osp_cli/app/

session.rs

//! Session-scoped host state for one logical app run.
//!
//! This module exists to hold mutable state that should survive across commands
//! within the same session, but should not be promoted to global runtime
//! state.
//!
//! High-level flow:
//!
//! - track prompt timing and last-failure details
//! - maintain REPL scope stack and small in-memory caches
//! - bundle session state that host code needs to carry between dispatches
//!
//! Contract:
//!
//! - session data here is narrower-lived than the runtime state in
//!   [`super::runtime`]
//! - long-lived environment/config/plugin bootstrap state should not drift into
//!   this module
//!
//! Public API shape:
//!
//! - use [`AppSession::builder`] or [`AppSession::with_cache_limit`] plus the
//!   `with_*` chainers for session-scoped REPL state
//! - use [`AppStateBuilder`] when you need a fully assembled runtime/session
//!   snapshot outside the full CLI bootstrap
//! - these types are host machinery, not lightweight semantic DTOs

use std::collections::{HashMap, VecDeque};
use std::sync::{Arc, RwLock};
use std::time::Duration;

use crate::config::{ConfigLayer, DEFAULT_SESSION_CACHE_MAX_RESULTS};
use crate::core::row::Row;
use crate::native::NativeCommandRegistry;
use crate::plugin::PluginManager;
use crate::repl::HistoryShellContext;

use super::command_output::CliCommandResult;
use super::runtime::{AppClients, AppRuntime, LaunchContext, RuntimeContext, UiState};
use super::timing::TimingSummary;

#[derive(Debug, Clone, Copy, Default)]
/// Timing badge rendered in the prompt for the most recent command.
pub struct DebugTimingBadge {
    /// Prompt detail level used when rendering the badge.
    pub level: u8,
    pub(crate) summary: TimingSummary,
}

/// Shared prompt-timing storage that dispatch code can update and prompt
/// rendering can read.
#[derive(Clone, Default, Debug)]
pub struct DebugTimingState {
    inner: Arc<RwLock<Option<DebugTimingBadge>>>,
}

impl DebugTimingState {
    /// Stores the current timing badge.
    pub fn set(&self, badge: DebugTimingBadge) {
        if let Ok(mut guard) = self.inner.write() {
            *guard = Some(badge);
        }
    }

    /// Clears any stored timing badge.
    pub fn clear(&self) {
        if let Ok(mut guard) = self.inner.write() {
            *guard = None;
        }
    }

    /// Returns the current timing badge, if one is available.
    pub fn badge(&self) -> Option<DebugTimingBadge> {
        self.inner.read().map(|value| *value).unwrap_or(None)
    }
}

/// One entered command scope inside the interactive REPL shell stack.
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct ReplScopeFrame {
    command: String,
}

impl ReplScopeFrame {
    /// Creates a frame for the given command name.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::ReplScopeFrame;
    ///
    /// let frame = ReplScopeFrame::new("theme");
    /// assert_eq!(frame.command(), "theme");
    /// ```
    pub fn new(command: impl Into<String>) -> Self {
        Self {
            command: command.into(),
        }
    }

    /// Returns the command name associated with this scope frame.
    pub fn command(&self) -> &str {
        self.command.as_str()
    }
}

/// Nested REPL command-scope stack used for shell-style scoped interaction.
///
/// This is what lets the REPL stay "inside" a command family while still
/// rendering scope labels, help targets, and history prefixes consistently.
#[derive(Debug, Clone, Default, PartialEq, Eq)]
pub struct ReplScopeStack {
    frames: Vec<ReplScopeFrame>,
}

impl ReplScopeStack {
    /// Returns `true` when the REPL is at the top-level scope.
    pub fn is_root(&self) -> bool {
        self.frames.is_empty()
    }

    /// Pushes a new command scope onto the stack.
    pub fn enter(&mut self, command: impl Into<String>) {
        self.frames.push(ReplScopeFrame::new(command));
    }

    /// Pops the current command scope from the stack.
    pub fn leave(&mut self) -> Option<ReplScopeFrame> {
        self.frames.pop()
    }

    /// Returns the command path represented by the current stack.
    pub fn commands(&self) -> Vec<String> {
        self.frames
            .iter()
            .map(|frame| frame.command.clone())
            .collect()
    }

    /// Returns whether the stack already contains the given command.
    pub fn contains_command(&self, command: &str) -> bool {
        self.frames
            .iter()
            .any(|frame| frame.command.eq_ignore_ascii_case(command))
    }

    /// Returns a human-readable label for the current scope path.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::ReplScopeStack;
    ///
    /// let mut scope = ReplScopeStack::default();
    /// assert_eq!(scope.display_label(), None);
    ///
    /// scope.enter("theme");
    /// scope.enter("show");
    /// assert_eq!(scope.display_label(), Some("theme / show".to_string()));
    /// ```
    pub fn display_label(&self) -> Option<String> {
        if self.is_root() {
            None
        } else {
            Some(
                self.frames
                    .iter()
                    .map(|frame| frame.command.as_str())
                    .collect::<Vec<_>>()
                    .join(" / "),
            )
        }
    }

