use bson::{doc, Bson, Document};
use rustdb_index::IndexEngine;
use tracing::debug;

use crate::context::{CommandContext, ConnectionState, CursorState};
use crate::error::{CommandError, CommandResult};
use crate::transactions;

/// Handle various admin / diagnostic / session / auth commands.
pub async fn handle(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
    command_name: &str,
    connection: &ConnectionState,
) -> CommandResult<Document> {
    match command_name {
        "ping" => Ok(doc! { "ok": 1.0 }),

        "buildInfo" | "buildinfo" => Ok(doc! {
            "version": "7.0.0",
            "gitVersion": "unknown",
            "modules": [],
            "sysInfo": "rustdb",
            "versionArray": [7_i32, 0_i32, 0_i32, 0_i32],
            "ok": 1.0,
        }),

        "serverStatus" => handle_server_status(ctx),

        "hostInfo" => Ok(doc! {
            "system": {
                "hostname": "localhost",
            },
            "ok": 1.0,
        }),

        "whatsmyuri" => Ok(doc! {
            "you": "127.0.0.1:0",
            "ok": 1.0,
        }),

        "getLog" => {
            let _log_type = cmd.get_str("getLog").unwrap_or("global");
            Ok(doc! {
                "totalLinesWritten": 0_i32,
                "log": [],
                "ok": 1.0,
            })
        }

        "replSetGetStatus" => {
            // Not a replica set.
            Ok(doc! {
                "ok": 0.0,
                "errmsg": "not running with --replSet",
                "code": 76_i32,
                "codeName": "NoReplicationEnabled",
            })
        }

        "getCmdLineOpts" => Ok(doc! {
            "argv": ["rustdb"],
            "parsed": {},
            "ok": 1.0,
        }),

        "getParameter" => Ok(doc! {
            "ok": 1.0,
        }),

        "getFreeMonitoringStatus" | "setFreeMonitoring" => Ok(doc! {
            "state": "disabled",
            "ok": 1.0,
        }),

        "getShardMap" | "shardingState" => Ok(doc! {
            "enabled": false,
            "ok": 1.0,
        }),

        "atlasVersion" => Ok(doc! {
            "ok": 0.0,
            "errmsg": "not supported",
            "code": 59_i32,
            "codeName": "CommandNotFound",
        }),

        "connectionStatus" => Ok(handle_connection_status(connection)),

        "createUser" => handle_create_user(cmd, db, ctx).await,

        "updateUser" => handle_update_user(cmd, db, ctx).await,

        "dropUser" => handle_drop_user(cmd, db, ctx).await,

        "usersInfo" => handle_users_info(cmd, db, ctx).await,

        "grantRolesToUser" => handle_grant_roles_to_user(cmd, db, ctx).await,

        "revokeRolesFromUser" => handle_revoke_roles_from_user(cmd, db, ctx).await,

        "listDatabases" => handle_list_databases(cmd, ctx).await,

        "listCollections" => handle_list_collections(cmd, db, ctx).await,

        "create" => handle_create(cmd, db, ctx).await,

        "drop" => handle_drop(cmd, db, ctx).await,

        "dropDatabase" => handle_drop_database(db, ctx).await,

        "renameCollection" => handle_rename_collection(cmd, ctx).await,

        "collStats" | "validate" => handle_coll_stats(cmd, db, ctx, command_name).await,

        "dbStats" => handle_db_stats(db, ctx).await,

        "explain" => Ok(doc! {
            "queryPlanner": {},
            "ok": 1.0,
        }),

        "startSession" => {
            let session_id = uuid::Uuid::new_v4().to_string();
            ctx.sessions.get_or_create_session(&session_id);
            Ok(doc! {
                "id": { "id": &session_id },
                "timeoutMinutes": 30_i32,
                "ok": 1.0,
            })
        }

        "endSessions" | "killSessions" => {
            // Attempt to end listed sessions.
            if let Ok(sessions) = cmd
                .get_array("endSessions")
                .or_else(|_| cmd.get_array("killSessions"))
            {
                for s in sessions {
                    if let Some(sid) = rustdb_txn::SessionEngine::extract_session_id(s) {
                        ctx.sessions.end_session(&sid);
                    }
                }
            }
            Ok(doc! { "ok": 1.0 })
        }

