use std::fs::{self, File};
use std::io;
use std::os::fd::OwnedFd;
use std::os::unix::fs::PermissionsExt;
use std::process::ExitCode;

use lazaret_core::identity::{
    BootId, BundleDigest, ConfigurationFingerprint, ContainerId, CoordinatorId, DomainId,
    GenerationId, HostPath, HostPidLocator, MountId, MountIdentity, NetworkSidecarId,
    PidfsDeviceId, PidfsInodeId, PidfsProcessAuthorityV1, PidfsProcessIdentityV1,
    ProcessStartTimeTicks, SandboxId,
};
use lazaret_core::records::{
    DurableDecision, Generation, Participant, ParticipantOwnership, ParticipantRole,
    ParticipantState, PersistedHostProcessOwnership, SandboxOwnership, StateAnchorOwnership,
};
use lazaret_host_coordinator::recovery::{
    delete_runsc_container, prove_runtime_owners_absent, runtime_recovery_ownership,
};
use lazaret_linux::process::{TargetCommand, child_broker, dispatch_private_process_role};
use rustix::process::Signal;

fn main() -> ExitCode {
    let arguments = std::env::args_os().skip(1).collect::<Vec<_>>();
    if let Some(result) = dispatch_private_process_role(&arguments) {
        return exit(result);
    }
    exit(run())
}

fn exit(result: io::Result<()>) -> ExitCode {
    match result {
        Ok(()) => ExitCode::SUCCESS,
        Err(error) => {
            eprintln!("recovery process test failed: {error}");
            ExitCode::FAILURE
        }
    }
}

fn run() -> io::Result<()> {
    verify_exact_runsc_delete()?;
    verify_exact_action(None)?;
    verify_exact_action(Some(Signal::STOP))
}

fn verify_exact_runsc_delete() -> io::Result<()> {
    let tree = tempfile::tempdir()?;
    let root_path = tree.path().join("runsc");
    fs::create_dir(&root_path)?;
    fs::create_dir(root_path.join("container"))?;
    let program = tree.path().join("runsc-fixture");
    fs::write(
        &program,
        b"#!/bin/sh\nroot=${1#-root=}\n[ \"$2\" = delete ] && [ \"$3\" = --force ] && rmdir \"$root/$4\"\n",
    )?;
    fs::set_permissions(&program, fs::Permissions::from_mode(0o700))?;
    let root: OwnedFd = File::open(&root_path)?.into();
    delete_runsc_container(&root, "container", program.as_os_str()).map_err(io::Error::other)?;
    if root_path.join("container").exists() {
        return Err(io::Error::other("exact runsc container remained"));
    }
    Ok(())
}

fn verify_exact_action(signal: Option<Signal>) -> io::Result<()> {
    let state =
        child_broker().run_transient_captured(&TargetCommand::new("/bin/sleep").argument("60"))?;
    if let Some(signal) = signal {
        state.process().send_signal(signal)?;
    }
    let state = state.into_process();
    let supervisor = child_broker()
        .run_transient_captured(&TargetCommand::new("/bin/sleep").argument("60"))?
        .into_process();
    let generation = generation();
    let participants = [
        Participant::snapshot(
            generation.generation_id,
            ParticipantRole::Sandbox,
            ParticipantState::Intent,
            Some(ParticipantOwnership::Sandbox(SandboxOwnership {
                container_id: Some(ContainerId::new([6; 32])),
                runtime_root: Some(HostPath::new(b"/runtime/runsc".to_vec())),
                runtime_root_identity: Some(MountIdentity {
                    mount_id: MountId::new(7),
                    device: lazaret_core::identity::DeviceId::new(8),
                    inode: lazaret_core::identity::InodeId::new(9),
                }),
                bundle_digest: Some(BundleDigest::new([10; 32])),
                host_coordinator: PersistedHostProcessOwnership::committed(absent_process()),
                runtime_supervisor: PersistedHostProcessOwnership::staged(supervisor.identity()),
                attached_runsc: PersistedHostProcessOwnership::unassigned(),
            })),
        )
        .map_err(|_| io::Error::other("Sandbox participant is invalid"))?,
        Participant::bare_intent(generation.generation_id, ParticipantRole::PreparedLower),
        Participant::snapshot(
            generation.generation_id,
            ParticipantRole::StateAnchor,
            ParticipantState::Intent,
            Some(ParticipantOwnership::StateAnchor(StateAnchorOwnership {
                lower_artifact_id: None,
                upper_path: None,
                work_path: None,
                merged_path: None,
                daemon: PersistedHostProcessOwnership::staged(state.identity()),
                user_namespace: None,
                mount_namespace: None,
                mount: None,
            })),
        )
        .map_err(|_| io::Error::other("State Anchor participant is invalid"))?,
    ];
    let ownership =
        runtime_recovery_ownership(&participants, &generation).map_err(io::Error::other)?;
    prove_runtime_owners_absent(&ownership)?;
    child_broker().reap(state)?;
    child_broker().reap(supervisor)
}

fn absent_process() -> PidfsProcessIdentityV1 {
    PidfsProcessIdentityV1::new(
        PidfsProcessAuthorityV1 {
            boot_id: BootId::new([0xff; 16]),
            pidfs_st_dev: PidfsDeviceId::new(1),
            pidfs_st_ino: PidfsInodeId::new(2),
        },
        HostPidLocator::new(1),
        ProcessStartTimeTicks::new(3),
    )
}

fn generation() -> Generation {
    Generation {
        domain_id: DomainId::new([1; 32]),
        generation_id: GenerationId::new(1),
        configuration_fingerprint: ConfigurationFingerprint::new([2; 32]),
        coordinator_id: CoordinatorId::new([3; 32]),
        network_sidecar_id: NetworkSidecarId::new([4; 32]),
        sandbox_id: SandboxId::new([5; 32]),
        durable_decision: DurableDecision::Preparing,
    }
}