//! `ContainerView` + the snapshot builder that turns
//! `nixos-container list` (plus per-agent state on disk) into the row
//! shape the dashboard renders. Extracted from `dashboard.rs` so the
//! coordinator's rescan-and-emit helper can build the same view and
//! diff against the last snapshot to fire
//! `ContainerStateChanged` / `ContainerRemoved` events.

use std::collections::HashMap;
use std::path::Path;

use rusqlite::Connection;
use serde::{Deserialize, Serialize};

use crate::coordinator::Coordinator;
use crate::lifecycle::{self, AGENT_PREFIX, MANAGER_NAME};

/// An agent-declared extra navigation link surfaced on the dashboard card.
/// Written by the `hive-dashboard-links` NixOS oneshot into
/// `{state_dir}/hyperhive-dashboard-links.json` and read by `build_all`.
#[derive(Serialize, Deserialize, Clone, PartialEq, Eq, Debug, Default)]
pub struct DashboardLink {
    pub label: String,
    #[serde(default)]
    pub icon: String,
    pub url: String,
}

#[derive(Serialize, Clone, PartialEq, Eq, Debug)]
#[allow(clippy::struct_excessive_bools)]
pub struct ContainerView {
    /// Logical agent name (no `h-` prefix). Used in action URLs.
    pub name: String,
    /// Container name as nixos-container sees it (`h-foo`, `hm1nd`).
    pub container: String,
    pub is_manager: bool,
    pub port: u16,
    pub running: bool,
    pub needs_update: bool,
    pub needs_login: bool,
    /// First 12 chars of the sha the meta flake currently has locked
    /// for this agent's input.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub deployed_sha: Option<String>,
    /// Count of this agent's pending reminders. Computed during
    /// `build_all` via `Broker::count_pending_reminders_for`; the
    /// dashboard renders a small chip when > 0. Updates with the
    /// 10s `crash_watch` rescan + every container mutation site;
    /// not real-time on remind/cancel-reminder but close enough.
    #[serde(default)]
    pub pending_reminders: u64,
    /// Context-window size (prompt tokens) from the agent's most recent
    /// completed turn, read directly from the turn-stats `SQLite`.
    /// `None` when the file is absent or the agent has no turns yet.
    /// Stale by up to one crash-watch cycle (~10s); good enough for
    /// the "which agent is close to the window?" dashboard glance.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub ctx_tokens: Option<u64>,
    /// Context-window size (tokens) for the model this agent ran on its
    /// most recent turn — the model name from the last turn-stats row
    /// resolved against the host's per-model `contextWindowTokens`
    /// config. Lets the dashboard derive the ctx badge thresholds
    /// (75% / 50% of the window, matching the harness compaction
    /// watermarks) instead of hardcoding them. `None` when the agent
    /// has no turns yet or no config key matches the model. (issue #66)
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub context_window_tokens: Option<u64>,
    /// True while the harness is parked after an API rate-limit response.
    /// Detected via the sentinel file `{state_dir}/hyperhive-rate-limited`
    /// that the harness writes in `Bus::emit_status("rate_limited")` and
    /// removes when it resumes. Stale by up to one crash-watch cycle.
    #[serde(default)]
    pub rate_limited: bool,
    /// Extra navigation links declared by the agent via
    /// `hyperhive.dashboardLinks` in `agent.nix`. Written to
    /// `{state_dir}/hyperhive-dashboard-links.json` by the
    /// `hive-dashboard-links` oneshot at container boot. Empty when
    /// the file is absent or the agent declares no links.
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub extra_links: Vec<DashboardLink>,
    /// Free-text status set by the agent via `mcp__hyperhive__set_status`.
    /// Persisted to `{state_dir}/hyperhive-status`. `None` when the file
    /// is absent or empty — the agent hasn't set one yet.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub status_text: Option<String>,
    /// Unix timestamp (seconds since epoch) when the status was last written.
    /// Derived from the `hyperhive-status` file's mtime. `None` when no
    /// status is set.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub status_set_at: Option<i64>,
}

