import { Script } from "node:vm";

const JAVASCRIPT_EXPORT =
  /^export\s+(?:(?:abstract|as|async|class|const|declare|default|enum|function|import|interface|let|namespace|type|var)\b|[={*])/u;
const JAVASCRIPT_KEYWORD =
  /^(?:abstract|as|async|await|break|case|catch|class|const|continue|debugger|declare|default|delete|do|else|enum|export|extends|false|finally|for|function|if|implements|import|in|instanceof|interface|let|namespace|new|null|of|private|protected|public|return|satisfies|static|super|switch|this|throw|true|try|typeof|undefined|var|void|while|with|yield)$/u;
const JAVASCRIPT_GLOBAL =
  /^(?:ALL_TOOLS|AggregateError|Array|ArrayBuffer|BigInt|BigInt64Array|BigUint64Array|Boolean|DataView|Date|Error|EvalError|Float32Array|Float64Array|Function|Infinity|Int16Array|Int32Array|Int8Array|Intl|JSON|Map|Math|NaN|Number|Object|Promise|Proxy|RangeError|ReferenceError|Reflect|RegExp|Set|String|Symbol|SyntaxError|TypeError|URIError|Uint16Array|Uint32Array|Uint8Array|Uint8ClampedArray|WeakMap|WeakSet|console|decodeURI|decodeURIComponent|encodeURI|encodeURIComponent|eval|globalThis|isFinite|isNaN|parseFloat|parseInt|tools)$/u;

const SHELL_COMMAND =
  /^(?:\/(?:usr\/(?:local\/)?)?bin\/)?(alias|apt|awk|bash|bg|brew|builtin|bun|cargo|cat|cd|chmod|cmd|command|cp|curl|cut|date|declare|df|dir|docker|dotnet|du|echo|env|exec|exit|export|fg|file|find|getopts|git|go|gradle|grep|hash|head|help|hostname|id|java|javac|jobs|jq|kill|kubectl|ln|local|logout|ls|make|mkdir|mvn|mv|node|npm|npx|perl|php|pip|pip3|pnpm|poetry|popd|powershell|printf|ps|pushd|pwd|pwsh|pytest|python|python3|read|readonly|rg|rm|ruby|rustc|rustup|sed|set|sh|shift|sleep|sort|source|stat|sudo|swift|systemctl|tail|tar|tee|test|touch|trap|tree|type|ulimit|umask|uname|uniq|unset|unzip|uv|uvx|vitest|wait|wc|wget|which|whoami|xargs|yarn|zip|zsh)(?=$|[\s;&|<>])/u;

const SHELL_IDENTIFIER = /^([A-Za-z_][\w-]*)(?=$|[\s;&|<>])/u;
const SHELL_EXECUTABLE_PATH =
  /^(?:(?:\.{1,2}|~)[\\/]|\/|[A-Za-z]:[\\/])[^\s;|&()]+(?=$|[\t \r\n;&|])/u;
const SHELL_ARGUMENT =
  /^(?:-{1,2}[a-z\d][\w-]*(?:[\t =;&|]|$)|(?:(?:\.{1,2}|~)[\\/]|\/|[A-Za-z]:[\\/])[^\s]+)/iu;
const SHELL_ENV_ASSIGNMENT =
  /^[A-Za-z_]\w*=(?:"(?:\\.|[^"])*"|'[^']*'|\\.|[^\s;&|])*(?:[\t ]+|[\t ]*\r?\n[\t ]*)(?=\S)/u;
const SHELL_CONTROL =
  /^(?:(?:if|elif|while|until)[\t ]+(?:\[{1,2}(?=[\t ]|$)|test\b|[A-Za-z_][\w-]*(?=[\t ;]))|for[\t ]+(?:[A-Za-z_]\w*[\t ]+in\b|\(\([^\r\n]*\)\)[\t ]*;[\t ]*do\b)|case[\t ]+\S+[\t ]+in\b|function[\t ]+[A-Za-z_][\w-]*[\t ]*\{)/u;
const SHELL_REDIRECTION = /^(?:\d*(?:>>?|<<?)|&>>?)/u;
const LEADING_SOURCE_COMMENTS =
  /^(?:(?:\/\/[^\r\n]*(?:\r?\n|$)|\/\*[\s\S]*?\*\/|#[^\r\n]*(?:\r?\n|$))[\t \r\n]*)+/u;

