/* 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 dom_struct::dom_struct;
use js::rust::HandleObject;
use msg::constellation_msg::PipelineId;
use servo_media::audio::context::{LatencyCategory, ProcessingState, RealTimeAudioContextOptions};

use crate::dom::baseaudiocontext::{BaseAudioContext, BaseAudioContextOptions};
use crate::dom::bindings::codegen::Bindings::AudioContextBinding::{
    AudioContextLatencyCategory, AudioContextMethods, AudioContextOptions, AudioTimestamp,
};
use crate::dom::bindings::codegen::Bindings::AudioNodeBinding::AudioNodeOptions;
use crate::dom::bindings::codegen::Bindings::BaseAudioContextBinding::AudioContextState;
use crate::dom::bindings::codegen::Bindings::BaseAudioContextBinding::BaseAudioContext_Binding::BaseAudioContextMethods;
use crate::dom::bindings::codegen::UnionTypes::AudioContextLatencyCategoryOrDouble;
use crate::dom::bindings::error::{Error, Fallible};
use crate::dom::bindings::inheritance::Castable;
use crate::dom::bindings::num::Finite;
use crate::dom::bindings::refcounted::{Trusted, TrustedPromise};
use crate::dom::bindings::reflector::{reflect_dom_object_with_proto, DomObject};
use crate::dom::bindings::root::DomRoot;
use crate::dom::htmlmediaelement::HTMLMediaElement;
use crate::dom::mediaelementaudiosourcenode::MediaElementAudioSourceNode;
use crate::dom::mediastream::MediaStream;
use crate::dom::mediastreamaudiodestinationnode::MediaStreamAudioDestinationNode;
use crate::dom::mediastreamaudiosourcenode::MediaStreamAudioSourceNode;
use crate::dom::mediastreamtrack::MediaStreamTrack;
use crate::dom::mediastreamtrackaudiosourcenode::MediaStreamTrackAudioSourceNode;
use crate::dom::promise::Promise;
use crate::dom::window::Window;
use crate::realms::InRealm;
use crate::task_source::TaskSource;

#[dom_struct]
pub struct AudioContext {
    context: BaseAudioContext,
    latency_hint: AudioContextLatencyCategory,
    /// <https://webaudio.github.io/web-audio-api/#dom-audiocontext-baselatency>
    base_latency: f64,
    /// <https://webaudio.github.io/web-audio-api/#dom-audiocontext-outputlatency>
    output_latency: f64,
}

impl AudioContext {
    #[allow(crown::unrooted_must_root)]
    // https://webaudio.github.io/web-audio-api/#AudioContext-constructors
    fn new_inherited(options: &AudioContextOptions, pipeline_id: PipelineId) -> AudioContext {
        // Steps 1-3.
        let context = BaseAudioContext::new_inherited(
            BaseAudioContextOptions::AudioContext(options.into()),
            pipeline_id,
        );

        // Step 4.1.
        let latency_hint = match options.latencyHint {
            AudioContextLatencyCategoryOrDouble::AudioContextLatencyCategory(category) => category,
            AudioContextLatencyCategoryOrDouble::Double(_) => {
                AudioContextLatencyCategory::Interactive
            }, // TODO
        };

        // Step 4.2. The sample rate is set during the creation of the BaseAudioContext.
        // servo-media takes care of setting the default sample rate of the output device
        // and of resampling the audio output if needed.

        // Steps 5 and 6 of the construction algorithm will happen in `resume`,
        // after reflecting dom object.

