#include "pkg_db.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>

#define PKG_DB "../packages"
#define PKG_DB_LEN (sizeof(PKG_DB) - 1)
#define PKG_INFO_CMD "./get_pkg_attrs.sh"

bool load_package_info(package_info_t* info, char* pkgid) {
    memset(info, 0, sizeof(*info));

	// construct package description directory path and ensure it exists
    size_t pkgid_len = strlen(pkgid);
	size_t pkg_dir_len = PKG_DB_LEN + pkgid_len + 1;
	char* pkg_dir = malloc(pkg_dir_len + 1);
    if (!pkg_dir) {
        fprintf(stderr, "Failed to alloc pkg_dir\n");
        exit(1);
    }
    // pkg_dir = "PKG_DB/pkgid"
    memcpy(pkg_dir, PKG_DB, PKG_DB_LEN);
    pkg_dir[PKG_DB_LEN] = '/';
    memcpy(&pkg_dir[PKG_DB_LEN + 1], pkgid, pkgid_len + 1);

	if (access(pkg_dir, F_OK) != 0) {
        fprintf(stderr, "Package '%s' not found\n", pkgid);
        free(pkg_dir);
        return false;
    }

	// construct package description script path and ensure it exists
	size_t script_path_len = pkg_dir_len + pkgid_len + 4;
	info->script_path = malloc(script_path_len + 1);
    if (!info->script_path) {
        fprintf(stderr, "Failed to alloc info->script_path\n");
        exit(1);
    }

    memcpy(info->script_path, pkg_dir, pkg_dir_len);
    info->script_path[pkg_dir_len] = '/';
    memcpy(&info->script_path[pkg_dir_len + 1], pkgid, pkgid_len);
    memcpy(&info->script_path[script_path_len - 3], ".sh", 4);
	free(pkg_dir);
	if (access(info->script_path, F_OK) != 0) {
        fprintf(stderr, "Package '%s' broken, doesn't have description script\n", pkgid);
		free(info->script_path);
		return false;
    }

    int pipefds[2] = {0};
    if (pipe(pipefds) < 0) {
        fprintf(stderr, "Failed to create pipe\n");
        exit(1);
    }
    pid_t pid = fork();
    if (pid < 0) {
        fprintf(stderr, "Failed to create child process\n");
        exit(1);
    }

    if (pid == 0) {
        close(pipefds[0]);
        dup2(pipefds[1], STDOUT_FILENO);
        close(pipefds[1]);

        char* argv[] = { PKG_INFO_CMD, info->script_path, NULL };
        char* envp[] = { NULL };
        execve(PKG_INFO_CMD, argv, envp);
        fprintf(stderr, "execve failed\n");
        exit(127);
    }

    int wstatus;
    if (waitpid(pid, &wstatus, 0) < 0) {
        fprintf(stderr, "waitpid failed\n");
        exit(1);
    }
    if (WEXITSTATUS(wstatus) == 127) {
        exit(1);
    }

    ssize_t bytes_read = read(pipefds[0], info->package_attrs, sizeof(info->package_attrs));
    if (bytes_read < 0) {
        fprintf(stderr, "Failed to read from pipe\n");
        exit(1);
    }

    free(info->script_path);

    for (int i = 0; i < bytes_read;) {
        char atype = info->package_attrs[i];
        i++;
        switch (atype) {
        case 'i':
            info->attrs.id = &info->package_attrs[i];
            break;
        case 'n':
            info->attrs.name = &info->package_attrs[i];
            break;
        case 'd':
            info->attrs.desc = &info->package_attrs[i];
            break;
        }
        for(;info->package_attrs[i] && i < bytes_read; i++);
        i++;
    }

	return true;
}