<?php
declare(strict_types=1);

use PHPUnit\Framework\TestCase;

/**
 * Integration test for WPDO_Installer::install_v2_tables() — PR-2 v2.0.0 schema.
 *
 * Verifies idempotent table creation for:
 *   - wp_*_wpdo_audit
 *   - wp_*_wpdo_shadow_diffs
 *   - wp_*_wpdo_site_metrics
 *   - wp_*_wpdo_uni_options
 *
 * @covers WPDO_Installer::install_v2_tables
 * @covers WPDO_Installer::v2_tables_status
 */
class InstallerV2Test extends TestCase {

	public static function setUpBeforeClass(): void {
		// Drop v2 tables for a clean slate.
		global $wpdb;
		$p = $wpdb->prefix;
		$wpdb->query( "DROP TABLE IF EXISTS `{$p}wpdo_audit`" );
		$wpdb->query( "DROP TABLE IF EXISTS `{$p}wpdo_shadow_diffs`" );
		$wpdb->query( "DROP TABLE IF EXISTS `{$p}wpdo_site_metrics`" );
		$wpdb->query( "DROP TABLE IF EXISTS `{$p}wpdo_uni_options`" );
	}

	public function test_v2_tables_initially_absent(): void {
		$status = WPDO_Installer::v2_tables_status();
		foreach ( $status as $table => $exists ) {
			$this->assertFalse( $exists, "Expected {$table} to NOT exist initially" );
		}
	}

	public function test_install_v2_tables_creates_all_four(): void {
		WPDO_Installer::install_v2_tables();

		$status = WPDO_Installer::v2_tables_status();
		foreach ( $status as $table => $exists ) {
			$this->assertTrue( $exists, "Expected {$table} to exist after install_v2_tables()" );
		}
	}

	public function test_install_v2_tables_is_idempotent(): void {
		WPDO_Installer::install_v2_tables();
		WPDO_Installer::install_v2_tables(); // Second call must not error.
		WPDO_Installer::install_v2_tables(); // Third for good measure.

		$status = WPDO_Installer::v2_tables_status();
		$this->assertCount( 4, $status );
		$this->assertTrue( array_reduce( $status, static fn( $carry, $v ) => $carry && $v, true ) );
	}

	public function test_audit_table_has_required_columns(): void {
		global $wpdb;
		$p   = $wpdb->prefix;
		$cols = $wpdb->get_col( "SHOW COLUMNS FROM `{$p}wpdo_audit`" );

		// PR-2 spec: op, value_before, value_after, source, trace_id are required.
		foreach ( array( 'op', 'value_before', 'value_after', 'source', 'trace_id' ) as $required ) {
			$this->assertContains( $required, $cols, "wpdo_audit missing column {$required}" );
		}
	}

	public function test_shadow_diffs_table_has_required_columns(): void {
		global $wpdb;
		$p   = $wpdb->prefix;
		$cols = $wpdb->get_col( "SHOW COLUMNS FROM `{$p}wpdo_shadow_diffs`" );

		foreach ( array( 'entity_type', 'entity_id', 'meta_key', 'postmeta_value', 'zone_value', 'diff_hash' ) as $required ) {
			$this->assertContains( $required, $cols, "wpdo_shadow_diffs missing column {$required}" );
		}
	}

	public function test_uni_options_has_unique_index_on_option_name(): void {
		global $wpdb;
		$p       = $wpdb->prefix;
		$indexes = $wpdb->get_results(
			$wpdb->prepare(
				'SELECT INDEX_NAME, COLUMN_NAME, NON_UNIQUE FROM information_schema.STATISTICS WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = %s',
				$p . 'wpdo_uni_options'
			),
			ARRAY_A
		);

		$found_unique = false;
		foreach ( $indexes as $idx ) {
			if ( 'option_name' === $idx['COLUMN_NAME'] && '0' === (string) $idx['NON_UNIQUE'] ) {
				$found_unique = true;
				break;
			}
		}
		$this->assertTrue( $found_unique, 'Expected UNIQUE index on wpdo_uni_options.option_name' );
	}

	public function test_audit_table_indexes_for_query_performance(): void {
		global $wpdb;
		$p       = $wpdb->prefix;
		$indexes = $wpdb->get_col(
			$wpdb->prepare(
				'SELECT DISTINCT INDEX_NAME FROM information_schema.STATISTICS WHERE TABLE_SCHEMA = DATABASE() AND TABLE_NAME = %s',
				$p . 'wpdo_audit'
			)
		);

		// Performance-critical indexes per Part F.3 schema spec.
		foreach ( array( 'idx_entity', 'idx_meta_key', 'idx_ts', 'idx_trace' ) as $required ) {
			$this->assertContains( $required, $indexes, "wpdo_audit missing index {$required}" );
		}
	}

	public static function tearDownAfterClass(): void {
		// Leave v2 tables in place for subsequent tests / dev convenience.
		// Cleanup happens via wp wpdo cleanup-uae-tables --confirm in real upgrades.
	}
}