/**
 * @file labels.c
 * This file contains functions for label and label candidate manipulation
 */
#include "labels.h"
static int label_skyline(FT_Face face, const char *charset, label_t *label);
static struct line_pnts *box_trans_rot(struct bound_box *bb, label_point_t *p,
                                       double angle);
static void label_point_candidates(label_t *label);
static void label_line_candidates(label_t *label);
static int candidate_compare(const void *a, const void *b);
static double label_avedist(label_t *label, label_candidate_t *candidate);
static double label_flatness(label_t *label, label_candidate_t *candidate);
static double label_pointover(label_t *label, label_candidate_t *candidate);
static double label_lineover(label_t *label, label_candidate_t *candidate,
                             int linetype);
static double min_dist_2_lines(struct line_pnts *skyline,
                               struct line_pnts *swathline, label_point_t *p);
static int box_overlap(struct bound_box *a, struct bound_box *b);
static int box_overlap2(struct line_pnts *a, struct line_pnts *b);

/**
 * The font size in map units. A global variable because I'm lazy :P
 */
static double font_size = 0.0;

/**
 * The ideal distance, that is the distance between the base line of a label and
 * a line feature.
 */
static double ideal_distance;

/**The vector Map structure*/
static struct Map_info Map;

/**
 * The size of the buffer around features where labels should never be
 */
static double buffer = 0.0;

label_t *labels_init(struct params *p, int *n_labels)
{
    label_t *labels;
    int legal_types, layer, error, sql_len;
    unsigned int i = 0;
    size_t label_sz;
    struct field_info *fi;
    dbDriver *driver;
    FT_Library library;
    FT_Face face;
    struct GFONT_CAP *font_cap;

    fprintf(stderr, "Initialising labels...");
    legal_types = Vect_option_to_types(p->type);

    /* open vector for read only */
    if (Vect_open_old(&Map, p->map->answer, "") < 0)
        G_fatal_error(_("Unable to open vector map <%s>"), p->map->answer);

    label_sz = Vect_get_num_primitives(&Map, legal_types);

    G_debug(1, "Need to allocate %lu bytes of memory",
            sizeof(label_t) * label_sz);
    labels = (label_t *)G_malloc(sizeof(label_t) * label_sz);
    G_debug(1, "labels=%p", (void *)labels);

    if (labels == NULL)
        G_fatal_error(_("Cannot allocate %lu bytes of memory"),
                      sizeof(label_t) * label_sz);

    /* open database */
    layer = atoi(p->layer->answer);
    fi = Vect_get_field(&Map, layer);
    if (fi == NULL)
        G_fatal_error(_("Unable to get layer info for vector map"));
    driver = db_start_driver_open_database(fi->driver, fi->database);
    if (driver == NULL)
        G_fatal_error(_("Unable to open database <%s> by driver <%s>"),
                      fi->database, fi->driver);
    db_set_error_handler_driver(driver);

    sql_len =
        strlen(p->column->answer) + strlen(fi->table) + strlen(fi->key) + 30;

    /* initialize FT 2 library */
    if (FT_Init_FreeType(&library))
        G_fatal_error(_("Unable to initialise FreeType"));
    font_cap = find_font_from_freetypecap(p->font->answer);
    if (font_cap == NULL)
        G_fatal_error(_("Unable to find font '%s'\n"), p->font->answer);
    if (font_cap->type != GFONT_FREETYPE)
        G_fatal_error(_("Font '%s' is not a FreeType font\n"), p->font->answer);
    error = FT_New_Face(library, font_cap->path, 0, &face);
    if (error == FT_Err_Unknown_File_Format)
        G_fatal_error(_("Font file format is not supported by FreeType"));
    else if (error)
        G_fatal_error(_("Font file can not be loaded"));
    p->font->answer = G_store(font_cap->name);
    free_freetypecap(font_cap);

    font_size = atof(p->size->answer);
    buffer = atof(p->isize->answer);

    /* use 1 point = 1 map unit */
    if (FT_Set_Char_Size(face, (int)((font_size) * 64.0), 0, 100, 100))
        G_fatal_error(_("Unable to set font size"));

    /* start reading the map */
    while (1) {
        struct line_pnts *Points;
        struct line_cats *Cats;

        dbCursor cursor;
        dbTable *table;
        dbColumn *column;
        dbString query, value;

        int type, cat, more, nrows;
        char *sql;

        if (i == label_sz) { /* we need more memory */
            label_sz += 100;
            G_debug(1, "Need to resize %p to %lu bytes of memory",
                    (void *)labels, sizeof(label_t) * label_sz);
            labels = G_realloc(labels, sizeof(label_t) * label_sz);
            if (labels == NULL) {
                G_fatal_error(_("Cannot allocate more memory"));
            }
        }

        G_percent(i, label_sz, 10);

        memset(&labels[i], 0, sizeof(label_t));

        Points = Vect_new_line_struct();
        Cats = Vect_new_cats_struct();

        type = Vect_read_next_line(&Map, Points, Cats);
        if (type == -1)
            G_fatal_error(_("Unable to read vector map"));
        if (type == -2)
            break; /* EOF */
        if (!(legal_types & type))
            continue;

        Vect_cat_get(Cats, layer, &cat);
        if (cat < 0)
            continue; /* no cat for this field */

        sql = (char *)G_malloc(sql_len);
        /* Read label from database */
        snprintf(sql, sql_len, "select %s from %s where %s = %d",
                 p->column->answer, fi->table, fi->key, cat);
        G_debug(3, "SQL: %s", sql);
        db_init_string(&query);
        db_set_string(&query, sql);
        G_free(sql);

        if (db_open_select_cursor(driver, &query, &cursor, DB_SEQUENTIAL) !=
            DB_OK)
            G_fatal_error(_("Unable to select attributes"));
        db_free_string(&query);
        nrows = db_get_num_rows(&cursor);
        if (nrows < 1) {
            G_warning(_("No record for category %d in table <%s>"), cat,
                      fi->table);
            continue;
        }

        if (db_fetch(&cursor, DB_NEXT, &more) != DB_OK || !more)
            continue;

        table = db_get_cursor_table(&cursor);
        column = db_get_table_column(table, 0); /* first column */

        db_init_string(&value);
        db_convert_column_value_to_string(column, &value);
        db_close_cursor(&cursor);

