<?php

if (!defined('ABSPATH')) {
    exit;
}

/**
 * Lowercase-rename maintenance operation for plugin tables.
 *
 * Owns making all plugin table names lowercase (for hosts running with
 * lower_case_table_names=0), and detecting/adopting orphaned plugin tables
 * left under old prefixes (from site migrations or the rename bug in
 * v2.35.16 through v3.x). This is a prefix-based, tenant-isolation-aware
 * flow: on multisite, a sibling subsite owns and lowercases its own tables,
 * so a table under a DIFFERENT active blog's prefix is left alone; a
 * genuinely orphaned prefix (no live blog) is renamed and handed to the
 * orphan-adoption collaborator to recover.
 *
 * Extracted from the table-bootstrap orchestrator (DatabaseUpgradeBootstrap)
 * because table-bootstrap orchestration and the lowercase-rename maintenance
 * operation are distinct concerns: this one runs unconditionally on every
 * createDatabaseTables() pass, has its own MySQL-variable-driven skip path,
 * and reaches into information_schema directly rather than the plugin's own
 * tables.
 *
 * Collaborator of ABJ_404_Solution_DatabaseUpgradeBootstrap, which constructs
 * it fresh on every call (never cached) with the upgrade coordinator, the
 * current DB core / logger, and a pre-computed active-blog-prefix set, so it
 * always observes whichever dependencies are current at call time (dbCore /
 * logger can be swapped at runtime via replaceDatabaseUpgradeDependencies()
 * on the owning component).
 */
class ABJ_404_Solution_DatabaseTableLowercaseRenamer {

    /** @var ABJ_404_Solution_DatabaseUpgradeCoordinator */
    private $coordinator;

    /** @var ABJ_404_Solution_DatabaseCore */
    private $dbCore;

    /** @var ABJ_404_Solution_Logging */
    private $logger;

    /** @var array<int, string> */
    private $activeBlogPrefixesLowercase;

    /**
     * @param ABJ_404_Solution_DatabaseUpgradeCoordinator $coordinator
     * @param ABJ_404_Solution_DatabaseCore $dbCore Deliberately untyped at the
     *   PHP level (matching ABJ_404_Solution_DatabaseUpgradeComponent::$dbCore):
     *   this collaborator needs methods from both DatabaseCoreInterface
     *   (tableNameResolver) and DatabaseQueryInterface (queryAndGetResults),
     *   and PHP 7.4 (the plugin's floor version) has no intersection types.
     *   Test doubles (e.g. Abj404NullDatabaseCore) implement those interfaces
     *   without extending the concrete class, so a native type hint here would
     *   break them.
     * @param ABJ_404_Solution_Logging $logger
     * @param array<int, string> $activeBlogPrefixesLowercase Lowercased table
     *   prefixes of every active site on the network (or just the current
     *   prefix on single-site), computed once by the caller before
     *   construction since it's a pure read with no per-call state.
     */
    public function __construct(ABJ_404_Solution_DatabaseUpgradeCoordinator $coordinator,
            $dbCore, ABJ_404_Solution_Logging $logger,
            array $activeBlogPrefixesLowercase) {
        $this->coordinator = $coordinator;
        $this->dbCore = $dbCore;
        $this->logger = $logger;
        $this->activeBlogPrefixesLowercase = $activeBlogPrefixesLowercase;
    }

    /** Makes all plugin table names lowercase, in case someone thought it was funny to use
     * the lower_case_table_names=0 setting. Also detects and adopts orphaned plugin tables
     * under old prefixes (from site migrations or the rename bug in v2.35.16 through v3.x).
     * @return void
     */
    public function rename() {
        global $wpdb;

