From 0915ab09faef6c660fcf862ac3934711353568b4 Mon Sep 17 00:00:00 2001
From: Tordarus <tordarus@protonmail.com>
Date: Sun, 6 Feb 2022 10:39:04 +0100
Subject: [PATCH] context and cursor introduced

---
 airingschedule.go |  6 ++++--
 api.go            | 19 ++++++++++++++++---
 cursor.go         | 31 +++++++++++++++++++++++++++++++
 media.go          |  6 ++++--
 medialist.go      |  6 ++++--
 sub_selections.go |  3 +--
 types.go          |  1 -
 user.go           |  6 ++++--
 8 files changed, 64 insertions(+), 14 deletions(-)
 create mode 100644 cursor.go

diff --git a/airingschedule.go b/airingschedule.go
index 18984d9..e58f03c 100644
--- a/airingschedule.go
+++ b/airingschedule.go
@@ -1,8 +1,10 @@
 package anilist
 
-func (api *Api) GetAiringSchedule(vars AiringScheduleQuery, onError func(error)) <-chan *AiringSchedule {
+import "context"
+
+func (api *Api) GetAiringSchedule(ctx context.Context, vars AiringScheduleQuery, onError func(error)) Cursor[AiringSchedule] {
 	resp := responseObj[*page[AiringSchedule]]{}
-	return requestPaged(api, getAiringScheduleQuery, vars.toMap(), &resp, onError)
+	return requestPaged(api, ctx, getAiringScheduleQuery, vars.toMap(), &resp, onError)
 }
 
 const (
diff --git a/api.go b/api.go
index 144c1dd..89037b6 100644
--- a/api.go
+++ b/api.go
@@ -2,6 +2,7 @@ package anilist
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"net/http"
 )
@@ -60,15 +61,19 @@ func request[T any](api *Api, query string, vars map[string]interface{}, respObj
 	return nil
 }
 
-func requestPaged[R any](api *Api, query string, vars map[string]interface{}, respObj *responseObj[*page[R]], onError func(error)) <-chan *R {
+func requestPaged[R any](api *Api, ctx context.Context, query string, vars map[string]interface{}, respObj *responseObj[*page[R]], onError func(error)) Cursor[R] {
 	resp := responseObj[struct {
 		Page *page[R] `json:"Page"`
 	}]{}
 
+	var cancelFunc context.CancelFunc
+	ctx, cancelFunc = context.WithCancel(ctx)
+
 	out := make(chan *R, 50)
 
 	go func() {
 		defer close(out)
+		defer cancelFunc()
 
 		vars["page"] = 0
 
@@ -87,7 +92,11 @@ func requestPaged[R any](api *Api, query string, vars map[string]interface{}, re
 
 			for _, value := range resp.Data.Page.Data() {
 				value := value
-				out <- &value
+				select {
+				case out <- &value:
+				case <-ctx.Done():
+					return
+				}
 			}
 
 			if resp.Data.Page.PageInfo.CurrentPage == resp.Data.Page.PageInfo.LastPage {
@@ -96,5 +105,9 @@ func requestPaged[R any](api *Api, query string, vars map[string]interface{}, re
 		}
 	}()
 
-	return out
+	return Cursor[R]{
+		Chan:       out,
+		ctx:        ctx,
+		cancelFunc: cancelFunc,
+	}
 }
diff --git a/cursor.go b/cursor.go
new file mode 100644
index 0000000..4eccd7e
--- /dev/null
+++ b/cursor.go
@@ -0,0 +1,31 @@
+package anilist
+
+import "context"
+
+type Cursor[T any] struct {
+	ctx        context.Context
+	cancelFunc context.CancelFunc
+	Chan       <-chan *T
+}
+
+func (c Cursor[T]) First() *T {
+	defer c.cancelFunc()
+	return <-c.Chan
+}
+
+func (c Cursor[T]) Next() (*T, bool) {
+	if c.ctx.Err() == nil {
+		value, ok := <-c.Chan
+		return value, ok
+	}
+
+	return nil, false
+}
+
+func (c Cursor[T]) Slice() []T {
+	s := make([]T, 0)
+	for value, ok := c.Next(); ok; value, ok = c.Next() {
+		s = append(s, *value)
+	}
+	return s
+}
diff --git a/media.go b/media.go
index 918769e..e0d4911 100644
--- a/media.go
+++ b/media.go
@@ -1,8 +1,10 @@
 package anilist
 
-func (api *Api) GetMedia(vars MediaQuery, onError func(error)) <-chan *Media {
+import "context"
+
+func (api *Api) GetMedia(ctx context.Context, vars MediaQuery, onError func(error)) Cursor[Media] {
 	resp := responseObj[*page[Media]]{}
-	return requestPaged(api, getMediaQuery, vars.toMap(), &resp, onError)
+	return requestPaged(api, ctx, getMediaQuery, vars.toMap(), &resp, onError)
 }
 
 const (
diff --git a/medialist.go b/medialist.go
index 917dc95..e0547cb 100644
--- a/medialist.go
+++ b/medialist.go
@@ -1,8 +1,10 @@
 package anilist
 
-func (api *Api) GetMediaList(vars MediaListQuery, onError func(error)) <-chan *MediaList {
+import "context"
+
+func (api *Api) GetMediaList(ctx context.Context, vars MediaListQuery, onError func(error)) Cursor[MediaList] {
 	resp := responseObj[*page[MediaList]]{}
-	return requestPaged(api, getMediaListQuery, vars.toMap(), &resp, onError)
+	return requestPaged(api, ctx, getMediaListQuery, vars.toMap(), &resp, onError)
 }
 
 const (
diff --git a/sub_selections.go b/sub_selections.go
index 5e59ec7..fb5ac7f 100644
--- a/sub_selections.go
+++ b/sub_selections.go
@@ -7,7 +7,6 @@ const (
 		airingAt
 		timeUntilAiring
 		episode
-		media ` + subSelectionMedia + `
 	}`
 
 	subSelectionMediaList = `{
@@ -93,7 +92,7 @@ const (
 			isAdult
 			userId
 		}
-		nextAiringEpisode
+		nextAiringEpisode ` + subSelectionAiringSchedule + `
 	}`
 
 	subSelectionFuzzyDate = `{
diff --git a/types.go b/types.go
index 998a5e2..f41ac7e 100644
--- a/types.go
+++ b/types.go
@@ -211,5 +211,4 @@ type AiringSchedule struct {
 	AiringAt        UnixTime `json:"airingAt"`
 	TimeUntilAiring Seconds  `json:"timeUntilAiring"`
 	Episode         int      `json:"episode"`
-	Media           *Media   `json:"media"`
 }
diff --git a/user.go b/user.go
index f7b9903..10812cf 100644
--- a/user.go
+++ b/user.go
@@ -1,5 +1,7 @@
 package anilist
 
+import "context"
+
 func (api *Api) GetUserByName(name string) (*User, error) {
 	query := `query ($name: String) {
 		User (name: $name) ` + subSelectionUser + `
@@ -42,10 +44,10 @@ func (api *Api) GetUserByID(id int) (*User, error) {
 	return resp.Data.User, nil
 }
 
-func (api *Api) SearchUsers(search string, onError func(error)) <-chan *User {
+func (api *Api) SearchUsers(ctx context.Context, search string, onError func(error)) Cursor[User] {
 	vars := map[string]interface{}{"search": search}
 	resp := responseObj[*page[User]]{}
-	return requestPaged(api, searchUsersQuery, vars, &resp, onError)
+	return requestPaged(api, ctx, searchUsersQuery, vars, &resp, onError)
 }
 
 const (