/**
 * Clipboard via OSC 52.
 *
 * OSC 52 (`\x1b]52;c;<base64>\x07`) is an ANSI sequence that asks
 * the terminal emulator to set the system clipboard. It works in
 * iTerm2, kitty, Alacritty, WezTerm, modern Windows Terminal, and
 * tunnels naturally over SSH (the local terminal does the work, so
 * we don't need a remote helper). macOS Terminal.app needs the
 * "Allow applications on this Mac to access the clipboard" toggle.
 *
 * `c` selects the system clipboard (vs. `p` for primary selection
 * on X11). BEL (`\x07`) terminates the sequence — works in every
 * common terminal; some also accept ST (`\x1b\\`).
 */

import type { DriftFinding } from '../../services/audit/types';
import type { CommandLogEntry } from './audit-state';

/** Base64-encode UTF-8 input — Node/Bun's Buffer is the simplest path. */
function base64(text: string): string {
  return Buffer.from(text, 'utf8').toString('base64');
}

/**
 * Strip ANSI escape sequences (CSI color/style codes, OSC strings,
 * single-char escapes). Module output streamed into the command log
 * keeps its colors so the in-TUI render stays pretty, but pasting
 * those into a chat or issue tracker is just noise.
 *
 * Built from a string at runtime so biome's "control character in
 * regex" lint doesn't fire on a literal `\x1b` in source.
 */
const ESC = '\x1b';
const ANSI_PATTERN = new RegExp(
  // CSI: ESC [ ... letter, e.g. \x1b[34m, \x1b[2;3H
  `${ESC}\\[[0-9;?]*[A-Za-z]|` +
    // OSC: ESC ] ... BEL or ST
    `${ESC}\\][^${ESC}\\x07]*(?:${ESC}\\\\|\\x07)|` +
    // Single-char escapes
    `${ESC}[@-Z\\\\-_]`,
  'g',
);
function stripAnsi(text: string): string {
  return text.replace(ANSI_PATTERN, '');
}

/**
 * Copy `text` to the system clipboard via OSC 52.
 *
 * Writes directly to stdout — Ink's renderer doesn't mind extra
 * escape sequences interleaved between its frames. The terminal
 * intercepts OSC 52 before it reaches the Ink output.
 */
export function copyToClipboard(text: string): void {
  const seq = `\x1b]52;c;${base64(text)}\x07`;
  process.stdout.write(seq);
}

/**
 * Format a finding as plain text suitable for pasting into a chat,
 * issue tracker, or notes app. Mirrors the Detail pane's structure.
 * Strips ANSI codes from any field that might carry them (terraform
 * stderr in `details`, etc.) so the paste is clean text.
 */
export function formatFindingForClipboard(f: DriftFinding): string {
  const lines: string[] = [stripAnsi(f.message)];
  if (f.details) {
    lines.push('', stripAnsi(f.details));
  }
  if (f.remediation) {
    lines.push('', `→ ${stripAnsi(f.remediation)}`);
  }
  lines.push('', `${f.subject} · ${f.code} (${f.category}/${f.severity})`);
  return lines.join('\n');
}

/**
 * Format the entire command log as plain text suitable for pasting.
 * Mirrors the Command-log pane's rendering — separator headers,
 * stdout/stderr lines (`[err]` prefix on stderr to disambiguate
 * once colors are gone), and exit-code footers. ANSI escape codes
 * in streamed module output are stripped — they're useful in the
 * TUI but render as garbage when pasted elsewhere.
 */
export function formatCommandLogForClipboard(log: CommandLogEntry[]): string {
  if (log.length === 0) return '(empty)';
  const lines: string[] = [];
  for (const entry of log) {
    const time = new Date(entry.startedAt).toISOString();
    lines.push(`─── ${time} · ${entry.cmd} ───`);
    for (const ln of entry.lines) {
      const clean = stripAnsi(ln.text);
      lines.push(ln.stream === 'stderr' ? `[err] ${clean}` : clean);
    }
    lines.push(entry.exitCode === null ? 'running…' : `exit ${entry.exitCode}`);
    lines.push('');
  }
  // Drop the trailing blank line.
  if (lines[lines.length - 1] === '') lines.pop();
  return lines.join('\n');
}