        // On case-insensitive MySQL (lower_case_table_names >= 1), table names
        // are already treated as lowercase internally. Renaming is pointless and
        // can cause issues on some hosting setups.
        // DAO-bypass-approved: Schema-bootstrap inside renameAbj404TablesToLowerCase(). Runs before plugin DAO is fully wired during DB upgrades.
        $lctnResult = $wpdb->get_row("SHOW VARIABLES LIKE 'lower_case_table_names'", ARRAY_A);
        if (is_array($lctnResult)) {
            $lctnValue = null;
            foreach ($lctnResult as $key => $value) {
                if (strtolower((string)$key) === 'value') {
                    $lctnValue = $value;
                    break;
                }
            }
            if (is_scalar($lctnValue) && (int)$lctnValue >= 1) {
                // MySQL already handles table names case-insensitively.
                // Still run adoption check in case of prefix mismatch.
                $this->coordinator->orphanAdoptionUpgrade()->adoptOrphanedTables();
                return;
            }
        }

        // Fetch all tables containing "abj404", case-insensitive
        $dbNameRaw = $wpdb->dbname ?? '';
        if ($dbNameRaw === '') {
            $this->logger->warn("Could not determine database name for lowercase rename.");
            return;
        }
        $dbNameEscaped = esc_sql($dbNameRaw);
        $dbName = is_array($dbNameEscaped) ? '' : $dbNameEscaped;
        $query = "SELECT table_name
            FROM information_schema.tables
            WHERE table_schema = '{$dbName}'
            AND LOWER(table_name) LIKE '%abj404%'";
        $results = $this->dbCore->queryAndGetResults($query);

        if (!is_array($results['rows'])) {
            $this->logger->warn("Could not query information_schema tables for lowercase rename.");
            return;
        }

        // Tenant isolation: a sibling subsite owns and lowercases its own
        // tables. Never rename tables that belong to a DIFFERENT active
        // multisite blog (same whole-schema-scan class as the orphan-adoption
        // finding). A migrated old prefix with no live blog is absent from the
        // active-blog set and is still renamed so adoption can recover it.
        $currentPrefix = $this->dbCore->tableNameResolver()->getLowercasePrefix();
        $activeBlogPrefixes = $this->activeBlogPrefixesLowercase;

        foreach ($results['rows'] as $row) {
            if (!is_array($row)) {
                continue;
            }
            // Case-insensitive key lookup: MySQL drivers return information_schema
            // column names in varying cases (table_name, TABLE_NAME, Table_Name).
            $tableName = null;
            foreach ($row as $key => $value) {
                    if (strtolower((string)$key) === 'table_name' && is_scalar($value)) {
                        $tableName = (string)$value;
                    break;
                }
            }

            if (!empty($tableName)) {
                $lowercaseName = strtolower($tableName);

                // Check if the table name is already lowercase, skip if it is
                if ($tableName !== $lowercaseName) {
                    $tablePrefix = $this->prefixOfAbj404Table($lowercaseName);
                    if ($tablePrefix !== null && $tablePrefix !== $currentPrefix
                            && in_array($tablePrefix, $activeBlogPrefixes, true)) {
                        // Belongs to a different active subsite. Leave it alone.
                        continue;
                    }
                    // Rename the table to lowercase
                    $renameQuery = "RENAME TABLE `{$tableName}` TO `{$lowercaseName}`";
                    $this->dbCore->queryAndGetResults($renameQuery,
                        ['ignore_errors' => ["already exists"]]);
                    $this->logger->infoMessage("Renamed table {$tableName} to {$lowercaseName}\n");
                }
            } else {
                $this->logger->warn("I didn't find a table name in the results of this row: " .
                    print_r($row, true));
            }
        }

        // After renaming, check for orphaned tables under old prefixes.
        $this->coordinator->orphanAdoptionUpgrade()->adoptOrphanedTables();
    }

    /**
     * Extract the table prefix from a lowercase plugin table name: everything
     * before the first "abj404" segment (e.g. "wp_2_abj404_redirects" -> "wp_2_").
     * Returns null when the name has no abj404 segment.
     *
     * @param string $lowercaseTableName
     * @return string|null
     */
    private function prefixOfAbj404Table(string $lowercaseTableName): ?string {
        $pos = strpos($lowercaseTableName, 'abj404');
        if ($pos === false) {
            return null;
        }
        $prefix = substr($lowercaseTableName, 0, $pos);
        return is_string($prefix) ? $prefix : null;
    }
}