feat: support bilibili fetch for festival

[Ovler-Young]

如 https://www.bilibili.com/festival/VSF2026live?bvid=BV1zAFrzaEQz 的这些有B站主题页的视频中可能没有playinfo，故尝试使用API进行获取。
close #25

[Copilot]

Pull request overview

This pull request adds fallback support for fetching Bilibili festival videos that don't have window.__playinfo__ embedded in the HTML. When the regex extraction of playinfo fails, the code now falls back to making API calls to Bilibili's web-interface and player endpoints to retrieve video metadata and streaming URLs.

Changes:

• Added API-based fallback for fetching Bilibili video metadata when HTML regex extraction fails
• Introduced two new response structures (BilibiliWebInterfaceView and BilibiliPlayUrlResponse) to handle API responses
• Implemented fetchBytesFromApi() function to fetch video data using Bilibili's public APIs

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 7 comments.

File	Description
processor/bilibili/fetch_media_entity.go	Added two new struct types for API response parsing: BilibiliWebInterfaceView for metadata and BilibiliPlayUrlResponse for playback URLs
processor/bilibili/bilibili.go	Modified FetchMetaAndResourceInfo to fall back to API calls on regex failure; added fetchBytesFromApi function implementing the API-based retrieval logic

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[Copilot]

Duplicate comment "audio resource" appears on consecutive lines. Remove one of the duplicate comments.

Suggested change

// audio resource

[Copilot]

Duplicate field "Codecid" appears twice in the same struct (lines 113 and 124). The second occurrence on line 124 is named "Codecid2" but has the same JSON tag "codecid". This will cause JSON unmarshaling to use only the first field, making the second field unreachable. Consider removing the duplicate field or using a different JSON tag if both fields are needed.

[Copilot]

Duplicate field "Codecid" appears twice in the same struct (lines 132 and 143). The second occurrence on line 143 is named "Codecid2" but has the same JSON tag "codecid". This will cause JSON unmarshaling to use only the first field, making the second field unreachable. Consider removing the duplicate field or using a different JSON tag if both fields are needed.

[Copilot]

Duplicate field "Codecid" appears twice in the same struct (lines 153 and 164). The second occurrence on line 164 is named "Codecid2" but has the same JSON tag "codecid". This will cause JSON unmarshaling to use only the first field, making the second field unreachable. Consider removing the duplicate field or using a different JSON tag if both fields are needed.

[Copilot]

The inline anonymous struct type for bestAudio (lines 171-189) duplicates the Audio struct definition from BilibiliPlayUrlResponse.Data.Dash.Audio (lines 126-144). Consider extracting this as a named type to avoid duplication and improve maintainability. For example, create a DashAudioItem type that can be reused in both places.

[Copilot]

There's no handling for the case when playData.Data.Dash.Audio is empty. If no audio streams are available, the function will return a MediaMeta with an empty Audios slice and only video streams. Consider checking if the Audio slice is empty and either returning an error similar to the original implementation (line 76: "no audio data") or documenting that this is intentional for festival videos that may only have video streams.

Suggested change

	if bestAudio != nil {
	mediaMeta.Audios = append(mediaMeta.Audios, meta.Audio{
	Url: bestAudio.BaseUrl,
	BitRate: bestAudio.Bandwidth / 1000,
	})
	}
	if bestAudio == nil {
	return meta.MediaMeta{}, errors.New("no audio data")
	}
	mediaMeta.Audios = append(mediaMeta.Audios, meta.Audio{
	Url: bestAudio.BaseUrl,
	BitRate: bestAudio.Bandwidth / 1000,
	})

[Copilot]

The artist extraction logic (lines 160-168) duplicates the same logic in the getSinger function (lines 238-254). Consider refactoring to reuse the getSinger function, or create a shared function that works with both AudioMeta and BilibiliWebInterfaceView structures. This would improve maintainability and ensure consistent behavior.

Suggested change

	if len(metaData.Data.Staff) == 0 {
	mediaMeta.Artist = metaData.Data.Owner.Name
	} else {
	var names []string
	for _, staff := range metaData.Data.Staff {
	names = append(names, staff.Name)
	}
	mediaMeta.Artist = strings.Join(names, ", ")
	}
	mediaMeta.Artist = getSinger(metaData.Data)