use std::path;
use std::collections::BTreeMap;

#[derive(clap::Parser)]
pub(crate) struct Args {
    /// Path to the configuration file listing podcast RSS feeds.
    #[arg(default_value = "./podcasts.toml")]
    pub(crate) config: path::PathBuf,
    #[command(subcommand)]
    pub(crate) command: Command,
}

#[derive(clap::ValueEnum, Copy, Clone, Debug,PartialEq, Eq, PartialOrd, Ord)]
pub(crate) enum ListenStatus {
    Listened,
    Unlistened,
}

#[derive(clap::Subcommand)]
pub(crate) enum Command {
    /// Updates feed and downloads latest episodes.
    Download {
        /// The podcast to update. Updates all in configuration file if unspecified.
        #[arg(long, short)]
        podcast: Option<String>,
    },
    /// Lists the episodes for a given podcast, filtered based on if it has been listened or not.
    List {
        /// Filter for if episodes have been listened to or not.
        #[arg(long, short)]
        status: Option<ListenStatus>,
        /// The podcast to list episodes for.
        #[arg(long, short)]
        podcast: String,
    },
    /// Marks an entire podcast's history of episodes as played or unplayed.
    Mark {
        /// The new listen status for the episodes.
        #[arg(long, short)]
        status: ListenStatus,
        /// The podcast to change the listen status of.
        #[arg(long, short)]
        podcast: String,
    },
    /// Generates playlist for use with an iPod.
    Playlist {
        /// The podcast to generate the playlist for.
        #[arg(long, short)]
        podcast: Option<String>,
    },
    /// Syncs local copy of podcasts to Rockbox iPod.
    Sync {
        /// Directory to the root of the iPod running Rockbox.
        ipod_dir: path::PathBuf,
        /// Download any new episodes before syncing.
        #[clap(short, long)]
        download: bool,
    },
}

/// Struct modelling configuration file format.
#[derive(serde::Deserialize)]
pub(crate) struct Config {
    /// Map from podcast alias to RSS feed either as a url (prefix: http) or file path.
    pub(crate) podcasts: BTreeMap<String, Source>,
}

#[derive(serde::Deserialize)]
#[serde(untagged)]
pub(crate) enum Source {
    String(String),
    Object {
        source: String,
        #[serde(rename = "skip-download")]
        skip_download: bool,
    },
}

impl Source {
    pub(crate) fn source_raw(&self) -> &str {
        match self {
            Self::String(source) | Self::Object { source, .. } => source,
        }
    }

    pub(crate) fn skip_download(&self) -> bool {
        match self {
            Self::String(_) => false,
            Self::Object { skip_download, .. } => *skip_download,
        }
    }

    fn is_url(&self) -> bool {
        self.source_raw().starts_with("http")
    }

    pub(crate) fn source(&self) -> SourceKind<'_> {
        if self.is_url() {
            SourceKind::Url(self.source_raw())
        } else {
            SourceKind::Path(self.source_raw())
        }
    }
}

pub(crate) enum SourceKind<'a> {
    Url(&'a str),
    Path(&'a str),
}