#include <stddef.h>
#include "menu_driver.h"
#include "menu_cbs.h"
#include "../retroarch.h"
#include "../configuration.h"
#include "../playlist.h"
#include "../libretro-db/libretrodb.h"
#include <compat/strcasestr.h>
#include <compat/strl.h>

// Stretchy buffers, invented (?) by Sean Barrett
#define ex_buf__hdr(b) (((struct ex_buf_hdr *)(b))-1)

#define ex_buf_len(b) ((b) ? ex_buf__hdr(b)->len : 0)
#define ex_buf_cap(b) ((b) ? ex_buf__hdr(b)->cap : 0)
#define ex_buf_end(b) ((b) + ex_buf_len(b))
#define ex_buf_sizeof(b) ((b) ? ex_buf_len(b)*sizeof(*b) : 0)

#define ex_buf_free(b) ((b) ? (free(ex_buf__hdr(b)), (b) = NULL) : 0)
#define ex_buf_fit(b, n) ((size_t)(n) <= ex_buf_cap(b) ? 0 : (*(void**)(&(b)) = ex_buf__grow((b), (n), sizeof(*(b)))))
#define ex_buf_push(b, ...) (ex_buf_fit((b), 1 + ex_buf_len(b)), (b)[ex_buf__hdr(b)->len++] = __VA_ARGS__)
#define ex_buf_pop(b) (b)[--ex_buf__hdr(b)->len]
#define ex_buf_resize(b, sz) (ex_buf_fit((b), (sz)), ((b) ? ex_buf__hdr(b)->len = (sz) : 0))
#define ex_buf_clear(b) ((b) ? ex_buf__hdr(b)->len = 0 : 0)

struct ex_buf_hdr { size_t len, cap; };
static void *ex_buf__grow(const void *buf, size_t new_len, size_t elem_size)
{
	size_t new_cap = MAX(2 * ex_buf_cap(buf), MAX(new_len, 16));
	size_t new_size = sizeof(struct ex_buf_hdr) + new_cap*elem_size;
	struct ex_buf_hdr *new_hdr;
	if (buf)
		new_hdr = (struct ex_buf_hdr *)realloc(ex_buf__hdr(buf), new_size);
	else
		(new_hdr = (struct ex_buf_hdr *)malloc(new_size))->len = 0;
	new_hdr->cap = new_cap;
	return new_hdr + 1;
}

// Arena allocator
typedef struct ex_arena
{
	char *ptr, *end, **blocks;
} ex_arena;

#define EX_ARENA_ALIGNMENT 8
#define EX_ARENA_BLOCK_SIZE (64 * 1024)
#define EX_ARENA_ALIGN_UP(n, a) (((n) + (a) - 1) & ~((a) - 1))

static void ex_arena_grow(ex_arena *arena, size_t min_size)
{
	size_t size = EX_ARENA_ALIGN_UP(MAX(min_size, EX_ARENA_BLOCK_SIZE), EX_ARENA_ALIGNMENT);
	arena->ptr = (char *)malloc(size);
	arena->end = arena->ptr + size;
	ex_buf_push(arena->blocks, arena->ptr);
}

static void *ex_arena_alloc(ex_arena *arena, size_t size)
{
	if (size > (size_t)(arena->end - arena->ptr))
		ex_arena_grow(arena, size);
	void *ptr = arena->ptr;
	arena->ptr = (char *)EX_ARENA_ALIGN_UP((uintptr_t)(arena->ptr + size), EX_ARENA_ALIGNMENT);
	return ptr;
}

static void ex_arena_free(ex_arena *arena)
{
	for (char **it = arena->blocks; it != ex_buf_end(arena->blocks); it++)
		free(*it);
	ex_buf_free(arena->blocks);
	arena->ptr = arena->end = NULL;
	arena->blocks = NULL;
}

//Hash function
static uint32_t ex_hash32(const char* str)
{
	uint32_t hash = (uint32_t)0x811c9dc5;
	for (unsigned char c; (c = *(str++)) != '\0';)
		hash = ((hash * (uint32_t)0x01000193) ^ (uint32_t)c);
	return (hash ? hash : 1);
}

static uint32_t ex_hash32_nocase_filtered(const unsigned char* str, size_t len, unsigned char f_first, unsigned char f_last)
{
	uint32_t hash = (uint32_t)0x811c9dc5;
	for (const unsigned char *end = str + len; str != end;)
	{
		unsigned char c = *(str++);
		if (c >= f_first && c <= f_last)
			hash = ((hash * (uint32_t)0x01000193) ^ (uint32_t)((c >= 'A' && c <= 'Z') ? (c | 0x20) : c));
	}
	return (hash ? hash : 1);
}

