/*
**********************************************************************************************
*	File: maat_group.cpp
*   Description: 
*	Authors: Liu wentan <liuwentan@geedgenetworks.com>
*	Date:    2022-10-31
*   Copyright: (c) 2018-2022 Geedge Networks, Inc. All rights reserved.
***********************************************************************************************
*/

#include <assert.h>
#include <pthread.h>

#include "log/log.h"
#include "maat_group.h"
#include "maat_utils.h"
#include "uthash/uthash.h"
#include "igraph/igraph.h"
#include "maat_kv.h"

#define MODULE_GROUP	 module_name_str("maat.group")

struct group2group_item {
    long long group_id;
    long long super_group_id;
};

struct group2group_schema {
    int group_id_column;
    int super_group_id_column;
    int table_id;//ugly
    struct table_manager *ref_tbl_mgr;
};

struct maat_group {
	igraph_integer_t vertex_id;
	long long group_id;
	int ref_by_super_group_cnt;
	int ref_by_sub_group_cnt;

	size_t top_group_cnt;
	long long *top_group_ids;

	UT_hash_handle hh_group_id;
	UT_hash_handle hh_vertex_id;
};

struct maat_group_topology {
    struct maat_group *hash_group_by_id;	 //key: group_id, value: struct maat_group *.
	struct maat_group *hash_group_by_vertex; //key: vetex_id, value: struct maat_group *. Multimap (Items with multiple keys).
    igraph_t group_graph;
	igraph_integer_t grp_vertex_id_generator;
    struct log_handle *logger;
};

struct group2group_runtime {
    struct maat_group_topology *group_topo;
    struct maat_group_topology *updating_group_topo;
    long long version;
	long long rule_num;
    long long update_err_cnt;
    int updating_flag;

    struct maat_garbage_bin *ref_garbage_bin;
    struct log_handle *logger;
};

void *group2group_schema_new(cJSON *json, struct table_manager *tbl_mgr, 
                             const char *table_name, struct log_handle *logger)
{
	struct group2group_schema *g2g_schema = ALLOC(struct group2group_schema, 1);
	
	cJSON *custom_item = NULL;
    cJSON *item = cJSON_GetObjectItem(json, "table_id");
    if (item != NULL && item->type == cJSON_Number) {
        g2g_schema->table_id = item->valueint;
    } else {
        log_error(logger, MODULE_GROUP, 
                  "[%s:%d] table %s has no table_id column", table_name);
        goto error;
    }

    item = cJSON_GetObjectItem(json, "custom");
    if (item == NULL || item->type != cJSON_Object) {
        log_error(logger, MODULE_GROUP, 
                  "[%s:%d] table %s has no custom column", 
                  __FUNCTION__, __LINE__, table_name);
        goto error;
    }

    custom_item = cJSON_GetObjectItem(item, "group_id");
    if (custom_item != NULL && custom_item->type == cJSON_Number) {
        g2g_schema->group_id_column = custom_item->valueint;
    } else {
        log_error(logger, MODULE_GROUP, 
                  "[%s:%d] table %s has no group_id column", table_name);
        goto error;
    }

    custom_item = cJSON_GetObjectItem(item, "super_group_id");
    if (custom_item != NULL && custom_item->type == cJSON_Number) {
        g2g_schema->super_group_id_column = custom_item->valueint;
    } else {
        log_error(logger, MODULE_GROUP, 
                  "[%s:%d] table %s has no super_group_id column", table_name);
        goto error;
    }

    g2g_schema->ref_tbl_mgr = tbl_mgr;
	return g2g_schema;
error:
	FREE(g2g_schema);
	return NULL;
}

void group2group_schema_free(void *g2g_schema)
{
	FREE(g2g_schema);
}

void group_vertex_free(struct maat_group *group)
{
	FREE(group->top_group_ids);
	FREE(group);
}

struct maat_group_topology *maat_group_topology_new(struct log_handle *logger)
{
    struct maat_group_topology *group_topo = ALLOC(struct maat_group_topology, 1);
    UNUSED int ret = 0;

    group_topo->hash_group_by_id = NULL;
    group_topo->hash_group_by_vertex = NULL;

    ret = igraph_empty(&group_topo->group_graph, 0, IGRAPH_DIRECTED);
    assert(ret == IGRAPH_SUCCESS);

    group_topo->logger = logger;

    return group_topo;
}

void maat_group_topology_free(struct maat_group_topology *group_topo)
{
    struct maat_group *group = NULL, *tmp_group = NULL;

