//! Top-level mutable application state (`AppStateRest`) and the transcript
//! display type it owns.
//!
//! `AppStateRest` is the single source-of-truth struct mutated in-place from
//! `actions/mod.rs` and `controller/input.rs`; every other module reads it.

use std::collections::VecDeque;
use std::path::PathBuf;
use std::sync::{Arc, Mutex};
use tokio::sync::RwLock;

use super::input::InputState;
use super::misc::{DirCache, MentionIndex, MiscState};
use super::scroll::ScrollState;
use super::runtime::{SessionRuntime, TurnEvent};
use super::types::{Origin, Toast, TranscriptCache};
use crate::app::lsp::LspManager;
use crate::app::mcp::manager::McpManager;
use crate::app::workflow::engine::WorkflowEngine;
use zesdex_cms::domain::app_config::AppConfig;
use zesdex_cms::domain::edit_log::EditLog;
use zesdex_cms::domain::repository::AppConfigRepository;
use zesdex_cms::domain::repository::EditLogRepository;
use zesdex_cms::domain::repository::SettingsRepository;
use zesdex_cms::domain::settings::Settings;
use zesdex_cms::infrastructure::persistence::app_config_repo::JsonAppConfigRepository;
use zesdex_cms::infrastructure::persistence::edit_log_repo::JsonlEditLogRepository;
use zesdex_cms::infrastructure::persistence::settings_repo::JsonSettingsRepository;

/// A single transcript entry rendered in the TUI chat pane.
#[derive(Debug, Clone, PartialEq)]
pub struct ChatMessageDisplay {
    pub role: crate::dto::chat::message::Role,
    pub content: String,
    pub timestamp: i64,
}

impl ChatMessageDisplay {
    /// Build a display entry, stamping it with the current time.
    pub fn new(role: crate::dto::chat::message::Role, content: String) -> Self {
        ChatMessageDisplay {
            role,
            content,
            timestamp: chrono::Utc::now().timestamp_millis(),
        }
    }
}

/// The single source-of-truth state struct for the entire application.
///
/// Mutated in-place from two locations: `actions/mod.rs` (`apply_action`)
/// and `controller/input.rs` (key event handlers). Read-only from every
/// other module.
#[derive(Clone)]
pub struct AppStateRest {
    pub settings: Settings,
    pub app_config: AppConfig,
    pub workspace_roots: Vec<PathBuf>,
    pub session_id: String,
    pub session_dir: PathBuf,
    pub memory_dir: PathBuf,
    pub worktrees_dir: PathBuf,
    pub dir_cache: Arc<RwLock<DirCache>>,
    pub mention_index: MentionIndex,
    pub edit_log: EditLog,
    pub session_runtime: Option<SessionRuntime>,
    pub sessions: Vec<zesdex_iam::domain::session::Session>,
    pub transcript_cache: TranscriptCache,
    pub scroll: ScrollState,
    pub input: InputState,
    pub misc: MiscState,
    pub turn_events: Arc<Mutex<VecDeque<TurnEvent>>>,
    pub turn_in_flight: Arc<Mutex<bool>>,
    pub abort_flag: Arc<std::sync::atomic::AtomicBool>,
    pub workflow_engine: WorkflowEngine,
    pub mcp_manager: McpManager,
    pub lsp_manager: Arc<Mutex<LspManager>>,
    /// Shared queue: provisioner thread pushes status updates,
    /// drained into toasts on each Tick.
    pub lsp_provision_msgs: Arc<Mutex<VecDeque<String>>>,
    pub dirty: bool,
    pub quit: bool,
}

