// Copyright (C) 2011 Red Hat, Inc. All rights reserved.
//
// This file is part of the thin-provisioning-tools source.
//
// thin-provisioning-tools is free software: you can redistribute it
// and/or modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation, either version 3 of
// the License, or (at your option) any later version.
//
// thin-provisioning-tools is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty
// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with thin-provisioning-tools.  If not, see
// <http://www.gnu.org/licenses/>.

#include <iostream>
#include <getopt.h>
#include <libgen.h>

#include "version.h"

#include "base/application.h"
#include "base/error_state.h"
#include "base/nested_output.h"
#include "persistent-data/data-structures/btree_counter.h"
#include "persistent-data/space-maps/core.h"
#include "persistent-data/space-maps/disk.h"
#include "persistent-data/file_utils.h"
#include "thin-provisioning/device_tree.h"
#include "thin-provisioning/mapping_tree.h"
#include "thin-provisioning/superblock.h"
#include "thin-provisioning/commands.h"

using namespace base;
using namespace std;
using namespace thin_provisioning;

//----------------------------------------------------------------

namespace {
	block_manager<>::ptr
	open_bm(string const &path) {
		block_address nr_blocks = get_nr_blocks(path);
		block_manager<>::mode m = block_manager<>::READ_ONLY;
		return block_manager<>::ptr(new block_manager<>(path, nr_blocks, 1, m));
	}

	transaction_manager::ptr
	open_tm(block_manager<>::ptr bm) {
		space_map::ptr sm(new core_map(bm->get_nr_blocks()));
		sm->inc(superblock_detail::SUPERBLOCK_LOCATION);
		transaction_manager::ptr tm(new transaction_manager(bm, sm));
		return tm;
	}

	//--------------------------------

	class superblock_reporter : public superblock_detail::damage_visitor {
	public:
		superblock_reporter(nested_output &out)
		: out_(out),
		  err_(NO_ERROR) {
		}

		virtual void visit(superblock_detail::superblock_corruption const &d) {
			out_ << "superblock is corrupt" << end_message();
			{
				nested_output::nest _ = out_.push();
				out_ << d.desc_ << end_message();
			}
			err_ << FATAL;
		}

		base::error_state get_error() const {
			return err_;
		}

	private:
		nested_output &out_;
		error_state err_;
	};

	//--------------------------------

	class devices_reporter : public device_tree_detail::damage_visitor {
	public:
		devices_reporter(nested_output &out)
		: out_(out),
		  err_(NO_ERROR) {
		}

		virtual void visit(device_tree_detail::missing_devices const &d) {
			out_ << "missing devices: " << d.keys_ << end_message();
			{
				nested_output::nest _ = out_.push();
				out_ << d.desc_ << end_message();
			}

			err_ << FATAL;
		}

		error_state get_error() const {
			return err_;
		}

	private:
		nested_output &out_;
		error_state err_;
	};

	//--------------------------------

	class mapping_reporter : public mapping_tree_detail::damage_visitor {
	public:
		mapping_reporter(nested_output &out)
		: out_(out),
		  err_(NO_ERROR) {
		}

		virtual void visit(mapping_tree_detail::missing_devices const &d) {
			out_ << "missing all mappings for devices: " << d.keys_ << end_message();
			{
				nested_output::nest _ = out_.push();
				out_ << d.desc_ << end_message();
			}
			err_ << FATAL;
		}

		virtual void visit(mapping_tree_detail::missing_mappings const &d) {
			out_ << "thin device " << d.thin_dev_ << " is missing mappings " << d.keys_ << end_message();
			{
				nested_output::nest _ = out_.push();
				out_ << d.desc_ << end_message();
			}
			err_ << FATAL;
		}

		error_state get_error() const {
			return err_;
		}

	private:
		nested_output &out_;
		error_state err_;
	};

	//--------------------------------

	struct flags {
		flags()
			: check_device_tree(true),
			  check_mapping_tree_level1(true),
			  check_mapping_tree_level2(true),
			  ignore_non_fatal_errors(false),
			  quiet(false),
			  clear_needs_check_flag_on_success(false) {
		}

		bool check_device_tree;
		bool check_mapping_tree_level1;
		bool check_mapping_tree_level2;

		bool ignore_non_fatal_errors;

		bool quiet;
		bool clear_needs_check_flag_on_success;
	};

	void count_trees(transaction_manager::ptr tm,
			 superblock_detail::superblock &sb,
			 block_counter &bc) {

