// Unit tests for the podcast fetcher's pure logic (plan task 1.4/1.10):
// RSS/iTunes/Podcasting-2.0 parsing, duration/pubDate spellings, slug/
// path layout, and the SSRF guard (scheme + resolved-IP checks). No DB.
package services

import (
	"errors"
	"net"
	"net/http"
	"net/http/httptest"
	"net/url"
	"strings"
	"testing"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5/pgtype"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

// pgUUID alias keeps the helper signatures short.
type pgUUID = pgtype.UUID

// Full-fixture feed covering the three namespaces and the fallback
// chains (itunes:title vs title; description vs itunes:summary vs
// content:encoded; itunes:author vs author vs dc:creator).
const podcastFixtureXML = `<?xml version="1.0" encoding="UTF-8"?>
<rss version="2.0"
     xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd"
     xmlns:content="http://purl.org/rss/1.0/modules/content/"
     xmlns:dc="http://purl.org/dc/elements/1.1/"
     xmlns:podcast="https://podcastindex.org/namespace/1.0">
  <channel>
    <title>The Test Feed</title>
    <link>https://example.com/show</link>
    <language>en-us</language>
    <description>&lt;p&gt;A feed about &lt;b&gt;testing&lt;/b&gt;.&lt;/p&gt;</description>
    <itunes:author>Host Name</itunes:author>
    <itunes:owner>
      <itunes:name>Owner Name</itunes:name>
      <itunes:email>owner@example.com</itunes:email>
    </itunes:owner>
    <itunes:image href="https://cdn.example.com/art.jpg"/>
    <itunes:explicit>false</itunes:explicit>
    <itunes:type>serial</itunes:type>
    <itunes:category text="Fiction">
      <itunes:category text="Drama"/>
    </itunes:category>
    <podcast:guid>9b0241c2-xxxx-4xxx-yxxx-xxxxxxxxxxxx</podcast:guid>
    <podcast:medium>audiobook</podcast:medium>
    <lastBuildDate>Mon, 26 Oct 2026 08:00:00 +0000</lastBuildDate>
    <item>
      <guid isPermaLink="false">episode-guid-1</guid>
      <itunes:title>Episode One: The Beginning</itunes:title>
      <title>Ep 1</title>
      <itunes:subtitle>First chapter</itunes:subtitle>
      <description><![CDATA[<p>Chapter one text.</p>]]></description>
      <itunes:author>Narrator A</itunes:author>
      <itunes:duration>1:02:03</itunes:duration>
      <itunes:episode>1</itunes:episode>
      <itunes:season>2</itunes:season>
      <pubDate>Sun, 25 Oct 2026 12:00:00 +0000</pubDate>
      <enclosure url="https://cdn.example.com/ep1.mp3" length="52428800" type="audio/mpeg"/>
      <podcast:transcript url="https://cdn.example.com/ep1.json" type="application/json"/>
      <podcast:chapters url="https://cdn.example.com/ep1-chapters.json" type="application/json+chapters"/>
      <podcast:person href="Narrator A" role="host"/>
      <podcast:person href="Guest B" role="guest"/>
    </item>
    <item>
      <guid>episode-guid-2</guid>
      <title>Episode Two</title>
      <itunes:summary>Summary only description.</itunes:summary>
      <dc:creator>Writer C</dc:creator>
      <itunes:duration>5400</itunes:duration>
      <pubDate>Mon, 26 Oct 2026 12:00:00 GMT</pubDate>
      <enclosure url="https://cdn.example.com/ep2.m4a" length="1048576" type="audio/mp4"/>
    </item>
  </channel>
</rss>`

func TestParsePodcastFeed(t *testing.T) {
	feed, err := ParsePodcastFeed([]byte(podcastFixtureXML))
	require.NoError(t, err)

	ch := feed.Channel
	assert.Equal(t, "The Test Feed", ch.Title)
	assert.Equal(t, "en-us", ch.Language)
	assert.Equal(t, "Host Name", ch.ITunesAuthor)
	assert.Equal(t, "Owner Name", ch.ITunesOwner.Name)
	assert.Equal(t, "owner@example.com", ch.ITunesOwner.Email)
	assert.Equal(t, "https://cdn.example.com/art.jpg", ch.ITunesImage.Href)
	assert.Equal(t, "serial", ch.ITunesType)
	assert.Equal(t, "Fiction", ch.ITunesCategory.Text)
	assert.Equal(t, "Drama", ch.ITunesCategory.Subcategory.Text)
	assert.Equal(t, "9b0241c2-xxxx-4xxx-yxxx-xxxxxxxxxxxx", ch.PodcastGUID)
	assert.Equal(t, "audiobook", ch.PodcastMedium)
	assert.False(t, parseExplicit(ch.ITunesExplicit))

	buildAt, ok := parseFeedTime(ch.LastBuildDate)
	require.True(t, ok)
	assert.Equal(t, 2026, buildAt.Year())

	require.Len(t, ch.Items, 2)

