use std::convert::TryFrom;
use std::io::BufReader;

use crate::DsnRespParseError;
use xml::attribute::OwnedAttribute;
use xml::reader::XmlEvent;
use xml::EventReader;

fn get_attr(attrs: &[OwnedAttribute], name: &str) -> Result<String, DsnRespParseError> {
    attrs
        .iter()
        .find_map(|o| {
            if o.name.local_name.eq(name) {
                Some(o.value.clone())
            } else {
                None
            }
        })
        .ok_or_else(|| DsnRespParseError::AttrMissing(name.to_string()))
}

#[derive(Clone, Debug)]
pub struct DsnResponse {
    pub stations: Vec<Station>,
}

impl DsnResponse {
    pub fn get_active_targets(&self) -> Vec<Target> {
        let mut targets = Vec::new();

        for station in &self.stations {
            for dish in &station.dishes {
                targets.append(&mut dish.target.clone())
            }
        }

        targets
    }

    pub fn from_xml_string(resp_str: &str) -> Result<DsnResponse, DsnRespParseError> {
        Self::from_xml_response(BufReader::new(resp_str.as_bytes()))
    }

    pub fn from_xml_response<T>(reader: BufReader<T>) -> Result<DsnResponse, DsnRespParseError>
    where
        T: std::io::Read,
    {
        let mut stations = Vec::new();

        let mut station: Option<Station> = None;
        let mut dish: Option<Dish> = None;

        let parser = EventReader::new(reader).into_iter();
        for e in parser {
            match e {
                Ok(XmlEvent::StartElement {
                    name, attributes, ..
                }) => {
                    if name.local_name.contains("station") {
                        if let Some(station) = station {
                            stations.push(station);
                        }
                        station = Some(Station::try_from(attributes).unwrap());
                    } else if name.local_name.contains("dish") {
                        dish = Some(Dish::try_from(attributes).unwrap());
                    } else if name.local_name.contains("downSignal") {
                        dish = Some(
                            dish.unwrap()
                                .add_down_signal(Signal::try_from(attributes).unwrap()),
                        );
                    } else if name.local_name.contains("upSignal") {
                        dish = Some(
                            dish.unwrap()
                                .add_up_signal(Signal::try_from(attributes).unwrap()),
                        );
                    } else if name.local_name.contains("target") {
                        dish = Some(
                            dish.unwrap()
                                .add_target(Target::try_from(attributes).unwrap()),
                        );
                    }
                }
                Ok(XmlEvent::EndElement { name }) => {
                    if name.local_name.contains("dish") && station.is_some() && dish.is_some() {
                        station = Some(station.unwrap().add_dish(dish.unwrap()));
                        dish = None;
                    }
                }
                Ok(XmlEvent::EndDocument) => {
                    if let Some(station) = station {
                        stations.push(station);
                        break;
                    }
                }
                Err(e) => {
                    return Err(DsnRespParseError::from(e));
                }
                _ => {}
            }
        }

        Ok(DsnResponse { stations })
    }
}

#[derive(Clone, Debug)]
pub struct Station {
    pub name: String,
    pub friendly_name: String,
    pub time_utc: u64,
    pub tz_offset: i64,
    pub dishes: Vec<Dish>,
}

impl Station {
    pub fn add_dish(mut self, dish: Dish) -> Self {
        self.dishes.push(dish);
        self
    }
}

impl TryFrom<Vec<OwnedAttribute>> for Station {
    type Error = DsnRespParseError;

    fn try_from(attrs: Vec<OwnedAttribute>) -> Result<Self, Self::Error> {
        let name = get_attr(&attrs, "name")?;
        let friendly_name = get_attr(&attrs, "friendlyName")?;
        let time_utc = get_attr(&attrs, "timeUTC")?.parse::<u64>()?;
        let tz_offset = get_attr(&attrs, "timeZoneOffset")?.parse::<i64>()?;

        Ok(Self {
            name,
            friendly_name,
            time_utc,
            tz_offset,
            dishes: Vec::new(),
        })
    }
}

#[derive(Clone, Debug, Eq, PartialEq)]
pub enum SignalType {
    Data,
    Carrier,
    None,
    Unkown(String),
}

impl From<String> for SignalType {
    fn from(s: String) -> Self {
        match s.to_lowercase().as_str() {
            "data" => SignalType::Data,
            "carrier" => SignalType::Carrier,
            "none" => SignalType::None,
            _ => SignalType::Unkown(s),
        }
    }
}

impl Default for SignalType {
    fn default() -> Self {
        SignalType::None
    }
}

