// Functions used for implementing the complete builtin.
#include "config.h"  // IWYU pragma: keep

#include <stdlib.h>
#include <wchar.h>
#include <memory>
#include <string>
#include <vector>

#include "builtin.h"
#include "common.h"
#include "complete.h"
#include "env.h"
#include "fallback.h"  // IWYU pragma: keep
#include "io.h"
#include "parse_constants.h"
#include "parse_util.h"
#include "parser.h"
#include "proc.h"
#include "reader.h"
#include "wgetopt.h"
#include "wutil.h"  // IWYU pragma: keep

// builtin_complete_* are a set of rather silly looping functions that make sure that all the proper
// combinations of complete_add or complete_remove get called. This is needed since complete allows
// you to specify multiple switches on a single commandline, like 'complete -s a -s b -s c', but the
// complete_add function only accepts one short switch and one long switch.

/// Silly function.
static void builtin_complete_add2(const wchar_t *cmd, int cmd_type, const wchar_t *short_opt,
                                  const wcstring_list_t &gnu_opt, const wcstring_list_t &old_opt,
                                  int result_mode, const wchar_t *condition, const wchar_t *comp,
                                  const wchar_t *desc, int flags) {
    size_t i;
    const wchar_t *s;

    for (s = short_opt; *s; s++) {
        complete_add(cmd, cmd_type, wcstring(1, *s), option_type_short, result_mode, condition,
                     comp, desc, flags);
    }

    for (i = 0; i < gnu_opt.size(); i++) {
        complete_add(cmd, cmd_type, gnu_opt.at(i), option_type_double_long, result_mode, condition,
                     comp, desc, flags);
    }

    for (i = 0; i < old_opt.size(); i++) {
        complete_add(cmd, cmd_type, old_opt.at(i), option_type_single_long, result_mode, condition,
                     comp, desc, flags);
    }

    if (old_opt.empty() && gnu_opt.empty() && wcslen(short_opt) == 0) {
        complete_add(cmd, cmd_type, wcstring(), option_type_args_only, result_mode, condition, comp,
                     desc, flags);
    }
}

/// Silly function.
static void builtin_complete_add(const wcstring_list_t &cmd, const wcstring_list_t &path,
                                 const wchar_t *short_opt, wcstring_list_t &gnu_opt,
                                 wcstring_list_t &old_opt, int result_mode, int authoritative,
                                 const wchar_t *condition, const wchar_t *comp, const wchar_t *desc,
                                 int flags) {
    for (size_t i = 0; i < cmd.size(); i++) {
        builtin_complete_add2(cmd.at(i).c_str(), COMMAND, short_opt, gnu_opt, old_opt, result_mode,
                              condition, comp, desc, flags);

        if (authoritative != -1) {
            complete_set_authoritative(cmd.at(i).c_str(), COMMAND, authoritative);
        }
    }

    for (size_t i = 0; i < path.size(); i++) {
        builtin_complete_add2(path.at(i).c_str(), PATH, short_opt, gnu_opt, old_opt, result_mode,
                              condition, comp, desc, flags);

        if (authoritative != -1) {
            complete_set_authoritative(path.at(i).c_str(), PATH, authoritative);
        }
    }
}

static void builtin_complete_remove_cmd(const wcstring &cmd, int cmd_type, const wchar_t *short_opt,
                                        const wcstring_list_t &gnu_opt,
                                        const wcstring_list_t &old_opt) {
    bool removed = false;
    size_t i;
    for (i = 0; short_opt[i] != L'\0'; i++) {
        complete_remove(cmd, cmd_type, wcstring(1, short_opt[i]), option_type_short);
        removed = true;
    }

    for (i = 0; i < old_opt.size(); i++) {
        complete_remove(cmd, cmd_type, old_opt.at(i), option_type_single_long);
        removed = true;
    }

    for (i = 0; i < gnu_opt.size(); i++) {
        complete_remove(cmd, cmd_type, gnu_opt.at(i), option_type_double_long);
        removed = true;
    }

    if (!removed) {
        // This means that all loops were empty.
        complete_remove_all(cmd, cmd_type);
    }
}

static void builtin_complete_remove(const wcstring_list_t &cmd, const wcstring_list_t &path,
                                    const wchar_t *short_opt, const wcstring_list_t &gnu_opt,
                                    const wcstring_list_t &old_opt) {
    for (size_t i = 0; i < cmd.size(); i++) {
        builtin_complete_remove_cmd(cmd.at(i), COMMAND, short_opt, gnu_opt, old_opt);
    }

    for (size_t i = 0; i < path.size(); i++) {
        builtin_complete_remove_cmd(path.at(i), PATH, short_opt, gnu_opt, old_opt);
    }
}