function parsesAsGuestJavaScript(source: string, declaration = ""): boolean {
  try {
    return new Script(`(async () => {\n${declaration}${source}\n})`) instanceof Script;
  } catch {
    return false;
  }
}

function hasHoistedGuestBinding(source: string, name: string): boolean {
  // A lexical probe conflicts only with a real same-scope declaration; the
  // matching var probe succeeds only when that declaration is hoisted.
  return (
    !parsesAsGuestJavaScript(source, `let ${name};\n`) &&
    parsesAsGuestJavaScript(source, `var ${name};\n`)
  );
}

/** Reject recognizable shell commands without guessing at JavaScript expressions. */
export function isShellLikeCodeModeSource(source: string, preparedSource = source): boolean {
  const trimmed = source.trim();
  if (trimmed.startsWith("#!")) {
    return true;
  }
  const uncommented = trimmed.replace(LEADING_SOURCE_COMMENTS, "");
  if (!uncommented || JAVASCRIPT_EXPORT.test(uncommented)) {
    return false;
  }
  if (SHELL_CONTROL.test(uncommented)) {
    return true;
  }
  // Shell environment prefixes cannot make a recognizable executable safe;
  // strip them before deciding whether the guest worker should start.
  let commandSource = uncommented;
  for (;;) {
    const assignment = SHELL_ENV_ASSIGNMENT.exec(commandSource);
    if (!assignment) {
      break;
    }
    commandSource = commandSource.slice(assignment[0].length);
  }

  const knownCommand = SHELL_COMMAND.exec(commandSource);
  const unknownCommand = SHELL_IDENTIFIER.exec(commandSource);
  const command =
    knownCommand ??
    (unknownCommand &&
    !JAVASCRIPT_KEYWORD.test(unknownCommand[1] ?? "") &&
    !JAVASCRIPT_GLOBAL.test(unknownCommand[1] ?? "")
      ? unknownCommand
      : null);
  if (!command && !SHELL_EXECUTABLE_PATH.test(commandSource)) {
    return false;
  }

  const commandTail = command ? commandSource.slice(command[0].length) : "";
  const remainder = commandTail.trimStart();

  if (command && !remainder) {
    return knownCommand !== null;
  }

  // A binding only matters when the actual guest program parses. TypeScript
  // callers supply transformed JavaScript so shell text inside a comment,
  // string, or unrelated declaration cannot bypass source validation.
  if (!parsesAsGuestJavaScript(preparedSource)) {
    return true;
  }

  const commandName = command?.[1];
  if (commandName && hasHoistedGuestBinding(preparedSource, commandName)) {
    return false;
  }

  if (/^[\t ]*(?:[;\r\n]|&&?|\|{1,2})/u.test(commandTail)) {
    return knownCommand !== null;
  }

  if (
    !command ||
    (!SHELL_ARGUMENT.test(remainder) &&
      !(knownCommand !== null && SHELL_REDIRECTION.test(remainder)) &&
      !(commandName === "jq" && remainder.startsWith(".")))
  ) {
    return false;
  }

  // An unbound executable with flags or a path would only become a QuickJS
  // ReferenceError and trigger another model retry.
  return true;
}

export const CODE_MODE_SHELL_SOURCE_ERROR =
  "code-mode exec runs JavaScript or TypeScript, not shell commands. " +
  "Call shell, file, or other tools from guest JavaScript with " +
  "tools.callValue and an exact tool id from ALL_TOOLS or tools.search. " +
  "Do not retry the same shell command as code.";