/*
 * The MIT License
 *
 * Copyright (c) 2014 GitHub, Inc
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "rugged.h"

const char *RUGGED_ERROR_NAMES[] = {
	"None",            /* GITERR_NONE */
	"NoMemError",      /* GITERR_NOMEMORY, */
	"OSError",         /* GITERR_OS, */
	"InvalidError",    /* GITERR_INVALID, */
	"ReferenceError",  /* GITERR_REFERENCE, */
	"ZlibError",       /* GITERR_ZLIB, */
	"RepositoryError", /* GITERR_REPOSITORY, */
	"ConfigError",     /* GITERR_CONFIG, */
	"RegexError",      /* GITERR_REGEX, */
	"OdbError",        /* GITERR_ODB, */
	"IndexError",      /* GITERR_INDEX, */
	"ObjectError",     /* GITERR_OBJECT, */
	"NetworkError",    /* GITERR_NET, */
	"TagError",        /* GITERR_TAG, */
	"TreeError",       /* GITERR_TREE, */
	"IndexerError",    /* GITERR_INDEXER, */
	"SslError",        /* GITERR_SSL, */
	"SubmoduleError",  /* GITERR_SUBMODULE, */
	"ThreadError",     /* GITERR_THREAD, */
	"StashError",      /* GITERR_STASH, */
	"CheckoutError",   /* GITERR_CHECKOUT, */
	"FetchheadError",  /* GITERR_FETCHHEAD, */
	"MergeError",      /* GITERR_MERGE, */
	"SshError",        /* GITERR_SSH, */
	"FilterError"      /* GITERR_FILTER, */
};

#define RUGGED_ERROR_COUNT (int)((sizeof(RUGGED_ERROR_NAMES)/sizeof(RUGGED_ERROR_NAMES[0])))

VALUE rb_mRugged;
VALUE rb_eRuggedError;
VALUE rb_eRuggedErrors[RUGGED_ERROR_COUNT];

static VALUE rb_mShutdownHook;

/*
 *  call-seq:
 *     Rugged.libgit2_version -> version
 *
 *  Returns an array representing the current libgit2 version in use. Using
 *  the array makes it easier for the end-user to take conditional actions
 *  based on each respective version attribute: major, minor, rev.
 *
 *    Rugged.libgit2_version #=> [0, 17, 0]
 */
static VALUE rb_git_libgit2_version(VALUE self)
{
	int major;
	int minor;
	int rev;

	git_libgit2_version(&major, &minor, &rev);

	// We return an array of three elements to represent the version components
	return rb_ary_new3(3, INT2NUM(major), INT2NUM(minor), INT2NUM(rev));
}

/*
 *  call-seq:
 *     Rugged.features -> [feature, ...]
 *
 *  Returns an array representing the features that libgit2 was compiled
 *  with — this includes `:threads` (thread support), `:https` and `:ssh`.
 *
 *    Rugged.features #=> [:threads, :https]
 */
static VALUE rb_git_features(VALUE self)
{
	VALUE ret_arr = rb_ary_new();

	int caps = git_libgit2_features();

	if (caps & GIT_FEATURE_THREADS)
		rb_ary_push(ret_arr, CSTR2SYM("threads"));

	if (caps & GIT_FEATURE_HTTPS)
		rb_ary_push(ret_arr, CSTR2SYM("https"));

	if (caps & GIT_FEATURE_SSH)
		rb_ary_push(ret_arr, CSTR2SYM("ssh"));

	return ret_arr;
}

/*
 *  call-seq:
 *    Rugged.hex_to_raw(oid) -> raw_buffer
 *
 *  Turn a string of 40 hexadecimal characters into the buffer of
 *  20 bytes it represents.
 *
 *    Rugged.hex_to_raw('d8786bfc97485e8d7b19b21fb88c8ef1f199fc3f')
 *    #=> "\330xk\374\227H^\215{\031\262\037\270\214\216\361\361\231\374?"
 */
static VALUE rb_git_hex_to_raw(VALUE self, VALUE hex)
{
	git_oid oid;

