<?php

$webroot = dirname(__DIR__, 2);
include_once "{$webroot}/include/boot.php";
include_once "{$webroot}/include/log_functions.php";
command_line_only();
set_time_limit(0);
logScript(sprintf('Started script - %s', __FILE__));

$help_text = <<<'HELP'
NAME
    purge_duplicates - remove duplicate resources.

SYNOPSIS
    php /path/to/pages/tools/purge_duplicates.php [OPTIONS]

DESCRIPTION
    A tool to help administrators remove duplicate resources faster. If desired, duplicates can be fully deleted from 
    the system.

OPTIONS SUMMARY

    -h, --help              Display this help text and exit.
    --dry-run               Perform a trial run with no changes made.
    --manage-method         Determines how the script will deal with the duplicates removal. Default: LIFO.
                            Available options are:-
                                * FIFO (First In, First Out) - will remove old resources and keep the last one found
                                * LIFO (Last In, First Out) - will remove new duplicate resources and keep the first one found
    --delete-permanently    Delete duplicate resources permanently. Default off - resources move to the configured resource_deletion_state
    -c, --collection        Collection ID to limit the duplicates removal within a range (ie resources in the specified
                            collection). You don't need to have all duplicates in the collection, just one of them will 
                            be enough. Allowed multiple instances.

EXAMPLES
    # Testing script - always use dry-run to avoid silly mistakes (e.g typos)
    php purge_duplicates.php --dry-run

    # To remove all duplicates in the system (dropping the most recent duplicates)
    php purge_duplicates.php
    php purge_duplicates.php --manage-method=LIFO

    # To remove all duplicates in the system (keeping the most recent duplicates)
    php purge_duplicates.php --manage-method=FIFO

    # To remove duplicates (keeping the most recent) in the system but only within a selected subset
    php purge_duplicates.php --manage-method=FIFO --collection=50
    php purge_duplicates.php --manage-method=FIFO -c=50 -c=100 -c=200

HELP;

// Script options @see https://www.php.net/manual/en/function.getopt.php
$cli_short_options = 'hc:';
$cli_long_options  = array(
    'help',
    'dry-run',
    'manage-method:',
    'delete-permanently',
    'collection:'
);

// Defaults
$dry_run = false;
$dry_run_text = "";
$manage_method = 'LIFO';
$manage_method_text = 'Keep earliest resource found and remove later duplicates';
$order_by = 'ASC'; # depends on the $manage_method value
$delete_permanently = false;
$collections = [];

// Option logging
$logScriptTexts = [];

foreach (getopt($cli_short_options, $cli_long_options) as $option_name => $option_value) {
    if (in_array($option_name, ['h', 'help'])) {
        ob_clean();
        echo $help_text;
        exit(0);
    } elseif ($option_name == 'dry-run') {
        $dry_run = true;
        $dry_run_text = strtoupper($option_name) . " ";
        $logScriptTexts[] = "Script running";
    } elseif ($option_name == 'delete-permanently') {
        $delete_permanently = true;
        $logScriptTexts[] = "Script running with '{$option_name}' option enabled";
    } elseif ($option_name == 'manage-method' && is_string($option_value)) {
        $manage_method = $option_value;
        if ($manage_method == 'FIFO') {
            $manage_method_text = 'Keep latest resource found and remove earlier duplicates';
            $order_by = 'DESC';
        }
    } elseif (in_array($option_name, ['c', 'collection'])) {
        $collections = array_values(array_filter(is_array($option_value) ? $option_value : [$option_value], 'is_int_loose'));
        $logScriptTexts[] = "Script running for following collections: " . implode(', ', $collections);
    }
}

// Reject invalid parameters and combinations
if ($dry_run && $delete_permanently) {
    logScript("ERROR: Script terminated; options --dry-run and --delete-permanently are mutually exclusive");
    exit(0);
}

if (!in_array($manage_method, array('FIFO', 'LIFO'))) {
    logScript("ERROR: Script terminated; option --manage-method={$manage_method} is invalid");
    exit(0);
}

$logScriptTexts[] = "Script running with the '{$manage_method}' method; " . $manage_method_text;

// Log the options in effect for this run
foreach ($logScriptTexts as $logScriptText) {
    logScript($dry_run_text . $logScriptText);
}

