//! `/api/state` + `/api/dashboard-state` snapshot builders.

use axum::extract::State;
use serde::Serialize;

use crate::login::LoginState;
use crate::login_session::drop_if_finished;

use super::AppState;

pub(super) async fn api_state(State(state): State<AppState>) -> axum::Json<StateSnapshot> {
    // Capture seq *before* any reads so the dedupe contract is
    // "events with seq > snapshot.seq are post-snapshot, never missed."
    let seq = state.bus.current_seq();
    drop_if_finished(&state.session);
    let login = *state.login.lock().unwrap();
    let session_snapshot = state.session.lock().unwrap().clone();
    let (status, session_view) = match (login, session_snapshot) {
        (LoginState::Online, _) if state.bus.is_rate_limited() => ("rate_limited", None),
        (LoginState::Online, _) => ("online", None),
        (LoginState::NeedsLogin, None) => ("needs_login_idle", None),
        (LoginState::NeedsLogin, Some(s)) => (
            "needs_login_in_progress",
            Some(SessionView {
                url: s.url(),
                output: s.output(),
                finished: s.finished(),
                exit_note: s.exit_note(),
            }),
        ),
    };
    let dashboard_port = std::env::var("HIVE_DASHBOARD_PORT")
        .ok()
        .and_then(|s| s.parse::<u16>().ok())
        .unwrap_or(7000);
    let inbox = recent_inbox(&state.socket).await;
    let (turn_state, turn_state_since) = state.bus.state_snapshot();
    let model = state.bus.model();
    let context_window_tokens = state.bus.effective_context_window(&model);
    let ctx_usage = state.bus.last_ctx_usage();
    let cost_usage = state.bus.last_cost_usage();
    let effort = state.bus.effort();
    axum::Json(StateSnapshot {
        seq,
        label: state.label.clone(),
        qualified_label: crate::identity::qualify(&state.label),
        dashboard_port,
        status,
        session: session_view,
        inbox,
        turn_state,
        turn_state_since,
        model,
        context_window_tokens,
        ctx_usage,
        cost_usage,
        links: agent_links(&state.label, state.gui_vnc_port.is_some()),
        forge_public_url: std::env::var("HIVE_FORGE_PUBLIC_URL")
            .ok()
            .filter(|s| !s.is_empty()),
        hive_name: crate::identity::hive_name(),
        swarm_name: crate::identity::swarm_name(),
        available_models: available_models(),
        effort,
        available_efforts: crate::harness_state::EFFORT_LEVELS
            .iter()
            .map(ToString::to_string)
            .collect(),
    })
}

/// Lean snapshot of the agent-owned fields that the dashboard card
/// needs. Served at `GET /api/dashboard-state` (accessible through the
/// gateway at `/agent/<name>/api/dashboard-state`). The dashboard
/// fetches this once per running agent to get fresh, agent-authoritative
/// values instead of relying on hive-c0re's periodic file-reads.
///
/// Structural fields (running, `needs_update`, `deployed_sha`, parent, …)
/// continue to come from hive-c0re's `/api/state`; this endpoint covers
/// only the fields the agent itself is the source of truth for.
pub(super) async fn api_dashboard_state(
    State(state): State<AppState>,
) -> axum::Json<DashboardState> {
    let (status_text, status_set_at) = read_own_status();
    let rate_limited = state.bus.is_rate_limited();
    let model = state.bus.model();
    let context_window_tokens = state.bus.effective_context_window(&model);
    // Full context-window size = input + cache-read + cache-creation. Using
    // raw `input_tokens` here reported only the *uncached* sliver, which is
    // ~0 once prompt caching kicks in — so every card showed `ctx·0k`. Match
    // the agent page (which ships the whole `ctx_usage` and sums it) and the
    // cache-TTL logic in turn.rs, both of which use `context_tokens()`.
    let ctx_tokens = state.bus.last_ctx_usage().map(|u| u.context_tokens());
    axum::Json(DashboardState {
        status_text,
        status_set_at,
        ctx_tokens,
        context_window_tokens,
        rate_limited,
        links: agent_links(&state.label, state.gui_vnc_port.is_some()),
    })
}

