package handlers

import (
  "fmt"
  "net/http"
  "encoding/xml"
  "github.com/samedi/caldav-go/lib"
  "github.com/samedi/caldav-go/global"
  "github.com/samedi/caldav-go/data"
  "github.com/samedi/caldav-go/ixml"
)

// Wraps a multistatus response. It contains the set of `Responses`
// that will serve to build the final XML. Multistatus responses are
// used by the REPORT and PROPFIND methods.
type multistatusResp struct {
  // The set of multistatus responses used to build each of the <DAV:response> nodes.
  Responses []msResponse
  // Flag that XML should be minimal or not
  // [defined in the draft https://tools.ietf.org/html/draft-murchison-webdav-prefer-05]
  Minimal bool
}

type msResponse struct {
  Href string
  Found bool
  Propstats msPropstats
}

type msPropstats map[int]msProps

// Adds a msProp to the map with the key being the prop status.
func (stats msPropstats) Add(prop msProp) {
  stats[prop.Status] = append(stats[prop.Status], prop)
}

func (stats msPropstats) Clone() msPropstats {
  clone := make(msPropstats)

  for k, v := range stats {
    clone[k] = v
  }

  return clone
}

type msProps []msProp

type msProp struct {
  Tag      xml.Name
  Content  string
  Contents []string
  Status   int
}

// Function that processes all the required props for a given resource.
// ## Params
// resource: the target calendar resource.
// reqprops: set of required props that must be processed for the resource.
// ## Returns
// The set of props (msProp) processed. Each prop is mapped to a HTTP status code.
// So if a prop is found and processed ok, it'll be mapped to 200. If it's not found,
// it'll be mapped to 404, and so on.
func (ms *multistatusResp) Propstats(resource *data.Resource, reqprops []xml.Name) msPropstats {
  if resource == nil {
    return nil
  }

  result := make(msPropstats)

  for _, ptag := range reqprops {
    pvalue := msProp{
      Tag: ptag,
      Status: http.StatusOK,
    }

    pfound := false
    switch ptag {
    case ixml.CALENDAR_DATA_TG:
      pvalue.Content, pfound = resource.GetContentData()
      if pfound {
        pvalue.Content = ixml.EscapeText(pvalue.Content)
      }
    case ixml.GET_ETAG_TG:
      pvalue.Content, pfound = resource.GetEtag()
    case ixml.GET_CONTENT_TYPE_TG:
      pvalue.Content, pfound = resource.GetContentType()
    case ixml.GET_CONTENT_LENGTH_TG:
      pvalue.Content, pfound = resource.GetContentLength()
    case ixml.DISPLAY_NAME_TG:
      pvalue.Content, pfound = resource.GetDisplayName()
      if pfound {
        pvalue.Content = ixml.EscapeText(pvalue.Content)
      }
    case ixml.GET_LAST_MODIFIED_TG:
      pvalue.Content, pfound = resource.GetLastModified(http.TimeFormat)
    case ixml.OWNER_TG:
      pvalue.Content, pfound = resource.GetOwnerPath()
    case ixml.GET_CTAG_TG:
      pvalue.Content, pfound = resource.GetEtag()
    case ixml.PRINCIPAL_URL_TG,
         ixml.PRINCIPAL_COLLECTION_SET_TG,
         ixml.CALENDAR_USER_ADDRESS_SET_TG,
         ixml.CALENDAR_HOME_SET_TG:
      pvalue.Content, pfound = ixml.HrefTag(resource.Path), true
    case ixml.RESOURCE_TYPE_TG:
      if resource.IsCollection() {
        pvalue.Content, pfound = ixml.Tag(ixml.COLLECTION_TG, "") + ixml.Tag(ixml.CALENDAR_TG, ""), true

        if resource.IsPrincipal() {
          pvalue.Content += ixml.Tag(ixml.PRINCIPAL_TG, "")
        }
      } else {
        // resourcetype must be returned empty for non-collection elements
        pvalue.Content, pfound = "", true
      }
    case ixml.CURRENT_USER_PRINCIPAL_TG:
      if global.User != nil {
        path := fmt.Sprintf("/%s/", global.User.Name)
        pvalue.Content, pfound = ixml.HrefTag(path), true
      }
    case ixml.SUPPORTED_CALENDAR_COMPONENT_SET_TG:
      if resource.IsCollection() {
        for _, component := range supportedComponents {
          // TODO: use ixml somehow to build the below tag
          compTag := fmt.Sprintf(`<C:comp name="%s"/>`, component)
          pvalue.Contents = append(pvalue.Contents, compTag)
        }
        pfound = true
      }
    }

    if !pfound {
      pvalue.Status = http.StatusNotFound
    }

    result.Add(pvalue)
  }

  return result
}

// Adds a new `msResponse` to the `Responses` array.
func (ms *multistatusResp) AddResponse(href string, found bool, propstats msPropstats) {
  ms.Responses = append(ms.Responses, msResponse{
    Href: href,
    Found: found,
    Propstats: propstats,
  })
}

func (ms *multistatusResp) ToXML() string {
  // init multistatus
  var bf lib.StringBuffer
  bf.Write(`<?xml version="1.0" encoding="UTF-8"?>`)
  bf.Write(`<D:multistatus %s>`, ixml.Namespaces())

  // iterate over event hrefs and build multistatus XML on the fly
  for _, response := range ms.Responses {
    bf.Write("<D:response>")
    bf.Write(ixml.HrefTag(response.Href))

    if response.Found {
      propstats := response.Propstats.Clone()

      if ms.Minimal {
        delete(propstats, http.StatusNotFound)

        if len(propstats) == 0 {
          bf.Write("<D:propstat>")
          bf.Write("<D:prop/>")
          bf.Write(ixml.StatusTag(http.StatusOK))
          bf.Write("</D:propstat>")
          bf.Write("</D:response>")

          continue
        }
      }

      for status, props := range propstats {
        bf.Write("<D:propstat>")
        bf.Write("<D:prop>")
        for _, prop := range props {
          bf.Write(ms.propToXML(prop))
        }
        bf.Write("</D:prop>")
        bf.Write(ixml.StatusTag(status))
        bf.Write("</D:propstat>")
      }
    } else {
      // if does not find the resource set 404
      bf.Write(ixml.StatusTag(http.StatusNotFound))
    }
    bf.Write("</D:response>")
  }
  bf.Write("</D:multistatus>")

  return bf.String()
}

func (ms *multistatusResp) propToXML(prop msProp) string {
  for _, content := range prop.Contents {
    prop.Content += content
  }
  xmlString := ixml.Tag(prop.Tag, prop.Content)
  return xmlString
}