/// Build the full container list. Wraps `lifecycle::list()` and
/// resolves every per-agent attribute the dashboard surfaces.
pub async fn build_all(coord: &Coordinator) -> Vec<ContainerView> {
    let raw = lifecycle::list().await.unwrap_or_default();
    let locked = read_meta_locked_revs();
    let mut out = Vec::new();
    for c in &raw {
        let (logical, is_manager) = if c == MANAGER_NAME {
            (MANAGER_NAME.to_owned(), true)
        } else if let Some(n) = c.strip_prefix(AGENT_PREFIX) {
            (n.to_owned(), false)
        } else {
            continue;
        };
        let deployed_full = locked.get(&format!("agent-{logical}")).map(std::string::String::as_str);
        let needs_update = crate::auto_update::agent_config_pending(&logical, deployed_full);
        let needs_login =
            !is_manager && !claude_has_session(&Coordinator::agent_claude_dir(&logical));
        let deployed_sha = deployed_full.map(|s| s[..s.len().min(12)].to_owned());
        // Recipient name the broker uses for this agent — sub-agents
        // are addressed by logical name, the manager by the
        // MANAGER_AGENT constant. Mirrors the rest of the broker
        // surface so the count matches what `mcp__hyperhive__remind`
        // queued.
        let reminder_recipient = if is_manager {
            hive_sh4re::MANAGER_AGENT
        } else {
            logical.as_str()
        };
        let pending_reminders = coord
            .broker
            .count_pending_reminders_for(reminder_recipient)
            .unwrap_or(0);
        let last_turn = read_last_turn(&logical);
        let ctx_tokens = last_turn.as_ref().map(|(toks, _)| *toks);
        let context_window_tokens = last_turn
            .as_ref()
            .and_then(|(_, model)| resolve_ctx_window(model, &coord.context_window_tokens));
        let rate_limited = is_rate_limited(&logical);
        let extra_links = read_dashboard_links(&logical);
        let (status_text, status_set_at) = read_status(&logical);
        out.push(ContainerView {
            port: lifecycle::agent_web_port(&logical),
            running: lifecycle::is_running(&logical).await,
            container: c.clone(),
            name: logical,
            is_manager,
            needs_update,
            needs_login,
            deployed_sha,
            pending_reminders,
            ctx_tokens,
            context_window_tokens,
            rate_limited,
            extra_links,
            status_text,
            status_set_at,
        });
    }
    out
}

/// Host-side mirror of `hive_ag3nt::login::has_session`. Returns true
/// if the agent's bound `~/.claude/` dir on disk contains any regular
/// file. Reads each `build_all()` so a login driven from the agent's
/// own web UI reflects on the next snapshot.
pub fn claude_has_session(dir: &Path) -> bool {
    let Ok(entries) = std::fs::read_dir(dir) else {
        return false;
    };
    entries
        .flatten()
        .any(|e| e.file_type().is_ok_and(|t| t.is_file()))
}

/// Read agent-declared extra dashboard links from
/// `{state_dir}/hyperhive-dashboard-links.json`. Returns an empty vec when
/// the file is absent, empty, or unparseable — best-effort, never panics.
fn read_dashboard_links(name: &str) -> Vec<DashboardLink> {
    let path = Coordinator::agent_notes_dir(name).join("hyperhive-dashboard-links.json");
    let text = match std::fs::read_to_string(&path) {
        Ok(t) if !t.trim().is_empty() => t,
        _ => return Vec::new(),
    };
    serde_json::from_str::<Vec<DashboardLink>>(&text).unwrap_or_default()
}

/// Returns true if the agent's harness is currently parked after an API
/// rate-limit response. Detected via the sentinel file written by
/// `hive_ag3nt::events::Bus::emit_status("rate_limited")`.
fn is_rate_limited(name: &str) -> bool {
    Coordinator::agent_notes_dir(name)
        .join("hyperhive-rate-limited")
        .exists()
}

/// Read the agent's free-text status and the Unix timestamp when it was last set
/// (derived from the file's mtime). Returns `(None, None)` when the file is absent
/// or empty. `pub` so `agent_server` and `manager_server` can populate `AgentMeta`.
pub fn read_agent_status(name: &str) -> (Option<String>, Option<i64>) {
    let path = Coordinator::agent_notes_dir(name).join("hyperhive-status");
    let meta = std::fs::metadata(&path).ok();
    let s = std::fs::read_to_string(&path).ok();
    let text = s.as_deref().map(str::trim).filter(|t| !t.is_empty()).map(str::to_owned);
    let mtime = meta.and_then(|m| {
        m.modified().ok().and_then(|t| {
            t.duration_since(std::time::UNIX_EPOCH).ok()
                .and_then(|d| i64::try_from(d.as_secs()).ok())
        })
    });
    if text.is_none() { (None, None) } else { (text, mtime) }
}

fn read_status(name: &str) -> (Option<String>, Option<i64>) {
    read_agent_status(name)
}

