use serde::de;
use serde::de::value::MapDeserializer;
use serde::forward_to_deserialize_any;
use std::collections::HashMap;
mod error;
use error::{Error, MpdResult};
mod structs;
pub use structs::Track;

/// some unprintable character to separate repeated keys
const SEPARATOR: char = '\x02';

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

impl<'de, Iter: Iterator<Item = (&'de str, &'de str)>> de::Deserializer<'de>
    for MPDeserializer<'de, Iter>
{
    type 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 deserialize_response<'a, I: Iterator<Item = &'a str>>(input: I) -> Result<Track, Error> {
    let mut map: HashMap<String, String> = HashMap::new();
    for line in input {
        if line.starts_with("OK") {
            break;
        } else if let Some(message) = line.strip_prefix("ACK") {
            return Err(Error::from_str(message.trim()));
        }
        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());
    // Eventually, I’d like to use my own deserializer instead of envy
    // 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());
    println!("{:?}", s);
}