import Foundation

struct AudioPlayerCommandProcessor: CommandProcessor {

    let commandType: ShorthandMarkdownKey = .audioPlayer

    let content: Content

    let results: PageGenerationResults

    init(content: Content, results: PageGenerationResults) {
        self.content = content
        self.results = results
    }

    func process(_ arguments: [String], markdown: Substring) -> String {
        guard arguments.count == 2 else {
            results.invalid(command: .audioPlayer, "Invalid audio player arguments")
            return ""
        }
        let fileId = arguments[0]
        let titleText = arguments[1]

        guard content.isValidIdForFile(fileId) else {
            results.invalid(command: .audioPlayer, "Invalid file id \(fileId) for audio player")
            return ""
        }

        guard let file = content.file(fileId) else {
            results.missingFiles.insert(fileId)
            return ""
        }
        let songs: [Song]
        do {
            let data = try file.dataContent()
            songs = try JSONDecoder().decode([Song].self, from: data)
        } catch {
            results.issues.insert(.failedToLoadContent(error))
            return ""
        }

        var playlist: [AudioPlayer.PlaylistItem] = []
        var amplitude: [AmplitudeSong] = []

        for song in songs {
            guard let image = content.image(song.cover) else {
                results.missing(file: song.cover, markdown: "Missing cover image \(song.cover) in \(file.id)")
                continue
            }

            guard let audioFile = content.file(song.file) else {
                results.missing(file: song.file, markdown: "Missing audio file \(song.file) in \(file.id)")
                continue
            }
            #warning("Check if file is audio")
            let coverUrl = image.absoluteUrl

            let playlistItem = AudioPlayer.PlaylistItem(
                index: playlist.count,
                image: coverUrl,
                name: song.name,
                album: song.album,
                track: song.track,
                artist: song.artist)

            let amplitudeSong = AmplitudeSong(
                name: song.name,
                artist: song.artist,
                album: song.album,
                track: "\(song.track)",
                url: audioFile.absoluteUrl,
                cover_art_url: coverUrl)

            playlist.append(playlistItem)
            amplitude.append(amplitudeSong)
        }

        let footerScript = AudioPlayerScript(items: amplitude).content
        results.requiredFooters.insert(footerScript)
        results.requiredHeaders.insert(.audioPlayerCss)
        results.requiredHeaders.insert(.audioPlayerJs)

        results.requiredIcons.formUnion([
            .audioPlayerClose,
            .audioPlayerPlaylist,
            .audioPlayerNext,
            .audioPlayerPrevious,
            .audioPlayerPlay,
            .audioPlayerPause
        ])

        return AudioPlayer(playingText: titleText, items: playlist).content
    }
}