#include <stdbool.h>

#include "package_info.h"

PkgInfo *package_info_init() {
	return calloc(1, sizeof(PkgInfo));
}

void package_info_free(PkgInfo *pkg_info) {
	FREE_STRING(pkg_info->name);
	FREE_STRING(pkg_info->base);
	FREE_STRING(pkg_info->version);
	FREE_STRING(pkg_info->description);
	FREE_STRING(pkg_info->url);
	FREE_STRING(pkg_info->arch);
	FREE_STRING(pkg_info->packager);
	FREE_STRING(pkg_info->pgpsig);

	dynarray_free(pkg_info->groups);
	dynarray_free(pkg_info->licenses);
	dynarray_free(pkg_info->replaces);
	dynarray_free(pkg_info->depends);
	dynarray_free(pkg_info->conflicts);
	dynarray_free(pkg_info->provides);
	dynarray_free(pkg_info->optdepends);
	dynarray_free(pkg_info->makedepends);
	dynarray_free(pkg_info->checkdepends);

	free(pkg_info);
}

/**
 * Advance the pointer until all spaces are skipped.
 */
static inline char *trim_spaces_front(char *ptr) {
	while (ptr[0] == ' ') {
		ptr++;
	}

	return ptr;
}

/**
 * Given a string pointer in the middle of a string, move over all spaces in the
 * given direction. The final space is replaced with a NULL-byte.
 */
static inline void trim_spaces_back(char *ptr) {
	if (ptr[0] != ' ') {
		return;
	}

	while (ptr[-1] == ' ') {
		ptr--;
	}

	ptr[0] = '\0';
}

#define PKG_INFO_STRING(key, field) if (strcmp(key_ptr, key) == 0) { pkg_info->field = strdup(value_ptr); goto advance; }
#define PKG_INFO_INT(key, field) if (strcmp(key_ptr, key) == 0) { pkg_info->field = atoi(value_ptr); goto advance; }
#define PKG_INFO_ARRAY(key, field) if (strcmp(key_ptr, key) == 0) { \
	if (pkg_info->field == NULL) { pkg_info->field = dynarray_init(4); } \
	dynarray_add(pkg_info->field, value_ptr); goto advance; \
}

int package_info_parse(PkgInfo *pkg_info, char *pkg_info_str) {
	char *offset_ptr, *equals_ptr, *key_ptr, *value_ptr;

	bool end = false;

	// Iterate over all lines in file
	while (!end) {
		// This pointer will always point to the final character of the
		// current line, be it the position of a newline or the NULL byte at
		// the end of the entire string
		offset_ptr = strchr(pkg_info_str, '\n');

		// We replace the newline with a NULL byte. Now we know the line runs
		// until the next NULL byte.
		if (offset_ptr != NULL) {
			offset_ptr[0] = '\0';
		} else {
			// Advance pointer to the NULL byte of the string
			offset_ptr = pkg_info_str + 1;

			while (*offset_ptr != '\0') {
				offset_ptr++;
			}

			end = true;
		}

		// Skip comment lines
		if (pkg_info_str[0] == '#') {
			goto advance;
		}

		equals_ptr = strchr(pkg_info_str, '=');

		// If a line doesn't contain an equals sign, the file is invalid
		if (equals_ptr == NULL) {
			return 1;
		}

		// Trim whitespace from key
		key_ptr = trim_spaces_front(pkg_info_str);
		trim_spaces_back(equals_ptr - 1);

		// Trim spaces from value
		value_ptr = trim_spaces_front(equals_ptr + 1);
		trim_spaces_back(offset_ptr - 1);

		// Match key
		PKG_INFO_STRING("pkgname", name);
		PKG_INFO_STRING("pkgbase", base);
		PKG_INFO_STRING("pkgver", version);
		PKG_INFO_STRING("pkgdesc", description);
		PKG_INFO_INT("size", size);
		PKG_INFO_STRING("url", url);
		PKG_INFO_STRING("arch", arch);
		PKG_INFO_INT("builddate", build_date);
		PKG_INFO_STRING("packager", packager);
		PKG_INFO_STRING("pgpsig", pgpsig);
		PKG_INFO_INT("pgpsigsize", pgpsigsize);
		PKG_INFO_ARRAY("group", groups);
		PKG_INFO_ARRAY("license", licenses);
		PKG_INFO_ARRAY("replaces", replaces);
		PKG_INFO_ARRAY("depend", depends);
		PKG_INFO_ARRAY("optdepend", optdepends);
		PKG_INFO_ARRAY("makedepend", makedepends);
		PKG_INFO_ARRAY("checkdepend", checkdepends);

advance:
		pkg_info_str = offset_ptr + 1;
		continue;
	}

	return 0;
}