/*
 * carmel-build
 * Copyright (c) 2024 Jeremy Baxter.
 */

#define _DEFAULT_SOURCE

#include <sys/stat.h>
#include <sys/wait.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <iniparser.h>

#include "util.h"

typedef struct {
	char *name;
	char *description;
	char *version;
	char *builder;
} manifest;

static const char *buildBase = "/tmp/carmel-";
static const char *defaultOutputFile = "auto";
static const char *defaultPackageName = "void";
static const char *defaultPackageVersion = "0";
static const char *defaultPackageBuilder = "builder.sh";
static bool oflag, vflag;

#define WARNV(...) if (vflag) warnx(__VA_ARGS__)

void
builder(const char *script)
{
	FILE *proc;
	ssize_t ret;
	int fd;
	char ch[1];

	proc = popen("sh", "w");
	fd = open(script, O_RDONLY);

	if (!proc)
		err(1, "cannot execute shell");
	if (fd == -1)
		err(1, "cannot open %s", script);
	
	while ((ret = read(fd, &ch, 1)) > 0) {
		fwrite(ch, sizeof(char), 1, proc);
	}

	if (ret == -1)
		err(1, "cannot read from %s", script);

	pclose(proc);
}

#define KEY(name, def) strdup(iniparser_getstring(ini, (":" name), (def)))

manifest
makeManifest(const char *path)
{
	dictionary *ini;
	manifest m;

	ini = iniparser_load(path);
	m.name = KEY("name", defaultPackageName);
	m.description = KEY("description", "");
	m.version = KEY("version", defaultPackageVersion);
	m.builder = KEY("builder", defaultPackageBuilder);
	iniparser_freedict(ini);

	return m;
}

#undef KEY

void
freeManifest(manifest *m)
{
	free(m->name);
	free(m->description);
	free(m->version);
	free(m->builder);
}

void
makeDirectory(const char *path)
{
	if (mkdir(path, 0710) == -1)
		err(1, "cannot create directory '%s'", path);
}

void
sh(const char *command)
{
	int ret;

	ret = system(command);
	if (ret == -1)
		err(1, "system");
	if (WEXITSTATUS(ret) != 0)
		errx(1, "command failed with exit code %d: %s", ret, command);
}

char *
workingDirectory(void)
{
	char *buffer;
	size_t len;

	len = 64;
	do {
		buffer = malloc(len * sizeof(char));
		len *= 2;
	} while (getcwd(buffer, len) == NULL);

	return buffer;
}

void
writeTo(const char *path, const char *contents)
{
	int fd, i;

	fd = open(path, O_WRONLY | O_CREAT, 0644);
	for (i = 0; contents[i] != 0; i++)
		write(fd, (char[]){contents[i]}, 1);
}

int
main(int argc, char **argv)
{
	manifest m;
	char *buildDirectory;
	char *outputFile;
	char *startDirectory;
	size_t buildDirectoryLen, outputFileLen;
	char ch;

	outputFileLen = strlen(defaultOutputFile) + 1;
	outputFile = malloc(outputFileLen * sizeof(char));
	strbcpy(outputFile, defaultOutputFile, outputFileLen);

	while ((ch = getopt(argc, argv, "C:o:v")) != -1) {
		switch (ch) {
		case 'C':
			changeDirectory(optarg);
			break;
		case 'o':
			oflag = 1;
			outputFileLen = strlen(optarg) + 1;
			outputFile = malloc(outputFileLen * sizeof(char));
			strbcpy(outputFile, optarg, outputFileLen);
			break;
		case 'v':
			vflag = 1;
			break;
		}
	}

	if (argc - optind != 1) {
		fputs("usage: carmel-build [-v] [-C directory] [-o output] manifest\n", stderr);
		return 1;
	}

	startDirectory = workingDirectory();

	if (!exists(argv[optind]))
		errx(1, "cannot open %s", argv[optind]);
	m = makeManifest(argv[optind]);

	if (strcmp(m.name, defaultPackageName) == 0)
		warnx("manifest name not provided; using '%s'", m.name);
	if (strcmp(m.version, defaultPackageVersion) == 0)
		warnx("manifest version not provided; using '%s'", m.version);
	if (strlen(m.builder) == 0)
		errx(1, "manifest builder not provided; using '%s'", m.builder);

	if (strcmp(outputFile, defaultOutputFile) == 0) {
		char *extension = ".tar.gz";
		outputFileLen = strlen(m.name) + 1 + strlen(m.version)
						+ strlen(extension) + 1;
		outputFile = malloc(outputFileLen * sizeof(char));
		snprintf(outputFile, outputFileLen, "%s-%s%s",
				 m.name, m.version, extension);
	}
	WARNV("building %s", outputFile);

	/* PIDs up to 7 digits */
	buildDirectoryLen = strlen(buildBase) + 8;
	buildDirectory = malloc(buildDirectoryLen * sizeof(char));
	snprintf(buildDirectory, buildDirectoryLen, "%s%d",
			 buildBase, getpid());

	WARNV("entering build origin");
	makeDirectory(buildDirectory);
	changeDirectory(buildDirectory);
	makeDirectory("origin");
	changeDirectory("origin");

	{
		char *buffer;
		size_t len;

		len = strlen(startDirectory) + 1 + strlen(m.builder) + 1;
		buffer = malloc(len * sizeof(char));
		snprintf(buffer, len, "%s/%s", startDirectory, m.builder);
		copyFile(buffer, "builder.sh");
	}

	WARNV("executing builder");
	setenv("out", buildDirectory, 1);
	builder("builder.sh");

	changeDirectory("..");
	sh("rm -fr origin/");

	WARNV("writing to carmel-meta");
	makeDirectory("carmel-meta");
	changeDirectory("carmel-meta");
	writeTo("name", m.name);
	writeTo("description", m.description);
	writeTo("version", m.version);

	WARNV("making tarball");
	setenv("out", outputFile, 1);
	setenv("start", startDirectory, 1);
	setenv("build", buildDirectory, 1);
	changeDirectory(buildDirectory);
	sh("tar -czf \"$out\" *");
	sh("mv \"$out\" \"$start\"/");
	changeDirectory(startDirectory);
	sh("rm -fr \"$build\"");

	freeManifest(&m);
	free(outputFile);
	free(startDirectory);

	return 0;
}