/*
 * 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 void __file_init_common(struct file *file, const gchar *subdir,
			       const gchar *name, unsigned int min,
			       const gchar *(*user_dir)(void))
{
	file->f_file     = NULL;
	file->f_name     = name;
	file->f_subdir   = subdir;
	file->f_mode     = CLOSED;
	file->f_version  = OCARINA_MINOR_VERSION;
	file->f_prev     = 0;
	file->f_min      = min;
	file->f_user_dir = user_dir;
}

static bool __file_open(struct file *file, enum open_mode mode)
{
	gchar *cmode, *path;

	if (mode == OPEN_READ || mode == OPEN_READ_BINARY) {
		cmode = "r";
		path = file_path(file);
	} else {
		cmode = "w";
		path = file_write_path(file);
	}

	file->f_file = g_fopen(path, cmode);
	if (!file->f_file)
		REPORT_ERRNO(path);
	g_free(path);
	return file->f_file != NULL;
}

static bool __file_mkdir(struct file *file)
{
	gchar *dir = g_build_filename(file->f_user_dir(), OCARINA_NAME,
				      file->f_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_data(struct file *file, const gchar *subdir,
		    const gchar *name, unsigned int min)
{
	__file_init_common(file, subdir, name, min, g_get_user_data_dir);
}

void file_init_cache(struct file *file, const gchar *subdir, const gchar *name)
{
	__file_init_common(file, subdir, name, 0, g_get_user_cache_dir);
}

gchar *file_path(struct file *file)
{
	if (string_length(file->f_name) == 0)
		return g_strdup("");
	return g_build_filename(file->f_user_dir(), OCARINA_NAME,
				file->f_subdir, file->f_name, NULL);
}

gchar *file_write_path(struct file *file)
{
	gchar *tmp, *res;

	if (string_length(file->f_name) == 0)
		return g_strdup("");

	tmp = g_strdup_printf(".%s.tmp", file->f_name);
	res = g_build_filename(file->f_user_dir(), OCARINA_NAME,
			       file->f_subdir, tmp, NULL);
	g_free(tmp);

	return res;
}

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

static bool __file_open_read(struct file *file, enum open_mode mode)
{
	if (!file_exists(file))
		return false;
	if (!__file_open(file, mode))
		return false;

	file->f_mode = mode;
	if (mode == OPEN_READ_BINARY)
		return true;

	file->f_prev = file_readu(file);
	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, enum open_mode mode)
{
	if (!__file_mkdir(file))
		return false;
	if (!__file_can_write(file))
		return false;
	if (!__file_open(file, OPEN_WRITE))
		return false;

	file->f_mode = mode;
	if (mode == OPEN_WRITE_BINARY)
		return true;
	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 == CLOSED)
		return false;

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

void file_close(struct file *file)
{
	gchar *path = file_path(file);
	gchar *tmp  = file_write_path(file);

	if (file->f_file) {
		fclose(file->f_file);
		if (file->f_mode == OPEN_WRITE || file->f_mode == OPEN_WRITE_BINARY)
			g_rename(tmp, path);
	}

	file->f_file = NULL;
	file->f_mode = CLOSED;

	g_free(path);
	g_free(tmp);
}

gchar *file_readw(struct file *file)
{
	gchar *s;
	return fscanf(file->f_file, "%ms%*c", &s) ? s : g_strdup("");
}

gchar *file_readl(struct file *file)
{
	gchar *s   = NULL;
	size_t len = 0;
	return getline(&s, &len, file->f_file) ? g_strchomp(s) : g_strdup("");
}

unsigned int file_readu(struct file *file)
{
	unsigned int u;
	return fscanf(file->f_file, "%u%*c", &u) ? u : 0;
}

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;
}

gchar *file_read(struct file *file)
{
	int fd = fileno(file->f_file);
	struct stat st;
	gchar *buf;

	if (fstat(fd, &st) < 0)
		return NULL;

	buf = g_malloc0(st.st_size + 1);
	if (fread(buf, st.st_size, 1, file->f_file) == 1)
		return buf;

	g_free(buf);
	return NULL;
}

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

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

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

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

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

	if (!file->f_file) {
		path = file_path(file);
		ret  = g_unlink(path);
		dir  = g_path_get_dirname(path);
		if (string_length(file->f_subdir) > 0)
			g_rmdir(dir);
		g_free(path);
		g_free(dir);
	}

	return ret == 0;
}