/****************************************************************************
 *
 * MODULE:       r.neighbors
 * AUTHOR(S):    Michael Shapiro, CERL (original contributor)
 *               Markus Neteler <neteler itc.it>,
 *               Bob Covill <bcovill tekmap.ns.ca>,
 *               Brad Douglas <rez touchofmadness.com>,
 *               Glynn Clements <glynn gclements.plus.com>,
 *               Jachym Cepicky <jachym les-ejk.cz>,
 *               Jan-Oliver Wagner <jan intevation.de>,
 *               Radim Blazek <radim.blazek gmail.com>,
 *               Aaron Saw Min Sern (OpenMP parallelization)
 *
 * PURPOSE:      Makes each cell category value a function of the category
 *               values assigned to the cells around it, and stores new cell
 *               values in an output raster map layer
 * COPYRIGHT:    (C) 1999-2022 by the GRASS Development Team
 *
 *               This program is free software under the GNU General Public
 *               License (>=v2). Read the file COPYING that comes with GRASS
 *               for details.
 *
 *****************************************************************************/

#if defined(_OPENMP)
#include <omp.h>
#endif

#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <grass/gis.h>
#include <grass/raster.h>
#include <grass/glocale.h>
#include <grass/stats.h>
#include "ncb.h"
#include "local_proto.h"

typedef int (*ifunc)(void);

struct menu {
    stat_func *method;     /* routine to compute new value */
    stat_func_w *method_w; /* routine to compute new value (weighted) */
    ifunc cat_names;       /* routine to make category names */
    int copycolr;          /* flag if color table can be copied */
    int half;              /* whether to add 0.5 to result (redundant) */
    int otype;             /* output type */
    char *name;            /* method name */
    char *text;            /* menu display - full description */
};

struct weight_functions {
    char *name; /* name  of the weight type */
    char *text; /* weight types display - full description */
};

enum out_type { T_FLOAT = 1, T_INT = 2, T_COUNT = 3, T_COPY = 4, T_SUM = 5 };

#define NO_CATS      0
#define FIRST_THREAD 0

/* modify this table to add new methods */
static struct menu menu[] = {
    {c_ave, w_ave, NO_CATS, 1, 1, T_FLOAT, "average", "average value"},
    {c_median, w_median, NO_CATS, 1, 0, T_FLOAT, "median", "median value"},
    {c_mode, w_mode, NO_CATS, 1, 0, T_COPY, "mode",
     "most frequently occurring value"},
    {c_min, NULL, NO_CATS, 1, 0, T_COPY, "minimum", "lowest value"},
    {c_max, NULL, NO_CATS, 1, 0, T_COPY, "maximum", "highest value"},
    {c_range, NULL, NO_CATS, 1, 0, T_COPY, "range", "range value"},
    {c_stddev, w_stddev, NO_CATS, 0, 1, T_FLOAT, "stddev",
     "standard deviation"},
    {c_sum, w_sum, NO_CATS, 1, 0, T_SUM, "sum", "sum of values"},
    {c_count, w_count, NO_CATS, 0, 0, T_COUNT, "count",
     "count of non-NULL values"},
    {c_var, w_var, NO_CATS, 0, 1, T_FLOAT, "variance", "statistical variance"},
    {c_divr, NULL, divr_cats, 0, 0, T_INT, "diversity",
     "number of different values"},
    {c_intr, NULL, intr_cats, 0, 0, T_INT, "interspersion",
     "number of values different than center value"},
    {c_quart1, w_quart1, NO_CATS, 1, 0, T_FLOAT, "quart1", "first quartile"},
    {c_quart3, w_quart3, NO_CATS, 1, 0, T_FLOAT, "quart3", "third quartile"},
    {c_perc90, w_perc90, NO_CATS, 1, 0, T_FLOAT, "perc90",
     "ninetieth percentile"},
    {c_quant, w_quant, NO_CATS, 1, 0, T_FLOAT, "quantile",
     "arbitrary quantile"},
    {0, 0, 0, 0, 0, 0, 0, 0}};

struct ncb ncb;

struct output {
    const char *name;
    char title[1024];
    int fd;
    DCELL *buf;
    stat_func *method_fn;
    stat_func_w *method_fn_w;
    int copycolr;
    ifunc cat_names;
    int map_type;
    double quantile;
};

static int find_method(const char *method_name)
{
    int i;

    for (i = 0; menu[i].name; i++)
        if (strcmp(menu[i].name, method_name) == 0)
            return i;

