/** Run with a `kjv` sub-directory. Two functionaries: counts all words from
 verses <https://github.com/scrollmapper/bible_databases/master/txt/KJV/>
 dynamically and puts them into an unchanging `kjvcount_table` on initialisation.
 Then has a set to each of the verses, `kjvset`, which starts off empty.
 @license 2022 Neil Edelman, distributed under the terms of the
 [MIT License](https://opensource.org/licenses/MIT). Uses the KJV at
 [bible databases](https://github.com/scrollmapper/bible_databases/tree/master),
 "All included Bible translations are in the public domain."
 @std C11 */

#include "../src/kjv.h"
#include "../src/pair.h"
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <dirent.h> /* opendir readdir closedir */
#include <unistd.h> /* chdir (POSIX) (because I'm lazy) */


void kjvcite_to_string(const union kjvcite x, char (*const a)[12])
	{ sprintf(*a, "%.4s%" PRIu32 ":%" PRIu32,
	kjv_book_string[x.book < KJV_BOOK_SIZE ? x.book : KJV_BOOK_SIZE],
	x.chapter % 1000, x.verse % 1000); }

/* Reversible hash map. */
/** <https://nullprogram.com/blog/2018/07/31/>
 <https://github.com/skeeto/hash-prospector> on `x`. */
static uint32_t lowbias32(uint32_t x) {
	x ^= x >> 16;
	x *= 0x7feb352dU;
	x ^= x >> 15;
	x *= 0x846ca68bU;
	x ^= x >> 16;
	return x;
}
/* Inverts `x`. */
static uint32_t lowbias32_r(uint32_t x) {
	x ^= x >> 16;
	x *= 0x43021123U;
	x ^= x >> 15 ^ x >> 30;
	x *= 0x1d69e2a5U;
	x ^= x >> 16;
	return x;
}

/* Set of verses. */
static uint32_t kjvset_hash(const union kjvcite x) { return lowbias32(x.u32); }
static union kjvcite kjvset_unhash(const uint32_t x)
	{ union kjvcite k; k.u32 = lowbias32_r(x); return k; }
static void kjvset_to_string(const union kjvcite x, char (*const a)[12])
	{ kjvcite_to_string(x, a); }
#define TABLE_NAME kjvset
#define TABLE_KEY union kjvcite
#define TABLE_UINT uint32_t
#define TABLE_UNHASH
#define TABLE_TO_STRING
#define TABLE_BODY
#include "../src/table.h"

/* Derived information on verse word count. */
static uint32_t kjvcount_hash(const union kjvcite x) { return kjvset_hash(x); }
static union kjvcite kjvcount_unhash(const uint32_t x)
	{ return kjvset_unhash(x); }
static void kjvcount_to_string(const union kjvcite x, const unsigned count,
	char (*const a)[12]) { (void)count; kjvcite_to_string(x, a); }
#define TABLE_NAME kjvcount
#define TABLE_KEY union kjvcite
#define TABLE_UINT uint32_t
#define TABLE_VALUE unsigned /* Count words. */
#define TABLE_UNHASH
#define TABLE_DEFAULT 0
#define TABLE_TO_STRING
#define TABLE_BODY
#include "../src/table.h"


/* Parse filename of books. */
/*!re2c /**/
re2c:yyfill:enable = 0;
re2c:define:YYCTYPE = char;
natural = [1-9][0-9]*;
whitespace = [ \t\v\f];
word = [^ \t\v\f\n\x00]+;
*/
/** `fn` contains "<number>[*].txt", sticks that in `book_no`, otherwise
 returns false. */
static int looks_like_book_fn(const char *fn, unsigned *const book_no) {
	const char *YYCURSOR = fn, *YYMARKER, *yyt1, *yyt2, *s0, *s1;
	assert(fn && book_no);
	/*!re2c /**/
	*
		{ return 0; }
	@s0 natural @s1 [^.\x00]* ".txt" "\x00"
		{ return pair_to_natural(s0, s1, book_no); }
	*/
}


/* This is the contents of the <fn:looks_like_book_fn>. */
struct lex {
	size_t line;
	const char *cursor;
	int error;
	uint32_t chapter, verse, words;
};
static struct lex lex(const char *cursor) {
	struct lex lex;
	assert(cursor);
	lex.line = 1;
	lex.cursor = cursor;
	lex.error = 0;
	lex.chapter = lex.verse = lex.words = 0;
	return lex;
}
/*!conditions:re2c*/
static int lex_next_verse(struct lex *const lex) {
	const char *YYMARKER, *yyt1 = 0, *yyt2 = 0, *s0, *s1, *t0, *t1;
	enum YYCONDTYPE condition = yycline;
	/*!re2c /**/
	re2c:define:YYCURSOR = lex->cursor;
	re2c:define:YYGETCONDITION = "condition";
	re2c:define:YYSETCONDITION = "condition = @@;";
	re2c:define:YYGETCONDITION:naked = 1;
	re2c:define:YYSETCONDITION:naked = 1; */
	assert(lex && lex->cursor);
	lex->error = 0;
scan:
	/*!re2c /**/
	<*> * { return errno = EILSEQ, lex->error = 1, 0; }
	<line> [^[\]\n\x00]* "\n" { lex->line++; goto scan; }
	<line> "\x00" { return 0; }
	<line> "[" @s0 natural @s1 ":" @t0 natural @t1 "]" => verse {
		if(!pair_to_natural(s0, s1, &lex->chapter)
			|| !pair_to_natural(t0, t1, &lex->verse))
			return errno = EILSEQ, lex->error = 1, 0;
		lex->words = 0;
		/*printf("%u:%u", lex->chapter, lex->verse);*/
		goto scan;
	}
	<verse> whitespace+ { goto scan; }
	<verse> @s0 word @s1 { lex->words++; goto scan; }
	<verse> "\n" { /*printf(" -> %u\n", lex->words);*/ lex->line++; return 1; }
	*/
}

