use reqwest::blocking::get;
use serde_derive::{Deserialize, Serialize};
use std::{fs, process::exit, thread::{sleep}};
use chrono::{Utc, Duration, Date};
mod cloudflare;

fn default_key() -> String {
    return "".to_string();
}

struct ChangeTracker {
    created: u16,
    updated: u16,
    unchanged: u16,
    error: u16
}

impl ChangeTracker {
    fn new() -> ChangeTracker {
        ChangeTracker { 
            created: 0, 
            updated: 0, 
            unchanged: 0, 
            error: 0 
        }
    }

    fn print(&self, f: &str) {
        match f {
            "" => {
                self.print("simple");
            }
            "simple" => {
                println!("{} created", self.created);
                println!("{} updated", self.updated);
                println!("{} unchanged", self.unchanged);
                println!("{} errors", self.error);
            }
            &_ => {
                println!("unknown format pattern '{}', defaulting to 'simple'", f);
                self.print("simple");
            }
        }
    }
}

#[derive(Serialize, Deserialize)]
struct DnsEntry {
    name: String,
    type4: bool,
    type6: bool,
    interface: Option<String>,
}

#[derive(Serialize, Deserialize)]
struct DnsZone {
    email: String,
    name: String,
    id: String,
    dns_entries: Vec<DnsEntry>,
}

#[derive(Serialize, Deserialize)]
struct DnsConfig {
    ipv6_interface: String,
    #[serde(default = "default_key")]
    api_key: String,
    zones: Vec<DnsZone>,
}

impl DnsConfig {
    fn new() -> DnsConfig {
        DnsConfig {
            ipv6_interface: "".to_string(),
            api_key: "".to_string(),
            zones: Vec::new(),
        }
    }

    fn load(&mut self) {
        let file_contents = match fs::read_to_string("config.json") {
            Ok(data) => data,
            Err(e) => panic!("{:#?}", e),
        };
        let config_parse: DnsConfig = match serde_json::from_str(&file_contents) {
            Ok(data) => data,
            Err(e) => panic!("{:#?}", e),
        };

        let key_file_contents = match fs::read_to_string("api-key.json") {
            Ok(data) => data,
            Err(e) => panic!("{:#?}", e),
        };
        let api_key_parse: serde_json::Value = match serde_json::from_str(&key_file_contents) {
            Ok(data) => data,
            Err(e) => panic!("{:#?}", e),
        };

        *self = config_parse;
        self.api_key = api_key_parse["api_key"].as_str().unwrap().to_owned();
    }
}

struct Ips {
    ipv4: String,
    ipv6base: String,
}

impl Ips {
    fn new() -> Ips {
        Ips {
            ipv4: "0.0.0.0".to_string(),
            ipv6base: ":".to_string(),
        }
    }

    fn get(&mut self, ipv6_interface: &str) {
        let ipv4uri = "https://am.i.mullvad.net/ip";
        let ipv6uri = "https://ipv6.am.i.mullvad.net/ip";

        let response = get(ipv4uri);

        match response {
            Ok(data) => self.ipv4 = data.text().expect("0.0.0.0").trim_end().to_owned(),
            Err(e) => {
                println!("Could not fetch IPv4, quitting");
                exit(75);
            }
        }

        let response = get(ipv6uri);

        match response {
            Ok(data) => {
                let ipv6 = match data.text() {
                    Ok(ip) => {ip},
                    Err(_) => {panic!("Expected IP, found none")},
                };
                let stripped = match ipv6.trim_end().strip_suffix(ipv6_interface) {
                    Some(string) => string.to_string(),
                    None => ":".to_string(),
                };
                self.ipv6base = stripped;
            }
            Err(e) => {
                println!("Could not fetch IPv6, quitting");
                exit(75);
            }
        }
    }
}

fn update_dns() {
    let mut config = DnsConfig::new();
    config.load();

    /* while (true) {} */

    let mut ips = Ips::new();
    ips.get(&config.ipv6_interface);

    let mut change4 = ChangeTracker::new();

    let mut change6 = ChangeTracker::new();

    for zone in config.zones {
        let mut agent = cloudflare::Instance::new(&config.api_key);

        agent.load_entries(&zone.email, &zone.id);

        for entry in zone.dns_entries {
            let mut found4 = false;
            let mut found6 = false;

            for cloudflare_entry in &agent.dns_entries {
                if cloudflare_entry.is_equal(&entry.name) {
                    if cloudflare_entry.r#type == cloudflare::CloudflareDnsType::A && entry.type4 {
                        found4 = true;
                        if cloudflare_entry.is_ip_new(&ips.ipv4) {
                            let success = agent.update_entry(cloudflare_entry, &ips.ipv4);
                            if success {
                                change4.updated += 1
                            } else {
                                change4.error += 1
                            }
                        } else {
                            change4.unchanged += 1;
                        }
                    }

                    if cloudflare_entry.r#type == cloudflare::CloudflareDnsType::AAAA && entry.type6
                    {
                        found6 = true;
                        let ipv6 = ips.ipv6base.clone() + entry.interface.as_ref().unwrap();

                        if cloudflare_entry.is_ip_new(&ipv6) {
                            let success = agent.update_entry(cloudflare_entry, &ipv6);
                            if success {
                                change6.updated += 1
                            } else {
                                change6.error += 1
                            }
                        } else {
                            change6.unchanged += 1;
                        }
                    }
                }

                //println!("{:#?}", entry.subdomain); // DEBUG
            }

            if !found4 && entry.type4 {
                let success = agent.create_entry(&zone.id, "A", &entry.name, &ips.ipv4);
                if success {
                    change4.created += 1
                };
            }

            if !found6 && entry.type6 {
                let ipv6 = ips.ipv6base.clone() + entry.interface.as_ref().unwrap();
                let success = agent.create_entry(&zone.id, "AAAA", &entry.name, &ipv6);
                if success {
                    change6.created += 1
                };
            }
        }

        //println!("{:#?}", zone.domain); // DEBUG
    }
    println!("++++A Records+++");
    change4.print("simple");
    println!("++AAAA Records++");
    change6.print("simple")
}

fn main() {

    let mut now = Utc::now() - Duration::seconds(59);
    let mut current = now;

    println!("Initial Time is {} {}", now.format("%H:%M:%S"), now.timezone());

    loop {
        now = Utc::now();
        if now >= current + Duration::seconds(60) {
            current = now;

            println!("Starting DNS Update at {} {}", now.format("%H:%M:%S"), now.timezone());
            update_dns();
        }
        else {
            sleep(std::time::Duration::from_millis(500));
        }
    }
}