/*
 * Copyright 2013 (c) Anna Schumaker.
 */
#include <core/file.h>
#include <core/string.h>
#include <core/version.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>

#define REPORT_ERROR(fname, error) \
	g_printerr("%s (%s:%d): %s: %s\n", __func__, __FILE__, __LINE__, fname, error)
#define REPORT_ERRNO(fname) REPORT_ERROR(fname, strerror(errno))

static gchar *__file_path(const gchar *base, const gchar *dir,
			  const gchar *name)
{
	return g_build_filename(base, OCARINA_NAME, dir ? dir : "", name, NULL);
}

static gchar *__file_build_path(const gchar *base, const gchar *dir,
				const gchar *name)
{
	if (string_length(name) == 0)
		return g_strdup("");
	return __file_path(base, dir, name);
}

static gchar *__file_build_tmp(const gchar *base, const gchar *dir,
			       const gchar *name)
{
	gchar *tmp, *res;

	if (string_length(name) == 0)
		return g_strdup("");

	tmp = g_strdup_printf(".%s.tmp", name);
	res = __file_path(base, dir, tmp);
	g_free(tmp);

	return res;
}

static bool __file_exists(gchar *path)
{
	bool ret = g_file_test(path, G_FILE_TEST_EXISTS);
	g_free(path);
	return ret;
}

static FILE *__file_open(gchar *path, const gchar *mode)
{
	FILE *ret = g_fopen(path, mode);

	if (!ret)
		REPORT_ERRNO(path);
	g_free(path);
	return ret;
}

static void __file_close(FILE *file, gchar *path, gchar *tmp)
{
	if (file) {
		fclose(file);
		if (path && tmp)
			g_rename(tmp, path);
	}

	g_free(path);
	g_free(tmp);
}

static bool __file_mkdir(const gchar *basedir, const gchar *subdir)
{
	gchar *dir = __file_path(basedir, subdir, NULL);
	int    ret = g_mkdir_with_parents(dir, 0755);

	if (ret != 0)
		REPORT_ERRNO(dir);
	g_free(dir);
	return ret == 0;
}

static bool __file_can_write(struct file *file)
{
	gchar *path = file_path(file);
	bool   ret  = true;

	if (g_access(path, F_OK) == 0 && g_access(path, W_OK) < 0)
		ret = false;

	g_free(path);
	return ret;
}


void file_init(struct file *file,    const gchar *name,
	       unsigned int version, unsigned int min)
{
	file->f_mode = OPEN_READ;
	file->f_version = version;
	file->f_prev = 0;
	file->f_min  = 0;
	file->f_file = NULL;
	file->f_name = name;
}

void cache_file_init(struct cache_file *file, gchar *subdir, gchar *name)
{
	file->cf_file   = NULL;
	file->cf_name   = name;
	file->cf_subdir = subdir;
}

gchar *file_path(struct file *file)
{
	return __file_build_path(g_get_user_data_dir(), NULL, file->f_name);
}

gchar *cache_file_path(struct cache_file *file)
{
	return __file_build_path(g_get_user_cache_dir(), file->cf_subdir,
				 file->cf_name);
}

gchar *file_write_path(struct file *file)
{
	return __file_build_tmp(g_get_user_data_dir(), NULL, file->f_name);
}

gchar *cache_file_write_path(struct cache_file *file)
{
	return __file_build_tmp(g_get_user_cache_dir(), file->cf_subdir,
				file->cf_name);
}

const unsigned int file_version(struct file *file)
{
	if (file->f_file && (file->f_mode == OPEN_READ))
		return file->f_prev;
	return file->f_version;
}

bool file_exists(struct file *file)
{
	return __file_exists(file_path(file));
}

bool cache_file_exists(struct cache_file *file)
{
	return __file_exists(cache_file_path(file));
}

static bool __file_open_read(struct file *file)
{
	if (!file_exists(file))
		return false;

	file->f_file = __file_open(file_path(file), "r");
	if (!file->f_file)
		return false;

	file->f_mode = OPEN_READ;
	if (file_readf(file, "%u\n", &file->f_prev) != 1)
		return false;
	if (file->f_prev < file->f_min) {
		REPORT_ERROR(file->f_name, "File too old to be upgraded.");
		file_close(file);
		exit(1);
	}
	if (file->f_prev > file->f_version) {
		REPORT_ERROR(file->f_name, "File too new to be opened.");
		file_close(file);
		exit(1);
	}
	return true;
}

static bool __file_open_write(struct file *file)
{
	if (!__file_mkdir(g_get_user_data_dir(), NULL))
		return false;
	if (!__file_can_write(file))
		return false;

	file->f_file = __file_open(file_write_path(file), "w");
	if (!file->f_file)
		return false;

	file->f_mode = OPEN_WRITE;
	return file_writef(file, "%d\n", file->f_version) > 0;
}

bool file_open(struct file *file, enum open_mode mode)
{
	if ((string_length(file->f_name) == 0) || (file->f_file != NULL))
		return false;

	if (mode == OPEN_READ)
		return __file_open_read(file);
	return __file_open_write(file);
}

bool cache_file_open(struct cache_file *file, enum open_mode mode)
{
	if (mode == OPEN_READ)
		return false;
	if ((string_length(file->cf_name) == 0) || (file->cf_file != NULL))
		return false;
	if (!__file_mkdir(g_get_user_cache_dir(), file->cf_subdir))
		return false;

	file->cf_file = __file_open(cache_file_write_path(file), "wb");
	return file->cf_file != NULL;
}

void file_close(struct file *file)
{
	__file_close(file->f_file,
		     file->f_mode == OPEN_WRITE ? file_path(file) : NULL,
		     file->f_mode == OPEN_WRITE ? file_write_path(file) : NULL);
	file->f_file = NULL;
}

void cache_file_close(struct cache_file *file)
{
	__file_close(file->cf_file,
		     cache_file_path(file),
		     cache_file_write_path(file));
	file->cf_file = NULL;
}

int file_readf(struct file *file, const char *fmt, ...)
{
	va_list argp;
	int ret;

	va_start(argp, fmt);
	ret = vfscanf(file->f_file, fmt, argp);
	va_end(argp);

	return ret;
}

gchar *file_readl(struct file *file)
{
	gchar *res;

	if (file_readf(file, "%m[^\n]\n", &res) == 0)
		return g_strdup("");

	g_strstrip(res);
	return res;
}

int file_writef(struct file *file, const char *fmt, ...)
{
	va_list argp;
	int ret;

	va_start(argp, fmt);
	ret = g_vfprintf(file->f_file, fmt, argp);
	va_end(argp);

	if (ret < 0)
		REPORT_ERRNO(file->f_name);
	return ret;
}

int cache_file_write(struct cache_file *file, const void *data, size_t len)
{
	if (fwrite(data, len, 1, file->cf_file) == 1)
		return len;
	return -1;
}

bool cache_file_import(struct cache_file *file, const gchar *srcpath)
{
	gchar *contents = NULL;
	gsize  length   = 0;

	if (!file->cf_file || !srcpath)
		return false;
	if (!g_file_get_contents(srcpath, &contents, &length, NULL))
		return false;

	cache_file_write(file, contents, length);
	return true;
}

bool file_remove(struct file *file)
{
	int ret = -1;
	gchar *path;

	if (!file->f_file) {
		path = file_path(file);
		ret  = g_unlink(path);
		g_free(path);
	}

	return ret == 0;
}