//! The install screen's state and file work, shared by every wayBetter app: links waiting for the
//! shell, installs staged for the confirmation screen, the verified catalog (and its offline copy),
//! and where installed things came from. The app wraps these methods in shell-only Tauri commands
//! and passes a function that runs a plugin start/stop script in its site tabs.

use super::catalog::{
    self as dist, Catalog, CatalogItem, InstallLink, InstallRecord, InstallRecords, Kind, SourceKind, StoreConfig, ThemeInfo,
};
use super::strings::{self as packs, StringsInfo, StringsList, StringsStore};
use crate::plugins::{self, PluginHost, PluginStore, ScriptPlugin, PLUGIN_SUFFIX};
use serde::{Deserialize, Serialize};
use std::collections::{BTreeMap, HashMap, VecDeque};
use std::path::{Path, PathBuf};
use std::sync::{Mutex, MutexGuard};
use std::time::{Duration, Instant};
use url::Url;

/// Install records in the app-data folder.
pub const RECORDS_FILE: &str = "store-installed.json";
/// The last verified catalog and its signature (verified again when read back).
pub const CATALOG_CACHE: &str = "store-catalog.json";
pub const CATALOG_SIG_CACHE: &str = "store-catalog.json.sig";
/// Shell event: a validated install link (`{ link: { kind, url } }`), a "Share my setup" link
/// (`{ setup }`: its text, for the shell's preview) or `{ error }`.
pub const EVENT_LINK: &str = "install-link";
/// "Share my setup" links: `waybetter://setup?app=…&d=…`. Native code only checks the shape and
/// hands the text to the shell; it never decodes or applies a setup (the shell shows what would
/// change and asks first).
pub const SETUP_LINK: &str = "waybetter://setup";
const MAX_SETUP_LINK: usize = 24 * 1024;
/// Links received before the shell asked for them (startup, or while the shell reloads).
const MAX_PENDING: usize = 8;
const MAX_STAGED: usize = 8;
const STAGED_TTL: Duration = Duration::from_secs(15 * 60);
/// The confirmation screen enables Install after a moment; a commit faster than this was not read.
pub const MIN_REVIEW: Duration = Duration::from_millis(600);
/// How long a fetched catalog is used before the next store open fetches it again.
pub const CATALOG_TTL: Duration = Duration::from_secs(10 * 60);

#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct LinkEvent {
    #[serde(skip_serializing_if = "Option::is_none")]
    pub link: Option<InstallLink>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub error: Option<String>,
    /// A "Share my setup" link, as text (see [`SETUP_LINK`]).
    #[serde(skip_serializing_if = "Option::is_none")]
    pub setup: Option<String>,
}

/// `Some` when `raw` is a setup link: its text when it has the plain shape (the path, a query of
/// URL-safe characters, bounded), else an error. `None`: not a setup link.
pub fn setup_link(raw: &str) -> Option<Result<String, String>> {
    let rest = raw.strip_prefix(SETUP_LINK)?;
    let query = rest.strip_prefix("/?").or_else(|| rest.strip_prefix('?'));
    let ok = query.is_some_and(|query| {
        !query.is_empty()
            && raw.len() <= MAX_SETUP_LINK
            && query.bytes().all(|b| b.is_ascii_alphanumeric() || matches!(b, b'-' | b'_' | b'=' | b'&' | b'%' | b'.'))
    });
    Some(if ok { Ok(raw.to_owned()) } else { Err("LINK: this setup link is not valid".to_owned()) })
}

#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct SourceView {
    pub kind: SourceKind,
    pub url: Option<String>,
    /// "wayBetter Store (signed catalog, sha256 verified)", "Link: waybetter.fyi", "A file you dropped"
    pub label: String,
    pub signed: bool,
}

#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct Existing {
    pub version: String,
    pub enabled: bool,
    /// The installed file is byte-identical to this one.
    pub same: bool,
}

/// Everything the confirmation screen shows. `text` is the exact content that will be written.
#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct InstallPreview {
    pub token: String,
    pub kind: Kind,
    pub source: SourceView,
    pub sha256: String,
    pub size: usize,
    pub file: Option<String>,
    pub text: String,
    pub version: String,
    pub plugin: Option<ScriptPlugin>,
    pub theme: Option<ThemeInfo>,
    /// String packs: what the pack says about itself (the shell adds coverage from the inventory).
    pub strings: Option<StringsInfo>,
    pub findings: Vec<&'static str>,
    pub existing: Option<Existing>,
    pub store: Option<CatalogItem>,
}

