error'] );
	}

	public function test_credit_rejects_negative_delta(): void {
		$result = WPDO_Points_Manager::credit( 1, -50 );

		$this->assertFalse( $result['ok'] );
		$this->assertSame( 'credit delta must be positive', $result['error'] );
	}

	// ── debit() input validation ─────────────────────────────────────────────

	public function test_debit_rejects_zero_delta(): void {
		$result = WPDO_Points_Manager::debit( 1, 0 );

		$this->assertFalse( $result['ok'] );
		$this->assertSame( 'debit delta must be positive', $result['error'] );
	}

	public function test_debit_rejects_negative_delta(): void {
		$result = WPDO_Points_Manager::debit( 1, -10 );

		$this->assertFalse( $result['ok'] );
		$this->assertSame( 'debit delta must be positive', $result['error'] );
	}

	// ── debit() insufficient balance ─────────────────────────────────────────

	public function test_debit_fails_when_balance_zero_and_no_overdraft(): void {
		// $wpdb->get_var returns null → balance = 0; debit 50 → new_balance = -50 → reject.
		$result = WPDO_Points_Manager::debit( 42, 50, 'purchase' );

		$this->assertFalse( $result['ok'] );
		$this->assertSame( 'insufficient_balance', $result['error'] );
	}

	public function test_debit_rollback_called_on_insufficient_balance(): void {
		global $wpdb;

		WPDO_Points_Manager::debit( 42, 50 );

		$sql_log = $wpdb->queries;
		// Expect BEGIN and ROLLBACK but NOT COMMIT.
		$this->assertContains( 'START TRANSACTION', $sql_log );
		$this->assertContains( 'ROLLBACK', $sql_log );
		$this->assertNotContains( 'COMMIT', $sql_log );
	}

	// ── debit() allow_overdraft ───────────────────────────────────────────────

	public function test_debit_with_allow_overdraft_succeeds_below_zero(): void {
		$result = WPDO_Points_Manager::debit( 1, 100, 'force', 0, '', true );

		$this->assertTrue( $result['ok'] );
		$this->assertSame( -100, $result['balance'] );
	}

	// ── credit() happy path ───────────────────────────────────────────────────

	public function test_credit_returns_ok_and_new_balance(): void {
		$result = WPDO_Points_Manager::credit( 7, 200, 'signup_bonus' );

		$this->assertTrue( $result['ok'] );
		$this->assertSame( 200, $result['balance'] );
		$this->assertArrayHasKey( 'ledger_id', $result );
	}

	public function test_credit_records_begin_and_commit(): void {
		global $wpdb;

		WPDO_Points_Manager::credit( 7, 100, 'test' );

		$sql_log = $wpdb->queries;
		$this->assertContains( 'START TRANSACTION', $sql_log );
		$this->assertContains( 'COMMIT', $sql_log );
		$this->assertNotContains( 'ROLLBACK', $sql_log );
	}

	public function test_credit_truncates_long_reason(): void {
		// Reasons over 60 chars must be silently truncated (not cause DB error).
		$long_reason = str_repeat( 'x', 100 );
		$result      = WPDO_Points_Manager::credit( 5, 10, $long_reason );

		$this->assertTrue( $result['ok'] );
	}

	// ── get_balance() ─────────────────────────────────────────────────────────

	public function test_get_balance_returns_zero_for_unknown_user(): void {
		// Mock $wpdb->get_var returns null → (int) null = 0.
		$balance = WPDO_Points_Manager::get_balance( 9999 );

		$this->assertSame( 0, $balance );
	}

	// ── get_ledger() ─────────────────────────────────────────────────────────

	public function test_get_ledger_returns_empty_array_when_no_rows(): void {
		$ledger = WPDO_Points_Manager::get_ledger( 9999 );

		$this->assertSame( array(), $ledger );
	}

	public function test_get_ledger_clamps_limit_between_1_and_500(): void {
		// Just confirm no exception on extreme inputs.
		WPDO_Points_Manager::get_ledger( 1, -5 );
		WPDO_Points_Manager::get_ledger( 1, 9999 );
		$this->assertTrue( true );
	}

	// ── helper ───────────────────────────────────────────────────────────────

	/**
	 * Build a $wpdb mock that:
	 *  - Records every SQL statement to ->queries[]
	 *  - Returns null for SELECT…FOR UPDATE (simulating empty DB / no row)
	 *  - After a successful UPSERT, returns the inserted delta for re-read SELECTs
	 *  - Returns empty array for get_results
	 *  - Returns 1 for query/insert
	 *  - Has insert_id = 99
	 */
	private function make_wpdb_mock(): object {
		return new class {
			public string  $prefix               = 'wp_';
			public string  $postmeta             = 'wp_postmeta';
			public string  $posts                = 'wp_posts';
			public string  $options              = 'wp_options';
			public string  $usermeta             = 'wp_usermeta';
			public string  $users                = 'wp_users';
			public array   $queries              = array();
			public int     $insert_id            = 99;
			public string  $last_error           = '';
			public ?int    $last_upserted_balance = null;

			public function prepare( string $sql, ...$args ): string {
				$i = 0;
				return preg_replace_callback( '/%[sd]/', function () use ( &$i, $args ) {
					return $args[ $i++ ] ?? '?';
				}, $sql );
			}

			public function get_var( string $sql ): ?string {
				$this->queries[] = $sql;
				// SELECT … FOR UPDATE simulates an empty membership table (no row).
				if ( false !== strpos( $sql, 'FOR UPDATE' ) ) {
					return null;
				}
				// Post-UPSERT re-read returns the balance written by the last INSERT.
				if ( null !== $this->last_upserted_balance ) {
					return (string) $this->last_upserted_balance;
				}
				return null;
			}

			public function get_results( string $sql, $output = 'OBJECT' ): array {
				$this->queries[] = $sql;
				return array();
			}

			public function query( string $sql ): int {
				$this->queries[] = $sql;
				// Capture the delta from INSERT…VALUES(user_id, delta) so subsequent
				// re-read SELECTs can return a meaningful balance (mirrors real DB).
				if ( preg_match( '/VALUES\s*\(\s*\d+\s*,\s*(-?\d+)\s*\)/', $sql, $m ) ) {
					$this->last_upserted_balance = (int) $m[1];
				}
				return 1;
			}

			public function insert( string $table, array $data, $format = null ): int {
				$this->queries[] = "INSERT {$table}";
				return 1;
			}

			public function update( string $table, array $data, array $where, $format = null, $where_format = null ): int {
				$this->queries[] = "UPDATE {$table}";
				return 1;
			}

			public function delete( string $table, array $where, $format = null ): int {
				$this->queries[] = "DELETE {$table}";
				return 1;
			}

			public function replace( string $table, array $data, $format = null ): int {
				$this->queries[] = "REPLACE {$table}";
				return 1;
			}
		};
	}
}