	Check_Type(hex, T_STRING);
	rugged_exception_check(git_oid_fromstr(&oid, StringValueCStr(hex)));

	return rb_str_new((const char *)oid.id, 20);
}

/*
 *  call-seq:
 *    Rugged.raw_to_hex(buffer) -> hex_oid
 *
 *  Turn a buffer of 20 bytes (representing a SHA1 OID) into its
 *  readable hexadecimal representation.
 *
 *    Rugged.raw_to_hex("\330xk\374\227H^\215{\031\262\037\270\214\216\361\361\231\374?")
 *    #=> "d8786bfc97485e8d7b19b21fb88c8ef1f199fc3f"
 */
static VALUE rb_git_raw_to_hex(VALUE self, VALUE raw)
{
	git_oid oid;
	char out[40];

	Check_Type(raw, T_STRING);

	if (RSTRING_LEN(raw) != GIT_OID_RAWSZ)
		rb_raise(rb_eTypeError, "Invalid buffer size for an OID");

	git_oid_fromraw(&oid, (const unsigned char *)RSTRING_PTR(raw));
	git_oid_fmt(out, &oid);

	return rb_str_new(out, 40);
}

/*
 *  call-seq:
 *    Rugged.prettify_message(message, strip_comments = '#') -> clean_message
 *
 *  Process a commit or tag message into standard form, by stripping trailing spaces and
 *  comments, and making sure that the message has a proper header line.
 */
static VALUE rb_git_prettify_message(int argc, VALUE *argv, VALUE self)
{
	char comment_char = '#';
	int strip_comments = 1;

	git_buf message = { NULL };
	VALUE rb_message, rb_strip;
	int error;
	VALUE result = Qnil;

	rb_scan_args(argc, argv, "11", &rb_message, &rb_strip);

	Check_Type(rb_message, T_STRING);
	
	switch (TYPE(rb_strip)) {
	case T_FALSE:
		strip_comments = 0;
		break;

	case T_STRING:
		if (RSTRING_LEN(rb_strip) > 0)
			comment_char = RSTRING_PTR(rb_strip)[0];
		break;

	case T_TRUE:
	case T_NIL:
	default:
		break;
	}

	error = git_message_prettify(&message,
				StringValueCStr(rb_message), strip_comments, comment_char);

	if (!error)
		result = rb_enc_str_new(message.ptr, message.size, rb_utf8_encoding());

	git_buf_free(&message);
	rugged_exception_check(error);

	return result;
}

static VALUE minimize_cb(VALUE rb_oid, git_oid_shorten *shortener)
{
	Check_Type(rb_oid, T_STRING);
	git_oid_shorten_add(shortener, RSTRING_PTR(rb_oid));
	return Qnil;
}

static VALUE minimize_yield(VALUE rb_oid, VALUE *data)
{
	rb_funcall(data[0], rb_intern("call"), 1,
		rb_str_substr(rb_oid, 0, FIX2INT(data[1])));
	return Qnil;
}

/*
 *  call-seq:
 *    Rugged.minimize_oid(oid_iterator, min_length = 7) { |short_oid| block }
 *    Rugged.minimize_oid(oid_iterator, min_length = 7) -> min_length
 *
 *  Iterate through +oid_iterator+, which should yield any number of SHA1 OIDs
 *  (represented as 40-character hexadecimal strings), and tries to minify them.
 *
 *  Minifying a set of a SHA1 strings means finding the shortest root substring
 *  for each string that uniquely identifies it.
 *
 *  If no +block+ is given, the function will return the minimal length as an
 *  integer value:
 *
 *    oids = [
 *      'd8786bfc974aaaaaaaaaaaaaaaaaaaaaaaaaaaaa',
 *      'd8786bfc974bbbbbbbbbbbbbbbbbbbbbbbbbbbbb',
 *      'd8786bfc974ccccccccccccccccccccccccccccc',
 *      '68d041ee999cb07c6496fbdd4f384095de6ca9e1',
 *    ]
 *
 *    Rugged.minimize_oids(oids) #=> 12
 *
 *  If a +block+ is given, it will be called with each OID from +iterator+
 *  in its minified form:
 *
 *    Rugged.minimize_oid(oids) { |oid| puts oid }
 *
 *  produces:
 *
 *    d8786bfc974a
 *    d8786bfc974b
 *    d8786bfc974c
 *    68d041ee999c
 *
 *  The optional +min_length+ argument allows you to specify a lower bound for
 *  the minified strings; returned strings won't be shorter than the given value,
 *  even if they would still be uniquely represented.
 *
 *    Rugged.minimize_oid(oids, 18) #=> 18
 */
static VALUE rb_git_minimize_oid(int argc, VALUE *argv, VALUE self)
{
	git_oid_shorten *shrt;
	int length, minlen = 7;
	VALUE rb_enum, rb_minlen, rb_block;