#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct InstallOutcome {
    pub kind: Kind,
    /// Plugins: the list after installing.
    pub plugins: Option<Vec<ScriptPlugin>>,
    /// Themes: the exact JSON the owner confirmed; the shell adds it (sanitized) to its themes.
    pub theme_text: Option<String>,
    /// String packs: the installed packs after installing.
    pub strings: Option<StringsList>,
}

#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct InstalledPlugin {
    pub version: String,
    pub sha256: String,
    pub enabled: bool,
}

/// What the Store view shows: this app's items from the verified catalog, with what is installed.
#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct StoreView {
    pub catalog: Option<Catalog>,
    pub fetched_at: Option<String>,
    /// Why the live catalog could not be loaded (a cached copy may still be shown).
    pub error: Option<String>,
    /// Installed plugin files the catalog lists, by file name.
    pub plugins: BTreeMap<String, InstalledPlugin>,
    pub records: InstallRecords,
}

/// A store item the shell asks for (`store_stage`).
#[derive(Clone, Debug, Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct StoreItemRef {
    pub kind: String,
    pub id: String,
}

struct Staged {
    kind: Kind,
    file: Option<String>,
    bytes: Vec<u8>,
    sha256: String,
    source: SourceKind,
    url: Option<String>,
    store: Option<CatalogItem>,
    version: String,
    created: Instant,
}

struct CatalogCache {
    catalog: Catalog,
    fetched: Instant,
    fetched_at: String,
}

struct Inner {
    pending: VecDeque<LinkEvent>,
    staged: HashMap<String, Staged>,
    catalog: Option<CatalogCache>,
    records: InstallRecords,
}

/// One app's store and install state. Create it once (`Store::new`) and keep it in app state.
pub struct Store {
    config: &'static StoreConfig,
    plugins: &'static PluginHost,
    data_dir: PathBuf,
    inner: Mutex<Inner>,
}

fn new_token() -> String {
    let mut bytes = [0u8; 16];
    let _ = getrandom::getrandom(&mut bytes);
    bytes.iter().map(|b| format!("{b:02x}")).collect()
}

pub fn now_rfc3339() -> String {
    chrono::Utc::now().to_rfc3339_opts(chrono::SecondsFormat::Secs, true)
}

fn valid_theme_id(id: &str) -> bool {
    !id.is_empty() && id.len() <= 40 && id.bytes().all(|b| b.is_ascii_lowercase() || b.is_ascii_digit() || b == b'-')
}

impl Store {
    /// `data_dir` is the app-data folder: install records and the catalog copy live in it, and
    /// plugins in its `plugins` folder (the same folder the app's `PluginStore` uses).
    pub fn new(config: &'static StoreConfig, plugins: &'static PluginHost, data_dir: PathBuf) -> Self {
        let records = std::fs::read_to_string(data_dir.join(RECORDS_FILE))
            .ok()
            .and_then(|raw| serde_json::from_str::<InstallRecords>(&raw).ok())
            .unwrap_or_default();
        Self {
            config,
            plugins,
            data_dir,
            inner: Mutex::new(Inner { pending: VecDeque::new(), staged: HashMap::new(), catalog: None, records }),
        }
    }

    pub fn config(&self) -> &'static StoreConfig {
        self.config
    }

    fn lock(&self) -> MutexGuard<'_, Inner> {
        self.inner.lock().unwrap_or_else(|poisoned| poisoned.into_inner())
    }

    fn plugin_store(&self) -> PluginStore {
        PluginStore::new(self.data_dir.join("plugins"), self.plugins)
    }

    /// The installed string packs (`<data>/strings`).
    pub fn strings(&self) -> StringsStore {
        StringsStore::new(&self.data_dir)
    }

    fn plugins_dir(&self) -> PathBuf {
        self.data_dir.join("plugins")
    }

    fn save_records(&self, records: &InstallRecords) {
        let result = serde_json::to_string_pretty(records)
            .map_err(|_| "STORAGE: serialization failed".to_owned())
            .and_then(|json| std::fs::write(self.data_dir.join(RECORDS_FILE), json).map_err(|error| format!("STORAGE: {error}")));
        if let Err(error) = result {
            eprintln!("{}: {error}", self.config.product);
        }
    }

    // -----------------------------------------------------------------------------------------
    // Links

