/** @std GNU C11 */

#include "lex.h"
#include <unistd.h> /* chdir (POSIX) */
#include <sys/types.h> /* mode_t (POSIX) */
#include <sys/stat.h> /* umask (POSIX) */
#include <dirent.h> /* opendir readdir closedir */
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>

#if INT_MAX >= 100000000000
#error int_to_string requires truncation on this compiler.
#endif
static void int_to_string(const int *const n,
	char (*const a)[12]) { sprintf(*a, "%d", *n); }
#define ARRAY_NAME int
#define ARRAY_TYPE int
#define ARRAY_EXPECT_TRAIT
#include "array.h"
#define ARRAY_TO_STRING &int_to_string
#include "array.h"
static int int_cmp(const int *const a, const int *const b)
	{ return (*b < *a) - (*a < *b); }
static int void_int_cmp(const void *const a, const void *const b)
	{ return int_cmp(a, b); }

#define ARRAY_NAME char
#define ARRAY_TYPE char
#include "array.h"
/** Append a text file, `fn`, to `c`, and add a '\0'.
 @return Success. A partial read is failure. @throws[fopen, fread, malloc]
 @throws[EISEQ] The text file has embedded nulls.
 @throws[ERANGE] If the standard library does not follow POSIX. */
static int append_file(struct char_array *c, const char *const fn) {
	FILE *fp = 0;
	const size_t granularity = 1024;
	size_t nread;
	char *cursor;
	int success = 0;
	assert(c && fn);
	if(!(fp = fopen(fn, "r"))) goto catch;
	/* Read entire file in chunks. */
	do if(!(cursor = char_array_buffer(c, granularity))
		|| (nread = fread(cursor, 1, granularity, fp), ferror(fp))
		|| !char_array_append(c, nread)) goto catch;
	while(nread == granularity);
	/* File to `C` string. */
	if(!(cursor = char_array_new(c))) goto catch;
	*cursor = '\0';
	/* Binary files with embedded '\0' are not allowed. */
	if(strchr(c->data, '\0') != cursor) { errno = EILSEQ; goto catch; }
	{ success = 1; goto finally; }
catch:
	if(!errno) errno = EILSEQ; /* Will never be true on POSIX. */
finally:
	if(fp && fclose(fp)) success = 0;
	return success;
}

/** Is `y` a leap-year? */
static int leap(int y) {
	assert(y >= 1582);
	if(!(y % 400)) return 1;
	if(!(y % 100)) return 0;
	if(!(y % 4)) return 1;
	return 0;
}
/** Not defined for some implementations. C11 */
union date32 {
	uint32_t u32;
	struct { unsigned day : 5, month : 4, year : 23; };
};
static int date_mixup(union date32 a, union date32 b) { return a.u32 > b.u32; }
static void date32_to_string(const union date32 d, char (*const z)[12]) {
	assert(d.year < 10000 && d.month && d.month <= 31 && d.day && d.day <= 31);
	sprintf(*z, "%u-%2.2u-%2.2u", d.year % 10000, d.month, d.day);
}

/** Convert or narrower type or return zero. */
static union date32 date_to_32(const int y, const int m, const int d) {
	union date32 d32 = { 0 };
	/* Leap year calculations only work at y>=1 and Gregorian Calendar and max
	 23 bits. */
	if(y < 1582 || y > 8388607 || m < 1 || m > 12 || d < 1 || d > 31)
		goto no;
	switch(m) {
	case 1: case 3: case 5: case 7: case 8: case 10: case 12: break;
	case 4: case 6: case 9: case 11: if(d > 30) goto no; break;
	case 2: if(d > 28 + leap(y)) goto no; break;
	default: assert(0); break;
	}
	d32.year = (unsigned)y, d32.month = (unsigned)m, d32.day = (unsigned)d;
no:
	return d32;
}

/** Tomohiko Sakamoto comp.lang.c 1993-04-10. */
static unsigned weekday(union date32 d) {
	d.year -= d.month < 3;
	return (d.year + d.year / 4 - d.year / 100 + d.year / 400
		+ "-bed=pen+mad."[d.month] + d.day) % 7;
}


#define ARRAY_NAME lex
#define ARRAY_TYPE struct lex
#include "array.h"
struct page_tree_entry_c;
static void entry_to_string(struct page_tree_entry_c, char (*)[12]);
struct page {
	struct char_array entry;
	struct lex_array lexx;
};
#define TREE_NAME page
#define TREE_KEY union date32
#define TREE_VALUE struct page
#define TREE_COMPARE &date_mixup
#define TREE_EXPECT_TRAIT
#include "tree.h"
#define TREE_TO_STRING &entry_to_string
#include "tree.h"
static void entry_to_string(const struct page_tree_entry_c entry,
	char (*const z)[12]) { date32_to_string(*entry.key, z); }

struct source { char *key, *desc; };

int main(int argc, char **argv) {
	int success = EXIT_SUCCESS;

	/* For reading in files, overwritten. */
	DIR *dir = 0;
	struct dirent *de;
	struct int_array years = int_array(), months = int_array(),
		days = int_array();
	int *y, *y_end;

	struct page_tree journal = page_tree();

	errno = 0;
	if(argc != 2) { fprintf(stderr, "Needs journal location.\n"
		"(should contain <year>/<month>/<day>.txt)\n"); goto finally; }

