<?php
declare(strict_types=1);

header('Content-Type: application/json; charset=utf-8');
header('Cache-Control: no-store');

require __DIR__ . '/im_web_bootstrap.php';

class UserActionException extends RuntimeException
{
}

function resolveActionUserId(string $value): string
{
    if ($value === '') {
        return '';
    }

    $db = imDb();
    $statement = $db->prepare(
        'select `_uid` from `t_user` where `_uid` = ? or `_mobile` = ? or `_name` = ? limit 1'
    );
    $statement->execute([$value, $value, $value]);
    $uid = $statement->fetchColumn();

    return is_string($uid) && $uid !== '' ? $uid : $value;
}

function messageTimestampMs(string $messageUid): int
{
    return (((int)$messageUid) >> 21) + 1514736000000;
}

function nowTimestampMs(): int
{
    return (int)floor(microtime(true) * 1000);
}

function recallLimitMinutes(): float
{
    $statement = imAppDb()->prepare(
        'select `conf_value` from `system_conf`'
        . ' where `conf_name` = ? and `is_valid` = 1 limit 1'
    );
    $statement->execute(['RetractMessage']);
    $value = trim((string)($statement->fetchColumn() ?: '0'));

    if ($value === '' || !is_numeric($value)) {
        return 0.0;
    }

    return max(0.0, (float)$value);
}

function assertRecallWithinLimit(string $messageUid): void
{
    $limitMinutes = recallLimitMinutes();
    if ($limitMinutes <= 0) {
        return;
    }

    $messageAgeMs = nowTimestampMs() - messageTimestampMs($messageUid);
    $limitMs = (int)round($limitMinutes * 60 * 1000);
    if ($messageAgeMs > $limitMs) {
        throw new UserActionException('已超过可撤回时间');
    }
}

function fetchActionMessageRow(string $messageUid): array
{
    $table = imMessageTable($messageUid);
    $statement = imDb()->prepare(
        'select `_mid`, `_from`, `_content_type`, `_searchable_key` from `' . $table . '` where `_mid` = ? limit 1'
    );
    $statement->execute([$messageUid]);
    $row = $statement->fetch();

    return is_array($row) ? $row : [];
}

function ensureMessageEditsTable(): void
{
    imDb()->exec(
        'create table if not exists `t_web_message_edits` ('
        . '`message_uid` varchar(32) not null,'
        . '`editor_uid` varchar(64) not null,'
        . '`edited_text` text null,'
        . '`edited_at_ms` bigint not null,'
        . '`created_at` datetime not null default current_timestamp,'
        . '`updated_at` datetime null default current_timestamp on update current_timestamp,'
        . 'primary key (`message_uid`),'
        . 'key `idx_editor_uid` (`editor_uid`),'
        . 'key `idx_edited_at_ms` (`edited_at_ms`)'
        . ') engine=InnoDB default charset=utf8mb4'
    );
}

function editTextMessage(string $operatorId, string $messageUid, string $text): array
{
    $row = fetchActionMessageRow($messageUid);
    if (!$row) {
        return editWebGroupMessage($operatorId, $messageUid, $text);
    }
    if ((string)$row['_from'] !== $operatorId) {
        throw new UserActionException('只能编辑自己发送的消息');
    }
    if ((int)$row['_content_type'] !== 1) {
        throw new UserActionException('只能编辑文字消息');
    }

    $editedAt = nowTimestampMs();
    $table = imMessageTable($messageUid);
    $update = imDb()->prepare('update `' . $table . '` set `_searchable_key` = ? where `_mid` = ?');
    $update->execute([$text, $messageUid]);

    ensureMessageEditsTable();
    $upsert = imDb()->prepare(
        'insert into `t_web_message_edits` (`message_uid`, `editor_uid`, `edited_text`, `edited_at_ms`)'
        . ' values (?, ?, ?, ?)'
        . ' on duplicate key update'
        . ' `editor_uid` = values(`editor_uid`),'
        . ' `edited_text` = values(`edited_text`),'
        . ' `edited_at_ms` = values(`edited_at_ms`),'
        . ' `updated_at` = current_timestamp'
    );
    $upsert->execute([$messageUid, $operatorId, $text, $editedAt]);

    return [
        'messageUid' => $messageUid,
        'text' => $text,
        'editedAt' => $editedAt,
    ];
}

function fetchWebGroupActionMessage(string $messageUid): array
{
    ensureWebImAppTables();
    $statement = imAppDb()->prepare(
        'select m.*, g.`category` from `t_web_group_messages` m'
        . ' join `t_web_groups` g on g.`group_id` = m.`group_id` and g.`deleted` = 0'
        . ' where m.`message_uid` = ? limit 1'
    );
    $statement->execute([$messageUid]);
    $row = $statement->fetch();

    return is_array($row) ? $row : [];
}

function editWebGroupMessage(string $operatorId, string $messageUid, string $text): array
{
    $row = fetchWebGroupActionMessage($messageUid);
    if (!$row) {
        throw new UserActionException('消息不存在');
    }
    if ((string)$row['sender_uid'] !== $operatorId) {
        throw new UserActionException('只能编辑自己发送的消息');
    }
    if ((int)($row['recalled'] ?? 0) !== 0) {
        throw new UserActionException('已撤回的消息请重新编辑发送');
    }

