<?php
/**
 * admin2/api/cleanup.php — Event Cleanup: Preview & Execute.
 *
 * GET  — Preview a cleanup query (count + size estimate, no delete).
 * POST — Execute a cleanup query (dry_run=true for preview, false for delete).
 */
require_once __DIR__ . '/../lib/helpers.php';

$pdo = db();
$method = $_SERVER['REQUEST_METHOD'];

// ── Shared filter builder ──────────────────────────────────────────────
// Returns [sql_conditions[], params[]] for the WHERE clauses.
function build_filters(array $opts): array {
    $conds = [];
    $params = [];

    // Kinds filter
    if (!empty($opts['kinds'])) {
        $kinds = is_array($opts['kinds']) ? $opts['kinds'] : explode(',', $opts['kinds']);
        $kinds = array_map('intval', $kinds);
        $kinds = array_filter($kinds, fn($v) => $v > 0);
        if (!empty($kinds)) {
            $placeholders = [];
            foreach ($kinds as $i => $k) {
                $key = ':kind_' . $i;
                $placeholders[] = $key;
                $params[$key] = $k;
            }
            $conds[] = 'e.kind IN (' . implode(',', $placeholders) . ')';
        }
    }

    // Date/time range filter (supports YYYY-MM-DD or YYYY-MM-DD HH:MM)
    $from_date = $opts['from_date'] ?? '';
    $to_date = $opts['to_date'] ?? '';
    if ($from_date !== '') {
        if (preg_match('/^\d{4}-\d{2}-\d{2}$/', $from_date)) {
            $conds[] = 'e.created_at >= EXTRACT(EPOCH FROM :from_date::date)::BIGINT';
            $params[':from_date'] = $from_date;
        } elseif (preg_match('/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}$/', $from_date)) {
            $conds[] = 'e.created_at >= EXTRACT(EPOCH FROM :from_date::timestamp)::BIGINT';
            $params[':from_date'] = $from_date . ':00';
        }
    }
    if ($to_date !== '') {
        if (preg_match('/^\d{4}-\d{2}-\d{2}$/', $to_date)) {
            $conds[] = 'e.created_at < (EXTRACT(EPOCH FROM :to_date::date)::BIGINT + 86400)';
            $params[':to_date'] = $to_date;
        } elseif (preg_match('/^\d{4}-\d{2}-\d{2} \d{2}:\d{2}$/', $to_date)) {
            $conds[] = 'e.created_at < EXTRACT(EPOCH FROM :to_date::timestamp)::BIGINT';
            $params[':to_date'] = $to_date . ':00';
        }
    }

    // Follows filter
    $follows_filter = $opts['follows_filter'] ?? 'all';
    if ($follows_filter === 'follows') {
        $conds[] = 'e.pubkey IN (SELECT pubkey FROM caching_followed_pubkeys)';
    } elseif ($follows_filter === 'non_follows') {
        $conds[] = 'e.pubkey NOT IN (SELECT pubkey FROM caching_followed_pubkeys)';
    }

    return [$conds, $params];
}

// ── Build a WHERE clause string from conditions ────────────────────────
function where_clause(array $conds): string {
    if (empty($conds)) return '';
    return 'AND ' . implode("\n  AND ", $conds);
}

// ── Format bytes as human-readable ─────────────────────────────────────
function format_bytes(int $bytes): string {
    if ($bytes < 1024) return $bytes . ' B';
    if ($bytes < 1048576) return round($bytes / 1024, 1) . ' KB';
    if ($bytes < 1073741824) return round($bytes / 1048576, 1) . ' MB';
    return round($bytes / 1073741824, 2) . ' GB';
}

// ── GET: Preview ───────────────────────────────────────────────────────
if ($method === 'GET') {
    $opts = [
        'follows_filter' => $_GET['follows_filter'] ?? 'all',
        'kinds'          => $_GET['kinds'] ?? '',
        'from_date'      => $_GET['from_date'] ?? '',
        'to_date'        => $_GET['to_date'] ?? '',
        'max_events'     => intval($_GET['max_events'] ?? 0),
    ];

    list($conds, $params) = build_filters($opts);
    $where = where_clause($conds);