//Hashmap
typedef struct ex_hashmap32
{
	uint32_t len, cap, *keys;
	uintptr_t* vals;
} ex_hashmap32;

static void ex_hashmap32__grow(ex_hashmap32* map, uint32_t new_cap)
{
	uint32_t oldCap = map->cap, *oldKeys = map->keys;
	uintptr_t *oldVals = map->vals;
	map->cap = (new_cap < 16 ? 16 : new_cap);
	map->keys = (uint32_t *)calloc(map->cap, sizeof(uint32_t));
	map->vals = (uintptr_t *)malloc(map->cap * sizeof(uintptr_t));
	for (size_t i = 0; i < oldCap; i++)
	{
		if (!oldKeys[i]) continue;
		for (uint32_t key = oldKeys[i], j = key;; j++)
		{
			if (!map->keys[j &= map->cap - 1]) { map->keys[j] = key; map->vals[j] = oldVals[i]; break; }
		}
	}
	free(oldKeys);
	free(oldVals);
}

static void ex_hashmap32_free(ex_hashmap32* map) { free(map->keys); free(map->vals); }

static uintptr_t ex_hashmap32_getnum(ex_hashmap32* map, uint32_t key)
{
	if (map->len == 0 || !key) return 0;
	for (uint32_t i = key;; i++)
	{
		if (map->keys[i &= map->cap - 1] == key) return map->vals[i];
		if (!map->keys[i]) return 0;
	}
}

static void ex_hashmap32_setnum(ex_hashmap32* map, uint32_t key, uintptr_t val)
{
	if (!key) return;
	if (2 * map->len >= map->cap) ex_hashmap32__grow(map, 2 * map->cap);
	for (uint32_t i = key;; i++)
	{
		if (!map->keys[i &= map->cap - 1]) { map->len++; map->keys[i] = key; map->vals[i] = val; return; }
		if (map->keys[i] == key) { map->vals[i] = val; return; }
	}
}

static INLINE void*     ex_hashmap32_getptr   (ex_hashmap32* map, uint32_t key)                   { return (void*)ex_hashmap32_getnum(map, key); }
static INLINE void      ex_hashmap32_setptr   (ex_hashmap32* map, uint32_t key, void* ptr)        { ex_hashmap32_setnum(map, key, (uintptr_t)ptr); }
static INLINE void*     ex_hashmap32_strgetptr(ex_hashmap32* map, const char* str)                { return (void*)ex_hashmap32_getnum(map, ex_hash32(str)); }
static INLINE void      ex_hashmap32_strsetptr(ex_hashmap32* map, const char* str, void* ptr)     { ex_hashmap32_setnum(map, ex_hash32(str), (uintptr_t)ptr); }
static INLINE uintptr_t ex_hashmap32_strgetnum(ex_hashmap32* map, const char* str)                { return ex_hashmap32_getnum(map, ex_hash32(str)); }
static INLINE void      ex_hashmap32_strsetnum(ex_hashmap32* map, const char* str, uintptr_t num) { ex_hashmap32_setnum(map, ex_hash32(str), num); }

// Explore
enum
{
	EXPLORE_BY_DEVELOPER,
	EXPLORE_BY_PUBLISHER,
	EXPLORE_BY_RELEASEYEAR,
	EXPLORE_BY_PLAYERCOUNT,
	EXPLORE_BY_GENRE,
	EXPLORE_BY_ORIGIN,
	EXPLORE_BY_REGION,
	EXPLORE_BY_FRANCHISE,
	EXPLORE_BY_TAGS,
	EXPLORE_BY_SYSTEM,
	EXPLORE_CAT_COUNT,

