use crate::{ProviderCommand, ProviderMessage};
use async_trait::async_trait;
use crabidy_core::{
    proto::crabidy::{LibraryNode, LibraryNodeChild, Track},
    ProviderClient, ProviderError,
};
use std::{fs, path::PathBuf, sync::Arc};
use tracing::{debug, debug_span, error, instrument, warn, Instrument};

#[derive(Debug)]
pub struct ProviderOrchestrator {
    pub provider_tx: flume::Sender<ProviderMessage>,
    provider_rx: flume::Receiver<ProviderMessage>,
    tidal_client: Arc<tidaldy::Client>,
}

impl ProviderOrchestrator {
    pub fn run(self) {
        tokio::spawn(async move {
            while let Ok(ProviderMessage { span, command }) = self.provider_rx.recv_async().await {
                let handler_span =
                    debug_span!(parent: &span, "provider_command", command = command.name());
                self.handle_command(command).instrument(handler_span).await;
            }
            warn!("provider message channel closed, loop exiting");
        });
    }

    async fn handle_command(&self, command: ProviderCommand) {
        match command {
            ProviderCommand::GetLibraryNode { path, result_tx } => {
                let result = self.get_lib_node(&path).await;
                if let Err(err) = result_tx.send_async(result).await {
                    error!("failed to send get_library_node result: {err}");
                }
            }
            ProviderCommand::GetTrackUrls { path, result_tx } => {
                let result = self.get_urls_for_track(&path).await;
                if let Err(err) = result_tx.send_async(result).await {
                    error!("failed to send get_track_urls result: {err}");
                }
            }
            ProviderCommand::ResolveTracks { path, result_tx } => {
                let result = self.resolve_tracks(&path).await;
                if let Err(err) = result_tx.send_async(result).await {
                    error!("failed to send resolve_tracks result: {err}");
                }
            }
        }
    }

    /// Resolves a path into playable tracks. A track path resolves to that
    /// single track; a node path is flattened by walking its queueable
    /// descendants.
    #[instrument(skip(self))]
    async fn resolve_tracks(&self, path: &str) -> Vec<Track> {
        if self.is_track_path(path) {
            return match self.get_metadata_for_track(path).await {
                Ok(track) => vec![track],
                Err(err) => {
                    warn!(path, "failed to resolve track: {err}");
                    Vec::new()
                }
            };
        }
        let mut tracks = Vec::new();
        let mut nodes_to_go = vec![path.to_string()];
        while let Some(node_path) = nodes_to_go.pop() {
            let node = match self.get_lib_node(&node_path).await {
                Ok(node) => node,
                Err(err) => {
                    warn!(node = node_path, "skipping unreadable node: {err}");
                    continue;
                }
            };
            if node.is_queable {
                tracks.extend(node.tracks);
                nodes_to_go.extend(node.children.into_iter().map(|c| c.path))
            }
        }
        debug!(count = tracks.len(), "resolved path into tracks");
        tracks
    }
}

#[async_trait]
impl ProviderClient for ProviderOrchestrator {
    #[instrument(skip(_s))]
    async fn init(_s: &str) -> Result<Self, ProviderError> {
        let config_dir = dirs::config_dir()
            .map(|d| d.join("crabidy"))
            .unwrap_or(PathBuf::from("/tmp"));
        let dir_exists = tokio::fs::try_exists(&config_dir)
            .await
            .map_err(|e| ProviderError::Config(e.to_string()))?;
        if !dir_exists {
            tokio::fs::create_dir(&config_dir)
                .await
                .map_err(|e| ProviderError::Config(e.to_string()))?;
        }
        let config_file = config_dir.join("tidaly.toml");
        debug!(config_file = %config_file.display(), "loading tidal config");
        let raw_toml_settings = fs::read_to_string(&config_file).unwrap_or_default();
        let tidal_client = Arc::new(tidaldy::Client::init(&raw_toml_settings).await.map_err(
            |err| {
                error!("failed to init tidal client: {err}");
                err
            },
        )?);
        let new_toml_config = tidal_client.settings();
        if let Err(err) = tokio::fs::write(&config_file, new_toml_config).await {
            error!("failed to write tidal config file: {err}");
        };
        let (provider_tx, provider_rx) = flume::bounded(100);
        Ok(Self {
            provider_rx,
            provider_tx,
            tidal_client,
        })
    }

    fn settings(&self) -> String {
        String::new()
    }

    /// Routes to the provider that owns the path.
    fn is_track_path(&self, path: &str) -> bool {
        if path == "/tidal" || path.starts_with("/tidal/") {
            return self.tidal_client.is_track_path(path);
        }
        false
    }

    #[instrument(skip(self))]
    async fn get_urls_for_track(&self, track_path: &str) -> Result<Vec<String>, ProviderError> {
        if track_path.starts_with("/tidal/") {
            return self.tidal_client.get_urls_for_track(track_path).await;
        }
        warn!(path = track_path, "no provider owns this track path");
        Err(ProviderError::MalformedPath)
    }

    #[instrument(skip(self))]
    async fn get_metadata_for_track(&self, track_path: &str) -> Result<Track, ProviderError> {
        if track_path.starts_with("/tidal/") {
            return self.tidal_client.get_metadata_for_track(track_path).await;
        }
        warn!(path = track_path, "no provider owns this track path");
        Err(ProviderError::MalformedPath)
    }

    fn get_lib_root(&self) -> LibraryNode {
        let mut root_node = LibraryNode::new();
        let child =
            LibraryNodeChild::new(tidaldy::PROVIDER_ROOT.to_owned(), "tidal".to_owned(), false);
        root_node.children.push(child);
        root_node
    }

    #[instrument(skip(self))]
    async fn get_lib_node(&self, path: &str) -> Result<LibraryNode, ProviderError> {
        if path == crabidy_core::ROOT_PATH {
            debug!("serving global library root");
            return Ok(self.get_lib_root());
        }
        if path == tidaldy::PROVIDER_ROOT || path.starts_with("/tidal/") {
            return self.tidal_client.get_lib_node(path).await;
        }
        warn!(path, "no provider owns this path");
        Err(ProviderError::MalformedPath)
    }
}