    HASH_CLEAR(hh_vertex_id, group_topo->hash_group_by_vertex);//No need group memory clean up.
	HASH_ITER(hh_group_id, group_topo->hash_group_by_id, group, tmp_group) {
		HASH_DELETE(hh_group_id, group_topo->hash_group_by_id, group);
		group_vertex_free(group);
	}
	assert(group_topo->hash_group_by_id == NULL);	
	
	igraph_destroy(&group_topo->group_graph);
    FREE(group_topo);
}

struct maat_group *maat_group_clone(struct maat_group *group)
{
    struct maat_group *group_copy = ALLOC(struct maat_group, 1);

    group_copy->group_id = group->group_id;
    group_copy->vertex_id = group->vertex_id;
    group_copy->ref_by_sub_group_cnt = group->ref_by_sub_group_cnt;
    group_copy->ref_by_super_group_cnt = group->ref_by_super_group_cnt;
    group_copy->top_group_cnt = group->top_group_cnt;
    if (group_copy->top_group_cnt > 0) {
        group_copy->top_group_ids = ALLOC(long long, group_copy->top_group_cnt);
        memcpy(group_copy->top_group_ids, group->top_group_ids, 
               group_copy->top_group_cnt * sizeof(long long));
    }

    return group_copy;
}

struct maat_group_topology *maat_group_topology_clone(struct maat_group_topology *group_topo)
{
    if (NULL == group_topo) {
        return NULL;
    }

    struct maat_group_topology *group_topo_copy = ALLOC(struct maat_group_topology, 1);

    struct maat_group *group = NULL, *tmp_group = NULL;
    HASH_ITER(hh_group_id, group_topo->hash_group_by_id, group, tmp_group) {
        struct maat_group *group_copy = maat_group_clone(group);

        HASH_ADD(hh_group_id, group_topo_copy->hash_group_by_id, group_id, 
                 sizeof(group_copy->group_id), group_copy);
        HASH_ADD(hh_vertex_id, group_topo_copy->hash_group_by_vertex, vertex_id,
                sizeof(group_copy->vertex_id), group_copy);
    }

    igraph_copy(&(group_topo_copy->group_graph), &(group_topo->group_graph));
    group_topo_copy->grp_vertex_id_generator = group_topo->grp_vertex_id_generator;
    group_topo_copy->logger = group_topo->logger;

    return group_topo_copy;
}

void *group2group_runtime_new(void *g2g_schema, size_t max_thread_num,
                              struct maat_garbage_bin *garbage_bin, 
                              struct log_handle *logger)
{
    if (NULL == g2g_schema) {
        return NULL;
    }

	struct group2group_runtime *g2g_rt = ALLOC(struct group2group_runtime, 1);

	g2g_rt->group_topo = maat_group_topology_new(logger);
    g2g_rt->ref_garbage_bin = garbage_bin;
    g2g_rt->logger = logger;

	return g2g_rt;
}

void group2group_runtime_free(void *g2g_runtime)
{
    if (NULL == g2g_runtime) {
        return;
    }

    struct group2group_runtime *g2g_rt = (struct group2group_runtime *)g2g_runtime;

    if (g2g_rt->group_topo != NULL) {
        maat_group_topology_free(g2g_rt->group_topo);
        g2g_rt->group_topo = NULL;
    }
    
    if (g2g_rt->updating_group_topo != NULL) {
        maat_group_topology_free(g2g_rt->updating_group_topo);
        g2g_rt->updating_group_topo = NULL;
    }