#[derive(Serialize)]
pub(super) struct StateSnapshot {
    /// Bus seq at the moment this snapshot was assembled. Clients dedupe
    /// their buffered SSE traffic against this value: events with
    /// `seq <= snapshot.seq` are already reflected (or pre-date the
    /// snapshot); `seq > snapshot.seq` is post-snapshot. Reset to 0 on
    /// harness restart — clients treat reconnect as a fresh world.
    seq: u64,
    label: String,
    /// Hive-qualified long name (`${label}@${hyperhive.domain}`) when
    /// the host has been configured for a multi-hive swarm; falls back
    /// to the short label when the hive domain env var is unset.
    /// The frontend uses this for the page title / agent self-introduction;
    /// when it equals `label`, the page renders the short form unchanged.
    qualified_label: String,
    dashboard_port: u16,
    /// `"online"` | `"rate_limited"` | `"needs_login_idle"` | `"needs_login_in_progress"`.
    status: &'static str,
    /// Present when `status == "needs_login_in_progress"`.
    session: Option<SessionView>,
    /// Last N messages addressed to this agent, newest-first. Pulled
    /// from the broker via the per-agent socket on each render.
    /// Empty on transport failure.
    inbox: Vec<hive_sh4re::inbox::InboxRow>,
    /// Authoritative turn-loop state from the harness and the unix
    /// timestamp the state was entered. The JS computes the age
    /// client-side off this rather than tracking it from SSE events.
    turn_state: crate::events::TurnState,
    turn_state_since: i64,
    /// Currently-active claude model name. Reflected on the page so
    /// the operator can see what they just switched to (and what's
    /// in flight). Mutable at runtime via `POST /api/model`.
    model: String,
    /// Effective context-window token budget for the current model.
    /// Primary source: API-reported `modelUsage.*.contextWindow` from
    /// the last result event (authoritative per-inference active window).
    /// Falls back to `HIVE_CONTEXT_WINDOW_TOKENS_*` env vars, then 200 000.
    /// Consumers (e.g. dashboard badge) use this to render ctx-usage %.
    context_window_tokens: u64,
    /// Last-inference token usage from the most recent completed
    /// turn — represents the current context-window size at turn-end.
    /// `null` until the first turn finishes.
    ctx_usage: Option<hive_claude::TokenUsage>,
    /// Cumulative token usage across the most recent turn's inferences
    /// (cost signal). `null` until the first turn finishes.
    cost_usage: Option<hive_claude::TokenUsage>,
    /// Navigation links for this agent page. Also served via
    /// `DashboardState.links` (`GET /api/dashboard-state`) for the
    /// dashboard card's icon strip. Both are produced by `agent_links()`
    /// — single source of truth. See [`docs/web-ui/dashboard.md::Container row`]
    /// for the frontend resolver + which links appear in which conditions.
    links: Vec<AgentLink>,
    /// Public URL of the forge (e.g.
    /// `"https://forge.pr1ma.darkest.space"`). Sourced from
    /// `HIVE_FORGE_PUBLIC_URL` (set from `services.hyperhive.forge.
    /// publicUrl`); `None` when unset. The frontend uses this to build
    /// forge nav-strip links, and **hides** the forge link entirely
    /// when absent rather than guessing `<hostname>:3000`.
    forge_public_url: Option<String>,
    /// Human name of this hive instance (e.g. `"pr1ma"`). Sourced
    /// from `HYPERHIVE_HIVE_NAME`; `None` when unset. The frontend
    /// uses this for the page `<title>` and header label so browser
    /// tabs disambiguate when multiple hives are open in parallel.
    hive_name: Option<String>,
    /// Human name of the swarm (e.g. `"constellat1on"`). Sourced from
    /// `HYPERHIVE_SWARM_NAME`; `None` when unset.
    swarm_name: Option<String>,
    /// Ordered list of model short-names the operator has declared as
    /// available on this hive. Sourced from `HIVE_AVAILABLE_MODELS`
    /// (comma-separated, set by `services.hyperhive.availableModels`).
    /// Falls back to `["haiku", "sonnet", "opus"]` when the env var is
    /// absent or empty. The frontend model quick-picker renders one button
    /// per entry in this list, so operators can add new models or drop
    /// ones they don't want without touching the frontend code.
    available_models: Vec<String>,
    /// Currently-active claude effort level. Reflected on the page so the
    /// operator's effort picker shows the live selection. Mutable at
    /// runtime via `POST /api/effort`; applies on the next session.
    effort: String,
    /// Selectable effort levels for the picker, ascending. Fixed set
    /// (`low`, `medium`, `high`, `xhigh`, `max`) — sourced from
    /// [`crate::harness_state::EFFORT_LEVELS`], not operator-configurable like
    /// `available_models`. The frontend renders one button per entry.
    available_efforts: Vec<String>,
}

