package itglue

import (
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
)

type Metadata struct {
	CurrentPage int         `json:"current-page"`
	NextPage    interface{} `json:"next-page"`
	PrevPage    interface{} `json:"prev-page"`
	TotalPages  int         `json:"total-pages"`
	TotalCount  int         `json:"total-count"`
	Filters     struct {
	} `json:"filters"`
}

//ITGAPI contains the ITG API URL for North America, as well as the API key.
//Think of it as an instance of the API client
type ITGAPI struct {
	Site   string //Full URL ITG API
	APIKey string //API Key
}

//NewITGAPI expects the API key to be passed to it
//Returns a pointer to an ITGAPI struct
func NewITGAPI(apiKey string) *ITGAPI {
	return &ITGAPI{Site: "https://api.itglue.com", APIKey: apiKey}
}

func getHTTPResponseBody(resp *http.Response) ([]byte, error) {
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("ITG returned HTTP status code %s\n%s", resp.Status, resp.Body)
	}

	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("could not read http response body: %s", err)
	}

	return body, nil
}

//BuildURL expects a restaction to be passed to it
//Returns the full request URL containing the ITG API domain prepended to the rest action
func (itg *ITGAPI) BuildURL(restAction string) (*url.URL, error) {
	var itgurl *url.URL
	itgurl, err := url.Parse(itg.Site)
	if err != nil {
		return nil, fmt.Errorf("could not parse url %s: %s", itg.Site, err)
	}
	itgurl.Path += restAction
	return itgurl, nil
}

//GetRequest allows a custom GET request to the API to be made.
//Also used internally by this package by the binding functions
//Expects URL to be passed
//Returns the response body as a byte slice
func (itg *ITGAPI) GetRequest(itgurl *url.URL) ([]byte, error) {
	client := &http.Client{}
	req, err := http.NewRequest("GET", itgurl.String(), nil)
	if err != nil {
		return nil, fmt.Errorf("could not create http request: %s", err)
	}
	req.Header.Set("Content-Type", "application/vnd.api+json")
	req.Header.Set("x-api-key", itg.APIKey)
	req.Header.Set("cache-control", "no-cache")
	response, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("http request failed: %s", err)
	}
	defer response.Body.Close()

	return getHTTPResponseBody(response)
}

//PostRequest allows a custom POST request tot he API to be made
//Also used internally by this package by the binding functions
//Expects a URL and a body to be passed
//Returns the response body as a byte slice
func (itg *ITGAPI) PostRequest(itgurl *url.URL, body io.Reader) ([]byte, error) {
	client := &http.Client{}
	req, err := http.NewRequest("POST", itgurl.String(), body)
	if err != nil {
		return nil, fmt.Errorf("could not create http request: %s", err)
	}
	req.Header.Set("Content-Type", "application/vnd.api+json")
	req.Header.Set("x-api-key", itg.APIKey)
	req.Header.Set("cache-control", "no-cache")
	response, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("http request failed: %s", err)
	}
	defer response.Body.Close()

	return getHTTPResponseBody(response)

}

//PatchRequest allows a custom PATCH request tot he API to be made
//Also used internally by this package by the binding functions
//Expects a URL and a body to be passed
//Returns the response body as a byte slice
func (itg *ITGAPI) PatchRequest(itgurl *url.URL, body io.Reader) ([]byte, error) {
	client := &http.Client{}
	req, err := http.NewRequest("PATCH", itgurl.String(), body)
	if err != nil {
		return nil, fmt.Errorf("could not create http request: %s", err)
	}
	req.Header.Set("Content-Type", "application/vnd.api+json")
	req.Header.Set("x-api-key", itg.APIKey)
	req.Header.Set("cache-control", "no-cache")
	response, err := client.Do(req)
	if err != nil {
		return nil, fmt.Errorf("http request failed: %s", err)
	}
	defer response.Body.Close()

	return getHTTPResponseBody(response)

}