use nzr_api::net::cidr::CidrV4;
use nzr_virt::error::DomainError;
use nzr_virt::xml::build::DomainBuilder;
use nzr_virt::xml::{self, SerialType};
use nzr_virt::{datasize, dom, vol};
use tokio::sync::RwLock;

use super::*;
use crate::ctrl::vm::Progress;
use crate::ctx::Context;
use crate::model::{Instance, Subnet};
use log::{debug, info, warn};
use nzr_api::args;
use nzr_api::net::mac::MacAddr;
use std::sync::Arc;

const VIRT_MAC_OUI: &[u8] = &[0x02, 0xf1, 0x0f];

macro_rules! progress {
    ($task:ident, $pct:literal, $($arg:tt)*) => {{
        let mut pt = $task.write().await;
        pt.status_text = format!($($arg)*);
        pt.percentage = $pct;
    }};
}

/// Creates a new instance
pub async fn new_instance(
    ctx: Context,
    prog_task: Arc<RwLock<Progress>>,
    args: &args::NewInstance,
) -> Result<(Instance, dom::Domain), Box<dyn std::error::Error>> {
    progress!(prog_task, 0.0, "Starting...");
    // find the subnet corresponding to the interface
    let subnet = Subnet::get_by_name(&ctx, &args.subnet)
        .await
        .map_err(|er| cmd_error!("Unable to get interface: {}", er))?
        .ok_or(cmd_error!(
            "Subnet {} wasn't found in database",
            &args.subnet
        ))?;

    // bail if a domain already exists
    if let Ok(dom) = ctx.virt.conn.get_instance(&args.name).await {
        Err(cmd_error!(
            "Domain with name already exists (uuid {})",
            dom.xml().await.uuid,
        ))
    } else {
        // make sure the base image exists
        let mut base_image = ctx
            .virt
            .pools
            .baseimg
            .volume(&args.base_image)
            .await
            .map_err(|er| cmd_error!("Couldn't find base image: {}", er))?;
        progress!(prog_task, 10.0, "Generating metadata...");

        // generate a new lease with a new MAC addr
        let mac_addr = {
            let bytes = [VIRT_MAC_OUI, rand::random::<[u8; 3]>().as_ref()].concat();
            MacAddr::from_bytes(bytes)
        }
        .map_err(|er| cmd_error!("Unable to create a new MAC address: {}", er))?;

        // Get highest host addr + 1 for our new addr
        let addr = {
            let addr_num = Instance::all_in_subnet(&ctx, &subnet)
                .await?
                .into_iter()
                .max_by(|a, b| a.host_num.cmp(&b.host_num))
                .map_or(subnet.start_host, |i| i.host_num + 1);
            if addr_num > subnet.end_host || addr_num < subnet.start_host {
                Err(cmd_error!("Got invalid lease address for instance"))?;
            }
            let addr = subnet.network.make_ip(addr_num as u32)?;
            CidrV4::new(addr, subnet.network.cidr())
        };

        let lease = nzr_api::model::Lease {
            subnet: subnet.name.clone(),
            addr,
            mac_addr,
        };

        // generate cloud-init data
        let db_inst = Instance::insert(&ctx, &args.name, &subnet, lease.clone(), None).await?;

        progress!(prog_task, 30.0, "Creating instance images...");
        // create primary volume from base image
        let mut pri_vol = base_image
            .clone_vol(
                &ctx.virt.pools.primary,
                &args.name,
                datasize!((args.disk_sizes.0) GiB),
            )
            .await
            .map_err(|er| cmd_error!("Failed to clone base image: {}", er))?;

        // and, if it exists: the second volume
        let sec_vol = match args.disk_sizes.1 {
            Some(sec_size) => {
                let voldata =
                    // TODO: Fix VolType
                    xml::Volume::new(&args.name, xml::VolType::Qcow2, datasize!(sec_size GiB));
                Some(vol::Volume::create(&ctx.virt.pools.secondary, voldata, 0).await?)
            }
            None => None,
        };

        // build domain xml
        let ifname = subnet.ifname.clone();
        let devname = format!(
            "veth-{:02x}{:02x}{:02x}",
            mac_addr[3], mac_addr[4], mac_addr[5]
        );
        progress!(prog_task, 60.0, "Initializing instance...");

        let dom_xml = {
            let pri_name = &ctx.config.storage.primary_pool;
            let sec_name = &ctx.config.storage.secondary_pool;

            let mut instdata = DomainBuilder::default()
                .name(&args.name)
                .memory(datasize!((args.memory) MiB))
                .cpu_topology(1, 1, args.cores, 1)
                .net_device(|nd| {
                    nd.mac_addr(mac_addr)
                        .with_bridge(&ifname)
                        .target_dev(&devname)
                })
                .disk_device(|dsk| {
                    dsk.volume_source(pri_name, &pri_vol.name)
                        .target("vda", "virtio")
                        .qcow2()
                        .boot_order(1)
                })
                .serial_device(SerialType::Pty);

            // add desription, if provided
            instdata = match &args.description {
                Some(desc) => instdata.description(desc),
                None => instdata,
            };

            // add second volume, if provided
            match &sec_vol {
                Some(vol) => instdata.disk_device(|dsk| {
                    dsk.volume_source(sec_name, &vol.name)
                        .target("vdb", "virtio")
                        .qcow2()
                }),
                None => instdata,
            }
            .build()
        };

        let mut virt_dom = ctx.virt.conn.define_instance(dom_xml).await?;

        // not a fatal error, we can set autostart afterward
        if let Err(er) = virt_dom.autostart(true).await {
            warn!("Couldn't set autostart for domain: {}", er);
        }

        if let Err(er) = virt_dom.start().await {
            warn!("Domain defined, but couldn't be started! Error: {}", er);
        }

        // set all volumes to persistent to avoid deletion
        pri_vol.persist = true;
        if let Some(mut sec_vol) = sec_vol {
            sec_vol.persist = true;
        }
        virt_dom.persist().await;

        progress!(prog_task, 80.0, "Domain created!");
        debug!("Domain {} created!", virt_dom.xml().await.name.as_str());
        Ok((db_inst, virt_dom))
    }
}

pub async fn delete_instance(ctx: Context, name: String) -> Result<(), Box<dyn std::error::Error>> {
    let Some(inst_db) = Instance::get_by_name(&ctx, &name).await? else {
        return Err(cmd_error!("Instance {name} not found"));
    };
    let mut inst = ctx.virt.conn.get_instance(name.clone()).await?;
    inst.undefine(true).await?;
    inst_db.delete(&ctx).await?;

    Ok(())
}

pub async fn prune_instances(ctx: &Context) -> Result<(), Box<dyn std::error::Error>> {
    for entity in Instance::all(ctx).await? {
        if let Err(err) = ctx.virt.conn.get_instance(&entity.name).await {
            if err == DomainError::DomainNotFound {
                info!("Invalid domain {}, deleting", &entity.name);
                let name = entity.name.clone();
                if let Err(err) = entity.delete(ctx).await {
                    warn!("Couldn't delete {}: {}", name, err);
                }
            }
        }
    }
    Ok(())
}