#[derive(Serialize)]
struct SessionView {
    /// First `https://…` claude emitted on stdout, if any.
    url: Option<String>,
    /// Accumulated stdout + stderr.
    output: String,
    finished: bool,
    exit_note: Option<String>,
}

/// One navigation link in the agent page header row. The same JSON
/// shape appears in both `StateSnapshot.links` (`GET /api/state`,
/// per-agent page) and `DashboardState.links` (`GET /api/dashboard-state`,
/// dashboard card icon strip). `agent_links()` is the single source
/// of truth for what links an agent exposes.
#[derive(Serialize)]
struct AgentLink {
    /// `kind = Container | Forge` → path; `kind = External` → full URL.
    /// The frontend prepends the right base before rendering.
    url: String,
    icon: String,
    label: String,
    kind: AgentLinkKind,
}

/// Resolution hint for `AgentLink.url`. The agent backend can't know
/// which hostname the browser sees (especially when the dashboard
/// proxies the call from a different origin), so it labels each link
/// and lets the frontend prepend the right base.
#[derive(Serialize, Clone, Copy)]
#[serde(rename_all = "snake_case")]
enum AgentLinkKind {
    /// `url` is a path on the agent's container web UI (`/stats`,
    /// `/screen`). Agent page: same-origin path. Dashboard:
    /// `http://<host>:<container.port><url>`.
    Container,
    /// `url` is a path on the local Forgejo (`/<label>`,
    /// `/agent-configs/<label>`). Both surfaces:
    /// `http://<host>:3000<url>`.
    Forge,
    /// `url` is already a fully-qualified absolute URL — use as-is.
    /// Agent-declared `hyperhive.dashboardLinks` extras arrive here.
    External,
}

#[derive(serde::Serialize)]
pub(super) struct DashboardState {
    /// Free-text status set by `set_status`, read directly from the
    /// `hyperhive-status` file the harness writes. `None` when unset.
    #[serde(skip_serializing_if = "Option::is_none")]
    status_text: Option<String>,
    /// Unix timestamp (seconds) when the status file was last written.
    /// `None` when no status is set.
    #[serde(skip_serializing_if = "Option::is_none")]
    status_set_at: Option<i64>,
    /// Full context-window size from the most recent completed turn
    /// (`ctx_usage.context_tokens()` = input + cache-read + cache-creation).
    /// `None` until the first turn finishes. Drives the `ctx·Nk` card badge.
    #[serde(skip_serializing_if = "Option::is_none")]
    ctx_tokens: Option<u64>,
    /// Effective context-window budget for the current model. Same
    /// derivation as `StateSnapshot::context_window_tokens`.
    context_window_tokens: u64,
    /// True while the harness is parked after a rate-limit response.
    rate_limited: bool,
    /// Navigation links for the dashboard card's icon strip. This is
    /// the authoritative source — includes the screen link (GUI agents)
    /// which hive-c0re's disk-based fallback cannot determine.
    links: Vec<AgentLink>,
}

/// Read the agent's own free-text status and the timestamp when it was
/// set, directly from the `hyperhive-status` file in the state dir.
/// Mirrors `hive_c0re::container_view::read_agent_status` but runs
/// inside the agent container using its own state dir.
fn read_own_status() -> (Option<String>, Option<i64>) {
    let path = crate::paths::state_dir().join("hyperhive-status");
    let meta = std::fs::metadata(&path).ok();
    let text = std::fs::read_to_string(&path)
        .ok()
        .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)
    }
}