    FREE(g2g_rt);
}

struct group2group_item *
group2group_item_new(const char *line, struct group2group_schema *g2g_schema,
                     const char *table_name, struct log_handle *logger)
{
    size_t column_offset = 0;
    size_t column_len = 0;
    struct group2group_item *g2g_item = ALLOC(struct group2group_item, 1);

    int ret = get_column_pos(line, g2g_schema->group_id_column, &column_offset, &column_len);
    if (ret < 0) {
        log_error(logger, MODULE_GROUP,
                  "[%s:%d] group2group table:%s line:%s has no group_id",
                  __FUNCTION__, __LINE__, table_name, line);
        goto error;
    }
    g2g_item->group_id = atoll(line + column_offset);

    ret = get_column_pos(line, g2g_schema->super_group_id_column, 
                         &column_offset, &column_len);
    if (ret < 0) {
        log_error(logger, MODULE_GROUP,
                  "[%s:%d] group2group table:%s line:%s has no super_group_id",
                  __FUNCTION__, __LINE__, table_name, line);
        goto error;
    }
    g2g_item->super_group_id = atoll(line + column_offset);

    return g2g_item;
error:
    FREE(g2g_item);
    return NULL;
}

void group2group_item_free(struct group2group_item *g2g_item)
{
    FREE(g2g_item);
}

size_t print_igraph_vector(igraph_vector_t *v, char *buff, size_t sz) {
  long int i;
  int printed = 0;

  for (i = 0; i < igraph_vector_size(v); i++) {
    printed += snprintf(buff + printed, sz - printed, " %li", (long int) VECTOR(*v)[i]);
  }

  return printed;
}

struct maat_group *group_topology_add_group(struct maat_group_topology *group_topo, 
                                            long long group_id)
{
    assert(group_topo != NULL);

	struct maat_group *group = ALLOC(struct maat_group, 1);
	group->group_id = group_id;
	group->vertex_id = group_topo->grp_vertex_id_generator++;

	assert(igraph_vcount(&group_topo->group_graph)==group->vertex_id);
	igraph_add_vertices(&group_topo->group_graph, 1, NULL);	//Add 1 vertice.
	
	HASH_ADD(hh_group_id, group_topo->hash_group_by_id, group_id, sizeof(group->group_id), group);
	HASH_ADD(hh_vertex_id, group_topo->hash_group_by_vertex, vertex_id, sizeof(group->vertex_id), group);
    
	return group;
}

void group_topology_remove_group(struct maat_group_topology *group_topo,
                                 struct maat_group *group)
{
    if (NULL == group_topo || NULL == group) {
        return;
    }

    igraph_vector_t v; 
	char buff[4096] = {0};

    assert(group->ref_by_super_group_cnt == 0);

	igraph_vector_init(&v, 8);
	igraph_neighbors(&group_topo->group_graph, &v, group->vertex_id, IGRAPH_ALL);
	if (igraph_vector_size(&v) > 0) {
		print_igraph_vector(&v, buff, sizeof(buff));
		log_error(group_topo->logger, MODULE_GROUP, 
                 "[%s:%d] Del group %d exception, still reached by %s.",
				  __FUNCTION__, __LINE__, group->vertex_id, buff);
		assert(0);
	}
	igraph_vector_destroy(&v);
	assert(group->top_group_ids==NULL);
	//We should not call igraph_delete_vertices, because this is function changes the ids of the vertices.
	//igraph_delete_vertices(&hier->group_graph, igraph_vss_1(group->vertex_id));

