// Copyright 2021 - Nym Technologies SA <contact@nymtech.net>
// SPDX-License-Identifier: Apache-2.0

use crate::node_status_api::utils::{NodeStatus, NodeUptimes};
use rocket::http::{ContentType, Status};
use rocket::response::{self, Responder, Response};
use rocket::Request;
use serde::{Deserialize, Serialize};
use std::convert::TryFrom;
use std::fmt::{self, Display, Formatter};
use std::io::Cursor;

// todo: put into some error enum
#[derive(Debug)]
pub struct InvalidUptime;

// value in range 0-100
#[derive(Clone, Serialize, Deserialize, Debug)]
pub struct Uptime(u8);

impl Uptime {
    pub const fn zero() -> Self {
        Uptime(0)
    }

    pub fn from_ratio(numerator: usize, denominator: usize) -> Result<Self, InvalidUptime> {
        if denominator == 0 {
            return Ok(Self::zero());
        }

        let uptime = ((numerator as f32 / denominator as f32) * 100.0) as u8;

        if uptime > 100 {
            Err(InvalidUptime)
        } else {
            Ok(Uptime(uptime))
        }
    }

    pub fn u8(&self) -> u8 {
        self.0
    }
}

impl From<Uptime> for u8 {
    fn from(uptime: Uptime) -> Self {
        uptime.0
    }
}

impl TryFrom<u8> for Uptime {
    type Error = InvalidUptime;

    fn try_from(value: u8) -> Result<Self, Self::Error> {
        if value > 100 {
            Err(InvalidUptime)
        } else {
            Ok(Uptime(value))
        }
    }
}

impl TryFrom<i64> for Uptime {
    type Error = InvalidUptime;

    fn try_from(value: i64) -> Result<Self, Self::Error> {
        if !(0..=100).contains(&value) {
            Err(InvalidUptime)
        } else {
            Ok(Uptime(value as u8))
        }
    }
}

#[derive(Clone, Serialize, Deserialize, Debug)]
pub struct MixnodeStatusReport {
    identity: String,
    owner: String,

    most_recent_ipv4: bool,
    most_recent_ipv6: bool,

    last_hour_ipv4: Uptime,
    last_hour_ipv6: Uptime,

    last_day_ipv4: Uptime,
    last_day_ipv6: Uptime,
}

impl MixnodeStatusReport {
    pub(crate) fn construct_from_last_day_reports(
        identity: String,
        owner: String,
        last_day_ipv4: Vec<NodeStatus>,
        last_day_ipv6: Vec<NodeStatus>,
    ) -> Self {
        let node_uptimes =
            NodeUptimes::calculate_from_last_day_reports(last_day_ipv4, last_day_ipv6);

        MixnodeStatusReport {
            identity,
            owner,
            most_recent_ipv4: node_uptimes.most_recent_ipv4,
            most_recent_ipv6: node_uptimes.most_recent_ipv6,
            last_hour_ipv4: node_uptimes.last_hour_ipv4,
            last_hour_ipv6: node_uptimes.last_hour_ipv6,
            last_day_ipv4: node_uptimes.last_day_ipv4,
            last_day_ipv6: node_uptimes.last_day_ipv6,
        }
    }
}

#[derive(Clone, Serialize, Deserialize, Debug)]
pub struct GatewayStatusReport {
    identity: String,
    owner: String,

    most_recent_ipv4: bool,
    most_recent_ipv6: bool,

    last_hour_ipv4: Uptime,
    last_hour_ipv6: Uptime,

    last_day_ipv4: Uptime,
    last_day_ipv6: Uptime,
}

impl GatewayStatusReport {
    pub(crate) fn construct_from_last_day_reports(
        identity: String,
        owner: String,
        last_day_ipv4: Vec<NodeStatus>,
        last_day_ipv6: Vec<NodeStatus>,
    ) -> Self {
        let node_uptimes =
            NodeUptimes::calculate_from_last_day_reports(last_day_ipv4, last_day_ipv6);

        GatewayStatusReport {
            identity,
            owner,
            most_recent_ipv4: node_uptimes.most_recent_ipv4,
            most_recent_ipv6: node_uptimes.most_recent_ipv6,
            last_hour_ipv4: node_uptimes.last_hour_ipv4,
            last_hour_ipv6: node_uptimes.last_hour_ipv6,
            last_day_ipv4: node_uptimes.last_day_ipv4,
            last_day_ipv6: node_uptimes.last_day_ipv6,
        }
    }
}

#[derive(Clone, Serialize, Deserialize, Debug)]
pub struct MixnodeUptimeHistory {
    pub(crate) identity: String,
    pub(crate) owner: String,

    pub(crate) history: Vec<HistoricalUptime>,
}

impl MixnodeUptimeHistory {
    pub(crate) fn new(identity: String, owner: String, history: Vec<HistoricalUptime>) -> Self {
        MixnodeUptimeHistory {
            identity,
            owner,
            history,
        }
    }
}

#[derive(Clone, Serialize, Deserialize, Debug)]
pub struct GatewayUptimeHistory {
    pub(crate) identity: String,
    pub(crate) owner: String,

    pub(crate) history: Vec<HistoricalUptime>,
}

impl GatewayUptimeHistory {
    pub(crate) fn new(identity: String, owner: String, history: Vec<HistoricalUptime>) -> Self {
        GatewayUptimeHistory {
            identity,
            owner,
            history,
        }
    }
}

#[derive(Clone, Serialize, Deserialize, Debug)]
pub struct HistoricalUptime {
    // ISO 8601 date string
    // I think this is more than enough, we don't need the uber precision of timezone offsets, etc
    pub(crate) date: String,

    pub(crate) ipv4_uptime: Uptime,
    pub(crate) ipv6_uptime: Uptime,
}

pub(crate) struct ErrorResponse {
    error: NodeStatusApiError,
    status: Status,
}

impl ErrorResponse {
    pub(crate) fn new(error: NodeStatusApiError, status: Status) -> Self {
        ErrorResponse { error, status }
    }
}

impl<'r, 'o: 'r> Responder<'r, 'o> for ErrorResponse {
    fn respond_to(self, _: &'r Request<'_>) -> response::Result<'o> {
        let message = format!("{}", self.error);
        Response::build()
            .header(ContentType::Plain)
            .sized_body(message.len(), Cursor::new(message))
            .status(self.status)
            .ok()
    }
}

#[derive(Debug)]
pub enum NodeStatusApiError {
    MixnodeReportNotFound(String),
    GatewayReportNotFound(String),
    MixnodeUptimeHistoryNotFound(String),
    GatewayUptimeHistoryNotFound(String),

    // I don't think we want to expose errors to the user about what really happened
    InternalDatabaseError,
}

impl Display for NodeStatusApiError {
    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
        match self {
            NodeStatusApiError::MixnodeReportNotFound(identity) => write!(
                f,
                "Could not find status report associated with mixnode {}",
                identity
            ),
            NodeStatusApiError::GatewayReportNotFound(identity) => write!(
                f,
                "Could not find status report associated with gateway {}",
                identity
            ),
            NodeStatusApiError::MixnodeUptimeHistoryNotFound(identity) => write!(
                f,
                "Could not find uptime history associated with mixnode {}",
                identity
            ),
            NodeStatusApiError::GatewayUptimeHistoryNotFound(identity) => write!(
                f,
                "Could not find uptime history associated with gateway {}",
                identity
            ),
            NodeStatusApiError::InternalDatabaseError => {
                write!(f, "The internal database has experienced an issue")
            }
        }
    }
}