/// Build the navigation link list for the agent page header. URLs
/// are paths (relative) for `Container`/`Forge` targets and absolute
/// for `External`; the frontend resolves each against its `kind`
/// against the right base so the backend never has to guess the
/// operator's browser host. See
/// [`docs/web-ui/dashboard.md::Container row`](../../../docs/web-ui/dashboard.md) for
/// the resolver + how `deployed:<sha>` ships alongside.
fn agent_links(label: &str, gui_enabled: bool) -> Vec<AgentLink> {
    let mut links = Vec::new();

    links.push(AgentLink {
        url: "stats.html".to_owned(),
        icon: "📊".to_owned(),
        label: "stats".to_owned(),
        kind: AgentLinkKind::Container,
    });

    if gui_enabled {
        links.push(AgentLink {
            url: "screen.html".to_owned(),
            icon: "🖥".to_owned(),
            label: "screen".to_owned(),
            kind: AgentLinkKind::Container,
        });
    }

    if crate::paths::state_dir().join("forge-token").is_file() {
        links.push(AgentLink {
            url: format!("/{label}"),
            icon: "⬡".to_owned(),
            label: "forge".to_owned(),
            kind: AgentLinkKind::Forge,
        });
        links.push(AgentLink {
            url: format!("/agent-configs/{label}"),
            icon: "↳".to_owned(),
            label: "config".to_owned(),
            kind: AgentLinkKind::Forge,
        });
    }

    // Agent-declared extras (`hyperhive.dashboardLinks` → the
    // `hive-dashboard-links` NixOS oneshot writes them to
    // `{state_dir}/hyperhive-dashboard-links.json`). Shape on disk
    // is `{label, icon, url}` with absolute URLs — those become
    // `kind = External` links, passed through verbatim.
    let extras_path = crate::paths::state_dir().join("hyperhive-dashboard-links.json");
    if let Ok(text) = std::fs::read_to_string(&extras_path)
        && !text.trim().is_empty()
        && let Ok(extras) = serde_json::from_str::<Vec<ExtraLink>>(&text)
    {
        for e in extras {
            links.push(AgentLink {
                url: e.url,
                icon: e.icon,
                label: e.label,
                kind: AgentLinkKind::External,
            });
        }
    }

    links
}

/// On-disk shape of `hyperhive-dashboard-links.json` (the
/// `hive-dashboard-links` NixOS oneshot's output). Mapped to
/// `AgentLink { kind: External }` inside `agent_links`.
#[derive(serde::Deserialize)]
struct ExtraLink {
    label: String,
    #[serde(default)]
    icon: String,
    url: String,
}

/// Best-effort: pull the last 30 messages addressed to us via the
/// per-agent / manager socket. Empty list on any transport / decode
/// failure — the inbox section is decorative, not authoritative.
async fn recent_inbox(socket: &std::path::Path) -> Vec<hive_sh4re::inbox::InboxRow> {
    const LIMIT: u64 = 30;
    // Deadline-bounded (via `broker_request`): `/api/state` must render even
    // when hive-c0re is busy — an empty inbox section beats a hung snapshot.
    match super::broker_request(
        socket,
        &hive_core_agent_sock::Request::Recent { limit: LIMIT },
    )
    .await
    {
        Ok(hive_core_agent_sock::Response::Recent { rows }) => rows,
        _ => Vec::new(),
    }
}

/// Read `HIVE_AVAILABLE_MODELS` (comma-separated short names injected by
/// `services.hyperhive.availableModels`) and return the parsed list.
/// Falls back to `["haiku", "sonnet", "opus"]` when the env var is absent
/// or resolves to an empty list after trimming.
fn available_models() -> Vec<String> {
    const DEFAULT: &[&str] = &["haiku", "sonnet", "opus"];
    // Absent / empty / all-whitespace env all funnel to the single
    // emptiness check below — no separate up-front guard needed.
    let models: Vec<String> = std::env::var("HIVE_AVAILABLE_MODELS")
        .unwrap_or_default()
        .split(',')
        .map(|s| s.trim().to_string())
        .filter(|s| !s.is_empty())
        .collect();
    if models.is_empty() {
        DEFAULT.iter().map(ToString::to_string).collect()
    } else {
        models
    }
}