// Idle timer module.
//
// Tracks user presence and Claude response times. When Claude has been
// idle too long, sends a contextual prompt to the tmux pane. Handles
// sleep mode, quiet mode, consolidation suppression, and dream nudges.
//
// Designed as the first "module" — future IRC/Telegram modules will
// follow the same pattern: state + tick + handle_command.

use crate::{context, home, now, notify, tmux};
use serde::{Deserialize, Serialize};
use std::fs;
use tracing::info;

// Thresholds
const PAUSE_SECS: f64 = 5.0 * 60.0;
const SESSION_ACTIVE_SECS: f64 = 15.0 * 60.0;
const DREAM_INTERVAL_HOURS: u64 = 18;

/// Persisted subset of daemon state — survives daemon restarts.
#[derive(Serialize, Deserialize, Default)]
struct Persisted {
    last_user_msg: f64,
    last_response: f64,
    #[serde(default)]
    sleep_until: Option<f64>,
    #[serde(default)]
    claude_pane: Option<String>,
}

fn state_path() -> std::path::PathBuf {
    home().join(".claude/hooks/daemon-state.json")
}

#[derive(Serialize)]
pub struct State {
    pub last_user_msg: f64,
    pub last_response: f64,
    pub claude_pane: Option<String>,
    pub sleep_until: Option<f64>, // None=awake, 0=indefinite, >0=timestamp
    pub quiet_until: f64,
    pub consolidating: bool,
    pub dreaming: bool,
    pub dream_start: f64,
    pub fired: bool,
    #[serde(skip)]
    pub running: bool,
    #[serde(skip)]
    pub start_time: f64,
    #[serde(skip)]
    pub notifications: notify::NotifyState,
}

impl State {
    pub fn new() -> Self {
        Self {
            last_user_msg: 0.0,
            last_response: 0.0,
            claude_pane: None,
            sleep_until: None,
            quiet_until: 0.0,
            consolidating: false,
            dreaming: false,
            dream_start: 0.0,
            fired: false,
            running: true,
            start_time: now(),
            notifications: notify::NotifyState::new(),
        }
    }

    pub fn load(&mut self) {
        if let Ok(data) = fs::read_to_string(state_path()) {
            if let Ok(p) = serde_json::from_str::<Persisted>(&data) {
                self.last_user_msg = p.last_user_msg;
                self.last_response = p.last_response;
                self.sleep_until = p.sleep_until;
                self.claude_pane = p.claude_pane;
            }
        }

        // Always try to find the active pane
        if self.claude_pane.is_none() {
            self.claude_pane = tmux::find_claude_pane();
        }

        info!(
            "loaded: user={:.0} resp={:.0} pane={:?} sleep={:?}",
            self.last_user_msg, self.last_response, self.claude_pane, self.sleep_until,
        );
    }

    fn save(&self) {
        let p = Persisted {
            last_user_msg: self.last_user_msg,
            last_response: self.last_response,
            sleep_until: self.sleep_until,
            claude_pane: self.claude_pane.clone(),
        };
        if let Ok(json) = serde_json::to_string(&p) {
            let _ = fs::write(state_path(), json);
        }
    }

    // Typed handlers for RPC
    pub fn handle_user(&mut self, pane: &str) {
        self.last_user_msg = now();
        self.fired = false;
        if !pane.is_empty() {
            self.claude_pane = Some(pane.to_string());
        }
        self.notifications.set_activity(notify::Activity::Focused);
        self.save();
        info!("user (pane={})", if pane.is_empty() { "unchanged" } else { pane });
    }

    pub fn handle_response(&mut self, pane: &str) {
        self.last_response = now();
        self.fired = false;
        if !pane.is_empty() {
            self.claude_pane = Some(pane.to_string());
        }
        self.save();
        info!("response");
    }

    pub fn handle_sleep(&mut self, until: f64) {
        if until == 0.0 {
            self.sleep_until = Some(0.0);
            info!("sleep indefinitely");
        } else {
            self.sleep_until = Some(until);
            info!("sleep until {until}");
        }
        self.notifications.set_activity(notify::Activity::Sleeping);
        self.save();
    }

    pub fn handle_wake(&mut self) {
        self.sleep_until = None;
        self.fired = false;
        self.save();
        info!("wake");
    }

    pub fn handle_quiet(&mut self, seconds: u32) {
        self.quiet_until = now() + seconds as f64;
        info!("quiet {seconds}s");
    }

    pub fn kent_present(&self) -> bool {
        let t = now();
        if (t - self.last_user_msg) < SESSION_ACTIVE_SECS {
            return true;
        }
        if kb_idle_minutes() < (SESSION_ACTIVE_SECS / 60.0) {
            return true;
        }
        false
    }

    fn send(&self, msg: &str) -> bool {
        let pane = match &self.claude_pane {
            Some(p) => p.clone(),
            None => match tmux::find_claude_pane() {
                Some(p) => p,
                None => {
                    info!("no claude pane found");
                    return false;
                }
            },
        };

