/**
 * progress-tracker.ts
 *
 * Extension: Progress Tracker
 * Triggers: on_session_end
 *
 * Tracks weekly activity across skills and sessions.
 * Surfaces burnout prevention nudges and weekly summaries.
 */

import type { ExtensionAPI } from "@earendil-works/pi-coding-agent";
import * as fs from "fs";
import * as path from "path";
import * as os from "os";
import { getWorkspaceState } from "../workspace-detector";
import {
  type TuiTheme,
  badge,
  kv,
  miniBar,
  panelBlank,
  panelBottom,
  panelRow,
  panelTop,
  sectionDivider,
  skillBar,
  wordWrap,
} from "./lib/tui";

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

export interface SessionRecord {
  date: string; // ISO date string
  durationMinutes: number;
  skillsUsed: string[];
  topicsWorked: string[];
}

export interface WeeklyStats {
  totalMinutes: number;
  sessionCount: number;
  skillBreakdown: Record<string, number>;
  longestSession: number;
  streak: number; // days in a row with activity
}

// ─── Storage ───────────────────────────────────────────────────────────────

const TRACKER_DIR = path.join(os.homedir(), ".pisces");
const SESSIONS_FILE = path.join(TRACKER_DIR, "sessions.json");

function ensureTrackerDir(): void {
  if (!fs.existsSync(TRACKER_DIR)) {
    fs.mkdirSync(TRACKER_DIR, { recursive: true });
  }
}

function loadSessions(): SessionRecord[] {
  try {
    if (!fs.existsSync(SESSIONS_FILE)) return [];
    const raw = fs.readFileSync(SESSIONS_FILE, "utf-8");
    return JSON.parse(raw) as SessionRecord[];
  } catch {
    return [];
  }
}

function saveSessions(sessions: SessionRecord[]): void {
  try {
    ensureTrackerDir();
    const cutoff = new Date();
    cutoff.setDate(cutoff.getDate() - 90);
    const recent = sessions.filter((s) => new Date(s.date) > cutoff);
    fs.writeFileSync(SESSIONS_FILE, JSON.stringify(recent, null, 2));
  } catch {
    // Fail silently — tracker is a nice-to-have, not critical
  }
}

// ─── Stats ─────────────────────────────────────────────────────────────────

function getWeeklyStats(sessions: SessionRecord[]): WeeklyStats {
  const oneWeekAgo = new Date();
  oneWeekAgo.setDate(oneWeekAgo.getDate() - 7);

  const weekSessions = sessions.filter(
    (s) => new Date(s.date) > oneWeekAgo
  );

  const skillBreakdown: Record<string, number> = {};
  let totalMinutes = 0;
  let longestSession = 0;

  for (const session of weekSessions) {
    totalMinutes += session.durationMinutes;
    longestSession = Math.max(longestSession, session.durationMinutes);

    for (const skill of session.skillsUsed) {
      skillBreakdown[skill] = (skillBreakdown[skill] ?? 0) + 1;
    }
  }

  // Calculate streak
  let streak = 0;
  const sessionDays = new Set(sessions.map((s) => new Date(s.date).toDateString()));
  const checkDate = new Date();

  while (sessionDays.has(checkDate.toDateString())) {
    streak++;
    checkDate.setDate(checkDate.getDate() - 1);
  }

  return {
    totalMinutes,
    sessionCount: weekSessions.length,
    skillBreakdown,
    longestSession,
    streak,
  };
}

// ─── Nudges ─────────────────────────────────────────────────────────────────

export function getBurnoutNudge(
  sessionDurationMinutes: number,
  stats: WeeklyStats
): string | null {
  if (sessionDurationMinutes >= 180) {
    return "🐠 You've been coding for 3+ hours. Seriously — take a 15-minute break. Your brain consolidates learning during rest, not during grinding.";
  }
  if (stats.totalMinutes > 40 * 60) {
    return "📊 You've put in 40+ hours of study this week. That's impressive, but rest is part of learning. Consistent rest is part of the process.";
  }
  if (stats.streak >= 7) {
    return `🔥 ${stats.streak}-day streak! Consistent daily practice beats marathon sessions. Keep this up.`;
  }
  return null;
}

// ─── Weekly Summary (plain-text fallback) ──────────────────────────────────

export function buildWeeklySummary(stats: WeeklyStats): string {
  if (stats.sessionCount === 0) {
    return "📅 No activity recorded this week. When you're ready to start, just ask!";
  }

  const hours = Math.floor(stats.totalMinutes / 60);
  const minutes = stats.totalMinutes % 60;
  const timeStr = hours > 0 ? `${hours}h ${minutes}m` : `${minutes}m`;

  const topSkills = Object.entries(stats.skillBreakdown)
    .sort(([, a], [, b]) => b - a)
    .slice(0, 3)
    .map(([skill, count]) => `  - /${skill}: ${count} session${count > 1 ? "s" : ""}`)
    .join("\n");

  return [
    `📊 This Week's Summary`,
    ``,
    `⏱  Total study time: ${timeStr}`,
    `📅 Sessions: ${stats.sessionCount}`,
    `🔥 Current streak: ${stats.streak} day${stats.streak !== 1 ? "s" : ""}`,
    topSkills ? `\n🛠  Most used skills:\n${topSkills}` : "",
    ``,
    stats.totalMinutes < 5 * 60
      ? `💡 Tip: Even 30 minutes a day compounds significantly over a semester.`
      : `✅ Solid week. Keep the consistency going.`,
  ]
    .filter(Boolean)
    .join("\n");
}