        G_debug(3, "Label: %s", db_get_string(&value));

        /* ignore empty strings */
        if (strlen(db_get_string(&value)) == 0)
            continue;

        labels[i].text = G_store(db_get_string(&value));
        labels[i].cat = cat;
        labels[i].type = type;
        labels[i].shape = Points;
        G_debug(3, "Label [%d]: %s, cat=%d, type=0x%02x", i, labels[i].text,
                labels[i].cat, labels[i].type);

        /* make a skyline for the text */
        label_skyline(face, p->charset->answer, &labels[i]);

        i++;

        db_free_string(&value);
        /*              Vect_destroy_line_struct(Points); */
        Vect_destroy_cats_struct(Cats);
    }

    {
        FT_UInt glyph_index;

        glyph_index = FT_Get_Char_Index(face, 'X');
        if (FT_Load_Glyph(face, glyph_index, FT_LOAD_DEFAULT))
            G_fatal_error("Cannot determine ideal height");
        ideal_distance = 0.3 * face->glyph->metrics.height / 64.0;
    }

    FT_Done_Face(face);
    FT_Done_FreeType(library);
    db_close_database_shutdown_driver(driver);
    /*      Vect_close(&Map); */
    G_percent(label_sz, label_sz, 10);

    *n_labels = i;
    Vect_destroy_field_info(fi);
    return labels;
}

/**
 * This function calculates the skyline of a label and stores it in the label
 * structure.
 * @param face The opened FT library face to use.
 * @param The charset to use [unused]
 * @param The label to which we want to create a skyline
 */
static int label_skyline(FT_Face face, const char *charset G_UNUSED,
                         label_t *label)
{
    int i, len;
    double advance = 0.0;

    len = strlen(label->text);
    label->skyline = Vect_new_line_struct();
    G_debug(3, "Creating skyline for '%s'", label->text);

    for (i = 0; i < len; i++) {
        FT_UInt glyph_index;

        glyph_index = FT_Get_Char_Index(face, label->text[i]);
        if (FT_Load_Glyph(face, glyph_index, FT_LOAD_DEFAULT))
            G_warning(_("Cannot load glyph for '%c'"), label->text[i]);

        /* insert the 4 corners of the bounding box */
        {
            label_point_t top_left, top_right, bottom_right, bottom_left;

            G_debug(5,
                    "horiBearingX=%ld horiBearingY=%ld width=%ld height=%ld "
                    "advance=%ld",
                    face->glyph->metrics.horiBearingX,
                    face->glyph->metrics.horiBearingY,
                    face->glyph->metrics.width, face->glyph->metrics.height,
                    face->glyph->metrics.horiAdvance);

            top_left.x = advance;
            top_left.y = face->glyph->metrics.horiBearingY / 64.0;

            top_right.x = advance + face->glyph->metrics.horiAdvance / 64.0;
            top_right.y = face->glyph->metrics.horiBearingY / 64.0;

            bottom_right.x = advance + face->glyph->metrics.horiAdvance / 64.0;
            bottom_right.y = (face->glyph->metrics.horiBearingY -
                              face->glyph->metrics.height) /
                             64.0;

            bottom_left.x = advance;
            bottom_left.y = (face->glyph->metrics.horiBearingY -
                             face->glyph->metrics.height) /
                            64.0;

            if (i == 0) {
                G_debug(5, "Character(%d) '%c': Adding UL point (%lf,%lf)", i,
                        label->text[i], top_left.x, top_left.y);
                Vect_append_point(label->skyline, top_left.x, top_left.y, 0.0);
                G_debug(5, "Character(%d) '%c': Adding UR point (%lf,%lf)", i,
                        label->text[i], top_right.x, top_right.y);
                Vect_append_point(label->skyline, top_right.x, top_right.y,
                                  0.0);

                G_debug(5, "Character(%d) '%c': Adding LR point (%lf,%lf)", i,
                        label->text[i], bottom_right.x, bottom_right.y);
                Vect_append_point(label->skyline, bottom_right.x,
                                  bottom_right.y, 0.0);

                G_debug(5, "Character(%d) '%c': Adding LL point (%lf,%lf)", i,
                        label->text[i], bottom_left.x, bottom_left.y);
                Vect_append_point(label->skyline, bottom_left.x, bottom_left.y,
                                  0.0);
                Vect_append_point(label->skyline, top_left.x, top_left.y, 0.0);
            }
            else {
                G_debug(5, "Character(%d) '%c': Adding UL point (%lf,%lf)", i,
                        label->text[i], top_left.x, top_left.y);
                Vect_line_insert_point(label->skyline, i * 2, top_left.x,
                                       top_left.y, 0.0);
                G_debug(5, "Character(%d) '%c': Adding UR point (%lf,%lf)", i,
                        label->text[i], top_right.x, top_right.y);
                Vect_line_insert_point(label->skyline, i * 2 + 1, top_right.x,
                                       top_right.y, 0.0);

                G_debug(5, "Character(%d) '%c': Adding LR point (%lf,%lf)", i,
                        label->text[i], bottom_right.x, bottom_right.y);
                Vect_line_insert_point(label->skyline, i * 2 + 2,
                                       bottom_right.x, bottom_right.y, 0.0);

