use serde::de;
use serde::de::value::MapDeserializer;
use serde::forward_to_deserialize_any;
use serde::Deserialize;
use std::fmt;
use std::time::Duration;
mod error;
use error::MpdResult;

struct MPDeserializer<'de, Iter: Iterator<Item = (&'de str, &'de str)>> {
    inner: MapDeserializer<'de, Iter, error::Error>,
}

/// Deserialize time from an integer that represents the seconds.
/// mpd uses int for the database stats (e.g. total time played).
fn de_time_int<'de, D>(deserializer: D) -> Result<Duration, D::Error>
where
    D: de::Deserializer<'de>,
{
    u64::deserialize(deserializer).map(Duration::from_secs)
}

/// Deserialize time from a float that represents the seconds.
/// mpd uses floats for the current status (e.g. time elapsed in song).
fn de_time_float<'de, D>(deserializer: D) -> Result<Option<Duration>, D::Error>
where
    D: de::Deserializer<'de>,
{
    f64::deserialize(deserializer)
        .map(Duration::from_secs_f64)
        .map(Some)
}

/// mpd uses bints (0 or 1) to represent booleans,
/// so we need a special parser for those.
fn de_bint<'de, D>(deserializer: D) -> Result<bool, D::Error>
where
    D: de::Deserializer<'de>,
{
    match u8::deserialize(deserializer)? {
        0 => Ok(false),
        1 => Ok(true),
        n => Err(de::Error::invalid_value(
            de::Unexpected::Unsigned(n as u64),
            &"zero or one",
        )),
    }
}

#[derive(Deserialize, Clone, Debug)]
pub struct Track {
    pub file: String,
    pub artist_sort: Option<String>,
    pub album_artist: Option<String>,
    pub album_sort: Option<String>,
    pub album_artist_sort: Option<String>,
    #[serde(deserialize_with = "string_or_vec")]
    #[serde(default)]
    #[serde(rename = "performer")]
    pub performers: Vec<String>,
    pub genre: Option<String>,
    pub title: Option<String>,
    pub track: Option<u32>,
    pub album: Option<String>,
    pub artist: Option<String>,
    pub pos: Option<u32>,
    pub id: Option<u32>,
    // TODO: use proper time here
    pub last_modified: Option<String>,
    pub original_date: Option<String>,
    pub time: Option<String>,
    pub format: Option<String>,
    #[serde(deserialize_with = "de_time_float")]
    pub duration: Option<Duration>,
    pub label: Option<String>,
    pub date: Option<String>,
    pub disc: Option<u32>,
    pub musicbraiz_trackid: Option<String>,
    pub musicbrainz_albumid: Option<String>,
    pub musicbrainz_albumartistid: Option<String>,
    pub musicbrainz_artistid: Option<String>,
    pub musicbraiz_releasetrackid: Option<String>,
    pub composer: Option<String>,
}

// some unprintable character
const SEPARATOR: char = '\x02';

impl<'de, Iter: Iterator<Item = (&'de str, &'de str)>> de::Deserializer<'de>
    for MPDeserializer<'de, Iter>
{
    type Error = error::Error;

    fn deserialize_any<V>(self, visitor: V) -> MpdResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        self.deserialize_map(visitor)
    }

    fn deserialize_map<V>(self, visitor: V) -> MpdResult<V::Value>
    where
        V: de::Visitor<'de>,
    {
        visitor.visit_map(self.inner)
    }

    forward_to_deserialize_any! {
        bool char str string bytes byte_buf unit unit_struct seq
        tuple tuple_struct struct identifier ignored_any
        i8 i16 i32 i64 i128 u8 u16 u32 u64 u128 f32 f64 option newtype_struct enum
    }
}

fn string_or_vec<'de, D>(deserializer: D) -> Result<Vec<String>, D::Error>
where
    D: de::Deserializer<'de>,
{
    struct StringOrVec();

    impl<'de> de::Visitor<'de> for StringOrVec {
        type Value = Vec<String>;

        fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
            formatter.write_str("string or list of strings")
        }

        fn visit_str<E: de::Error>(self, value: &str) -> Result<Self::Value, E> {
            Ok(value
                .split(SEPARATOR)
                .map(std::string::String::from)
                .collect())
        }
    }

    deserializer.deserialize_any(StringOrVec())
}

fn deserialize_response<'a, I: Iterator<Item = &'a str>>(input: I) -> Result<Track, error::Error> {
    let mut map: std::collections::HashMap<String, String> = std::collections::HashMap::new();
    for line in input {
        if let Some(_) = line.strip_prefix("OK") {
            break;
        } else if let Some(message) = line.strip_prefix("ACK") {
            return Err(error::Error {
                message: message.trim().to_string(),
            });
        }
        let mut fields = line.splitn(2, ": ");
        match (fields.next(), fields.next()) {
            (Some(k), Some(v)) => {
                if let Some(existing) = map.get_mut(k) {
                    existing.push(SEPARATOR);
                    existing.push_str(v);
                } else {
                    map.insert(k.to_string(), v.to_string());
                }
            }
            _ => panic!("invalid response line: {:?}", line),
        }
    }
    return Ok(envy::from_iter(map).unwrap());
    // let deser = MPDeserializer {
    // inner: MapDeserializer::new(map.into_iter()),
    // };
    // Song::deserialize(deser)
}

fn main() {
let input_str = "file: Youtube Rip/VVVVVV Medley.flac
Last-Modified: 2018-03-07T13:18:01Z
Album: VVVVVV OST / PPPPPP
Artist: FamilyJules7x
Composer: Magnus Pålsson
Date: 2014
Genre: Video Game Music
Title: VVVVVV Medley
Time: 433
duration: 432.727
Pos: 1548
Id: 1549";
    let s = deserialize_response(input_str.lines());
    dbg!(s);
}