		// Count the device tree
		{
			noop_value_counter<device_tree_detail::device_details> vc;
			device_tree dtree(*tm, sb.device_details_root_,
					  device_tree_detail::device_details_traits::ref_counter());
			count_btree_blocks(dtree, bc, vc);
		}

		// Count the mapping tree
		{
			noop_value_counter<mapping_tree_detail::block_time> vc;
			mapping_tree mtree(*tm, sb.data_mapping_root_,
					   mapping_tree_detail::block_traits::ref_counter(tm->get_sm()));
			count_btree_blocks(mtree, bc, vc);
		}
	}

	error_state check_space_map_counts(flags const &fs, nested_output &out,
					   superblock_detail::superblock &sb,
					   block_manager<>::ptr bm,
					   transaction_manager::ptr tm) {
		block_counter bc;

		// Count the superblock
		bc.inc(superblock_detail::SUPERBLOCK_LOCATION);
		count_trees(tm, sb, bc);

		// Count the metadata snap, if present
		if (sb.metadata_snap_ != superblock_detail::SUPERBLOCK_LOCATION) {
			bc.inc(sb.metadata_snap_);

			superblock_detail::superblock snap = read_superblock(bm, sb.metadata_snap_);
			count_trees(tm, snap, bc);
		}

		// Count the metadata space map
		{
			persistent_space_map::ptr metadata_sm =
				open_metadata_sm(*tm, static_cast<void *>(&sb.metadata_space_map_root_));
			metadata_sm->count_metadata(bc);
		}

		// Count the data space map
		{
			persistent_space_map::ptr data_sm =
				open_disk_sm(*tm, static_cast<void *>(&sb.data_space_map_root_));
			data_sm->count_metadata(bc);
		}

		// Finally we need to check the metadata space map agrees
		// with the counts we've just calculated.
		error_state err = NO_ERROR;
		nested_output::nest _ = out.push();
		persistent_space_map::ptr metadata_sm =
			open_metadata_sm(*tm, static_cast<void *>(&sb.metadata_space_map_root_));
		for (unsigned b = 0; b < metadata_sm->get_nr_blocks(); b++) {
			ref_t c_actual = metadata_sm->get_count(b);
			ref_t c_expected = bc.get_count(b);

			if (c_actual != c_expected) {
				out << "metadata reference counts differ for block " << b
				    << ", expected " << c_expected
				    << ", but got " << c_actual
				    << end_message();

				err << (c_actual > c_expected ? NON_FATAL : FATAL);
			}
		}

		return err;
	}

	error_state metadata_check(string const &path, flags fs) {
		block_manager<>::ptr bm = open_bm(path);

		nested_output out(cerr, 2);
		if (fs.quiet)
			out.disable();

		superblock_reporter sb_rep(out);
		devices_reporter dev_rep(out);
		mapping_reporter mapping_rep(out);

		out << "examining superblock" << end_message();
		{
			nested_output::nest _ = out.push();
			check_superblock(bm, sb_rep);
		}

		if (sb_rep.get_error() == FATAL)
			return FATAL;

		superblock_detail::superblock sb = read_superblock(bm);
		transaction_manager::ptr tm = open_tm(bm);

		if (fs.check_device_tree) {
			out << "examining devices tree" << end_message();
			{
				nested_output::nest _ = out.push();
				device_tree dtree(*tm, sb.device_details_root_,
						  device_tree_detail::device_details_traits::ref_counter());
				check_device_tree(dtree, dev_rep);
			}
		}

		if (fs.check_mapping_tree_level1 && !fs.check_mapping_tree_level2) {
			out << "examining top level of mapping tree" << end_message();
			{
				nested_output::nest _ = out.push();
				dev_tree dtree(*tm, sb.data_mapping_root_,
					       mapping_tree_detail::mtree_traits::ref_counter(tm));
				check_mapping_tree(dtree, mapping_rep);
			}