    G_fatal_error(_("Unknown method <%s>"), method_name);

    return -1;
}

static RASTER_MAP_TYPE output_type(RASTER_MAP_TYPE input_type, int weighted,
                                   int mode)
{
    switch (mode) {
    case T_FLOAT:
        return DCELL_TYPE;
    case T_INT:
        return CELL_TYPE;
    case T_COUNT:
        return weighted ? DCELL_TYPE : CELL_TYPE;
    case T_COPY:
        return input_type;
    case T_SUM:
        return weighted ? DCELL_TYPE : input_type;
    default:
        G_fatal_error(_("Invalid out_type enumeration: %d"), mode);
        return -1;
    }
}

int main(int argc, char *argv[])
{
    char *p;
    int *in_fd;
    int *selection_fd;
    int num_outputs;
    struct output *outputs = NULL;
    int copycolr, weights, have_weights_mask;
    char **selection;
    RASTER_MAP_TYPE map_type;
    int row, col;
    int *readrow;
    int nrows, ncols, brows;
    int i, n, t;
    size_t size, in_buf_size, out_buf_size;
    struct Colors colr;
    struct Cell_head cellhd;
    struct Cell_head window;
    struct History history;
    struct GModule *module;
    struct {
        struct Option *input, *output, *selection;
        struct Option *method, *size;
        struct Option *title;
        struct Option *weight;
        struct Option *weighting_function;
        struct Option *weighting_factor;
        struct Option *quantile;
        struct Option *nprocs;
        struct Option *memory;
    } parm;
    struct {
        struct Flag *align, *circle;
    } flag;

    DCELL **values;     /* list of neighborhood values */
    DCELL **values_tmp; /* list of neighborhood values */

    DCELL(**values_w)[2];     /* list of neighborhood values and weights */
    DCELL(**values_w_tmp)[2]; /* list of neighborhood values and weights */

    G_gisinit(argv[0]);

    module = G_define_module();
    G_add_keyword(_("raster"));
    G_add_keyword(_("algebra"));
    G_add_keyword(_("statistics"));
    G_add_keyword(_("aggregation"));
    G_add_keyword(_("neighbor"));
    G_add_keyword(_("focal statistics"));
    G_add_keyword(_("filter"));
    G_add_keyword(_("parallel"));
    module->description =
        _("Makes each cell category value a "
          "function of the category values assigned to the cells "
          "around it, and stores new cell values in an output raster "
          "map layer.");

    parm.input = G_define_standard_option(G_OPT_R_INPUT);

    parm.selection = G_define_standard_option(G_OPT_R_INPUT);
    parm.selection->key = "selection";
    parm.selection->required = NO;
    parm.selection->description = _("Name of an input raster map to select the "
                                    "cells which should be processed");

    parm.output = G_define_standard_option(G_OPT_R_OUTPUT);
    parm.output->multiple = YES;

    parm.size = G_define_option();
    parm.size->key = "size";
    parm.size->type = TYPE_INTEGER;
    parm.size->required = NO;
    parm.size->description = _("Neighborhood size");
    parm.size->answer = "3";
    parm.size->guisection = _("Neighborhood");

    parm.method = G_define_option();
    parm.method->key = "method";
    parm.method->type = TYPE_STRING;
    parm.method->required = NO;
    parm.method->answer = "average";
    p = G_malloc(1024);
    for (n = 0; menu[n].name; n++) {
        if (n)
            strcat(p, ",");
        else
            *p = 0;
        strcat(p, menu[n].name);
    }
    parm.method->options = p;
    parm.method->description = _("Neighborhood operation");
    parm.method->multiple = YES;
    parm.method->guisection = _("Neighborhood");

    parm.weighting_function = G_define_option();
    parm.weighting_function->key = "weighting_function";
    parm.weighting_function->type = TYPE_STRING;
    parm.weighting_function->required = NO;
    parm.weighting_function->answer = "none";
    parm.weighting_function->options = "none,gaussian,exponential,file";
    G_asprintf((char **)&(parm.weighting_function->descriptions),
               "none;%s;"
               "gaussian;%s;"
               "exponential;%s;"
               "file;%s;",
               _("No weighting"), _("Gaussian weighting function"),
               _("Exponential weighting function"),
               _("File with a custom weighting matrix"));
    parm.weighting_function->description = _("Weighting function");
    parm.weighting_function->multiple = NO;

