import PassTransformationError from "@specs-feup/lara/api/lara/pass/PassTransformationError.js";
import SimplePass from "@specs-feup/lara/api/lara/pass/SimplePass.js";
import PassResult from "@specs-feup/lara/api/lara/pass/results/PassResult.js";
import {
  DeclStmt,
  FunctionJp,
  Joinpoint,
  StorageClass,
  Vardecl,
} from "../../Joinpoints.js";
import ClavaJoinPoints from "../ClavaJoinPoints.js";

/**
 * Transforms local static variables into global variables.
 *
 * This means that code like this:
 *
 * ```c
 * int foo() {
 *    static int x = 10;
 *    return x;
 * }
 * ```
 *
 * Will be transformed into:
 *
 * ```c
 * int foo_static_x = 10;
 *
 * int foo() {
 *    return foo_static_x;
 * }
 * ```
 */
export default class LocalStaticToGlobal extends SimplePass {
  protected _name = "LocalStaticToGlobal";

  matchJoinpoint($jp: Joinpoint): boolean {
    // Only vardecls
    if (!($jp instanceof Vardecl)) {
      return false;
    }

    // With static storage
    if ($jp.storageClass !== StorageClass.STATIC) {
      return false;
    }

    // Inside functions - not sure if this is needed
    if ($jp.getAncestor("function") === undefined) {
      return false;
    }

    return true;
  }

  transformJoinpoint($jp: Vardecl): PassResult {
    const $function = $jp.getAncestor("function") as FunctionJp | undefined;
    if (!$function) {
      throw new PassTransformationError(
        this,
        $jp,
        "Expected ancestor of type function, found 'undefined'"
      );
    }

    const newName = $function.name + "_static_" + $jp.name;

    $jp.name = newName;
    $jp.storageClass = StorageClass.NONE;

    const $declStmt = $jp.parent;
    if (!($declStmt instanceof DeclStmt)) {
      throw new PassTransformationError(
        this,
        $jp,
        "Expected declStmt, found '" + $declStmt.joinPointType + "'"
      );
    }

    $jp.detach();
    $function.insertBefore($jp);

    // Remove declStmt if empty
    if ($declStmt.decls.length === 0) {
      $declStmt.detach();
    }

    return new PassResult(this, ClavaJoinPoints.emptyStmt());
  }
}