/**
 * session-status-bar.ts — Status bar component for the live session TUI.
 *
 * Shows animated spinner, agent type, description, elapsed time,
 * tool use count, and turn count in a single compact line.
 */
import {
  type Component,
  type TUI,
  truncateToWidth,
} from "@mariozechner/pi-tui";
import type { AgentSessionEvent, SessionEventStream } from "../session-events.js";
import type { Theme } from "./agent-widget.js";
import { SPINNER } from "./agent-widget.js";

// ---- Constants ----

/** Tick interval for elapsed time updates (ms). */
const ELAPSED_TICK_MS = 1000;
/** Spinner frame interval (ms). */
const SPINNER_TICK_MS = 200;

// ---- StatusBar Component ----

/**
 * Status bar showing live agent session stats.
 */
export class SessionStatusBar implements Component {
  private spinnerIdx = 0;
  private elapsed = 0;
  private toolCount = 0;
  private turnCount = 0;
  private status: string = "running";
  private startTime: number;
  private timerHandle: ReturnType<typeof setInterval> | null = null;
  private spinnerHandle: ReturnType<typeof setInterval> | null = null;
  private unsubscribe: (() => void) | null = null;
  private closed = false;

  constructor(
    private tui: TUI,events: SessionEventStream,
    private theme: Theme,
    private record: { type: string; description: string; createdAt?: number; startedAt?: number },
  ) {
    this.startTime = record.startedAt ?? record.createdAt ?? Date.now();
    this.startTimers();

    this.unsubscribe = events.subscribe((event: AgentSessionEvent) => {
      if (this.closed) return;
      this.handleEvent(event);
      this.tui.requestRender();
    });
  }

  /**
   * Handle session events to update counters.
   */
  private handleEvent(event: AgentSessionEvent): void {
    switch (event.type) {
      case "tool_start":
        this.toolCount++;
        break;
      case "turn_end":
        this.turnCount++;
        break;
      case "status":
        this.status = event.status;
        break;
      default:
        break;
    }
  }

  /**
   * Start timers for elapsed time and spinner animation.
   */
  private startTimers(): void {
    if (this.timerHandle) clearInterval(this.timerHandle);
    if (this.spinnerHandle) clearInterval(this.spinnerHandle);

    this.timerHandle = setInterval(() => {
      if (this.closed) return;
      this.elapsed = Math.floor((Date.now() - this.startTime) / 1000);
      this.tui.requestRender();
    }, ELAPSED_TICK_MS);

    this.spinnerHandle = setInterval(() => {
      if (this.closed) return;
      this.spinnerIdx = (this.spinnerIdx + 1) % SPINNER.length;
      this.tui.requestRender();
    }, SPINNER_TICK_MS);
  }

  // ---- Component Interface ----

  render(width: number): string[] {
    if (this.closed || width < 20) return [];

    const th = this.theme;
    const spinner = SPINNER[this.spinnerIdx];

    // Status icon
    let statusIcon: string;
    let statusColor: string;
    switch (this.status) {
      case "running":
        statusIcon = spinner;
        statusColor = "accent";
        break;
      case "completed":
        statusIcon = "✓";
        statusColor = "success";
        break;
      case "error":
      case "aborted":
      case "stopped":
        statusIcon = "✕";
        statusColor = "error";
        break;
      default:
        statusIcon = "◌";
        statusColor = "dim";
        break;
    }

    // Agent name + description
    const name = this.record.type;
    const desc = this.record.description ?? "";

    // Stats
    const elapsedStr = this.formatElapsed(this.elapsed);
    const toolStr = `${this.toolCount} tool${this.toolCount === 1 ? "" : "s"}`;
    const turnStr = `${this.turnCount} turn${this.turnCount === 1 ? "" : "s"}`;

    // Build content
    const iconPart = th.fg(statusColor, statusIcon);
    const namePart = th.bold(name);
    const descPart = desc ? ` ${th.fg("muted", "·")} ${th.fg("dim", truncateToWidth(desc, Math.max(10, Math.floor(width * 0.3))))}` : "";
    const statsPart = th.fg("dim", ` ${th.fg("dim", "·")} ${elapsedStr} ${th.fg("dim", "·")} ${toolStr} ${th.fg("dim", "·")} ${turnStr}`);

    const full = `${iconPart} ${namePart}${descPart}${statsPart}`;
    const padded = truncateToWidth(full, width);

    return [padded];
  }

  handleInput(_data: string): void {
    // No input handling needed
  }

  invalidate(): void {
    // No cached state
  }

  dispose(): void {
    this.closed = true;
    if (this.timerHandle) {
      clearInterval(this.timerHandle);
      this.timerHandle = null;
    }
    if (this.spinnerHandle) {
      clearInterval(this.spinnerHandle);
      this.spinnerHandle = null;
    }
    if (this.unsubscribe) {
      this.unsubscribe();
      this.unsubscribe = null;
    }
  }

  // ---- Private ----

  /**
   * Format elapsed seconds into a human-readable duration string.
   */
  private formatElapsed(seconds: number): string {
    if (seconds < 60) return `${seconds}s`;
    const m = Math.floor(seconds / 60);
    const s = seconds % 60;
    return `${m}m ${s}s`;
  }
}