    /// Returns the history prefix used for shell-backed history entries.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::ReplScopeStack;
    ///
    /// let mut scope = ReplScopeStack::default();
    /// scope.enter("theme");
    /// scope.enter("show");
    ///
    /// assert_eq!(scope.history_prefix(), "theme show ");
    /// ```
    pub fn history_prefix(&self) -> String {
        if self.is_root() {
            String::new()
        } else {
            format!(
                "{} ",
                self.frames
                    .iter()
                    .map(|frame| frame.command.as_str())
                    .collect::<Vec<_>>()
                    .join(" ")
            )
        }
    }

    /// Returns the active history scope prefix, if the REPL is inside a shell.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::ReplScopeStack;
    ///
    /// let mut scope = ReplScopeStack::default();
    /// assert_eq!(scope.history_scope_prefix(), None);
    ///
    /// scope.enter("theme");
    /// assert_eq!(scope.history_scope_prefix(), Some("theme ".to_string()));
    /// ```
    pub fn history_scope_prefix(&self) -> Option<String> {
        let prefix = self.history_prefix();
        if prefix.is_empty() {
            None
        } else {
            Some(prefix)
        }
    }

    /// Returns the user-facing label for the current history scope.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::ReplScopeStack;
    ///
    /// let mut scope = ReplScopeStack::default();
    /// assert_eq!(scope.history_scope_label(), "root history");
    ///
    /// scope.enter("theme");
    /// scope.enter("show");
    /// assert_eq!(scope.history_scope_label(), "theme / show shell history");
    /// ```
    pub fn history_scope_label(&self) -> String {
        self.display_label()
            .map(|label| format!("{label} shell history"))
            .unwrap_or_else(|| "root history".to_string())
    }

    /// Prepends the active scope path unless the tokens are already scoped.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::ReplScopeStack;
    ///
    /// let mut scope = ReplScopeStack::default();
    /// scope.enter("theme");
    ///
    /// assert_eq!(
    ///     scope.prefixed_tokens(&["show".to_string(), "dracula".to_string()]),
    ///     vec!["theme".to_string(), "show".to_string(), "dracula".to_string()]
    /// );
    /// ```
    pub fn prefixed_tokens(&self, tokens: &[String]) -> Vec<String> {
        let prefix = self.commands();
        if prefix.is_empty() || tokens.starts_with(&prefix) {
            return tokens.to_vec();
        }
        let mut full = prefix;
        full.extend_from_slice(tokens);
        full
    }

    /// Returns help tokens for the current scope.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::ReplScopeStack;
    ///
    /// let mut scope = ReplScopeStack::default();
    /// scope.enter("theme");
    ///
    /// assert_eq!(scope.help_tokens(), vec!["theme".to_string(), "--help".to_string()]);
    /// ```
    pub fn help_tokens(&self) -> Vec<String> {
        let mut tokens = self.commands();
        if !tokens.is_empty() {
            tokens.push("--help".to_string());
        }
        tokens
    }
}

/// Session-scoped REPL state, caches, and prompt metadata.
#[non_exhaustive]
#[must_use]
pub struct AppSession {
    /// Prompt prefix shown before any scope label.
    pub prompt_prefix: String,
    /// Whether history capture is enabled for this session.
    pub history_enabled: bool,
    /// Shell-scoped history prefix state shared with the history store.
    pub history_shell: HistoryShellContext,
    /// Shared prompt timing badge state.
    pub prompt_timing: DebugTimingState,
    pub(crate) startup_prompt_timing_pending: bool,
    /// Current nested command scope within the REPL.
    pub scope: ReplScopeStack,
    /// Rows returned by the most recent successful REPL command.
    pub last_rows: Vec<Row>,
    /// Summary of the most recent failed REPL command.
    pub last_failure: Option<LastFailure>,
    /// Cached row outputs keyed by command line.
    pub result_cache: HashMap<String, Vec<Row>>,
    /// Eviction order for the row-result cache.
    pub cache_order: VecDeque<String>,
    pub(crate) command_cache: HashMap<String, CliCommandResult>,
    pub(crate) command_cache_order: VecDeque<String>,
    /// Maximum number of cached result sets to retain.
    pub max_cached_results: usize,
    /// Session-scoped config overrides layered above persisted config.
    pub config_overrides: ConfigLayer,
}

#[derive(Debug, Clone, PartialEq, Eq)]
/// Summary of the last failed REPL command.
pub struct LastFailure {
    /// Command line that produced the failure.
    pub command_line: String,
    /// Short failure summary suitable for prompts or status output.
    pub summary: String,
    /// Longer failure detail for follow-up inspection.
    pub detail: String,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub(crate) enum ReplExitTransition {
    ExitRoot,
    LeftShell {
        frame: ReplScopeFrame,
        now_root: bool,
    },
}

