var _ = require('./index')

/**
 * Check if an element is a component, if yes return its
 * component id.
 *
 * @param {Element} el
 * @param {Object} options
 * @return {String|undefined}
 */

exports.commonTagRE = /^(div|p|span|img|a|b|i|br|ul|ol|li|h1|h2|h3|h4|h5|h6|code|pre|table|th|td|tr|form|label|input|select|option)$/
exports.checkComponent = function (el, options) {
  var tag = el.tagName.toLowerCase()
  if (tag === 'component') {
    // dynamic syntax
    var exp = el.getAttribute('is')
    if (exp != null) {
      el.removeAttribute('is')
    } else {
      exp = el.getAttribute('bind-is')
      if (exp != null) {
        // leverage literal dynamic for now.
        // TODO: make this cleaner
        exp = '{{' + exp + '}}'
        el.removeAttribute('bind-is')
      }
    }
    return exp
  } else if (!exports.commonTagRE.test(tag)) {
    if (_.resolveAsset(options, 'components', tag)) {
      return tag
    } else if (process.env.NODE_ENV !== 'production') {
      if (tag.indexOf('-') > -1 ||
          /HTMLUnknownElement/.test(Object.prototype.toString.call(el))) {
        _.warn(
          'Unknown custom element: <' + tag + '> - did you ' +
          'register the component correctly?'
        )
      }
    }
  }
  /* eslint-disable no-cond-assign */
  if (tag = _.attr(el, 'component')) {
  /* eslint-enable no-cond-assign */
    return tag
  }
}

/**
 * Set a prop's initial value on a vm and its data object.
 *
 * @param {Vue} vm
 * @param {Object} prop
 * @param {*} value
 */

exports.initProp = function (vm, prop, value) {
  if (exports.assertProp(prop, value)) {
    var key = prop.path
    vm[key] = vm._data[key] = value
  }
}

/**
 * Assert whether a prop is valid.
 *
 * @param {Object} prop
 * @param {*} value
 */

exports.assertProp = function (prop, value) {
  // if a prop is not provided and is not required,
  // skip the check.
  if (prop.raw === null && !prop.required) {
    return true
  }
  var options = prop.options
  var type = options.type
  var valid = true
  var expectedType
  if (type) {
    if (type === String) {
      expectedType = 'string'
      valid = typeof value === expectedType
    } else if (type === Number) {
      expectedType = 'number'
      valid = typeof value === 'number'
    } else if (type === Boolean) {
      expectedType = 'boolean'
      valid = typeof value === 'boolean'
    } else if (type === Function) {
      expectedType = 'function'
      valid = typeof value === 'function'
    } else if (type === Object) {
      expectedType = 'object'
      valid = _.isPlainObject(value)
    } else if (type === Array) {
      expectedType = 'array'
      valid = _.isArray(value)
    } else {
      valid = value instanceof type
    }
  }
  if (!valid) {
    process.env.NODE_ENV !== 'production' && _.warn(
      'Invalid prop: type check failed for ' +
      prop.path + '="' + prop.raw + '".' +
      ' Expected ' + formatType(expectedType) +
      ', got ' + formatValue(value) + '.'
    )
    return false
  }
  var validator = options.validator
  if (validator) {
    if (!validator.call(null, value)) {
      process.env.NODE_ENV !== 'production' && _.warn(
        'Invalid prop: custom validator check failed for ' +
        prop.path + '="' + prop.raw + '"'
      )
      return false
    }
  }
  return true
}

function formatType (val) {
  return val
    ? val.charAt(0).toUpperCase() + val.slice(1)
    : 'custom type'
}

function formatValue (val) {
  return Object.prototype.toString.call(val).slice(8, -1)
}