	// Item 1: itunes:title preferred, description chain, hosts/guests.
	it1 := &ch.Items[0]
	assert.Equal(t, "Episode One: The Beginning", it1.EpisodeTitle())
	assert.Equal(t, "First chapter", it1.Subtitle)
	assert.Equal(t, "<p>Chapter one text.</p>", it1.EpisodeDescription()) // raw HTML; stripping happens at storage time
	assert.Equal(t, "Narrator A", it1.EpisodeAuthor())
	assert.Equal(t, 3723, parseITunesDuration(it1.ITunesDuration)) // 1:02:03
	assert.Equal(t, 2, intMust(it1.ITunesSeason))
	assert.Equal(t, 1, intMust(it1.ITunesEpisode))
	assert.Equal(t, "https://cdn.example.com/ep1.mp3", it1.Enclosure.URL)
	assert.Equal(t, int64(52428800), it1.Enclosure.Length)
	assert.Equal(t, "audio/mpeg", it1.Enclosure.Type)
	assert.Equal(t, "https://cdn.example.com/ep1.json", it1.Transcript.URL)
	assert.Equal(t, "https://cdn.example.com/ep1-chapters.json", it1.Chapters.URL)
	hosts, guests := it1.HostsAndGuests()
	assert.Equal(t, []string{"Narrator A"}, hosts)
	assert.Equal(t, []string{"Guest B"}, guests)
	assert.Equal(t, "2026-10-25", mustDate(it1.PubDate))

	// Item 2: fallback chains — plain title, itunes:summary, dc:creator.
	it2 := &ch.Items[1]
	assert.Equal(t, "Episode Two", it2.EpisodeTitle())
	assert.Equal(t, "Summary only description.", it2.EpisodeDescription())
	assert.Equal(t, "Writer C", it2.EpisodeAuthor())
	assert.Equal(t, 5400, parseITunesDuration(it2.ITunesDuration)) // seconds
	assert.Equal(t, "https://cdn.example.com/ep2.m4a", it2.Enclosure.URL)
}

func intMust(s string) int {
	n, _ := parseSeasonOrEpisode(s)
	return n
}

func parseSeasonOrEpisode(s string) (int, bool) {
	if s == "" {
		return 0, false
	}
	n := 0
	for _, r := range s {
		if r < '0' || r > '9' {
			return 0, false
		}
		n = n*10 + int(r-'0')
	}
	return n, true
}

func mustDate(pubDate string) string {
	if t, ok := parseFeedTime(pubDate); ok {
		return t.UTC().Format("2006-01-02")
	}
	return ""
}

func TestParseITunesDuration(t *testing.T) {
	assert.Equal(t, 0, parseITunesDuration(""))
	assert.Equal(t, 90, parseITunesDuration("90"))
	assert.Equal(t, 3723, parseITunesDuration("1:02:03"))
	assert.Equal(t, 123, parseITunesDuration("2:03"))
	assert.Equal(t, 3600, parseITunesDuration("1 hour"))
	assert.Equal(t, 120, parseITunesDuration("2 minutes"))
	assert.Equal(t, 0, parseITunesDuration("soonish"))
}

func TestParseFeedTimeVariants(t *testing.T) {
	for _, tc := range []struct {
		in   string
		year int
	}{
		{"Mon, 26 Oct 2026 08:00:00 +0000", 2026},
		{"Mon, 26 Oct 2026 08:00:00 GMT", 2026},
		{"26 Oct 2026 08:00:00 +0000", 2026},
	} {
		tm, ok := parseFeedTime(tc.in)
		require.True(t, ok, "parse %q", tc.in)
		assert.Equal(t, tc.year, tm.Year())
	}
	_, ok := parseFeedTime("not a date")
	assert.False(t, ok)
}

func TestEpisodeExplicitSpellings(t *testing.T) {
	assert.True(t, parseExplicit("true"))
	assert.True(t, parseExplicit("yes"))
	assert.True(t, parseExplicit("explicit"))
	assert.False(t, parseExplicit("false"))
	assert.False(t, parseExplicit("clean"))
	assert.False(t, parseExplicit(""))
}