                G_debug(5, "Character(%d) '%c': Adding LL point (%lf,%lf)", i,
                        label->text[i], bottom_left.x, bottom_left.y);
                Vect_line_insert_point(label->skyline, i * 2 + 3, bottom_left.x,
                                       bottom_left.y, 0.0);
            }

            advance += face->glyph->metrics.horiAdvance / 64.0;
            G_debug(5, "Total advance  %lf", advance);
        }
    }
    /* remove duplicate points */
    Vect_line_prune(label->skyline);
    /* get the boundingbox */
    Vect_line_box(label->skyline, &label->bb);
    return 1;
}

/**
 * This function generates label candidates for each label.
 * @param labels The array of labels to generate candidate places for.
 * @param n_labels The size of the array.
 */
void label_candidates(label_t *labels, int n_labels)
{
    int i;

    /* generate candidate location for each label based on feature type
     * see chapter 5 of MERL-TR-96-04 */
    fprintf(stderr, "Generating label candidates: ...");
    for (i = 0; i < n_labels; i++) {
        G_percent(i, n_labels - 1, 1);
        switch (labels[i].type) {
        case GV_POINT:
            G_debug(3, "Line (%d): %s", i, labels[i].text);
            label_point_candidates(&labels[i]);
            break;
        case GV_LINE:
            G_debug(3, "Line (%d): %s", i, labels[i].text);
            label_line_candidates(&labels[i]);
            break;
            /*                case GV_AREA:
             * label_area_candidates(labels[i]);
             * break; */
        default:
            /* this should never be reached */
            break;
        }
    }
    Vect_close(&Map);
    return;
}

/**
 * This function generates candidates for point features.
 * @param label. The point label to which we want to create label candidates.
 */
static void label_point_candidates(label_t *label)
{
    double height, width;
    int i;
    label_candidate_t *candidates;

    candidates = G_calloc(19, sizeof(label_candidate_t));
    if (candidates == NULL) {
        G_fatal_error("Cannot allocate memory.");
    }

    height = label->bb.N - label->bb.S;
    width = label->bb.E - label->bb.W;
    /* 2 upper left-hand side labels are placed so that they are
     * 1/3 and 2/3 of label height above point, and right aligned */
    candidates[0].point.x = label->shape->x[0] - width - buffer * 0.75;
    candidates[0].point.y = label->shape->y[0] + (5.0 / 9.0) * height;
    candidates[0].score = 0.63;

    candidates[1].point.x = label->shape->x[0] - width - buffer * 0.85;
    candidates[1].point.y = label->shape->y[0] + (1.0 / 3.0) * height;
    candidates[1].score = 0.44;
    /* same height as label point */
    candidates[2].point.x = label->shape->x[0] - width - buffer * 0.95;
    candidates[2].point.y = label->shape->y[0];
    candidates[2].score = 0.07;
    /* 3 lower left-hand side labels are placed so that they are
     * 1/3, 2/3 and 3/3 of label height below point, and right aligned */
    candidates[3].point.x = label->shape->x[0] - width - buffer * 0.95;
    candidates[3].point.y = label->shape->y[0] - (1.0 / 3.0) * height;
    candidates[3].score = 0.10;

    candidates[4].point.x = label->shape->x[0] - width - buffer * 0.95;
    candidates[4].point.y = label->shape->y[0] - (5.0 / 9.0) * height;
    candidates[4].score = 0.02;

    candidates[5].point.x = label->shape->x[0] - width - buffer * 0.95;
    candidates[5].point.y = label->shape->y[0] - height;
    candidates[5].score = 0.37;

    /* 2 upper right-hand side labels are placed so that they are
     * 1/3 and 2/3 of label height above point*/
    candidates[6].point.x = label->shape->x[0] + buffer * 0.85;
    candidates[6].point.y = label->shape->y[0] + (5.0 / 9.0) * height;
    candidates[6].score = 0.41;

    candidates[7].point.x = label->shape->x[0] + buffer * 0.95;
    candidates[7].point.y = label->shape->y[0] + (1.0 / 3.0) * height;
    candidates[7].score = 0.33;
    /* same height as label point */
    candidates[8].point.x = label->shape->x[0] + buffer;
    candidates[8].point.y = label->shape->y[0];
    candidates[8].score = 0.00;
    /* 4 lower left-hand side labels are placed so that they are
     * 1/4, 2/4 3/4 and 4/4 of label height below point*/
    candidates[9].point.x = label->shape->x[0] + buffer;
    candidates[9].point.y = label->shape->y[0] - 0.25 * height;
    candidates[9].score = 0.04;

    candidates[10].point.x = label->shape->x[0] + buffer;
    candidates[10].point.y = label->shape->y[0] - 0.5 * height;
    candidates[10].score = 0.3;

    candidates[11].point.x = label->shape->x[0] + buffer;
    candidates[11].point.y = label->shape->y[0] - 0.75 * height;
    candidates[11].score = 0.12;

    candidates[12].point.x = label->shape->x[0] + buffer;
    candidates[12].point.y = label->shape->y[0] - height;
    candidates[12].score = 0.59;

    /* 3 labels above, centered, centered on left 1/3 and centered
     * on right 1/3 of the label */
    candidates[13].point.x = label->shape->x[0] - (1.0 / 3.0) * width;
    candidates[13].point.y = label->shape->y[0] + fabs(label->bb.S) + buffer;
    candidates[13].score = 0.70;

    candidates[14].point.x = label->shape->x[0] - 0.5 * width;
    candidates[14].point.y = label->shape->y[0] + fabs(label->bb.S) + buffer;
    candidates[14].score = 0.89;

    candidates[15].point.x = label->shape->x[0] - (2.0 / 3.0) * width;
    candidates[15].point.y = label->shape->y[0] + fabs(label->bb.S) + buffer;
    candidates[15].score = 0.74;