/* KJV count -- loaded up on initialization and is static for it's lifetime.
 Given the verse citation, how many words does it have? */
/** Frees `count`. */
void kjv_count_(struct kjvcount_table *const count) { kjvcount_table_(count); }
/** Loads 66 files from the "kjv/" directory and counts all the words, which
 are stored in `total`. `total` is zero if an error occurred, in which case the
 details are sent to `stderr` and `errno` is set. @return On success, a
 `kjvcount_table` that maps citations to word count. */
struct kjvcount_table kjv_count(size_t *const total) {
	const char *const dir_kjv = "kjv";
	struct char_array backing = text();
	struct kjvcount_table count = kjvcount_table();
	DIR *dir = 0;
	struct dirent *de = 0;
	struct { size_t offset; int is; } build[KJV_BOOK_SIZE] = { 0 };
	enum kjv_book b = 0;
	int is_in_kjv = 0;

	assert(total);
	*total = 0;
	/* For all files in directory KJV with <#>*.txt, read into backing. */
	if(chdir(dir_kjv) == -1 || (is_in_kjv = 1, !(dir = opendir("."))))
		goto catch;
	while((de = readdir(dir))) {
		unsigned ordinal;
		char *unstable_backing;
		if(!looks_like_book_fn(de->d_name, &ordinal)) continue;
		/*fprintf(stderr, "<%s> ordinal: %u\n", de->d_name, ordinal);*/
		if(ordinal < 1 || ordinal > KJV_BOOK_SIZE)
			{ errno = ERANGE; goto catch; } /* Not in range. */
		if(build[b = ordinal - 1].is) /* Convert to zero-based. */
			{ errno = EDOM; goto catch; } /* Is duplicate. */
		if(!(unstable_backing = text_append_file(&backing, de->d_name)))
			goto catch;
		build[b].is = 1;
		build[b].offset = (size_t)(unstable_backing - backing.data);
	}
	if(closedir(dir) == -1) { dir = 0; goto catch; } dir = 0;

	/* Now backing is stable; count all the words for each verse. */
	for(b = 0; b < KJV_BOOK_SIZE; b++) {
		struct lex x;
		if(!build[b].is) { fprintf(stderr, "Missing book [%u]%s.\n",
			b + 1, kjv_book_string[b]); errno = EDOM; goto catch; }
		x = lex(backing.data + build[b].offset);
		while(lex_next_verse(&x)) {
			const union kjvcite cite
				= { .book = b, .chapter = x.chapter, .verse = x.verse };
			unsigned *words;
			switch(kjvcount_table_assign(&count, cite, &words)) {
			case TABLE_PRESENT: fprintf(stderr, "[%u]%s %u:%u duplicated.\n",
				b + 1, kjv_book_string[b], x.chapter, x.verse); errno = EDOM;
			case TABLE_ERROR: goto catch;
			case TABLE_ABSENT: break;
			}
			*words = x.words, *total += x.words;
		}
		if(x.error) { fprintf(stderr, "[%u]%s on line %zu\n",
			b + 1, kjv_book_string[b], x.line); goto catch; }
	}
	goto finally;
catch:
	*total = 0;
	if(de) fprintf(stderr, "While reading %s/%s.\n", dir_kjv, de->d_name);
	else fprintf(stderr, "In directory %s/.\n", dir_kjv);
recatch:
	kjv_count_(&count);
finally:
	if(dir) { if(closedir(dir)) { dir = 0; goto recatch; } dir = 0; }
	if(is_in_kjv && (is_in_kjv = 0, chdir("..") == -1)) goto recatch;
	text_(&backing);
	return count;
}
size_t kjv_count_get(struct kjvcount_table *const count,
	const union kjvcite cite) { return kjvcount_table_get(count, cite); }
const char *kjv_count_to_string(const struct kjvcount_table *const count)
	{ return kjvcount_table_to_string(count); }

/* KJV set -- keeps track of membership by verse. */
struct kjvset_table kjv_set(void) { return kjvset_table(); }
void kjv_set_(struct kjvset_table *const set) { kjvset_table_(set); }
enum table_result kjv_set_add(struct kjvset_table *const set,
	const union kjvcite cite) { return kjvset_table_try(set, cite); }
const char *kjv_set_to_string(const struct kjvset_table *const set)
	{ return set ? kjvset_table_to_string(set) : 0; }