#include <math.h>

#include <grass/vector.h>
#include <grass/glocale.h>

#include "local_proto.h"

static struct line_cats *PCats;
static struct line_pnts *PPoints;
static int point_cat = 1;

static void write_line_forward(struct Map_info *, struct line_pnts *, int, int,
                               int, double, dbDriver *, struct field_info *);
static void write_line_backward(struct Map_info *, struct line_pnts *, int, int,
                                int, double, dbDriver *, struct field_info *);

void write_point(struct Map_info *Out, double x, double y, double z,
                 int line_cat, double along, dbDriver *driver,
                 struct field_info *Fi)
{
    G_debug(3, "write_point()");

    if (!PPoints) {
        PCats = Vect_new_cats_struct();
        PPoints = Vect_new_line_struct();
    }
    else {
        Vect_reset_line(PPoints);
        Vect_reset_cats(PCats);
    }

    /* Write point */
    Vect_append_point(PPoints, x, y, z);
    if (line_cat > 0) {
        Vect_cat_set(PCats, 1, line_cat);
        Vect_cat_set(PCats, 2, point_cat);
    }
    else {
        Vect_cat_set(PCats, 2, point_cat);
    }
    Vect_write_line(Out, GV_POINT, PPoints, PCats);

    /* Attributes */
    if (Fi) {
        char buf[DB_SQL_MAX];
        dbString stmt;

        db_init_string(&stmt);
        if (line_cat > 0)
            sprintf(buf, "insert into %s values ( %d, %d, %.15g )", Fi->table,
                    point_cat, line_cat, along);
        else
            sprintf(buf, "insert into %s values ( %d, %.15g )", Fi->table,
                    point_cat, along);
        db_append_string(&stmt, buf);

        if (db_execute_immediate(driver, &stmt) != DB_OK) {
            G_warning(_("Unable to insert new record: '%s'"),
                      db_get_string(&stmt));
        }
    }
    point_cat++;
}

void write_line(struct Map_info *Out, struct line_pnts *LPoints, int cat,
                int vertex, int interpolate, int reverse, double dmax,
                dbDriver *driver, struct field_info *Fi)
{
    if (reverse == 0)
        write_line_forward(Out, LPoints, cat, vertex, interpolate, dmax, driver,
                           Fi);
    else
        write_line_backward(Out, LPoints, cat, vertex, interpolate, dmax,
                            driver, Fi);
}

static void write_line_forward(struct Map_info *Out, struct line_pnts *LPoints,
                               int cat, int vertex, int interpolate,
                               double dmax, dbDriver *driver,
                               struct field_info *Fi)
{
    if (vertex != 0) { /* use line vertices */
        double along;
        int vert;

        along = 0;
        for (vert = 0; vert < LPoints->n_points; vert++) {
            G_debug(3, "vert = %d", vert);

            if (vertex == GV_NODE && (vert > 0 && vert < LPoints->n_points - 1))
                continue;
            if (vertex == GV_START && vert > 0)
                return;
            if (vertex == GV_END && vert < LPoints->n_points - 1)
                continue;

            if (vert == LPoints->n_points - 1)
                along = Vect_line_length(LPoints);
            write_point(Out, LPoints->x[vert], LPoints->y[vert],
                        LPoints->z[vert], cat, along, driver, Fi);

            if (vert < LPoints->n_points - 1) {
                double dx, dy, dz, len;

                dx = LPoints->x[vert + 1] - LPoints->x[vert];
                dy = LPoints->y[vert + 1] - LPoints->y[vert];
                dz = LPoints->z[vert + 1] - LPoints->z[vert];
                len = hypot(hypot(dx, dy), dz);

                /* interpolate segment */
                if (interpolate && vertex == GV_VERTEX) {
                    int i, n;
                    double x, y, z, dlen;

                    if (len > dmax) {
                        n = len / dmax + 1; /* number of segments */
                        dx /= n;
                        dy /= n;
                        dz /= n;
                        dlen = len / n;

                        for (i = 1; i < n; i++) {
                            x = LPoints->x[vert] + i * dx;
                            y = LPoints->y[vert] + i * dy;
                            z = LPoints->z[vert] + i * dz;