    /// A link reached the app (OS deep link, second launch): validate it and queue it for the
    /// shell. Returns the event to emit ([`EVENT_LINK`]). Nothing is downloaded or installed here.
    pub fn receive_link(&self, raw: &str) -> LinkEvent {
        let event = match setup_link(raw) {
            Some(Ok(text)) => LinkEvent { link: None, error: None, setup: Some(text) },
            Some(Err(error)) => LinkEvent { link: None, error: Some(error), setup: None },
            None => match dist::parse_install_link(self.config, raw) {
                Ok(link) => LinkEvent { link: Some(link), error: None, setup: None },
                Err(error) => LinkEvent { link: None, error: Some(error), setup: None },
            },
        };
        let mut inner = self.lock();
        if inner.pending.len() >= MAX_PENDING {
            inner.pending.pop_front();
        }
        inner.pending.push_back(event.clone());
        event
    }

    /// Links that arrived before the shell listened (drained).
    pub fn take_pending(&self) -> Vec<LinkEvent> {
        self.lock().pending.drain(..).collect()
    }

    /// The same rules as a link the OS handed over, for a `kind` + `url` the shell asks for: the
    /// shell cannot widen them. Returns the link and, for plugins, the file name.
    pub fn check_link(&self, kind: &str, url: &str) -> Result<(InstallLink, Option<String>), String> {
        let kind = Kind::parse(kind)?;
        let link = dist::parse_install_link(self.config, &dist::install_link(self.config, kind, url))?;
        let file = match kind {
            Kind::Plugin => Some(dist::plugin_file_from_url(&Url::parse(&link.url).map_err(|_| "VALIDATION: invalid URL")?)?),
            Kind::Theme | Kind::Strings => None,
        };
        Ok((link, file))
    }

    // -----------------------------------------------------------------------------------------
    // Staging

    /// Validates bytes for `kind` and stages them under a fresh token.
    fn stage(&self, kind: Kind, file: Option<String>, bytes: Vec<u8>, source: SourceKind, url: Option<String>, store: Option<CatalogItem>) -> Result<InstallPreview, String> {
        let mut inner = self.lock();
        inner.staged.retain(|_, staged| staged.created.elapsed() < STAGED_TTL);
        while inner.staged.len() >= MAX_STAGED {
            let oldest = inner.staged.iter().min_by_key(|(_, s)| s.created).map(|(k, _)| k.clone());
            match oldest {
                Some(key) => inner.staged.remove(&key),
                None => break,
            };
        }
        let text = String::from_utf8(bytes.clone()).map_err(|_| "VALIDATION: not UTF-8 text")?;
        let mut strings = None;
        let (plugin, theme, findings, version, existing) = match kind {
            Kind::Plugin => {
                let file = file.as_deref().ok_or("VALIDATION: missing plugin file name")?;
                let validated = dist::validate_plugin(file, &bytes)?;
                let local = self.plugin_store();
                let existing = local.file_hash(file).map(|hash| Existing {
                    version: plugins::parse_meta(file, &std::fs::read_to_string(self.plugins_dir().join(file)).unwrap_or_default()).version,
                    enabled: local.is_enabled(file),
                    same: hash == validated.sha256,
                });
                let version = validated.meta.version.clone();
                (Some(validated.meta), None, validated.findings, version, existing)
            }
            Kind::Strings => {
                let info = packs::validate_strings(&bytes)?;
                if info.site != self.config.app_id {
                    return Err(format!("VALIDATION: this string pack is for another app ({})", info.site));
                }
                let id = packs::pack_id(&info, store.as_ref().map(|item| item.id.as_str()));
                let local = self.strings();
                let existing = local.read(&id).map(|old| Existing {
                    version: packs::validate_strings(&old).map(|old| old.version).unwrap_or_default(),
                    enabled: local.state().enabled.contains(&id),
                    same: dist::sha256_hex(&old) == dist::sha256_hex(&bytes),
                });
                let version = if info.version.is_empty() { store.as_ref().map(|item| item.version.clone()).unwrap_or_default() } else { info.version.clone() };
                strings = Some(info);
                (None, None, Vec::new(), version, existing)
            }
            Kind::Theme => {
                let info = dist::validate_theme(&bytes)?;
                let version = store.as_ref().map(|item| item.version.clone()).unwrap_or_default();
                (None, Some(info), Vec::new(), version, None)
            }
        };
        let label = match source {
            SourceKind::Store => "wayBetter Store (signed catalog, sha256 verified)".to_owned(),
            SourceKind::Link => format!("Link: {}", url.as_deref().and_then(|u| Url::parse(u).ok()).and_then(|u| u.host_str().map(str::to_owned)).unwrap_or_default()),
            SourceKind::File => "A file you dropped".to_owned(),
        };
        let sha256 = dist::sha256_hex(&bytes);
        let token = new_token();
        let preview = InstallPreview {
            token: token.clone(),
            kind,
            source: SourceView { kind: source.clone(), url: url.clone(), label, signed: source == SourceKind::Store },
            sha256: sha256.clone(),
            size: bytes.len(),
            file: file.clone(),
            text,
            version: version.clone(),
            plugin,
            theme,
            strings,
            findings,
            existing,
            store: store.clone(),
        };
        inner.staged.insert(token, Staged { kind, file, bytes, sha256, source, url, store, version, created: Instant::now() });
        Ok(preview)
    }

