//! The web vault's `VaultCore`: the same operations as kv-ffi's, over [`WebStore`] and an injected
//! [`kv_sync::DeviceSigner`]. Portable Rust (no JS types), so it is also tested natively, including
//! against kv-sync's test server and against kv-ffi.
//!
//! It deliberately mirrors `kv-ffi/src/lib.rs` (and its `passkeys`/`import` modules); crypto, the
//! item model, the store contract and the sync engine are the shared crates, so the bytes on the
//! wire and in storage are identical. Differences from kv-ffi:
//! * no Local Unlock Key (biometric unlock): the browser has no keystore that can gate a key behind
//!   user presence, so every unlock needs the master password and Secret Key;
//! * no passkey authenticator calls (`create_passkey`/`get_assertion`): the web vault only lists and
//!   deletes passkeys;
//! * no SPKI pins: the browser does TLS for the page's own origin;
//! * `sync_now` fails with `Busy` instead of queueing when a sync is already running.

use std::sync::{
    atomic::{AtomicBool, Ordering},
    Arc, Mutex,
};

use kv_crypto::{
    aad::{Aad, ObjectType},
    aead::SymKey,
    kdf,
    keys::{open_item, seal_item, AccountKeyset, SealedItem},
    secret_key::SecretKey,
};
use kv_model::{generator, matching, totp::Totp, Item, ItemKind, Passkey};
use kv_proto::{b64, DeviceEnroll, Envelope, ItemRecord, KdfParams, Platform};
use kv_store::{HistoryEntry, LocalItem, Store, VaultRow};
use kv_sync::{ApiClient, DeviceSigner, LoginOutcome, ServerConfig, SyncContext, SyncError};
use serde::{Deserialize, Serialize};
use uuid::Uuid;
use zeroize::Zeroizing;

use crate::{
    dto::*,
    error::{internal, CoreError, Result},
    store::WebStore,
};

pub const META_ACCOUNT: &str = "account";
pub const META_SERVER: &str = "server";
pub const META_SESSION: &str = "session";

/// Everything needed to unlock: all public or wrapped. Same JSON as kv-ffi's `AccountRecord`
/// (minus the native-only `local_unlock`), so a record moves between the two unchanged.
#[derive(Clone, Serialize, Deserialize)]
pub struct AccountRecord {
    pub account_id: Uuid,
    pub kdf: KdfParams,
    pub wrapped_keyset: Envelope,
    #[serde(with = "b64")]
    pub enc_pk: Vec<u8>,
    #[serde(with = "b64")]
    pub sig_pk: Vec<u8>,
    pub primary_vault: Uuid,
}

#[derive(Clone, Serialize, Deserialize)]
struct ServerRecord {
    url: String,
    pins: Vec<String>,
}

/// Decrypted key material. Lives only in wasm memory; zeroized on drop (`lock`).
#[derive(Clone)]
struct Unlocked {
    keyset: Arc<AccountKeyset>,
    vault_key: Arc<SymKey>,
    /// OPAQUE password, kept while unlocked so an expired session can be renewed without prompting.
    auth_input: Option<Zeroizing<[u8; 32]>>,
}

struct Device {
    signer: Arc<dyn DeviceSigner>,
    name: String,
    platform: Platform,
}

#[derive(Default)]
struct Inner {
    account: Option<AccountRecord>,
    unlocked: Option<Unlocked>,
    server: Option<ServerRecord>,
    device: Option<Device>,
    api: Option<Arc<ApiClient>>,
}

pub struct WebCore {
    store: Arc<WebStore>,
    inner: Mutex<Inner>,
    syncing: AtomicBool,
}

struct SyncGuard<'a>(&'a AtomicBool);

impl Drop for SyncGuard<'_> {
    fn drop(&mut self) {
        self.0.store(false, Ordering::Release);
    }
}

pub fn now() -> i64 {
    kv_sync::unix_now() as i64
}

impl WebCore {
    pub fn new(store: Arc<WebStore>) -> Result<Self> {
        let account = store
            .get_meta(META_ACCOUNT)?
            .map(|b| serde_json::from_slice::<AccountRecord>(&b))
            .transpose()
            .map_err(internal)?;
        let server = store.get_meta(META_SERVER)?.and_then(|b| serde_json::from_slice::<ServerRecord>(&b).ok());
        Ok(Self {
            store,
            inner: Mutex::new(Inner { account, server, ..Default::default() }),
            syncing: AtomicBool::new(false),
        })
    }

    pub fn store(&self) -> &Arc<WebStore> {
        &self.store
    }

    fn lock_inner(&self) -> std::sync::MutexGuard<'_, Inner> {
        self.inner.lock().unwrap_or_else(|p| p.into_inner())
    }