	rb_scan_args(argc, argv, "11&", &rb_enum, &rb_minlen, &rb_block);

	if (!NIL_P(rb_minlen)) {
		Check_Type(rb_minlen, T_FIXNUM);
		minlen = FIX2INT(rb_minlen);
	}

	if (!rb_respond_to(rb_enum, rb_intern("each")))
		rb_raise(rb_eTypeError, "Expecting an Enumerable instance");

	shrt = git_oid_shorten_new(minlen);

	rb_iterate(rb_each, rb_enum, &minimize_cb, (VALUE)shrt);
	length = git_oid_shorten_add(shrt, NULL);

	git_oid_shorten_free(shrt);
	rugged_exception_check(length);

	if (!NIL_P(rb_block)) {
		VALUE yield_data[2];

		yield_data[0] = rb_block;
		yield_data[1] = INT2FIX(length);

		rb_iterate(rb_each, rb_enum, &minimize_yield, (VALUE)yield_data);
		return Qnil;
	}

	return INT2FIX(length);
}

static void cleanup_cb(void *unused)
{
	(void)unused;
	git_threads_shutdown();
}

void rugged_exception_raise(void)
{
	VALUE err_klass, err_obj;
	const git_error *error;
	const char *err_message;

	error = giterr_last();

	if (error && error->klass >= 0 && error->klass < RUGGED_ERROR_COUNT) {
		err_klass = rb_eRuggedErrors[error->klass];
		err_message = error->message;
	} else {
		err_klass = rb_eRuggedErrors[2]; /* InvalidError */
		err_message = "Unknown Error";
	}

	err_obj = rb_exc_new2(err_klass, err_message);
	giterr_clear();
	rb_exc_raise(err_obj);
}

VALUE rugged__block_yield_splat(VALUE args) {
	VALUE block = rb_ary_shift(args);
	int n = RARRAY_LENINT(args);

	if (n == 0) {
		return rb_funcall(block, rb_intern("call"), 0);
	} else {
		int i;
		VALUE *argv;
		argv = ALLOCA_N(VALUE, n);

		for (i=0; i < n; i++) {
			argv[i] = rb_ary_entry(args, i);
		}

		return rb_funcall2(block, rb_intern("call"), n, argv);
	}
}

/*
 *  call-seq:
 *    Rugged.__cache_usage__ -> [current, max]
 *
 *  Returns an array representing the current bytes in the internal
 *  libgit2 cache and the maximum size of the cache.
 */
static VALUE rb_git_cache_usage(VALUE self)
{
	int64_t used, max;
	git_libgit2_opts(GIT_OPT_GET_CACHED_MEMORY, &used, &max);
	return rb_ary_new3(2, LL2NUM(used), LL2NUM(max));
}

VALUE rugged_strarray_to_rb_ary(git_strarray *str_array)
{
	VALUE rb_array = rb_ary_new2(str_array->count);
	size_t i;

	for (i = 0; i < str_array->count; ++i) {
		rb_ary_push(rb_array, rb_str_new_utf8(str_array->strings[i]));
	}

	return rb_array;
}

void rugged_rb_ary_to_strarray(VALUE rb_array, git_strarray *str_array)
{
	int i;

	str_array->strings = NULL;
	str_array->count = 0;

	if (NIL_P(rb_array))
		return;

	if (TYPE(rb_array) == T_STRING) {
		str_array->count = 1;
		str_array->strings = xmalloc(sizeof(char *));
		str_array->strings[0] = StringValueCStr(rb_array);
		return;
	}

