const getTargetNameLines = (targetName: string): string[] => {
  return [`  target '${targetName}' do`, '    inherit! :complete', '  end'];
};

/**
 * Ensure that we disable SWIFT_VERIFY_EMITTED_MODULE_INTERFACE option
 * and include -no-verify-emitted-module-interface in OTHER_SWIFT_FLAGS
 * for all targets in the pods project in order for consuming prebuilt RN
 * frameworks to work
 */
const getPrebuiltSettingsLines = (): string[] => {
  return `    installer.pods_project.targets.each do |t|
      t.build_configurations.each do |config|
        config.build_settings['SWIFT_VERIFY_EMITTED_MODULE_INTERFACE'] = 'NO'
        flags = config.build_settings['OTHER_SWIFT_FLAGS'] || '$(inherited)'
        config.build_settings['OTHER_SWIFT_FLAGS'] = "#{flags} -no-verify-emitted-module-interface"
      end
    end`.split('\n');
};

const MANGLE_REQUIRE_MARKER =
  "require File.join(File.dirname(`node --print \"require.resolve('expo-brownfield/package.json')\"`), 'scripts/ios/mangle')";
const MANGLE_RUN_MARKER = 'ExpoBrownfield::Mangle.run!';

const getMangleRunLines = (targetName: string): string[] => {
  return [
    `    ExpoBrownfield::Mangle.run!(installer, targets: ['${targetName}'], mangle_prefix: '${targetName}_')`,
  ];
};

/**
 * Wire up expo-brownfield's bundled mangling logic in the Podfile.
 * Replaces the third-party `cocoapods-mangle` gem so users don't need a
 * Gemfile entry. Two insertions:
 *   1. A `require` line near the top of the Podfile that loads
 *      `scripts/ios/mangle.rb` from the expo-brownfield npm package.
 *   2. A `ExpoBrownfield::Mangle.run!(installer, ...)` call inside the
 *      `post_install` block (created if absent) that invokes the
 *      bundled Node worker to generate the mangling xcconfig.
 *
 * Both insertions are idempotent — re-running prebuild against an already
 * patched Podfile is a no-op.
 */
export const addManglePlugin = (podfile: string, targetName: string): string => {
  let result = addMangleRequire(podfile);
  result = addMangleRunCall(result, targetName);
  return result;
};

const addMangleRequire = (podfile: string): string => {
  if (podfile.includes(MANGLE_REQUIRE_MARKER)) {
    return podfile;
  }

  const lines = podfile.split('\n');
  // Insert after the last existing `require ` line (typically the
  // react_native_pods/autolinking requires) so we sit alongside them.
  const lastRequireIndex = lines.reduce((acc, line, index) => {
    if (line.trimStart().startsWith('require ')) {
      return index;
    }
    return acc;
  }, -1);

  const insertAt = lastRequireIndex >= 0 ? lastRequireIndex + 1 : 0;
  lines.splice(insertAt, 0, MANGLE_REQUIRE_MARKER);
  return lines.join('\n');
};

/**
 * Count Ruby block-opening keywords on `line` (after stripping `#` comments).
 * Recognizes `do` (with or without `|args|`) anywhere on the line, plus the
 * keywords `if/unless/while/until/case/begin/def/class/module/for` *only*
 * when they appear at the start of the line — that excludes the trailing-
 * modifier forms (`puts x if y`, `… while cond`) which don't take a matching
 * `end`. Strings and regexes containing the literal text `do`/`end` would
 * still be miscounted; Podfiles in practice don't put block keywords inside
 * string literals, so this is good enough for our scope.
 */
const countBlockOpens = (line: string): number => {
  const stripped = line.replace(/#.*$/, '');
  let opens = 0;
  const doMatches = stripped.match(/\bdo\b/g);
  if (doMatches) {
    opens += doMatches.length;
  }
  if (/^\s*(?:if|unless|while|until|case|begin|def|class|module|for)\b/.test(stripped)) {
    opens += 1;
  }
  return opens;
};

const countBlockCloses = (line: string): number => {
  const stripped = line.replace(/#.*$/, '');
  const matches = stripped.match(/\bend\b/g);
  return matches ? matches.length : 0;
};

/**
 * Find the matching `end` for the block whose opener is on `openerIndex`.
 * Walks forward tracking nesting depth so nested `do…end` (or `if…end`,
 * `case…end`, …) inside the block don't get mistaken for the outer block's
 * closer. Returns -1 if the input is unbalanced.
 */
const findMatchingEnd = (lines: string[], openerIndex: number): number => {
  let depth = 0;
  for (let i = openerIndex; i < lines.length; i++) {
    const line = lines[i] ?? '';
    depth += countBlockOpens(line);
    depth -= countBlockCloses(line);
    if (depth === 0 && i > openerIndex) {
      return i;
    }
  }
  return -1;
};

const addMangleRunCall = (podfile: string, targetName: string): string => {
  if (podfile.includes(MANGLE_RUN_MARKER)) {
    return podfile;
  }

  const runLines = getMangleRunLines(targetName);
  const lines = podfile.split('\n');

  const postInstallIndex = lines.findIndex((line) => line.includes('post_install do |installer|'));

  if (postInstallIndex === -1) {
    // No post_install block exists yet — append one at the bottom.
    lines.push('', 'post_install do |installer|', ...runLines, 'end');
    return lines.join('\n');
  }

  const blockEnd = findMatchingEnd(lines, postInstallIndex);
  if (blockEnd === -1) {
    return podfile;
  }

  lines.splice(blockEnd, 0, ...runLines);
  return lines.join('\n');
};

export const addNewPodsTarget = (podfile: string, targetName: string): string => {
  const targetLines = getTargetNameLines(targetName);
  let podFileLines = podfile.split('\n');
  if (podFileLines.find((line) => targetLines[0] != null && line.includes(targetLines[0].trim()))) {
    console.info(`Target for ${targetName} is already added. Skipping...`);
    return podfile;
  }

  const insertBefore = podFileLines.findLastIndex((line) => line === 'end');
  podFileLines = [
    ...podFileLines.slice(0, insertBefore),
    '', // new line for nicer output
    ...targetLines,
    ...podFileLines.slice(insertBefore),
  ];

  return podFileLines.join('\n');
};

export const addPrebuiltSettings = (podfile: string): string => {
  const prebuiltSettingsLines = getPrebuiltSettingsLines();
  let podFileLines = podfile.split('\n');

  if (
    podFileLines.find(
      (line) => prebuiltSettingsLines[4] != null && line.includes(prebuiltSettingsLines[4].trim())
    )
  ) {
    console.info('Prebuilt settings are already added. Skipping...');
    return podfile;
  }

  const postInstallIndex = podFileLines.findIndex((line) =>
    line.includes('post_install do |installer|')
  );
  const insertBefore = podFileLines.findIndex(
    (line, index) => line.includes('end') && index > postInstallIndex
  );
  podFileLines = [
    ...podFileLines.slice(0, insertBefore),
    '', // new line for nicer output
    ...prebuiltSettingsLines,
    ...podFileLines.slice(insertBefore),
  ];

  return podFileLines.join('\n');
};