        AudioContext {
            context,
            latency_hint,
            base_latency: 0.,   // TODO
            output_latency: 0., // TODO
        }
    }

    #[allow(crown::unrooted_must_root)]
    fn new(
        window: &Window,
        proto: Option<HandleObject>,
        options: &AudioContextOptions,
    ) -> DomRoot<AudioContext> {
        let pipeline_id = window.pipeline_id();
        let context = AudioContext::new_inherited(options, pipeline_id);
        let context = reflect_dom_object_with_proto(Box::new(context), window, proto);
        context.resume();
        context
    }

    // https://webaudio.github.io/web-audio-api/#AudioContext-constructors
    #[allow(non_snake_case)]
    pub fn Constructor(
        window: &Window,
        proto: Option<HandleObject>,
        options: &AudioContextOptions,
    ) -> Fallible<DomRoot<AudioContext>> {
        Ok(AudioContext::new(window, proto, options))
    }

    fn resume(&self) {
        // Step 5.
        if self.context.is_allowed_to_start() {
            // Step 6.
            self.context.resume();
        }
    }

    pub fn base(&self) -> DomRoot<BaseAudioContext> {
        DomRoot::from_ref(&self.context)
    }
}

impl AudioContextMethods for AudioContext {
    // https://webaudio.github.io/web-audio-api/#dom-audiocontext-baselatency
    fn BaseLatency(&self) -> Finite<f64> {
        Finite::wrap(self.base_latency)
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiocontext-outputlatency
    fn OutputLatency(&self) -> Finite<f64> {
        Finite::wrap(self.output_latency)
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiocontext-outputlatency
    fn GetOutputTimestamp(&self) -> AudioTimestamp {
        // TODO
        AudioTimestamp {
            contextTime: Some(Finite::wrap(0.)),
            performanceTime: Some(Finite::wrap(0.)),
        }
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiocontext-suspend
    fn Suspend(&self, comp: InRealm) -> Rc<Promise> {
        // Step 1.
        let promise = Promise::new_in_current_realm(comp);

        // Step 2.
        if self.context.control_thread_state() == ProcessingState::Closed {
            promise.reject_error(Error::InvalidState);
            return promise;
        }

        // Step 3.
        if self.context.State() == AudioContextState::Suspended {
            promise.resolve_native(&());
            return promise;
        }

        // Steps 4 and 5.
        let window = DomRoot::downcast::<Window>(self.global()).unwrap();
        let task_source = window.task_manager().dom_manipulation_task_source();
        let trusted_promise = TrustedPromise::new(promise.clone());
        match self.context.audio_context_impl().lock().unwrap().suspend() {
            Ok(_) => {
                let base_context = Trusted::new(&self.context);
                let context = Trusted::new(self);
                let _ = task_source.queue(
                    task!(suspend_ok: move || {
                        let base_context = base_context.root();
                        let context = context.root();
                        let promise = trusted_promise.root();
                        promise.resolve_native(&());
                        if base_context.State() != AudioContextState::Suspended {
                            base_context.set_state_attribute(AudioContextState::Suspended);
                            let window = DomRoot::downcast::<Window>(context.global()).unwrap();
                            window.task_manager().dom_manipulation_task_source().queue_simple_event(
                                context.upcast(),
                                atom!("statechange"),
                                &window
                                );
                        }
                    }),
                    window.upcast(),
                );
            },
            Err(_) => {
                // The spec does not define the error case and `suspend` should
                // never fail, but we handle the case here for completion.
                let _ = task_source.queue(
                    task!(suspend_error: move || {
                        let promise = trusted_promise.root();
                        promise.reject_error(Error::Type("Something went wrong".to_owned()));
                    }),
                    window.upcast(),
                );
            },
        };

        // Step 6.
        promise
    }

    // https://webaudio.github.io/web-audio-api/#dom-audiocontext-close
    fn Close(&self, comp: InRealm) -> Rc<Promise> {
        // Step 1.
        let promise = Promise::new_in_current_realm(comp);

        // Step 2.
        if self.context.control_thread_state() == ProcessingState::Closed {
            promise.reject_error(Error::InvalidState);
            return promise;
        }

        // Step 3.
        if self.context.State() == AudioContextState::Closed {
            promise.resolve_native(&());
            return promise;
        }