#[derive(Debug, Clone)]
pub(crate) struct AppSessionRebuildState {
    prompt_prefix: String,
    history_enabled: bool,
    history_shell: HistoryShellContext,
    prompt_timing: DebugTimingState,
    startup_prompt_timing_pending: bool,
    scope: ReplScopeStack,
    last_rows: Vec<Row>,
    last_failure: Option<LastFailure>,
    result_cache: HashMap<String, Vec<Row>>,
    cache_order: VecDeque<String>,
    max_cached_results: usize,
    config_overrides: ConfigLayer,
}

impl AppSessionRebuildState {
    pub(crate) fn is_scoped(&self) -> bool {
        !self.scope.is_root()
    }

    pub(crate) fn session_layer(&self) -> Option<ConfigLayer> {
        (!self.config_overrides.entries().is_empty()).then(|| self.config_overrides.clone())
    }

    fn restore_into(self, next: &mut AppSession) {
        next.prompt_prefix = self.prompt_prefix;
        next.history_enabled = self.history_enabled;
        next.history_shell = self.history_shell;
        next.prompt_timing = self.prompt_timing;
        next.startup_prompt_timing_pending = self.startup_prompt_timing_pending;
        next.scope = self.scope;
        next.last_rows = self.last_rows;
        next.last_failure = self.last_failure;
        next.result_cache = self.result_cache;
        next.cache_order = self.cache_order;
        // Command execution results depend on live runtime/plugin/config state,
        // so a rebuild keeps row history but must drop command-result caches.
        next.command_cache.clear();
        next.command_cache_order.clear();
        next.max_cached_results = self.max_cached_results;
        next.config_overrides = self.config_overrides;
        next.sync_history_shell_context();
    }
}

impl AppSession {
    /// Starts the builder for session-scoped host state.
    ///
    /// Prefer this when you want a neutral starting point and do not want the
    /// first constructor call to imply that cache sizing is the primary concern.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::AppSession;
    ///
    /// let session = AppSession::builder()
    ///     .with_prompt_prefix("demo")
    ///     .with_history_enabled(false)
    ///     .build();
    ///
    /// assert_eq!(session.prompt_prefix, "demo");
    /// assert!(!session.history_enabled);
    /// ```
    pub fn builder() -> AppSessionBuilder {
        AppSessionBuilder::new()
    }

    /// Creates a session with bounded caches for row and command results.
    ///
    /// A requested cache limit of `0` is clamped to `1` so the session never
    /// stores a zero-capacity cache by accident.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::AppSession;
    ///
    /// let session = AppSession::with_cache_limit(4).with_prompt_prefix("demo");
    ///
    /// assert_eq!(session.max_cached_results, 4);
    /// assert_eq!(session.prompt_prefix, "demo");
    /// ```
    pub fn with_cache_limit(max_cached_results: usize) -> Self {
        let bounded = max_cached_results.max(1);
        Self {
            prompt_prefix: "osp".to_string(),
            history_enabled: true,
            history_shell: HistoryShellContext::default(),
            prompt_timing: DebugTimingState::default(),
            startup_prompt_timing_pending: true,
            scope: ReplScopeStack::default(),
            last_rows: Vec::new(),
            last_failure: None,
            result_cache: HashMap::new(),
            cache_order: VecDeque::new(),
            command_cache: HashMap::new(),
            command_cache_order: VecDeque::new(),
            max_cached_results: bounded,
            config_overrides: ConfigLayer::default(),
        }
    }

    /// Creates the default session snapshot for the current resolved config.
    pub(crate) fn from_resolved_config(config: &crate::config::ResolvedConfig) -> Self {
        let session_cache_max_results = crate::app::config_usize(
            config,
            "session.cache.max_results",
            DEFAULT_SESSION_CACHE_MAX_RESULTS as usize,
        );
        Self::with_cache_limit(session_cache_max_results)
    }

    /// Creates the default session snapshot for the current resolved config
    /// and attaches the supplied session-layer overrides.
    pub(crate) fn from_resolved_config_with_overrides(
        config: &crate::config::ResolvedConfig,
        config_overrides: ConfigLayer,
    ) -> Self {
        Self::with_cache_limit(crate::app::config_usize(
            config,
            "session.cache.max_results",
            DEFAULT_SESSION_CACHE_MAX_RESULTS as usize,
        ))
        .with_config_overrides(config_overrides)
    }

    /// Replaces the prompt prefix shown ahead of any scope label.
    pub fn with_prompt_prefix(mut self, prompt_prefix: impl Into<String>) -> Self {
        self.prompt_prefix = prompt_prefix.into();
        self
    }