// Identify the duplicates depending on the presence or otherwise of passed-in collections
if (empty($collections)) {
    // All duplicates
    $duplicates_by_checksum =
    ps_query("SELECT r1.file_checksum, r1.ref 
        FROM resource r1
        WHERE coalesce(r1.file_checksum, '') <> ''
        AND ( SELECT count(*) r2count from resource r2 WHERE r2.file_checksum = r1.file_checksum ) > 1
        ORDER BY r1.file_checksum ASC, r1.ref {$order_by}");
} else {
    // Duplicates where the checksum is present in any of the passed-in collections
    $duplicates_by_checksum =
    ps_query("SELECT d1.file_checksum, d1.ref FROM (
        SELECT r1.file_checksum, r1.ref FROM resource r1
            WHERE coalesce(r1.file_checksum, '') <> ''
            AND ( SELECT count(*) r2count from resource r2 WHERE r2.file_checksum = r1.file_checksum ) > 1
            ORDER BY r1.file_checksum ASC, r1.ref ASC) as d1
        WHERE d1.file_checksum IN
            (SELECT r3.file_checksum from collection_resource cr
            INNER JOIN resource r3 on r3.ref = cr.resource and coalesce(r3.file_checksum,'') <> ''
            WHERE cr.collection IN (" . ps_param_insert(count($collections)) . ")) 
            ORDER BY d1.file_checksum ASC, d1.ref {$order_by}", ps_param_fill($collections, 'i'));
}

$count_matching_checksums = count($duplicates_by_checksum);
$count_permanent_deletions = 0;
$count_marked_deletions = 0;
$count_unchanged = 0;

logScript($dry_run_text . "STARTING SUMMARY");
logscript($dry_run_text . "STARTING Count of candidate resources with matching checksums is {$count_matching_checksums}");
logScript($dry_run_text . "RESOURCE DETAILS");

$keep_resources = array();
$delete_resources = array();
$last_kept_resource = null;
$last_checksum = null;
// Build an array of resources which will be kept, and another array of the resources to be deleted
foreach ($duplicates_by_checksum as $duplicate) {
    if ($duplicate["file_checksum"] !== $last_checksum) {
        // The first resource for each new checksum will be kept
        $keep_resources[$duplicate["ref"]] = $duplicate["file_checksum"];
        $last_checksum = $duplicate["file_checksum"];
        $last_kept_resource = $duplicate["ref"];
    } else {
        // Subsequent resources for this checksum will be deleted
        $delete_resources[$last_kept_resource][] = $duplicate["ref"];
    }
}
// The kept resources array is currently in checksum sequence
// We want to process the resources in ascending kept resource sequence for logging readability
ksort($keep_resources);

// Process and log each kept resource and checksum, deleting the other resources identified earlier (ie. with the same checksum))
foreach ($keep_resources as $keep_ref => $keep_checksum) {
    // Log resource which will be kept
    logScript($dry_run_text . "Keep resource #{$keep_ref} with checksum '{$keep_checksum}'");
    $count_unchanged += 1;

    // Resource deletion
    foreach ($delete_resources[$keep_ref] as $delete_resource) {
        if ($delete_permanently) {
            // Option delete-permanently and dry-run are mutually exclusive
            // Option dry-run will never be true and the associated text is always blank at this point; this is just a belt and braces check
            logScript($dry_run_text . ".. Deleting resource #{$delete_resource} with checksum '{$keep_checksum}' permanently");
            $count_permanent_deletions += 1;
            if (!$dry_run) {
                unset($resource_deletion_state);
                delete_resource($delete_resource);
            }
        } else {
            logScript($dry_run_text . ".. Deleting resource #{$delete_resource} with checksum '{$keep_checksum}' logically; marked as '{$resource_deletion_state}'");
            $count_marked_deletions += 1;
            if (!$dry_run) {
                update_archive_status($delete_resource, $resource_deletion_state);
            }
        }
    }
}

// Report various processing counts
logScript($dry_run_text . "ENDING SUMMARY");
$count_processed_resources = 0;
logscript($dry_run_text . "ENDING Count of resources which are kept ............... {$count_unchanged}");

if ($delete_permanently) {
    logscript($dry_run_text . "ENDING Count of resources permanently deleted .......... {$count_permanent_deletions}");
    $count_processed_resources = $count_unchanged + $count_permanent_deletions;
} else {
    logscript($dry_run_text . "ENDING Count of resources marked as deleted ............ {$count_marked_deletions}");
    $count_processed_resources = $count_unchanged + $count_marked_deletions;
}

// Report whether or not ending counts are as expected
if ($count_matching_checksums == $count_processed_resources) {
    logScript($dry_run_text . "ENDING Count of processed resources with matching checksums is {$count_processed_resources} as expected");
} else {
    logScript($dry_run_text . "WARNING Count of processed resources with matching checksums is {$count_processed_resources} which is unexpected");
}
logScript($dry_run_text . "Script completed!");