        // Steps 4 and 5.
        let window = DomRoot::downcast::<Window>(self.global()).unwrap();
        let task_source = window.task_manager().dom_manipulation_task_source();
        let trusted_promise = TrustedPromise::new(promise.clone());
        match self.context.audio_context_impl().lock().unwrap().close() {
            Ok(_) => {
                let base_context = Trusted::new(&self.context);
                let context = Trusted::new(self);
                let _ = task_source.queue(
                    task!(suspend_ok: move || {
                        let base_context = base_context.root();
                        let context = context.root();
                        let promise = trusted_promise.root();
                        promise.resolve_native(&());
                        if base_context.State() != AudioContextState::Closed {
                            base_context.set_state_attribute(AudioContextState::Closed);
                            let window = DomRoot::downcast::<Window>(context.global()).unwrap();
                            window.task_manager().dom_manipulation_task_source().queue_simple_event(
                                context.upcast(),
                                atom!("statechange"),
                                &window
                                );
                        }
                    }),
                    window.upcast(),
                );
            },
            Err(_) => {
                // The spec does not define the error case and `suspend` should
                // never fail, but we handle the case here for completion.
                let _ = task_source.queue(
                    task!(suspend_error: move || {
                        let promise = trusted_promise.root();
                        promise.reject_error(Error::Type("Something went wrong".to_owned()));
                    }),
                    window.upcast(),
                );
            },
        };

        // Step 6.
        promise
    }

    /// <https://webaudio.github.io/web-audio-api/#dom-audiocontext-createmediaelementsource>
    fn CreateMediaElementSource(
        &self,
        media_element: &HTMLMediaElement,
    ) -> Fallible<DomRoot<MediaElementAudioSourceNode>> {
        let global = self.global();
        let window = global.as_window();
        MediaElementAudioSourceNode::new(window, self, media_element)
    }

    /// <https://webaudio.github.io/web-audio-api/#dom-audiocontext-createmediastreamsource>
    fn CreateMediaStreamSource(
        &self,
        stream: &MediaStream,
    ) -> Fallible<DomRoot<MediaStreamAudioSourceNode>> {
        let global = self.global();
        let window = global.as_window();
        MediaStreamAudioSourceNode::new(window, self, stream)
    }

    /// <https://webaudio.github.io/web-audio-api/#dom-audiocontext-createmediastreamtracksource>
    fn CreateMediaStreamTrackSource(
        &self,
        track: &MediaStreamTrack,
    ) -> Fallible<DomRoot<MediaStreamTrackAudioSourceNode>> {
        let global = self.global();
        let window = global.as_window();
        MediaStreamTrackAudioSourceNode::new(window, self, track)
    }

    /// <https://webaudio.github.io/web-audio-api/#dom-audiocontext-createmediastreamdestination>
    fn CreateMediaStreamDestination(&self) -> Fallible<DomRoot<MediaStreamAudioDestinationNode>> {
        let global = self.global();
        let window = global.as_window();
        MediaStreamAudioDestinationNode::new(window, self, &AudioNodeOptions::empty())
    }
}

impl From<AudioContextLatencyCategory> for LatencyCategory {
    fn from(category: AudioContextLatencyCategory) -> Self {
        match category {
            AudioContextLatencyCategory::Balanced => LatencyCategory::Balanced,
            AudioContextLatencyCategory::Interactive => LatencyCategory::Interactive,
            AudioContextLatencyCategory::Playback => LatencyCategory::Playback,
        }
    }
}

impl<'a> From<&'a AudioContextOptions> for RealTimeAudioContextOptions {
    fn from(options: &AudioContextOptions) -> Self {
        Self {
            sample_rate: *options.sampleRate.unwrap_or(Finite::wrap(44100.)),
            latency_hint: match options.latencyHint {
                AudioContextLatencyCategoryOrDouble::AudioContextLatencyCategory(category) => {
                    category.into()
                },
                AudioContextLatencyCategoryOrDouble::Double(_) => LatencyCategory::Interactive, // TODO
            },
        }
    }
}