import { DirectiveTransform } from '../transform'
import { createObjectProperty, createSimpleExpression, NodeTypes } from '../ast'
import { createCompilerError, ErrorCodes } from '../errors'
import { camelize } from '@vue/shared'
import { CAMELIZE } from '../runtimeHelpers'

// v-bind without arg is handled directly in ./element.ts due to it affecting
// codegen for the entire props object. This transform here is only for v-bind
// *with* args.
export const transformBind: DirectiveTransform = (dir, context) => {
  const { exp, modifiers, loc } = dir
  const arg = dir.arg!
  if (!exp) {
    context.onError(createCompilerError(ErrorCodes.X_V_BIND_NO_EXPRESSION, loc))
  }
  // .prop is no longer necessary due to new patch behavior
  // .sync is replaced by v-model:arg
  if (modifiers.includes('camel')) {
    if (arg.type === NodeTypes.SIMPLE_EXPRESSION) {
      if (arg.isStatic) {
        arg.content = camelize(arg.content)
      } else {
        arg.content = `${context.helperString(CAMELIZE)}(${arg.content})`
      }
    } else {
      arg.children.unshift(`${context.helperString(CAMELIZE)}(`)
      arg.children.push(`)`)
    }
  }
  return {
    props: createObjectProperty(
      arg!,
      exp || createSimpleExpression('', true, loc)
    ),
    needRuntime: false
  }
}