// SPDX-License-Identifier: Apache-2.0

#include <Tactility/Device.h>
#include <Tactility/Error.h>
#include <Tactility/Driver.h>
#include <Tactility/Log.h>

#include <ranges>
#include <cassert>
#include <cstring>
#include <sys/errno.h>
#include <vector>

#define TAG LOG_TAG(device)

struct DeviceData {
    std::vector<Device*> children;
};

struct DeviceLedger {
    std::vector<Device*> devices;
    Mutex mutex { 0 };

    DeviceLedger() {
        mutex_construct(&mutex);
    }

    ~DeviceLedger() {
        mutex_destruct(&mutex);
    }
};

static DeviceLedger& get_ledger() {
    static DeviceLedger ledger;
    return ledger;
}

#define ledger get_ledger()

extern "C" {

#define ledger_lock() mutex_lock(&ledger.mutex)
#define ledger_unlock() mutex_unlock(&ledger.mutex)

#define get_device_data(device) static_cast<DeviceData*>(device->internal.data)

int device_construct(Device* device) {
    device->internal.data = new(std::nothrow) DeviceData;
    if (device->internal.data == nullptr) {
        return ENOMEM;
    }
    LOG_I(TAG, "construct %s", device->name);
    mutex_construct(&device->internal.mutex);
    return 0;
}

int device_destruct(Device* device) {
    if (device->internal.state.started || device->internal.state.added) {
        return ERROR_INVALID_STATE;
    }
    if (!get_device_data(device)->children.empty()) {
        return ERROR_INVALID_STATE;
    }
    LOG_I(TAG, "destruct %s", device->name);
    mutex_destruct(&device->internal.mutex);
    delete get_device_data(device);
    device->internal.data = nullptr;
    return 0;
}

/** Add a child to the list of children */
static void device_add_child(struct Device* device, struct Device* child) {
    device_lock(device);
    assert(device->internal.state.added);
    get_device_data(device)->children.push_back(child);
    device_unlock(device);
}

/** Remove a child from the list of children */
static void device_remove_child(struct Device* device, struct Device* child) {
    device_lock(device);
    auto* parent_data = get_device_data(device);
    const auto iterator = std::ranges::find(parent_data->children, child);
    if (iterator != parent_data->children.end()) {
        parent_data->children.erase(iterator);
    }
    device_unlock(device);
}

int device_add(Device* device) {
    LOG_I(TAG, "add %s", device->name);

    // Already added
    if (device->internal.state.started || device->internal.state.added) {
        return ERROR_INVALID_STATE;
    }

    // Add to ledger
    ledger_lock();
    ledger.devices.push_back(device);
    ledger_unlock();

    // Add self to parent's children list
    auto* parent = device->parent;
    if (parent != nullptr) {
        device_add_child(parent, device);
    }

    device->internal.state.added = true;
    return 0;
}

int device_remove(Device* device) {
    LOG_I(TAG, "remove %s", device->name);

    if (device->internal.state.started || !device->internal.state.added) {
        return ERROR_INVALID_STATE;
    }

    // Remove self from parent's children list
    auto* parent = device->parent;
    if (parent != nullptr) {
        device_remove_child(parent, device);
    }

    ledger_lock();
    const auto iterator = std::ranges::find(ledger.devices, device);
    if (iterator == ledger.devices.end()) {
        ledger_unlock();
        goto failed_ledger_lookup;
    }
    ledger.devices.erase(iterator);
    ledger_unlock();

    device->internal.state.added = false;
    return 0;

failed_ledger_lookup:

    // Re-add to parent
    if (parent != nullptr) {
        device_add_child(parent, device);
    }

    return ERROR_NOT_FOUND;
}

int device_start(Device* device) {
    if (!device->internal.state.added) {
        return ERROR_INVALID_STATE;
    }

    if (device->internal.driver == nullptr) {
        return ERROR_INVALID_STATE;
    }

    // Already started
    if (device->internal.state.started) {
        return 0;
    }

    int result = driver_bind(device->internal.driver, device);
    device->internal.state.started = (result == 0);
    device->internal.state.start_result = result;
    return result;
}

int device_stop(struct Device* device) {
    if (!device->internal.state.added) {
        return ERROR_INVALID_STATE;
    }

    // Not started
    if (!device->internal.state.started) {
        return 0;
    }

    int result = driver_unbind(device->internal.driver, device);
    if (result != 0) {
        return result;
    }

    device->internal.state.started = false;
    device->internal.state.start_result = 0;
    return 0;
}

void device_set_parent(Device* device, Device* parent) {
    assert(!device->internal.state.started);
    device->parent = parent;
}

void for_each_device(void* callback_context, bool(*on_device)(Device* device, void* context)) {
    ledger_lock();
    for (auto* device : ledger.devices) {
        if (!on_device(device, callback_context)) {
            break;
        }
    }
    ledger_unlock();
}

void for_each_device_child(Device* device, void* callback_context, bool(*on_device)(struct Device* device, void* context)) {
    auto* data = get_device_data(device);
    for (auto* child_device : data->children) {
        if (!on_device(child_device, callback_context)) {
            break;
        }
    }
}

void for_each_device_of_type(const DeviceType* type, void* callback_context, bool(*on_device)(Device* device, void* context)) {
    ledger_lock();
    for (auto* device : ledger.devices) {
        auto* driver = device->internal.driver;
        if (driver != nullptr) {
            if (driver->device_type == type) {
                if (!on_device(device, callback_context)) {
                    break;
                }
            }
        }
    }
    ledger_unlock();
}

} // extern "C"