#include <stdlib.h>
#include <string.h>

#include "overlay.h"


int overlay_init(Overlay* overlay) {
    overlay->messages = NULL;
    overlay->next_id = 0;
    return 0;
}

void overlay_done(Overlay* overlay) {
    overlay_message* next = NULL;
    for (   overlay_message* message = overlay->messages;
            NULL != message;
            message = next) {
        next = message->next;
        free(message->string);
        free(message);
    }
}

int overlay_clear(Overlay* overlay) {
    int n_cleared = 0;
    for (   overlay_message* message = overlay->messages;
            NULL != message;
            message = message->next) {
        free(message->string);
        free(message);
        ++n_cleared;
    }
    overlay_init(overlay);
    return n_cleared;
}

int overlay_clear_message(Overlay* overlay, int id) {
    int result = -1;
    overlay_message* last = NULL;
    overlay_message* message = overlay->messages;
    for (   ;
            NULL != message && message->id != id;
            last = message, message = message->next
        );
    if (NULL != message) {
        result = 0;
        if (NULL == last) {
            overlay->messages = message->next;
        } else {
            last->next = message->next;
        }
        free(message->string);
        free(message);
    }
    return result;
}

int overlay_add_message(Overlay* overlay,
                        const char* string, int expiry) {
    overlay_message* message = calloc(1, sizeof(*message));
    message->string = strdup(string);
    message->id     = ++(overlay->next_id);
    message->expiry = expiry;
    message->next   = NULL;
    if (NULL == overlay->messages) {
        overlay->messages = message;
    } else {
        overlay_message* last = overlay->messages;
        for ( ; NULL != last->next; last = last->next);
        last->next = message;
    }
    return message->id;
}