#define _POSIX_C_SOURCE 200809L
#include <string.h>

#include "zpm.h"
#include "sqlite3.h"
#include "sha256.h"

static void hash_byte(struct sha256_state *h, int ch) {
	unsigned char buf[1];

	buf[0] = ch & 0xff;
	sha256_process(h, buf, 1);
}

/* i will be positive, we are hashing column sizes */
static void hash_int(struct sha256_state *h, int i) {
	int n;
	uint64_t z;

	z = i;

	n = sizeof i;
	while (n--) {
		hash_byte(h, (int)(z & 0xff));
		z = z>>8;
	}
}

/*
 * Implementation of the sha3_query(SQL,SIZE) function.
 *
 * This function compiles and runs the SQL statement(s) given in the argument.
 * The results are hashed using a SIZE-bit SHA3.  The default size is 256.
 *
 * The format of the byte stream that is hashed is summarized as follows:
 *
 *       R
 *       N
 *       I<int>
 *       F<ieee-float>
 *       B<size>:<bytes>
 *       T<size>:<text>
 *
 * <sql> is the original SQL text for each statement run and <n> is the size of
 * that text.  The SQL text is UTF-8.  A single R character occurs before the
 * start of each row.  N means a NULL value.  I mean an 8-byte little-endian
 * integer <int>.  F is a floating point number with an 8-byte little-endian
 * IEEE floating point value <ieee-float>.  B means blobs of <size> bytes.  T
 * means text rendered as <size> bytes of UTF-8.  The <size> values are
 * expressed as little endian 8 byte integers.
 *
 * 
 * There are zero or more R segments, one for each row in the
 * result set.  After each R, there are one or more N, I, F, B, or T segments,
 * one for each column in the result set.  Segments are concatentated directly
 * with no delimiters of any kind.
 */

static void hash_query(struct zpm *zpm, const char *zSql, struct sha256_state *h) {
	sqlite3 *db;
	sqlite3_stmt *pStmt = 0;
	int nCol; /* Number of columns in the result set */
	int i, rc;

	const unsigned char *data;
	int bytes;

	double r;
	sqlite3_uint64 u;
	sqlite3_int64 v;
	int j;
	unsigned char x[9];

	if (!zSql) return;
	if (!zpm) return;

	db = zpm->db;

	rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, &zSql);
	if (rc) {
		zpm->dberrmsg = strdup(sqlite3_errmsg(db));
		sqlite3_finalize(pStmt);
		return;
	}

	nCol = sqlite3_column_count(pStmt);

	while (sqlite3_step(pStmt) == SQLITE_ROW) {
		sha256_process(h, (const unsigned char *)"R", 1);
		for (i = 0; i < nCol; i++) {
			switch (sqlite3_column_type(pStmt, i)) {
				case SQLITE_NULL:
					hash_byte(h, 'N');
					continue;
				       	break;
				case SQLITE_INTEGER:
					v = sqlite3_column_int64(pStmt, i);
					memcpy(&u, &v, 8);
					for (j = 8; j >= 1; j--) {
						x[j] = u & 0xff;
						u >>= 8;
					}
					x[0] = 'I';
					data = x;
					bytes = 9;
					break;
				case SQLITE_FLOAT:
					r = sqlite3_column_double(pStmt, i);
					memcpy(&u, &r, 8);
					for (j = 8; j >= 1; j--) {
						x[j] = u & 0xff;
						u >>= 8;
					}
					x[0] = 'F';
					data = x;
					bytes = 9;
					break;
				case SQLITE_TEXT:
					bytes = sqlite3_column_bytes(pStmt, i);
					data = sqlite3_column_text(pStmt, i);
					hash_byte(h, 'T');
					hash_int(h, bytes);
					break;
				case SQLITE_BLOB:
					bytes = sqlite3_column_bytes(pStmt, i);
					data = sqlite3_column_blob(pStmt, i);
					hash_byte(h, 'B');
					hash_int(h, bytes);
					break;
				default:
					hash_byte(h, 'U');
					continue;
				       	break;
			}
			sha256_process(h, data, bytes);
		}
	}
	sqlite3_finalize(pStmt);
}

int zpm_package_hash(struct zpm *zpm, char *pkgid, char *hash) {
	struct sha256_state d;
	char *sql;
	int i;
	unsigned char tmp[32];

	if (!hash) {
		return 0;
	}

	sha256_init(&d);
	/* find package */

	sql = sqlite3_mprintf("select package,version,release,description,architecture,url,licenses,packager,build_time from packages_pkgid where pkgid = %Q", pkgid);

	hash_query(zpm, sql, &d);
	sqlite3_free(sql);

	/* hash package files */

	sql = sqlite3_mprintf("select path, mode, username, groupname, configuration, "
		"filetype, target, device, mtime, hash "
		"from packagefiles_pkgid where pkgid = %Q order by path",
		pkgid);
	hash_query(zpm, sql, &d);
	sqlite3_free(sql);

	sha256_done(&d, tmp);
	for (i=0; i<32; i++) {
		sprintf(hash+i*2, "%02x", (unsigned)tmp[i]);
	}
	hash[64] = 0;

	return 1;

}

int zpm_package_sethash(struct zpm *zpm, char *pkgid, char *hash) {
	char buf[ZPM_HASH_STRLEN + 1];
	char *sql;

	if (!hash) {
		hash = buf;
	}

	zpm_package_hash(zpm, pkgid, hash);

	sql = sqlite3_mprintf("update packages_pkgid set hash = %Q where pkgid = %Q", hash, pkgid);

	zpm_exec(zpm, sql, NULL, NULL, NULL);
	sqlite3_free(sql);

	return 1;
}