	EXPLORE_TYPE_ADDITIONALFILTER = FILE_TYPE_RDB, //database icon
	EXPLORE_TYPE_FILTERNULL = MENU_SETTINGS_LAST,
	EXPLORE_TYPE_SEARCH,
	EXPLORE_TYPE_SHOWALL,
	EXPLORE_TYPE_FIRSTCATEGORY,
	EXPLORE_TYPE_FIRSTITEM = EXPLORE_TYPE_FIRSTCATEGORY + EXPLORE_CAT_COUNT,
};

static const struct { const char *name, *rdbkey; bool use_split, is_company, is_numeric; }
	explore_by_info[EXPLORE_CAT_COUNT] = 
{
	{ "Developer",    "developer",   true,  true,  false },
	{ "Publisher",    "publisher",   true,  true,  false },
	{ "Release Year", "releaseyear", false, false, true  },
	{ "Player Count", "users",       false, false, true  },
	{ "Genre",        "genre",       true,  false, false },
	{ "Origin",       "origin",      false, false, false },
	{ "Region",       "region",      false, false, false },
	{ "Franchise",    "franchise",   false, false, false },
	{ "Tags",         "tags",        true,  false, false },
	{ "System",       "system",      false, false, false },
};

typedef struct
{
	uint32_t idx;
	char str[1];
} explore_string_t;

typedef struct
{
	const struct playlist_entry* playlist_entry;
	explore_string_t *by[EXPLORE_CAT_COUNT];
	explore_string_t **split;
	char* original_title;
} explore_entry_t;

typedef struct 
{
	ex_arena arena;
	explore_string_t **by[EXPLORE_CAT_COUNT];
	bool has_unknown[EXPLORE_CAT_COUNT];

	explore_entry_t* entries;
	playlist_t **playlists;
	const char* label_explore_item_str;
	char title[1024];
	char find_string[1024];
	unsigned top_depth;
} explore_state_t;

static explore_state_t* explore_state;

static int explore_qsort_func_strings(const void *a_, const void *b_)
{
	const explore_string_t **a = (const explore_string_t**)a_;
	const explore_string_t **b = (const explore_string_t**)b_;
	if ((*a)->str[0] != (*b)->str[0])
		return (unsigned char)(*a)->str[0] - (unsigned char)(*b)->str[0];
	return strcasecmp((*a)->str, (*b)->str);
}

static int explore_qsort_func_entries(const void *a_, const void *b_)
{
	const explore_entry_t *a = (const explore_entry_t*)a_;
	const explore_entry_t *b = (const explore_entry_t*)b_;
	if (a->playlist_entry->label[0] != b->playlist_entry->label[0])
		return (unsigned char)a->playlist_entry->label[0] - (unsigned char)b->playlist_entry->label[0];
	return strcasecmp(a->playlist_entry->label, b->playlist_entry->label);
}

static int explore_qsort_func_menulist(const void *a_, const void *b_)
{
	const struct item_file *a = (const struct item_file*)a_;
	const struct item_file *b = (const struct item_file*)b_;
	if (a->path[0] != b->path[0])
		return (unsigned char)a->path[0] - (unsigned char)b->path[0];
	return strcasecmp(a->path, b->path);
}

static int explore_check_company_suffix(const char* p, bool search_reverse)
{
	if (search_reverse)
	{
		p -= (p[-1] == '.' ? 4 : 3);
		if (p[-1] != ' ') return 0;
	}
	if (tolower(p[0]) == 'i' && tolower(p[1]) == 'n' && tolower(p[2]) == 'c') return (p[3] == '.' ? 4 : 3); //, Inc
	if (tolower(p[0]) == 'l' && tolower(p[1] )== 't' && tolower(p[2]) == 'd') return (p[3] == '.' ? 4 : 3); //, Ltd
	if (tolower(p[0]) == 't' && tolower(p[1] )== 'h' && tolower(p[2]) == 'e') return (p[3] == '.' ? 4 : 3); //, The
	return 0;
}

static void explore_add_unique_string(ex_hashmap32 *maps, explore_entry_t *e, unsigned cat, const char *str, explore_string_t ***split_buf)
{
	if (!str || !*str)
	{
		explore_state->has_unknown[cat] = true;
		return;
	}

	if (!explore_by_info[cat].use_split) split_buf = NULL;
	bool is_company = explore_by_info[cat].is_company;

	for (const char *p = str + 1, *p_next;; p++)
	{
		if (*p != '/' && *p != ',' && *p != '|' && *p != '\0')
			continue;

		if (!split_buf && *p != '\0') continue;

		p_next = p;
		while (*str == ' ') str++;
		while (p[-1] == ' ') p--;

		if (p == str)
		{
			if (*p == '\0') return;
			continue;
		}

		if (is_company && p - str > 5)
		{
			p -= explore_check_company_suffix(p, true);
			while (p[-1] == ' ') p--;
		}

