package databridge

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"

	"github.com/pkg/errors"
)

// Record represents a Data Bridge data record
type Record struct {
	ID   string      `json:"id"`
	Data interface{} `json:"data"`
}

// Data represents the data portion of a record, can be used on its own when publishing
type Data struct {
	Data interface{} `json:"data"`
}

// GetUnreadCount returns the count of unread records in the given topic in the context of the api key
func (c Client) GetUnreadCount() (*int32, error) {

	url := fmt.Sprintf("%s/topics/%s?api_key=%s", c.BaseURL, c.TopicSlug, c.APIKey)
	req, _ := http.NewRequest("GET", url, nil)
	req.Header.Add("content-type", "application/json")
	req.Header.Add("api_key", c.APIKey)

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, errors.Wrap(err, fmt.Sprintf("error making databridge http request for %s", url))
	}

	if res.StatusCode != 200 {
		return nil, errors.Wrap(err, fmt.Sprintf("databridge - error getting unread count for %s", url))
	}

	defer res.Body.Close()
	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return nil, errors.Wrap(err, "error trying to read databridge response body")
	}

	var js struct {
		Count int32 `json:"unread_records"`
	}

	err = json.Unmarshal([]byte(body), &js)
	if err != nil {
		return nil, errors.Wrap(err, "error trying to unmarshal response body to json")
	}

	return &js.Count, nil
}

// GetNextRecord returns the topic's next record.  Will return nil without an error when there are no more records.
func (c Client) GetNextRecord(consumerID string) (*Record, error) {
	url := fmt.Sprintf("%s/topics/%s/records/next?consumer_id=%s&api_key=%s", c.BaseURL, c.TopicSlug, consumerID, c.APIKey)
	req, _ := http.NewRequest("GET", url, nil)
	req.Header.Add("content-type", "application/json")
	req.Header.Add("api_key", c.APIKey)

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return nil, errors.Wrap(err, fmt.Sprintf("error making databridge http request for %s", url))
	}

	// capture 404 and return nils
	if res.StatusCode == 404 {
		return nil, nil
	}

	if res.StatusCode != 200 {
		return nil, errors.New(fmt.Sprintf("databridge responded with non-200 for %s", url))
	}

	defer res.Body.Close()
	body, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return nil, errors.Wrap(err, "error trying to read databridge response body")
	}

	var record Record

	err = json.Unmarshal([]byte(body), &record)
	if err != nil {
		return nil, errors.Wrap(err, "error trying to unmarshal response body to json")
	}

	return &record, nil
}

// Publish allows for the publishing of a record on the client's topic
func (c Client) Publish(d interface{}) error {
	url := fmt.Sprintf("%s/topics/%s/records?api_key=%s", c.BaseURL, c.TopicSlug, c.APIKey)

	// marshal body to byte array
	data := Data{Data: d}
	body, err := json.Marshal(data)
	if err != nil {
		return errors.Wrap(err, fmt.Sprintf("error marshaling json for data %v", d))
	}

	// make request
	req, _ := http.NewRequest("POST", url, bytes.NewBuffer(body))
	req.Header.Add("content-type", "application/json")
	req.Header.Add("api_key", c.APIKey)

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return errors.Wrap(err, fmt.Sprintf("error attempting to publish a record for %s", url))
	}

	if res.StatusCode != 201 {
		return errors.New(fmt.Sprintf("databridge publish record responded with non-201 for %s", url))
	}

	return nil
}

// CompleteRecord allows the record to be marked as completed
func (c Client) CompleteRecord(r Record) error {
	return r.updateRecordState(c, "completed")
}

// FailRecord allows the record to be marked as failed
func (c Client) FailRecord(r Record) error {
	return r.updateRecordState(c, "failed")
}

func (r Record) updateRecordState(c Client, state string) error {
	url := fmt.Sprintf("%s/records/%s/state/%s?api_key=%s", c.BaseURL, r.ID, state, c.APIKey)

	req, _ := http.NewRequest("PUT", url, nil)
	req.Header.Add("content-type", "application/json")
	req.Header.Add("api_key", c.APIKey)

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return errors.Wrap(err, fmt.Sprintf("error attempting to update databridge record state for %s", url))
	}

	if res.StatusCode != 200 {
		return errors.New(fmt.Sprintf("databridge update record state responded with non-200 for %s", url))
	}

	return nil
}