	/* Get the years list as directories matching a year. */
	if(chdir(argv[1]) == -1 || !(dir = opendir("."))) goto catch;
	while((de = readdir(dir))) {
		struct stat st;
		int year, *p;
		if(!lex_looks_like_year(de->d_name, &year)) continue;
		if(stat(de->d_name, &st)) goto catch;
		if(!S_ISDIR(st.st_mode)) continue;
		if(!(p = int_array_new(&years))) goto catch;
		*p = year;
	}
	closedir(dir), dir = 0;
	/* Sort the years for sensible ordering of parsing. */
	qsort(years.data, years.size, sizeof *years.data, &void_int_cmp);
	fprintf(stderr, "Files in %s: %s.\n", argv[1], int_array_to_string(&years));

	/* Go though each year. */
	for(y = years.data, y_end = y + years.size; y < y_end; y++) {
		char fn[64];
		int *m, *m_end;
		sprintf(fn, "%d", *y);

		/* Get the months as directories. */
		if(chdir(fn) == -1 || !(dir = opendir("."))) goto catch;
		while((de = readdir(dir))) {
			struct stat st;
			int month, *p;
			if(!(month = lex_looks_like_month(de->d_name))) continue;
			if(stat(de->d_name, &st)) goto catch;
			if(!S_ISDIR(st.st_mode)) continue;
			if(!(p = int_array_new(&months))) goto catch;
			*p = month;
		}
		closedir(dir), dir = 0;
		qsort(months.data, months.size, sizeof *months.data, &void_int_cmp);
		fprintf(stderr, "Files in %s: %s.\n",
			fn, int_array_to_string(&months));

		/* Go though each month. */
		for(m = months.data, m_end = m + months.size; m < m_end; m++) {
			int *d, *d_end;
			sprintf(fn, "%.2d", *m);
			printf("month %s\n", fn);

			/* Get the days as files. */
			if(chdir(fn) == -1 || !(dir = opendir("."))) goto catch;
			while((de = readdir(dir))) {
				struct stat st;
				int day, *p;
				/* fixme: Have yyyy-mm-dd to figure out how many days. */
				if(!(day = lex_looks_like_day(de->d_name))) continue;
				if(stat(de->d_name, &st)) goto catch;
				if(S_ISDIR(st.st_mode)) continue;
				if(!(p = int_array_new(&days))) goto catch;
				*p = day;
			}
			closedir(dir), dir = 0;
			qsort(days.data, days.size, sizeof *days.data, &void_int_cmp);
			fprintf(stderr, "Files in %s: %s.\n",
				fn, int_array_to_string(&days));

			for(d = days.data, d_end = d + days.size; d < d_end; d++) {
				union date32 d32;
				struct page *page = 0;
				printf("Date: %d-%.2d-%.2d\n", *y, *m, *d);
				if(!(d32 = date_to_32(*y, *m, *d)).year)
					{ errno = EILSEQ; goto catch; }
				sprintf(fn, "%.2d.txt", *d);
				if(page_tree_bulk_add(&journal, d32, &page) != TREE_UNIQUE) {
					if(!errno) fprintf(stderr, "Not unique?\n"), errno = EDOM;
					goto catch;
				}
				page->entry = char_array();
				page->lexx = lex_array();
				if(!append_file(&page->entry, fn)) goto catch;
				printf("%s", page->entry.data);
				printf("Lexing:\n");
				for(lex_reset(page->entry.data); ; ) {
					struct lex *lex;
					if(!(lex = lex_array_new(&page->lexx))) goto catch;
					if(!lex_next(lex)) {
						if(lex->symbol != END) { errno = EILSEQ; goto catch; }
						printf("Lexing finished: %s on %lu.\n",
							lex_symbols[lex->symbol], lex->line);
						break;
					}
					printf("%lu: %s",
						(unsigned long)lex->line, lex_symbols[lex->symbol]);
					if(lex->symbol == TEXT || lex->symbol == ARG_KEYWORD
						|| lex->symbol == ARG_DATE
						|| lex->symbol == ARG_FREEFORM
						|| lex->symbol == CAPTION) {
						if(lex->s0 + INT_MAX < lex->s1)
							{ errno = EILSEQ; goto catch; }
						printf(" <<%.*s>>", (int)(lex->s1 - lex->s0), lex->s0);
					}
					printf(".\n");
				}
				/* Transfer the temporary page to the journal. */
				page = 0;
			}

			int_array_clear(&days);
			if(chdir("..") == -1) goto catch;
		}

		int_array_clear(&months);
		if(chdir("..") == -1) goto catch;
		break; /* fixme */
	}
	page_tree_bulk_finish(&journal);
	printf("Journal has entries: %s\n", page_tree_to_string(&journal));
	goto finally;
catch:
	success = EXIT_FAILURE;
	perror("interpret");
finally:
	if(dir && closedir(dir)) success = EXIT_FAILURE, perror("dir");
	int_array_(&years);
	int_array_(&months);
	int_array_(&days);
	struct page_tree_entry entry;
	for(struct page_tree_iterator it = page_tree_begin(&journal);
		(entry = page_tree_next(&it)).key; ) {
		struct page *const page = entry.value;
		char z[12];
		date32_to_string(*entry.key, &z);
		printf("Freeing %s.\n", z);
		lex_array_(&page->lexx);
		char_array_(&page->entry);
	}
	return success;
}

/* Popular KJV 738137 words. */