// Copyright 2018 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

use std::default::Default;
use std::error;
use std::fmt::{self, Display};
use std::os::unix::io::RawFd;
use std::str::FromStr;

use audio_streams::{
    shm_streams::{NullShmStreamSource, ShmStreamSource},
    StreamEffect,
};
use libcras::CrasClient;
use resources::{Alloc, MmioType, SystemAllocator};
use sys_util::{error, EventFd, GuestMemory};

use crate::pci::ac97_bus_master::Ac97BusMaster;
use crate::pci::ac97_mixer::Ac97Mixer;
use crate::pci::ac97_regs::*;
use crate::pci::pci_configuration::{
    PciBarConfiguration, PciClassCode, PciConfiguration, PciHeaderType, PciMultimediaSubclass,
};
use crate::pci::pci_device::{self, PciDevice, Result};
use crate::pci::PciInterruptPin;

// Use 82801AA because it's what qemu does.
const PCI_DEVICE_ID_INTEL_82801AA_5: u16 = 0x2415;

/// AC97 audio device emulation.
/// Provides the PCI interface for the internal Ac97 emulation.
/// Internally the `Ac97BusMaster` and `Ac97Mixer` structs are used to emulated the bus master and
/// mixer registers respectively. `Ac97BusMaster` handles moving smaples between guest memory and
/// the audio backend.
#[derive(Debug, Clone)]
pub enum Ac97Backend {
    NULL,
    CRAS,
}

impl Default for Ac97Backend {
    fn default() -> Self {
        Ac97Backend::NULL
    }
}

/// Errors that are possible from a `Ac97`.
#[derive(Debug)]
pub enum Ac97Error {
    InvalidBackend,
}

impl error::Error for Ac97Error {}

impl Display for Ac97Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            Ac97Error::InvalidBackend => write!(f, "Must be cras or null"),
        }
    }
}

impl FromStr for Ac97Backend {
    type Err = Ac97Error;
    fn from_str(s: &str) -> std::result::Result<Self, Self::Err> {
        match s {
            "cras" => Ok(Ac97Backend::CRAS),
            "null" => Ok(Ac97Backend::NULL),
            _ => Err(Ac97Error::InvalidBackend),
        }
    }
}

/// Holds the parameters for a AC97 device
#[derive(Default, Debug, Clone)]
pub struct Ac97Parameters {
    pub backend: Ac97Backend,
    pub capture: bool,
    pub capture_effects: Vec<StreamEffect>,
}

pub struct Ac97Dev {
    config_regs: PciConfiguration,
    pci_bus_dev: Option<(u8, u8)>,
    // The irq events are temporarily saved here. They need to be passed to the device after the
    // jail forks. This happens when the bus is first written.
    irq_evt: Option<EventFd>,
    irq_resample_evt: Option<EventFd>,
    bus_master: Ac97BusMaster,
    mixer: Ac97Mixer,
}

impl Ac97Dev {
    /// Creates an 'Ac97Dev' that uses the given `GuestMemory` and starts with all registers at
    /// default values.
    pub fn new(mem: GuestMemory, audio_server: Box<dyn ShmStreamSource>) -> Self {
        let config_regs = PciConfiguration::new(
            0x8086,
            PCI_DEVICE_ID_INTEL_82801AA_5,
            PciClassCode::MultimediaController,
            &PciMultimediaSubclass::AudioDevice,
            None, // No Programming interface.
            PciHeaderType::Device,
            0x8086, // Subsystem Vendor ID
            0x1,    // Subsystem ID.
        );

        Ac97Dev {
            config_regs,
            pci_bus_dev: None,
            irq_evt: None,
            irq_resample_evt: None,
            bus_master: Ac97BusMaster::new(mem, audio_server),
            mixer: Ac97Mixer::new(),
        }
    }

    fn create_cras_audio_device(params: Ac97Parameters, mem: GuestMemory) -> Result<Ac97Dev> {
        let mut server =
            Box::new(CrasClient::new().map_err(|e| pci_device::Error::CreateCrasClientFailed(e))?);
        if params.capture {
            server.enable_cras_capture();
        }

        let mut cras_audio = Ac97Dev::new(mem, server);
        cras_audio.set_capture_effects(params.capture_effects);
        Ok(cras_audio)
    }

    fn create_null_audio_device(mem: GuestMemory) -> Result<Ac97Dev> {
        let server = Box::new(NullShmStreamSource::new());
        let null_audio = Ac97Dev::new(mem, server);
        Ok(null_audio)
    }