    /* 3 labels below, centered, centered on left 1/3 and centered
     * on right 1/3 of the label */
    candidates[16].point.x = label->shape->x[0] - (1.0 / 3.0) * width;
    candidates[16].point.y = label->shape->y[0] - height - buffer;
    candidates[16].score = 0.74;

    candidates[17].point.x = label->shape->x[0] - 0.5 * width;
    candidates[17].point.y = label->shape->y[0] - height - buffer;
    candidates[17].score = 0.89;

    candidates[18].point.x = label->shape->x[0] - (2.0 / 3.0) * width;
    candidates[18].point.y = label->shape->y[0] - height - buffer;
    candidates[18].score = 1.0;

    for (i = 0; i < 19; i++) {
        candidates[i].score += 10.0 * label_pointover(label, &candidates[i]);
        candidates[i].score +=
            15.0 * label_lineover(label, &candidates[i], GV_LINE);
        G_debug(5, "calling label_lineover('%s', %d)", label->text, i);
        candidates[i].score +=
            10.0 * label_lineover(label, &candidates[i], GV_BOUNDARY);
        candidates[i].rotation = 0;
    }

    /* randomly choose one candidate to be the current */
    label->current_candidate = (int)(19.0 * (rand() / (RAND_MAX + 1.0)));
    label->candidates = candidates;
    label->n_candidates = 19;
}

/**
 * This function generates label candidates for a line feature.
 * @param label The label for which to create the candidates.
 */
static void label_line_candidates(label_t *label)
{
    double height, width, inc, length, pos;
    label_candidate_t *above_candidates, *below_candidates, *candidates;
    int i, n, n_c;

    height = label->bb.N - label->bb.S;
    width = label->bb.E - label->bb.W;
    inc = width / 8.0;
    length = Vect_line_length(label->shape);

    n = (int)(length / inc);
    if (n == 0) {
        /* treat the line as a point feature */
        struct line_pnts *tmp, *tmp_shape;
        double x, y;

        tmp = Vect_new_line_struct();
        Vect_point_on_line(label->shape, length / 2.0, &x, &y, NULL, NULL,
                           NULL);
        Vect_append_point(tmp, x, y, 0);
        tmp_shape = label->shape;
        label->shape = tmp;

        label_point_candidates(label);
        label->shape = tmp_shape;
        Vect_destroy_line_struct(tmp);

        return;
    }
    above_candidates = G_calloc(n, sizeof(label_candidate_t));
    below_candidates = G_calloc(n, sizeof(label_candidate_t));
    if ((above_candidates == NULL) || (below_candidates == NULL)) {
        G_fatal_error("Cannot allocate memory.");
    }

    /* find all candidate labels */
    for (pos = width / 2.0, i = 0; pos < (length - 1.5 * width); pos += inc) {
        label_point_t p1, p2, minimum_above_distance_p,
            minimum_below_distance_p;
        int seg1, seg2, j;
        struct line_pnts *above_skyline, *below_skyline, *baseline;
        double above_distance = 0.0, below_distance = 0.0,
               minimum_above_distance = 0.0, minimum_below_distance = 0.0,
               angle;
        double flatness, centerdness;

        seg1 = Vect_point_on_line(label->shape, pos, &p1.x, &p1.y, NULL, NULL,
                                  NULL);
        seg2 = Vect_point_on_line(label->shape, pos + width, &p2.x, &p2.y, NULL,
                                  NULL, NULL);

        G_debug(1, "pos=%lf i=%d p1 at (%lf,%lf), p2 at (%lf,%lf)", pos, i,
                p1.x, p1.y, p2.x, p2.y);

        angle = atan2((p2.y - p1.y), (p2.x - p1.x));

        if ((angle > M_PI / 2) || (angle < -M_PI / 2)) {
            /* turn label around 180 degrees if it would be upside down */
            double tmp;

            tmp = p1.x;
            p1.x = p2.x;
            p2.x = tmp;

            tmp = p1.y;
            p1.y = p2.y;
            p2.y = tmp;

            if (angle < 0)
                angle += M_PI;
            else
                angle -= M_PI;
        }

        /* find the maximum above_distance and below_distance from the swath
         * "diagonal" to determine maximum deviation from a straight line
         * create the swath lines at the same time.
         */
        above_candidates[i].swathline = Vect_new_line_struct();
        below_candidates[i].swathline = Vect_new_line_struct();
        if ((above_candidates[i].swathline == NULL) ||
            (below_candidates[i].swathline == NULL))
            G_fatal_error("Cannot allocate memory!");
        Vect_append_point(above_candidates[i].swathline, p1.x, p1.y, 0);
        Vect_append_point(below_candidates[i].swathline, p1.x, p1.y, 0);

        baseline = Vect_new_line_struct();
        Vect_append_point(baseline, p1.x, p1.y, 0);
        Vect_append_point(baseline, p2.x, p2.y, 0);

        Vect_append_point(above_candidates[i].swathline, p1.x, p1.y, 0);
        Vect_append_point(below_candidates[i].swathline, p1.x, p1.y, 0);

        for (j = seg1 + 1; j < seg2; j++) {
            double x, y, d;

            Vect_line_distance(baseline, label->shape->x[j], label->shape->y[j],
                               0, 0, &x, &y, NULL, &d, NULL, NULL);
            if (label->shape->y[j] < y) {
                /* swathline is beneath the "diagonal" */
                if (d > below_distance) {
                    below_distance = d;
                }
            }
            else {
                /* swatline is above or on the "diagonal" */
                if (d > above_distance) {
                    above_distance = d;
                }
            }
            Vect_append_point(above_candidates[i].swathline, label->shape->x[j],
                              label->shape->y[j], 0);
            Vect_append_point(below_candidates[i].swathline, label->shape->x[j],
                              label->shape->y[j], 0);
        }

