// <AgentTermPreview> — the MVP mara's own ruling asked for: not a separate
// page, a small preview in an opened agent card on `AgentsPage`, with
// an `AgentInputForm` under an agent's terminal (a subagent's has none: it
// takes no input of its own). Consumes swarm-controller's
// `GET /api/agents/{name}/term/stream`, or for a subagent
// `GET /api/agents/{name}/subagents/{subagent}/term/stream`, via
// `useSwarmTermStream`, rendering through the same `@hive/shared` `Row`
// component the per-hive local terminal uses — "share components between hive and swarm level
// term as much as possible" (mara).
//
// **Floating header badges** — turn state / model / ctx / cost parity
// with the per-agent page's own `StatusChips` — mara: "dont make it a
// header though - make it floating elements on top of the terminal", so
// this is a small `Badge` cluster pinned to the terminal box's own
// corner (`.terminal-wrap`'s `position: relative`, same anchor
// `@hive/shared/terminal.css`'s `.tail-pill` already uses), not a
// separate layout row. Read-only, no click targets: pause/resume already
// has its own control surface (`WantedMenu` on `AgentsPage`), so nothing
// here needs to be interactive. Sourced from `useSwarmAgentStateStream`,
// not from `AgentRow` — the roster fetch `AgentsPage` already did has no
// notion of turn_state/model/ctx/cost, only `wanted`/`snapshot.running`.
// Only the full-tab mount (`fullHeight`) shows the state badges: the small
// preview in an opened card stays free of them (mara: "the preview is small
// and should not be encroached further with badges on top, but for the full
// screen term i want it like that"), and the card's overview lists the
// same state in a row of its own (`AgentStateRow`).

// **Expand-to-fullscreen trigger** — opens/navigates to
// `/agents/:name/terminal` (`AgentTerminalPage`) via `useDynamicTabs`,
// same header-tab mechanism `Shell`'s own nav row now shares. Lives here
// (not on `AgentsPage`) so both the embedded preview and the future full
// page mount the identical trigger without either needing to know where
// the other one is. Suppressed via `fullHeight` — the full-page mount
// already IS the destination, so it has nothing further to expand to.
import { useLayoutEffect, useRef, useState } from "preact/hooks";
import type { ComponentChildren } from "preact";
import { Badge, type BadgeTone } from "@hive/shared/badge.js";
import { ExpandIcon } from "@hive/shared/icons.js";
import { Row } from "@hive/shared/term-row.js";
import { useDynamicTabs } from "../../shell/useDynamicTabs.js";
import {
  useSwarmTermStream,
  type ConnectionState,
} from "./useSwarmTermStream.js";
import { useSwarmAgentStateStream } from "./useSwarmAgentStateStream.js";
import { termPaths } from "./term-paths.js";
import { StateBadges, tokenTotal } from "../state/StateBadges.js";
import { AgentInputForm } from "./AgentInputForm.js";
import { CancelTurnBadge } from "./CancelTurnBadge.js";
import "./AgentTermPreview.css";

const NEAR_BOTTOM_PX = 48;

const CONNECTION_LABEL: Record<ConnectionState, string> = {
  connecting: "connecting…",
  open: "live",
  reconnecting: "reconnecting…",
  closed: "disconnected",
};

const CONNECTION_TONE: Record<ConnectionState, BadgeTone> = {
  connecting: "neutral",
  open: "positive",
  reconnecting: "warning",
  closed: "negative",
};