    /// Enables or disables history capture for this session.
    pub fn with_history_enabled(mut self, history_enabled: bool) -> Self {
        self.history_enabled = history_enabled;
        self
    }

    /// Replaces the shell-scoped history context shared with the history store.
    pub fn with_history_shell(mut self, history_shell: HistoryShellContext) -> Self {
        self.history_shell = history_shell;
        self
    }

    /// Replaces the session-scoped config overrides layered above persisted config.
    pub fn with_config_overrides(mut self, config_overrides: ConfigLayer) -> Self {
        self.config_overrides = config_overrides;
        self
    }

    /// Enters a nested REPL shell scope and synchronizes history context.
    pub fn enter_repl_scope(&mut self, command: impl Into<String>) {
        self.scope.enter(command);
        self.sync_history_shell_context();
    }

    /// Leaves the current REPL shell scope and synchronizes history context.
    pub fn leave_repl_scope(&mut self) -> Option<ReplScopeFrame> {
        let frame = self.scope.leave()?;
        self.sync_history_shell_context();
        Some(frame)
    }

    /// Applies a user `exit` request against the current REPL scope.
    pub(crate) fn request_repl_exit(&mut self) -> ReplExitTransition {
        if self.scope.is_root() {
            self.sync_history_shell_context();
            ReplExitTransition::ExitRoot
        } else {
            match self.leave_repl_scope() {
                Some(frame) => ReplExitTransition::LeftShell {
                    now_root: self.scope.is_root(),
                    frame,
                },
                None => ReplExitTransition::ExitRoot,
            }
        }
    }

    /// Finalizes a completed REPL line by synchronizing derived session state.
    pub(crate) fn finish_repl_line(&self) {
        self.sync_history_shell_context();
    }

    /// Captures the session-scoped state that must survive a runtime rebuild.
    pub(crate) fn capture_rebuild_state(&self) -> AppSessionRebuildState {
        AppSessionRebuildState {
            prompt_prefix: self.prompt_prefix.clone(),
            history_enabled: self.history_enabled,
            history_shell: self.history_shell.clone(),
            prompt_timing: self.prompt_timing.clone(),
            startup_prompt_timing_pending: self.startup_prompt_timing_pending,
            scope: self.scope.clone(),
            last_rows: self.last_rows.clone(),
            last_failure: self.last_failure.clone(),
            result_cache: self.result_cache.clone(),
            cache_order: self.cache_order.clone(),
            max_cached_results: self.max_cached_results,
            config_overrides: self.config_overrides.clone(),
        }
    }

    /// Restores session-scoped state after a runtime rebuild.
    pub(crate) fn restore_rebuild_state(&mut self, state: AppSessionRebuildState) {
        state.restore_into(self);
    }

    /// Stores the latest successful row output and updates the result cache.
    pub fn record_result(&mut self, command_line: &str, rows: Vec<Row>) {
        let key = command_line.trim().to_string();
        if key.is_empty() {
            return;
        }

        self.last_rows = rows.clone();
        if !self.result_cache.contains_key(&key)
            && self.result_cache.len() >= self.max_cached_results
            && let Some(evict_key) = self.cache_order.pop_front()
        {
            self.result_cache.remove(&evict_key);
        }

        self.cache_order.retain(|item| item != &key);
        self.cache_order.push_back(key.clone());
        self.result_cache.insert(key, rows);
    }

    /// Records details about the latest failed command.
    pub fn record_failure(
        &mut self,
        command_line: &str,
        summary: impl Into<String>,
        detail: impl Into<String>,
    ) {
        let command_line = command_line.trim().to_string();
        if command_line.is_empty() {
            return;
        }
        self.last_failure = Some(LastFailure {
            command_line,
            summary: summary.into(),
            detail: detail.into(),
        });
    }

    /// Returns cached rows for a previously executed command line.
    pub fn cached_rows(&self, command_line: &str) -> Option<&[Row]> {
        self.result_cache
            .get(command_line.trim())
            .map(|rows| rows.as_slice())
    }

    pub(crate) fn record_cached_command(&mut self, cache_key: &str, result: &CliCommandResult) {
        let cache_key = cache_key.trim().to_string();
        if cache_key.is_empty() {
            return;
        }

        if !self.command_cache.contains_key(&cache_key)
            && self.command_cache.len() >= self.max_cached_results
            && let Some(evict_key) = self.command_cache_order.pop_front()
        {
            self.command_cache.remove(&evict_key);
        }

        self.command_cache_order.retain(|item| item != &cache_key);
        self.command_cache_order.push_back(cache_key.clone());
        self.command_cache.insert(cache_key, result.clone());
    }

    pub(crate) fn cached_command(&self, cache_key: &str) -> Option<CliCommandResult> {
        self.command_cache.get(cache_key.trim()).cloned()
    }