		size_t len = p - str;
		uint32_t hash = ex_hash32_nocase_filtered((unsigned char*)str, len, '0', 255);
		explore_string_t* entry = (explore_string_t*)ex_hashmap32_getptr(&maps[cat], hash);
		if (!entry)
		{
			entry = (explore_string_t*)ex_arena_alloc(&explore_state->arena, sizeof(explore_string_t) + len);
			memcpy(entry->str, str, len);
			entry->str[len] = '\0';
			ex_buf_push(explore_state->by[cat], entry);
			ex_hashmap32_setptr(&maps[cat], hash, entry);
		}

		if (!e->by[cat]) e->by[cat] = entry;
		else ex_buf_push(*split_buf, entry);

		if (*p_next == '\0') return;
		if (is_company && *p_next == ',')
		{
			p = p_next + 1;
			while (*p == ' ') p++;
			p += explore_check_company_suffix(p, false);
			while (*p == ' ') p++;
			if (*p == '\0') return;
			if (*p == '/' || *p == ',' || *p == '|') p_next = p;
		}
		p = p_next;
		str = p + 1;
	}
}

static void explore_free()
{
	for (int i = 0; i != EXPLORE_CAT_COUNT; i++)
		ex_buf_free(explore_state->by[i]);

	ex_buf_free(explore_state->entries);

	for (size_t i = 0; i != ex_buf_len(explore_state->playlists); i++)
		playlist_free(explore_state->playlists[i]);
	ex_buf_free(explore_state->playlists);

	ex_arena_free(&explore_state->arena);
	free(explore_state);
	explore_state = NULL;
}

static void explore_build_list()
{
	char tmp[PATH_MAX_LENGTH];

	if (explore_state)
		explore_free();

	explore_state = calloc(1, sizeof(explore_state_t));
	explore_state->label_explore_item_str = msg_hash_to_str(MENU_ENUM_LABEL_EXPLORE_ITEM);

	settings_t *settings           = config_get_ptr();
	const char *directory_playlist = settings->paths.directory_playlist;
	const char *directory_database = settings->paths.path_content_database;

	ex_hashmap32 rdb_indices = {0};
	struct explore_rdb { libretrodb_t *handle; ex_hashmap32 playlist_entries; } *rdbs = NULL;

	// Index all playlists
	for (libretro_vfs_implementation_dir *dir = retro_vfs_opendir_impl(directory_playlist, false); dir;)
	{
		if (!retro_vfs_readdir_impl(dir)) { retro_vfs_closedir_impl(dir); break; }

		playlist_config_t playlist_config = {0};
		const char* fname = retro_vfs_dirent_get_name_impl(dir), *fext = (fname ? strrchr(fname, '.') : NULL);
		if (!fext || strcasecmp(fext, ".lpl"))
			continue;

		fill_pathname_join(playlist_config.path, directory_playlist, fname, sizeof(playlist_config.path));
		playlist_config.capacity = COLLECTION_SIZE;
		playlist_t *playlist = playlist_init(&playlist_config);

		size_t used_entries = 0;
		for (size_t j = 0; j < playlist_size(playlist); j++)
		{
			const struct playlist_entry *entry  = NULL;
			playlist_get_index(playlist, j, &entry);

			// Maybe remove this to also include playlist entries with no crc/db/label (build label from file name)
			if (!entry->crc32 || !*entry->crc32 || !entry->db_name || !*entry->db_name || !entry->label || !*entry->label) continue;

			uintptr_t rdb_num = ex_hashmap32_strgetnum(&rdb_indices, entry->db_name);
			if (!rdb_num)
			{
				struct explore_rdb rdb = { libretrodb_new() };
				fill_pathname_join_noext(tmp, directory_database, entry->db_name, sizeof(tmp));
				strlcat(tmp, ".rdb", sizeof(tmp));
				if (libretrodb_open(tmp, rdb.handle) != 0)
				{
					// invalid rdb file
					libretrodb_free(rdb.handle);
					ex_hashmap32_strsetnum(&rdb_indices, entry->db_name, (uintptr_t)-1);
					continue;
				}

				ex_buf_push(rdbs, rdb);
				rdb_num = (uintptr_t)ex_buf_len(rdbs);
				ex_hashmap32_strsetnum(&rdb_indices, entry->db_name, rdb_num);
			}

			if (rdb_num == (uintptr_t)-1)
				continue;