    parm.weighting_factor = G_define_option();
    parm.weighting_factor->key = "weighting_factor";
    parm.weighting_factor->type = TYPE_DOUBLE;
    parm.weighting_factor->required = NO;
    parm.weighting_factor->multiple = NO;
    parm.weighting_factor->description =
        _("Factor used in the selected weighting function (ignored for none "
          "and file)");

    parm.weight = G_define_standard_option(G_OPT_F_INPUT);
    parm.weight->key = "weight";
    parm.weight->required = NO;
    parm.weight->description = _("Text file containing weights");

    parm.quantile = G_define_option();
    parm.quantile->key = "quantile";
    parm.quantile->type = TYPE_DOUBLE;
    parm.quantile->required = NO;
    parm.quantile->multiple = YES;
    parm.quantile->description = _("Quantile to calculate for method=quantile");
    parm.quantile->options = "0.0-1.0";
    parm.quantile->guisection = _("Neighborhood");

    parm.title = G_define_option();
    parm.title->key = "title";
    parm.title->key_desc = "phrase";
    parm.title->type = TYPE_STRING;
    parm.title->required = NO;
    parm.title->description = _("Title for output raster map");

    parm.nprocs = G_define_standard_option(G_OPT_M_NPROCS);
    parm.memory = G_define_standard_option(G_OPT_MEMORYMB);

    flag.align = G_define_flag();
    flag.align->key = 'a';
    flag.align->description = _("Do not align output with the input");

    flag.circle = G_define_flag();
    flag.circle->key = 'c';
    flag.circle->description = _("Use circular neighborhood");
    flag.circle->guisection = _("Neighborhood");

    if (G_parser(argc, argv))
        exit(EXIT_FAILURE);

    sscanf(parm.size->answer, "%d", &ncb.nsize);
    if (ncb.nsize <= 0)
        G_fatal_error(_("Neighborhood size must be positive"));
    if (ncb.nsize % 2 == 0)
        G_fatal_error(_("Neighborhood size must be odd"));
    ncb.dist = ncb.nsize / 2;

    sscanf(parm.nprocs->answer, "%d", &ncb.threads);
    if (ncb.threads < 1) {
        G_fatal_error(_("<%d> is not valid number of threads."), ncb.threads);
    }
#if defined(_OPENMP)
    omp_set_num_threads(ncb.threads);
#else
    if (ncb.threads != 1)
        G_warning(_("GRASS is compiled without OpenMP support. Ignoring "
                    "threads setting."));
    ncb.threads = 1;
#endif
    if (ncb.threads > 1 && G_find_raster("MASK", G_mapset()) != NULL) {
        G_warning(_("Parallel processing disabled due to active MASK."));
        ncb.threads = 1;
    }
    if (strcmp(parm.weighting_function->answer, "none") && flag.circle->answer)
        G_fatal_error(_("-%c and %s= are mutually exclusive"), flag.circle->key,
                      parm.weighting_function->answer);

    if (strcmp(parm.weighting_function->answer, "file") == 0 &&
        !parm.weight->answer)
        G_fatal_error(_("File with weighting matrix is missing."));

    /* Check if weighting factor is given for all other weighting functions */
    if (strcmp(parm.weighting_function->answer, "none") &&
        strcmp(parm.weighting_function->answer, "file") &&
        !parm.weighting_factor->answer)
        G_fatal_error(_("Weighting function '%s' requires a %s."),
                      parm.weighting_function->answer,
                      parm.weighting_factor->key);

    ncb.oldcell = parm.input->answer;

    if (!flag.align->answer) {
        Rast_get_cellhd(ncb.oldcell, "", &cellhd);
        G_get_window(&window);
        Rast_align_window(&window, &cellhd);
        Rast_set_window(&window);
    }

    nrows = Rast_window_rows();
    ncols = Rast_window_cols();

    /* open raster maps */
    in_fd = G_malloc(sizeof(int) * ncb.threads);
    for (i = 0; i < ncb.threads; i++) {
        in_fd[i] = Rast_open_old(ncb.oldcell, "");
    }
    map_type = Rast_get_map_type(in_fd[FIRST_THREAD]);

    /* process the output maps */
    for (i = 0; parm.output->answers[i]; i++)
        ;
    num_outputs = i;

    for (i = 0; parm.method->answers[i]; i++)
        ;
    if (num_outputs != i)
        G_fatal_error(_("%s= and %s= must have the same number of values"),
                      parm.output->key, parm.method->key);

    outputs = G_calloc(num_outputs, sizeof(struct output));