func TestSlugifyAndPaths(t *testing.T) {
	assert.Equal(t, "the-test-feed", slugify("The Test Feed!", 60))
	assert.Equal(t, "a-b-c", slugify("  A -- B // C  ", 60))
	assert.Equal(t, "abcdefghij", slugify("ABCDEFGHIJ", 10))

	slug := feedSlug("My Feed", testUUID("11111111-1111-1111-1111-111111111111"))
	assert.Equal(t, "my-feed-11111111", slug)

	rel := episodeRelPath(slug, 42, "Episode: The Test", ".mp3")
	assert.Equal(t, "my-feed-11111111/0042-episode-the-test.mp3", rel)

	assert.Equal(t, "my-feed-11111111/artwork.jpg", artworkRelPath(slug, ".jpg"))
}

func TestEnclosureExtension(t *testing.T) {
	assert.Equal(t, ".mp3", enclosureExtension("https://x.test/a/b/ep.mp3?token=1", ""))
	assert.Equal(t, ".m4a", enclosureExtension("https://x.test/ep", "audio/mp4"))
	assert.Equal(t, ".flac", enclosureExtension("https://x.test/ep", "audio/flac"))
	assert.Equal(t, ".mp3", enclosureExtension("https://x.test/ep", "weird/type"))
}

func TestStripHTML(t *testing.T) {
	assert.Equal(t, "hello world", stripHTML("<p>hello <b>world</b></p>"))
	assert.Equal(t, "a b", stripHTML("a\n\n  b"))
	assert.Equal(t, "", stripHTML(""))
}

func TestIsPublicIP(t *testing.T) {
	blocked := []string{
		"127.0.0.1", "10.0.0.5", "172.16.0.9", "192.168.1.1",
		"169.254.169.254", // cloud metadata endpoint
		"0.0.0.0", "::1", "fe80::1", "fd00::5", "::ffff:127.0.0.1",
		"::ffff:10.0.0.1", "224.0.0.1",
	}
	for _, s := range blocked {
		assert.False(t, isPublicIP(net.ParseIP(s)), "%s must be blocked", s)
	}
	allowed := []string{
		"93.184.216.34", "1.1.1.1", "2606:4700:4700::1111",
	}
	for _, s := range allowed {
		assert.True(t, isPublicIP(net.ParseIP(s)), "%s must be allowed", s)
	}
	assert.False(t, isPublicIP(nil))
}

func TestGuardURLScheme(t *testing.T) {
	u, _ := url.Parse("http://example.com/feed.xml")
	assert.Error(t, guardURLScheme(u))
	u, _ = url.Parse("ftp://example.com/feed.xml")
	assert.Error(t, guardURLScheme(u))
	u, _ = url.Parse("https://example.com/feed.xml")
	assert.NoError(t, guardURLScheme(u))
	assert.Error(t, guardURLScheme(nil))
}

// The REAL client (production factory) must refuse loopback targets —
// this is the SSRF boundary; httptest servers live on 127.0.0.1.
func TestGuardFetchBlocksLoopback(t *testing.T) {
	srv := newInsecureFeedServer(t, podcastFixtureXML)
	defer srv.Close()
	_, err := guardFetch(t.Context(), srv.URL, "", "", maxFeedSizeBytes)
	require.Error(t, err)
	assert.True(t, strings.Contains(err.Error(), "blocked") ||
		strings.Contains(err.Error(), "https"), "expected an SSRF/scheme rejection, got: %v", err)
}

func TestGuardFetchRejectsPlainHTTP(t *testing.T) {
	// A public-looking http:// URL: scheme guard fires before any dial.
	_, err := guardFetch(t.Context(), "http://example.com/feed.xml", "", "", maxFeedSizeBytes)
	require.Error(t, err)
	assert.Contains(t, err.Error(), "https")
}

func TestClassifyFetchError(t *testing.T) {
	err := classifyFetchError(ErrBlockedPrivateAddress)
	assert.Contains(t, err.Error(), "blocked")
	someErr := &url.Error{Op: "Get", Err: errors.New("boom")}
	assert.Equal(t, someErr.Error(), classifyFetchError(someErr).Error())
}

// testUUID builds a pgtype.UUID from a string (test helper).
func testUUID(s string) pgUUID {
	u, _ := uuid.Parse(s)
	return pgUUID{Bytes: u, Valid: true}
}

// newInsecureFeedServer serves body over httptest TLS (loopback) —
// used to prove the production client REFUSES it.
func newInsecureFeedServer(t *testing.T, body string) *httptest.Server {
	t.Helper()
	srv := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
		w.Header().Set("Content-Type", "application/rss+xml")
		_, _ = w.Write([]byte(body))
	}))
	t.Cleanup(srv.Close)
	return srv
}