    // ------------------------------------------------------------ account and session

    /// Creates the account and its first vault, leaving it unlocked. Returns the Secret Key display
    /// string for the Emergency Kit.
    pub fn create_account(&self, master_password: &str) -> Result<String> {
        if master_password.chars().count() < 10 {
            return Err(CoreError::Invalid { msg: "master password must be at least 10 characters".into() });
        }
        let mut inner = self.lock_inner();
        if inner.account.is_some() {
            return Err(CoreError::Invalid { msg: "an account already exists in this browser".into() });
        }
        let account_id = Uuid::new_v4();
        let secret_key = SecretKey::generate();
        let params = kdf::default_params();
        let derived = kdf::derive_keys(master_password, &secret_key, account_id, &params)?;
        let auk = SymKey::from_bytes(Uuid::nil(), *derived.auk);
        let keyset = AccountKeyset::generate(account_id);
        let wrapped_keyset = keyset.wrap(&auk)?;
        let vault_id = Uuid::new_v4();
        let vault_key = self.create_vault(&keyset, vault_id)?;
        let account = AccountRecord {
            account_id,
            kdf: params,
            wrapped_keyset,
            enc_pk: keyset.enc.public_bytes(),
            sig_pk: keyset.sig_public().to_vec(),
            primary_vault: vault_id,
        };
        self.save_account(&account)?;
        inner.account = Some(account);
        inner.unlocked = Some(Unlocked {
            keyset: Arc::new(keyset),
            vault_key: Arc::new(vault_key),
            auth_input: Some(derived.auth_input),
        });
        Ok(secret_key.to_display().to_string())
    }

    pub fn unlock(&self, master_password: &str, secret_key: &str) -> Result<()> {
        let mut inner = self.lock_inner();
        let acct = inner.account.clone().ok_or(CoreError::NoAccount)?;
        let sk = SecretKey::parse(secret_key)?;
        let derived = kdf::derive_keys(master_password, &sk, acct.account_id, &acct.kdf)?;
        let auk = SymKey::from_bytes(Uuid::nil(), *derived.auk);
        let keyset = AccountKeyset::unwrap(acct.account_id, &auk, &acct.wrapped_keyset)?;
        let vault_key = self.open_vault_key(&keyset, acct.primary_vault)?;
        inner.unlocked = Some(Unlocked {
            keyset: Arc::new(keyset),
            vault_key: Arc::new(vault_key),
            auth_input: Some(derived.auth_input),
        });
        Ok(())
    }

    /// Drops all decrypted key material (keysets, vault key and OPAQUE input are zeroized on drop).
    pub fn lock(&self) {
        let mut inner = self.lock_inner();
        inner.unlocked = None;
    }

    pub fn is_locked(&self) -> bool {
        self.lock_inner().unlocked.is_none()
    }

    pub fn has_account(&self) -> bool {
        self.lock_inner().account.is_some()
    }

    pub fn account_id(&self) -> Result<String> {
        Ok(self.lock_inner().account.as_ref().ok_or(CoreError::NoAccount)?.account_id.to_string())
    }

    /// Ed25519 public key of the account (hex), shown when pairing devices.
    pub fn account_fingerprint(&self) -> Result<String> {
        let (_, u) = self.unlocked_snapshot()?;
        Ok(u.keyset.sig_public().iter().map(|b| format!("{b:02x}")).collect())
    }

    /// Forgets everything stored for this browser (account record, replica, session). The device key
    /// is removed by the wasm layer.
    pub fn wipe(&self) -> Result<()> {
        let mut inner = self.lock_inner();
        self.store.wipe()?;
        *inner = Inner::default();
        Ok(())
    }

    // ------------------------------------------------------------ items

    pub fn list_items(&self) -> Result<Vec<ItemSummary>> {
        let (acct, u) = self.unlocked_snapshot()?;
        let mut out: Vec<ItemSummary> = self.all_items(&acct, &u)?.iter().map(summary).collect();
        out.sort_by(|a, b| {
            b.favorite.cmp(&a.favorite).then_with(|| a.title.to_lowercase().cmp(&b.title.to_lowercase()))
        });
        Ok(out)
    }

    pub fn get_item(&self, id: &str) -> Result<ItemDto> {
        let id = parse_id(id)?;
        let (acct, u) = self.unlocked_snapshot()?;
        let li = self.store.get(acct.primary_vault, id)?.ok_or(CoreError::NotFound)?;
        Ok(to_dto(&decrypt(&acct, &u.vault_key, &li.record)?.ok_or(CoreError::NotFound)?))
    }