export function AgentTermPreview({
  agentName,
  subagent,
  fullHeight = false,
  leading,
  trailing,
}: {
  agentName: string;
  // Set: this is one of `agentName`'s subagents, output only like the
  // agent's own.
  subagent?: string;
  // The full-tab mount: fills the tab, has no expand trigger, and shows the
  // agent's state badges beside the connection one.
  fullHeight?: boolean;
  // A badge ahead of the connection badge, for the full-tab mount's
  // link back to the agent's details.
  leading?: ComponentChildren;
  // Icon-only badges in the top right corner, for the full-tab mount's own
  // controls (a group pane's maximize and close).
  trailing?: ComponentChildren;
}) {
  const paths = termPaths(agentName, subagent);
  const { rows, connection, reconnect } = useSwarmTermStream(paths.stream);
  // The small preview has no state badges, so it does not follow the state
  // stream at all.
  const { header, reconnect: reconnectState } = useSwarmAgentStateStream(
    fullHeight ? paths.state : null,
  );
  const { open: openTab } = useDynamicTabs();
  const logRef = useRef<HTMLDivElement>(null);
  const [stickToBottom, setStickToBottom] = useState(true);

  const ctx = header ? tokenTotal(header.ctx_usage) : null;
  const cost = header ? tokenTotal(header.cost_usage) : null;

  function handleScroll() {
    const el = logRef.current;
    if (!el) return;
    setStickToBottom(
      el.scrollHeight - el.scrollTop - el.clientHeight <= NEAR_BOTTOM_PX,
    );
  }

  // Runs after Preact has committed new rows, so `scrollHeight` is
  // already current — same ordering `@hive/agent`'s `LiveStream` uses.
  useLayoutEffect(() => {
    const el = logRef.current;
    if (el && stickToBottom) el.scrollTop = el.scrollHeight - el.clientHeight;
  }, [rows, stickToBottom]);

  return (
    <div
      class={
        "ui-agent-term-preview" +
        (fullHeight ? " ui-agent-term-preview-full" : "")
      }
    >
      <div class="terminal-wrap ui-agent-term-preview-wrap">
        {/* One floating row over the terminal's top edge: the state
            badges (connection first) on the left, the expand trigger on
            the right. The full-tab mount is already the destination, so
            it has no expand trigger. */}
        <div class="ui-agent-term-preview-controls">
          <div class="ui-agent-term-preview-header-badges">
            {leading}
            <Badge
              tone={CONNECTION_TONE[connection]}
              value={CONNECTION_LABEL[connection]}
            />
            {connection === "closed" && (
              <Badge
                variant="quiet"
                value="reconnect"
                title={`open ${paths.label}'s terminal stream again`}
                onClick={() => {
                  reconnect();
                  reconnectState();
                }}
              />
            )}
            {header && (
              <StateBadges
                header={header}
                ctx={ctx}
                cost={cost}
                agent={subagent === undefined ? agentName : undefined}
              />
            )}
            {header && subagent === undefined && (
              <CancelTurnBadge
                agentName={agentName}
                turnState={header.turn_state}
              />
            )}
          </div>
          {!fullHeight && (
            <Badge
              icon={<ExpandIcon />}
              value="expand"
              title={`open ${paths.label}'s terminal in its own tab`}
              onClick={() => openTab({ href: paths.page, label: paths.label })}
            />
          )}
          {trailing !== undefined && (
            <div class="ui-agent-term-preview-trailing">{trailing}</div>
          )}
        </div>
        <div class="live terminal" ref={logRef} onScroll={handleScroll}>
          {rows.length === 0 ? (
            <div class="row note">
              {/* Explicit `.row-content` wrapper, not a bare text child —
                  `.live .row`'s CSS grid (terminal.css) has a narrow
                  first column reserved for a row icon; a row's lone
                  child with no explicit `grid-column` auto-places into
                  that column instead of the content one, wrapping the
                  text one or two characters per line — mara reported
                  exactly this on the live "connecting…" placeholder.
                  `Row.tsx`'s own icon-less flat row already documents
                  and avoids this same trap. */}
              <span class="row-content">
                {connection === "open"
                  ? "(connected — waiting for events)"
                  : CONNECTION_LABEL[connection]}
              </span>
            </div>
          ) : (
            rows.map((row) => <Row key={row.key} row={row} />)
          )}
        </div>
      </div>
      {subagent === undefined && <AgentInputForm agentName={agentName} />}
    </div>
  );
}