    /// Stages what a link (checked with [`Self::check_link`]) downloaded. A link to a file the
    /// signed store lists is still a link (no store badge), but the preview carries the store entry
    /// when the hash matches so the screen can say so.
    pub fn stage_link_download(&self, link: &InstallLink, file: Option<String>, bytes: Vec<u8>) -> Result<InstallPreview, String> {
        if bytes.len() > link.kind.max_bytes() {
            return Err("VALIDATION: the file is larger than allowed".into());
        }
        let hash = dist::sha256_hex(&bytes);
        let store = self.lock().catalog.as_ref().and_then(|cache| cache.catalog.items.iter().find(|item| item.url == link.url && item.sha256 == hash).cloned());
        self.stage(link.kind, file, bytes, SourceKind::Link, Some(link.url.clone()), store)
    }

    /// A file dropped on the window (the shell read it with the File API; validated here).
    pub fn stage_file(&self, name: &str, text: String) -> Result<InstallPreview, String> {
        let lower = name.to_ascii_lowercase();
        let (kind, file) = if lower.ends_with(PLUGIN_SUFFIX) {
            (Kind::Plugin, Some(name.to_owned()))
        } else if lower.ends_with(".strings.json") {
            (Kind::Strings, None)
        } else if lower.ends_with(".json") {
            (Kind::Theme, None)
        } else {
            return Err("VALIDATION: drop a theme (.json), a plugin (.plugin.js) or a string pack (.strings.json)".into());
        };
        if text.len() > kind.max_bytes() {
            return Err("VALIDATION: the file is larger than allowed".into());
        }
        self.stage(kind, file, text.into_bytes(), SourceKind::File, None, None)
    }

    /// The catalog entry the shell asks for (this app's items only).
    pub fn catalog_item(&self, item: &StoreItemRef) -> Result<CatalogItem, String> {
        let kind = Kind::parse(&item.kind)?;
        self.lock()
            .catalog
            .as_ref()
            .and_then(|cache| cache.catalog.items.iter().find(|i| i.kind == kind && i.id == item.id).cloned())
            .ok_or_else(|| "STORE: not in the catalog; refresh the store".into())
    }

    /// Stages a downloaded store item after checking it against the signed catalog (size + sha256).
    pub fn stage_store_download(&self, entry: CatalogItem, bytes: Vec<u8>) -> Result<InstallPreview, String> {
        dist::verify_item(&entry, &bytes)?;
        if !entry.is_for(self.config.app_id) {
            return Err("STORE: this item is for another app".into());
        }
        self.stage(entry.kind, entry.file.clone(), bytes, SourceKind::Store, Some(entry.url.clone()), Some(entry))
    }

    pub fn cancel(&self, token: &str) {
        self.lock().staged.remove(token);
    }

    // -----------------------------------------------------------------------------------------
    // Commit and remove