	HASH_DELETE(hh_group_id, group_topo->hash_group_by_id, group);
	HASH_DELETE(hh_vertex_id, group_topo->hash_group_by_vertex, group);
	group_vertex_free(group);
}

struct maat_group *group_topology_find_group(struct maat_group_topology *group_topo,
                                             long long group_id)
{
    if (NULL == group_topo || group_id < 0) {
        return NULL;
    }

    struct maat_group *group = NULL;
    HASH_FIND(hh_group_id, group_topo->hash_group_by_id, &group_id, sizeof(group_id), group);

    return group;
}

int group_topology_add_group_to_group(struct maat_group_topology *group_topo, 
                                      long long group_id, long long super_group_id)
{
    if (NULL == group_topo) {
        return -1;
    }
	
    struct maat_group *group = group_topology_find_group(group_topo, group_id);
	if (NULL == group) {
		group = group_topology_add_group(group_topo, group_id);
	}
	
    struct maat_group *super_group = group_topology_find_group(group_topo, super_group_id);
	if (NULL == super_group) {
		super_group = group_topology_add_group(group_topo, super_group_id);
	}

    igraph_integer_t edge_id;
	int ret = igraph_get_eid(&group_topo->group_graph, &edge_id, group->vertex_id, 
                             super_group->vertex_id, IGRAPH_DIRECTED, /*error*/ 0);
	
    //No duplicated edges between two groups.
    if (edge_id > 0) {
		log_error(group_topo->logger, MODULE_GROUP,
                  "[%s:%d] Add group %d to group %d failed, relation already exisited.",
				  __FUNCTION__, __LINE__, group->group_id, super_group->group_id);
		ret = -1;
	} else {
		igraph_add_edge(&group_topo->group_graph, group->vertex_id, 
                        super_group->vertex_id);
		group->ref_by_super_group_cnt++;
		super_group->ref_by_sub_group_cnt++;
		ret = 0;
	}

	return ret;
}

int group_topology_remove_group_from_group(struct maat_group_topology *group_topo, 
                                           long long group_id, long long super_group_id)
{
    if (NULL == group_topo) {
        return -1;
    }

	//No hash write operation, LOCK protection is unnecessary.
	struct maat_group *group = group_topology_find_group(group_topo, group_id);
	if (NULL == group) {
		log_error(group_topo->logger, MODULE_GROUP,
				  "[%s:%d] Del group %d from group %d failed, group %d not exisited.",
				  __FUNCTION__, __LINE__, group_id, super_group_id, group_id);
		return -1;	
	}

    struct maat_group *super_group = group_topology_find_group(group_topo, super_group_id);
	if (NULL == super_group) {
		log_error(group_topo->logger, MODULE_GROUP,
				  "[%s:%d] Del group %d from group %d failed, superior group %d not exisited.",
				  __FUNCTION__, __LINE__, group_id, super_group_id, super_group_id);
		return -1;	
	}

	igraph_es_t es;
	igraph_integer_t edge_num_before = 0, edge_num_after = 0;

	edge_num_before = igraph_ecount(&group_topo->group_graph);
	// The edges between the given pairs of vertices will be included in the edge selection.
	//The vertex pairs must be given as the arguments of the function call, the third argument 
	//is the first vertex of the first edge, the fourth argument is the second vertex of the 
	//first edge, the fifth is the first vertex of the second edge and so on. The last element
	//of the argument list must be -1 to denote the end of the argument list.
	//https://igraph.org/c/doc/igraph-Iterators.html#igraph_es_pairs_small
	int ret = igraph_es_pairs_small(&es, IGRAPH_DIRECTED, group->vertex_id, 
                                    super_group->vertex_id, -1);
	assert(ret==IGRAPH_SUCCESS);
	// ignore no such edge to abort().
	igraph_set_error_handler(igraph_error_handler_ignore);
	ret = igraph_delete_edges(&group_topo->group_graph, es);
	edge_num_after = igraph_ecount(&group_topo->group_graph);
	igraph_es_destroy(&es);
	
	if (ret != IGRAPH_SUCCESS || edge_num_before - edge_num_after != 1) {
		assert(0);
		return -1;
	}

	group->ref_by_super_group_cnt--;
	super_group->ref_by_sub_group_cnt--;

