Restructured code, moved all modules into internal

For now all modules are considered internal. This might change later

internal/backends/deezer/client.go

@@ -0,0 +1,89 @@
+/*
+Copyright © 2023 Philipp Wolfer <phw@uploadedlobster.com>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+*/
+
+package deezer
+
+import (
+	"errors"
+	"strconv"
+
+	"github.com/go-resty/resty/v2"
+	"golang.org/x/oauth2"
+)
+
+const baseURL = "https://api.deezer.com/"
+const MaxItemsPerGet = 1000
+const DefaultRateLimitWaitSeconds = 5
+
+type Client struct {
+	HttpClient *resty.Client
+	token      oauth2.TokenSource
+}
+
+func NewClient(token oauth2.TokenSource) Client {
+	client := resty.New()
+	client.SetBaseURL(baseURL)
+	client.SetHeader("Accept", "application/json")
+	client.SetRetryCount(5)
+	return Client{
+		HttpClient: client,
+		token:      token,
+	}
+}
+
+func (c Client) UserHistory(offset int, limit int) (result HistoryResult, err error) {
+	const path = "/user/me/history"
+	return listRequest[HistoryResult](c, path, offset, limit)
+}
+
+func (c Client) UserTracks(offset int, limit int) (TracksResult, error) {
+	const path = "/user/me/tracks"
+	return listRequest[TracksResult](c, path, offset, limit)
+}
+
+func (c Client) setToken(req *resty.Request) error {
+	tok, err := c.token.Token()
+	if err != nil {
+		return err
+	}
+
+	req.SetQueryParam("access_token", tok.AccessToken)
+	return nil
+}
+
+func listRequest[T Result](c Client, path string, offset int, limit int) (result T, err error) {
+	request := c.HttpClient.R().
+		SetQueryParams(map[string]string{
+			"index": strconv.Itoa(offset),
+			"limit": strconv.Itoa(limit),
+		}).
+		SetResult(&result)
+	c.setToken(request)
+	response, err := request.Get(path)
+
+	if response.StatusCode() != 200 {
+		err = errors.New(response.String())
+	} else if result.Error() != nil {
+		err = errors.New(result.Error().Message)
+	}
+	return
+}