    /// The owner confirmed the screen for `token`. Plugins are written (validated again) and, when
    /// `enable` (or they were enabled before an update), started: `run` evaluates each start/stop
    /// script in the app's site tabs. Themes are handed back for the shell to add under `theme_id`.
    pub fn commit(&self, token: &str, enable: bool, theme_id: Option<String>, run: impl Fn(&str)) -> Result<InstallOutcome, String> {
        let mut inner = self.lock();
        let Some(staged) = inner.staged.get(token) else {
            return Err("INSTALL: this install screen expired; open it again".into());
        };
        if staged.created.elapsed() < MIN_REVIEW {
            return Err("INSTALL: confirm again after reviewing".into());
        }
        let staged = inner.staged.remove(token).expect("present");
        let record = |version: String| InstallRecord {
            kind: staged.kind,
            source: staged.source.clone(),
            url: staged.url.clone(),
            store_id: staged.store.as_ref().map(|item| item.id.clone()),
            version,
            sha256: staged.sha256.clone(),
            installed_at: now_rfc3339(),
        };
        match staged.kind {
            Kind::Plugin => {
                let file = staged.file.clone().ok_or("INSTALL: missing file")?;
                let store = self.plugin_store();
                let was_enabled = store.is_enabled(&file);
                let validated = store.install(&file, &staged.bytes)?;
                inner.records.insert(InstallRecords::key(Kind::Plugin, &file), record(validated.meta.version.clone()));
                let records = inner.records.clone();
                drop(inner);
                self.save_records(&records);
                if was_enabled {
                    // An update of a running plugin: stop the old code, start the new.
                    run(&plugins::stop_script(self.plugins, &file)?);
                    run(&store.start_script(&file)?);
                } else if enable {
                    let script = store.start_script(&file)?;
                    store.set_enabled(&file, true)?;
                    run(&script);
                }
                Ok(InstallOutcome { kind: Kind::Plugin, plugins: Some(store.list()?), theme_text: None, strings: None })
            }
            Kind::Strings => {
                let info = packs::validate_strings(&staged.bytes)?;
                let id = packs::pack_id(&info, staged.store.as_ref().map(|item| item.id.as_str()));
                let local = self.strings();
                local.install(&id, &staged.bytes, enable)?;
                inner.records.insert(InstallRecords::key(Kind::Strings, &id), record(staged.version.clone()));
                let records = inner.records.clone();
                drop(inner);
                self.save_records(&records);
                Ok(InstallOutcome { kind: Kind::Strings, plugins: None, theme_text: None, strings: Some(local.list()) })
            }
            Kind::Theme => {
                let id = theme_id.filter(|id| valid_theme_id(id)).ok_or("VALIDATION: invalid theme id")?;
                inner.records.insert(InstallRecords::key(Kind::Theme, &id), record(staged.version.clone()));
                let records = inner.records.clone();
                drop(inner);
                self.save_records(&records);
                let text = String::from_utf8(staged.bytes).map_err(|_| "VALIDATION: not UTF-8")?;
                Ok(InstallOutcome { kind: Kind::Theme, plugins: None, theme_text: Some(text), strings: None })
            }
        }
    }

    /// Deletes a plugin; `run` stops it in every site tab first.
    pub fn remove_plugin(&self, file: &str, run: impl Fn(&str)) -> Result<Vec<ScriptPlugin>, String> {
        let mut inner = self.lock();
        let store = self.plugin_store();
        let script = plugins::stop_script(self.plugins, file)?;
        store.remove(file)?;
        inner.records.items.remove(&InstallRecords::key(Kind::Plugin, file));
        let records = inner.records.clone();
        drop(inner);
        self.save_records(&records);
        run(&script);
        store.list()
    }

    /// Removes an installed string pack and forgets where it came from.
    pub fn remove_strings(&self, id: &str) -> Result<StringsList, String> {
        let local = self.strings();
        local.remove(id)?;
        let mut inner = self.lock();
        if inner.records.items.remove(&InstallRecords::key(Kind::Strings, id)).is_some() {
            let records = inner.records.clone();
            drop(inner);
            self.save_records(&records);
        }
        Ok(local.list())
    }

    /// Where installed plugins and themes came from (for badges and update checks).
    pub fn records(&self) -> InstallRecords {
        self.lock().records.clone()
    }

    /// A theme (or plugin) was removed elsewhere: forget where it came from.
    pub fn forget(&self, kind: &str, name: &str) -> Result<(), String> {
        let kind = Kind::parse(kind)?;
        let mut inner = self.lock();
        if inner.records.items.remove(&InstallRecords::key(kind, name)).is_some() {
            let records = inner.records.clone();
            drop(inner);
            self.save_records(&records);
        }
        Ok(())
    }

    // -----------------------------------------------------------------------------------------
    // Catalog

    /// Whether the catalog in memory is recent enough to show without fetching.
    pub fn catalog_is_fresh(&self) -> bool {
        self.lock().catalog.as_ref().is_some_and(|cache| cache.fetched.elapsed() < CATALOG_TTL)
    }

    /// Verifies fetched catalog bytes, keeps this app's part and saves the verified bytes for
    /// offline use (they are verified again when read back).
    pub fn accept_catalog(&self, body: &[u8], signature: &str) -> Result<(), String> {
        let catalog = dist::verify_catalog(self.config, body, signature)?;
        let _ = std::fs::write(self.data_dir.join(CATALOG_CACHE), body);
        let _ = std::fs::write(self.data_dir.join(CATALOG_SIG_CACHE), signature.as_bytes());
        self.lock().catalog = Some(CatalogCache { catalog, fetched: Instant::now(), fetched_at: now_rfc3339() });
        Ok(())
    }

