/**
 * Pomodoro Timer Extension
 *
 * Puts a Pomodoro timer in the pi status bar.
 *
 * Phases:
 *   🍅 Work      — 25 minutes
 *   ☕ Break     —  5 minutes  (short break)
 *   🛋️  Long Break — 15 minutes (after every 4 pomodoros)
 *
 * Commands:
 *   /pomodoro start   — start (or resume) the timer
 *   /pomodoro pause   — pause the timer
 *   /pomodoro stop    — stop and reset the current phase
 *   /pomodoro skip    — skip to the next phase
 *   /pomodoro reset   — stop and reset everything, including the count
 *   /pomodoro status  — print current timer state
 *
 * Shortcut:
 *   Ctrl+Shift+T — toggle start / pause
 */

import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import { Key } from "@earendil-works/pi-tui";

// ─── Durations ───────────────────────────────────────────────────────────────

const WORK_SECS = 25 * 60;
const SHORT_BREAK_SECS = 5 * 60;
const LONG_BREAK_SECS = 15 * 60;
const POMODOROS_PER_LONG_BREAK = 4;

// ─── Types ───────────────────────────────────────────────────────────────────

type Phase = "work" | "shortBreak" | "longBreak";

interface UI {
  theme: {
    fg(color: string, text: string): string;
    bold?(text: string): string;
  };
  setStatus(id: string, text: string | undefined): void;
  notify(message: string, level: "info" | "error" | "warning" | "success"): void;
}

// ─── Helpers ─────────────────────────────────────────────────────────────────

function formatTime(seconds: number): string {
  const m = Math.floor(seconds / 60)
    .toString()
    .padStart(2, "0");
  const s = (seconds % 60).toString().padStart(2, "0");
  return `${m}:${s}`;
}

function phaseEmoji(phase: Phase): string {
  switch (phase) {
    case "work":
      return "🍅";
    case "shortBreak":
      return "☕";
    case "longBreak":
      return "🛋️";
  }
}

function phaseLabel(phase: Phase): string {
  switch (phase) {
    case "work":
      return "Work";
    case "shortBreak":
      return "Break";
    case "longBreak":
      return "Long Break";
  }
}

function phaseDuration(phase: Phase): number {
  switch (phase) {
    case "work":
      return WORK_SECS;
    case "shortBreak":
      return SHORT_BREAK_SECS;
    case "longBreak":
      return LONG_BREAK_SECS;
  }
}

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

export default function (pi: ExtensionAPI) {
  // Mutable state – captured from session_start / command handlers
  let ui: UI | null = null;
  let interval: ReturnType<typeof setInterval> | null = null;

  let running = false;
  let phase: Phase = "work";
  let secondsLeft = WORK_SECS;
  let pomodoroCount = 0; // completed work sessions this session

  // ─── Status bar rendering ──────────────────────────────────────────────────

  function renderStatus(): void {
    if (!ui) return;
    const theme = ui.theme;

    // Idle: show nothing
    if (!running && secondsLeft === phaseDuration(phase) && pomodoroCount === 0) {
      ui.setStatus("pomodoro", undefined);
      return;
    }

    const emoji = phaseEmoji(phase);
    const time = formatTime(secondsLeft);
    const count = pomodoroCount > 0 ? ` ×${pomodoroCount}` : "";
    const pause = !running ? " ⏸" : "";

    // Work phases get accent color; breaks get success (greenish)
    const color = phase === "work" ? "accent" : "success";
    ui.setStatus("pomodoro", theme.fg(color, `${emoji} ${time}${count}${pause}`));
  }

  // ─── Timer logic ──────────────────────────────────────────────────────────

  function startInterval(): void {
    if (interval) return;
    interval = setInterval(() => {
      if (!running) return;
      secondsLeft--;
      if (secondsLeft <= 0) {
        advancePhase();
      } else {
        renderStatus();
      }
    }, 1000);
  }

  function clearTimerInterval(): void {
    if (interval) {
      clearInterval(interval);
      interval = null;
    }
  }

