/**
 * Copyright (c) 2007-2012, Timothy Stack
 *
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * 
 * * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * * Neither the name of Timothy Stack nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>

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

#include <random>
#include <tuple>
#include <vector>
#include <algorithm>

#include "base/string_util.hh"
#include "auto_fd.hh"
#include "line_buffer.hh"

using namespace std;

int main(int argc, char *argv[])
{
	int c, rnd_iters = 5, retval = EXIT_SUCCESS;
	vector<tuple<int, off_t, ssize_t> > index;
	auto_fd fd = auto_fd(STDIN_FILENO), fd_cmp;
	int offseti = 0;
	off_t offset = 0;
	int count = 1000;
	struct stat st;

	while ((c = getopt(argc, argv, "o:i:n:c:")) != -1) {
		switch (c) {
			case 'o':
				if (sscanf(optarg, "%d", &offseti) != 1) {
					fprintf(stderr,
							"error: offset is not an integer -- %s\n",
							optarg);
					retval = EXIT_FAILURE;
				} else {
					offset = offseti;
				}
				break;
			case 'n':
				if (sscanf(optarg, "%d", &rnd_iters) != 1) {
					fprintf(stderr,
							"error: offset is not an integer -- %s\n",
							optarg);
					retval = EXIT_FAILURE;
				}
				break;
			case 'c':
				if (sscanf(optarg, "%d", &count) != 1) {
					fprintf(stderr,
							"error: count is not an integer -- %s\n",
							optarg);
					retval = EXIT_FAILURE;
				}
				break;
			case 'i': {
				FILE *file;

				if ((file = fopen(optarg, "r")) == NULL) {
					perror("open");
					retval = EXIT_FAILURE;
				} else {
					int line_number = 1, line_offset;
					off_t last_offset;
					ssize_t line_size;

					while (fscanf(file, "%d", &line_offset) == 1) {
					    if (line_number > 1) {
					        line_size = line_offset - last_offset;
                            index.emplace_back(line_number - 1,
                                               last_offset,
                                               line_size);
                        }
					    last_offset = line_offset;
						line_number += 1;
					}
					fclose(file);
					file = NULL;
				}
			}
				break;
			default:
				retval = EXIT_FAILURE;
				break;
		}
	}

	argc -= optind;
	argv += optind;

	if (retval != EXIT_SUCCESS) {
	} else if ((argc == 0) && (index.size() > 0)) {
		fprintf(stderr, "error: cannot randomize stdin\n");
		retval = EXIT_FAILURE;
	} else if ((argc > 0) && (fd = open(argv[0], O_RDONLY)) == -1) {
		perror("open");
		retval = EXIT_FAILURE;
	} else if ((argc > 0) && (fstat(fd, &st) == -1)) {
		perror("fstat");
		retval = EXIT_FAILURE;
	} else if ((argc > 1) && (fd_cmp = open(argv[1], O_RDONLY)) == -1) {
		perror("open-cmp");
		retval = EXIT_FAILURE;
	} else if ((argc > 1) && (fstat(fd_cmp, &st) == -1)) {
		perror("fstat-cmp");
		retval = EXIT_FAILURE;
	} else {
		try {
		    file_range last_range{offset};
			line_buffer lb;
			char *maddr;

			int fd2 = (argc > 1) ? fd_cmp.get() : fd.get();
			assert(fd2 >= 0);
			lb.set_fd(fd);
			if (index.size() == 0) {
				while (count) {
                    auto load_result = lb.load_next_line(last_range);

                    if (load_result.isErr()) {
                        break;
                    }

                    auto li = load_result.unwrap();

                    if (li.li_file_range.empty()) {
                        break;
                    }

                    auto read_result = lb.read_range(li.li_file_range);

                    if (read_result.isErr()) {
                        break;
                    }

                    auto sbr = read_result.unwrap();

                    if (!li.li_valid_utf) {
                        scrub_to_utf8(sbr.get_writable_data(), sbr.length());
                    }

					printf("%.*s", (int) sbr.length(), sbr.get_data());
					if ((off_t) (li.li_file_range.fr_offset + li.li_file_range.fr_size) < offset) {
                        printf("\n");
                    }
					last_range = li.li_file_range;
					count -= 1;
				}
			} else if ((maddr = (char *) mmap(NULL,
											  st.st_size,
											  PROT_READ,
											  MAP_FILE | MAP_PRIVATE,
											  fd2,
											  0)) == MAP_FAILED) {
				perror("mmap");
				retval = EXIT_FAILURE;
			} else {
				file_range range;

				while (true) {
                    auto load_result = lb.load_next_line(range);

                    if (load_result.isErr()) {
                        return EXIT_FAILURE;
                    }

                    auto li = load_result.unwrap();

                    range = li.li_file_range;

                    if (range.empty()) {
                        break;
                    }
				}
				do {
					size_t lpc;

					std::random_device rd;
					std::mt19937 g(rd());
					std::shuffle(index.begin(), index.end(), g);
					for (lpc = 0; lpc < index.size(); lpc++) {
					    const auto &index_tuple = index[lpc];

						auto read_result = lb.read_range(
						    {get<1>(index_tuple), get<2>(index_tuple)});

						assert(read_result.isOk());

						auto sbr = read_result.unwrap();

						assert(memcmp(sbr.get_data(),
									  &maddr[get<1>(index_tuple)],
									  sbr.length()) == 0);
					}

					rnd_iters -= 1;
				} while (rnd_iters);

				printf("All done\n");
			}
		}
		catch (line_buffer::error &e) {
			fprintf(stderr, "error: %s\n", strerror(e.e_err));
			retval = EXIT_FAILURE;
		}
	}

	return retval;
}