    /// Inserts or updates an item. Returns its id. The previous version goes to the item's history.
    pub fn save_item(&self, item: ItemDto) -> Result<String> {
        let (acct, u) = self.unlocked_snapshot()?;
        let vault = acct.primary_vault;
        let now = now();
        let id = if item.id.is_empty() { Uuid::new_v4() } else { parse_id(&item.id)? };
        let existing = self.store.get(vault, id)?;
        let previous = match &existing {
            Some(li) => decrypt(&acct, &u.vault_key, &li.record)?,
            None => None,
        };
        let mut model = match &previous {
            // Keep fields the DTO does not carry (passkeys, android apps, unknown future fields).
            Some(p) => p.clone(),
            None => Item::new_login(item.title.clone(), now),
        };
        model.id = id;
        model.kind = kind_from_dto(item.kind);
        model.title = item.title;
        model.username = item.username;
        model.password = item.password;
        model.urls = item.urls;
        model.totp = item.totp;
        model.notes = item.notes;
        model.favorite = item.favorite;
        model.tags = item.tags;
        model.modified_at = now.max(previous.as_ref().map_or(0, |p| p.modified_at + 1));
        self.write_item(&acct, &u, &mut model, existing.filter(|_| previous.is_some()), false)?;
        Ok(id.to_string())
    }

    pub fn delete_item(&self, id: &str) -> Result<()> {
        let id = parse_id(id)?;
        let (acct, u) = self.unlocked_snapshot()?;
        let vault = acct.primary_vault;
        let li = self.store.get(vault, id)?.filter(|li| !li.record.deleted).ok_or(CoreError::NotFound)?;
        if li.base.is_none() {
            // Never reached the server: just forget it.
            return Ok(self.store.remove(vault, id)?);
        }
        let seq = kv_sync::engine::next_local_version(self.store.as_ref(), acct.account_id, vault, &u.vault_key, id)?;
        let tomb =
            kv_sync::engine::seal_tombstone(acct.account_id, vault, &u.vault_key, id, seq, li.record.updated_by)?;
        Ok(self.store.put_local(vault, &tomb)?)
    }

    /// Earlier versions of an item (local edits and merge losers), newest first. At most 10.
    pub fn item_history(&self, id: &str) -> Result<Vec<ItemDto>> {
        let id = parse_id(id)?;
        let (acct, u) = self.unlocked_snapshot()?;
        let mut out = Vec::new();
        for h in self.store.history(acct.primary_vault, id)? {
            let rec = ItemRecord {
                item_id: id,
                revision: h.revision,
                deleted: false,
                wrapped_item_key: Some(h.wrapped_item_key),
                payload: Some(h.payload),
                updated_by: Uuid::nil(),
                updated_at: String::new(),
            };
            if let Some(item) = decrypt(&acct, &u.vault_key, &rec)? {
                out.push(to_dto(&item));
            }
        }
        Ok(out)
    }

    /// Items whose URLs match a page URL, best match first.
    pub fn items_for_url(&self, page_url: &str) -> Result<Vec<ItemSummary>> {
        let (acct, u) = self.unlocked_snapshot()?;
        let mut scored = Vec::new();
        for item in self.all_items(&acct, &u)? {
            let best = item.urls.iter().map(|url| matching::match_url(url, page_url)).max();
            if let Some(level) = best.filter(|l| *l > matching::MatchLevel::None) {
                scored.push((level, summary(&item)));
            }
        }
        scored.sort_by(|a, b| b.0.cmp(&a.0).then_with(|| a.1.title.cmp(&b.1.title)));
        Ok(scored.into_iter().map(|(_, s)| s).collect())
    }

    // ------------------------------------------------------------ passkeys (list / delete only)

    pub fn list_passkeys(&self) -> Result<Vec<PasskeySummary>> {
        let (acct, u) = self.unlocked_snapshot()?;
        let mut out = Vec::new();
        for item in self.all_items(&acct, &u)? {
            out.extend(item.passkeys.iter().map(|pk| passkey_summary(&item, pk)));
        }
        Ok(out)
    }

