/**
 * pi-shimmer-quotes-spinner — Renderer module
 *
 * Combines the spinner verb, shimmer effect, status information, and
 * optional quote into a single working-message string suitable for
 * `ctx.ui.setWorkingMessage()`.
 *
 * Adapts to narrow terminals by truncating the quote.
 */

import type { SQConfig } from "./config";
import { colorSweep, staticColor } from "./spinner";

// ─── Colour Palettes Per Intensity ─────────────────────────────────────

interface IntensityColors {
  verbBase: string;    // base verb colour
  verbShimmer: string; // peak shimmer highlight
  dimText: string;     // status / quote foreground
}

const PALETTE: Record<SQConfig["textIntensity"], IntensityColors> = {
  dim: {
    verbBase: "#B8865C",
    verbShimmer: "#D4A574",
    dimText: "#777777",
  },
  normal: {
    verbBase: "#D77757",
    verbShimmer: "#F59575",
    dimText: "#999999",
  },
  bright: {
    verbBase: "#FF9A6C",
    verbShimmer: "#FFB896",
    dimText: "#BBBBBB",
  },
};

// ─── ANSI-Aware Character Width Utilities ──────────────────────────────

/** Strip ANSI escape codes from a string. */
function ansiStrip(text: string): string {
  return text.replace(/\x1b\[[0-9;:]+[a-zA-Z]/g, "");
}

function isWideCodePoint(code: number): boolean {
  return (
    (code >= 0x1100 && code <= 0x115f) || // Hangul Jamo
    (code >= 0x2e80 && code <= 0xa4cf) || // CJK radicals → Yi
    (code >= 0xac00 && code <= 0xd7a3) || // Hangul syllables
    (code >= 0xf900 && code <= 0xfaff) || // CJK compatibility ideographs
    (code >= 0xfe30 && code <= 0xfe4f) || // CJK compatibility forms
    (code >= 0xff01 && code <= 0xff60) || // Fullwidth forms
    (code >= 0xffe0 && code <= 0xffe6) || // Fullwidth signs
    (code >= 0x1f300 && code <= 0x1faff) || // Emoji & symbols
    (code >= 0x20000 && code <= 0x3fffd) // CJK extensions B+
  );
}

/** Visible width of a string (accounting for CJK / emoji). */
export function displayWidth(text: string): number {
  let w = 0;
  for (const char of text) {
    const cp = char.codePointAt(0) ?? 0;
    if (cp === 0x200b || cp === 0x200d || cp === 0xfe0f || (cp >= 0x0300 && cp <= 0x036f)) {
      continue;
    }
    w += isWideCodePoint(cp) ? 2 : 1;
  }
  return w;
}

/**
 * Truncate `text` so its visible width ≤ `maxWidth`, appending an ellipsis.
 */
function truncateToWidth(text: string, maxWidth: number, ellipsis = "…"): string {
  if (displayWidth(text) <= maxWidth) return text;
  let result = "";
  let w = 0;
  const ew = displayWidth(ellipsis);
  for (const char of text) {
    const cw = isWideCodePoint(char.codePointAt(0) ?? 0) ? 2 : 1;
    if (w + cw + ew > maxWidth) break;
    result += char;
    w += cw;
  }
  return result + ellipsis;
}

// ─── Terminal Width Detection ──────────────────────────────────────────

/**
 * Return usable terminal content width.
 * The loader's Text component adds ~2 columns of padding.
 */
export function terminalWidth(): number {
  return Math.max(20, (process.stdout.columns ?? 80) - 2);
}

// ─── Message Builder ───────────────────────────────────────────────────

export interface BuildMessageParams {
  /** Current verb (e.g. "Brewing") */
  verb: string;
  /** Shimmer animation frame index */
  shimmerFrame: number;
  /** Active configuration */
  config: SQConfig;
  /** Status segments — elapsed time, token count, thinking state */
  statusParts: string[];
  /** Current quote text (or null to skip) */
  quote: string | null;
}

/**
 * Build the complete working-message string.
 *
 * Format (inline):
 *   Crunching…  (↓ 1,234 tokens · 32s)  "A quote here" — Author
 *
 * Format (multiline):
 *   Crunching…  (↓ 1,234 tokens · 32s)
 *     "A quote here" — Author
 *
 * Returns a plain string (no spinner glyph — that goes via
 * `setWorkingIndicator()`).
 */
export function buildWorkingMessage(params: BuildMessageParams): string {
  const { verb, shimmerFrame, config, statusParts, quote } = params;
  const palette = PALETTE[config.textIntensity] ?? PALETTE.normal;
  const RESET = "\x1b[0m";

  // ── Verb with optional shimmer ──────────────────────────────

  let verbText: string;
  if (config.enableShimmer) {
    verbText = colorSweep(verb + "…", shimmerFrame, palette.verbBase, palette.verbShimmer, true);
  } else {
    verbText = staticColor(verb + "…", palette.verbBase);
  }

  // ── Status portion ──────────────────────────────────────────

  const statusStr =
    statusParts.length > 0
      ? ` \x1b[38;2;${hexToRGB(palette.dimText)}m(${statusParts.join(" · ")})${RESET}`
      : "";

  // ── Quote portion ───────────────────────────────────────────

  if (quote && config.quoteMode === "inline") {
    const tw = terminalWidth();
    // Measure visible width of verb + status (strip ANSI first)
    const verbDisplay = displayWidth(verb) + 1; // "Brewing… "
    const statusDisplay = displayWidth(ansiStrip(statusStr));
    const padding = 4; // spaces around quote
    const available = Math.max(8, tw - verbDisplay - statusDisplay - padding);
    const truncated = truncateToWidth(quote, available);
    const styled = `\x1b[38;2;${hexToRGB(palette.dimText)}m${truncated}${RESET}`;
    return `${verbText}${statusStr}  ${styled}`;
  }

  if (quote && config.quoteMode === "multiline") {
    const tw = terminalWidth();
    const padLeft = Math.max(0, Math.floor((tw - displayWidth(quote)) / 2));
    const centered = `${" ".repeat(padLeft)}${quote}`;
    const styled = `\x1b[38;2;${hexToRGB(palette.dimText)}m${centered}${RESET}`;
    return `${verbText}${statusStr}\n${styled}`;
  }

  return `${verbText}${statusStr}`;
}

// ─── Internal ──────────────────────────────────────────────────────────

function hexToRGB(hex: string): string {
  const h = hex.replace("#", "");
  return `${parseInt(h.slice(0, 2), 16)};${parseInt(h.slice(2, 4), 16)};${parseInt(h.slice(4, 6), 16)}`;
}