                            write_point(Out, x, y, z, cat, along + i * dlen,
                                        driver, Fi);
                        }
                    }
                }
                along += len;
            }
        }
    }
    else { /* do not use vertices */
        int i, n;
        double len, dlen, along, x, y, z;

        len = Vect_line_length(LPoints);
        n = len / dmax + 1; /* number of segments */
        dlen = len / n;     /* length of segment */

        G_debug(3, "n = %d len = %f dlen = %f", n, len, dlen);

        for (i = 0; i <= n; i++) {
            if (i > 0 && i < n) {
                along = i * dlen;
                Vect_point_on_line(LPoints, along, &x, &y, &z, NULL, NULL);
            }
            else { /* first and last vertex */
                if (i == 0) {
                    along = 0;
                    x = LPoints->x[0];
                    y = LPoints->y[0];
                    z = LPoints->z[0];
                }
                else { /* last */
                    along = len;
                    x = LPoints->x[LPoints->n_points - 1];
                    y = LPoints->y[LPoints->n_points - 1];
                    z = LPoints->z[LPoints->n_points - 1];
                }
            }
            G_debug(3, "  i = %d along = %f", i, along);
            write_point(Out, x, y, z, cat, along, driver, Fi);
        }
    }
}

static void write_line_backward(struct Map_info *Out, struct line_pnts *LPoints,
                                int cat, int vertex, int interpolate,
                                double dmax, dbDriver *driver,
                                struct field_info *Fi)
{
    if (vertex == GV_VERTEX || vertex == GV_NODE) { /* use line vertices */
        double along;
        int vert;

        along = Vect_line_length(LPoints);
        for (vert = LPoints->n_points - 1; vert >= 0; vert--) {
            G_debug(3, "vert = %d", vert);

            if (vertex == GV_VERTEX ||
                (vertex == GV_NODE &&
                 (vert == 0 || vert == LPoints->n_points - 1))) {
                if (vert == 0)
                    along = 0;
                write_point(Out, LPoints->x[vert], LPoints->y[vert],
                            LPoints->z[vert], cat, along, driver, Fi);
            }

            if (vert > 0) {
                double dx, dy, dz, len;

                dx = LPoints->x[vert - 1] - LPoints->x[vert];
                dy = LPoints->y[vert - 1] - LPoints->y[vert];
                dz = LPoints->z[vert - 1] - LPoints->z[vert];
                len = hypot(hypot(dx, dy), dz);

                /* interpolate segment */
                if (interpolate && vertex == GV_VERTEX) {
                    int i, n;
                    double x, y, z, dlen;

                    if (len > dmax) {
                        n = len / dmax + 1; /* number of segments */
                        dx /= n;
                        dy /= n;
                        dz /= n;
                        dlen = len / n;

                        for (i = 1; i < n; i++) {
                            x = LPoints->x[vert] + i * dx;
                            y = LPoints->y[vert] + i * dy;
                            z = LPoints->z[vert] + i * dz;

                            write_point(Out, x, y, z, cat, along - i * dlen,
                                        driver, Fi);
                        }
                    }
                }
                along -= len;
            }
        }
    }
    else { /* do not use vertices */
        int i, n;
        double len, dlen, along, x, y, z;

        len = Vect_line_length(LPoints);
        n = len / dmax + 1; /* number of segments */
        dlen = len / n;     /* length of segment */

        G_debug(3, "n = %d len = %f dlen = %f", n, len, dlen);

        for (i = 0; i <= n; i++) {
            if (i > 0 && i < n) {
                along = len - i * dlen;
                Vect_point_on_line(LPoints, along, &x, &y, &z, NULL, NULL);
            }
            else { /* first and last vertex */
                if (i == 0) {
                    along = len;
                    x = LPoints->x[LPoints->n_points - 1];
                    y = LPoints->y[LPoints->n_points - 1];
                    z = LPoints->z[LPoints->n_points - 1];
                }
                else { /* last */
                    along = 0;
                    x = LPoints->x[0];
                    y = LPoints->y[0];
                    z = LPoints->z[0];
                }
            }
            G_debug(3, "  i = %d along = %f", i, along);
            write_point(Out, x, y, z, cat, along, driver, Fi);
        }
    }
}
