/**
 * pi-tmux-status - Show pi panel status in the tmux status bar
 *
 * Each pi instance writes its state to /tmp/pi-tmux-{pane_id}.txt.
 * A companion shell script (auto-installed to ~/.config/tmux/pi-status.sh)
 * reads these files and renders colored icons in tmux's window-status-format.
 *
 * States:
 *   idle    (grey   ○)            - waiting for user input
 *   working (yellow ●, blinking)  - processing (LLM streaming / tools)
 *   asking  (red    ●)            - waiting for user response (interactive tool / question)
 *
 * Setup (add to ~/.tmux.conf):
 *   set -g status-interval 1
 *   set -g window-status-format         " #I:#W#(~/.config/tmux/pi-status.sh #{window_id}) "
 *   set -g window-status-current-format " #I:#W*#(~/.config/tmux/pi-status.sh #{window_id}) "
 *
 * Requires: tmux 3.2+, running inside tmux ($TMUX_PANE)
 */

import type { ExtensionAPI, ExtensionContext } from "@earendil-works/pi-coding-agent";
import { writeFileSync, unlinkSync, existsSync, mkdirSync } from "node:fs";
import { dirname } from "node:path";
import { homedir } from "node:os";
import { spawn } from "node:child_process";

const STATUS_DIR = "/tmp";
const PREFIX = "pi-tmux-";
const SCRIPT_PATH = `${homedir()}/.config/tmux/pi-status.sh`;

// Tools that block on user input - while these run, pi is "asking"
const INTERACTIVE_TOOLS = new Set(["ask_user_question"]);

let currentState: "idle" | "working" | "asking" = "idle";
let interactiveCount = 0;

// ── Status file helpers ─────────────────────────────────────────

function statusFile(): string | null {
  const pane = process.env.TMUX_PANE;
  return pane ? `${STATUS_DIR}/${PREFIX}${pane}.txt` : null;
}

function flush(): void {
  const f = statusFile();
  if (!f) return;
  try { writeFileSync(f, `${currentState} ${process.pid}\n`); } catch { /* ok */ }
}

function removeStatus(): void {
  const f = statusFile();
  if (!f) return;
  try { if (existsSync(f)) unlinkSync(f); } catch { /* ok */ }
}

// ── tmux refresh (fire-and-forget) ──────────────────────────────

function pokeTmux(): void {
  try {
    spawn("tmux", ["refresh-client", "-S"], { stdio: "ignore", detached: true }).unref();
  } catch { /* ok */ }
}

// ── Auto-install the companion shell script ─────────────────────

const SCRIPT_CONTENT = `#!/usr/bin/env bash
# pi-status.sh - auto-generated by pi-tmux-status extension
# Renders colored icons for each pi instance in the current tmux window.

set -euo pipefail

WINDOW_ID="\${1:-}"
[[ -n "$WINDOW_ID" ]] || exit 0

DIR="/tmp"
PFX="pi-tmux-"

read_state() {
  local f="$1"
  [[ -f "$f" ]] || { echo "none"; return; }
  local state pid
  read -r state pid 2>/dev/null < "$f" || { echo "none"; return; }
  if [[ -n "$pid" && "$pid" != "0" ]] && ! kill -0 "$pid" 2>/dev/null; then
    rm -f "$f" 2>/dev/null || true
    echo "none"
    return
  fi
  echo "\${state:-idle}"
}

panes=$(tmux list-panes -t "$WINDOW_ID" -F "#{pane_id} #{pane_index}" 2>/dev/null |
        sort -k2 -n | awk '{print $1}' 2>/dev/null) || panes=""

[[ -z "$panes" ]] && exit 0

icons=()
for pane in $panes; do
  f="\${DIR}/\${PFX}\${pane}.txt"
  s=$(read_state "$f")
  case "$s" in
    working) icons+=("#[fg=colour220,blink]\u25cf#[default]") ;;
    asking)  icons+=("#[fg=colour196]\u25cf#[default]") ;;
    idle)    icons+=("#[fg=colour245]\u25cb#[default]") ;;
    *)       ;;
  esac
done

[[ \${#icons[@]} -eq 0 ]] && exit 0

printf '[%s]' "$(IFS=' '; echo "\${icons[*]}")"
`;

function ensureScript(): void {
  try {
    mkdirSync(dirname(SCRIPT_PATH), { recursive: true });
    writeFileSync(SCRIPT_PATH, SCRIPT_CONTENT, { mode: 0o755 });
  } catch { /* ok */ }
}

// ── Asking detection ────────────────────────────────────────────

function looksLikeQuestion(text: string): boolean {
  if (!text) return false;
  return /(^|\n)\s*[^\n]*\?\s*$/m.test(text.trim());
}

function detectAsking(ctx: ExtensionContext): boolean {
  try {
    const entries = (ctx as any).sessionManager?.getBranch?.();
    if (!entries?.length) return false;
    for (let i = entries.length - 1; i >= 0; i--) {
      const e = entries[i];
      if (e?.type === "message" && e?.message?.role === "assistant") {
        const c = e.message.content;
        if (Array.isArray(c)) {
          const text = c.filter((b: any) => b.type === "text").map((b: any) => b.text).join("\n");
          return looksLikeQuestion(text);
        }
        return false;
      }
    }
  } catch { /* ok */ }
  return false;
}

// ── Extension ───────────────────────────────────────────────────

export default function (pi: ExtensionAPI) {
  if (!process.env.TMUX_PANE) return;

  ensureScript();

  function set(s: typeof currentState) {
    if (currentState === s) return;
    currentState = s;
    flush();
    pokeTmux();
  }

  pi.on("session_start", async () => {
    currentState = "idle";
    interactiveCount = 0;
    flush();
    pokeTmux();
  });

  pi.on("agent_start", () => set("working"));

  pi.on("tool_call", async (event) => {
    if (INTERACTIVE_TOOLS.has(event.toolName)) {
      interactiveCount++;
      set("asking");
    }
  });

  pi.on("tool_execution_end", async (event) => {
    if (INTERACTIVE_TOOLS.has(event.toolName)) {
      interactiveCount = Math.max(0, interactiveCount - 1);
      if (interactiveCount === 0 && currentState === "asking") {
        set("working");
      }
    }
  });

  pi.on("agent_end", async (_ev, ctx) => {
    interactiveCount = 0;
    set(detectAsking(ctx) ? "asking" : "idle");
  });

  pi.on("session_shutdown", () => { removeStatus(); pokeTmux(); });
  process.on("exit", () => removeStatus());
}