	Check_Type(rb_array, T_ARRAY);

	for (i = 0; i < RARRAY_LEN(rb_array); ++i)
		Check_Type(rb_ary_entry(rb_array, i), T_STRING);

	str_array->count = RARRAY_LEN(rb_array);
	str_array->strings = xmalloc(str_array->count * sizeof(char *));

	for (i = 0; i < RARRAY_LEN(rb_array); ++i) {
		VALUE rb_string = rb_ary_entry(rb_array, i);
		str_array->strings[i] = StringValueCStr(rb_string);
	}
}

void Init_rugged(void)
{
	rb_mRugged = rb_define_module("Rugged");

	/* Initialize the Error classes */
	{
		int i;

		rb_eRuggedError = rb_define_class_under(rb_mRugged, "Error", rb_eStandardError);

		rb_eRuggedErrors[0] = rb_define_class_under(rb_mRugged, RUGGED_ERROR_NAMES[0], rb_eNoMemError);
		rb_eRuggedErrors[1] = rb_define_class_under(rb_mRugged, RUGGED_ERROR_NAMES[1], rb_eIOError);
		rb_eRuggedErrors[2] = rb_define_class_under(rb_mRugged, RUGGED_ERROR_NAMES[2], rb_eArgError);

		for (i = 3; i < RUGGED_ERROR_COUNT; ++i) {
			rb_eRuggedErrors[i] = rb_define_class_under(rb_mRugged, RUGGED_ERROR_NAMES[i], rb_eRuggedError);
		}
	}

	rb_define_module_function(rb_mRugged, "libgit2_version", rb_git_libgit2_version, 0);
	rb_define_module_function(rb_mRugged, "features", rb_git_features, 0);
	rb_define_module_function(rb_mRugged, "hex_to_raw", rb_git_hex_to_raw, 1);
	rb_define_module_function(rb_mRugged, "raw_to_hex", rb_git_raw_to_hex, 1);
	rb_define_module_function(rb_mRugged, "minimize_oid", rb_git_minimize_oid, -1);
	rb_define_module_function(rb_mRugged, "prettify_message", rb_git_prettify_message, -1);
	rb_define_module_function(rb_mRugged, "__cache_usage__", rb_git_cache_usage, 0);

	Init_rugged_reference();
	Init_rugged_reference_collection();

	Init_rugged_object();
	Init_rugged_commit();
	Init_rugged_tree();
	Init_rugged_tag();
	Init_rugged_tag_collection();
	Init_rugged_blob();

	Init_rugged_index();
	Init_rugged_repo();
	Init_rugged_revwalk();
	Init_rugged_branch();
	Init_rugged_branch_collection();
	Init_rugged_config();
	Init_rugged_remote();
	Init_rugged_remote_collection();
	Init_rugged_notes();
	Init_rugged_settings();
	Init_rugged_diff();
	Init_rugged_patch();
	Init_rugged_diff_delta();
	Init_rugged_diff_hunk();
	Init_rugged_diff_line();
	Init_rugged_blame();
	Init_rugged_cred();

	/*
	 * Sort the repository contents in no particular ordering;
	 * this sorting is arbitrary, implementation-specific
	 * and subject to change at any time.
	 * This is the default sorting for new walkers.
	 */
	rb_define_const(rb_mRugged, "SORT_NONE", INT2FIX(GIT_SORT_NONE));

	/*
	 * Sort the repository contents in topological order
	 * (parents before children); this sorting mode
	 * can be combined with time sorting.
	 */
	rb_define_const(rb_mRugged, "SORT_TOPO", INT2FIX(GIT_SORT_TOPOLOGICAL));

	/*
	 * Sort the repository contents by commit time;
	 * this sorting mode can be combined with
	 * topological sorting.
	 */
	rb_define_const(rb_mRugged, "SORT_DATE", INT2FIX(GIT_SORT_TIME));

	/*
	 * Iterate through the repository contents in reverse
	 * order; this sorting mode can be combined with
	 * any of the above.
	 */
	rb_define_const(rb_mRugged, "SORT_REVERSE", INT2FIX(GIT_SORT_REVERSE));

	/* Initialize libgit2 */
	git_threads_init();

	/* Hook a global object to cleanup the library
	 * on shutdown */
	rb_mShutdownHook = Data_Wrap_Struct(rb_cObject, NULL, &cleanup_cb, NULL);
	rb_global_variable(&rb_mShutdownHook);
}