    // Preview SQL (for display)
    $sql_preview = "SELECT COUNT(*) AS match_count,\n"
        . "       COALESCE(SUM(pg_column_size(event_json)), 0) AS total_size_bytes\n"
        . "FROM events e\n"
        . "WHERE 1=1\n"
        . ($where ? "  $where\n" : '');

    // Count + size query
    $count_sql = "SELECT COUNT(*) AS match_count,\n"
        . "       COALESCE(SUM(pg_column_size(event_json)), 0) AS total_size_bytes\n"
        . "FROM events e\n"
        . "WHERE 1=1 $where";

    try {
        $stmt = $pdo->prepare($count_sql);
        $stmt->execute($params);
        $row = $stmt->fetch();
        $match_count = intval($row['match_count'] ?? 0);
        $total_size_bytes = intval($row['total_size_bytes'] ?? 0);
    } catch (PDOException $e) {
        json_response(['error' => 'Preview query failed: ' . $e->getMessage()]);
        exit;
    }

    // Kind breakdown
    $breakdown = [];
    if ($match_count > 0) {
        $breakdown_sql = "SELECT e.kind,\n"
            . "       COUNT(*) AS count,\n"
            . "       COALESCE(SUM(pg_column_size(e.event_json)), 0) AS size_bytes\n"
            . "FROM events e\n"
            . "WHERE 1=1 $where\n"
            . "GROUP BY e.kind\n"
            . "ORDER BY count DESC\n"
            . "LIMIT 50";
        try {
            $stmt = $pdo->prepare($breakdown_sql);
            $stmt->execute($params);
            $rows = $stmt->fetchAll();
            foreach ($rows as $r) {
                $breakdown[] = [
                    'kind'       => intval($r['kind']),
                    'count'      => intval($r['count']),
                    'size_bytes' => intval($r['size_bytes']),
                ];
            }
        } catch (PDOException $e) {
            // Breakdown is non-critical
        }
    }

    // If a query_id was provided, update last_preview_count and last_preview_size_bytes
    $query_id = intval($_GET['query_id'] ?? 0);
    if ($query_id > 0) {
        try {
            $pdo->prepare(
                "UPDATE cleanup_saved_queries\n"
                . "   SET last_preview_count = :count,\n"
                . "       last_preview_size_bytes = :size\n"
                . " WHERE id = :id"
            )->execute([
                ':id'    => $query_id,
                ':count' => $match_count,
                ':size'  => $total_size_bytes,
            ]);
        } catch (PDOException $e) {}
    }

    json_response([
        'match_count'       => $match_count,
        'total_size_bytes'  => $total_size_bytes,
        'total_size_human'  => format_bytes($total_size_bytes),
        'avg_size_per_event' => $match_count > 0 ? intval($total_size_bytes / $match_count) : 0,
        'kinds_breakdown'   => $breakdown,
        'sql_preview'       => $sql_preview,
    ]);
    exit;
}

// ── POST: Execute (or dry-run) ─────────────────────────────────────────
if ($method === 'POST') {
    $body = json_decode(file_get_contents('php://input'), true);
    if (!$body) {
        json_response(['error' => 'Invalid JSON body']);
        exit;
    }

    $dry_run = !empty($body['dry_run']);
    $opts = [
        'follows_filter' => $body['follows_filter'] ?? 'all',
        'kinds'          => $body['kinds'] ?? [],
        'from_date'      => $body['from_date'] ?? '',
        'to_date'        => $body['to_date'] ?? '',
        'max_events'     => intval($body['max_events'] ?? 0),
    ];

    list($conds, $params) = build_filters($opts);
    $where = where_clause($conds);

    // If dry_run, return preview (same as GET)
    if ($dry_run) {
        $count_sql = "SELECT COUNT(*) AS match_count,\n"
            . "       COALESCE(SUM(pg_column_size(event_json)), 0) AS total_size_bytes\n"
            . "FROM events e\n"
            . "WHERE 1=1 $where";
        try {
            $stmt = $pdo->prepare($count_sql);
            $stmt->execute($params);
            $row = $stmt->fetch();
            $match_count = intval($row['match_count'] ?? 0);
            $total_size_bytes = intval($row['total_size_bytes'] ?? 0);
        } catch (PDOException $e) {
            json_response(['error' => 'Preview query failed: ' . $e->getMessage()]);
            exit;
        }