    /* memory reserved for input */
    in_buf_size = (Rast_window_cols() + 2 * ncb.dist) * sizeof(DCELL) *
                  ncb.nsize * ncb.threads;
    /* memory available for output buffer */
    out_buf_size = (size_t)atoi(parm.memory->answer) * (1 << 20);
    /* size_t is unsigned, check if any memory is left for output buffer */
    if (out_buf_size <= in_buf_size)
        out_buf_size = 0;
    else
        out_buf_size -= in_buf_size;
    /* number of buffered rows for all output maps */
    brows = out_buf_size / (sizeof(DCELL) * ncols * num_outputs);
    /* set the output buffer rows to be at most covering the entire map */
    if (brows > nrows) {
        brows = nrows;
    }
    /* but at least the number of threads */
    if (brows < ncb.threads) {
        brows = ncb.threads;
    }

    /* read the weights */
    weights = 0;
    ncb.weights = NULL;
    ncb.mask = NULL;
    if (strcmp(parm.weighting_function->answer, "file") == 0) {
        read_weights(parm.weight->answer);
        weights = 1;
    }
    else if (strcmp(parm.weighting_function->answer, "none")) {
        G_verbose_message(_("Computing %s weights..."),
                          parm.weighting_function->answer);
        compute_weights(parm.weighting_function->answer,
                        atof(parm.weighting_factor->answer));
        weights = 1;
    }

    copycolr = 0;
    have_weights_mask = 0;

    for (i = 0; i < num_outputs; i++) {
        struct output *out = &outputs[i];
        const char *output_name = parm.output->answers[i];
        const char *method_name = parm.method->answers[i];
        int method = find_method(method_name);
        RASTER_MAP_TYPE otype =
            output_type(map_type, weights, menu[method].otype);

        out->name = output_name;
        if (weights) {
            if (menu[method].method_w) {
                out->method_fn = NULL;
                out->method_fn_w = menu[method].method_w;
            }
            else {
                if (strcmp(parm.weighting_function->answer, "none")) {
                    G_warning(_("Method %s not compatible with weighing "
                                "window, using weight mask instead"),
                              method_name);
                    if (!have_weights_mask) {
                        weights_mask();
                        have_weights_mask = 1;
                    }
                }
                out->method_fn = menu[method].method;
                out->method_fn_w = NULL;
            }
        }
        else {
            out->method_fn = menu[method].method;
            out->method_fn_w = NULL;
        }
        out->copycolr = menu[method].copycolr;
        out->cat_names = menu[method].cat_names;
        if (out->copycolr)
            copycolr = 1;
        out->quantile = (parm.quantile->answer && parm.quantile->answers[i])
                            ? atof(parm.quantile->answers[i])
                            : 0;
        out->buf = G_malloc(sizeof(DCELL) * brows * ncols);
        out->fd = Rast_open_new(output_name, otype);
        /* TODO: method=mode should propagate its type */

        /* get title, initialize the category and stat info */
        if (parm.title->answer)
            strcpy(out->title, parm.title->answer);
        else
            sprintf(out->title, "%dx%d neighborhood: %s of %s", ncb.nsize,
                    ncb.nsize, menu[method].name, ncb.oldcell);
    }

    /* copy color table? */
    if (copycolr) {
        G_suppress_warnings(1);
        copycolr = (Rast_read_colors(ncb.oldcell, "", &colr) > 0);
        G_suppress_warnings(0);
    }

    /* allocate the cell buffers */
    allocate_bufs();
    readrow = G_malloc(sizeof(int) * ncb.threads);

    /* open the selection raster map */
    if (parm.selection->answer) {
        G_message(_("Opening selection map <%s>"), parm.selection->answer);
        selection_fd = G_malloc(sizeof(int) * ncb.threads);
        selection = G_malloc(sizeof(char *) * ncb.threads);
        for (t = 0; t < ncb.threads; t++) {
            selection_fd[t] = Rast_open_old(parm.selection->answer, "");
            selection[t] = Rast_allocate_null_buf();
        }
    }
    else {
        selection_fd = NULL;
        selection = NULL;
    }

    if (flag.circle->answer)
        circle_mask();

    values_w = NULL;
    values_w_tmp = NULL;
    if (weights) {
        size = sizeof(DCELL(*)[2]) * ncb.threads;
        values_w = G_malloc(size);
        values_w_tmp = G_malloc(size);