    /// Creates an 'Ac97Dev' with suitable audio server inside based on Ac97Parameters
    pub fn try_new(mem: GuestMemory, param: Ac97Parameters) -> Result<Ac97Dev> {
        match param.backend {
            Ac97Backend::CRAS => Ac97Dev::create_cras_audio_device(param, mem),
            Ac97Backend::NULL => Ac97Dev::create_null_audio_device(mem),
        }
    }

    /// Provides the effect needed in capture stream creation
    pub fn set_capture_effects(&mut self, effect: Vec<StreamEffect>) {
        self.bus_master.set_capture_effects(effect);
    }

    fn read_mixer(&mut self, offset: u64, data: &mut [u8]) {
        match data.len() {
            // The mixer is only accessed with 16-bit words.
            2 => {
                let val: u16 = self.mixer.readw(offset);
                data[0] = val as u8;
                data[1] = (val >> 8) as u8;
            }
            l => error!("mixer read length of {}", l),
        }
    }

    fn write_mixer(&mut self, offset: u64, data: &[u8]) {
        match data.len() {
            // The mixer is only accessed with 16-bit words.
            2 => self
                .mixer
                .writew(offset, u16::from(data[0]) | u16::from(data[1]) << 8),
            l => error!("mixer write length of {}", l),
        }
        // Apply the new mixer settings to the bus master.
        self.bus_master.update_mixer_settings(&self.mixer);
    }

    fn read_bus_master(&mut self, offset: u64, data: &mut [u8]) {
        match data.len() {
            1 => data[0] = self.bus_master.readb(offset),
            2 => {
                let val: u16 = self.bus_master.readw(offset);
                data[0] = val as u8;
                data[1] = (val >> 8) as u8;
            }
            4 => {
                let val: u32 = self.bus_master.readl(offset);
                data[0] = val as u8;
                data[1] = (val >> 8) as u8;
                data[2] = (val >> 16) as u8;
                data[3] = (val >> 24) as u8;
            }
            l => error!("read length of {}", l),
        }
    }

    fn write_bus_master(&mut self, offset: u64, data: &[u8]) {
        match data.len() {
            1 => self.bus_master.writeb(offset, data[0], &self.mixer),
            2 => self
                .bus_master
                .writew(offset, u16::from(data[0]) | u16::from(data[1]) << 8),
            4 => self.bus_master.writel(
                offset,
                (u32::from(data[0]))
                    | (u32::from(data[1]) << 8)
                    | (u32::from(data[2]) << 16)
                    | (u32::from(data[3]) << 24),
            ),
            l => error!("write length of {}", l),
        }
    }
}

impl PciDevice for Ac97Dev {
    fn debug_label(&self) -> String {
        "AC97".to_owned()
    }

    fn assign_bus_dev(&mut self, bus: u8, device: u8) {
        self.pci_bus_dev = Some((bus, device));
    }

    fn assign_irq(
        &mut self,
        irq_evt: EventFd,
        irq_resample_evt: EventFd,
        irq_num: u32,
        irq_pin: PciInterruptPin,
    ) {
        self.config_regs.set_irq(irq_num as u8, irq_pin);
        self.irq_evt = Some(irq_evt);
        self.irq_resample_evt = Some(irq_resample_evt);
    }