    /// Updates the prompt timing badge for the most recent command.
    pub fn record_prompt_timing(
        &self,
        level: u8,
        total: Duration,
        parse: Option<Duration>,
        execute: Option<Duration>,
        render: Option<Duration>,
    ) {
        if level == 0 {
            self.prompt_timing.clear();
            return;
        }

        self.prompt_timing.set(DebugTimingBadge {
            level,
            summary: TimingSummary {
                total,
                parse,
                execute,
                render,
            },
        });
    }

    /// Seeds the initial prompt timing badge emitted during startup.
    pub fn seed_startup_prompt_timing(&mut self, level: u8, total: Duration) {
        if !self.startup_prompt_timing_pending {
            return;
        }
        self.startup_prompt_timing_pending = false;
        if level == 0 {
            return;
        }

        self.prompt_timing.set(DebugTimingBadge {
            level,
            summary: TimingSummary {
                total,
                parse: None,
                execute: None,
                render: None,
            },
        });
    }

    /// Synchronizes history context with the current REPL scope.
    pub fn sync_history_shell_context(&self) {
        self.history_shell.set_prefix(self.scope.history_prefix());
    }
}

impl Default for AppSession {
    fn default() -> Self {
        Self::with_cache_limit(DEFAULT_SESSION_CACHE_MAX_RESULTS as usize)
    }
}

/// Builder for [`AppSession`].
///
/// Prefer this when callers want a neutral session-construction entrypoint and
/// plan to configure prompt/history behavior before building the final value.
#[must_use]
pub struct AppSessionBuilder {
    prompt_prefix: String,
    history_enabled: bool,
    history_shell: HistoryShellContext,
    max_cached_results: usize,
    config_overrides: ConfigLayer,
}

impl Default for AppSessionBuilder {
    fn default() -> Self {
        Self::new()
    }
}

impl AppSessionBuilder {
    /// Starts a session builder with the crate's default prompt and cache size.
    pub fn new() -> Self {
        Self {
            prompt_prefix: "osp".to_string(),
            history_enabled: true,
            history_shell: HistoryShellContext::default(),
            max_cached_results: DEFAULT_SESSION_CACHE_MAX_RESULTS as usize,
            config_overrides: ConfigLayer::default(),
        }
    }

    /// Replaces the prompt prefix shown ahead of any scope label.
    pub fn with_prompt_prefix(mut self, prompt_prefix: impl Into<String>) -> Self {
        self.prompt_prefix = prompt_prefix.into();
        self
    }

    /// Enables or disables history capture for the built session.
    pub fn with_history_enabled(mut self, history_enabled: bool) -> Self {
        self.history_enabled = history_enabled;
        self
    }

    /// Replaces the shell-scoped history context shared with the history store.
    pub fn with_history_shell(mut self, history_shell: HistoryShellContext) -> Self {
        self.history_shell = history_shell;
        self
    }

    /// Replaces the maximum number of cached row/command results.
    pub fn with_cache_limit(mut self, max_cached_results: usize) -> Self {
        self.max_cached_results = max_cached_results;
        self
    }

    /// Replaces the session-scoped config overrides layered above persisted config.
    pub fn with_config_overrides(mut self, config_overrides: ConfigLayer) -> Self {
        self.config_overrides = config_overrides;
        self
    }

    /// Builds the configured [`AppSession`].
    pub fn build(self) -> AppSession {
        AppSession::with_cache_limit(self.max_cached_results)
            .with_prompt_prefix(self.prompt_prefix)
            .with_history_enabled(self.history_enabled)
            .with_history_shell(self.history_shell)
            .with_config_overrides(self.config_overrides)
    }
}

pub(crate) struct AppStateInit {
    pub context: RuntimeContext,
    pub config: crate::config::ResolvedConfig,
    pub render_settings: crate::ui::RenderSettings,
    pub message_verbosity: crate::ui::messages::MessageLevel,
    pub debug_verbosity: u8,
    pub plugins: crate::plugin::PluginManager,
    pub native_commands: NativeCommandRegistry,
    pub themes: crate::ui::theme_catalog::ThemeCatalog,
    pub launch: LaunchContext,
}

pub(crate) struct AppStateParts {
    pub runtime: AppRuntime,
    pub session: AppSession,
    pub clients: AppClients,
}

impl AppStateParts {
    fn from_init(init: AppStateInit, session_override: Option<AppSession>) -> Self {
        let clients = AppClients::new(init.plugins, init.native_commands);
        let config = crate::app::ConfigState::new(init.config);
        let ui = crate::app::UiState::new(
            init.render_settings,
            init.message_verbosity,
            init.debug_verbosity,
        );
        let auth = crate::app::AuthState::from_resolved_with_external_policies(
            config.resolved(),
            clients.plugins(),
            clients.native_commands(),
        );
        let runtime = AppRuntime::new(init.context, config, ui, auth, init.themes, init.launch);
        let session = session_override
            .unwrap_or_else(|| AppSession::from_resolved_config(runtime.config.resolved()));

