#![allow(dead_code)]

// See https://support.google.com/podcast-publishers/answer/9889544
// for some reasonably guidelines for how a podcast RSS feed should look.

use std::fmt;
use std::borrow::Cow;

#[derive(Debug, serde::Deserialize)]
pub struct Feed<'a> {
    pub(crate) rss: Rss<'a>,
}

#[derive(Debug, serde::Deserialize)]
pub struct Rss<'a> {
    pub(crate) channel: Channel<'a>,
}

#[derive(Debug, serde::Deserialize)]
pub struct Channel<'a> {
    #[serde(rename = "item", default)]
    pub(crate) items: Vec<Item<'a>>,
    pub(crate) link: Option<Cow<'a, str>>,
    pub(crate) title: Cow<'a, str>,
    pub(crate) description: Option<Cow<'a, str>>,
    #[serde(rename = "{http://www.itunes.com/dtds/podcast-1.0.dtd}itunes:author")]
    pub(crate) author: Option<Cow<'a, str>>,
    #[serde(rename = "{http://www.itunes.com/dtds/podcast-1.0.dtd}itunes:summary")]
    pub(crate) summary: Option<Cow<'a, str>>,
    #[serde(rename = "{http://www.itunes.com/dtds/podcast-1.0.dtd}itunes:image")]
    pub(crate) itunes_image: Option<ItunesImage<'a>>,
    pub(crate) image: Option<Image<'a>>,
}

#[derive(Debug, serde::Deserialize)]
pub struct Image<'a> {
    pub(crate) link: Option<Cow<'a, str>>,
    pub(crate) title: Cow<'a, str>,
    pub(crate) url: Cow<'a, str>,
}

#[derive(Debug, serde::Deserialize)]
pub struct ItunesImage<'a> {
    #[serde(rename = "$attr:href")]
    pub(crate) href: Cow<'a, str>,
}

fn deserialize_publish_date<'de, D: serde::de::Deserializer<'de>> (
    deserializer: D
) -> Result<chrono::NaiveDateTime, D::Error> {
    struct Visitor;
    impl<'de> serde::de::Visitor<'de> for Visitor {
        type Value = chrono::NaiveDateTime;
    
        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
            formatter.write_str("a string containing json data")
        }
    
        fn visit_str<E: serde::de::Error>(self, input: &str) -> Result<Self::Value, E> {
            chrono::NaiveDateTime::parse_from_str(
                input,
                "%a, %d %b %Y %H:%M:%S %Z"
            ).map_err(E::custom)
        }
    }
    
    deserializer.deserialize_any(Visitor)
}

#[derive(Debug, serde::Deserialize)]
pub struct Item<'a> {
    pub(crate) title: Cow<'a, str>,
    pub(crate) enclosure: Option<Enclosure<'a>>,
    pub(crate) description: Option<Cow<'a, str>>,
    #[serde(rename = "{http://www.itunes.com/dtds/podcast-1.0.dtd}itunes:summary")]
    pub(crate) summary: Option<Cow<'a, str>>,
    #[serde(rename = "pubDate", deserialize_with = "deserialize_publish_date")]
    pub(crate) published: chrono::NaiveDateTime,
    pub(crate) guid: Option<Cow<'a, str>>,
}

#[derive(Debug, serde::Deserialize)]
pub struct Enclosure<'a> {
    #[serde(rename = "$attr:url")]
    pub(crate) url: Cow<'a, str>,
    #[serde(rename = "$attr:type")]
    pub(crate) mime_type: Option<Cow<'a, str>>,
    //#[serde(rename = "$attr:length")]
    //pub(crate) length: Option<u64>,
}