        Vect_append_point(above_candidates[i].swathline, p2.x, p2.y, 0);
        Vect_append_point(below_candidates[i].swathline, p2.x, p2.y, 0);
        Vect_destroy_line_struct(baseline);

        if (above_distance == 0.0) {
            above_distance = height - label->bb.N;
        }
        if (below_distance == 0.0) {
            below_distance = height - label->bb.S;
        }

        /* place a skyline at above_distance above line, and
         * below_distance + height below line */
        {
            label_point_t tp;

            tp.x = p1.x - above_distance * sin(angle);
            tp.y = p1.y + above_distance * cos(angle);
            above_skyline = skyline_trans_rot(label->skyline, &tp, angle);
            tp.x = p1.x + (below_distance + height) * sin(angle);
            tp.y = p1.y - (below_distance + height) * cos(angle);
            below_skyline = skyline_trans_rot(label->skyline, &tp, angle);
        }
        /* find minimum distance between swath line and skylines */
        minimum_above_distance =
            min_dist_2_lines(above_skyline, above_candidates[i].swathline,
                             &minimum_above_distance_p);
        minimum_below_distance =
            min_dist_2_lines(below_skyline, below_candidates[i].swathline,
                             &minimum_below_distance_p);

        /* adjust skylines so that the minimum distance is equal to the ideal
         * distance (= 0.3 * glyph height of capital X) */
        above_distance += ideal_distance - minimum_above_distance;
        below_distance += ideal_distance - minimum_below_distance;

        Vect_destroy_line_struct(above_skyline);
        Vect_destroy_line_struct(below_skyline);

        above_candidates[i].point.x = p1.x - above_distance * sin(angle);
        above_candidates[i].point.y = p1.y + above_distance * cos(angle);

        below_candidates[i].point.x =
            p1.x + (below_distance + height) * sin(angle);
        below_candidates[i].point.y =
            p1.y - (below_distance + height) * cos(angle);

        G_debug(1, "above at (%lf,%lf) below at (%lf,%lf)",
                above_candidates[i].point.x, above_candidates[i].point.y,
                below_candidates[i].point.x, below_candidates[i].point.y);

        above_candidates[i].above = 1;
        below_candidates[i].above = 0;
        above_candidates[i].rotation = angle;
        below_candidates[i].rotation = angle;

        above_candidates[i].score = 0.0;
        below_candidates[i].score = 0.0;
        /* AveDist */
        above_candidates[i].score += label_avedist(label, &above_candidates[i]);
        below_candidates[i].score += label_avedist(label, &below_candidates[i]);

        /* flatness */
        flatness = label_flatness(label, &above_candidates[i]);
        above_candidates[i].score += flatness;
        flatness = label_flatness(label, &below_candidates[i]);
        below_candidates[i].score += flatness;

        /* centerdness */
        centerdness = 3.0 * fabs(2.0 * pos / length - 1.0);
        above_candidates[i].score += centerdness;
        below_candidates[i].score += centerdness;

        /* PointOver */
        above_candidates[i].score +=
            10.0 * label_pointover(label, &above_candidates[i]);
        below_candidates[i].score +=
            10.0 * label_pointover(label, &below_candidates[i]);

        /* LineOver */
        above_candidates[i].lineover =
            15.0 * label_lineover(label, &above_candidates[i], GV_LINE);
        above_candidates[i].score += above_candidates[i].lineover;

        below_candidates[i].lineover =
            15.0 * label_lineover(label, &below_candidates[i], GV_LINE);
        below_candidates[i].score += below_candidates[i].lineover;

        /* AreaOver */
        above_candidates[i].score +=
            10.0 * label_lineover(label, &above_candidates[i], GV_BOUNDARY);
        below_candidates[i].score +=
            10.0 * label_lineover(label, &below_candidates[i], GV_BOUNDARY);

        /* aboveness */
        below_candidates[i].score += 1.25;

        i++;
    }
    n = i;

    if (n == 0) {
        /* treat the line as a point feature */
        struct line_pnts *tmp, *tmp_shape;
        double x, y;

        tmp = Vect_new_line_struct();
        Vect_point_on_line(label->shape, length / 2.0, &x, &y, NULL, NULL,
                           NULL);
        Vect_append_point(tmp, x, y, 0);
        tmp_shape = label->shape;
        label->shape = tmp;

        label_point_candidates(label);
        label->shape = tmp_shape;
        Vect_destroy_line_struct(tmp);
        G_free(above_candidates);
        G_free(below_candidates);
        return;
    }

    candidates = G_calloc(n * 2, sizeof(label_candidate_t));
    for (i = 0; i < n; i++) {
        memcpy(&candidates[i * 2], &above_candidates[i],
               sizeof(label_candidate_t));
        memcpy(&candidates[i * 2 + 1], &below_candidates[i],
               sizeof(label_candidate_t));
    }
    G_free(above_candidates);
    G_free(below_candidates);

    n_c = n * 2;
    /* pick the 32 best candidates */
    qsort(candidates, n_c, sizeof(label_candidate_t), candidate_compare);

    if (n_c > 32) {
        label_candidate_t *tmp;

        for (i = 32; i < n; i++) {
            Vect_destroy_line_struct(candidates[i].baseline);
            Vect_destroy_line_struct(candidates[i].swathline);
        }

        tmp = G_realloc(candidates, sizeof(label_candidate_t) * 32);
        if (tmp != NULL) {
            candidates = tmp;
        }
        n_c = 32;
    }
    label->current_candidate =
        (int)((double)(n_c) * (rand() / (RAND_MAX + 1.0)));
    label->candidates = candidates;
    label->n_candidates = n_c;
}