        Self {
            runtime,
            session,
            clients,
        }
    }
}

/// Aggregate application state shared between runtime and session logic.
#[non_exhaustive]
#[must_use]
pub struct AppState {
    /// Runtime-scoped services and resolved config state.
    pub runtime: AppRuntime,
    /// Session-scoped REPL caches and prompt metadata.
    pub session: AppSession,
    /// Shared client registries used during command execution.
    pub clients: AppClients,
}

impl AppState {
    /// Builds a full application-state snapshot by deriving UI state from the
    /// resolved config and runtime context.
    ///
    /// # Examples
    ///
    /// ```
    /// use osp_cli::app::{AppState, RuntimeContext, TerminalKind};
    /// use osp_cli::config::{ConfigLayer, ConfigResolver, ResolveOptions};
    ///
    /// let mut defaults = ConfigLayer::default();
    /// defaults.set("profile.default", "default");
    /// defaults.set("ui.message.verbosity", "warning");
    ///
    /// let mut resolver = ConfigResolver::default();
    /// resolver.set_defaults(defaults);
    /// let config = resolver.resolve(ResolveOptions::new().with_terminal("repl")).unwrap();
    ///
    /// let state = AppState::from_resolved_config(
    ///     RuntimeContext::new(None, TerminalKind::Repl, None),
    ///     config,
    /// )
    /// .unwrap();
    ///
    /// assert_eq!(state.runtime.config.resolved().active_profile(), "default");
    /// assert_eq!(state.runtime.ui.message_verbosity.as_env_str(), "warning");
    /// assert!(state.clients.plugins().explicit_dirs().is_empty());
    /// ```
    pub fn from_resolved_config(
        context: RuntimeContext,
        config: crate::config::ResolvedConfig,
    ) -> miette::Result<Self> {
        AppStateBuilder::from_resolved_config(context, config).map(AppStateBuilder::build)
    }

    #[cfg(test)]
    pub(crate) fn new(init: AppStateInit) -> Self {
        Self::from_parts(AppStateParts::from_init(init, None))
    }

    pub(crate) fn from_parts(parts: AppStateParts) -> Self {
        Self {
            runtime: parts.runtime,
            session: parts.session,
            clients: parts.clients,
        }
    }

    pub(crate) fn replace_parts(&mut self, parts: AppStateParts) {
        self.runtime = parts.runtime;
        self.session = parts.session;
        self.clients = parts.clients;
    }

    /// Returns the prompt prefix configured for the current session.
    pub fn prompt_prefix(&self) -> String {
        self.session.prompt_prefix.clone()
    }

    /// Synchronizes the history shell context with the current session scope.
    pub fn sync_history_shell_context(&self) {
        self.session.sync_history_shell_context();
    }

    /// Records rows produced by a REPL command.
    pub fn record_repl_rows(&mut self, command_line: &str, rows: Vec<Row>) {
        self.session.record_result(command_line, rows);
    }

    /// Records a failed REPL command and its associated messages.
    pub fn record_repl_failure(
        &mut self,
        command_line: &str,
        summary: impl Into<String>,
        detail: impl Into<String>,
    ) {
        self.session.record_failure(command_line, summary, detail);
    }

    /// Returns the rows from the most recent successful REPL command.
    pub fn last_repl_rows(&self) -> Vec<Row> {
        self.session.last_rows.clone()
    }

    /// Returns details about the most recent failed REPL command.
    pub fn last_repl_failure(&self) -> Option<LastFailure> {
        self.session.last_failure.clone()
    }

    /// Returns cached rows for a previously executed REPL command.
    pub fn cached_repl_rows(&self, command_line: &str) -> Option<Vec<Row>> {
        self.session
            .cached_rows(command_line)
            .map(ToOwned::to_owned)
    }

    /// Returns the number of cached REPL result sets.
    pub fn repl_cache_size(&self) -> usize {
        self.session.result_cache.len()
    }
}

/// Builder for [`AppState`].
///
/// This is the canonical manual-construction factory for runtime/session/client
/// state when callers need a snapshot without going through full CLI bootstrap.
///
/// Use [`AppStateBuilder::from_resolved_config`] for the normal config-driven
/// path, then override specific pieces such as the session or plugin manager as
/// needed. Use [`AppStateBuilder::new`] only when the caller already has a
/// fully chosen [`UiState`] and wants the builder to assemble the remaining
/// runtime/session/client pieces around it.
///
/// # Examples
///
/// ```
/// use osp_cli::app::{AppSession, AppStateBuilder, RuntimeContext, TerminalKind};
/// use osp_cli::config::{ConfigLayer, ConfigResolver, ResolveOptions};
///
/// let mut defaults = ConfigLayer::default();
/// defaults.set("profile.default", "default");
///
/// let mut resolver = ConfigResolver::default();
/// resolver.set_defaults(defaults);
/// let config = resolver.resolve(ResolveOptions::new().with_terminal("repl")).unwrap();
///
/// let state = AppStateBuilder::from_resolved_config(
///     RuntimeContext::new(None, TerminalKind::Repl, None),
///     config,
/// )?
/// .with_session(AppSession::with_cache_limit(32).with_prompt_prefix("demo"))
/// .build();
///
/// assert_eq!(state.prompt_prefix(), "demo");
/// # Ok::<(), miette::Report>(())
/// ```
#[must_use]
pub struct AppStateBuilder {
    context: RuntimeContext,
    config: crate::config::ResolvedConfig,
    ui: UiState,
    launch: LaunchContext,
    plugins: Option<PluginManager>,
    native_commands: NativeCommandRegistry,
    session: Option<AppSession>,
    themes: Option<crate::ui::theme_catalog::ThemeCatalog>,
}