impl AppStateRest {
    /// Construct the initial application state for a session.
    ///
    /// Flow: load settings/config -> derive download/worktree dirs from
    /// `memory_dir`'s parent -> derive `session_id` from the session dir's
    /// file name -> build the sub-state structs.
    ///
    /// Why: falls back to `memory_dir` itself (with a warning) when it has
    /// no parent, and to an empty session id when the dir name can't be
    /// read, so construction never fails.
    pub fn new(
        workspace_roots: Vec<PathBuf>,
        session_dir: &std::path::Path,
        memory_dir: PathBuf,
    ) -> Self {
        let store_base_dir = zesdex_entities::domain::common::store::Store::new().base_dir;
        let settings = JsonSettingsRepository::new()
            .load(&store_base_dir)
            .unwrap_or_default();
        let app_config = JsonAppConfigRepository::new()
            .load(&store_base_dir)
            .unwrap_or_default();
        let worktrees_dir = memory_dir
            .parent()
            .unwrap_or_else(|| {
                tracing::warn!(
                    "[state] memory_dir '{}' has no parent, using it for worktrees",
                    memory_dir.display()
                );
                &memory_dir
            })
            .join("worktrees");
        let dir_cache = DirCache::new();
        let session_id = session_dir.file_name().map_or_else(
            || {
                tracing::warn!(
                    "[state] session_dir has no file_name component, using empty session_id"
                );
                String::new()
            },
            |n| n.to_string_lossy().to_string(),
        );
        let mut state = AppStateRest {
            settings,
            app_config,
            workspace_roots,
            session_id,
            session_dir: session_dir.to_path_buf(),
            memory_dir,
            worktrees_dir,
            turn_events: Arc::new(Mutex::new(VecDeque::new())),
            turn_in_flight: Arc::new(Mutex::new(false)),
            abort_flag: Arc::new(std::sync::atomic::AtomicBool::new(false)),
            dir_cache: Arc::new(RwLock::new(dir_cache)),
            mention_index: MentionIndex::new(),
            edit_log: JsonlEditLogRepository::new()
                .open(session_dir)
                .unwrap_or_else(|e| {
                    tracing::warn!(
                        "[state] failed to open edit log at '{}': {e}",
                        session_dir.display()
                    );
                    EditLog::new()
                }),
            session_runtime: Some(SessionRuntime::new(session_dir.to_path_buf())),
            workflow_engine: WorkflowEngine::new(),
            mcp_manager: McpManager::new(),
            lsp_provision_msgs: Arc::new(Mutex::new(VecDeque::new())),
            lsp_manager: Arc::new(Mutex::new(LspManager::new())),
            sessions: Vec::new(),
            transcript_cache: TranscriptCache::new(200),
            scroll: ScrollState::new(),
            input: InputState::new(),
            misc: MiscState::new(),
            dirty: true,
            quit: false,
        };

        // Load project-specific history
        let base_dir = state.memory_dir.parent().unwrap_or(&state.memory_dir);
        if let Some(root) = state.workspace_roots.first() {
            if let Ok(abs_root) = std::fs::canonicalize(root) {
                use sha2::Digest;
                let mut hasher = sha2::Sha256::new();
                hasher.update(abs_root.to_string_lossy().as_bytes());
                let hash_hex = hex::encode(hasher.finalize());
                let folder_name = abs_root
                    .file_name()
                    .map_or_else(|| "root".to_string(), |n| n.to_string_lossy().to_string());
                let history_filename = format!("{}-{}.txt", folder_name, &hash_hex[..8]);
                let history_dir = base_dir.join("history");
                let _ = std::fs::create_dir_all(&history_dir);
                let history_file = history_dir.join(history_filename);

                if let Ok(content) = std::fs::read_to_string(&history_file) {
                    let history: Vec<String> = content
                        .lines()
                        .map(std::string::ToString::to_string)
                        .filter(|s| !s.is_empty())
                        .collect();
                    state.input.history = history;
                }
                state.input.history_file = Some(history_file);
            }
        }

        // Fire-and-forget background LSP provisioning.
        //
        // Flow: spawn OS thread -> provision_all() probes/installs every
        // supported language server -> auto_connect() attaches whichever
        // ones ended up available to the shared `lsp_manager` -> log a line
        // per connected server and per failure.
        //
        // Why a raw thread and not a tokio task: this runs before the async
        // runtime's executor may be fully set up for this state, and the
        // provisioning work (shelling out to package managers, network
        // downloads) is blocking I/O; a dedicated thread keeps it off any
        // async executor entirely. It is deliberately not joined -- startup
        // must not block on language server installation, and failures are
        // logged rather than surfaced, since editing still works without LSP.
        if state.settings.flags.lsp_auto_provision {
            let lsp_mgr = state.lsp_manager.clone();
            let msg_queue = state.lsp_provision_msgs.clone();
            std::thread::spawn(move || {
                use crate::app::lsp::provisioner::{self, ProvisionResult};

                fn push_msg(q: &Arc<Mutex<VecDeque<String>>>, msg: &str) {
                    if let Ok(mut q) = q.lock() {
                        q.push_back(msg.to_string());
                    }
                }