// ─── TUI overlay constants ─────────────────────────────────────────────────

const NUDGE_INNER_W = 52;
const PROGRESS_INNER_W = 56;
const DISMISS_HINT = "─── any key to dismiss ───";

// ─── Nudge panel component (burnout / break reminders) ─────────────────────

function makeNudgeComponent(
  rawText: string,
  t: TuiTheme,
  done: () => void,
) {
  const w = NUDGE_INNER_W;
  const rows: Array<{ text: string; visualW: number }> = [];

  for (const raw of rawText.split("\n")) {
    if (raw === "") {
      rows.push({ text: "", visualW: 0 });
    } else {
      const wrapped = raw.length <= w ? [raw] : wordWrap(raw, w);
      for (const line of wrapped) {
        rows.push({ text: line, visualW: line.length });
      }
    }
  }

  return {
    render(): string[] {
      const out: string[] = [];
      out.push(panelTop(w, "accent", t));
      out.push(panelBlank(w, "accent", t));
      for (const row of rows) {
        if (row.visualW === 0) {
          out.push(panelBlank(w, "accent", t));
        } else {
          out.push(panelRow(row.text, row.visualW, w, "accent", t));
        }
      }
      out.push(panelBlank(w, "accent", t));
      out.push(panelBottom(w, DISMISS_HINT, "accent", t));
      return out;
    },
    invalidate() {},
    handleInput() { done(); },
  };
}

// ─── Progress dashboard component ──────────────────────────────────────────

const STAT_LABEL_W = 13;
const SKILL_NAME_W = 12;
const SKILL_BAR_W = 10;

function buildProgressRows(
  stats: WeeklyStats,
  innerW: number,
  t: TuiTheme,
): Array<{ text: string; visualW: number }> {
  const rows: Array<{ text: string; visualW: number }> = [];

  // Header badge
  const badgeText = badge("THIS WEEK", "accent", t);
  rows.push({ text: badgeText, visualW: "[ THIS WEEK ]".length });
  rows.push({ text: "", visualW: 0 });

  if (stats.sessionCount === 0) {
    const msg = "No activity recorded this week. Ready when you are!";
    for (const line of wordWrap(msg, innerW)) {
      rows.push({ text: t.fg("muted", line), visualW: line.length });
    }
    rows.push({ text: "", visualW: 0 });
    rows.push({
      text: t.fg("dim", "Start a session and run /progress to see your stats."),
      visualW: "Start a session and run /progress to see your stats.".length,
    });
    return rows;
  }

  // Stat rows
  const hours = Math.floor(stats.totalMinutes / 60);
  const minutes = stats.totalMinutes % 60;
  const timeStr = hours > 0 ? `${hours}h ${minutes}m` : `${minutes}m`;
  rows.push(kv("Study time", timeStr, STAT_LABEL_W, "accent", t));
  rows.push(kv("Sessions", String(stats.sessionCount), STAT_LABEL_W, "accent", t));

  // Streak with mini bar (7-day window)
  const streakDays = Math.min(stats.streak, 7);
  const streakBar = miniBar(streakDays, 7, "accent", t);
  const streakLabel = `${stats.streak} day${stats.streak !== 1 ? "s" : ""}`;
  const streakVisualW = STAT_LABEL_W + 2 + streakLabel.length + 2 + 7;
  rows.push({
    text:
      t.fg("muted", "Streak".padEnd(STAT_LABEL_W)) +
      "  " +
      t.fg("accent", streakLabel) +
      "  " +
      streakBar,
    visualW: streakVisualW,
  });

  // Top skills section
  const topSkills = Object.entries(stats.skillBreakdown)
    .sort(([, a], [, b]) => b - a)
    .slice(0, 3);

  if (topSkills.length > 0) {
    rows.push({ text: "", visualW: 0 });
    rows.push(sectionDivider("top skills", innerW, t));
    rows.push({ text: "", visualW: 0 });
    const maxCount = topSkills[0][1];
    for (const [name, count] of topSkills) {
      rows.push(skillBar(name, count, maxCount, SKILL_NAME_W, SKILL_BAR_W, "accent", t));
    }
  }

  rows.push({ text: "", visualW: 0 });

