use std::path::Path;

use lofty::file::TaggedFileExt;
use lofty::tag::{ItemKey, ItemValue};

/// A single key-value metadata item from a tag.
pub struct TagEntry {
    pub key: String,
    pub value: String,
}

/// Read all metadata items from a music file.
/// Returns `None` if no tags are present, otherwise a list of all tag entries.
pub fn read_all_metadata(path: &Path) -> Result<Option<Vec<TagEntry>>, lofty::error::LoftyError> {
    let tagged_file = lofty::read_from_path(path)?;

    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
        return Ok(None);
    };

    let entries = tag
        .items()
        .filter_map(|item| {
            let value = match item.value() {
                ItemValue::Text(t) | ItemValue::Locator(t) => t.clone(),
                ItemValue::Binary(b) => format!("<{} bytes>", b.len()),
            };
            Some(TagEntry {
                key: format!("{:?}", item.key()),
                value,
            })
        })
        .collect();

    Ok(Some(entries))
}

/// Extract the artist name from a music file.
pub fn read_artist_name(path: &Path) -> Result<Option<String>, lofty::error::LoftyError> {
    let tagged_file = lofty::read_from_path(path)?;

    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
        return Ok(None);
    };

    Ok(tag.get_string(ItemKey::TrackArtist).map(String::from))
}

/// Extract the MusicBrainz artist ID from a music file.
pub fn read_artist_mbid(path: &Path) -> Result<Option<String>, lofty::error::LoftyError> {
    let tagged_file = lofty::read_from_path(path)?;

    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
        return Ok(None);
    };

    Ok(tag.get_string(ItemKey::MusicBrainzArtistId).map(String::from))
}

/// Extract the MusicBrainz recording ID from a music file.
pub fn read_track_mbid(path: &Path) -> Result<Option<String>, lofty::error::LoftyError> {
    let tagged_file = lofty::read_from_path(path)?;

    let Some(tag) = tagged_file.primary_tag().or_else(|| tagged_file.first_tag()) else {
        return Ok(None);
    };

    Ok(tag.get_string(ItemKey::MusicBrainzRecordingId).map(String::from))
}