/**
 * This function compares two label candidates scores and determines which is
 * better.
 * @param a Candidate A
 * @param b Candidate B
 * @return -1 if candidate a has a lower score then candidate b. = if the
 * scores are equal, and 1 if candidate a has a higher score then candidate b.
 */
static int candidate_compare(const void *a, const void *b)
{
    const label_candidate_t *ca = a, *cb = b;

    if (ca->score < cb->score) {
        return -1;
    }
    else if (ca->score == cb->score) {
        return 0;
    }
    else {
        return 1;
    }
}

struct line_pnts *skyline_trans_rot(struct line_pnts *skyline, label_point_t *p,
                                    double angle)
{
    int i;
    struct line_pnts *Points;

    Points = Vect_new_line_struct();

    for (i = 0; i < skyline->n_points; i++) {
        double x, y;

        x = skyline->x[i] * cos(angle) - skyline->y[i] * sin(angle);
        y = skyline->x[i] * sin(angle) + skyline->y[i] * cos(angle);
        Vect_append_point(Points, x + p->x, y + p->y, 0);
    }

    return Points;
}

/**
 * This function rotates and translates the label bounding box to the
 * given point, and returns it as a polygon.
 * @param bb The bounding box to translate and rotate.
 * @param p The point to translate the bounding box to
 * @param angle The angle (in radians) to rotate the label counter-clockwise
 * @return A lint_pnts structure containing the rotated and translated
 * bounding box as a polygon.
 */
static struct line_pnts *box_trans_rot(struct bound_box *bb, label_point_t *p,
                                       double angle)
{
    struct line_pnts *Points;
    double x0, y0, x1, y1, x2, y2;

    Points = Vect_new_line_struct();

    /* Lower Left, no rotation needed */
    x0 = p->x + bb->W;
    y0 = p->y + bb->S;
    Vect_append_point(Points, x0, y0, 0);
    /* Lower Right */
    x1 = (bb->E - bb->W) * cos(angle);
    y1 = (bb->E - bb->W) * sin(angle);
    Vect_append_point(Points, x0 + x1, y0 + y1, 0);

    /* Upper Right */
    x2 = (bb->N - bb->S) * sin(angle);
    y2 = (bb->N - bb->S) * cos(angle);
    /* First translate to LR, and then translate like UL */
    Vect_append_point(Points, x0 + x1 - x2, y0 + y1 + y2, 0);

    /* Upper Left */
    Vect_append_point(Points, x0 - x2, y0 + y2, 0);

    /* close polygon */
    Vect_append_point(Points, x0, y0, 0);

    return Points;
}

/**
 * This function calculates the AveDist metric for line label candidates
 * @param label The label to which candidate belongs to.
 * @candidate The candidate of which we are to calculate the metric.
 * @return The metric;
 */
static double label_avedist(label_t *label, label_candidate_t *candidate)
{
    struct line_pnts *trsk;
    double avedist = 0.0;
    int i;

    G_debug(3, "Candidate point is: (%lf,%lf)", candidate->point.x,
            candidate->point.y);
    trsk = skyline_trans_rot(label->skyline, &candidate->point,
                             candidate->rotation);

    for (i = 0; i < trsk->n_points; i++) {
        double d;

        Vect_line_distance(candidate->swathline, trsk->x[i], trsk->y[i], 0, 0,
                           NULL, NULL, NULL, &d, NULL, NULL);
        avedist += d;
    }

    for (i = 0; i < candidate->swathline->n_points; i++) {
        double d;

        Vect_line_distance(trsk, candidate->swathline->x[i],
                           candidate->swathline->y[i], 0, 0, NULL, NULL, NULL,
                           &d, NULL, NULL);
        avedist += d;
    }

    avedist /= (candidate->swathline->n_points + trsk->n_points);
    Vect_destroy_line_struct(trsk);

    return ((avedist - ideal_distance) * (avedist - ideal_distance)) /
           (ideal_distance * ideal_distance);
}

/**
 * This function calculates the Flatness metric for line label candidates
 * @param label The label to which candidate belongs to.
 * @candidate The candidate of which we are to calculate the metric.
 * @return The metric;
 */
static double label_flatness(label_t *label, label_candidate_t *candidate)
{
    struct line_pnts *line;
    double flatness = 0.0, x0, y0, x1, y1, x2, y2;
    int i;

    /* first generate a line which is parallel to the baseline,
       but the ideal distance away from it, and is between the label and the
       base line */
    line = Vect_new_line_struct();
    if (candidate->above) {
        x0 = x1 =
            candidate->point.x + ideal_distance * sin(candidate->rotation);
        y0 = y1 =
            candidate->point.y - ideal_distance * cos(candidate->rotation);
    }
    else {
        x0 = x1 =
            candidate->point.x - ideal_distance * sin(candidate->rotation);
        y0 = y1 =
            candidate->point.y + ideal_distance * cos(candidate->rotation);
    }

    Vect_append_point(line, x1, y1, 0);
    x2 = x1 + (label->bb.E - label->bb.W) * sin(candidate->rotation);
    y2 = y1 + (label->bb.E - label->bb.W) * cos(candidate->rotation);
    Vect_append_point(line, x2, y2, 0);