    /// Removes one passkey from its item (the item stays; the old version goes to history).
    pub fn delete_passkey(&self, credential_id: &[u8]) -> Result<()> {
        let (acct, u) = self.unlocked_snapshot()?;
        for li in self.store.list(acct.primary_vault)? {
            let Some(mut item) = decrypt(&acct, &u.vault_key, &li.record)? else { continue };
            if item.passkeys.iter().any(|pk| pk.credential_id == credential_id) {
                item.passkeys.retain(|pk| pk.credential_id != credential_id);
                return self.write_item(&acct, &u, &mut item, Some(li), true);
            }
        }
        Err(CoreError::NotFound)
    }

    // ------------------------------------------------------------ import / export

    pub fn import_preview(&self, data: &[u8], format: ImportFormat) -> Result<ImportPreview> {
        let (acct, u) = self.unlocked_snapshot()?;
        let mut parsed = parse_import(data, format)?;
        let existing = self.all_items(&acct, &u)?;
        let mut preview = ImportPreview {
            total: parsed.items.len() as u32,
            logins: parsed.count(ItemKind::Login),
            secure_notes: parsed.count(ItemKind::SecureNote),
            cards: parsed.count(ItemKind::Card),
            identities: parsed.count(ItemKind::Identity),
            duplicates: 0,
            attachments_skipped: parsed.attachments_skipped,
            warnings: std::mem::take(&mut parsed.warnings),
        };
        let items = std::mem::take(&mut parsed.items);
        preview.duplicates =
            kv_import::plan(items, existing.iter().map(kv_import::dedup::key), kv_import::DuplicatePolicy::Skip)
                .skipped;
        Ok(preview)
    }

    pub fn import_commit(&self, data: &[u8], format: ImportFormat, options: ImportOptions) -> Result<ImportReport> {
        let (acct, u) = self.unlocked_snapshot()?;
        let mut parsed = parse_import(data, format)?;
        let existing = self.all_items(&acct, &u)?;
        let policy = match options.duplicates {
            DuplicateHandling::Skip => kv_import::DuplicatePolicy::Skip,
            DuplicateHandling::AddSuffix => kv_import::DuplicatePolicy::AddSuffix,
        };
        let plan =
            kv_import::plan(std::mem::take(&mut parsed.items), existing.iter().map(kv_import::dedup::key), policy);
        let mut item_ids = Vec::with_capacity(plan.to_add.len());
        for mut model in plan.to_add {
            // Every imported item is new: fresh id, seq 1, every model field kept.
            model.id = Uuid::new_v4();
            model.modified_at = model.modified_at.max(model.created_at);
            self.write_item(&acct, &u, &mut model, None, false)?;
            item_ids.push(model.id.to_string());
        }
        Ok(ImportReport {
            imported: item_ids.len() as u32,
            skipped_duplicates: plan.skipped,
            renamed_duplicates: plan.renamed,
            attachments_skipped: parsed.attachments_skipped,
            warnings: std::mem::take(&mut parsed.warnings),
            item_ids,
        })
    }

    /// All items as a passphrase-encrypted `.kvex` file (restore with `KestroveEncrypted`).
    pub fn export_encrypted(&self, passphrase: &str) -> Result<Vec<u8>> {
        let passphrase = Zeroizing::new(passphrase.to_string());
        let (acct, u) = self.unlocked_snapshot()?;
        let items = self.all_items(&acct, &u)?;
        Ok(kv_import::export::encrypt(&items, &passphrase, now())?)
    }

    // ------------------------------------------------------------ sync server

    /// Sets the server URL (https; http only for localhost). Pins are stored for parity with the
    /// apps but not enforced in the browser.
    pub fn configure_server(&self, url: &str, spki_pins: Vec<String>) -> Result<()> {
        kv_sync::transport::normalize_base_url(url)?;
        for p in &spki_pins {
            kv_sync::transport::parse_pin(p)?;
        }
        let rec = ServerRecord { url: url.to_string(), pins: spki_pins };
        self.store.put_meta(META_SERVER, &serde_json::to_vec(&rec).map_err(internal)?)?;
        let mut inner = self.lock_inner();
        inner.server = Some(rec);
        inner.api = None;
        Ok(())
    }

    pub fn set_device_signer(&self, signer: Arc<dyn DeviceSigner>, name: &str, platform: Platform) {
        let mut inner = self.lock_inner();
        inner.device = Some(Device { signer, name: name.to_string(), platform });
        inner.api = None;
    }