        // Kind breakdown
        $breakdown = [];
        if ($match_count > 0) {
            $breakdown_sql = "SELECT e.kind, COUNT(*) AS count,\n"
                . "       COALESCE(SUM(pg_column_size(e.event_json)), 0) AS size_bytes\n"
                . "FROM events e\n"
                . "WHERE 1=1 $where\n"
                . "GROUP BY e.kind\n"
                . "ORDER BY count DESC\n"
                . "LIMIT 50";
            try {
                $stmt = $pdo->prepare($breakdown_sql);
                $stmt->execute($params);
                foreach ($stmt->fetchAll() as $r) {
                    $breakdown[] = [
                        'kind'       => intval($r['kind']),
                        'count'      => intval($r['count']),
                        'size_bytes' => intval($r['size_bytes']),
                    ];
                }
            } catch (PDOException $e) {}
        }

        json_response([
            'match_count'       => $match_count,
            'total_size_bytes'  => $total_size_bytes,
            'total_size_human'  => format_bytes($total_size_bytes),
            'avg_size_per_event' => $match_count > 0 ? intval($total_size_bytes / $match_count) : 0,
            'kinds_breakdown'   => $breakdown,
            'dry_run'           => true,
        ]);
        exit;
    }

    // ── Actual DELETE ──────────────────────────────────────────────────
    $max_events = intval($body['max_events'] ?? 0);
    $limit_clause = $max_events > 0 ? 'LIMIT :max_events' : '';

    // First, get the count and size of what will be deleted
    $preview_sql = "SELECT COUNT(*) AS match_count,\n"
        . "       COALESCE(SUM(pg_column_size(event_json)), 0) AS total_size_bytes\n"
        . "FROM events e\n"
        . "WHERE 1=1 $where";
    try {
        $stmt = $pdo->prepare($preview_sql);
        $stmt->execute($params);
        $row = $stmt->fetch();
        $expected_count = intval($row['match_count'] ?? 0);
        $expected_bytes = intval($row['total_size_bytes'] ?? 0);
    } catch (PDOException $e) {
        json_response(['error' => 'Pre-delete count failed: ' . $e->getMessage()]);
        exit;
    }

    // Build the DELETE using id IN (subquery) for safe LIMIT + ORDER BY
    $delete_sql = "DELETE FROM events e\n"
        . "WHERE e.id IN (\n"
        . "    SELECT e2.id FROM events e2\n"
        . "    WHERE 1=1 $where\n"
        . "    ORDER BY e2.created_at ASC\n"
        . "    $limit_clause\n"
        . ")";

    $start_time = microtime(true);
    try {
        $stmt = $pdo->prepare($delete_sql);
        if ($max_events > 0) {
            $params[':max_events'] = $max_events;
        }
        $stmt->execute($params);
        $deleted_count = $stmt->rowCount();
    } catch (PDOException $e) {
        json_response(['error' => 'Delete query failed: ' . $e->getMessage()]);
        exit;
    }
    $duration_ms = round((microtime(true) - $start_time) * 1000);

    // If we deleted fewer than expected, the actual freed bytes are proportional
    $freed_bytes = $expected_count > 0
        ? intval($expected_bytes * ($deleted_count / $expected_count))
        : 0;

    // Clear stats cache so the dashboard reflects changes immediately
    $cache_dir = __DIR__ . '/../cache';
    foreach (['stats_kinds.json', 'stats_pubkeys.json'] as $cache_file) {
        $path = $cache_dir . '/' . $cache_file;
        if (is_file($path)) @unlink($path);
    }

    json_response([
        'deleted_count' => $deleted_count,
        'freed_bytes'   => $freed_bytes,
        'freed_human'   => format_bytes($freed_bytes),
        'duration_ms'   => $duration_ms,
    ]);
    exit;
}

// Unsupported method
json_response(['error' => 'Method not allowed']);