use crate::sys;

use acpi::{AcpiHandler, AcpiTables, PhysicalMapping};
use alloc::boxed::Box;
use aml::value::AmlValue;
use aml::{AmlContext, AmlName, DebugVerbosity, Handler};
use core::ptr::NonNull;
use x86_64::instructions::port::Port;
use x86_64::PhysAddr;

fn read_addr<T>(addr: usize) -> T where T: Copy {
    let virtual_address = sys::mem::phys_to_virt(PhysAddr::new(addr as u64));
    unsafe { *virtual_address.as_ptr::<T>() }
}

pub fn shutdown() {
    let mut pm1a_control_block = 0;
    let mut slp_typa = 0;
    let slp_len = 1 << 13;

    log!("ACPI Shutdown");
    let res = unsafe { AcpiTables::search_for_rsdp_bios(MorosAcpiHandler) };
    match res {
        Ok(acpi) => {
            if let Ok(fadt) = acpi.find_table::<acpi::fadt::Fadt>() {
                if let Ok(block) = fadt.pm1a_control_block() {
                    pm1a_control_block = block.address as u32;
                }
            }
            if let Ok(dsdt) = &acpi.dsdt() {
                let phys_addr = PhysAddr::new(dsdt.address as u64);
                let virt_addr = sys::mem::phys_to_virt(phys_addr);
                let ptr = virt_addr.as_ptr();
                let table = unsafe {
                    core::slice::from_raw_parts(ptr , dsdt.length as usize)
                };
                let handler = Box::new(MorosAmlHandler);
                let mut aml = AmlContext::new(handler, DebugVerbosity::None);
                if aml.parse_table(table).is_ok() {
                    let name = AmlName::from_str("\\_S5").unwrap();
                    let res = aml.namespace.get_by_path(&name);
                    if let Ok(AmlValue::Package(s5)) = res {
                        if let AmlValue::Integer(value) = s5[0] {
                            slp_typa = value as u16;
                        }
                    }
                } else {
                    debug!("ACPI: Could not parse AML in DSDT");
                    // FIXME: AML parsing works on QEMU and Bochs but not
                    // on VirtualBox at the moment, so we use the following
                    // hardcoded value:
                    slp_typa = (5 & 7) << 10;
                }
            } else {
                debug!("ACPI: Could not find DSDT in BIOS");
            }
        }
        Err(_e) => {
            debug!("ACPI: Could not find RDSP in BIOS");
        }
    };

    let mut port: Port<u16> = Port::new(pm1a_control_block as u16);
    unsafe {
        port.write(slp_typa | slp_len);
    }
}

#[derive(Clone)]
pub struct MorosAcpiHandler;

impl AcpiHandler for MorosAcpiHandler {
    unsafe fn map_physical_region<T>(
        &self,
        addr: usize,
        size: usize,
    ) -> PhysicalMapping<Self, T> {
        let phys_addr = PhysAddr::new(addr as u64);
        let virt_addr = sys::mem::phys_to_virt(phys_addr);
        let ptr = NonNull::new(virt_addr.as_mut_ptr()).unwrap();
        PhysicalMapping::new(addr, ptr, size, size, Self)
    }

    fn unmap_physical_region<T>(_region: &PhysicalMapping<Self, T>) {}
}

struct MorosAmlHandler;

impl Handler for MorosAmlHandler {
    fn read_u8(&self, address: usize) -> u8 {
        read_addr::<u8>(address)
    }
    fn read_u16(&self, address: usize) -> u16 {
        read_addr::<u16>(address)
    }
    fn read_u32(&self, address: usize) -> u32 {
        read_addr::<u32>(address)
    }
    fn read_u64(&self, address: usize) -> u64 {
        read_addr::<u64>(address)
    }

    fn write_u8(&mut self, _: usize, _: u8) {
        unimplemented!()
    }
    fn write_u16(&mut self, _: usize, _: u16) {
        unimplemented!()
    }
    fn write_u32(&mut self, _: usize, _: u32) {
        unimplemented!()
    }
    fn write_u64(&mut self, _: usize, _: u64) {
        unimplemented!()
    }
    fn read_io_u8(&self, _: u16) -> u8 {
        unimplemented!()
    }
    fn read_io_u16(&self, _: u16) -> u16 {
        unimplemented!()
    }
    fn read_io_u32(&self, _: u16) -> u32 {
        unimplemented!()
    }
    fn write_io_u8(&self, _: u16, _: u8) {
        unimplemented!()
    }
    fn write_io_u16(&self, _: u16, _: u16) {
        unimplemented!()
    }
    fn write_io_u32(&self, _: u16, _: u32) {
        unimplemented!()
    }
    fn read_pci_u8(&self, _: u16, _: u8, _: u8, _: u8, _: u16) -> u8 {
        unimplemented!()
    }
    fn read_pci_u16(&self, _: u16, _: u8, _: u8, _: u8, _: u16) -> u16 {
        unimplemented!()
    }
    fn read_pci_u32(&self, _: u16, _: u8, _: u8, _: u8, _: u16) -> u32 {
        unimplemented!()
    }
    fn write_pci_u8(&self, _: u16, _: u8, _: u8, _: u8, _: u16, _: u8) {
        unimplemented!()
    }
    fn write_pci_u16(&self, _: u16, _: u8, _: u8, _: u8, _: u16, _: u16) {
        unimplemented!()
    }
    fn write_pci_u32(&self, _: u16, _: u8, _: u8, _: u8, _: u16, _: u32) {
        unimplemented!()
    }
}