use enum_iterator::IntoEnumIterator;
use std::error::Error;

use events::{Event, EventReplyType, InterceptType};
use registers::Registers;

pub mod events;
pub mod params;
pub mod registers;

bitflags! {
    pub struct Access: u32 {
        const R=0b00000001;
        const W=0b00000010;
        const X=0b00000100;
        const NIL=0b00000000;
        const RW=Self::R.bits | Self::W.bits;
        const WX=Self::W.bits | Self::X.bits;
        const RX=Self::R.bits | Self::X.bits;
        const RWX=Self::R.bits | Self::W.bits | Self::X.bits;
    }
}

///Represents the available hypervisor VMI drivers supported by libmicrovmi
#[repr(C)]
#[derive(Debug, Copy, Clone, PartialEq, IntoEnumIterator)]
pub enum DriverType {
    KVM,
    Memflow,
    VirtualBox,
    Xen,
}

// impl TryInto<DriverInitParam> for DriverInitParamFFI {
//     type Error = IntoStringError;
//
//     fn try_into(self) -> Result<DriverInitParam, Self::Error> {
//         Ok(match self {
//             DriverInitParamFFI::KVMiSocket(cstr_socket) => DriverInitParam::KVMiSocket(
//                 unsafe { CStr::from_ptr(cstr_socket) }
//                     .to_owned()
//                     .into_string()?,
//             ),
//         })
//     }
// }

pub const PAGE_SHIFT: u32 = 12;
pub const PAGE_SIZE: u32 = 4096;

pub trait Introspectable {
    /// Retrieve the number of VCPUs.
    ///
    fn get_vcpu_count(&self) -> Result<u16, Box<dyn Error>> {
        unimplemented!();
    }

    /// read the physical memory, starting from paddr, into buf
    ///
    /// # Arguments
    ///
    /// * 'paddr' - the physical address to read from
    /// * 'buf' - the data read from memory
    /// * 'bytes_read' - the number of bytes read
    ///
    fn read_physical(
        &self,
        _paddr: u64,
        _buf: &mut [u8],
        _bytes_read: &mut u64,
    ) -> Result<(), Box<dyn Error>> {
        unimplemented!();
    }

    /// Modify contents of physical memory, starting at paddr, from buf
    ///
    /// # Arguments
    ///
    /// * 'paddr' - the physical address to write into
    /// * 'buf' - the data to be written into memory
    ///
    fn write_physical(&self, _paddr: u64, _buf: &[u8]) -> Result<(), Box<dyn Error>> {
        unimplemented!();
    }

    /// Get the maximum physical address
    ///
    /// Returns maximum physical address in 64 bit unsigned integer format.
    ///
    fn get_max_physical_addr(&self) -> Result<u64, Box<dyn Error>> {
        unimplemented!();
    }

    /// Read register values
    ///
    /// # Arguments
    /// * 'vcpu' - vcpu id for which the value of registers are to be dumped as the argument
    ///
    fn read_registers(&self, _vcpu: u16) -> Result<Registers, Box<dyn Error>> {
        unimplemented!();
    }

    ///get page access
    ///
    /// # Arguments
    /// * 'paddr' - physical address of the page whose access we want to know.
    ///
    fn get_page_access(&self, _paddr: u64) -> Result<Access, Box<dyn Error>> {
        unimplemented!();
    }

    ///set page access
    ///
    /// # Arguments
    /// * 'paddr' - physical address of the page whose access we want to set
    /// * 'access' - access flags to be set on the given page
    ///
    fn set_page_access(&self, _paddr: u64, _access: Access) -> Result<(), Box<dyn Error>> {
        unimplemented!();
    }

    /// Write register values
    ///
    /// # Arguments
    /// * 'vcpu' - vcpu id for which the value of registers are to be set
    /// * 'reg' - Registers enum having values to be set
    ///
    fn write_registers(&self, _vcpu: u16, _reg: Registers) -> Result<(), Box<dyn Error>> {
        unimplemented!();
    }

    /// Used to pause the VM
    ///
    fn pause(&mut self) -> Result<(), Box<dyn Error>> {
        unimplemented!();
    }

    /// Used to resume the VM
    ///
    fn resume(&mut self) -> Result<(), Box<dyn Error>> {
        unimplemented!();
    }

    /// Used to enable/disable an event interception
    ///
    /// # Arguments
    /// * 'vcpu' - vcpu id for which we are to enable/disable intercept monitoring
    /// * 'intercept_type' - to specify event type for which to raise flag
    /// * 'enabled' - flag to specify whether to enable/disable event monitoring
    ///
    fn toggle_intercept(
        &mut self,
        _vcpu: u16,
        _intercept_type: InterceptType,
        _enabled: bool,
    ) -> Result<(), Box<dyn Error>> {
        unimplemented!();
    }

    /// Listen and return the next event, or None
    ///
    /// # Arguments
    /// * 'timeout' - Time for which it will wait for a new event
    ///
    fn listen(&mut self, _timeout: u32) -> Result<Option<Event>, Box<dyn Error>> {
        unimplemented!();
    }

    /// Send reply corresponding to the current event being popped
    ///
    /// # Arguments
    /// * 'event'
    /// * 'reply_type'
    ///
    fn reply_event(
        &mut self,
        _event: Event,
        _reply_type: EventReplyType,
    ) -> Result<(), Box<dyn Error>> {
        unimplemented!();
    }

    /// Return the concrete DriverType
    fn get_driver_type(&self) -> DriverType;
}