// This file is part of the CircuitPython project: https://circuitpython.org
//
// SPDX-FileCopyrightText: Copyright (c) 2020 Scott Shawcroft for Adafruit Industries
//
// SPDX-License-Identifier: MIT

#include "shared-bindings/memorymonitor/__init__.h"
#include "shared-bindings/memorymonitor/AllocationAlarm.h"

#include "py/gc.h"
#include "py/mpstate.h"
#include "py/runtime.h"

void common_hal_memorymonitor_allocationalarm_construct(memorymonitor_allocationalarm_obj_t *self, size_t minimum_block_count) {
    self->minimum_block_count = minimum_block_count;
    self->next = NULL;
    self->previous = NULL;
}

void common_hal_memorymonitor_allocationalarm_set_ignore(memorymonitor_allocationalarm_obj_t *self, mp_int_t count) {
    self->count = count;
}

void common_hal_memorymonitor_allocationalarm_pause(memorymonitor_allocationalarm_obj_t *self) {
    // Check to make sure we aren't already paused. We can be if we're exiting from an exception we
    // caused.
    if (self->previous == NULL) {
        return;
    }
    *self->previous = self->next;
    self->next = NULL;
    self->previous = NULL;
}

void common_hal_memorymonitor_allocationalarm_resume(memorymonitor_allocationalarm_obj_t *self) {
    if (self->previous != NULL) {
        mp_raise_RuntimeError(MP_ERROR_TEXT("Already running"));
    }
    self->next = MP_STATE_VM(active_allocationalarms);
    self->previous = (memorymonitor_allocationalarm_obj_t **)&MP_STATE_VM(active_allocationalarms);
    if (self->next != NULL) {
        self->next->previous = &self->next;
    }
    MP_STATE_VM(active_allocationalarms) = self;
}

void memorymonitor_allocationalarms_allocation(size_t block_count) {
    memorymonitor_allocationalarm_obj_t *alarm = MP_OBJ_TO_PTR(MP_STATE_VM(active_allocationalarms));
    size_t alert_count = 0;
    while (alarm != NULL) {
        // Hold onto next in case we remove the alarm from the list.
        memorymonitor_allocationalarm_obj_t *next = alarm->next;
        if (block_count >= alarm->minimum_block_count) {
            if (alarm->count > 0) {
                alarm->count--;
            } else {
                // Uncomment the breakpoint below if you want to use a C debugger to figure out the C
                // call stack for an allocation.
                // asm("bkpt");
                // Pause now because we may alert when throwing the exception too.
                common_hal_memorymonitor_allocationalarm_pause(alarm);
                alert_count++;
            }
        }
        alarm = next;
    }
    if (alert_count > 0) {
        mp_raise_memorymonitor_AllocationError(MP_ERROR_TEXT("Attempt to allocate %d blocks"), block_count);
    }
}

void memorymonitor_allocationalarms_reset(void) {
    MP_STATE_VM(active_allocationalarms) = NULL;
}