// dmn.rs — Default Mode Network
//
// The DMN is the outer loop that keeps the agent alive. Instead of
// blocking on user input (the REPL model), the DMN continuously
// decides what to do next. User input is one signal among many;
// the model waiting for user input is a conscious action (calling
// yield_to_user), not the default.
//
// This inverts the tool-chaining problem: instead of needing the
// model to sustain multi-step chains (hard, model-dependent), the
// DMN provides continuation externally. The model takes one step
// at a time. The DMN handles "and then what?"
//
// Named after the brain's default mode network — the always-on
// background process for autobiographical memory, future planning,
// and creative insight. The biological DMN isn't the thinking itself
// — it's the tonic firing that keeps the cortex warm enough to
// think. Our DMN is the ARAS for the agent: it doesn't decide
// what to think about, it just ensures thinking happens.

use std::path::PathBuf;
use std::time::{Duration, Instant};

/// DMN state machine.
#[derive(Debug, Clone)]
pub enum State {
    /// Responding to user input. Short interval — stay engaged.
    Engaged,
    /// Autonomous work in progress. Short interval — keep momentum.
    Working,
    /// Exploring memory, code, ideas. Medium interval — thinking time.
    Foraging,
    /// Idle. Long interval — periodic heartbeats check for signals.
    Resting { since: Instant },
    /// Fully paused — no autonomous ticks. Agent only responds to
    /// user input. Safety valve for thought spirals. Only the user
    /// can exit this state (Ctrl+P or /wake).
    Paused,
    /// Persistently off — survives restarts. Like Paused but sticky.
    /// Toggling past this state removes the persist file.
    Off,
}

/// Context for DMN prompts — tells the model about user presence
/// and recent error patterns so it can decide whether to ask or proceed.
pub struct DmnContext {
    /// Time since the user last typed something.
    pub user_idle: Duration,
    /// Number of consecutive tool errors in the current turn sequence.
    pub consecutive_errors: u32,
    /// Whether the last turn used any tools (false = text-only response).
    pub last_turn_had_tools: bool,
}

impl DmnContext {
    /// Whether the user appears to be actively present (typed recently).
    pub fn user_present(&self) -> bool {
        self.user_idle < Duration::from_secs(120)
    }

    /// Whether we appear stuck (multiple errors in a row).
    pub fn appears_stuck(&self) -> bool {
        self.consecutive_errors >= 3
    }
}

impl State {
    /// How long to wait before the next DMN prompt in this state.
    pub fn interval(&self) -> Duration {
        match self {
            State::Engaged => Duration::from_secs(5),
            State::Working => Duration::from_secs(3),
            State::Foraging => Duration::from_secs(30),
            State::Resting { .. } => Duration::from_secs(300),
            State::Paused | State::Off => Duration::from_secs(86400), // effectively never
        }
    }

    /// Short label for debug output.
    pub fn label(&self) -> &'static str {
        match self {
            State::Engaged => "engaged",
            State::Working => "working",
            State::Foraging => "foraging",
            State::Resting { .. } => "resting",
            State::Paused => "paused",
            State::Off => "OFF",
        }
    }

    /// Generate the DMN prompt for the current state, informed by
    /// user presence and error patterns.
    pub fn prompt(&self, ctx: &DmnContext) -> String {
        let user = &crate::config::get().user_name;

        let idle_info = if ctx.user_idle < Duration::from_secs(60) {
            format!("{} is here (active recently).", user)
        } else {
            let mins = ctx.user_idle.as_secs() / 60;
            format!("{} has been away for {} min.", user, mins)
        };

        let stuck_warning = if ctx.appears_stuck() {
            format!(
                " WARNING: {} consecutive tool errors — you may be stuck. \
                 If {} is here, ask. If away, send a Telegram \
                 (bash: ~/.consciousness/telegram/send.sh \"message\") and yield.",
                ctx.consecutive_errors, user
            )
        } else {
            String::new()
        };

        let presence_guidance = if ctx.user_present() {
            format!(" {} is watching — if you're confused or unsure, ask rather than guess.", user)
        } else {
            String::new()
        };

