/**
 * @fileoverview Rule to flag use of function declaration identifiers as variables.
 * @author Ian Christian Myers
 */

'use strict';

const astUtils = require('./utils/ast-utils');

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
  meta: {
    type: 'problem',

    docs: {
      description: 'Disallow reassigning `function` declarations',
      recommended: true,
      url: 'https://eslint.org/docs/latest/rules/no-func-assign',
    },

    schema: [],

    messages: {
      isAFunction: "'{{name}}' is a function.",
    },
  },

  create(context) {
    const sourceCode = context.sourceCode;

    /**
     * Reports a reference if is non initializer and writable.
     * @param {References} references Collection of reference to check.
     * @returns {void}
     */
    function checkReference(references) {
      astUtils.getModifyingReferences(references).forEach((reference) => {
        context.report({
          node: reference.identifier,
          messageId: 'isAFunction',
          data: {
            name: reference.identifier.name,
          },
        });
      });
    }

    /**
     * Finds and reports references that are non initializer and writable.
     * @param {Variable} variable A variable to check.
     * @returns {void}
     */
    function checkVariable(variable) {
      if (variable.defs[0].type === 'FunctionName') {
        checkReference(variable.references);
      }
    }

    /**
     * Checks parameters of a given function node.
     * @param {ASTNode} node A function node to check.
     * @returns {void}
     */
    function checkForFunction(node) {
      sourceCode.getDeclaredVariables(node).forEach(checkVariable);
    }

    return {
      FunctionDeclaration: checkForFunction,
      FunctionExpression: checkForFunction,
    };
  },
};