package grafana

import (
	"encoding/json"
	"io"
	"net/http"
	"strconv"
)

type DatasourcesInterface interface {
	All() ([]GrafanaDatasource, error)
	Create(datasourceJson io.Reader) error
	Delete(id int) error
}

// DatasourcesClient is an implementation of the DatasourcesInterface. The
// datasources HTTP API of Grafana requires admin access.
type DatasourcesClient struct {
	BaseUrl    string
	HTTPClient *http.Client
}

type GrafanaDatasource struct {
	Id   int    `json:"id"`
	Name string `json:"name"`
}

func NewDatasourcesClient(baseUrl string, c *http.Client) DatasourcesInterface {
	return &DatasourcesClient{
		BaseUrl:    baseUrl,
		HTTPClient: c,
	}
}

func (c *DatasourcesClient) All() ([]GrafanaDatasource, error) {
	allUrl := c.BaseUrl + "/api/datasources"
	resp, err := c.HTTPClient.Get(allUrl)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	datasources := make([]GrafanaDatasource, 0)

	err = json.NewDecoder(resp.Body).Decode(&datasources)
	if err != nil {
		return nil, err
	}

	return datasources, nil
}

func (c *DatasourcesClient) Delete(id int) error {
	deleteUrl := c.BaseUrl + "/api/datasources/" + strconv.Itoa(id)
	req, err := http.NewRequest("DELETE", deleteUrl, nil)
	if err != nil {
		return err
	}

	_, err = c.HTTPClient.Do(req)
	if err != nil {
		return err
	}

	return nil
}

func (c *DatasourcesClient) Create(datasourceJson io.Reader) error {
	createUrl := c.BaseUrl + "/api/datasources"
	_, err := c.HTTPClient.Post(createUrl, "application/json", datasourceJson)
	if err != nil {
		return err
	}

	return nil
}