        "commitTransaction" => transactions::commit_transaction_command(cmd, ctx).await,

        "abortTransaction" => transactions::abort_transaction_command(cmd, ctx),

        // Auth stubs - accept silently.
        "saslStart" => Ok(doc! {
            "conversationId": 1_i32,
            "done": true,
            "payload": bson::Binary { subtype: bson::spec::BinarySubtype::Generic, bytes: vec![] },
            "ok": 1.0,
        }),

        "saslContinue" => Ok(doc! {
            "conversationId": 1_i32,
            "done": true,
            "payload": bson::Binary { subtype: bson::spec::BinarySubtype::Generic, bytes: vec![] },
            "ok": 1.0,
        }),

        "authenticate" | "logout" => Ok(doc! { "ok": 1.0 }),

        "currentOp" => Ok(doc! {
            "inprog": [],
            "ok": 1.0,
        }),

        "killOp" | "top" | "profile" | "compact" | "reIndex"
        | "fsync" | "connPoolSync" => Ok(doc! { "ok": 1.0 }),

        other => {
            // Catch-all for any admin command we missed.
            Ok(doc! {
                "ok": 1.0,
                "note": format!("stub response for command: {}", other),
            })
        }
    }
}

fn handle_server_status(ctx: &CommandContext) -> CommandResult<Document> {
    let oplog_stats = ctx.oplog.stats();
    Ok(doc! {
        "host": "localhost",
        "version": "7.0.0",
        "process": "rustdb",
        "uptime": ctx.start_time.elapsed().as_secs() as i64,
        "connections": {
            "current": 0_i32,
            "available": i32::MAX,
        },
        "logicalSessionRecordCache": {
            "activeSessionsCount": ctx.sessions.len() as i64,
        },
        "transactions": {
            "currentActive": ctx.transactions.len() as i64,
        },
        "oplog": {
            "currentSeq": oplog_stats.current_seq as i64,
            "totalEntries": oplog_stats.total_entries as i64,
            "oldestSeq": oplog_stats.oldest_seq as i64,
            "entriesByOp": {
                "insert": oplog_stats.inserts as i64,
                "update": oplog_stats.updates as i64,
                "delete": oplog_stats.deletes as i64,
            },
        },
        "security": {
            "authentication": ctx.auth.enabled(),
            "users": ctx.auth.user_count() as i64,
        },
        "ok": 1.0,
    })
}

fn handle_connection_status(connection: &ConnectionState) -> Document {
    let authenticated_users: Vec<Bson> = connection
        .authenticated_users
        .iter()
        .map(|user| {
            Bson::Document(doc! {
                "user": user.username.clone(),
                "db": user.database.clone(),
            })
        })
        .collect();

    let authenticated_roles: Vec<Bson> = connection
        .authenticated_users
        .iter()
        .flat_map(|user| {
            user.roles
                .iter()
                .map(|role| Bson::Document(role_to_document(&user.database, role)))
        })
        .collect();

    doc! {
        "authInfo": {
            "authenticatedUsers": authenticated_users,
            "authenticatedUserRoles": authenticated_roles,
        },
        "ok": 1.0,
    }
}

async fn handle_create_user(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let username = cmd
        .get_str("createUser")
        .map_err(|_| CommandError::InvalidArgument("missing 'createUser' field".into()))?;
    let password = cmd
        .get_str("pwd")
        .map_err(|_| CommandError::InvalidArgument("missing 'pwd' field".into()))?;
    let roles = parse_roles(cmd, db, "roles")?;
    ctx.auth
        .create_user(db, username, password, roles)
        .map_err(auth_error_to_command_error)?;
    Ok(doc! { "ok": 1.0 })
}

async fn handle_update_user(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let username = cmd
        .get_str("updateUser")
        .map_err(|_| CommandError::InvalidArgument("missing 'updateUser' field".into()))?;
    let password = cmd.get_str("pwd").ok();
    let roles = if cmd.contains_key("roles") {
        Some(parse_roles(cmd, db, "roles")?)
    } else {
        None
    };
    ctx.auth
        .update_user(db, username, password, roles)
        .map_err(auth_error_to_command_error)?;
    Ok(doc! { "ok": 1.0 })
}