        size = sizeof(DCELL) * 2 * ncb.nsize * ncb.nsize;
        for (t = 0; t < ncb.threads; t++) {
            values_w[t] = G_malloc(size);
            values_w_tmp[t] = G_malloc(size);
        }
    }

    size = sizeof(DCELL *) * ncb.threads;
    values = G_malloc(size);
    values_tmp = G_malloc(size);

    size = sizeof(DCELL) * ncb.nsize * ncb.nsize;
    for (t = 0; t < ncb.threads; t++) {
        values[t] = G_malloc(size);
        values_tmp[t] = G_malloc(size);
    }

    int computed = 0;
    int written = 0;

    t = FIRST_THREAD;
    while (written < nrows) {
        int range;

        if (nrows - computed < brows) {
            range = nrows - computed;
        }
        else {
            range = brows;
        }
#pragma omp parallel private(row, col, n, i, t) if (ncb.threads > 1)
        {
#if defined(_OPENMP)
            t = omp_get_thread_num();
#endif
            int brow_idx = range * t / ncb.threads;
            int start = written + (range * t / ncb.threads);
            int end = written + (range * (t + 1) / ncb.threads);

            /* initialize the cell bufs with 'dist' rows of the old cellfile */
            readrow[t] = start - ncb.dist;
            for (row = start - ncb.dist; row < start + ncb.dist; row++)
                readcell(in_fd[t], readrow[t]++, nrows, ncols, t);

            for (row = start; row < end; row++, brow_idx++) {
                G_percent(computed, nrows, 2);
                readcell(in_fd[t], readrow[t]++, nrows, ncols, t);

                if (selection)
                    Rast_get_null_value_row(selection_fd[t], selection[t], row);

                for (col = 0; col < ncols; col++) {

                    if (selection && selection[t][col]) {
                        /* ncb.buf length is region row length + 2 * ncb.dist
                         * (eq. floor(neighborhood/2)) Thus original data start
                         * is shifted by ncb.dist! */
                        for (i = 0; i < num_outputs; i++)
                            outputs[i].buf[(size_t)brow_idx * ncols + col] =
                                ncb.buf[t][ncb.dist][col + ncb.dist];
                        continue;
                    }

                    if (weights)
                        n = gather_w(values[t], values_w[t], col, t);
                    else
                        n = gather(values[t], col, t);

                    for (i = 0; i < num_outputs; i++) {
                        struct output *out = &outputs[i];
                        DCELL *rp = &out->buf[(size_t)brow_idx * ncols + col];

                        if (n == 0) {
                            Rast_set_d_null_value(rp, 1);
                        }
                        else {
                            if (out->method_fn_w) {
                                memcpy(values_w_tmp[t], values_w[t],
                                       sizeof(DCELL) * n * 2);
                                (*out->method_fn_w)(rp, values_w_tmp[t], n,
                                                    &out->quantile);
                            }
                            else {
                                memcpy(values_tmp[t], values[t],
                                       sizeof(DCELL) * n);
                                (*out->method_fn)(rp, values_tmp[t], n,
                                                  &out->quantile);
                            }
                        }
                    }
                }
#pragma omp atomic update
                computed++;
            }
        }
        for (i = 0; i < num_outputs; i++) {
            struct output *out = &outputs[i];
            DCELL *rowptr = out->buf;

            for (row = written; row < written + range; row++) {
                Rast_put_d_row(out->fd, rowptr);
                rowptr += ncols;
            }
        }
        written = computed;
    }
    G_percent(written, nrows, 2);

    for (t = 0; t < ncb.threads; t++)
        Rast_close(in_fd[t]);

    if (selection)
        for (t = 0; t < ncb.threads; t++)
            Rast_close(selection_fd[t]);

    for (i = 0; i < num_outputs; i++) {
        Rast_close(outputs[i].fd);

        G_free(outputs[i].buf);

        /* put out category info */
        null_cats(outputs[i].title);
        if (outputs[i].cat_names)
            outputs[i].cat_names();

        Rast_write_cats(outputs[i].name, &ncb.cats);

        if (copycolr && outputs[i].copycolr)
            Rast_write_colors(outputs[i].name, G_mapset(), &colr);

        Rast_short_history(outputs[i].name, "raster", &history);
        Rast_command_history(&history);
        Rast_write_history(outputs[i].name, &history);
    }

    exit(EXIT_SUCCESS);
}