    fn allocate_io_bars(&mut self, resources: &mut SystemAllocator) -> Result<Vec<(u64, u64)>> {
        let (bus, dev) = self
            .pci_bus_dev
            .expect("assign_bus_dev must be called prior to allocate_io_bars");
        let mut ranges = Vec::new();
        let mixer_regs_addr = resources
            .mmio_allocator(MmioType::Low)
            .allocate_with_align(
                MIXER_REGS_SIZE,
                Alloc::PciBar { bus, dev, bar: 0 },
                "ac97-mixer_regs".to_string(),
                MIXER_REGS_SIZE,
            )
            .map_err(|e| pci_device::Error::IoAllocationFailed(MIXER_REGS_SIZE, e))?;
        let mixer_config = PciBarConfiguration::default()
            .set_register_index(0)
            .set_address(mixer_regs_addr)
            .set_size(MIXER_REGS_SIZE);
        self.config_regs
            .add_pci_bar(&mixer_config)
            .map_err(|e| pci_device::Error::IoRegistrationFailed(mixer_regs_addr, e))?;
        ranges.push((mixer_regs_addr, MIXER_REGS_SIZE));

        let master_regs_addr = resources
            .mmio_allocator(MmioType::Low)
            .allocate_with_align(
                MASTER_REGS_SIZE,
                Alloc::PciBar { bus, dev, bar: 1 },
                "ac97-master_regs".to_string(),
                MASTER_REGS_SIZE,
            )
            .map_err(|e| pci_device::Error::IoAllocationFailed(MASTER_REGS_SIZE, e))?;
        let master_config = PciBarConfiguration::default()
            .set_register_index(1)
            .set_address(master_regs_addr)
            .set_size(MASTER_REGS_SIZE);
        self.config_regs
            .add_pci_bar(&master_config)
            .map_err(|e| pci_device::Error::IoRegistrationFailed(master_regs_addr, e))?;
        ranges.push((master_regs_addr, MASTER_REGS_SIZE));
        Ok(ranges)
    }

    fn read_config_register(&self, reg_idx: usize) -> u32 {
        self.config_regs.read_reg(reg_idx)
    }

    fn write_config_register(&mut self, reg_idx: usize, offset: u64, data: &[u8]) {
        (&mut self.config_regs).write_reg(reg_idx, offset, data)
    }

    fn keep_fds(&self) -> Vec<RawFd> {
        if let Some(server_fds) = self.bus_master.keep_fds() {
            server_fds
        } else {
            Vec::new()
        }
    }

    fn read_bar(&mut self, addr: u64, data: &mut [u8]) {
        let bar0 = self.config_regs.get_bar_addr(0);
        let bar1 = self.config_regs.get_bar_addr(1);
        match addr {
            a if a >= bar0 && a < bar0 + MIXER_REGS_SIZE => self.read_mixer(addr - bar0, data),
            a if a >= bar1 && a < bar1 + MASTER_REGS_SIZE => {
                self.read_bus_master(addr - bar1, data)
            }
            _ => (),
        }
    }

    fn write_bar(&mut self, addr: u64, data: &[u8]) {
        let bar0 = self.config_regs.get_bar_addr(0);
        let bar1 = self.config_regs.get_bar_addr(1);
        match addr {
            a if a >= bar0 && a < bar0 + MIXER_REGS_SIZE => self.write_mixer(addr - bar0, data),
            a if a >= bar1 && a < bar1 + MASTER_REGS_SIZE => {
                // Check if the irq needs to be passed to the device.
                if let (Some(irq_evt), Some(irq_resample_evt)) =
                    (self.irq_evt.take(), self.irq_resample_evt.take())
                {
                    self.bus_master.set_irq_event_fd(irq_evt, irq_resample_evt);
                }
                self.write_bus_master(addr - bar1, data)
            }
            _ => (),
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use audio_streams::shm_streams::MockShmStreamSource;
    use sys_util::GuestAddress;

    #[test]
    fn create() {
        let mem = GuestMemory::new(&[(GuestAddress(0u64), 4 * 1024 * 1024)]).unwrap();
        let mut ac97_dev = Ac97Dev::new(mem, Box::new(MockShmStreamSource::new()));
        let mut allocator = SystemAllocator::builder()
            .add_io_addresses(0x1000_0000, 0x1000_0000)
            .add_low_mmio_addresses(0x2000_0000, 0x1000_0000)
            .add_high_mmio_addresses(0x3000_0000, 0x1000_0000)
            .create_allocator(5, false)
            .unwrap();
        ac97_dev.assign_bus_dev(0, 0);
        assert!(ac97_dev.allocate_io_bars(&mut allocator).is_ok());
    }
}