			struct explore_rdb* rdb = &rdbs[rdb_num - 1];
			uint32_t entry_crc32 = (uint32_t)strtoul(entry->crc32, NULL, 16);
			ex_hashmap32_setptr(&rdb->playlist_entries, entry_crc32, (void*)entry);
			used_entries++;
		}

		if (used_entries)
			ex_buf_push(explore_state->playlists, playlist);
		else
			playlist_free(playlist);
	}

	ex_hashmap32 map_cores = {0};
	core_info_list_t *core_list = NULL;
	if (core_info_get_list(&core_list) && core_list)
		for (size_t i = 0; i != core_list->count; i++)
			ex_hashmap32_strsetptr(&map_cores, core_list->list[i].display_name, &core_list->list[i]);

	// Loop through all RDBs referenced in the playlists and load meta data strings
	explore_string_t **split_buf = NULL;
	ex_hashmap32 cat_maps[EXPLORE_CAT_COUNT] = {{0}};
	for (size_t i = 0; i != ex_buf_len(rdbs); i++)
	{
		struct explore_rdb* rdb = &rdbs[i];

		struct rmsgpack_dom_value item;
		libretrodb_cursor_t *cur = libretrodb_cursor_new();
		bool more = (libretrodb_cursor_open(rdb->handle, cur, NULL) == 0
				&& libretrodb_cursor_read_item(cur, &item) == 0);

		for (; more; more = (rmsgpack_dom_value_free(&item), libretrodb_cursor_read_item(cur, &item) == 0))
		{
			uint32_t crc32;
			char numeric_buf[EXPLORE_CAT_COUNT][16];
			char* fields[EXPLORE_CAT_COUNT] = {NULL};
			char* original_title            = NULL;
			bool found_crc32                = false;
         core_info_t* core_info          = NULL;

			if (item.type != RDT_MAP)
				continue;

			for (unsigned i = 0; i < item.val.map.len; i++)
			{
				struct rmsgpack_dom_value *key = &item.val.map.items[i].key;
				struct rmsgpack_dom_value *val = &item.val.map.items[i].value;
				if (!key || !val || key->type != RDT_STRING)
					continue;

				const char* key_str = key->val.string.buff;
				if (string_is_equal(key_str, "crc"))
				{
					crc32 = swap_if_little32(*(uint32_t*)val->val.binary.buff);
					found_crc32 = true;
					continue;
				}
				if (string_is_equal(key_str, "original_title"))
				{
					original_title = val->val.string.buff;
					continue;
				}
				for (unsigned cat = 0; cat != EXPLORE_CAT_COUNT; cat++)
				{
					if (!string_is_equal(key_str, explore_by_info[cat].rdbkey)) continue;
					if (explore_by_info[cat].is_numeric)
					{
						if (!val->val.int_) break;
						snprintf(numeric_buf[cat], sizeof(numeric_buf[cat]), "%d", (int)val->val.int_);
						fields[cat] = numeric_buf[cat];
						break;
					}
					if (val->type != RDT_STRING) break;
					fields[cat] = val->val.string.buff;
					break;
				}
			}

			if (!found_crc32)
				continue;

			const struct playlist_entry *entry = (const struct playlist_entry *)ex_hashmap32_getptr(&rdb->playlist_entries, crc32);
			if (!entry)
				continue;

			explore_entry_t e = {entry};
			for (unsigned cat = 0; cat != EXPLORE_CAT_COUNT; cat++)
				explore_add_unique_string(cat_maps, &e, cat, fields[cat], &split_buf);

         if (!string_is_empty(entry->core_name))
            core_info = (core_info_t*)ex_hashmap32_strgetptr(&map_cores, entry->core_name);
			explore_add_unique_string(cat_maps, &e, EXPLORE_BY_SYSTEM, (core_info ? core_info->systemname : NULL), NULL);

			if (original_title && *original_title)
			{
				size_t len = strlen(original_title) + 1;
				e.original_title = (char*)ex_arena_alloc(&explore_state->arena, len);
				memcpy(e.original_title, original_title, len);
			}

			if (ex_buf_len(split_buf))
			{
				ex_buf_push(split_buf, NULL); //terminator
				size_t len = ex_buf_sizeof(split_buf);
				e.split = (explore_string_t **)ex_arena_alloc(&explore_state->arena, len);
				memcpy(e.split, split_buf, len);
				ex_buf_clear(split_buf);
			}