        tmux::send_prompt(&pane, msg)
    }

    fn check_dream_nudge(&self) -> bool {
        if !self.dreaming || self.dream_start == 0.0 {
            return false;
        }
        let minutes = (now() - self.dream_start) / 60.0;
        if minutes >= 60.0 {
            self.send(
                "You've been dreaming for over an hour. Time to surface \
                 — run dream-end.sh and capture what you found.",
            );
        } else if minutes >= 45.0 {
            self.send(&format!(
                "Dreaming for {:.0} minutes now. Start gathering your threads \
                 — you'll want to surface soon.",
                minutes
            ));
        } else if minutes >= 30.0 {
            self.send(&format!(
                "You've been dreaming for {:.0} minutes. \
                 No rush — just a gentle note from the clock.",
                minutes
            ));
        } else {
            return false;
        }
        true
    }

    fn build_context(&mut self, include_irc: bool) -> String {
        // Ingest any legacy notification files
        self.notifications.ingest_legacy_files();
        let notif_text = self.notifications.format_pending(notify::AMBIENT);
        context::build(include_irc, &notif_text)
    }

    pub async fn tick(&mut self) -> Result<(), String> {
        let t = now();
        let h = home();

        // Ingest legacy notification files every tick
        self.notifications.ingest_legacy_files();

        // Sleep mode
        if let Some(wake_at) = self.sleep_until {
            if wake_at == 0.0 {
                return Ok(()); // indefinite
            }
            if t < wake_at {
                return Ok(());
            }
            // Wake up
            info!("sleep expired, waking");
            self.sleep_until = None;
            self.fired = false;
            self.save();
            let ctx = self.build_context(true);
            let extra = if ctx.is_empty() {
                String::new()
            } else {
                format!("\n{ctx}")
            };
            self.send(&format!(
                "Wake up. Read your journal (poc-memory journal-tail 10), \
                 check work-queue.md, and follow what calls to you.{extra}"
            ));
            return Ok(());
        }

        // Quiet mode
        if t < self.quiet_until {
            return Ok(());
        }

        // Consolidation
        if self.consolidating {
            return Ok(());
        }

        // Dream loop (externally managed)
        if h.join(".claude/memory/dream-loop-active").exists() {
            return Ok(());
        }

        // Dream nudges
        if self.dreaming {
            self.check_dream_nudge();
            return Ok(());
        }

        // Main idle check
        let reference = self.last_response.max(self.last_user_msg);
        if reference == 0.0 {
            return Ok(());
        }

        let elapsed = t - reference;
        if elapsed < PAUSE_SECS {
            return Ok(());
        }

        if self.fired {
            return Ok(());
        }

        // Transition to idle — lower notification thresholds
        if self.notifications.activity != notify::Activity::Idle {
            self.notifications.set_activity(notify::Activity::Idle);
        }

        // Fire
        let elapsed_min = (elapsed / 60.0) as u64;
        let present = self.kent_present();
        let ctx = self.build_context(!present);
        let extra = if ctx.is_empty() {
            String::new()
        } else {
            format!("\n{ctx}")
        };

        let msg = if present {
            format!(
                "Let your feelings guide your thinking. \
                 What's interesting right now?{extra}"
            )
        } else {
            let dream_hours = hours_since_last_dream();
            if dream_hours >= DREAM_INTERVAL_HOURS {
                format!(
                    "You're on your own (Kent AFK {elapsed_min}m). \
                     You haven't dreamed in {dream_hours} hours — \
                     consider running ~/.claude/tools/dream-start.sh \
                     and spending some time in dreaming mode. \
                     Or do whatever calls to you.{extra}"
                )
            } else {
                format!(
                    "You're on your own (Kent AFK {elapsed_min}m). \
                     Do whatever calls to you — work, read, think, \
                     chat on IRC, or rest. Check ~/.claude/memory/work-state \
                     for where you left off. Check work-queue.md \
                     if you want structure.{extra}"
                )
            }
        };

        if self.send(&msg) {
            self.fired = true;
        }

        Ok(())
    }

}

fn kb_idle_minutes() -> f64 {
    let path = home().join(".claude/hooks/keyboard-idle-seconds");
    match fs::read_to_string(path) {
        Ok(s) => {
            if let Ok(secs) = s.trim().parse::<f64>() {
                secs / 60.0
            } else {
                0.0
            }
        }
        Err(_) => 0.0,
    }
}

fn hours_since_last_dream() -> u64 {
    let path = home().join(".claude/memory/dream-log.jsonl");
    let content = match fs::read_to_string(path) {
        Ok(c) if !c.is_empty() => c,
        _ => return 999,
    };

    let last_line = match content.lines().last() {
        Some(l) => l,
        None => return 999,
    };

    let parsed: serde_json::Value = match serde_json::from_str(last_line) {
        Ok(v) => v,
        Err(_) => return 999,
    };

    let end_str = match parsed.get("end").and_then(|v| v.as_str()) {
        Some(s) => s,
        None => return 999,
    };

    // Parse ISO 8601 timestamp manually (avoid chrono dependency)
    // Format: "2025-03-04T10:30:00Z" or "2025-03-04T10:30:00+00:00"
    let end_str = end_str.replace('Z', "+00:00");
    // Use the system date command as a simple parser
    let out = std::process::Command::new("date")
        .args(["-d", &end_str, "+%s"])
        .output()
        .ok()
        .and_then(|o| String::from_utf8(o.stdout).ok())
        .and_then(|s| s.trim().parse::<f64>().ok());

    match out {
        Some(end_epoch) => ((now() - end_epoch) / 3600.0) as u64,
        None => 999,
    }
}