use bevy::prelude::*;
use bevy_replicon::prelude::{ClientState, FromClient, SendMode, ServerTriggerExt, ToClients};
use shared::{
    GameState,
    backpack::{
        BackbackSwapEvent, Backpack, UiHeadState,
        backpack_ui::{BackpackUiState, HEAD_SLOTS},
    },
    control::{
        BackpackLeftPressed, BackpackRightPressed, BackpackSwapPressed, BackpackTogglePressed,
    },
    protocol::{ClientToController, PlaySound},
};

pub fn plugin(app: &mut App) {
    app.add_systems(
        FixedUpdate,
        sync_on_change.run_if(in_state(GameState::Playing)),
    );
    app.add_systems(
        FixedUpdate,
        swap_head_inputs.run_if(in_state(ClientState::Disconnected)),
    );
}

#[allow(clippy::too_many_arguments)]
fn swap_head_inputs(
    backpacks: Query<Ref<Backpack>>,
    clients: ClientToController,
    mut backpack_toggles: MessageReader<FromClient<BackpackTogglePressed>>,
    mut backpack_lefts: MessageReader<FromClient<BackpackLeftPressed>>,
    mut backpack_rights: MessageReader<FromClient<BackpackRightPressed>>,
    mut backpack_swaps: MessageReader<FromClient<BackpackSwapPressed>>,
    mut commands: Commands,
    mut state: Single<&mut BackpackUiState>,
    time: Res<Time>,
) {
    for _ in backpack_toggles.read() {
        if state.count == 0 {
            return;
        }

        state.open = !state.open;
        commands.server_trigger(ToClients {
            mode: SendMode::Broadcast,
            message: PlaySound::Backpack { open: state.open },
        });
    }

    for press in backpack_lefts.read() {
        let player = clients.get_controller(press.client_id);
        let backpack = backpacks.get(player).unwrap();

        if !state.open {
            return;
        }

        if state.current_slot > 0 {
            state.current_slot -= 1;

            commands.server_trigger(ToClients {
                mode: SendMode::Broadcast,
                message: PlaySound::Selection,
            });
            sync(&backpack, &mut state, time.elapsed_secs());
        }
    }

    for press in backpack_rights.read() {
        let player = clients.get_controller(press.client_id);
        let backpack = backpacks.get(player).unwrap();

        if !state.open {
            return;
        }

        if state.current_slot < state.count.saturating_sub(1) {
            state.current_slot += 1;

            commands.server_trigger(ToClients {
                mode: SendMode::Broadcast,
                message: PlaySound::Selection,
            });
            sync(&backpack, &mut state, time.elapsed_secs());
        }
    }

    for _ in backpack_swaps.read() {
        if !state.open {
            return;
        }

        commands.trigger(BackbackSwapEvent(state.current_slot));
    }
}

fn sync_on_change(
    backpack: Query<Ref<Backpack>>,
    mut state: Single<&mut BackpackUiState>,
    time: Res<Time>,
) {
    for backpack in backpack.iter() {
        if backpack.is_changed() || backpack.reloading() {
            sync(&backpack, &mut state, time.elapsed_secs());
        }
    }
}

fn sync(backpack: &Backpack, state: &mut Single<&mut BackpackUiState>, time: f32) {
    state.count = backpack.heads.len();

    state.scroll = state.scroll.min(state.count.saturating_sub(HEAD_SLOTS));

    if state.current_slot >= state.scroll + HEAD_SLOTS {
        state.scroll = state.current_slot.saturating_sub(HEAD_SLOTS - 1);
    }
    if state.current_slot < state.scroll {
        state.scroll = state.current_slot;
    }

    for i in 0..HEAD_SLOTS {
        if let Some(head) = backpack.heads.get(i + state.scroll) {
            state.heads[i] = Some(UiHeadState::new(*head, time));
        } else {
            state.heads[i] = None;
        }
    }
}