impl AppStateBuilder {
    /// Starts building an application-state snapshot from the resolved config
    /// and UI state the caller wants to expose.
    ///
    /// This is the manual-construction path. Prefer
    /// [`AppStateBuilder::from_resolved_config`] when the builder should derive
    /// UI defaults from config and runtime context first.
    pub fn new(
        context: RuntimeContext,
        config: crate::config::ResolvedConfig,
        ui: UiState,
    ) -> Self {
        Self {
            context,
            config,
            ui,
            launch: LaunchContext::default(),
            plugins: None,
            native_commands: NativeCommandRegistry::default(),
            session: None,
            themes: None,
        }
    }

    pub(crate) fn from_host_inputs(
        context: RuntimeContext,
        config: crate::config::ResolvedConfig,
        host_inputs: crate::app::assembly::ResolvedHostInputs,
    ) -> Self {
        Self {
            context,
            config,
            ui: host_inputs.ui,
            launch: LaunchContext::default(),
            plugins: Some(host_inputs.plugins),
            native_commands: NativeCommandRegistry::default(),
            session: Some(host_inputs.default_session),
            themes: Some(host_inputs.themes),
        }
    }

    /// Starts a builder by deriving UI state from the resolved config and
    /// runtime context.
    ///
    /// This is the canonical embedder entrypoint when you want one coherent
    /// host snapshot and only plan to override selected pieces before build.
    pub fn from_resolved_config(
        context: RuntimeContext,
        config: crate::config::ResolvedConfig,
    ) -> miette::Result<Self> {
        // This path is the canonical embedder factory: derive host inputs once
        // and hand callers a coherent runtime/session snapshot. Plugins are
        // intentionally derived later at build time from the final launch
        // context, because callers may still override launch roots before the
        // state is assembled.
        let host_inputs = crate::app::assembly::ResolvedHostInputs::derive(
            &context,
            &config,
            &LaunchContext::default(),
            crate::app::assembly::RenderSettingsSeed::DefaultAuto,
            None,
            None,
            None,
        )?;
        crate::ui::theme_catalog::log_theme_issues(&host_inputs.themes.issues);
        Ok(Self {
            context,
            config,
            ui: host_inputs.ui,
            launch: LaunchContext::default(),
            plugins: None,
            native_commands: NativeCommandRegistry::default(),
            session: Some(host_inputs.default_session),
            themes: Some(host_inputs.themes),
        })
    }

    /// Replaces the launch-time provenance used for cache and plugin setup.
    ///
    /// If omitted, the builder keeps [`LaunchContext::default`].
    pub fn with_launch(mut self, launch: LaunchContext) -> Self {
        self.launch = launch;
        self
    }

    /// Replaces the plugin manager used when assembling shared clients.
    ///
    /// If omitted, the builder derives the plugin manager from the resolved
    /// config plus the current launch context during [`AppStateBuilder::build`].
    pub fn with_plugins(mut self, plugins: PluginManager) -> Self {
        self.plugins = Some(plugins);
        self
    }

    /// Replaces the native command registry used when assembling shared
    /// clients.
    ///
    /// If omitted, the builder keeps [`NativeCommandRegistry::default`].
    pub fn with_native_commands(mut self, native_commands: NativeCommandRegistry) -> Self {
        self.native_commands = native_commands;
        self
    }

    /// Replaces the session snapshot carried by the built app state.
    ///
    /// If omitted, the builder uses the derived/default session for the
    /// current config.
    pub fn with_session(mut self, session: AppSession) -> Self {
        self.session = Some(session);
        self
    }

