/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

use std::rc::Rc;

use bluetooth_traits::blocklist::{uuid_is_blocklisted, Blocklist};
use bluetooth_traits::{BluetoothRequest, BluetoothResponse};
use dom_struct::dom_struct;
use ipc_channel::ipc::IpcSender;

use crate::dom::bindings::cell::DomRefCell;
use crate::dom::bindings::codegen::Bindings::BluetoothRemoteGATTCharacteristicBinding::BluetoothRemoteGATTCharacteristicMethods;
use crate::dom::bindings::codegen::Bindings::BluetoothRemoteGATTDescriptorBinding::BluetoothRemoteGATTDescriptorMethods;
use crate::dom::bindings::codegen::Bindings::BluetoothRemoteGATTServerBinding::BluetoothRemoteGATTServerMethods;
use crate::dom::bindings::codegen::Bindings::BluetoothRemoteGATTServiceBinding::BluetoothRemoteGATTServiceMethods;
use crate::dom::bindings::codegen::UnionTypes::ArrayBufferViewOrArrayBuffer;
use crate::dom::bindings::error::Error::{self, InvalidModification, Network, Security};
use crate::dom::bindings::reflector::{reflect_dom_object, DomObject, Reflector};
use crate::dom::bindings::root::{Dom, DomRoot};
use crate::dom::bindings::str::{ByteString, DOMString};
use crate::dom::bluetooth::{response_async, AsyncBluetoothListener};
use crate::dom::bluetoothremotegattcharacteristic::{
    BluetoothRemoteGATTCharacteristic, MAXIMUM_ATTRIBUTE_LENGTH,
};
use crate::dom::globalscope::GlobalScope;
use crate::dom::promise::Promise;
use crate::realms::InRealm;

// http://webbluetoothcg.github.io/web-bluetooth/#bluetoothremotegattdescriptor
#[dom_struct]
pub struct BluetoothRemoteGATTDescriptor {
    reflector_: Reflector,
    characteristic: Dom<BluetoothRemoteGATTCharacteristic>,
    uuid: DOMString,
    value: DomRefCell<Option<ByteString>>,
    instance_id: String,
}

impl BluetoothRemoteGATTDescriptor {
    pub fn new_inherited(
        characteristic: &BluetoothRemoteGATTCharacteristic,
        uuid: DOMString,
        instance_id: String,
    ) -> BluetoothRemoteGATTDescriptor {
        BluetoothRemoteGATTDescriptor {
            reflector_: Reflector::new(),
            characteristic: Dom::from_ref(characteristic),
            uuid,
            value: DomRefCell::new(None),
            instance_id,
        }
    }

    pub fn new(
        global: &GlobalScope,
        characteristic: &BluetoothRemoteGATTCharacteristic,
        uuid: DOMString,
        instance_id: String,
    ) -> DomRoot<BluetoothRemoteGATTDescriptor> {
        reflect_dom_object(
            Box::new(BluetoothRemoteGATTDescriptor::new_inherited(
                characteristic,
                uuid,
                instance_id,
            )),
            global,
        )
    }

    fn get_bluetooth_thread(&self) -> IpcSender<BluetoothRequest> {
        self.global().as_window().bluetooth_thread()
    }

    fn get_instance_id(&self) -> String {
        self.instance_id.clone()
    }
}

impl BluetoothRemoteGATTDescriptorMethods for BluetoothRemoteGATTDescriptor {
    // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-characteristic
    fn Characteristic(&self) -> DomRoot<BluetoothRemoteGATTCharacteristic> {
        DomRoot::from_ref(&self.characteristic)
    }

    // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-uuid
    fn Uuid(&self) -> DOMString {
        self.uuid.clone()
    }

    // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-value
    fn GetValue(&self) -> Option<ByteString> {
        self.value.borrow().clone()
    }

    // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-readvalue
    fn ReadValue(&self, comp: InRealm) -> Rc<Promise> {
        let p = Promise::new_in_current_realm(comp);

        // Step 1.
        if uuid_is_blocklisted(self.uuid.as_ref(), Blocklist::Reads) {
            p.reject_error(Security);
            return p;
        }

        // Step 2.
        if !self
            .Characteristic()
            .Service()
            .Device()
            .get_gatt()
            .Connected()
        {
            p.reject_error(Network);
            return p;
        }

        // TODO: Step 5: Implement the `connection-checking-wrapper` algorithm for BluetoothRemoteGATTServer.
        // Note: Steps 3 - 4 and substeps of Step 5 are implemented in components/bluetooth/lib.rs
        // in readValue function and in handle_response function.
        let sender = response_async(&p, self);
        self.get_bluetooth_thread()
            .send(BluetoothRequest::ReadValue(self.get_instance_id(), sender))
            .unwrap();
        p
    }

    // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-writevalue
    fn WriteValue(&self, value: ArrayBufferViewOrArrayBuffer, comp: InRealm) -> Rc<Promise> {
        let p = Promise::new_in_current_realm(comp);

        // Step 1.
        if uuid_is_blocklisted(self.uuid.as_ref(), Blocklist::Writes) {
            p.reject_error(Security);
            return p;
        }

        // Step 2 - 3.
        let vec = match value {
            ArrayBufferViewOrArrayBuffer::ArrayBufferView(avb) => avb.to_vec(),
            ArrayBufferViewOrArrayBuffer::ArrayBuffer(ab) => ab.to_vec(),
        };
        if vec.len() > MAXIMUM_ATTRIBUTE_LENGTH {
            p.reject_error(InvalidModification);
            return p;
        }

        // Step 4.
        if !self
            .Characteristic()
            .Service()
            .Device()
            .get_gatt()
            .Connected()
        {
            p.reject_error(Network);
            return p;
        }

        // TODO: Step 7: Implement the `connection-checking-wrapper` algorithm for BluetoothRemoteGATTServer.
        // Note: Steps 5 - 6 and substeps of Step 7 are implemented in components/bluetooth/lib.rs
        // in writeValue function and in handle_response function.
        let sender = response_async(&p, self);
        self.get_bluetooth_thread()
            .send(BluetoothRequest::WriteValue(
                self.get_instance_id(),
                vec,
                sender,
            ))
            .unwrap();
        p
    }
}

impl AsyncBluetoothListener for BluetoothRemoteGATTDescriptor {
    fn handle_response(&self, response: BluetoothResponse, promise: &Rc<Promise>) {
        match response {
            // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-readvalue
            BluetoothResponse::ReadValue(result) => {
                // TODO: Step 5.4.1: Implement activeAlgorithms internal slot for BluetoothRemoteGATTServer.

                // Step 5.4.2.
                // TODO(#5014): Replace ByteString with ArrayBuffer when it is implemented.
                let value = ByteString::new(result);
                *self.value.borrow_mut() = Some(value.clone());

                // Step 5.4.3.
                promise.resolve_native(&value);
            },
            // https://webbluetoothcg.github.io/web-bluetooth/#dom-bluetoothremotegattdescriptor-writevalue
            BluetoothResponse::WriteValue(result) => {
                // TODO: Step 7.4.1: Implement activeAlgorithms internal slot for BluetoothRemoteGATTServer.

                // Step 7.4.2.
                // TODO(#5014): Replace ByteString with an ArrayBuffer wrapped in a DataView.
                *self.value.borrow_mut() = Some(ByteString::new(result));

                // Step 7.4.3.
                // TODO: Resolve promise with undefined instead of a value.
                promise.resolve_native(&());
            },
            _ => promise.reject_error(Error::Type("Something went wrong...".to_owned())),
        }
    }
}