    /// The live catalog could not be loaded: fall back to the saved copy (if it still verifies)
    /// when nothing is in memory. It is shown, but fetched again on the next open.
    pub fn use_cached_catalog(&self) {
        if self.lock().catalog.is_some() {
            return;
        }
        let Some((catalog, fetched_at)) = cached_catalog(self.config, &self.data_dir) else { return };
        let fetched = Instant::now().checked_sub(CATALOG_TTL).unwrap_or_else(Instant::now);
        let mut inner = self.lock();
        if inner.catalog.is_none() {
            inner.catalog = Some(CatalogCache { catalog, fetched, fetched_at });
        }
    }

    /// What the Store view shows, with `error` when the live catalog could not be loaded.
    pub fn view(&self, error: Option<String>) -> StoreView {
        let inner = self.lock();
        let local = self.plugin_store();
        let mut installed = BTreeMap::new();
        if let Some(cache) = &inner.catalog {
            for item in cache.catalog.items.iter().filter(|item| item.kind == Kind::Plugin) {
                let Some(file) = item.file.as_deref() else { continue };
                let Some(sha256) = local.file_hash(file) else { continue };
                let source = std::fs::read_to_string(self.plugins_dir().join(file)).unwrap_or_default();
                installed.insert(file.to_owned(), InstalledPlugin { version: plugins::parse_meta(file, &source).version, sha256, enabled: local.is_enabled(file) });
            }
        }
        StoreView {
            catalog: inner.catalog.as_ref().map(|cache| cache.catalog.clone()),
            fetched_at: inner.catalog.as_ref().map(|cache| cache.fetched_at.clone()),
            error,
            plugins: installed,
            records: inner.records.clone(),
        }
    }
}

fn cached_catalog(config: &StoreConfig, dir: &Path) -> Option<(Catalog, String)> {
    let body = std::fs::read(dir.join(CATALOG_CACHE)).ok()?;
    let signature = std::fs::read_to_string(dir.join(CATALOG_SIG_CACHE)).ok()?;
    let modified = std::fs::metadata(dir.join(CATALOG_CACHE)).and_then(|m| m.modified()).ok()?;
    let catalog = dist::verify_catalog(config, &body, &signature).ok()?;
    let at = chrono::DateTime::<chrono::Utc>::from(modified).to_rfc3339_opts(chrono::SecondsFormat::Secs, true);
    Some((catalog, at))
}

#[cfg(test)]
mod tests {
    use super::super::catalog::tests::{catalog_json, config, plugin_item, sign, test_key, theme_item, PLUGIN};
    use super::*;
    use std::cell::RefCell;

    static HOST: PluginHost = PluginHost {
        runtime_global: "WayBetterTest",
        origin: "https://example.com",
        product: "wayBetter test",
        css_element_id: "wb-test-css",
        example: None,
        bundled: &[],
        superseded: &[],
    };

    const THEME: &[u8] = br#"{"name":"Nord","author":"me","css":"a{}"}"#;

    fn store_with_catalog() -> (tempfile::TempDir, Store, Vec<u8>, String) {
        let dir = tempfile::tempdir().unwrap();
        let (key, public) = test_key(7);
        let mut kick = plugin_item(PLUGIN);
        kick["apps"] = serde_json::json!(["kick"]);
        kick["id"] = serde_json::json!("kick-tool");
        kick["file"] = serde_json::json!("kick-tool.plugin.js");
        let body = catalog_json(serde_json::json!([plugin_item(PLUGIN), theme_item(THEME), kick]));
        let signature = sign(&key, &body);
        let store = Store::new(config("x", &[public]), &HOST, dir.path().to_path_buf());
        (dir, store, body, signature)
    }

    fn reviewed() {
        std::thread::sleep(MIN_REVIEW + Duration::from_millis(50));
    }

