/**
 * @author Toru Nagashima
 * @copyright 2017 Toru Nagashima. All rights reserved.
 * See LICENSE file in root directory for full license.
 */
'use strict'

// ------------------------------------------------------------------------------
// Requirements
// ------------------------------------------------------------------------------

const utils = require('../utils')

// ------------------------------------------------------------------------------
// Helpers
// ------------------------------------------------------------------------------

/**
 * Check whether the given `v-if` node is using the variable which is defined by the `v-for` directive.
 * @param {ASTNode} vIf The `v-if` attribute node to check.
 * @returns {boolean} `true` if the `v-if` is using the variable which is defined by the `v-for` directive.
 */
function isUsingIterationVar (vIf) {
  const element = vIf.parent.parent
  return vIf.value.references.some(reference =>
    element.variables.some(variable =>
      variable.id.name === reference.id.name &&
      variable.kind === 'v-for'
    )
  )
}

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

module.exports = {
  meta: {
    docs: {
      description: 'disallow confusing `v-for` and `v-if` on the same element',
      category: 'recommended',
      url: 'https://github.com/vuejs/eslint-plugin-vue/blob/v4.2.2/docs/rules/no-confusing-v-for-v-if.md'
    },
    fixable: null,
    schema: []
  },

  create (context) {
    return utils.defineTemplateBodyVisitor(context, {
      "VAttribute[directive=true][key.name='if']" (node) {
        const element = node.parent.parent

        if (utils.hasDirective(element, 'for') && !isUsingIterationVar(node)) {
          context.report({
            node,
            loc: node.loc,
            message: "This 'v-if' should be moved to the wrapper element."
          })
        }
      }
    })
  }
}