  function advancePhase(): void {
    if (phase === "work") {
      pomodoroCount++;
      const isLongBreak = pomodoroCount % POMODOROS_PER_LONG_BREAK === 0;
      phase = isLongBreak ? "longBreak" : "shortBreak";
      secondsLeft = phaseDuration(phase);
      ui?.notify(
        `🍅 Pomodoro #${pomodoroCount} done! ${isLongBreak ? "Take a long break 🛋️" : "Take a short break ☕"}`,
        "info",
      );
    } else {
      phase = "work";
      secondsLeft = WORK_SECS;
      ui?.notify("⏰ Break over — time to focus! 🍅", "info");
    }
    renderStatus();
  }

  function start(): void {
    running = true;
    startInterval();
    renderStatus();
  }

  function pause(): void {
    running = false;
    renderStatus();
  }

  function stop(): void {
    running = false;
    clearTimerInterval();
    secondsLeft = phaseDuration(phase);
    renderStatus();
  }

  function reset(): void {
    running = false;
    clearTimerInterval();
    phase = "work";
    secondsLeft = WORK_SECS;
    pomodoroCount = 0;
    renderStatus();
  }

  function skip(): void {
    advancePhase();
  }

  // ─── Events ───────────────────────────────────────────────────────────────

  pi.on("session_start", async (_event, ctx) => {
    ui = ctx.ui as unknown as UI;
    renderStatus();
  });

  pi.on("session_shutdown", async () => {
    clearTimerInterval();
    running = false;
    ui = null;
  });

  // ─── /pomodoro command ────────────────────────────────────────────────────

  pi.registerCommand("pomodoro", {
    description:
      "Pomodoro timer — sub-commands: start, pause, stop, skip, reset, status",
    handler: async (args, ctx) => {
      // Refresh ui reference so the timer can fire notifications even if the
      // session_start capture happened on a previous session.
      ui = ctx.ui as unknown as UI;

      const sub = args?.trim().toLowerCase() || "start";

      switch (sub) {
        case "start":
        case "resume":
          if (running) {
            ctx.ui.notify("Timer is already running.", "info");
          } else {
            start();
            ctx.ui.notify(
              `▶ ${phaseEmoji(phase)} ${phaseLabel(phase)} started — ${formatTime(secondsLeft)} remaining`,
              "info",
            );
          }
          break;

        case "pause":
          if (!running) {
            ctx.ui.notify("Timer is not running.", "info");
          } else {
            pause();
            ctx.ui.notify(`⏸ Paused at ${formatTime(secondsLeft)}`, "info");
          }
          break;

        case "stop":
          stop();
          ctx.ui.notify("⏹ Timer stopped.", "info");
          break;

        case "skip":
          skip();
          ctx.ui.notify(
            `⏭ Skipped to ${phaseEmoji(phase)} ${phaseLabel(phase)} — ${formatTime(secondsLeft)} remaining`,
            "info",
          );
          break;

        case "reset":
          reset();
          ctx.ui.notify("🔄 Timer reset.", "info");
          break;

        case "status": {
          const state = running
            ? `▶ ${phaseEmoji(phase)} ${phaseLabel(phase)} — ${formatTime(secondsLeft)} left`
            : secondsLeft < phaseDuration(phase)
              ? `⏸ ${phaseEmoji(phase)} ${phaseLabel(phase)} — ${formatTime(secondsLeft)} left (paused)`
              : `⏹ Stopped (${phaseLabel(phase)})`;
          const summary =
            pomodoroCount > 0
              ? `Completed this session: ${pomodoroCount} 🍅`
              : "No pomodoros completed yet.";
          ctx.ui.notify(`${state}\n${summary}`, "info");
          break;
        }

        default:
          ctx.ui.notify(
            `Unknown sub-command "${sub}". Try: start, pause, stop, skip, reset, status`,
            "error",
          );
      }
    },
  });

  // ─── Ctrl+Shift+T shortcut — toggle start / pause ─────────────────────────

  pi.registerShortcut(Key.ctrlShift("t"), {
    description: "Toggle Pomodoro timer (start / pause)",
    handler: async (ctx) => {
      ui = ctx.ui as unknown as UI;
      if (running) {
        pause();
        ctx.ui.notify(`⏸ Pomodoro paused at ${formatTime(secondsLeft)}`, "info");
      } else {
        start();
        ctx.ui.notify(
          `▶ ${phaseEmoji(phase)} ${phaseLabel(phase)} running — ${formatTime(secondsLeft)} remaining`,
          "info",
        );
      }
    },
  });
}