    /* now calculate the are between candidate->swathline and line */

    for (i = 1; i < candidate->swathline->n_points; i++) {
        int r;
        double b, h;
        double px1, py1, pz1, px2, py2, pz2;

        r = Vect_segment_intersection(
            x1, y1, 0, x2, y2, 0, candidate->swathline->x[i - 1],
            candidate->swathline->y[i - 1], 0, candidate->swathline->x[i],
            candidate->swathline->y[i], 0, &px1, &py1, &pz1, &px2, &py2, &pz2,
            0);
        /* Now calculate the area between the swath and the line */
        switch (r) {
        case 0: /* no intersection */
            dig_distance2_point_to_line(
                candidate->swathline->x[i], candidate->swathline->y[i], 0, x1,
                y1, 0, x2, y2, 0, 0, &px1, &py1, &pz1, &h, NULL);
            h = (sqrt(pow(x1 - candidate->swathline->x[i - 1], 2.0) +
                      pow(y1 - candidate->swathline->y[i - 1], 2.0)) +
                 h) /
                2.0;
            b = sqrt(pow(px1 - x1, 2) + pow(py1 - y1, 2));
            flatness += b * h;
            x1 = px1;
            y1 = py1;
            break;
        case 1:
            h = sqrt(pow(x1 - candidate->swathline->x[i - 1], 2.0) +
                     pow(y1 - candidate->swathline->y[i - 1], 2.0));
            b = sqrt(pow(px1 - x1, 2) + pow(py1 - y1, 2));
            flatness += b * h * 0.5; /* the first triangle */
            x1 = px1;
            y1 = py1;
            dig_distance2_point_to_line(
                candidate->swathline->x[i], candidate->swathline->y[i], 0, x1,
                y1, 0, x2, y2, 0, 0, &px1, &py1, &pz1, &h, NULL);
            b = sqrt(pow(px1 - x1, 2) + pow(py1 - y1, 2));
            flatness += b * h * 0.5; /* the second triangle */
            x1 = px1;
            y1 = py1;
            break;
        case 3:
            x1 = px2;
            y1 = py2;
            break;
        case 5:
            x1 = px2;
            y1 = py2;
            break;
        default:
            G_fatal_error("Programming error!!\n");
            break;
        }
    }

    flatness /=
        sqrt((x2 - x0) * (x2 - x0) + (y2 - y0) * (y2 - y0)); /* this is d'' */
    flatness = (flatness * flatness) / (ideal_distance * ideal_distance);

    Vect_destroy_line_struct(line);
    return flatness;
}

/**
 * This function checks if the label candidate overlaps with a point feature.
 * And calculates the PointOver metric.
 * @param label The label whose candidate we are investigating.
 * @param candidate The label candidate we are investigating.
 * @return The unweighted raw score of the PointOver metric for this label.
 */
static double label_pointover(label_t *label, label_candidate_t *candidate)
{
    double pointover;
    struct ilist *il;
    struct line_pnts *trbb;

    il = Vect_new_list();

    /*    trsk = skyline_trans_rot(label->skyline, &candidate->point,
       candidate->rotation);
     */
    trbb = box_trans_rot(&label->bb, &candidate->point, candidate->rotation);
    Vect_select_lines_by_polygon(&Map, trbb, 0, NULL, GV_POINT, il);

    pointover = (double)il->n_values;
    Vect_destroy_list(il);

    return pointover;
}

/**
 * This function calculates the LineOver metric for a label candidate.
 * @param label The label whose candidate we are investigating.
 * @param candidate The label candidate we are investigating.
 * @return The unweighted raw score of the LineOver metric for this label.
 */
static double label_lineover(label_t *label, label_candidate_t *candidate,
                             int linetype)
{
    double lineover = 0.0;
    struct ilist *il;
    struct line_pnts *trbb;
    label_point_t b;
    int i, n;

    il = Vect_new_list();
    G_debug(5, "Candidate point is: (%lf,%lf)", candidate->point.x,
            candidate->point.y);
    /*    trsk = skyline_trans_rot(label->skyline, &candidate->point,
       candidate->rotation); */
    b.x = fabs((label->bb.E - label->bb.W) * cos(candidate->rotation));
    b.y = fabs((label->bb.E - label->bb.W) * sin(candidate->rotation));

    trbb = box_trans_rot(&label->bb, &candidate->point, candidate->rotation);
    n = Vect_select_lines_by_polygon(&Map, trbb, 0, NULL, linetype, il);

    if (n == 0) {
        Vect_destroy_list(il);
        return 0.0;
    }

    for (i = 0; i < il->n_values; i++) {
        int j, found = 0;
        struct line_pnts *line;
        label_point_t v, v1, v2;

        line = Vect_new_line_struct();
        Vect_read_line(&Map, line, NULL, il->value[i]);

        for (j = 1; j < line->n_points; j++) {
            int k;

            for (k = 1; k < trbb->n_points; k++) {
                int r;
                double x1, x2, y1, y2, z1, z2;

                r = Vect_segment_intersection(
                    trbb->x[k - 1], trbb->y[k - 1], 0, trbb->x[k], trbb->y[k],
                    0, line->x[j - 1], line->y[j - 1], 0, line->x[j],
                    line->y[j], 0, &x1, &y1, &z1, &x2, &y2, &z2, 0);
                if (r > 0) { /* intersection at one point */
                    if (found == 0) {
                        found = 1;
                        v1.x = x1;
                        v1.y = y1;
                    }
                    else {
                        found++;
                        if (r > 1) {
                            v2.x = x2;
                            v2.y = y2;
                        }
                        else {
                            v2.x = x1;
                            v2.y = y1;
                        }
                    }
                }
            }
        }
        if (found > 1) {
            double cosvb;

            v.x = fabs(v2.x - v1.x);
            v.y = fabs(v2.y - v1.y);
            cosvb = ((b.x * v.x + b.y * v.y) / (sqrt(b.x * b.x + b.y * b.y) *
                                                sqrt(v.x * v.x + v.y * v.y)));
            lineover += 1.0 + 9.0 * cosvb;
        }
        Vect_destroy_line_struct(line);
    }

    Vect_destroy_list(il);
    return lineover;
}

/**
 * This function calculates the minimum distance between a skyline and a swath
 * line.
 * @param skyline The skyline to investigate.
 * @param swathline The swath line to investigate.
 * @param p The point on the skyline which is nearest to the swath line is
 * stored in this structure.
 * @return The distance in map units.
 */
static double min_dist_2_lines(struct line_pnts *skyline,
                               struct line_pnts *swathline, label_point_t *p)
{
    int i;
    double dist = 10000000000000000.0;

    for (i = 0; i < skyline->n_points; i++) {
        double x, y, d;

