/**
 * pi-shimmer-quotes-spinner — Quotes module
 *
 * Loads, parses, and manages the quote rotation.
 * Quotes come from a user-editable file or built-in defaults.
 */

import { existsSync, mkdirSync, readFileSync, writeFileSync } from "node:fs";
import { dirname, join } from "node:path";
import { getQuotesFileDir } from "./config";

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

export interface LoadedQuotes {
  quotes: string[];
  source: "user" | "bundled" | "fallback";
}

// ─── Built-in Default Quotes ───────────────────────────────────────────

const DEFAULT_QUOTES: string[] = [
  "Simplicity is prerequisite for reliability. — Edsger W. Dijkstra",
  "Programs must be written for people to read. — Harold Abelson",
  "Debugging is twice as hard as writing the code in the first place. — Brian Kernighan",
  "First, solve the problem. Then, write the code. — John Johnson",
  "Code is like humor. When you have to explain it, it's bad. — Cory House",
  "Make it work, make it right, make it fast. — Kent Beck",
  "Any fool can write code that a computer can understand. — Martin Fowler",
  "Talk is cheap. Show me the code. — Linus Torvalds",
  "Premature optimization is the root of all evil. — Donald Knuth",
  "The only way to learn a new programming language is by writing programs in it. — Dennis Ritchie",
  "Measuring programming progress by lines of code is like measuring aircraft building progress by weight. — Bill Gates",
  "There are only two hard things in computer science: cache invalidation and naming things. — Phil Karlton",
  "If you can't explain it simply, you don't understand it well enough. — Albert Einstein",
  "The most dangerous phrase in language is: we've always done it this way. — Grace Hopper",
  "The function of good software is to make the complex appear to be simple. — Grady Booch",
  "A language that doesn't affect the way you think about programming is not worth knowing. — Alan Perlis",
  "Sometimes it pays to stay in bed on Monday, rather than spending the rest of the week debugging Monday's code. — Dan Salomon",
  "The best time to plant a tree was 20 years ago. The second best time is now. — Chinese Proverb",
  "It's not a bug — it's an undocumented feature. — Anonymous",
  "Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live. — John Woods",
  "Fix the cause, not the symptom. — Steve Maguire",
  "A good programmer is someone who always looks both ways before crossing a one-way street. — Doug Linder",
  "Walking on water and developing software from a specification are easy if both are frozen. — Edward V. Berard",
  "Before software can be reusable it first has to be usable. — Ralph Johnson",
  "The best way to get a project done faster is to start sooner. — Jim Highsmith",
  "The best performance improvement is the transition from the nonworking to the working state. — John Ousterhout",
];

const FALLBACK_QUOTE = "Simplicity is prerequisite for reliability. — Edsger W. Dijkstra";

// ─── Paths ──────────────────────────────────────────────────────────────

export function getUserQuotesFile(): string {
  return join(getQuotesFileDir(), "quotes.txt");
}

// ─── Parsing ────────────────────────────────────────────────────────────

function parseQuotes(text: string): string[] {
  return text
    .split(/\r?\n/)
    .map((l) => l.trim())
    .filter((l) => l.length > 0 && !l.startsWith("#"));
}

// ─── Loading ────────────────────────────────────────────────────────────

/**
 * Load quotes from disk.  Priority:
 * 1. User quotes file (if it exists and has content)
 * 2. Built-in defaults (if enableFallback is true)
 * 3. Single hard-coded fallback quote
 */
export function loadQuotes(enableFallback: boolean): LoadedQuotes {
  const userFile = getUserQuotesFile();

  try {
    if (existsSync(userFile)) {
      const parsed = parseQuotes(readFileSync(userFile, "utf8"));
      if (parsed.length > 0) return { quotes: parsed, source: "user" };
    }
  } catch {
    // Fall through
  }

  if (enableFallback) {
    return { quotes: [...DEFAULT_QUOTES], source: "bundled" };
  }

  return { quotes: [FALLBACK_QUOTE], source: "fallback" };
}

/**
 * Ensure the user quotes file exists, seeding it with bundled defaults if
 * it doesn't.  Returns the file path.
 */
export function ensureUserQuotesFile(): string {
  const file = getUserQuotesFile();
  if (!existsSync(file)) {
    mkdirSync(dirname(file), { recursive: true });
    writeFileSync(
      file,
      [
        "# pi-shimmer-quotes-spinner — Custom Quotes",
        "# One quote per line.  Blank lines and lines starting with # are ignored.",
        "# Edit this file then run /shimmer quotes reload to apply changes.",
        "",
        ...DEFAULT_QUOTES,
      ].join("\n") + "\n",
      "utf8",
    );
  }
  return file;
}

// ─── Rotation ───────────────────────────────────────────────────────────

/**
 * Pick a random quote from the loaded set.
 */
export function pickQuote(loaded: LoadedQuotes): string {
  const pool = loaded.quotes;
  return pool[Math.floor(Math.random() * pool.length)] ?? FALLBACK_QUOTE;
}

// ─── Display Helpers ───────────────────────────────────────────────────

export function describeQuotes(loaded: LoadedQuotes): string {
  switch (loaded.source) {
    case "user":
      return `${loaded.quotes.length} User Quote${loaded.quotes.length !== 1 ? "s" : ""}`;
    case "bundled":
      return `${loaded.quotes.length} Built-in Quote${loaded.quotes.length !== 1 ? "s" : ""}`;
    case "fallback":
      return "Fallback Quote (no quotes loaded)";
  }
}