use std::collections::HashMap;

use prettytable::{row, Table};

use crate::constants;
use crate::devices::device::{Device, DeviceId, DeviceRelay, DeviceRelayID};
use crate::energy::consumption::EnergyConsumption;
use crate::utils::time_utils::time_secs;

#[derive(Default)]
pub struct DeviceState {
    pub last_ping: u64,
}

impl DeviceState {
    pub fn record_ping(&mut self) {
        self.last_ping = time_secs();
    }

    pub fn is_online(&self) -> bool {
        (time_secs() - self.last_ping) < constants::DEVICE_MAX_PING_TIME
    }
}

#[derive(Default, Clone)]
pub struct RelayState {
    on: bool,
    since: usize,
}

impl RelayState {
    fn is_on(&self) -> bool {
        self.on
    }

    fn is_off(&self) -> bool {
        !self.on
    }
}

type RelaysState = HashMap<DeviceRelayID, RelayState>;

#[derive(Default)]
pub struct EnergyEngine {
    devices_state: HashMap<DeviceId, DeviceState>,
    relays_state: RelaysState,
}

impl DeviceRelay {
    // Note : this function is not recursive
    fn has_running_dependencies(&self, s: &RelaysState, devices: &[Device]) -> bool {
        for d in devices {
            for r in &d.relays {
                if r.depends_on.contains(&self.id) && s.get(&r.id).unwrap().is_on() {
                    return true;
                }
            }
        }

        false
    }

    // Note : this function is not recursive
    fn is_missing_dependencies(&self, s: &RelaysState) -> bool {
        self.depends_on.iter().any(|id| s.get(id).unwrap().is_off())
    }

    fn is_having_conflict(&self, s: &RelaysState, devices: &[Device]) -> bool {
        if self
            .conflicts_with
            .iter()
            .any(|id| s.get(id).unwrap().is_on())
        {
            return true;
        }

        // Reverse search
        for device in devices {
            for r in &device.relays {
                if s.get(&r.id).unwrap().is_on() && r.conflicts_with.contains(&self.id) {
                    return true;
                }
            }
        }

        false
    }
}

impl EnergyEngine {
    pub fn device_state(&mut self, dev_id: &DeviceId) -> &mut DeviceState {
        self.devices_state.entry(dev_id.clone()).or_default();
        self.devices_state.get_mut(dev_id).unwrap()
    }

    pub fn relay_state(&mut self, relay_id: DeviceRelayID) -> &mut RelayState {
        self.relays_state.entry(relay_id).or_default();
        self.relays_state.get_mut(&relay_id).unwrap()
    }

    fn print_summary(&mut self, curr_consumption: EnergyConsumption, devices: &[Device]) {
        log::info!("Current consumption: {curr_consumption}");

        let mut table = Table::new();
        table.add_row(row!["Device", "Relay", "On", "Since"]);
        for d in devices {
            for r in &d.relays {
                let status = self.relay_state(r.id);
                table.add_row(row![
                    d.name,
                    r.name,
                    status.is_on().to_string(),
                    status.since
                ]);
            }
        }
        table.printstd();
    }

    pub fn refresh(&mut self, curr_consumption: EnergyConsumption, devices: &[Device]) {
        // Force creation of missing relays state
        for d in devices {
            for r in &d.relays {
                // Requesting relay state is enough to trigger relay creation
                self.relay_state(r.id);
            }
        }

        let mut new_relays_state = self.relays_state.clone();

        // Forcefully turn off relays that belongs to offline devices
        for d in devices {
            if !self.device_state(&d.id).is_online() {
                for r in &d.relays {
                    new_relays_state.get_mut(&r.id).unwrap().on = false;
                }
            }
        }

        // Forcefully turn off disabled relays
        for d in devices {
            for r in &d.relays {
                if !r.enabled || !d.enabled {
                    new_relays_state.get_mut(&r.id).unwrap().on = false;
                }
            }
        }

        // Forcefully turn off relays with missing dependency
        loop {
            let mut changed = false;

            for d in devices {
                for r in &d.relays {
                    if new_relays_state.get(&r.id).unwrap().is_off() {
                        continue;
                    }

                    // Check if any dependency of relay is off
                    if r.is_missing_dependencies(&new_relays_state) {
                        new_relays_state.get_mut(&r.id).unwrap().on = false;
                        changed = true;
                    }
                }
            }

            if !changed {
                break;
            }
        }

        // Virtually turn off all relays that can be stopped
        loop {
            let mut changed = false;

            for d in devices {
                for r in &d.relays {
                    let state = new_relays_state.get(&r.id).unwrap();
                    if state.is_off() {
                        continue;
                    }

                    // Check if minimal runtime has not been reached
                    if (state.since + r.minimal_uptime) as i64 > time_secs() as i64 {
                        continue;
                    }

                    // Check that no relay that depends on this relay are turned on
                    if r.has_running_dependencies(&new_relays_state, devices) {
                        continue;
                    }

                    new_relays_state.get_mut(&r.id).unwrap().on = false;
                    changed = true;
                }
            }

            if !changed {
                break;
            }
        }

        // TODO Turn on relays with running constraints (only ENABLED)

        // Order relays
        let mut ordered_relays = devices
            .iter()
            .filter(|d| self.device_state(&d.id).is_online() && d.enabled)
            .flat_map(|d| &d.relays)
            .filter(|r| r.enabled)
            .collect::<Vec<_>>();
        ordered_relays.sort_by_key(|r| r.priority);
        ordered_relays.reverse();

        loop {
            let mut changed = false;
            for relay in &ordered_relays {
                if new_relays_state.get(&relay.id).unwrap().is_on() {
                    continue;
                }

                if !relay.enabled {
                    continue;
                }

                let real_relay_state = self.relays_state.get(&relay.id).unwrap();
                if real_relay_state.is_off()
                    && (real_relay_state.since + relay.minimal_downtime) as u64 > time_secs()
                {
                    continue;
                }

                if relay.is_missing_dependencies(&new_relays_state) {
                    continue;
                }

                if relay.is_having_conflict(&new_relays_state, devices) {
                    continue;
                }

                // TODO : check consumption
                log::info!("Turn on relay {}", relay.name);
                new_relays_state.get_mut(&relay.id).unwrap().on = true;
                changed = true;
            }

            if !changed {
                break;
            }
        }

        // Commit changes
        for (id, new_state) in &new_relays_state {
            let curr_state = self.relay_state(*id);
            if curr_state.on != new_state.on {
                curr_state.on = new_state.on;
                curr_state.since = time_secs() as usize;
                log::info!("Changing state of {id:?} to {}", new_state.on);
            }
        }

        self.print_summary(curr_consumption, devices);
    }
}