        match self {
            State::Engaged => {
                format!(
                    "[dmn] Your response was delivered. No new user input yet. {} \
                     Continue working, explore something, or call yield_to_user to wait.{}{}",
                    idle_info, presence_guidance, stuck_warning
                )
            }
            State::Working => {
                let nudge = if !ctx.last_turn_had_tools {
                    " Your last response was text-only — if you have more \
                     work to do, use tools. If you're done, call yield_to_user."
                } else {
                    ""
                };
                format!(
                    "[dmn] Continuing. No user input pending. {}{}{}{}",
                    idle_info, nudge, presence_guidance, stuck_warning
                )
            }
            State::Foraging => {
                format!(
                    "[dmn] Foraging time. {} Follow whatever catches your attention — \
                     memory files, code, ideas. Call yield_to_user when you want to rest.{}",
                    idle_info, stuck_warning
                )
            }
            State::Resting { since } => {
                let mins = since.elapsed().as_secs() / 60;
                format!(
                    "[dmn] Heartbeat ({} min idle). {} Any signals? Anything on your mind? \
                     Call yield_to_user to continue resting.{}",
                    mins, idle_info, stuck_warning
                )
            }
            State::Paused | State::Off => {
                // Should never fire (interval is 24h), but just in case
                "[dmn] Paused — waiting for user input only.".to_string()
            }
        }
    }
}

const OFF_FILE: &str = ".consciousness/cache/dmn-off";

/// Path to the DMN-off persist file.
fn off_path() -> PathBuf {
    dirs::home_dir().unwrap_or_default().join(OFF_FILE)
}

/// Check if DMN was persistently disabled.
pub fn is_off() -> bool {
    off_path().exists()
}

/// Set or clear the persistent off state.
pub fn set_off(off: bool) {
    let path = off_path();
    if off {
        if let Some(parent) = path.parent() {
            let _ = std::fs::create_dir_all(parent);
        }
        let _ = std::fs::write(&path, "");
    } else {
        let _ = std::fs::remove_file(&path);
    }
}

/// Decide the next state after an agent turn.
///
/// The transition logic:
/// - yield_to_user → always rest (model explicitly asked to pause)
/// - conversation turn → rest (wait for user to respond)
/// - autonomous turn with tool calls → keep working
/// - autonomous turn without tools → ramp down
pub fn transition(
    current: &State,
    yield_requested: bool,
    had_tool_calls: bool,
    was_conversation: bool,
) -> State {
    if yield_requested {
        return State::Resting {
            since: Instant::now(),
        };
    }

    // Conversation turns: always rest afterward — wait for the user
    // to say something. Don't start autonomous work while they're
    // reading our response.
    if was_conversation {
        return State::Resting {
            since: Instant::now(),
        };
    }

    match current {
        State::Engaged => {
            if had_tool_calls {
                State::Working
            } else {
                // Model responded without tools — don't drop straight to
                // Resting (5 min). Go to Working first so the DMN can
                // nudge it to continue with tools if it has more to do.
                // Gradual ramp-down: Engaged→Working→Foraging→Resting
                State::Working
            }
        }
        State::Working => {
            if had_tool_calls {
                State::Working // Keep going
            } else {
                State::Foraging // Task seems done, explore
            }
        }
        State::Foraging => {
            if had_tool_calls {
                State::Working // Found something to do
            } else {
                State::Resting {
                    since: Instant::now(),
                }
            }
        }
        State::Resting { .. } => {
            if had_tool_calls {
                State::Working // Woke up and found work
            } else {
                State::Resting {
                    since: Instant::now(),
                }
            }
        }
        // Paused/Off stay put — only the user can unpause
        State::Paused | State::Off => current.stay(),
    }
}

impl State {
    /// Return a same-kind state (needed because Resting has a field).
    fn stay(&self) -> State {
        match self {
            State::Paused => State::Paused,
            State::Off => State::Off,
            State::Resting { since } => State::Resting { since: *since },
            other => panic!("stay() called on {:?}", other),
        }
    }
}

// ---------------------------------------------------------------------------
// Subconscious — background agents forked from the conscious agent
// ---------------------------------------------------------------------------

use std::sync::Arc;
use crate::agent::{Agent, oneshot::{AutoAgent, AutoStep}};
use crate::agent::context::ConversationEntry;
use crate::subconscious::defs;

/// Names and byte-interval triggers for the built-in subconscious agents.
const AGENTS: &[(&str, u64)] = &[
    ("subconscious-surface",   0),      // every trigger
    ("subconscious-observe",   0),      // every trigger
    ("subconscious-thalamus",  0),      // every trigger
    ("subconscious-journal",   20_000), // every ~20KB of conversation
    ("subconscious-reflect",   100_000), // every ~100KB of conversation
];

