extern crate serde_json;

use serde_json::Value;
use std::collections::{BTreeMap, BTreeSet, HashSet};
use std::fmt;
use std::fs::File;
use std::io::{BufRead, BufReader, Error};

/// Observation message number.
const MSG_OBS: u64 = 74;

/// GPS ephemeris message number.
const MSG_EPHEMERIS_GPS: u64 = 138;

/// Galileo ephemeris message number.
const MSG_EPHEMERIS_GAL: u64 = 149;

/// SSR combined orbit and clock message number.
const MSG_SSR_ORBIT_CLOCK: u64 = 1501;

/// SSR code bias message number.
const MSG_SSR_CODE_BIASES: u64 = 1505;

/// SSR phase bias message number.
const MSG_SSR_PHASE_BIASES: u64 = 1510;

/// GPS signal codes.
const GPS_CODES: [u64; 12] = [0, 1, 5, 6, 7, 8, 9, 10, 11, 56, 57, 58];

/// Galileo signal codes.
const GAL_CODES: [u64; 16] = [
    14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 61,
];

/// Signal identifier with optional issue of data.
#[derive(Ord, PartialOrd, Eq, PartialEq, Clone, Debug)]
struct Sid {
    sat: u64,
    code: u64,
    iod: Option<u64>,
}

impl fmt::Display for Sid {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        if let Some(iod) = self.iod {
            write!(fmt, "{}:{}-{}", self.sat, self.code, iod)
        } else {
            write!(fmt, "{}:{}", self.sat, self.code)
        }
    }
}

/// Message information to dump.
#[derive(Debug)]
struct Msg {
    msg_type: u64,
    sender: u64,
    tow: u64,
    sid_set: BTreeSet<Sid>,
}

impl Msg {
    /// Build message from all GPS and Galileo observations.
    fn observations(value: &Value, msg_type: u64, sender: u64) -> Option<Msg> {
        value["header"]["t"]["tow"].as_u64().and_then(|tow| {
            value["obs"].as_array().and_then(|obs| {
                let mut sid_set: BTreeSet<Sid> = BTreeSet::new();
                for ob in obs.iter() {
                    if let Some(sat) = ob["sid"]["sat"].as_u64() {
                        if let Some(code) = ob["sid"]["code"].as_u64() {
                            sid_set.insert(Sid {
                                sat,
                                code,
                                iod: None,
                            });
                        }
                    }
                }
                Some(Msg {
                    msg_type,
                    sender,
                    tow: tow / 1000,
                    sid_set,
                })
            })
        })
    }

    /// Build message from GPS and Galileo ephemerides.
    fn ephemerides(value: &Value, msg_type: u64, sender: u64) -> Option<Msg> {
        value["common"]["toe"]["tow"].as_u64().and_then(|tow| {
            value["common"]["sid"]["sat"].as_u64().and_then(|sat| {
                value["common"]["sid"]["code"].as_u64().and_then(|code| {
                    let mut sid_set: BTreeSet<Sid> = BTreeSet::new();
                    sid_set.insert(Sid {
                        sat,
                        code,
                        iod: value["iode"].as_u64(),
                    });
                    Some(Msg {
                        msg_type,
                        sender,
                        tow,
                        sid_set,
                    })
                })
            })
        })
    }

    /// Build message from GPS and Galileo SSR corrections.
    fn corrections(value: &Value, msg_type: u64, sender: u64) -> Option<Msg> {
        value["time"]["tow"].as_u64().and_then(|tow| {
            value["sid"]["sat"].as_u64().and_then(|sat| {
                value["sid"]["code"].as_u64().and_then(|code| {
                    let mut sid_set: BTreeSet<Sid> = BTreeSet::new();
                    sid_set.insert(Sid {
                        sat,
                        code,
                        iod: value["iod"].as_u64(),
                    });
                    Some(Msg {
                        msg_type,
                        sender,
                        tow,
                        sid_set,
                    })
                })
            })
        })
    }

    /// Build message.
    fn new(value: &Value) -> Option<Msg> {
        value["msg_type"].as_u64().and_then(|msg_type| {
            value["sender"].as_u64().and_then(|sender| match msg_type {
                MSG_OBS => Self::observations(value, msg_type, sender),
                MSG_EPHEMERIS_GPS => Self::ephemerides(value, msg_type, sender),
                MSG_EPHEMERIS_GAL => Self::ephemerides(value, msg_type, sender),
                MSG_SSR_ORBIT_CLOCK => Self::corrections(value, msg_type, sender),
                MSG_SSR_CODE_BIASES => Self::corrections(value, msg_type, sender),
                MSG_SSR_PHASE_BIASES => Self::corrections(value, msg_type, sender),
                _ => None,
            })
        })
    }
}

/// Dump messages from file.
pub fn dump(file: &File, matched: bool, gps: bool, gal: bool) -> Result<(), Error> {
    let buf = BufReader::new(file);

    let mut code_set: HashSet<u64> = HashSet::new();
    if gps {
        for code in GPS_CODES.iter() {
            code_set.insert(*code);
        }
    }
    if gal {
        for code in GAL_CODES.iter() {
            code_set.insert(*code);
        }
    }

    if matched {
        let mut tow_map: BTreeMap<u64, BTreeMap<u64, BTreeMap<u64, BTreeSet<Sid>>>> =
            BTreeMap::new();
        for line in buf.lines() {
            let value: Value = serde_json::from_str(&(line?))?;
            if let Some(msg) = Msg::new(&value) {
                let mut sid_set = msg.sid_set;
                tow_map
                    .entry(msg.tow)
                    .or_insert_with(BTreeMap::new)
                    .entry(msg.sender)
                    .or_insert_with(BTreeMap::new)
                    .entry(msg.msg_type)
                    .or_insert_with(BTreeSet::new)
                    .append(&mut sid_set);
            }
        }

        for (tow, sender_map) in tow_map.iter() {
            for (sender, msg_type_map) in sender_map.iter() {
                for (msg_type, sid_set) in msg_type_map.iter() {
                    let mut sid_set_str = String::new();
                    for sid in sid_set.iter() {
                        if code_set.contains(&sid.code) {
                            sid_set_str.push_str(&format!("{} ", sid));
                        }
                    }
                    println!("{:>6} {:>5} {:>4} {}", tow, sender, msg_type, sid_set_str);
                }
            }
            println!();
        }
    } else {
        for line in buf.lines() {
            let value: Value = serde_json::from_str(&(line?))?;
            if let Some(msg) = Msg::new(&value) {
                let mut sid_set_str = String::new();
                for sid in msg.sid_set.iter() {
                    if code_set.contains(&sid.code) {
                        sid_set_str.push_str(&format!("{} ", sid));
                    }
                }
                println!(
                    "{:>6} {:>5} {:>4} {}",
                    msg.tow, msg.sender, msg.msg_type, sid_set_str
                );
            }
        }
    }

    Ok(())
}