const _ = require('lodash')

const httpMethods = ['get', 'put', 'post', 'delete', 'options', 'head', 'patch']

// Preprocessor for the swagger-json, so that some of the logic can be taken out of the
// template

module.exports = function(swaggerJson) {
  const copy = _.cloneDeep(swaggerJson)

  const tagsByName = _.keyBy(copy.tags, 'name')

  copy.tags = copy.tags || []

  // The "body"-parameter in each operation is stored in a
  // separate field "_request_body".
  if (copy.paths) {
    Object.keys(copy.paths).forEach(function(pathName) {
      const path = copy.paths[pathName]
      const pathParameters = path.parameters || []
      Object.keys(path).forEach(function(method) {
        if (httpMethods.indexOf(method) < 0) {
          delete path[method]
          return
        }
        const operation = path[method]
        operation.path = pathName
        operation.method = method
        // Draw links from tags to operations referencing them
        const operationTags = operation.tags || ['default']
        operationTags.forEach(function(tag) {
          if (!tagsByName[tag]) {
            // New implicit declaration of tag not defined in global "tags"-object
            // https://github.com/swagger-api/swagger-spec/blob/master/versions/2.0.md#user-content-swaggerTags
            const tagDefinition = {
              name: tag,
              operations: []
            }
            tagsByName[tag] = tagDefinition
            copy.tags.push(tagDefinition)
          }
          if (tagsByName[tag]) {
            tagsByName[tag].operations = tagsByName[tag].operations || []
            tagsByName[tag].operations.push(operation)
          }
        })
        // Join parameters with path-parameters
        operation.parameters = (operation.parameters || []).concat(pathParameters).filter(function(param) {
          if (param.in === 'body') {
            operation._request_body = param
            return false
          }
          return true
        })
        // Show body section, if either a body-parameter or a consumes-property is present.
        operation._show_requst_body_section = operation._request_body || operation.consumes
      })
    })
    // If there are multiple tags, we show the tag-based summary
    copy.showTagSummary = copy.tags.length > 1
  }
  return copy
}