#include "thumbnail.h"
#include <magick/api.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <string.h>

/* http://www.graphicsmagick.org/api/api.html */

int thumbnail_create(const char *const src, const char *const dst)
{
    int ret = -1;
    const size_t slen = strlen(src), dlen = strlen(dst);
    ImageInfo *info = NULL;
    Image *i = NULL, *t = NULL;
    ExceptionInfo exc;

    InitializeMagick(NULL);
    GetExceptionInfo(&exc);

    if (slen >= sizeof i->filename)
    {
        fprintf(stderr, "%s: src maximum length exceeded (%zu, max %zu)\n",
            __func__, slen, sizeof i->filename - 1);
        goto end;
    }
    else if (dlen >= sizeof t->filename)
    {
        fprintf(stderr, "%s: dst maximum length exceeded (%zu, max %zu)\n",
            __func__, slen, sizeof t->filename - 1);
        goto end;
    }
    else if (!(info = CloneImageInfo(NULL)))
    {
        fprintf(stderr, "%s: CloneImageInfo failed\n", __func__);
        goto end;
    }

    strcpy(info->filename, src);
    info->adjoin = MagickTrue;

    if (!(i = ReadImage(info, &exc)))
    {
        if (exc.severity == MissingDelegateError)
            /* Non-image file format. */
            ret = 1;
        else
            fprintf(stderr, "%s: ReadImage failed: "
                "reason: %s, description: %s\n",
                __func__, exc.reason, exc.description);

        goto end;
    }

    const unsigned long y = i->rows > THUMBNAIL_HEIGHT ?
        THUMBNAIL_HEIGHT : i->rows,
        x = y * i->columns / i->rows;

    if (!(t = ResizeImage(i, x, y, PointFilter, 1, &exc)))
    {
        fprintf(stderr, "%s: ResizeImage failed, "
            "reason: %s, description: %s\n",
            __func__, exc.reason, exc.description);
        goto end;
    }
    else if (WriteImages(info, t, dst, &exc) != MagickPass)
    {
        fprintf(stderr, "%s: WriteImages failed, "
            "reason: %s, description: %s\n",
            __func__, exc.reason, exc.description);
        goto end;
    }

    ret = 0;

end:
    DestroyImageInfo(info);
    DestroyImage(i);
    DestroyImage(t);
    DestroyExceptionInfo(&exc);
    DestroyMagick();
    return ret;
}

bool thumbnail_configured(void)
{
    return true;
}

int thumbnail_dim(const char *const path, struct thumbnail_dim *const d)
{
    int ret = -1;
    const size_t slen = strlen(path);
    ImageInfo *info = NULL;
    Image *i = NULL;
    ExceptionInfo exc;

    InitializeMagick(NULL);
    GetExceptionInfo(&exc);

    if (slen >= sizeof i->filename)
    {
        fprintf(stderr, "%s: src maximum length exceeded (%zu, max %zu)\n",
            __func__, slen, sizeof i->filename - 1);
        goto end;
    }
    else if (!(info = CloneImageInfo(NULL)))
    {
        fprintf(stderr, "%s: CloneImageInfo failed\n", __func__);
        goto end;
    }

    strcpy(info->filename, path);
    info->adjoin = MagickTrue;

    if (!(i = ReadImage(info, &exc)))
    {
        if (exc.severity == MissingDelegateError)
            /* Non-image file format. */
            ret = 1;
        else
            fprintf(stderr, "%s: ReadImage failed: "
                "reason: %s, description: %s\n",
                __func__, exc.reason, exc.description);

        goto end;
    }

    *d = (const struct thumbnail_dim)
    {
        .w = i->columns,
        .h = i->rows
    };

    ret = 0;

end:
    DestroyImageInfo(info);
    DestroyImage(i);
    DestroyExceptionInfo(&exc);
    DestroyMagick();
    return ret;
}