/// The complete builtin. Used for specifying programmable tab-completions. Calls the functions in
// complete.cpp for any heavy lifting.
int builtin_complete(parser_t &parser, io_streams_t &streams, wchar_t **argv) {
    ASSERT_IS_MAIN_THREAD();
    wgetopter_t w;
    bool res = false;
    int argc = 0;
    int result_mode = SHARED;
    int remove = 0;
    int authoritative = -1;

    wcstring short_opt;
    wcstring_list_t gnu_opt, old_opt;
    const wchar_t *comp = L"", *desc = L"", *condition = L"";

    bool do_complete = false;
    wcstring do_complete_param;

    wcstring_list_t cmd;
    wcstring_list_t path;
    wcstring_list_t wrap_targets;

    static int recursion_level = 0;

    argc = builtin_count_args(argv);

    w.woptind = 0;

    while (!res) {
        static const struct woption long_options[] = {{L"exclusive", no_argument, 0, 'x'},
                                                      {L"no-files", no_argument, 0, 'f'},
                                                      {L"require-parameter", no_argument, 0, 'r'},
                                                      {L"path", required_argument, 0, 'p'},
                                                      {L"command", required_argument, 0, 'c'},
                                                      {L"short-option", required_argument, 0, 's'},
                                                      {L"long-option", required_argument, 0, 'l'},
                                                      {L"old-option", required_argument, 0, 'o'},
                                                      {L"description", required_argument, 0, 'd'},
                                                      {L"arguments", required_argument, 0, 'a'},
                                                      {L"erase", no_argument, 0, 'e'},
                                                      {L"unauthoritative", no_argument, 0, 'u'},
                                                      {L"authoritative", no_argument, 0, 'A'},
                                                      {L"condition", required_argument, 0, 'n'},
                                                      {L"wraps", required_argument, 0, 'w'},
                                                      {L"do-complete", optional_argument, 0, 'C'},
                                                      {L"help", no_argument, 0, 'h'},
                                                      {0, 0, 0, 0}};

        int opt_index = 0;
        int opt =
            w.wgetopt_long(argc, argv, L"a:c:p:s:l:o:d:frxeuAn:C::w:h", long_options, &opt_index);
        if (opt == -1) break;

        switch (opt) {
            case 0: {
                if (long_options[opt_index].flag != 0) break;
                streams.err.append_format(BUILTIN_ERR_UNKNOWN, argv[0],
                                          long_options[opt_index].name);
                builtin_print_help(parser, streams, argv[0], streams.err);
                res = true;
                break;
            }
            case 'x': {
                result_mode |= EXCLUSIVE;
                break;
            }
            case 'f': {
                result_mode |= NO_FILES;
                break;
            }
            case 'r': {
                result_mode |= NO_COMMON;
                break;
            }
            case 'p':
            case 'c': {
                wcstring tmp;
                if (unescape_string(w.woptarg, &tmp, UNESCAPE_SPECIAL)) {
                    if (opt == 'p')
                        path.push_back(tmp);
                    else
                        cmd.push_back(tmp);
                } else {
                    streams.err.append_format(L"%ls: Invalid token '%ls'\n", argv[0], w.woptarg);
                    res = true;
                }
                break;
            }
            case 'd': {
                desc = w.woptarg;
                break;
            }
            case 'u': {
                authoritative = 0;
                break;
            }
            case 'A': {
                authoritative = 1;
                break;
            }
            case 's': {
                short_opt.append(w.woptarg);
                break;
            }
            case 'l': {
                gnu_opt.push_back(w.woptarg);
                break;
            }
            case 'o': {
                old_opt.push_back(w.woptarg);
                break;
            }
            case 'a': {
                comp = w.woptarg;
                break;
            }
            case 'e': {
                remove = 1;
                break;
            }
            case 'n': {
                condition = w.woptarg;
                break;
            }
            case 'w': {
                wrap_targets.push_back(w.woptarg);
                break;
            }
            case 'C': {
                do_complete = true;
                const wchar_t *arg = w.woptarg ? w.woptarg : reader_get_buffer();
                if (arg == NULL) {
                    // This corresponds to using 'complete -C' in non-interactive mode.
                    // See #2361.
                    builtin_missing_argument(parser, streams, argv[0], argv[w.woptind - 1]);
                    return STATUS_BUILTIN_ERROR;
                }
                do_complete_param = arg;
                break;
            }
            case 'h': {
                builtin_print_help(parser, streams, argv[0], streams.out);
                return 0;
            }
            case '?': {
                builtin_unknown_option(parser, streams, argv[0], argv[w.woptind - 1]);
                res = true;
                break;
            }
        }
    }