			ex_buf_push(explore_state->entries, e);
		}
		libretrodb_cursor_close(cur);
		libretrodb_cursor_free(cur);
		libretrodb_close(rdb->handle);
		libretrodb_free(rdb->handle);
		ex_hashmap32_free(&rdb->playlist_entries);
	}
	ex_buf_free(split_buf);
	ex_hashmap32_free(&map_cores);
	ex_hashmap32_free(&rdb_indices);
	ex_buf_free(rdbs);

	for (int i = 0; i != EXPLORE_CAT_COUNT; i++)
	{
		size_t len = ex_buf_len(explore_state->by[i]);
		qsort(explore_state->by[i], len, sizeof(*explore_state->by[i]), explore_qsort_func_strings);
		for (uint32_t idx = 0; idx != len; idx++)
			explore_state->by[i][idx]->idx = idx;

		ex_hashmap32_free(&cat_maps[i]);
	}
	qsort(explore_state->entries, ex_buf_len(explore_state->entries), sizeof(*explore_state->entries), explore_qsort_func_entries);
}

static int explore_action_get_title(const char *path, const char *label, unsigned menu_type, char *s, size_t len)
{
	snprintf(s, len, "%s", explore_state->title);
	return 0;
}

static void explore_append_title(const char* fmt, ...)
{
	va_list ap;
	size_t len = strlen(explore_state->title);
	va_start(ap, fmt);
	vsnprintf(explore_state->title + len, sizeof(explore_state->title) - len, fmt, ap);
	va_end(ap);
}

static int explore_action_sublabel_spacer(file_list_t *list, unsigned type, unsigned i, const char *label, const char *path, char *s, size_t len)
{
	strlcpy(s, " ", len);
	return 1; // 1 means it'll never change and can be cached
}

static int explore_action_ok(const char *path, const char *label, unsigned type, size_t idx, size_t entry_idx)
{
	const char* explore_tab = msg_hash_to_str(MENU_ENUM_LABEL_EXPLORE_TAB);
	filebrowser_clear_type();
	return generic_action_ok_displaylist_push(explore_tab, NULL, explore_tab, type, idx, entry_idx, ACTION_OK_DL_PUSH_DEFAULT);
}

static menu_file_list_cbs_t* explore_menu_entry(file_list_t *list, const char *path, unsigned type)
{
	menu_entries_append_enum(list, path, explore_state->label_explore_item_str, MENU_ENUM_LABEL_EXPLORE_ITEM, type, 0, 0);
	menu_file_list_cbs_t* cbs = ((menu_file_list_cbs_t*)list->list[list->size-1].actiondata);
	cbs->action_ok = explore_action_ok;
	return cbs;
}

static void explore_menu_add_spacer(file_list_t *list)
{
	if (!list->size) return;
	((menu_file_list_cbs_t*)list->list[list->size-1].actiondata)->action_sublabel = explore_action_sublabel_spacer;
}

static void explore_action_find_complete(void *userdata, const char *line)
{
	menu_input_dialog_end();
	if (line && *line)
	{
		strlcpy(explore_state->find_string, line, sizeof(explore_state->find_string));
		explore_action_ok(NULL, NULL, EXPLORE_TYPE_SEARCH, 0, 0);
	}
}

static int explore_action_ok_find(const char *path, const char *label, unsigned type, size_t idx, size_t entry_idx)
{
	menu_input_ctx_line_t line = {0};
	line.label = "Search Text";
	line.cb = explore_action_find_complete;
	menu_input_dialog_start(&line);
	return 0;
}

unsigned menu_displaylist_explore(file_list_t *list)
{
	char tmp[512];
	file_list_t *menu_stack = menu_entries_get_menu_stack_ptr(0);

	if (!explore_state)
	{
		explore_build_list();
		explore_state->top_depth = (unsigned)menu_stack->size - 1;
	}

	if (menu_stack->size > 1)
	{
		struct item_file *stack = &menu_stack->list[menu_stack->size - 1];
		menu_file_list_cbs_t* cbs = ((menu_file_list_cbs_t*)stack->actiondata);
		cbs->action_get_title = explore_action_get_title;
	}

	struct item_file *stack_top = menu_stack->list + explore_state->top_depth;
	unsigned depth = (unsigned)menu_stack->size - 1 - explore_state->top_depth;
	unsigned current_type = stack_top[depth].type;
	unsigned current_cat = current_type - EXPLORE_TYPE_FIRSTCATEGORY;
	unsigned previous_cat = stack_top[depth ? depth - 1 : 0].type - EXPLORE_TYPE_FIRSTCATEGORY;