#[derive(Clone, Debug, Default)]
pub struct Signal {
    pub signal_type: SignalType,
    pub data_rate: Option<f64>,
    pub frequency: Option<f64>,
    pub power: Option<f64>,
    pub spacecraft: String,
    pub spacecraft_id: Option<i32>,
}

impl TryFrom<Vec<OwnedAttribute>> for Signal {
    type Error = DsnRespParseError;

    fn try_from(attrs: Vec<OwnedAttribute>) -> Result<Self, Self::Error> {
        let signal_type = SignalType::from(get_attr(&attrs, "signalType")?);
        let data_rate = get_attr(&attrs, "dataRate")?.parse::<f64>().ok();
        let frequency = get_attr(&attrs, "frequency")?.parse::<f64>().ok();
        let power = get_attr(&attrs, "power")?.parse::<f64>().ok();
        let spacecraft = get_attr(&attrs, "spacecraft")?;
        let spacecraft_id = get_attr(&attrs, "spacecraftID")?.parse::<i32>().ok();

        Ok(Self {
            signal_type,
            data_rate,
            frequency,
            power,
            spacecraft,
            spacecraft_id,
        })
    }
}

#[derive(Clone, Debug, Default)]
pub struct Target {
    pub name: String,
    pub id: u32,
    /// Up Leg Range (km)
    pub upleg_range: f64,
    /// Down Leg Leg Range (km)
    pub downleg_range: f64,
    /// Round trip light time (s)
    pub rtlt: f64,
}

impl TryFrom<Vec<OwnedAttribute>> for Target {
    type Error = DsnRespParseError;

    fn try_from(attrs: Vec<OwnedAttribute>) -> Result<Self, Self::Error> {
        let name = get_attr(&attrs, "name")?;
        let id = get_attr(&attrs, "id")?.parse::<u32>()?;
        let upleg_range = get_attr(&attrs, "uplegRange")?.parse::<f64>()?;
        let downleg_range = get_attr(&attrs, "downlegRange")?.parse::<f64>()?;
        let rtlt = get_attr(&attrs, "rtlt")?.parse::<f64>()?;

        Ok(Self {
            name,
            id,
            upleg_range,
            downleg_range,
            rtlt,
        })
    }
}

#[derive(Clone, Debug)]
pub struct Dish {
    pub name: String,
    pub azimuth_angle: Option<f64>,
    pub elevation_angle: Option<f64>,
    pub wind_speed: Option<f64>,
    pub is_mspa: bool,
    pub is_array: bool,
    pub is_ddor: bool,
    pub up_signal: Vec<Signal>,
    pub down_signal: Vec<Signal>,
    pub target: Vec<Target>,
}

impl Dish {
    pub fn add_up_signal(mut self, signal: Signal) -> Self {
        self.up_signal.push(signal);
        self
    }

    pub fn add_down_signal(mut self, signal: Signal) -> Self {
        self.down_signal.push(signal);
        self
    }

    pub fn add_target(mut self, target: Target) -> Self {
        self.target.push(target);
        self
    }
}

impl TryFrom<Vec<OwnedAttribute>> for Dish {
    type Error = DsnRespParseError;

    fn try_from(attrs: Vec<OwnedAttribute>) -> Result<Self, Self::Error> {
        let name = get_attr(&attrs, "name")?;
        let azimuth_angle = get_attr(&attrs, "azimuthAngle")?.parse::<f64>().ok();
        let elevation_angle = get_attr(&attrs, "elevationAngle")?.parse::<f64>().ok();
        let wind_speed = get_attr(&attrs, "windSpeed")?.parse::<f64>().ok();
        let is_mspa = get_attr(&attrs, "isMSPA")?.parse::<bool>()?;
        let is_array = get_attr(&attrs, "isArray")?.parse::<bool>()?;
        let is_ddor = get_attr(&attrs, "isDDOR")?.parse::<bool>()?;

        Ok(Self {
            name,
            azimuth_angle,
            elevation_angle,
            wind_speed,
            is_mspa,
            is_array,
            is_ddor,
            up_signal: Vec::new(),
            down_signal: Vec::new(),
            target: Vec::new(),
        })
    }
}