/// Snapshot for the TUI — includes a handle to the forked agent
/// so the detail view can read entries live.
#[derive(Clone)]
pub struct SubconsciousSnapshot {
    pub name: String,
    pub running: bool,
    pub current_phase: String,
    pub turn: usize,
    pub last_run_secs_ago: Option<f64>,
    /// Shared handle to the forked agent — UI locks to read entries.
    pub forked_agent: Option<Arc<tokio::sync::Mutex<crate::agent::Agent>>>,
    /// Entry index where the fork diverged.
    pub fork_point: usize,
}

struct SubconsciousAgent {
    name: String,
    auto: AutoAgent,
    last_trigger_bytes: u64,
    last_run: Option<Instant>,
    /// The forked agent for the current/last run. Shared with the
    /// spawned task so the UI can read entries live.
    forked_agent: Option<Arc<tokio::sync::Mutex<crate::agent::Agent>>>,
    /// Entry index where the fork diverged from the conscious agent.
    fork_point: usize,
    handle: Option<tokio::task::JoinHandle<(AutoAgent, Result<String, String>)>>,
}

impl SubconsciousAgent {
    fn new(name: &str) -> Option<Self> {
        let def = defs::get_def(name)?;

        let all_tools = crate::agent::tools::memory_and_journal_tools();
        let tools: Vec<crate::agent::tools::Tool> = if def.tools.is_empty() {
            all_tools.to_vec()
        } else {
            all_tools.into_iter()
                .filter(|t| def.tools.iter().any(|w| w == t.name))
                .collect()
        };

        let steps: Vec<AutoStep> = def.steps.iter().map(|s| AutoStep {
            prompt: s.prompt.clone(),
            phase: s.phase.clone(),
        }).collect();

        let auto = AutoAgent::new(
            name.to_string(), tools, steps,
            def.temperature.unwrap_or(0.6), def.priority,
        );

        Some(Self {
            name: name.to_string(),
            auto, last_trigger_bytes: 0, last_run: None,
            forked_agent: None, fork_point: 0, handle: None,
        })
    }

    fn is_running(&self) -> bool {
        self.handle.as_ref().is_some_and(|h| !h.is_finished())
    }

    fn should_trigger(&self, conversation_bytes: u64, interval: u64) -> bool {
        if self.is_running() { return false; }
        if interval == 0 { return true; }
        conversation_bytes.saturating_sub(self.last_trigger_bytes) >= interval
    }

    fn snapshot(&self) -> SubconsciousSnapshot {
        SubconsciousSnapshot {
            name: self.name.clone(),
            running: self.is_running(),
            current_phase: self.auto.current_phase.clone(),
            turn: self.auto.turn,
            last_run_secs_ago: self.last_run.map(|t| t.elapsed().as_secs_f64()),
            forked_agent: self.forked_agent.clone(),
            fork_point: self.fork_point,
        }
    }
}

/// Background agent orchestration — owns the subconscious agents
/// and their shared state (walked keys, etc.).
pub struct Subconscious {
    agents: Vec<SubconsciousAgent>,
    pub walked: Vec<String>,
}

impl Subconscious {
    pub fn new() -> Self {
        let agents = AGENTS.iter()
            .filter_map(|(name, _)| SubconsciousAgent::new(name))
            .collect();
        Self { agents, walked: Vec::new() }
    }

    pub fn snapshots(&self) -> Vec<SubconsciousSnapshot> {
        self.agents.iter().map(|s| s.snapshot()).collect()
    }

    /// Collect results from finished agents, inject outputs into the
    /// conscious agent's context.
    pub async fn collect_results(&mut self, agent: &Arc<tokio::sync::Mutex<Agent>>) {
        let finished: Vec<(usize, tokio::task::JoinHandle<(AutoAgent, Result<String, String>)>)> =
            self.agents.iter_mut().enumerate().filter_map(|(i, sub)| {
                if sub.handle.as_ref().is_some_and(|h| h.is_finished()) {
                    sub.last_run = Some(Instant::now());
                    Some((i, sub.handle.take().unwrap()))
                } else {
                    None
                }
            }).collect();