	return 0;
}

static size_t effective_vertices_count(igraph_vector_t *vids)
{
    size_t i = 0;
	int tmp_vid = 0;

	for (i = 0; i < (size_t)igraph_vector_size(vids); i++) {
		tmp_vid = (int) VECTOR(*vids)[i];
		if (tmp_vid < 0) {
			break;
		}
	}

	return i;
}

int group_topology_build_top_groups(struct maat_group_topology *group_topo)
{
    if (NULL == group_topo) {
        return -1;
    }

	struct maat_group *group = NULL, *tmp = NULL;
	struct maat_group *super_group = NULL;
	int tmp_vid = 0;
	size_t top_group_cnt = 0;
	long long *temp_group_ids = NULL;

	igraph_bool_t is_dag;
	igraph_is_dag(&(group_topo->group_graph), &is_dag);
	if (!is_dag) {
		log_error(group_topo->logger, MODULE_GROUP, "[%s:%d] Sub group cycle detected!",
                  __FUNCTION__, __LINE__);
		return -1;
	}

	igraph_integer_t group_graph_vcount = igraph_vcount(&group_topo->group_graph);
    igraph_vector_t dfs_vids;
	igraph_vector_init(&dfs_vids, group_graph_vcount);
	
	HASH_ITER (hh_group_id, group_topo->hash_group_by_id, group, tmp) {
		top_group_cnt = 0;
		temp_group_ids = NULL;
        
		//Orphan, Not reference by any one, free it.
		if (0 == group->ref_by_super_group_cnt
			&& 0 == group->ref_by_sub_group_cnt) {
		
			FREE(group->top_group_ids);
			group_topology_remove_group(group_topo, group);
			continue;
		}

		//A group is referenced by superior groups.
        if (group->ref_by_super_group_cnt > 0) {
            igraph_vector_t *vids = &dfs_vids;
            igraph_dfs(&group_topo->group_graph, group->vertex_id, IGRAPH_OUT,
                       0, vids, NULL, NULL, NULL, NULL, NULL, NULL);

            temp_group_ids = ALLOC(long long, effective_vertices_count(vids));

            for (size_t i = 0; i < (size_t)igraph_vector_size(vids); i++) {
                tmp_vid = (int)VECTOR(*vids)[i];
                if (tmp_vid < 0) {
                    break;
                }

                HASH_FIND(hh_vertex_id, group_topo->hash_group_by_vertex, &tmp_vid,
                          sizeof(tmp_vid), super_group);

                temp_group_ids[top_group_cnt] = super_group->group_id;
                top_group_cnt++;
            }
        }

        FREE(group->top_group_ids);
		group->top_group_cnt = top_group_cnt;
        if (top_group_cnt > 0) {
            group->top_group_ids = ALLOC(long long, group->top_group_cnt);
		    memcpy(group->top_group_ids, temp_group_ids, sizeof(long long)*group->top_group_cnt);
        }
		
        if (temp_group_ids != NULL) {
            FREE(temp_group_ids);
        }
	}
	igraph_vector_destroy(&dfs_vids);

	return 0;
}

int group2group_runtime_update(void *g2g_runtime, void *g2g_schema, 
                               const char *table_name, const char *line, 
                               int valid_column)
{
    if (NULL == g2g_runtime || NULL == g2g_schema || 
        NULL == line) {
        return -1;
    }

	int ret = -1;
    struct group2group_schema *schema = (struct group2group_schema *)g2g_schema;
	struct group2group_runtime *g2g_rt = (struct group2group_runtime *)g2g_runtime;
    int is_valid = get_column_value(line, valid_column);
    if (is_valid < 0) {
        g2g_rt->update_err_cnt++;
        return -1;
    }

    struct group2group_item *g2g_item = group2group_item_new(line, schema, table_name, 
                                                             g2g_rt->logger);
    if (NULL == g2g_item) {
        g2g_rt->update_err_cnt++;
        return -1;
    }
    