		} else if (fs.check_mapping_tree_level2) {
			out << "examining mapping tree" << end_message();
			{
				nested_output::nest _ = out.push();
				mapping_tree mtree(*tm, sb.data_mapping_root_,
						   mapping_tree_detail::block_traits::ref_counter(tm->get_sm()));
				check_mapping_tree(mtree, mapping_rep);
			}
		}

		error_state err = NO_ERROR;
		err << sb_rep.get_error() << mapping_rep.get_error() << dev_rep.get_error();

		// if we're checking everything, and there were no errors,
		// then we should check the space maps too.
		if (fs.check_device_tree && fs.check_mapping_tree_level2 && err != FATAL) {
			out << "checking space map counts" << end_message();
			err << check_space_map_counts(fs, out, sb, bm, tm);
		}

		return err;
	}

	void clear_needs_check(string const &path) {
		block_manager<>::ptr bm = open_bm(path, block_manager<>::READ_WRITE);

		superblock_detail::superblock sb = read_superblock(bm);
		sb.set_needs_check_flag(false);
		write_superblock(bm, sb);
	}

	// Returns 0 on success, 1 on failure (this gets returned directly
	// by main).
	int check(string const &path, flags fs) {
		error_state err;
		bool success = false;

		try {
			err = metadata_check(path, fs);

			if (fs.ignore_non_fatal_errors)
				success = (err == FATAL) ? false : true;
			else
				success = (err == NO_ERROR) ? true : false;

			if (success && fs.clear_needs_check_flag_on_success)
				clear_needs_check(path);

		} catch (std::exception &e) {
			if (!fs.quiet)
				cerr << e.what() << endl;

			return 1;
		}

		return !success;
	}
}

//----------------------------------------------------------------

thin_check_cmd::thin_check_cmd()
	: command("thin_check")
{
}

void
thin_check_cmd::usage(std::ostream &out) const
{
	out << "Usage: " << get_name() << " [options] {device|file}" << endl
	    << "Options:" << endl
	    << "  {-q|--quiet}" << endl
	    << "  {-h|--help}" << endl
	    << "  {-V|--version}" << endl
	    << "  {--clear-needs-check-flag}" << endl
	    << "  {--ignore-non-fatal-errors}" << endl
	    << "  {--skip-mappings}" << endl
	    << "  {--super-block-only}" << endl;
}

int
thin_check_cmd::run(int argc, char **argv)
{
	int c;
	flags fs;

	char const shortopts[] = "qhV";
	option const longopts[] = {
		{ "quiet", no_argument, NULL, 'q'},
		{ "help", no_argument, NULL, 'h'},
		{ "version", no_argument, NULL, 'V'},
		{ "super-block-only", no_argument, NULL, 1},
		{ "skip-mappings", no_argument, NULL, 2},
		{ "ignore-non-fatal-errors", no_argument, NULL, 3},
		{ "clear-needs-check-flag", no_argument, NULL, 4 },
		{ NULL, no_argument, NULL, 0 }
	};

	while ((c = getopt_long(argc, argv, shortopts, longopts, NULL)) != -1) {
		switch(c) {
		case 'h':
			usage(cout);
			return 0;

		case 'q':
			fs.quiet = true;
			break;

		case 'V':
			cout << THIN_PROVISIONING_TOOLS_VERSION << endl;
			return 0;

		case 1:
			// super-block-only
			fs.check_device_tree = false;
			fs.check_mapping_tree_level1 = false;
			fs.check_mapping_tree_level2 = false;
			break;

		case 2:
			// skip-mappings
			fs.check_mapping_tree_level2 = false;
			break;

		case 3:
			// ignore-non-fatal-errors
			fs.ignore_non_fatal_errors = true;
			break;

		case 4:
			// clear needs-check flag
			fs.clear_needs_check_flag_on_success = true;
			break;

		default:
			usage(cerr);
			return 1;
		}
	}

	if (argc == optind) {
		if (!fs.quiet) {
			cerr << "No input file provided." << endl;
			usage(cerr);
		}

		exit(1);
	}

	return check(argv[optind], fs);
}

//----------------------------------------------------------------