use core_foundation_sys::base::OSStatus;
use std::ops::Deref;

use coremidi_sys::{
    ItemCount, MIDIEndpointDispose, MIDIEndpointRef, MIDIGetNumberOfSources, MIDIGetSource,
    MIDIReceived, MIDIReceivedEventList,
};

use crate::endpoints::endpoint::Endpoint;
use crate::ports::Packets;
use crate::Object;

/// A [MIDI source](https://developer.apple.com/documentation/coremidi/midiendpointref) owned by an entity.
///
/// A source can be created from an index like this:
///
/// ```rust,no_run
/// let source = coremidi::Source::from_index(0).unwrap();
/// println!("The source at index 0 has display name '{}'", source.display_name().unwrap());
/// ```
///
#[derive(Debug, Hash, Eq, PartialEq)]
pub struct Source {
    pub(crate) endpoint: Endpoint,
}

impl Source {
    pub(crate) fn new(endpoint_ref: MIDIEndpointRef) -> Self {
        Self {
            endpoint: Endpoint::new(endpoint_ref),
        }
    }

    /// Create a source endpoint from its index.
    /// See [MIDIGetSource](https://developer.apple.com/documentation/coremidi/1495168-midigetsource)
    ///
    pub fn from_index(index: usize) -> Option<Source> {
        let endpoint_ref = unsafe { MIDIGetSource(index as ItemCount) };
        match endpoint_ref {
            0 => None,
            _ => Some(Self::new(endpoint_ref)),
        }
    }

    /// Create a source endpoint from its name.
    pub fn from_name(name: &str) -> Option<Source> {
        Sources
            .into_iter()
            .find(|source| source.name().as_deref() == Some(name))
    }
}

impl Clone for Source {
    fn clone(&self) -> Self {
        Self::new(self.endpoint.object.0)
    }
}

impl AsRef<Object> for Source {
    fn as_ref(&self) -> &Object {
        &self.endpoint.object
    }
}

impl AsRef<Endpoint> for Source {
    fn as_ref(&self) -> &Endpoint {
        &self.endpoint
    }
}

impl Deref for Source {
    type Target = Endpoint;

    fn deref(&self) -> &Endpoint {
        &self.endpoint
    }
}

/// Source endpoints available in the system.
///
/// The number of sources available in the system can be retrieved with:
///
/// ```rust,no_run
/// let number_of_sources = coremidi::Sources::count();
/// ```
///
/// The sources in the system can be iterated as:
///
/// ```rust,no_run
/// for source in coremidi::Sources {
///   println!("{}", source.display_name().unwrap());
/// }
/// ```
///
pub struct Sources;

impl Sources {
    /// Get the number of sources available in the system for receiving MIDI messages.
    /// See [MIDIGetNumberOfSources](https://developer.apple.com/documentation/coremidi/1495116-midigetnumberofsources).
    ///
    pub fn count() -> usize {
        unsafe { MIDIGetNumberOfSources() as usize }
    }
}

impl IntoIterator for Sources {
    type Item = Source;
    type IntoIter = SourcesIterator;

    fn into_iter(self) -> Self::IntoIter {
        SourcesIterator {
            index: 0,
            count: Self::count(),
        }
    }
}

pub struct SourcesIterator {
    index: usize,
    count: usize,
}

impl Iterator for SourcesIterator {
    type Item = Source;

    fn next(&mut self) -> Option<Source> {
        if self.index < self.count {
            let source = Source::from_index(self.index);
            self.index += 1;
            source
        } else {
            None
        }
    }
}

/// A [MIDI virtual source](https://developer.apple.com/documentation/coremidi/1495212-midisourcecreate) owned by a client.
///
/// A virtual source can be created like:
///
/// ```rust,no_run
/// let client = coremidi::Client::new("example-client").unwrap();
/// let source = client.virtual_source("example-source").unwrap();
/// ```
///
#[derive(Debug, Hash, Eq, PartialEq)]
pub struct VirtualSource {
    pub(crate) endpoint: Endpoint,
}

impl VirtualSource {
    pub(crate) fn new(endpoint_ref: MIDIEndpointRef) -> Self {
        Self {
            endpoint: Endpoint::new(endpoint_ref),
        }
    }

    /// Distributes incoming MIDI from a source to the client input ports which are connected to that source.
    /// See [MIDIReceived](https://developer.apple.com/documentation/coremidi/1495276-midireceived)
    ///
    pub fn received<'a, P>(&self, packets: P) -> Result<(), OSStatus>
    where
        P: Into<Packets<'a>>,
    {
        let status = match packets.into() {
            Packets::BorrowedPacketList(packet_list) => unsafe {
                MIDIReceived(self.endpoint.object.0, packet_list.as_ptr())
            },
            Packets::BorrowedEventList(event_list) => unsafe {
                MIDIReceivedEventList(self.endpoint.object.0, event_list.as_ptr())
            },
            Packets::OwnedEventBuffer(event_buffer) => unsafe {
                MIDIReceivedEventList(self.endpoint.object.0, event_buffer.as_ptr())
            },
        };

        if status == 0 {
            Ok(())
        } else {
            Err(status)
        }
    }
}

impl Deref for VirtualSource {
    type Target = Endpoint;

    fn deref(&self) -> &Endpoint {
        &self.endpoint
    }
}

impl From<Object> for VirtualSource {
    fn from(object: Object) -> Self {
        Self::new(object.0)
    }
}

impl Drop for VirtualSource {
    fn drop(&mut self) {
        unsafe { MIDIEndpointDispose(self.endpoint.object.0) };
    }
}