async fn handle_drop_user(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let username = cmd
        .get_str("dropUser")
        .map_err(|_| CommandError::InvalidArgument("missing 'dropUser' field".into()))?;
    ctx.auth
        .drop_user(db, username)
        .map_err(auth_error_to_command_error)?;
    Ok(doc! { "ok": 1.0 })
}

async fn handle_users_info(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let username = match cmd.get("usersInfo") {
        Some(Bson::String(name)) => Some(name.as_str()),
        Some(Bson::Document(user_doc)) => user_doc.get_str("user").ok(),
        _ => None,
    };
    let users = ctx.auth.users_info(db, username);
    let user_docs: Vec<Bson> = users
        .into_iter()
        .map(|user| {
            let roles: Vec<Bson> = user
                .roles
                .iter()
                .map(|role| Bson::Document(role_to_document(&user.database, role)))
                .collect();
            Bson::Document(doc! {
                "user": user.username,
                "db": user.database,
                "roles": roles,
                "mechanisms": ["SCRAM-SHA-256"],
            })
        })
        .collect();
    Ok(doc! { "users": user_docs, "ok": 1.0 })
}

async fn handle_grant_roles_to_user(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let username = cmd
        .get_str("grantRolesToUser")
        .map_err(|_| CommandError::InvalidArgument("missing 'grantRolesToUser' field".into()))?;
    let roles = parse_roles(cmd, db, "roles")?;
    ctx.auth
        .grant_roles(db, username, roles)
        .map_err(auth_error_to_command_error)?;
    Ok(doc! { "ok": 1.0 })
}

async fn handle_revoke_roles_from_user(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let username = cmd
        .get_str("revokeRolesFromUser")
        .map_err(|_| CommandError::InvalidArgument("missing 'revokeRolesFromUser' field".into()))?;
    let roles = parse_roles(cmd, db, "roles")?;
    ctx.auth
        .revoke_roles(db, username, roles)
        .map_err(auth_error_to_command_error)?;
    Ok(doc! { "ok": 1.0 })
}

fn parse_roles(cmd: &Document, db: &str, key: &str) -> CommandResult<Vec<String>> {
    let role_values = cmd
        .get_array(key)
        .map_err(|_| CommandError::InvalidArgument(format!("missing '{key}' array")))?;
    let mut roles = Vec::with_capacity(role_values.len());
    for role_value in role_values {
        match role_value {
            Bson::String(role) => roles.push(role.clone()),
            Bson::Document(role_doc) => {
                let role = role_doc
                    .get_str("role")
                    .map_err(|_| CommandError::InvalidArgument("role document missing 'role'".into()))?;
                let role_db = role_doc.get_str("db").unwrap_or(db);
                if role_db == db {
                    roles.push(role.to_string());
                } else {
                    roles.push(format!("{role_db}.{role}"));
                }
            }
            _ => return Err(CommandError::InvalidArgument("roles must be strings or documents".into())),
        }
    }
    Ok(roles)
}

fn role_to_document(default_db: &str, role: &str) -> Document {
    if let Some((role_db, role_name)) = role.split_once('.') {
        doc! { "role": role_name, "db": role_db }
    } else {
        doc! { "role": role, "db": default_db }
    }
}

fn auth_error_to_command_error(error: rustdb_auth::AuthError) -> CommandError {
    match error {
        rustdb_auth::AuthError::UserAlreadyExists(message) => CommandError::DuplicateKey(message),
        rustdb_auth::AuthError::UserNotFound(message) => CommandError::NamespaceNotFound(message),
        rustdb_auth::AuthError::Persistence(message) => CommandError::InternalError(message),
        rustdb_auth::AuthError::AuthenticationFailed => CommandError::AuthenticationFailed,
        rustdb_auth::AuthError::InvalidPayload(message) => CommandError::InvalidArgument(message),
        rustdb_auth::AuthError::UnsupportedMechanism(message) => CommandError::InvalidArgument(message),
        rustdb_auth::AuthError::Disabled => CommandError::Unauthorized("authentication is disabled".into()),
        rustdb_auth::AuthError::UnknownConversation => {
            CommandError::InvalidArgument("unknown SASL conversation".into())
        }
    }
}