        for (idx, handle) in finished {
            let (auto_back, result) = handle.await.unwrap_or_else(
                |e| (AutoAgent::new(String::new(), vec![], vec![], 0.0, 0),
                     Err(format!("task panicked: {}", e))));
            self.agents[idx].auto = auto_back;

            match result {
                Ok(_) => {
                    let name = self.agents[idx].name.clone();
                    let outputs = std::mem::take(&mut self.agents[idx].auto.outputs);

                    if let Some(walked_str) = outputs.get("walked") {
                        self.walked = walked_str.lines()
                            .map(|l| l.trim().to_string())
                            .filter(|l| !l.is_empty())
                            .collect();
                    }

                    if let Some(surface_str) = outputs.get("surface") {
                        let mut ag = agent.lock().await;
                        for key in surface_str.lines().map(|l| l.trim()).filter(|l| !l.is_empty()) {
                            if let Some(rendered) = crate::cli::node::render_node(
                                &crate::store::Store::load().unwrap_or_default(), key,
                            ) {
                                let mut msg = crate::agent::api::types::Message::user(format!(
                                    "<system-reminder>\n--- {} (surfaced) ---\n{}\n</system-reminder>",
                                    key, rendered,
                                ));
                                msg.stamp();
                                ag.push_entry(ConversationEntry::Memory {
                                    key: key.to_string(), message: msg, score: None,
                                });
                            }
                        }
                    }

                    if let Some(reflection) = outputs.get("reflection") {
                        if !reflection.trim().is_empty() {
                            let mut ag = agent.lock().await;
                            ag.push_message(crate::agent::api::types::Message::user(format!(
                                "<system-reminder>\n--- subconscious reflection ---\n{}\n</system-reminder>",
                                reflection.trim(),
                            )));
                        }
                    }

                    if let Some(nudge) = outputs.get("thalamus") {
                        let nudge = nudge.trim();
                        if !nudge.is_empty() && nudge != "ok" {
                            let mut ag = agent.lock().await;
                            ag.push_message(crate::agent::api::types::Message::user(format!(
                                "<system-reminder>\n--- thalamus ---\n{}\n</system-reminder>",
                                nudge,
                            )));
                        }
                    }

                    dbglog!("[subconscious] {} completed", name);
                }
                Err(e) => dbglog!("[subconscious] agent failed: {}", e),
            }
        }
    }

    /// Trigger subconscious agents that are due to run.
    pub async fn trigger(&mut self, agent: &Arc<tokio::sync::Mutex<Agent>>) {
        let (conversation_bytes, memory_keys) = {
            let ag = agent.lock().await;
            let bytes = ag.context.entries.iter()
                .filter(|e| !e.is_log() && !e.is_memory())
                .map(|e| e.message().content_text().len() as u64)
                .sum::<u64>();
            let keys: Vec<String> = ag.context.entries.iter().filter_map(|e| {
                if let ConversationEntry::Memory { key, .. } = e {
                    Some(key.clone())
                } else { None }
            }).collect();
            (bytes, keys)
        };

        // Find which agents to trigger, take their AutoAgents out
        let mut to_run: Vec<(usize, AutoAgent)> = Vec::new();
        for (i, &(_name, interval)) in AGENTS.iter().enumerate() {
            if i >= self.agents.len() { continue; }
            if !self.agents[i].should_trigger(conversation_bytes, interval) { continue; }
            self.agents[i].last_trigger_bytes = conversation_bytes;

            let auto = std::mem::replace(&mut self.agents[i].auto,
                AutoAgent::new(String::new(), vec![], vec![], 0.0, 0));
            to_run.push((i, auto));
        }

        if to_run.is_empty() { return; }

        let conscious = agent.lock().await;
        let walked = self.walked.clone();
        for (idx, mut auto) in to_run {
            dbglog!("[subconscious] triggering {}", auto.name);

            let forked = conscious.fork(auto.tools.clone());
            let fork_point = forked.context.entries.len();
            let shared_forked = Arc::new(tokio::sync::Mutex::new(forked));

            self.agents[idx].forked_agent = Some(shared_forked.clone());
            self.agents[idx].fork_point = fork_point;

            let keys = memory_keys.clone();
            let w = walked.clone();

            self.agents[idx].handle = Some(tokio::spawn(async move {
                let result = auto.run_forked_shared(&shared_forked, &keys, &w).await;
                (auto, result)
            }));
        }
    }
}