    pub fn device_id(&self) -> Option<Uuid> {
        self.lock_inner().device.as_ref().map(|d| d.signer.device_id())
    }

    pub fn device_key_fingerprint(&self) -> Result<String> {
        let inner = self.lock_inner();
        let d = inner.device.as_ref().ok_or(CoreError::NotConfigured)?;
        Ok(device_key_fingerprint(&d.signer.public_key()))
    }

    pub async fn server_info(&self) -> Result<ServerInfoDto> {
        let info = self.api()?.server_info().await?;
        Ok(ServerInfoDto {
            version: info.version,
            api: info.api,
            setup_open: info.setup_open,
            min_client: info.min_client,
        })
    }

    /// First device only: registers the account with a fresh server using its one-time setup token.
    pub async fn register_account(&self, setup_token: &str) -> Result<()> {
        let api = self.api()?;
        let (acct, u) = self.unlocked_snapshot()?;
        let auth = u.auth_input.clone().ok_or(CoreError::NotAuthenticated)?;
        let device = self.enroll()?;
        api.register(
            setup_token,
            acct.account_id,
            &acct.kdf,
            auth.as_ref(),
            acct.enc_pk.clone(),
            acct.sig_pk.clone(),
            acct.wrapped_keyset.clone(),
            device,
        )
        .await?;
        self.do_login(&api, acct.account_id, auth.as_ref(), None).await.map(|_| ())
    }

    /// Logs in with the master password and Secret Key. A browser with no account fetches it from the
    /// server; call `sync_now` afterwards to download the vault.
    pub async fn login(&self, master_password: &str, secret_key: &str, totp: Option<String>) -> Result<LoginResult> {
        let api = self.api()?;
        let sk = SecretKey::parse(secret_key)?;
        let local = self.lock_inner().account.clone();
        let (account_id, kdf_params) = match &local {
            Some(a) => (a.account_id, a.kdf.clone()),
            None => {
                let pre = api.prelogin().await?;
                (pre.account_id, pre.kdf)
            }
        };
        // A downgraded KDF from the server is refused before any work is done.
        kdf::validate(&kdf_params)?;
        let derived = kdf::derive_keys(master_password, &sk, account_id, &kdf_params)?;
        if self.do_login(&api, account_id, derived.auth_input.as_ref(), totp).await? == LoginResult::PendingApproval {
            return Ok(LoginResult::PendingApproval);
        }
        let auk = SymKey::from_bytes(Uuid::nil(), *derived.auk);
        let acct = match local {
            Some(a) => a,
            None => {
                let info = api.account().await?;
                if info.account_id != account_id {
                    return Err(internal("server returned a different account"));
                }
                kdf::validate(&info.kdf)?;
                let keyset = AccountKeyset::unwrap(account_id, &auk, &info.wrapped_keyset)?;
                if keyset.sig_public().as_slice() != info.sig_pk || keyset.enc.public_bytes() != info.enc_pk {
                    return Err(internal("server account keys do not match the keyset"));
                }
                AccountRecord {
                    account_id,
                    kdf: info.kdf,
                    wrapped_keyset: info.wrapped_keyset,
                    enc_pk: info.enc_pk,
                    sig_pk: info.sig_pk,
                    primary_vault: Uuid::nil(), // chosen after the first sync
                }
            }
        };
        let keyset = AccountKeyset::unwrap(account_id, &auk, &acct.wrapped_keyset)?;
        let vault_key = self.open_vault_key(&keyset, acct.primary_vault)?;
        self.save_account(&acct)?;
        let mut inner = self.lock_inner();
        inner.account = Some(acct);
        inner.unlocked = Some(Unlocked {
            keyset: Arc::new(keyset),
            vault_key: Arc::new(vault_key),
            auth_input: Some(derived.auth_input),
        });
        Ok(LoginResult::Ok)
    }