    #[test]
    fn links_are_validated_and_queued_for_the_shell() {
        let (_dir, store, _, _) = store_with_catalog();
        let ok = store.receive_link("waybetter://install?kind=theme&url=https://waybetter.fyi/store/themes/nord.json");
        assert!(ok.link.is_some() && ok.error.is_none());
        let bad = store.receive_link("waybetter://install?kind=theme&url=https://evil.example/a.json");
        assert!(bad.link.is_none() && bad.error.unwrap().starts_with("LINK:"));
        // A "Share my setup" link is only handed over as text; its data is never read here.
        let setup = store.receive_link("waybetter://setup?app=x&d=eyJmb3JtYXQiOiJ3YXliZXR0ZXItc2V0dXAifQ");
        assert_eq!(setup.setup.as_deref(), Some("waybetter://setup?app=x&d=eyJmb3JtYXQiOiJ3YXliZXR0ZXItc2V0dXAifQ"));
        assert!(setup.link.is_none() && setup.error.is_none());
        for bad in ["waybetter://setup", "waybetter://setup?", "waybetter://setup?d=<script>", "waybetter://setup?d=a b", "waybetter://setupx?d=a"] {
            let event = store.receive_link(bad);
            assert!(event.setup.is_none(), "{bad}");
            assert!(event.error.is_some(), "{bad}");
        }
        let long = format!("waybetter://setup?d={}", "a".repeat(MAX_SETUP_LINK));
        assert!(store.receive_link(&long).setup.is_none(), "bounded");
        assert_eq!(serde_json::to_string(&setup).unwrap(), r#"{"setup":"waybetter://setup?app=x&d=eyJmb3JtYXQiOiJ3YXliZXR0ZXItc2V0dXAifQ"}"#);
        store.take_pending();
        for _ in 0..20 {
            store.receive_link("waybetter://install?kind=theme&url=https://waybetter.fyi/a.json");
        }
        assert_eq!(store.take_pending().len(), MAX_PENDING, "bounded");
        assert!(store.take_pending().is_empty(), "drained");
        // The shell's kind + url go through the same parser.
        assert_eq!(store.check_link("plugin", "https://waybetter.fyi/store/plugins/tool.plugin.js").unwrap().1.as_deref(), Some("tool.plugin.js"));
        assert!(store.check_link("plugin", "https://waybetter.fyi/store/plugins/tool.js").is_err());
        assert!(store.check_link("theme", "https://evil.example/a.json").is_err());
        assert!(store.check_link("script", "https://waybetter.fyi/a.json").is_err());
    }

    #[test]
    fn the_catalog_is_verified_filtered_to_the_app_and_kept_for_offline_use() {
        let (dir, store, body, signature) = store_with_catalog();
        assert!(store.view(None).catalog.is_none());
        assert!(store.accept_catalog(&body, "AAAA").is_err());
        assert!(store.view(None).catalog.is_none(), "a bad signature changes nothing");
        store.accept_catalog(&body, &signature).unwrap();
        assert!(store.catalog_is_fresh());
        let view = store.view(None);
        let ids: Vec<_> = view.catalog.unwrap().items.iter().map(|i| i.id.clone()).collect();
        assert_eq!(ids, ["tool", "nord"], "the other app's item is not shown");
        assert!(store.catalog_item(&StoreItemRef { kind: "plugin".into(), id: "kick-tool".into() }).is_err(), "nor staged");
        // A fresh start offline: the saved copy verifies and is shown, marked stale.
        let again = Store::new(store.config(), &HOST, dir.path().to_path_buf());
        again.use_cached_catalog();
        assert_eq!(again.view(Some("NETWORK: offline".into())).catalog.unwrap().items.len(), 2);
        assert!(!again.catalog_is_fresh());
        // A tampered copy on disk is ignored.
        std::fs::write(dir.path().join(CATALOG_CACHE), [&body[..], b" "].concat()).unwrap();
        let tampered = Store::new(store.config(), &HOST, dir.path().to_path_buf());
        tampered.use_cached_catalog();
        assert!(tampered.view(None).catalog.is_none());
    }

