use domain::process::MAX_THREADS_PER_PROCESS;
use platform::Platform;

use super::{SyscallOutcome, SyscallResult};
use crate::Kernel;

impl<P: Platform> Kernel<P> {
    pub(crate) fn handle_spawn_thread(
        &mut self,
        pid: types::id::ProcessId,
        entry: types::address::EntryPoint,
        stack: types::address::StackPointer,
    ) -> SyscallOutcome {
        use domain::scheduler::Scheduler;
        use domain::thread::SavedContext;

        let priority = types::bounded::Priority::DEFAULT;
        let time_slice = types::time::TimeSlice::DEFAULT;
        let context = SavedContext::with_entry_and_stack(entry, stack);

        let tid = match self.threads.spawn_with_context(pid, priority, time_slice, None, context) {
            Ok(t) => t,
            Err(e) => return SyscallOutcome::Complete(SyscallResult::Error(e)),
        };

        if let Err(e) = self.processes.get_mut(pid).and_then(|p| p.add_thread(tid)) {
            let _ = self.threads.destroy(tid);
            return SyscallOutcome::Complete(SyscallResult::Error(e));
        }

        let core = self.platform.core_id();
        self.scheduler.add(tid, priority, core);
        SyscallOutcome::Complete(SyscallResult::Value(tid.raw() as usize))
    }

    pub(crate) fn handle_create_process(
        &mut self,
        caller_pid: types::id::ProcessId,
        create_cap: types::bounded::CapSlot,
        _image: types::address::DataRef,
    ) -> SyscallOutcome {
        if let Err(e) = self.check_cap(caller_pid, create_cap, types::permission::Permission::Execute) {
            return SyscallOutcome::Complete(SyscallResult::Error(e));
        }

        let new_pid = match self.processes.create(
            domain::capability::CapabilityTable::new(),
            None,
        ) {
            Ok(p) => p,
            Err(e) => return SyscallOutcome::Complete(SyscallResult::Error(e)),
        };

        self.process_memory[new_pid.raw() as usize] =
            Some(domain::memory::process_memory::ProcessMemory::new(new_pid, domain::memory::process_memory::ProcessMemory::DEFAULT_PAGE_LIMIT));

        match self.grant_cap(
            caller_pid,
            domain::resource::Resource::Process(new_pid),
            types::permission::PermissionSet::empty()
                .with(types::permission::Permission::Execute)
                .with(types::permission::Permission::Read),
        ) {
            Ok(slot) => SyscallOutcome::Complete(SyscallResult::Slot(slot)),
            Err(e) => {
                // Rollback: destroy orphaned process
                let _ = self.processes.destroy(new_pid);
                self.process_memory[new_pid.raw() as usize] = None;
                SyscallOutcome::Complete(SyscallResult::Error(e))
            }
        }
    }

    pub(crate) fn handle_spawn_thread_in(
        &mut self,
        caller_pid: types::id::ProcessId,
        process_cap: types::bounded::CapSlot,
        entry: types::address::EntryPoint,
        stack: types::address::StackPointer,
    ) -> SyscallOutcome {
        use domain::scheduler::Scheduler;
        use domain::thread::SavedContext;

        let target_pid = match self.check_cap(
            caller_pid,
            process_cap,
            types::permission::Permission::Execute,
        ) {
            Ok(cap) => match cap.resource() {
                domain::resource::Resource::Process(pid) => *pid,
                _ => return SyscallOutcome::Complete(SyscallResult::Error(
                    domain::error::KernelError::PermissionDenied {
                        slot: process_cap,
                        needed: types::permission::Permission::Execute,
                    },
                )),
            },
            Err(e) => return SyscallOutcome::Complete(SyscallResult::Error(e)),
        };

        let priority = types::bounded::Priority::DEFAULT;
        let time_slice = types::time::TimeSlice::DEFAULT;
        let context = SavedContext::with_entry_and_stack(entry, stack);

        let tid = match self.threads.spawn_with_context(target_pid, priority, time_slice, None, context) {
            Ok(t) => t,
            Err(e) => return SyscallOutcome::Complete(SyscallResult::Error(e)),
        };

        if let Err(e) = self.processes.get_mut(target_pid).and_then(|p| p.add_thread(tid)) {
            let _ = self.threads.destroy(tid);
            return SyscallOutcome::Complete(SyscallResult::Error(e));
        }

        let core = self.platform.core_id();
        self.scheduler.add(tid, priority, core);
        SyscallOutcome::Complete(SyscallResult::Value(tid.raw() as usize))
    }

    pub(crate) fn handle_kill(
        &mut self,
        caller_pid: types::id::ProcessId,
        process_cap: types::bounded::CapSlot,
    ) -> SyscallOutcome {
        let target_pid = match self.check_cap(caller_pid, process_cap, types::permission::Permission::Execute) {
            Ok(cap) => match cap.resource() {
                domain::resource::Resource::Process(pid) => *pid,
                _ => return SyscallOutcome::Complete(SyscallResult::Error(
                    domain::error::KernelError::PermissionDenied {
                        slot: process_cap,
                        needed: types::permission::Permission::Execute,
                    },
                )),
            },
            Err(e) => return SyscallOutcome::Complete(SyscallResult::Error(e)),
        };

        self.destroy_process(target_pid);
        SyscallOutcome::Complete(SyscallResult::Ok)
    }
}