                // Wrap the msg_queue in a static-lifetime closure for use as ProgressFn.
                let progress: provisioner::ProgressFn =
                    Some(&|msg: &str| push_msg(&msg_queue, msg));

                let report = |msg: &str| {
                    if let Some(f) = &progress {
                        f(msg);
                    }
                };

                report("LSP: provisioning servers...");
                let results = provisioner::provision_all_with_progress(progress);
                report("LSP: connecting servers...");
                let connected = provisioner::auto_connect(&lsp_mgr, &results);
                for name in &connected {
                    tracing::info!("LSP: {} connected", name);
                    let m = format!("LSP: {name} connected ✓");
                    push_msg(&msg_queue, &m);
                }
                for r in &results {
                    if let ProvisionResult::Failed {
                        language,
                        server_name,
                        reason,
                        ..
                    } = r
                    {
                        tracing::warn!("LSP {} ({}): {}", server_name, language, reason);
                        let m = format!("LSP: {server_name} ({language}) ✗ - {reason}");
                        push_msg(&msg_queue, &m);
                    }
                }
                if connected.is_empty() {
                    let m = "LSP: no servers available — install manually or check prerequisites"
                        .to_string();
                    push_msg(&msg_queue, &m);
                } else {
                    let m = format!("LSP: {} server(s) connected", connected.len());
                    push_msg(&msg_queue, &m);
                }
            });
        }

        state
    }

    /// Spawn the background thread that walks every workspace root and
    /// populates `mention_index` for `@file` mention autocomplete.
    ///
    /// Why a separate method, not called from `new()`: the attach-only
    /// TUI client also constructs an `AppStateRest` (for local rendering
    /// state) but never runs tools or `handle_key` locally — it forwards
    /// keystrokes to the daemon over IPC, which has its own `AppStateRest`
    /// with its own index. Spawning this walk in the attach client would
    /// waste a full workspace scan for an index nothing there consumes.
    /// Callers that DO need the index (single-process mode, the daemon)
    /// call this explicitly after construction.
    ///
    /// Flow: spawn OS thread -> `ignore::Walk` each workspace root,
    /// collecting file paths (workspace-index-prefixed for roots beyond
    /// the first, matching `resolve_path`'s `[N]path` convention) -> stop
    /// once 50,000 entries are collected -> store the result in
    /// `mention_index`.
    ///
    /// Why a raw thread and not a background tokio task: there is no
    /// persistent async runtime driving the render loop, and this is
    /// blocking filesystem I/O -- a dedicated thread keeps startup
    /// non-blocking. Not joined, same rationale as the LSP provisioning
    /// thread above: a slow/huge repo must not delay the TUI appearing.
    pub fn spawn_mention_index_build(&self) {
        let mention_index = self.mention_index.clone();
        let roots = self.workspace_roots.clone();
        std::thread::spawn(move || {
            const MAX_MENTION_ENTRIES: usize = 50_000;
            let mut paths = Vec::new();
            'roots: for (i, root) in roots.iter().enumerate() {
                for entry in ignore::Walk::new(root).flatten() {
                    if !entry.path().is_file() {
                        continue;
                    }
                    let rel = entry.path().strip_prefix(root).unwrap_or(entry.path());
                    let rel_str = rel.display().to_string();
                    let formatted = if i == 0 {
                        rel_str
                    } else {
                        format!("[{i}]{rel_str}")
                    };
                    paths.push(formatted);
                    if paths.len() >= MAX_MENTION_ENTRIES {
                        break 'roots;
                    }
                }
            }
            mention_index.set(paths);
        });
    }

    /// Whether an agent turn is currently running.
    ///
    /// Return: `false` (and logs a warning) if the mutex is poisoned, rather
    /// than propagating a panic.
    pub fn turn_in_flight(&self) -> bool {
        self.turn_in_flight.lock().map_or_else(
            |_| {
                tracing::warn!("[state] turn_in_flight mutex poisoned");
                false
            },
            |g| *g,
        )
    }

    /// Shut down every running LSP server process.
    ///
    /// Why: called on app exit so language servers don't linger as orphaned
    /// processes; silently no-ops if the mutex is poisoned since there is
    /// nothing more useful to do at shutdown time.
    pub fn shutdown_lsp(&mut self) {
        if let Ok(mut mgr) = self.lsp_manager.lock() {
            mgr.shutdown_all();
        }
    }

    /// Append a message to the transcript, evicting the oldest entry once
    /// `max_lines` is exceeded, and mark both the cache and the app dirty.
    pub fn push_transcript(&mut self, msg: ChatMessageDisplay) {
        self.transcript_cache.messages.push(msg);
        if self.transcript_cache.messages.len() > self.transcript_cache.max_lines {
            self.transcript_cache.messages.remove(0);
        }
        self.transcript_cache.dirty = true;
        self.dirty = true;
    }