    #[test]
    fn store_items_must_match_the_signed_catalog_and_install_the_staged_bytes() {
        let (dir, store, body, signature) = store_with_catalog();
        store.accept_catalog(&body, &signature).unwrap();
        let entry = store.catalog_item(&StoreItemRef { kind: "plugin".into(), id: "tool".into() }).unwrap();
        assert!(store.stage_store_download(entry.clone(), b"tampered".to_vec()).is_err());
        let preview = store.stage_store_download(entry, PLUGIN.to_vec()).unwrap();
        assert!(preview.source.signed && preview.existing.is_none());
        assert_eq!(preview.plugin.as_ref().unwrap().permissions.as_deref(), Some(&["ui".to_owned()][..]));
        // Too fast: the screen was not read.
        assert!(store.commit(&preview.token, true, None, |_| {}).unwrap_err().contains("reviewing"));
        reviewed();
        let ran = RefCell::new(Vec::new());
        let outcome = store.commit(&preview.token, true, None, |script| ran.borrow_mut().push(script.to_owned())).unwrap();
        assert_eq!(outcome.plugins.unwrap().iter().filter(|p| p.file == "tool.plugin.js" && p.enabled).count(), 1);
        assert_eq!(ran.borrow().len(), 1, "started once");
        assert_eq!(std::fs::read(dir.path().join("plugins/tool.plugin.js")).unwrap(), PLUGIN);
        let record = &store.records().items["plugin:tool.plugin.js"];
        assert_eq!((record.source.clone(), record.store_id.as_deref(), record.version.as_str()), (SourceKind::Store, Some("tool"), "1.0.0"));
        // The token is single use; records survive a restart.
        assert!(store.commit(&preview.token, true, None, |_| {}).unwrap_err().contains("expired"));
        assert_eq!(Store::new(store.config(), &HOST, dir.path().to_path_buf()).records(), store.records());
        // Installed and identical: the view says so.
        assert_eq!(store.view(None).plugins["tool.plugin.js"].sha256, dist::sha256_hex(PLUGIN));
        // Staging it again shows what is installed; committing an update of a running plugin stops then starts it.
        let entry = store.catalog_item(&StoreItemRef { kind: "plugin".into(), id: "tool".into() }).unwrap();
        let again = store.stage_store_download(entry, PLUGIN.to_vec()).unwrap();
        let existing = again.existing.unwrap();
        assert!(existing.same && existing.enabled);
        reviewed();
        let ran = RefCell::new(Vec::new());
        store.commit(&again.token, false, None, |script| ran.borrow_mut().push(script.to_owned())).unwrap();
        assert_eq!(ran.borrow().len(), 2, "stop + start");
        // Remove: stopped, deleted, forgotten.
        let ran = RefCell::new(0);
        let list = store.remove_plugin("tool.plugin.js", |_| *ran.borrow_mut() += 1).unwrap();
        assert!(list.iter().all(|p| p.file != "tool.plugin.js") && *ran.borrow() == 1);
        assert!(!store.records().items.contains_key("plugin:tool.plugin.js"));
    }

    #[test]
    fn dropped_files_and_links_are_validated_and_themes_come_back_as_text() {
        let (_dir, store, body, signature) = store_with_catalog();
        assert!(store.stage_file("photo.png", "x".into()).is_err());
        assert!(store.stage_file("bad.plugin.js", "module.exports = 1".into()).unwrap_err().contains("header"));
        assert!(store.stage_file("big.json", "a".repeat(dist::MAX_THEME_BYTES + 1)).unwrap_err().contains("larger"));
        let dropped = store.stage_file("nord.json", String::from_utf8(THEME.to_vec()).unwrap()).unwrap();
        assert!(!dropped.source.signed && dropped.theme.as_ref().unwrap().name == "Nord");
        reviewed();
        assert!(store.commit(&dropped.token, true, Some("../x".into()), |_| {}).unwrap_err().contains("theme id"));
        let dropped = store.stage_file("nord.json", String::from_utf8(THEME.to_vec()).unwrap()).unwrap();
        reviewed();
        let outcome = store.commit(&dropped.token, true, Some("nord-2".into()), |_| panic!("themes run nothing")).unwrap();
        assert_eq!(outcome.theme_text.as_deref().map(str::as_bytes), Some(THEME));
        assert_eq!(store.records().items["theme:nord-2"].source, SourceKind::File);
        store.forget("theme", "nord-2").unwrap();
        assert!(store.records().items.is_empty());
        // A link to a file the signed store lists carries the store entry, but is still a link.
        store.accept_catalog(&body, &signature).unwrap();
        let (link, file) = store.check_link("theme", "https://waybetter.fyi/store/themes/nord.json").unwrap();
        let preview = store.stage_link_download(&link, file, THEME.to_vec()).unwrap();
        assert!(!preview.source.signed && preview.store.is_some() && preview.source.label == "Link: waybetter.fyi");
        let other = store.stage_link_download(&link, None, br#"{"name":"Other"}"#.to_vec()).unwrap();
        assert!(other.store.is_none(), "different bytes: no store entry");
        store.cancel(&other.token);
        assert!(store.commit(&other.token, true, Some("other".into()), |_| {}).is_err());
    }

    #[test]
    fn staging_is_bounded() {
        let (_dir, store, _, _) = store_with_catalog();
        let tokens: Vec<String> = (0..MAX_STAGED + 4)
            .map(|_| {
                std::thread::sleep(Duration::from_millis(2));
                store.stage_file("a.json", r#"{"name":"A"}"#.into()).unwrap().token
            })
            .collect();
        assert_eq!(store.lock().staged.len(), MAX_STAGED);
        assert!(!store.lock().staged.contains_key(&tokens[0]), "the oldest goes first");
    }
}