Restructured code, moved all modules into internal

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

internal/backends/spotify/client.go

@@ -0,0 +1,114 @@
+/*
+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 spotify
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"strconv"
+	"time"
+
+	"github.com/go-resty/resty/v2"
+	"golang.org/x/oauth2"
+)
+
+const baseURL = "https://api.spotify.com/v1/"
+const MaxItemsPerGet = 50
+const DefaultRateLimitWaitSeconds = 5
+
+type Client struct {
+	HttpClient *resty.Client
+}
+
+func NewClient(token oauth2.TokenSource) Client {
+	ctx := context.Background()
+	httpClient := oauth2.NewClient(ctx, token)
+	client := resty.NewWithClient(httpClient)
+	client.SetBaseURL(baseURL)
+	client.SetHeader("Accept", "application/json")
+	client.SetRetryCount(5)
+	client.AddRetryCondition(
+		func(r *resty.Response, err error) bool {
+			code := r.StatusCode()
+			return code == http.StatusTooManyRequests || code >= http.StatusInternalServerError
+		},
+	)
+	client.SetRetryMaxWaitTime(time.Duration(1 * time.Minute))
+	client.SetRetryAfter(func(client *resty.Client, resp *resty.Response) (time.Duration, error) {
+		var err error
+		var retryAfter int = DefaultRateLimitWaitSeconds
+		if resp.StatusCode() == http.StatusTooManyRequests {
+			retryAfter, err = strconv.Atoi(resp.Header().Get("Retry-After"))
+			if err != nil {
+				retryAfter = DefaultRateLimitWaitSeconds
+			}
+		}
+		return time.Duration(retryAfter * int(time.Second)), err
+	})
+	return Client{
+		HttpClient: client,
+	}
+}
+
+func (c Client) RecentlyPlayedAfter(after time.Time, limit int) (RecentlyPlayedResult, error) {
+	return c.recentlyPlayed(&after, nil, limit)
+}
+
+func (c Client) RecentlyPlayedBefore(before time.Time, limit int) (RecentlyPlayedResult, error) {
+	return c.recentlyPlayed(nil, &before, limit)
+}
+
+func (c Client) recentlyPlayed(after *time.Time, before *time.Time, limit int) (result RecentlyPlayedResult, err error) {
+	const path = "/me/player/recently-played"
+	request := c.HttpClient.R().
+		SetQueryParam("limit", strconv.Itoa(limit)).
+		SetResult(&result)
+	if after != nil {
+		request.SetQueryParam("after", strconv.FormatInt(after.Unix(), 10))
+	} else if before != nil {
+		request.SetQueryParam("before", strconv.FormatInt(before.Unix(), 10))
+	}
+	response, err := request.Get(path)
+
+	if response.StatusCode() != 200 {
+		err = errors.New(response.String())
+	}
+	return
+}
+
+func (c Client) UserTracks(offset int, limit int) (result TracksResult, err error) {
+	const path = "/me/tracks"
+	response, err := c.HttpClient.R().
+		SetQueryParams(map[string]string{
+			"offset": strconv.Itoa(offset),
+			"limit":  strconv.Itoa(limit),
+		}).
+		SetResult(&result).
+		Get(path)
+
+	if response.StatusCode() != 200 {
+		err = errors.New(response.String())
+	}
+	return
+}