    /// Pull, merge, push and verify every vault, renewing an expired session if possible.
    pub async fn sync_now(&self) -> Result<SyncReport> {
        if self.syncing.swap(true, Ordering::AcqRel) {
            return Err(CoreError::Busy);
        }
        let _guard = SyncGuard(&self.syncing);
        let api = self.api()?;
        let (_, u) = self.unlocked_snapshot()?;
        let device_id = api.signer().device_id();
        let store: &dyn Store = self.store.as_ref();
        let run = || async { SyncContext { api: &api, store, keyset: &u.keyset, device_id }.sync_all().await };
        let report = match run().await {
            Err(SyncError::NotAuthenticated) => {
                let auth = u.auth_input.clone().ok_or(CoreError::NotAuthenticated)?;
                if self.do_login(&api, u.keyset.account_id, auth.as_ref(), None).await? == LoginResult::PendingApproval
                {
                    return Err(CoreError::PendingApproval);
                }
                run().await?
            }
            other => other?,
        };
        self.after_sync()?;
        Ok(SyncReport {
            pulled: report.pulled,
            pushed: report.pushed,
            merged: report.merged,
            restored_item_ids: report.restored.iter().map(Uuid::to_string).collect(),
            vaults_synced: report.vaults_synced,
            vaults_skipped: report.vaults_skipped.len() as u32,
        })
    }

    pub async fn list_devices(&self) -> Result<Vec<DeviceDto>> {
        let devices = self.api()?.devices().await?;
        Ok(devices
            .into_iter()
            .map(|d| DeviceDto {
                device_id: d.device_id.to_string(),
                name: d.name,
                platform: platform_to_dto(d.platform),
                approved: d.approved,
                revoked: d.revoked_at.is_some(),
                current: d.current,
                created_at: d.created_at,
                key_fingerprint: device_key_fingerprint(&d.p256_pk),
            })
            .collect())
    }

    pub async fn approve_device(&self, device_id: &str) -> Result<()> {
        Ok(self.api()?.approve_device(parse_id(device_id)?).await?)
    }

    pub async fn revoke_device(&self, device_id: &str) -> Result<()> {
        Ok(self.api()?.revoke_device(parse_id(device_id)?).await?)
    }

    /// Ends the server session (local data stays).
    pub async fn logout(&self) -> Result<()> {
        let api = self.api()?;
        let r = api.logout().await;
        self.store.delete_meta(META_SESSION)?;
        match r {
            Ok(()) | Err(SyncError::NotAuthenticated) => Ok(()),
            Err(e) => Err(e.into()),
        }
    }

    pub fn is_logged_in(&self) -> bool {
        self.store.get_meta(META_SESSION).ok().flatten().is_some()
    }

    // ------------------------------------------------------------ internals

    fn unlocked_snapshot(&self) -> Result<(AccountRecord, Unlocked)> {
        let inner = self.lock_inner();
        let acct = inner.account.clone().ok_or(CoreError::NoAccount)?;
        let u = inner.unlocked.clone().ok_or(CoreError::Locked)?;
        Ok((acct, u))
    }

    fn save_account(&self, acct: &AccountRecord) -> Result<()> {
        Ok(self.store.put_meta(META_ACCOUNT, &serde_json::to_vec(acct).map_err(internal)?)?)
    }

    fn create_vault(&self, keyset: &AccountKeyset, vault_id: Uuid) -> Result<SymKey> {
        let (vault_key, sealed) = keyset.new_vault_key(vault_id)?;
        let meta = vault_key.seal(
            br#"{"name":"Personal"}"#,
            &Aad::build(ObjectType::VaultMeta, keyset.account_id, Some(vault_id), None),
        )?;
        self.store.put_vault(&VaultRow::new(vault_id, sealed, Some(meta)))?;
        Ok(vault_key)
    }

    fn open_vault_key(&self, keyset: &AccountKeyset, vault_id: Uuid) -> Result<SymKey> {
        if vault_id.is_nil() {
            // Enrolled but the first sync has not brought the vault yet.
            return Ok(SymKey::from_bytes(Uuid::nil(), [0; 32]));
        }
        let row = self.store.vault(vault_id)?.ok_or_else(|| internal("primary vault missing"))?;
        Ok(keyset.open_vault_key(vault_id, &row.sealed_key)?)
    }

    fn all_items(&self, acct: &AccountRecord, u: &Unlocked) -> Result<Vec<Item>> {
        let mut out = Vec::new();
        for li in self.store.list(acct.primary_vault)? {
            if let Some(item) = decrypt(acct, &u.vault_key, &li.record)? {
                out.push(item);
            }
        }
        Ok(out)
    }