        Vect_line_distance(swathline, skyline->x[i], skyline->y[i], 0, 0, &x,
                           &y, NULL, &d, NULL, NULL);
        if (d < dist) {
            dist = d;
            p->x = skyline->x[i];
            p->y = skyline->y[i];
        }
    }

    for (i = 0; i < swathline->n_points; i++) {
        double x, y, d;

        Vect_line_distance(skyline, swathline->x[i], swathline->y[i], 0, 0, &x,
                           &y, NULL, &d, NULL, NULL);
        if (d < dist) {
            dist = d;
            p->x = x;
            p->y = y;
        }
    }

    return dist;
}

/**
 * This function finds label -label overlaps.
 * @param labels The array of labels
 * @param n_labels The size of the array
 */
void label_candidate_overlap(label_t *labels, int n_labels)
{
    int i;

    fprintf(stderr, "Finding label overlap: ...");
    for (i = 0; i < n_labels; i++) {
        int j;

        for (j = 0; j < labels[i].n_candidates; j++) {
            int k;

            for (k = i + 1; k < n_labels; k++) {
                int l;

                for (l = 0; l < labels[k].n_candidates; l++) {
                    int overlap = 0;

                    if ((labels[i].candidates[j].rotation == 0) &&
                        (labels[k].candidates[l].rotation == 0)) {
                        struct bound_box a, b;

                        a.N = labels[i].bb.N + labels[i].candidates[j].point.y;
                        a.E = labels[i].bb.E + labels[i].candidates[j].point.x;
                        a.W = labels[i].bb.W + labels[i].candidates[j].point.x;
                        a.S = labels[i].bb.S + labels[i].candidates[j].point.y;

                        b.N = labels[k].bb.N + labels[k].candidates[l].point.y;
                        b.E = labels[k].bb.E + labels[k].candidates[l].point.x;
                        b.W = labels[k].bb.W + labels[k].candidates[l].point.x;
                        b.S = labels[k].bb.S + labels[k].candidates[l].point.y;
                        overlap = box_overlap(&a, &b);
                    }
                    else {
                        struct line_pnts *a = NULL, *b = NULL;

                        a = box_trans_rot(&labels[i].bb,
                                          &labels[i].candidates[j].point,
                                          labels[i].candidates[j].rotation);
                        b = box_trans_rot(&labels[k].bb,
                                          &labels[k].candidates[l].point,
                                          labels[k].candidates[l].rotation);
                        overlap = box_overlap2(a, b);
                        Vect_destroy_line_struct(a);
                        Vect_destroy_line_struct(b);
                    }
                    if (overlap) {
                        int n;
                        label_intersection_t *li;

                        n = ++(labels[i].candidates[j].n_intersections);
                        li = G_realloc(labels[i].candidates[j].intersections,
                                       n * sizeof(label_intersection_t));
                        if (li == NULL)
                            G_fatal_error("\nUnable to allocate memory\n");
                        li[n - 1].label = &labels[k];
                        li[n - 1].candidate = l;
                        if ((labels[k].current_candidate == l) &&
                            (labels[i].current_candidate == j)) {
                            labels[i].current_score += LABEL_OVERLAP_WEIGHT;
                            labels[k].current_score += LABEL_OVERLAP_WEIGHT;
                        }
                        labels[i].candidates[j].intersections = li;
                        n = ++(labels[k].candidates[l].n_intersections);
                        li = G_realloc(labels[k].candidates[l].intersections,
                                       n * sizeof(label_intersection_t));
                        if (li == NULL)
                            G_fatal_error("\nUnable to allocate memory\n");
                        li[n - 1].label = &labels[i];
                        li[n - 1].candidate = j;

                        labels[k].candidates[l].intersections = li;
                    }
                }
            }
        }
        G_percent(i, n_labels, 1);
    }
    G_percent(n_labels, n_labels, 1);
}

/**
 * This function checks if the two given boxes overlap.
 * @param a Bounding box A
 * @param b Bounding box B
 * @return returns 1 if the two boxes overlap 0 if not.
 */
static int box_overlap(struct bound_box *a, struct bound_box *b)
{
    int vert = 0, hori = 0;

    if (((a->W < b->W) && (b->W < a->E)) || ((a->W < b->E) && (b->E < a->E)))
        vert = 1;
    if (((b->W < a->W) && (a->W < b->E)) || ((b->W < a->E) && (a->E < b->E)))
        vert = 1;

    if (((a->S < b->S) && (b->S < a->N)) || ((a->S < b->N) && (b->N < a->N)))
        hori = 1;
    if (((b->S < a->S) && (a->S < b->N)) || ((b->S < a->N) && (a->N < b->N)))
        hori = 1;

    return (hori && vert);
}

/**
 * This function checks if two rotated boxes overlap. The boxes are stored
 * as polygons and the function assumes that each box has exactly 4 sides.
 * @param a Bounding box A
 * @param b Bounding box B
 * @return returns 1 if the given boxes overlap. 0 if not.
 */
static int box_overlap2(struct line_pnts *a, struct line_pnts *b)
{
    int i, r = 0;

    for (i = 0; i < (a->n_points - 1); i++) {
        int j;

        for (j = 0; j < (b->n_points - 1); j++) {
            double d[6];

            r += Vect_segment_intersection(
                a->x[i], a->y[i], 0, a->x[i + 1], a->y[i + 1], 0, b->x[j],
                b->y[j], 0, b->x[j + 1], a->y[j + 1], 0, &d[0], &d[1], &d[2],
                &d[3], &d[4], &d[5], 0);
        }
    }
    if (r > 1)
        return 1;
    else
        return 0;
}