    /// Builds the configured [`AppState`].
    ///
    /// This assembles one coherent runtime/session/client snapshot, deriving any
    /// omitted pieces such as themes, plugin manager, and default session before
    /// returning the final value.
    pub fn build(self) -> AppState {
        let Self {
            context,
            config,
            ui,
            launch,
            plugins,
            native_commands,
            session,
            themes,
        } = self;
        let should_log_theme_issues = themes.is_none();
        let derived_defaults = if themes.is_none() || plugins.is_none() || session.is_none() {
            Some(crate::app::assembly::derive_host_defaults(
                &config, &launch, None, None,
            ))
        } else {
            None
        };
        let (derived_themes, derived_plugins, derived_session) = match derived_defaults {
            Some(defaults) => (
                Some(defaults.themes),
                Some(defaults.plugins),
                Some(defaults.default_session),
            ),
            None => (None, None, None),
        };
        let themes = themes.or(derived_themes).unwrap_or_else(|| {
            crate::app::assembly::derive_host_defaults(&config, &launch, None, None).themes
        });
        let plugins = plugins.or(derived_plugins).unwrap_or_else(|| {
            crate::app::assembly::derive_host_defaults(&config, &launch, None, None).plugins
        });
        let session = session.or(derived_session).or_else(|| {
            Some(
                crate::app::assembly::derive_host_defaults(&config, &launch, None, None)
                    .default_session,
            )
        });
        if should_log_theme_issues {
            crate::ui::theme_catalog::log_theme_issues(&themes.issues);
        }

        let crate::app::UiState {
            render_settings,
            message_verbosity,
            debug_verbosity,
            ..
        } = ui;

        AppState::from_parts(AppStateParts::from_init(
            AppStateInit {
                context,
                config,
                render_settings,
                message_verbosity,
                debug_verbosity,
                plugins,
                native_commands,
                themes,
                launch,
            },
            session,
        ))
    }
}

#[cfg(test)]
mod tests {
    use std::time::Duration;

    use serde_json::Value;

    use super::{AppSession, ReplExitTransition};
    use crate::config::ConfigLayer;

    #[test]
    fn request_repl_exit_tracks_root_and_nested_scope_transitions_unit() {
        let mut root = AppSession::with_cache_limit(4);
        assert!(matches!(
            root.request_repl_exit(),
            ReplExitTransition::ExitRoot
        ));

        let mut nested = AppSession::with_cache_limit(4);
        nested.enter_repl_scope("ldap");
        assert!(matches!(
            nested.request_repl_exit(),
            ReplExitTransition::LeftShell {
                now_root: true,
                frame,
            } if frame.command() == "ldap"
        ));
        assert!(nested.scope.is_root());

        let mut deep = AppSession::with_cache_limit(4);
        deep.enter_repl_scope("ldap");
        deep.enter_repl_scope("user");
        assert!(matches!(
            deep.request_repl_exit(),
            ReplExitTransition::LeftShell {
                now_root: false,
                frame,
            } if frame.command() == "user"
        ));
        assert_eq!(deep.scope.commands(), vec!["ldap".to_string()]);
    }

    #[test]
    fn rebuild_state_round_trip_preserves_rows_and_scope_unit() {
        let mut session = AppSession::with_cache_limit(4)
            .with_prompt_prefix("osp-dev")
            .with_history_enabled(false);
        let mut overrides = ConfigLayer::default();
        overrides.set("ui.format", "json");
        session = session.with_config_overrides(overrides);
        session.max_cached_results = 7;
        session.enter_repl_scope("ldap");
        session.enter_repl_scope("user");
        session.record_prompt_timing(2, Duration::from_secs(3), None, None, None);
        session.startup_prompt_timing_pending = false;

        let mut row = crate::core::row::Row::new();
        row.insert("name".to_string(), Value::from("alice"));
        session.record_result("list users", vec![row.clone()]);
        session.record_failure("list users", "Command failed", "detail");
        session.record_cached_command("config show", &super::CliCommandResult::text("cached"));

        let snapshot = session.capture_rebuild_state();
        let mut restored = AppSession::with_cache_limit(1);
        restored.restore_rebuild_state(snapshot);

        assert_eq!(restored.prompt_prefix, "osp-dev");
        assert!(!restored.history_enabled);
        assert_eq!(restored.max_cached_results, 7);
        assert_eq!(
            restored.scope.commands(),
            vec!["ldap".to_string(), "user".to_string()]
        );
        assert_eq!(
            restored.history_shell.prefix(),
            Some("ldap user ".to_string())
        );
        assert_eq!(restored.cached_rows("list users"), Some(&[row][..]));
        assert!(restored.command_cache.is_empty());
        assert!(restored.command_cache_order.is_empty());
        assert_eq!(
            restored
                .last_failure
                .as_ref()
                .map(|failure| failure.summary.as_str()),
            Some("Command failed")
        );
        assert_eq!(
            restored.prompt_timing.badge().map(|badge| badge.level),
            Some(2)
        );
        assert!(!restored.startup_prompt_timing_pending);
        assert_eq!(restored.config_overrides.entries().len(), 1);
        assert_eq!(restored.config_overrides.entries()[0].key, "ui.format");
        assert_eq!(
            restored.config_overrides.entries()[0].value.to_string(),
            "json"
        );
    }
}