/// Handle `listDatabases` command.
async fn handle_list_databases(
    cmd: &Document,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let dbs = ctx.storage.list_databases().await?;

    let name_only = match cmd.get("nameOnly") {
        Some(Bson::Boolean(true)) => true,
        _ => false,
    };

    let filter = match cmd.get("filter") {
        Some(Bson::Document(d)) => Some(d.clone()),
        _ => None,
    };

    let mut db_docs: Vec<Bson> = Vec::new();
    let mut total_size: i64 = 0;

    for db_name in &dbs {
        let mut db_info = doc! { "name": db_name.as_str() };

        if !name_only {
            // Estimate size by counting documents across collections.
            let mut db_size: i64 = 0;
            if let Ok(collections) = ctx.storage.list_collections(db_name).await {
                for coll in &collections {
                    if let Ok(count) = ctx.storage.count(db_name, coll).await {
                        // Rough estimate: 200 bytes per document.
                        db_size += count as i64 * 200;
                    }
                }
            }
            db_info.insert("sizeOnDisk", db_size);
            db_info.insert("empty", db_size == 0);
            total_size += db_size;
        }

        // Apply filter if specified.
        if let Some(ref f) = filter {
            if !rustdb_query::QueryMatcher::matches(&db_info, f) {
                continue;
            }
        }

        db_docs.push(Bson::Document(db_info));
    }

    let mut response = doc! {
        "databases": db_docs,
        "ok": 1.0,
    };

    if !name_only {
        response.insert("totalSize", total_size);
    }

    Ok(response)
}

/// Handle `listCollections` command.
async fn handle_list_collections(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let collections = ctx.storage.list_collections(db).await?;

    let filter = match cmd.get("filter") {
        Some(Bson::Document(d)) => Some(d.clone()),
        _ => None,
    };

    let name_only = match cmd.get("nameOnly") {
        Some(Bson::Boolean(true)) => true,
        _ => false,
    };

    let batch_size = cmd
        .get_document("cursor")
        .ok()
        .and_then(|c| {
            c.get_i32("batchSize")
                .ok()
                .map(|v| v as usize)
                .or_else(|| c.get_i64("batchSize").ok().map(|v| v as usize))
        })
        .unwrap_or(usize::MAX);

    let ns = format!("{}.$cmd.listCollections", db);

    let mut coll_docs: Vec<Document> = Vec::new();

    for coll_name in &collections {
        let info_doc = if name_only {
            doc! {
                "name": coll_name.as_str(),
                "type": "collection",
            }
        } else {
            doc! {
                "name": coll_name.as_str(),
                "type": "collection",
                "options": {},
                "info": {
                    "readOnly": false,
                },
                "idIndex": {
                    "v": 2_i32,
                    "key": { "_id": 1_i32 },
                    "name": "_id_",
                },
            }
        };

        // Apply filter if specified.
        if let Some(ref f) = filter {
            if !rustdb_query::QueryMatcher::matches(&info_doc, f) {
                continue;
            }
        }

        coll_docs.push(info_doc);
    }

    if coll_docs.len() <= batch_size {
        let first_batch: Vec<Bson> = coll_docs.into_iter().map(Bson::Document).collect();

        Ok(doc! {
            "cursor": {
                "id": 0_i64,
                "ns": &ns,
                "firstBatch": first_batch,
            },
            "ok": 1.0,
        })
    } else {
        let first_batch: Vec<Bson> = coll_docs[..batch_size]
            .iter()
            .cloned()
            .map(Bson::Document)
            .collect();

        let remaining: Vec<Document> = coll_docs[batch_size..].to_vec();
        let cursor_id = generate_cursor_id();

        ctx.cursors.insert(
            cursor_id,
            CursorState {
                documents: remaining,
                position: 0,
                database: db.to_string(),
                collection: String::new(),
            },
        );