    /// Seals and stores an item like kv-ffi does: next `seq`, previous version to history, queued
    /// for push. `bump` advances `modified_at` for edits that did not set it themselves.
    fn write_item(
        &self,
        acct: &AccountRecord,
        u: &Unlocked,
        model: &mut Item,
        existing: Option<LocalItem>,
        bump: bool,
    ) -> Result<()> {
        let vault = acct.primary_vault;
        let id = model.id;
        let now = now();
        if bump && existing.is_some() {
            model.modified_at = now.max(model.modified_at + 1);
        }
        model.seq = kv_sync::engine::next_local_version(self.store.as_ref(), acct.account_id, vault, &u.vault_key, id)?;
        let json = Zeroizing::new(serde_json::to_vec(model).map_err(internal)?);
        let sealed = seal_item(acct.account_id, vault, id, &u.vault_key, &json)?;
        if let Some(li) = existing.filter(|li| !li.record.deleted) {
            if let (Some(k), Some(p)) = (li.record.wrapped_item_key, li.record.payload) {
                self.store.push_history(
                    vault,
                    id,
                    &HistoryEntry { revision: li.record.revision, wrapped_item_key: k, payload: p, saved_at: now },
                )?;
            }
        }
        let device = self.device_id().unwrap_or(Uuid::nil());
        let record = ItemRecord {
            item_id: id,
            revision: 0,
            deleted: false,
            wrapped_item_key: Some(sealed.wrapped_item_key),
            payload: Some(sealed.payload),
            updated_by: device,
            updated_at: String::new(),
        };
        Ok(self.store.put_local(vault, &record)?)
    }

    fn enroll(&self) -> Result<DeviceEnroll> {
        let inner = self.lock_inner();
        let d = inner.device.as_ref().ok_or(CoreError::NotConfigured)?;
        Ok(DeviceEnroll {
            device_id: d.signer.device_id(),
            name: d.name.chars().take(64).collect(),
            platform: d.platform,
            p256_pk: d.signer.public_key(),
        })
    }

    fn api(&self) -> Result<Arc<ApiClient>> {
        let mut inner = self.lock_inner();
        if let Some(api) = &inner.api {
            return Ok(api.clone());
        }
        let server = inner.server.clone().ok_or(CoreError::NotConfigured)?;
        let signer = inner.device.as_ref().ok_or(CoreError::NotConfigured)?.signer.clone();
        let api = Arc::new(ApiClient::new(&ServerConfig::new(server.url, server.pins), signer)?);
        if let Some(s) = self.store.get_meta(META_SESSION)? {
            api.set_session(Some(String::from_utf8_lossy(&s).into_owned()));
        }
        inner.api = Some(api.clone());
        Ok(api)
    }

    async fn do_login(
        &self,
        api: &ApiClient,
        account_id: Uuid,
        auth_input: &[u8],
        totp: Option<String>,
    ) -> Result<LoginResult> {
        let device = self.enroll()?;
        match api.login(account_id, auth_input, device, totp).await? {
            LoginOutcome::Ok { session } => {
                self.store.put_meta(META_SESSION, session.as_bytes())?;
                Ok(LoginResult::Ok)
            }
            LoginOutcome::PendingApproval => Ok(LoginResult::PendingApproval),
        }
    }

    /// Persists a renewed session and picks the primary vault on a newly enrolled browser.
    fn after_sync(&self) -> Result<()> {
        let api_session = self.lock_inner().api.as_ref().and_then(|a| a.session());
        if let Some(s) = api_session {
            self.store.put_meta(META_SESSION, s.as_bytes())?;
        }
        let mut inner = self.lock_inner();
        let Some(mut acct) = inner.account.clone() else { return Ok(()) };
        if !acct.primary_vault.is_nil() {
            return Ok(());
        }
        let keyset = inner.unlocked.as_ref().ok_or(CoreError::Locked)?.keyset.clone();
        let vault_id = match self.store.vaults()?.first() {
            Some(v) => v.vault_id,
            None => {
                let id = Uuid::new_v4();
                self.create_vault(&keyset, id)?;
                id
            }
        };
        acct.primary_vault = vault_id;
        let vault_key = self.open_vault_key(&keyset, vault_id)?;
        self.save_account(&acct)?;
        inner.account = Some(acct);
        if let Some(u) = inner.unlocked.as_mut() {
            u.vault_key = Arc::new(vault_key);
        }
        Ok(())
    }
}