  // Tip / encouragement line
  const tip =
    stats.totalMinutes < 5 * 60
      ? "💡 Tip: Even 30 minutes a day compounds significantly over a semester."
      : "✅ Solid week. Keep the consistency going.";
  for (const line of wordWrap(tip, innerW)) {
    rows.push({ text: t.fg("muted", line), visualW: line.length });
  }

  return rows;
}

function makeProgressComponent(
  stats: WeeklyStats,
  t: TuiTheme,
  done: () => void,
) {
  const w = PROGRESS_INNER_W;
  const rows = buildProgressRows(stats, w, t);

  return {
    render(): string[] {
      const out: string[] = [];
      out.push(panelTop(w, "accent", t));
      out.push(panelBlank(w, "accent", t));
      for (const row of rows) {
        if (row.visualW === 0) {
          out.push(panelBlank(w, "accent", t));
        } else {
          out.push(panelRow(row.text, row.visualW, w, "accent", t));
        }
      }
      out.push(panelBlank(w, "accent", t));
      out.push(panelBottom(w, DISMISS_HINT, "accent", t));
      return out;
    },
    invalidate() {},
    handleInput() { done(); },
  };
}

// ─── Overlay display ────────────────────────────────────────────────────────

type PiComponent = ReturnType<typeof makeNudgeComponent>;
type ComponentFactory = (t: TuiTheme, done: () => void) => PiComponent;

async function showOverlay(
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  ctx: Record<string, any>,
  factory: ComponentFactory,
  innerW: number,
  fallbackText: string,
  autoDismissMs: number,
): Promise<void> {
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const ui = ctx["ui"] as Record<string, any> | undefined;
  if (typeof ui?.["custom"] !== "function") {
    ui?.["notify"]?.(fallbackText, "info");
    return;
  }
  let dismiss: (() => void) | undefined;
  const p = ui["custom"](
    // eslint-disable-next-line @typescript-eslint/no-explicit-any
    (_tui: unknown, theme: Record<string, any>, _kb: unknown, done: () => void) => {
      dismiss = done;
      return factory(theme as unknown as TuiTheme, done);
    },
    {
      overlay: true,
      overlayOptions: { anchor: "center", width: innerW + 4 },
    },
  ) as Promise<void>;
  const timer = setTimeout(() => dismiss?.(), autoDismissMs);
  try { await p; } finally { clearTimeout(timer); }
}

async function showNudgeOverlay(
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  ctx: Record<string, any>,
  text: string,
  autoDismissMs: number,
): Promise<void> {
  await showOverlay(
    ctx,
    (t, done) => makeNudgeComponent(text, t, done),
    NUDGE_INNER_W,
    text,
    autoDismissMs,
  );
}

// ─── Pi Extension Factory ──────────────────────────────────────────────────

export default function (pi: ExtensionAPI) {
  const sessionStart = Date.now();
  const skillsUsed: string[] = [];

  pi.on("input", async (event) => {
    if (!getWorkspaceState().isActive) return { action: "continue" as const };
    const match = event.text.match(/^\/skill:(\w+)/);
    if (match && !skillsUsed.includes(match[1])) {
      skillsUsed.push(match[1]);
    }
    return { action: "continue" as const };
  });

  pi.on("before_agent_start", async (_event, ctx) => {
    if (!getWorkspaceState().isActive) return;
    const elapsed = Math.round((Date.now() - sessionStart) / 60_000);
    if (elapsed > 0 && elapsed % 180 === 0) {
      await showNudgeOverlay(
        ctx as unknown as Record<string, unknown>,
        `🐠 You've been at this for ${elapsed} minutes.\n\nTake a short break — your brain consolidates learning during rest, not during grinding.`,
        9000,
      );
    }
  });

  pi.on("session_shutdown", async () => {
    if (!getWorkspaceState().isActive) return;
    const durationMinutes = Math.round((Date.now() - sessionStart) / 60_000);
    run({ sessionDurationMinutes: durationMinutes, skillsUsed });
  });

  pi.registerCommand("progress", {
    description: "Show this week's study summary and streak",
    handler: async (_args, ctx) => {
      if (!getWorkspaceState().isActive) {
        ctx.ui.notify("Activate a Pisces workspace first (/pisces --activate).", "warning");
        return;
      }
      const sessions = loadSessions();
      const stats = getWeeklyStats(sessions);
      await showOverlay(
        ctx as unknown as Record<string, unknown>,
        (t, done) => makeProgressComponent(stats, t, done),
        PROGRESS_INNER_W,
        buildWeeklySummary(stats),
        14000,
      );
    },
  });
}

// ─── Pi Extension Entry Point ──────────────────────────────────────────────

export function run(context: {
  sessionDurationMinutes: number;
  skillsUsed: string[];
  topicsWorked?: string[];
}): { nudge: string | null; weeklySummary: string } {
  const sessions = loadSessions();

  const record: SessionRecord = {
    date: new Date().toISOString(),
    durationMinutes: context.sessionDurationMinutes,
    skillsUsed: context.skillsUsed,
    topicsWorked: context.topicsWorked ?? [],
  };

  sessions.push(record);
  saveSessions(sessions);

  const stats = getWeeklyStats(sessions);
  const nudge = getBurnoutNudge(context.sessionDurationMinutes, stats);
  const weeklySummary = buildWeeklySummary(stats);

  return { nudge, weeklySummary };
}