    if (!res) {
        if (condition && wcslen(condition)) {
            const wcstring condition_string = condition;
            parse_error_list_t errors;
            if (parse_util_detect_errors(condition_string, &errors,
                                         false /* do not accept incomplete */)) {
                streams.err.append_format(L"%ls: Condition '%ls' contained a syntax error", argv[0],
                                          condition);
                for (size_t i = 0; i < errors.size(); i++) {
                    streams.err.append_format(L"\n%s: ", argv[0]);
                    streams.err.append(errors.at(i).describe(condition_string));
                }
                res = true;
            }
        }
    }

    if (!res) {
        if (comp && wcslen(comp)) {
            wcstring prefix;
            if (argv[0]) {
                prefix.append(argv[0]);
                prefix.append(L": ");
            }

            wcstring err_text;
            if (parser.detect_errors_in_argument_list(comp, &err_text, prefix.c_str())) {
                streams.err.append_format(L"%ls: Completion '%ls' contained a syntax error\n",
                                          argv[0], comp);
                streams.err.append(err_text);
                streams.err.push_back(L'\n');
                res = true;
            }
        }
    }

    if (!res) {
        if (do_complete) {
            const wchar_t *token;

            parse_util_token_extent(do_complete_param.c_str(), do_complete_param.size(), &token, 0,
                                    0, 0);

            // Create a scoped transient command line, so that bulitin_commandline will see our
            // argument, not the reader buffer.
            builtin_commandline_scoped_transient_t temp_buffer(do_complete_param);

            if (recursion_level < 1) {
                recursion_level++;

                std::vector<completion_t> comp;
                complete(do_complete_param, &comp, COMPLETION_REQUEST_DEFAULT,
                         env_vars_snapshot_t::current());

                for (size_t i = 0; i < comp.size(); i++) {
                    const completion_t &next = comp.at(i);

                    // Make a fake commandline, and then apply the completion to it.
                    const wcstring faux_cmdline = token;
                    size_t tmp_cursor = faux_cmdline.size();
                    wcstring faux_cmdline_with_completion = completion_apply_to_command_line(
                        next.completion, next.flags, faux_cmdline, &tmp_cursor, false);

                    // completion_apply_to_command_line will append a space unless COMPLETE_NO_SPACE
                    // is set. We don't want to set COMPLETE_NO_SPACE because that won't close
                    // quotes. What we want is to close the quote, but not append the space. So we
                    // just look for the space and clear it.
                    if (!(next.flags & COMPLETE_NO_SPACE) &&
                        string_suffixes_string(L" ", faux_cmdline_with_completion)) {
                        faux_cmdline_with_completion.resize(faux_cmdline_with_completion.size() -
                                                            1);
                    }

                    // The input data is meant to be something like you would have on the command
                    // line, e.g. includes backslashes. The output should be raw, i.e. unescaped. So
                    // we need to unescape the command line. See #1127.
                    unescape_string_in_place(&faux_cmdline_with_completion, UNESCAPE_DEFAULT);
                    streams.out.append(faux_cmdline_with_completion);

                    // Append any description.
                    if (!next.description.empty()) {
                        streams.out.push_back(L'\t');
                        streams.out.append(next.description);
                    }
                    streams.out.push_back(L'\n');
                }

                recursion_level--;
            }
        } else if (w.woptind != argc) {
            streams.err.append_format(_(L"%ls: Too many arguments\n"), argv[0]);
            builtin_print_help(parser, streams, argv[0], streams.err);

            res = true;
        } else if (cmd.empty() && path.empty()) {
            // No arguments specified, meaning we print the definitions of all specified completions
            // to stdout.
            streams.out.append(complete_print());
        } else {
            int flags = COMPLETE_AUTO_SPACE;

            if (remove) {
                builtin_complete_remove(cmd, path, short_opt.c_str(), gnu_opt, old_opt);

            } else {
                builtin_complete_add(cmd, path, short_opt.c_str(), gnu_opt, old_opt, result_mode,
                                     authoritative, condition, comp, desc, flags);
            }

            // Handle wrap targets (probably empty). We only wrap commands, not paths.
            for (size_t w = 0; w < wrap_targets.size(); w++) {
                const wcstring &wrap_target = wrap_targets.at(w);
                for (size_t i = 0; i < cmd.size(); i++) {
                    (remove ? complete_remove_wrapper : complete_add_wrapper)(cmd.at(i),
                                                                              wrap_target);
                }
            }
        }
    }

    return res ? 1 : 0;
}