// ---------------------------------------------------------------- free functions

pub fn generate_password(length: u32, symbols: bool) -> String {
    generator::generate_password(&generator::PasswordOptions { length: length as usize, symbols, ..Default::default() })
}

pub fn totp_code(secret_or_uri: &str, unix_time: u64) -> Result<TotpCode> {
    let t = Totp::parse(secret_or_uri).map_err(|e| CoreError::Invalid { msg: e.to_string() })?;
    Ok(TotpCode { code: t.code_at(unix_time), seconds_remaining: t.remaining(unix_time), period: t.period })
}

pub fn match_url(item_url: &str, page_url: &str) -> MatchLevelDto {
    match matching::match_url(item_url, page_url) {
        matching::MatchLevel::None => MatchLevelDto::None,
        matching::MatchLevel::Domain => MatchLevelDto::Domain,
        matching::MatchLevel::Host => MatchLevelDto::Host,
        matching::MatchLevel::Exact => MatchLevelDto::Exact,
    }
}

/// `None` for tombstones.
pub fn decrypt(acct: &AccountRecord, vault_key: &SymKey, record: &ItemRecord) -> Result<Option<Item>> {
    let (Some(k), Some(p)) = (&record.wrapped_item_key, &record.payload) else { return Ok(None) };
    if record.deleted {
        return Ok(None);
    }
    let sealed = SealedItem { wrapped_item_key: k.clone(), payload: p.clone() };
    let pt = open_item(acct.account_id, acct.primary_vault, record.item_id, vault_key, &sealed)?;
    serde_json::from_slice(&pt).map(Some).map_err(internal)
}

fn parse_import(data: &[u8], format: ImportFormat) -> Result<kv_import::Parsed> {
    let format = match format {
        ImportFormat::OnePux => kv_import::Format::OnePux,
        ImportFormat::Csv => kv_import::Format::Csv,
        // `Format` wipes the passphrase on drop.
        ImportFormat::KestroveEncrypted { passphrase } => kv_import::Format::Encrypted { passphrase },
    };
    Ok(kv_import::parse(data, &format, now())?)
}

fn summary(i: &Item) -> ItemSummary {
    ItemSummary {
        id: i.id.to_string(),
        kind: kind_to_dto(i.kind),
        title: i.title.clone(),
        username: i.username.clone(),
        urls: i.urls.clone(),
        favorite: i.favorite,
        has_totp: i.totp.is_some(),
    }
}

fn passkey_summary(item: &Item, pk: &Passkey) -> PasskeySummary {
    PasskeySummary {
        item_id: item.id.to_string(),
        credential_id: pk.credential_id.clone(),
        rp_id: pk.rp_id.clone(),
        user_handle: pk.user_handle.clone(),
        user_name: pk.user_name.clone(),
        created_at: pk.created_at,
    }
}

pub fn to_dto(i: &Item) -> ItemDto {
    ItemDto {
        id: i.id.to_string(),
        kind: kind_to_dto(i.kind),
        title: i.title.clone(),
        username: i.username.clone(),
        password: i.password.clone(),
        urls: i.urls.clone(),
        totp: i.totp.clone(),
        notes: i.notes.clone(),
        favorite: i.favorite,
        tags: i.tags.clone(),
        modified_at: i.modified_at,
    }
}

fn kind_to_dto(k: ItemKind) -> ItemKindDto {
    match k {
        ItemKind::Login => ItemKindDto::Login,
        ItemKind::SecureNote => ItemKindDto::SecureNote,
        ItemKind::Card => ItemKindDto::Card,
        ItemKind::Identity => ItemKindDto::Identity,
    }
}

fn kind_from_dto(k: ItemKindDto) -> ItemKind {
    match k {
        ItemKindDto::Login => ItemKind::Login,
        ItemKindDto::SecureNote => ItemKind::SecureNote,
        ItemKindDto::Card => ItemKind::Card,
        ItemKindDto::Identity => ItemKind::Identity,
    }
}

fn platform_to_dto(p: Platform) -> PlatformDto {
    match p {
        Platform::Ios => PlatformDto::Ios,
        Platform::Macos => PlatformDto::Macos,
        Platform::Android => PlatformDto::Android,
        Platform::Windows => PlatformDto::Windows,
        Platform::Linux => PlatformDto::Linux,
    }
}

/// Hex of the first 16 bytes of SHA-256(P-256 public key), as kv-ffi shows it.
pub fn device_key_fingerprint(p256_pk: &[u8]) -> String {
    use sha2::{Digest, Sha256};
    Sha256::digest(p256_pk)[..16].iter().map(|b| format!("{b:02x}")).collect()
}

fn parse_id(s: &str) -> Result<Uuid> {
    Uuid::parse_str(s).map_err(|_| CoreError::Invalid { msg: "id must be a UUID".into() })
}