package model

import (
	"context"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
)

func TestLoadFeed_Success(t *testing.T) {
	// Mock RSS feed
	rssFeed := `
		<rss version="2.0">
			<channel>
				<title>Test Podcast</title>
				<description>This is a test podcast</description>
				<link>http://example.com</link>
				<image>
					<url>http://example.com/image.jpg</url>
				</image>
				<copyright>Test Copyright</copyright>
				<language>en</language>
				<item>
					<title>Episode 1</title>
					<link>http://example.com/episode1</link>
					<description>Episode 1 description</description>
				</item>
			</channel>
		</rss>
	`

	// Create a test server
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte(rssFeed))
	}))
	defer server.Close()

	// Call LoadFeed
	podcast, err := LoadFeed(server.URL, "", 10*time.Second)

	// Assertions
	assert.NoError(t, err)
	assert.NotNil(t, podcast)
	assert.Equal(t, "Test Podcast", podcast.Title)
	assert.Equal(t, "This is a test podcast", podcast.Description)
	assert.Equal(t, "http://example.com", podcast.Link)
	assert.Equal(t, "http://example.com/image.jpg", podcast.Image)
	assert.Equal(t, "Test Copyright", podcast.Copyright)
	assert.Equal(t, "en", podcast.Language)
	assert.Len(t, podcast.Episodes, 1)
	assert.Equal(t, "Episode 1", podcast.Episodes[0].Title)
}

func TestLoadFeed_Timeout(t *testing.T) {
	// Create a test server that delays response
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		time.Sleep(2 * time.Second)
		w.Write([]byte("<rss></rss>"))
	}))
	defer server.Close()

	// Call LoadFeed with a short timeout
	_, err := LoadFeed(server.URL, "", 1*time.Second)

	// Assertions
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "context deadline exceeded")
}

func TestLoadFeed_InvalidURL(t *testing.T) {
	// Call LoadFeed with an invalid URL
	_, err := LoadFeed("http://invalid-url", "", 10*time.Second)

	// Assertions
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "解析播客订阅失败")
}

func TestLoadFeed_EmptyFeed(t *testing.T) {
	// Create a test server with an empty feed
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte(""))
	}))
	defer server.Close()

	// Call LoadFeed
	_, err := LoadFeed(server.URL, "", 10*time.Second)

	// Assertions
	assert.Error(t, err)
	assert.Contains(t, err.Error(), "解析播客订阅失败")
}

// UA 是这个库唯一会影响「能不能抓到」的可配项：实测有源站按 UA 黑名单直接 403
// （feed.xyzfm.space 对 gofeed 出厂的 "Gofeed/1.0" 返回 denied by UA ACL = blacklist），
// 且无 UA 的请求比任何 UA 都更容易被拒。故这三条都必须钉死在测试里。
func TestLoadFeedWithOptions_UserAgent(t *testing.T) {
	cases := []struct {
		name string
		give string
		want string
	}{
		{"显式指定的 UA 逐字节发出", "txpodcast/1.0", "txpodcast/1.0"},
		{"空串回落默认而不是发空头", "", DefaultUserAgent},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			t.Parallel()
			// buffered chan 而非裸变量：handler 在另一个 goroutine 里写，-race 会告警。
			got := make(chan string, 1)
			srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
				got <- r.Header.Get("User-Agent")
				_, _ = w.Write([]byte(`<rss version="2.0"><channel><title>t</title></channel></rss>`))
			}))
			defer srv.Close()

			_, err := LoadFeedWithOptions(context.Background(), srv.URL,
				FeedOptions{UserAgent: tc.give, Timeout: 10 * time.Second})
			assert.NoError(t, err)
			assert.Equal(t, tc.want, <-got)
		})
	}
}

// 旧签名必须继续发默认 UA：它是 LoadFeedWithOptions 的包装，委托时若漏传就会退化成空头。
func TestLoadFeedContext_KeepsDefaultUserAgent(t *testing.T) {
	got := make(chan string, 1)
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		got <- r.Header.Get("User-Agent")
		_, _ = w.Write([]byte(`<rss version="2.0"><channel><title>t</title></channel></rss>`))
	}))
	defer srv.Close()

	_, err := LoadFeedContext(context.Background(), srv.URL, "", 10*time.Second)
	assert.NoError(t, err)
	assert.Equal(t, DefaultUserAgent, <-got)
}

// timeout <= 0 回落 30 秒的既有语义不能因为改走 FeedOptions 而丢失。
func TestLoadFeedWithOptions_ZeroTimeoutFallsBack(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_, _ = w.Write([]byte(`<rss version="2.0"><channel><title>t</title></channel></rss>`))
	}))
	defer srv.Close()

	// 0 若被原样当成超时，请求会立刻 context deadline exceeded。
	_, err := LoadFeedWithOptions(context.Background(), srv.URL, FeedOptions{})
	assert.NoError(t, err)
}