	if (depth)
	{
		((menu_file_list_cbs_t*)stack_top[depth].actiondata)->action_get_title = explore_action_get_title;

		bool clear_find_text = (current_type != EXPLORE_TYPE_SEARCH);
		explore_state->title[0] = '\0';
		for (unsigned i = 1, levels = 0; i < depth; i++)
		{
			unsigned by_category = (stack_top[i].type - EXPLORE_TYPE_FIRSTCATEGORY);
			if (stack_top[i].type == EXPLORE_TYPE_SEARCH) clear_find_text = false;
			if (by_category >= EXPLORE_CAT_COUNT) continue;

			unsigned by_selected_type = stack_top[i + 1].type;
			const char* name = explore_by_info[by_category].name;
			explore_string_t **entries = explore_state->by[by_category];
			explore_append_title("%s%s: %s", (levels++ ? " / " : ""), name, (by_selected_type != EXPLORE_TYPE_FILTERNULL ? entries[by_selected_type - EXPLORE_TYPE_FIRSTITEM]->str : "Unknown"));
		}

		if (clear_find_text)
			explore_state->find_string[0] = '\0';

		if (*explore_state->find_string)
			explore_append_title(" '%s'", explore_state->find_string);
	}

	void playlist_set_cached(playlist_t* pl);
	playlist_set_cached(NULL);

	if (current_type == MENU_EXPLORE_TAB || current_type == EXPLORE_TYPE_ADDITIONALFILTER)
	{
		// Explore top or selecting an additional filter
		bool is_top = (current_type == MENU_EXPLORE_TAB);
		if (is_top) strlcpy(explore_state->title, "Explore", sizeof(explore_state->title));
		else explore_append_title(" - Additional Filter");

		if (is_top || !*explore_state->find_string)
		{
			explore_menu_entry(list, "Search Name ...", EXPLORE_TYPE_SEARCH)->action_ok = explore_action_ok_find;
			explore_menu_add_spacer(list);
		}

		for (unsigned cat = 0; cat < EXPLORE_CAT_COUNT; cat++)
		{
			const char* name = explore_by_info[cat].name;
			explore_string_t **entries = explore_state->by[cat];
			if (!ex_buf_len(entries)) continue;

			for (unsigned i = 1; i < depth; i++)
				if (stack_top[i].type == cat + EXPLORE_TYPE_FIRSTCATEGORY)
					goto SKIP_EXPLORE_BY_CATEGORY;

			if (!is_top)
				snprintf(tmp, sizeof(tmp), "By %s", name);
			else if (explore_by_info[cat].is_numeric)
				snprintf(tmp, sizeof(tmp), "By %s (%s - %s)", name, entries[0]->str, entries[ex_buf_len(entries) - 1]->str);
			else
				snprintf(tmp, sizeof(tmp), "By %s (%u entries)", name, (unsigned)ex_buf_len(entries));
			explore_menu_entry(list, tmp, cat + EXPLORE_TYPE_FIRSTCATEGORY);

			SKIP_EXPLORE_BY_CATEGORY:;
		}

		if (is_top)
		{
			explore_menu_add_spacer(list);
			explore_menu_entry(list, "Show All", EXPLORE_TYPE_SHOWALL);
		}
	}
	else if (depth == 1 && current_type != EXPLORE_TYPE_SEARCH && current_type != EXPLORE_TYPE_SHOWALL)
	{
		// List all items in a selected explore by category
		explore_string_t **entries = explore_state->by[current_cat];
		for (int i = 0, i_last = ex_buf_len(entries) - 1; i <= i_last; i++)
			explore_menu_entry(list, entries[i]->str, EXPLORE_TYPE_FIRSTITEM + i);
		if (explore_state->has_unknown[current_cat])
		{
			explore_menu_add_spacer(list);
			explore_menu_entry(list, "Unknown", EXPLORE_TYPE_FILTERNULL);
		}
		explore_append_title("Select %s", explore_by_info[current_cat].name);
	}
	else if (previous_cat < EXPLORE_CAT_COUNT || current_type < EXPLORE_TYPE_FIRSTITEM)
	{
		unsigned levels = 0;
		unsigned cats[10];
		explore_string_t* filter[10];
		bool use_split[10];
		bool use_find = (*explore_state->find_string != '\0');