    /// Mark the app state as dirty, triggering a TUI re-render on the next frame.
    pub fn mark_dirty(&mut self) {
        self.dirty = true;
    }

    /// Queue a toast notification for display and mark the app dirty.
    pub fn push_toast(&mut self, toast: Toast) {
        self.misc.push_toast(toast);
        self.mark_dirty();
    }

    /// Push an info toast with the given message.
    pub fn toast_info(&mut self, msg: impl Into<String>) {
        self.push_toast(Toast::new(super::types::ToastKind::Info, msg.into()));
    }

    /// Push a success toast with the given message.
    pub fn toast_success(&mut self, msg: impl Into<String>) {
        self.push_toast(Toast::new(super::types::ToastKind::Success, msg.into()));
    }

    /// Push a warning toast with the given message.
    pub fn toast_warning(&mut self, msg: impl Into<String>) {
        self.push_toast(Toast::new(super::types::ToastKind::Warning, msg.into()));
    }

    /// Push an error toast with the given message.
    pub fn toast_error(&mut self, msg: impl Into<String>) {
        self.push_toast(Toast::new(super::types::ToastKind::Error, msg.into()));
    }

    /// Resolve the base directory that stores this session (grandparent of
    /// `session_dir`, i.e. the sessions root, not the individual session
    /// folder).
    ///
    /// Why: falls back progressively -- grandparent, then parent, then
    /// `session_dir` itself -- logging a warning at each step down, so this
    /// never fails even on a shallow path.
    pub fn store_base_dir(&self) -> std::path::PathBuf {
        self.session_dir
            .parent()
            .and_then(|p| p.parent())
            .map_or_else(
                || {
                    tracing::warn!(
                        "[state] session_dir '{}' has no grandparent, using parent",
                        self.session_dir.display()
                    );
                    self.session_dir.parent().map_or_else(
                        || {
                            tracing::warn!(
                                "[state] session_dir '{}' has no parent at all, using itself",
                                self.session_dir.display()
                            );
                            self.session_dir.clone()
                        },
                        std::path::Path::to_path_buf,
                    )
                },
                std::path::Path::to_path_buf,
            )
    }

    /// Persist the current settings to the store and swallow any error.
    ///
    /// Inline usage of `JsonSettingsRepository::new().save(...)` was
    /// duplicated twice in `controller/input.rs` — this helper centralises
    /// the call site.
    pub fn save_settings(&self) {
        use zesdex_cms::domain::repository::SettingsRepository;
        let _ = zesdex_cms::infrastructure::persistence::settings_repo::JsonSettingsRepository::new()
            .save(&self.store_base_dir(), &self.settings);
    }

    /// Build a `ToolCtx` for tool calls originating from the main agent.
    pub fn tool_ctx(&self) -> crate::tool::ToolCtx {
        self.tool_ctx_for(Origin::Main)
    }

    /// Build a `ToolCtx` scoped to the given call origin (main, subagent,
    /// reviewer), copying workspace/session/memory paths from state.
    pub fn tool_ctx_for(&self, origin: Origin) -> crate::tool::ToolCtx {
        crate::tool::ToolCtx {
            workspaces: self.workspace_roots.clone(),
            session_dir: self.session_dir.clone(),
            memory_dir: self.memory_dir.clone(),
            worktrees_dir: self.worktrees_dir.clone(),
            dir_cache: self.dir_cache.clone(),
            mention_index: self.mention_index.clone(),
            origin,
            graduated_checks: Vec::new(),
            lsp_manager: self.lsp_manager.clone(),
            turn_events: Some(self.turn_events.clone()),
            workflow_findings: None,
            abort_flag: Some(self.abort_flag.clone()),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn tool_ctx_for_shares_the_session_abort_flag() {
        let tmp = std::env::temp_dir().join(format!("zesdex-rest-test-{}", uuid::Uuid::new_v4()));
        std::fs::create_dir_all(&tmp).unwrap();
        let state = AppStateRest::new(vec![tmp.clone()], &tmp, tmp.join("memory"));

        let ctx = state.tool_ctx_for(Origin::Main);

        assert!(ctx.abort_flag.is_some());
        assert!(std::sync::Arc::ptr_eq(
            ctx.abort_flag.as_ref().unwrap(),
            &state.abort_flag,
        ));

        std::fs::remove_dir_all(&tmp).ok();
    }
}