/**
 * KHAELOR
 * File: src/tui/components/status-line.ts
 * Description: The single agent status line — real states, real elapsed timers, the 2 Hz pulse (TUI_DESIGN §5).
 *
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 */

import { truncateAnsi } from "../renderer/ansi.js";
import type { StyleRole, Theme } from "../theme.js";

export type AgentStateKind =
  | "idle"
  | "thinking"
  | "reading"
  | "searching"
  | "editing"
  | "running"
  | "waiting"
  | "verifying"
  | "stopping";

export interface AgentStatus {
  kind: AgentStateKind;
  /** What, concretely: a path, a command, a query. Never fabricated. */
  detail?: string;
  /** Real timestamp when this state began (elapsed timer source). */
  startedAt: number;
  /** Real extracted progress like "41/148" — only when a parser produced it. */
  progress?: string;
}

const LABELS: Record<Exclude<AgentStateKind, "idle" | "stopping">, string> = {
  thinking: "Thinking",
  reading: "Reading",
  searching: "Searching",
  editing: "Editing",
  running: "Running",
  waiting: "Waiting for permission",
  verifying: "Verifying",
};

/** One saturated color per agent state — the word still carries the meaning. */
const STATE_COLOR: Record<Exclude<AgentStateKind, "idle" | "stopping">, StyleRole> = {
  thinking: "violet",
  reading: "cyan",
  searching: "teal",
  editing: "warning",
  running: "success",
  waiting: "orange",
  verifying: "magenta",
};

/**
 * Render the one compact dynamic status line, or null when idle (the line
 * collapses and the composer moves up a row). Every element is real data:
 * elapsed comes from `now - startedAt`; `progress` appears only when actually
 * extracted. `●` pulses between two shades at ~2 Hz — the only animation in
 * the product; in monochrome the glyph itself carries the state.
 */
export function renderStatusLine(
  status: AgentStatus,
  now: number,
  theme: Theme,
  width: number,
): string | null {
  if (status.kind === "idle") return null;
  if (status.kind === "stopping") {
    return truncateAnsi(` ${theme.paint("warning", "◌")} Stopping…`, width);
  }

  const pulseOn = Math.floor(now / 250) % 2 === 0;
  const color = STATE_COLOR[status.kind];
  const dot = theme.paint(pulseOn ? color : "accentDim", "●");

  const parts: string[] = [theme.paint(color, LABELS[status.kind])];
  if (status.detail !== undefined && status.detail !== "") parts.push(status.detail);
  if (status.progress !== undefined && status.progress !== "") {
    parts.push(status.progress);
  } else {
    const elapsed = Math.max(0, now - status.startedAt) / 1000;
    if (elapsed >= 0.1) parts.push(`${elapsed.toFixed(1)}s`);
  }

  const body = parts.join(theme.paint("dim", " · "));
  return truncateAnsi(` ${dot} ${body}`, width);
}