		bool is_show_all = (depth == 1 && !use_find);
		bool is_filtered_category = (current_cat < EXPLORE_CAT_COUNT);
		bool filtered_category_have_unknown = false;

		if (is_filtered_category)
		{
			// List filtered items in a selected explore by category
			explore_append_title(" - Select %s", explore_by_info[current_cat].name);
		}
		else
		{
			// Game list
			if (is_show_all)
			{
				explore_append_title("All");
				explore_menu_entry(list, "Search Name ...", EXPLORE_TYPE_SEARCH)->action_ok = explore_action_ok_find;
			}
			else
				explore_menu_entry(list, "Add Additional Filter", EXPLORE_TYPE_ADDITIONALFILTER);
			explore_menu_add_spacer(list);
		}

		for (unsigned i = 1; i < depth; i++)
		{
			unsigned by_category = (stack_top[i].type - EXPLORE_TYPE_FIRSTCATEGORY);
			if (by_category >= EXPLORE_CAT_COUNT) continue;

			unsigned by_selected_type = stack_top[i + 1].type;
			explore_string_t **entries = explore_state->by[by_category];
			cats     [levels] = by_category;
			use_split[levels] = explore_by_info[by_category].use_split;
			filter   [levels] = (by_selected_type == EXPLORE_TYPE_FILTERNULL ? NULL : entries[by_selected_type - EXPLORE_TYPE_FIRSTITEM]);
			levels++;
		}

		ex_hashmap32 map_filtered_category = {0};
		for (explore_entry_t *e = explore_state->entries, *e_end = ex_buf_end(explore_state->entries); e != e_end; e++)
		{
			for (unsigned lvl = 0; lvl != levels; lvl++)
			{
				if (filter[lvl] == e->by[cats[lvl]]) continue;
				if (use_split[lvl] && e->split)
				{
					explore_string_t** split = e->split;
					do { if (*split == filter[lvl]) break; } while (*(++split));
					if (*split) continue;
				}
				goto SKIP_ENTRY;
			}

			if (use_find && !strcasestr(e->playlist_entry->label, explore_state->find_string))
				goto SKIP_ENTRY;

			if (is_filtered_category)
			{
				explore_string_t* str = e->by[current_cat];
				if (!str) { filtered_category_have_unknown = true; continue; }
				if (ex_hashmap32_getnum(&map_filtered_category, str->idx + 1)) continue;
				ex_hashmap32_setnum(&map_filtered_category, str->idx + 1, 1);
				explore_menu_entry(list, str->str, EXPLORE_TYPE_FIRSTITEM + str->idx);
			}
			else
			{
				explore_menu_entry(list, (e->original_title ? e->original_title : e->playlist_entry->label), EXPLORE_TYPE_FIRSTITEM + (e - explore_state->entries));
			}

			SKIP_ENTRY:;
		}

		if (is_filtered_category)
			qsort(list->list, list->size, sizeof(*list->list), explore_qsort_func_menulist);

		if (is_filtered_category && filtered_category_have_unknown)
		{
			explore_menu_add_spacer(list);
			explore_menu_entry(list, "Unknown", EXPLORE_TYPE_FILTERNULL);
		}

		explore_append_title(" (%u)", (unsigned) (list->size - 1));
	}
	else
	{
		// Content page of selected game
		const struct playlist_entry *pl_entry = explore_state->entries[current_type - EXPLORE_TYPE_FIRSTITEM].playlist_entry;

		snprintf(explore_state->title, sizeof(explore_state->title), "%s", pl_entry->label);

		for (int pl_idx = 0; pl_idx != ex_buf_len(explore_state->playlists); pl_idx++)
		{
			playlist_t* pl = explore_state->playlists[pl_idx];
			const struct playlist_entry* pl_first;
			playlist_get_index(pl, 0, &pl_first);
			if (pl_entry < pl_first || pl_entry >= pl_first + playlist_size(pl))
				continue;

			// Fake all the state so the content screen and information screen think we're viewing via playlist
			playlist_set_cached(pl);
			menu_handle_t *menu = menu_driver_get_ptr();
			menu->rpl_entry_selection_ptr = (pl_entry - pl_first);
			strlcpy(menu->deferred_path, pl_entry->path, sizeof(menu->deferred_path));

			menu_displaylist_info_t info = {0};
			info.list = list;
			menu_displaylist_ctl(DISPLAYLIST_HORIZONTAL_CONTENT_ACTIONS, &info);
			break;
		}
	}

	return list->size;
}