        Ok(doc! {
            "cursor": {
                "id": cursor_id,
                "ns": &ns,
                "firstBatch": first_batch,
            },
            "ok": 1.0,
        })
    }
}

/// Handle `create` command.
async fn handle_create(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let coll = cmd
        .get_str("create")
        .map_err(|_| CommandError::InvalidArgument("missing 'create' field".into()))?;

    debug!(db = db, collection = coll, "create command");

    // Create database (ignore AlreadyExists).
    if let Err(e) = ctx.storage.create_database(db).await {
        let msg = e.to_string();
        if !msg.contains("AlreadyExists") && !msg.contains("already exists") {
            return Err(CommandError::StorageError(msg));
        }
    }

    // Create collection.
    if let Err(e) = ctx.storage.create_collection(db, coll).await {
        let msg = e.to_string();
        if msg.contains("AlreadyExists") || msg.contains("already exists") {
            return Err(CommandError::NamespaceExists(format!("{}.{}", db, coll)));
        }
        return Err(CommandError::StorageError(msg));
    }

    // Initialize index engine for the new collection.
    let ns_key = format!("{}.{}", db, coll);
    ctx.indexes
        .entry(ns_key)
        .or_insert_with(IndexEngine::new);

    Ok(doc! { "ok": 1.0 })
}

/// Handle `drop` command.
async fn handle_drop(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let coll = cmd
        .get_str("drop")
        .map_err(|_| CommandError::InvalidArgument("missing 'drop' field".into()))?;

    let ns_key = format!("{}.{}", db, coll);

    debug!(db = db, collection = coll, "drop command");

    // Check if collection exists.
    match ctx.storage.collection_exists(db, coll).await {
        Ok(false) => {
            return Err(CommandError::NamespaceNotFound(format!(
                "ns not found: {}",
                ns_key
            )));
        }
        Err(_) => {}
        _ => {}
    }

    // Drop from storage.
    ctx.storage.drop_collection(db, coll).await?;

    // Remove from indexes.
    ctx.indexes.remove(&ns_key);

    // Count of indexes that were on this collection (at least _id_).
    Ok(doc! {
        "ns": &ns_key,
        "nIndexesWas": 1_i32,
        "ok": 1.0,
    })
}

/// Handle `dropDatabase` command.
async fn handle_drop_database(
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    debug!(db = db, "dropDatabase command");

    // Remove all index entries for this database.
    let prefix = format!("{}.", db);
    let keys_to_remove: Vec<String> = ctx
        .indexes
        .iter()
        .filter(|entry| entry.key().starts_with(&prefix))
        .map(|entry| entry.key().clone())
        .collect();

    for key in keys_to_remove {
        ctx.indexes.remove(&key);
    }

    // Drop from storage.
    ctx.storage.drop_database(db).await?;

    Ok(doc! {
        "dropped": db,
        "ok": 1.0,
    })
}

/// Handle `renameCollection` command.
async fn handle_rename_collection(
    cmd: &Document,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let source_ns = cmd
        .get_str("renameCollection")
        .map_err(|_| CommandError::InvalidArgument("missing 'renameCollection' field".into()))?;

    let target_ns = cmd
        .get_str("to")
        .map_err(|_| CommandError::InvalidArgument("missing 'to' field".into()))?;

    let drop_target = match cmd.get("dropTarget") {
        Some(Bson::Boolean(b)) => *b,
        _ => false,
    };

    // Parse "db.collection" format.
    let (source_db, source_coll) = parse_namespace(source_ns)?;
    let (target_db, target_coll) = parse_namespace(target_ns)?;

    debug!(
        source = source_ns,
        target = target_ns,
        drop_target = drop_target,
        "renameCollection command"
    );

    // If cross-database rename, that's more complex. For now, support same-db rename.
    if source_db != target_db {
        return Err(CommandError::InvalidArgument(
            "cross-database renameCollection not yet supported".into(),
        ));
    }