/// Read the agent's most recent completed turn from its turn-stats
/// `SQLite`: the context-window size (prompt tokens) and the model name.
/// Returns `None` when the file is absent or has no rows. Best-effort
/// — any database error silently yields `None` so a missing or
/// corrupt file never blocks `build_all`.
///
/// Context tokens sum the prompt-side fields (`last_input_tokens`,
/// `last_cache_read_input_tokens`, `last_cache_creation_input_tokens`),
/// mirroring `hive_ag3nt::events::TokenUsage::context_tokens`.
fn read_last_turn(name: &str) -> Option<(u64, String)> {
    let path = Coordinator::agent_notes_dir(name).join("hyperhive-turn-stats.sqlite");
    let conn = Connection::open_with_flags(
        &path,
        rusqlite::OpenFlags::SQLITE_OPEN_READ_ONLY,
    )
    .ok()?;
    conn.query_row(
        "SELECT last_input_tokens + last_cache_read_input_tokens + last_cache_creation_input_tokens, model \
         FROM turn_stats ORDER BY started_at DESC LIMIT 1",
        [],
        |row| Ok((row.get::<_, i64>(0)?, row.get::<_, String>(1)?)),
    )
    .ok()
    .and_then(|(toks, model)| Some((u64::try_from(toks).ok()?, model)))
}

/// Resolve a model name to its context-window size using the host's
/// per-model `contextWindowTokens` config. Mirrors the harness's
/// `events::context_window_tokens` substring match: the first config
/// key (lowercased, non-empty) that is a substring of the lowercased
/// model name wins. `None` when nothing matches.
fn resolve_ctx_window(model: &str, per_model: &HashMap<String, u64>) -> Option<u64> {
    let m = model.to_ascii_lowercase();
    per_model
        .iter()
        .find(|(key, _)| {
            let k = key.to_ascii_lowercase();
            !k.is_empty() && m.contains(&k)
        })
        .map(|(_, &tokens)| tokens)
}

/// Map of `agent-<n>` → locked sha from meta's flake.lock. Used to
/// render the `deployed:<sha12>` chip per container row.
fn read_meta_locked_revs() -> HashMap<String, String> {
    let mut out = HashMap::new();
    let Ok(raw) = std::fs::read_to_string("/var/lib/hyperhive/meta/flake.lock") else {
        return out;
    };
    let Ok(json) = serde_json::from_str::<serde_json::Value>(&raw) else {
        return out;
    };
    let Some(nodes) = json.get("nodes").and_then(|v| v.as_object()) else {
        return out;
    };
    let Some(root_name) = json.get("root").and_then(|v| v.as_str()) else {
        return out;
    };
    let Some(root_inputs) = nodes
        .get(root_name)
        .and_then(|n| n.get("inputs"))
        .and_then(|v| v.as_object())
    else {
        return out;
    };
    for alias in root_inputs.keys() {
        let target_name = match root_inputs.get(alias) {
            Some(serde_json::Value::String(s)) => s.clone(),
            _ => continue,
        };
        if let Some(rev) = nodes
            .get(&target_name)
            .and_then(|n| n.get("locked"))
            .and_then(|v| v.get("rev"))
            .and_then(|v| v.as_str())
        {
            out.insert(alias.clone(), rev.to_owned());
        }
    }
    out
}

#[cfg(test)]
mod tests {
    use super::resolve_ctx_window;
    use std::collections::HashMap;

    fn cfg() -> HashMap<String, u64> {
        [
            ("haiku".to_owned(), 200_000),
            ("sonnet".to_owned(), 1_000_000),
            ("opus".to_owned(), 1_000_000),
        ]
        .into_iter()
        .collect()
    }

    #[test]
    fn resolves_family_substring() {
        assert_eq!(resolve_ctx_window("claude-3-5-haiku-20241022", &cfg()), Some(200_000));
        assert_eq!(resolve_ctx_window("claude-sonnet-4-5", &cfg()), Some(1_000_000));
        assert_eq!(resolve_ctx_window("claude-opus-4-1", &cfg()), Some(1_000_000));
    }

    #[test]
    fn resolution_is_case_insensitive() {
        assert_eq!(resolve_ctx_window("Claude-Sonnet-4", &cfg()), Some(1_000_000));
    }

    #[test]
    fn unknown_model_yields_none() {
        assert_eq!(resolve_ctx_window("some-other-llm", &cfg()), None);
    }

    #[test]
    fn empty_config_yields_none() {
        assert_eq!(resolve_ctx_window("claude-3-5-haiku", &HashMap::new()), None);
    }

    #[test]
    fn empty_key_is_skipped() {
        let mut m = HashMap::new();
        m.insert(String::new(), 999);
        assert_eq!(resolve_ctx_window("claude-3-5-haiku", &m), None);
    }
}