import * as utils from "../../utils";
import { AST_NODE_TYPES } from "@typescript-eslint/utils";
import type { RuleListener } from "@typescript-eslint/utils/dist/ts-eslint";

export enum MessageId {
  triviallyInferrableType = "triviallyInferrableType"
}

export const noInferrableTypes = utils.createRule({
  name: "no-inferrable-types",
  messages: {
    [MessageId.triviallyInferrableType]:
      "Type can be trivially inferred from initializer"
  },
  docs: {
    description: "Reports inferrable types.",
    failExamples: `
      function f<T>() {
        const x: T = {} as T;
      }

    `,
    passExamples: `
      function f<T>() {
        const x = {} as T;
      }
    `
  },
  create: (context): RuleListener => {
    return {
      VariableDeclarator: node => {
        const { id, init } = node;

        if (
          id.typeAnnotation &&
          init &&
          init.type === AST_NODE_TYPES.TSAsExpression
        ) {
          const type1 = id.typeAnnotation.typeAnnotation;

          const type2 = init.typeAnnotation;

          const text1 = context.getText(type1);

          const text2 = context.getText(type2);

          if (text1 === text2)
            context.report({
              messageId: MessageId.triviallyInferrableType,
              node: type1
            });
        }
      }
    };
  }
});