    // If dropTarget, drop the target collection first.
    if drop_target {
        let _ = ctx.storage.drop_collection(target_db, target_coll).await;
        let target_ns_key = format!("{}.{}", target_db, target_coll);
        ctx.indexes.remove(&target_ns_key);
    } else {
        // Check if target already exists.
        if let Ok(true) = ctx.storage.collection_exists(target_db, target_coll).await {
            return Err(CommandError::NamespaceExists(target_ns.to_string()));
        }
    }

    // Rename in storage.
    ctx.storage
        .rename_collection(source_db, source_coll, target_coll)
        .await?;

    // Update index engine: move from old namespace to new.
    let source_ns_key = format!("{}.{}", source_db, source_coll);
    let target_ns_key = format!("{}.{}", target_db, target_coll);

    if let Some((_, engine)) = ctx.indexes.remove(&source_ns_key) {
        ctx.indexes.insert(target_ns_key, engine);
    }

    Ok(doc! { "ok": 1.0 })
}

/// Handle `collStats` command.
async fn handle_coll_stats(
    cmd: &Document,
    db: &str,
    ctx: &CommandContext,
    command_name: &str,
) -> CommandResult<Document> {
    let coll = cmd
        .get_str(command_name)
        .unwrap_or("unknown");

    let ns = format!("{}.{}", db, coll);

    let count = ctx
        .storage
        .count(db, coll)
        .await
        .unwrap_or(0);

    let n_indexes = match ctx.indexes.get(&ns) {
        Some(engine) => engine.list_indexes().len() as i32,
        None => 1_i32,
    };

    // Rough size estimate.
    let data_size = count as i64 * 200;

    Ok(doc! {
        "ns": &ns,
        "count": count as i64,
        "size": data_size,
        "avgObjSize": if count > 0 { 200_i64 } else { 0_i64 },
        "storageSize": data_size,
        "nindexes": n_indexes,
        "totalIndexSize": 0_i64,
        "ok": 1.0,
    })
}

/// Handle `dbStats` command.
async fn handle_db_stats(
    db: &str,
    ctx: &CommandContext,
) -> CommandResult<Document> {
    let collections = ctx
        .storage
        .list_collections(db)
        .await
        .unwrap_or_default();

    let num_collections = collections.len() as i32;
    let mut total_objects: i64 = 0;
    let mut total_indexes: i32 = 0;

    for coll in &collections {
        if let Ok(count) = ctx.storage.count(db, coll).await {
            total_objects += count as i64;
        }

        let ns_key = format!("{}.{}", db, coll);
        if let Some(engine) = ctx.indexes.get(&ns_key) {
            total_indexes += engine.list_indexes().len() as i32;
        } else {
            total_indexes += 1; // At least _id_.
        }
    }

    let data_size = total_objects * 200;

    Ok(doc! {
        "db": db,
        "collections": num_collections,
        "objects": total_objects,
        "avgObjSize": if total_objects > 0 { 200_i64 } else { 0_i64 },
        "dataSize": data_size,
        "storageSize": data_size,
        "indexes": total_indexes,
        "indexSize": 0_i64,
        "ok": 1.0,
    })
}

/// Parse a namespace string "db.collection" into (db, collection).
fn parse_namespace(ns: &str) -> CommandResult<(&str, &str)> {
    let dot_pos = ns.find('.').ok_or_else(|| {
        CommandError::InvalidArgument(format!(
            "invalid namespace '{}': expected 'db.collection' format",
            ns
        ))
    })?;

    let db = &ns[..dot_pos];
    let coll = &ns[dot_pos + 1..];

    if db.is_empty() || coll.is_empty() {
        return Err(CommandError::InvalidArgument(format!(
            "invalid namespace '{}': db and collection must not be empty",
            ns
        )));
    }

    Ok((db, coll))
}

/// Generate a pseudo-random cursor ID.
fn generate_cursor_id() -> i64 {
    use std::collections::hash_map::RandomState;
    use std::hash::{BuildHasher, Hasher};
    let s = RandomState::new();
    let mut hasher = s.build_hasher();
    hasher.write_u64(
        std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .unwrap_or_default()
            .as_nanos() as u64,
    );
    let id = hasher.finish() as i64;
    if id == 0 {
        1
    } else {
        id.abs()
    }
}