    if (0 == g2g_rt->updating_flag) {
        assert(g2g_rt->updating_group_topo == NULL);
        g2g_rt->updating_group_topo = maat_group_topology_clone(g2g_rt->group_topo);
        g2g_rt->updating_flag = 1;
    }

    if (0 == is_valid) {
        //delete
        ret = group_topology_remove_group_from_group(g2g_rt->updating_group_topo, g2g_item->group_id, 
                                                     g2g_item->super_group_id);
        if (0 == ret) {
            g2g_rt->rule_num--;
        } else {
            g2g_rt->update_err_cnt++;
        }
    } else {
        //add
        ret = group_topology_add_group_to_group(g2g_rt->updating_group_topo, g2g_item->group_id, 
                                                g2g_item->super_group_id);
        if (0 == ret) {
            g2g_rt->rule_num++;
        } else {
            g2g_rt->update_err_cnt++;
        }
    }
    group2group_item_free(g2g_item);

    return ret;
}

void garbage_maat_group_topology_free(void *data, void *arg)
{
    struct maat_group_topology *group_topo = (struct maat_group_topology *)data;
    maat_group_topology_free(group_topo);
}

int group2group_runtime_commit(void *g2g_runtime, const char *table_name, long long maat_rt_version)
{
    if (NULL == g2g_runtime) {
		return -1;
	}

    struct group2group_runtime *g2g_rt = (struct group2group_runtime *)g2g_runtime;
    if (0 == g2g_rt->updating_flag) {
        return 0;
    }

    int ret = group_topology_build_top_groups(g2g_rt->updating_group_topo);
    if (ret < 0) {
        log_error(g2g_rt->logger, MODULE_GROUP, 
                  "[%s:%d] table[%s] group2group runtime commit failed", 
                  __FUNCTION__, __LINE__, table_name);
        return -1;
    }

    struct maat_group_topology *old_group_topo = g2g_rt->group_topo;
    g2g_rt->group_topo = g2g_rt->updating_group_topo;
    g2g_rt->updating_group_topo = NULL;
    g2g_rt->updating_flag = 0;

    maat_garbage_bagging(g2g_rt->ref_garbage_bin, old_group_topo, NULL, 
                         garbage_maat_group_topology_free);
    g2g_rt->version = maat_rt_version;

    log_info(g2g_rt->logger, MODULE_GROUP,
             "table[%s] commit %zu g2g rules and rebuild top_groups completed, version:%lld",
             table_name, g2g_rt->rule_num, g2g_rt->version);

    return 0;
}

long long group2group_runtime_rule_count(void *g2g_runtime)
{
    if (NULL == g2g_runtime) {
        return 0;
    }
    
    struct group2group_runtime *g2g_rt = (struct group2group_runtime *)g2g_runtime;
    return g2g_rt->rule_num;
}

long long group2group_runtime_update_err_count(void *g2g_runtime)
{
    if (NULL == g2g_runtime) {
        return 0;
    }
    
    struct group2group_runtime *g2g_rt = (struct group2group_runtime *)g2g_runtime;
    return g2g_rt->update_err_cnt;
}

int group2group_runtime_get_top_groups(void *g2g_runtime, long long *group_ids, 
                                       size_t n_group_ids, long long *top_group_ids)
{
    if (NULL == g2g_runtime || NULL == group_ids || 0 == n_group_ids) {
        return -1;
    }
    
    size_t top_group_index = 0;
    struct group2group_runtime *g2g_rt = (struct group2group_runtime *)g2g_runtime;

    for (size_t i = 0; i < n_group_ids; i++) {
        struct maat_group *group = group_topology_find_group(g2g_rt->group_topo, group_ids[i]);
        if (!group) {
            continue;
        }

        for (size_t j = 0; j < group->top_group_cnt; j++) {
            top_group_ids[top_group_index++] = group->top_group_ids[j];
        }
    }

    return top_group_index;
}