    $editedAt = nowTimestampMs();
    $update = imAppDb()->prepare(
        'update `t_web_group_messages` set `text` = ?, `edited_at_ms` = ? where `message_uid` = ?'
    );
    $update->execute([$text, $editedAt, $messageUid]);
    $groupUpdate = imAppDb()->prepare('update `t_web_groups` set `updated_at_ms` = ? where `group_id` = ?');
    $groupUpdate->execute([$editedAt, (string)$row['group_id']]);

    return [
        'messageUid' => $messageUid,
        'text' => $text,
        'editedAt' => $editedAt,
    ];
}

function webGroupMemberRoleForAction(string $groupId, string $userId): string
{
    $statement = imAppDb()->prepare(
        'select `role` from `t_web_group_members`'
        . ' where `group_id` = ? and `user_id` = ? and `status` = 0 limit 1'
    );
    $statement->execute([$groupId, $userId]);
    $role = $statement->fetchColumn();

    return is_string($role) ? $role : '';
}

function recallWebGroupMessage(string $operatorId, string $messageUid): bool
{
    $row = fetchWebGroupActionMessage($messageUid);
    if (!$row) {
        return false;
    }
    $isSender = (string)$row['sender_uid'] === $operatorId;
    if (!$isSender) {
        $role = webGroupMemberRoleForAction((string)$row['group_id'], $operatorId);
        if (!in_array($role, ['owner', 'admin'], true)) {
            throw new UserActionException('只有群主或管理员可以撤回他人消息');
        }
    }
    assertRecallWithinLimit($messageUid);

    $now = nowTimestampMs();
    $update = imAppDb()->prepare(
        'update `t_web_group_messages` set `recalled` = 1 where `message_uid` = ?'
    );
    $update->execute([$messageUid]);
    $groupUpdate = imAppDb()->prepare('update `t_web_groups` set `updated_at_ms` = ? where `group_id` = ?');
    $groupUpdate->execute([$now, (string)$row['group_id']]);

    return true;
}

$payload = readJsonPayload();
$action = trim((string)($payload['action'] ?? ''));
$userId = trim((string)($payload['userId'] ?? ''));
$messageUidText = trim((string)($payload['messageUid'] ?? ''));
$messageUid = ctype_digit($messageUidText) ? (int)$messageUidText : 0;

if ($action === '' || $messageUid <= 0) {
    respond(400, '缺少操作类型或消息ID');
}

try {
    if ($action === 'recall') {
        if ($userId === '') {
            respond(400, '缺少操作者ID');
        }
        $userId = resolveActionUserId($userId);
        $row = fetchActionMessageRow($messageUidText);
        if (!$row && recallWebGroupMessage($userId, $messageUidText)) {
            respond(0, 'success', [
                'messageUid' => (string)$messageUid,
                'action' => $action,
            ]);
        }
        if (!$row) {
            throw new UserActionException('消息不存在');
        }
        assertRecallWithinLimit($messageUidText);
        requireImSuccess(imAdminPost('/admin/message/recall', [
            'operator' => $userId,
            'messageUid' => $messageUid,
            'userRecall' => true,
            'isUserRecall' => true,
        ]), '撤回失败');

        respond(0, 'success', [
            'messageUid' => (string)$messageUid,
            'action' => $action,
        ]);
    }

    if ($action === 'edit') {
        if ($userId === '') {
            respond(400, '缺少操作者ID');
        }
        $text = trim((string)($payload['text'] ?? ''));
        if ($text === '') {
            respond(400, '编辑内容不能为空');
        }
        if (mb_strlen($text, 'UTF-8') > 5000) {
            respond(400, '编辑内容过长');
        }

        $userId = resolveActionUserId($userId);
        respond(0, 'success', [
            'message' => editTextMessage($userId, $messageUidText, $text),
            'action' => $action,
        ]);
    }

    if ($action === 'delete') {
        requireImSuccess(imAdminPost('/admin/message/delete', [
            'messageUid' => $messageUid,
        ]), '删除失败');

        respond(0, 'success', [
            'messageUid' => (string)$messageUid,
            'action' => $action,
        ]);
    }

    respond(400, '不支持的消息操作');
} catch (Throwable $error) {
    respond($error instanceof UserActionException ? 400 : 500, $error->getMessage() ?: '消息操作失败');
}