use std::time::Duration;

use anyhow::{anyhow, Result};

use crate::config::{
  ConfigOpts, ConfigOptsAcme, ConfigOptsConsul, ConfigOptsFirewall, ConfigOptsIgd,
};

// This code is inspired by the Trunk crate (https://github.com/thedodd/trunk)

// In this file, we take ConfigOpts and transform them into ready-to-use
// RuntimeConfig. We apply default values and business logic.

// Consul config is mandatory, all the others are optional.

#[derive(Debug)]
pub struct RuntimeConfigConsul {
  pub node_name: String,
  pub url: String,
}

#[derive(Debug)]
pub struct RuntimeConfigAcme {
  pub email: String,
}

#[derive(Debug)]
pub struct RuntimeConfigFirewall {
  pub refresh_time: Duration,
}

#[derive(Debug)]
pub struct RuntimeConfigIgd {
  pub private_ip: String,
  pub expiration_time: Duration,
  pub refresh_time: Duration,
}

#[derive(Debug)]
pub struct RuntimeConfig {
  pub consul: RuntimeConfigConsul,
  pub acme: Option<RuntimeConfigAcme>,
  pub firewall: Option<RuntimeConfigFirewall>,
  pub igd: Option<RuntimeConfigIgd>,
}

impl RuntimeConfig {
  pub fn new(opts: ConfigOpts) -> Result<Self> {
    let consul = RuntimeConfigConsul::new(opts.consul)?;
    let acme = RuntimeConfigAcme::new(opts.acme)?;
    let firewall = RuntimeConfigFirewall::new(opts.firewall)?;
    let igd = RuntimeConfigIgd::new(opts.igd)?;

    Ok(Self {
      acme,
      consul,
      firewall,
      igd,
    })
  }
}

impl RuntimeConfigConsul {
  pub(super) fn new(opts: ConfigOptsConsul) -> Result<Self> {
    let node_name = match opts.node_name {
      Some(n) => n,
      _ => return Err(anyhow!("'DIPLONAT_CONSUL_NODE_NAME' is required")),
    };
    let url = match opts.url {
      Some(url) => url,
      _ => super::CONSUL_URL.to_string(),
    };

    Ok(Self { node_name, url })
  }
}

impl RuntimeConfigAcme {
  pub fn new(opts: ConfigOptsAcme) -> Result<Option<Self>> {
    if !opts.enable {
      return Ok(None)
    };

    let email = match opts.email {
      Some(email) => email,
      _ => {
        return Err(anyhow!(
          "'DIPLONAT_ACME_EMAIL' is required if ACME is enabled"
        ))
      }
    };

    Ok(Some(Self { email }))
  }
}

impl RuntimeConfigFirewall {
  pub(super) fn new(opts: ConfigOptsFirewall) -> Result<Option<Self>> {
    if !opts.enable {
      return Ok(None)
    }

    let refresh_time = Duration::from_secs(
      match opts.refresh_time {
        Some(t) => t,
        _ => super::REFRESH_TIME,
      }
      .into(),
    );

    Ok(Some(Self { refresh_time }))
  }
}

impl RuntimeConfigIgd {
  pub(super) fn new(opts: ConfigOptsIgd) -> Result<Option<Self>> {
    if !opts.enable {
      return Ok(None)
    }

    let private_ip = match opts.private_ip {
      Some(ip) => ip,
      _ => {
        return Err(anyhow!(
          "'DIPLONAT_IGD_PRIVATE_IP' is required if IGD is enabled"
        ))
      }
    };

    let expiration_time = Duration::from_secs(
      match opts.expiration_time {
        Some(t) => t.into(),
        _ => super::EXPIRATION_TIME,
      }
      .into(),
    );
    let refresh_time = Duration::from_secs(
      match opts.refresh_time {
        Some(t) => t,
        _ => super::REFRESH_TIME,
      }
      .into(),
    );

    if refresh_time.as_secs() * 2 > expiration_time.as_secs() {
      return Err(anyhow!(
        "IGD expiration time (currently: {}s) must be at least twice bigger than refresh time \
         (currently: {}s)",
        expiration_time.as_secs(),
        refresh_time.as_secs()
      ))
    }

    Ok(Some(Self {
      private_ip,
      expiration_time,
      refresh_time,
    }))
  }
}