// Built-in functions

#include <errno.h>
#include <execinfo.h>
#include <fcntl.h>
#include <gc.h>
#include <locale.h>
#include <signal.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/param.h>
#include <time.h>

#include "bools.h"
#include "files.h"
#include "functiontype.h"
#include "integers.h"
#include "metamethods.h"
#include "nums.h"
#include "optionals.h"
#include "paths.h"
#include "print.h"
#include "siphash.h"
#include "stacktrace.h"
#include "stdlib.h"
#include "tables.h"
#include "text.h"
#include "util.h"

#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__) || defined(__APPLE__)
static ssize_t getrandom(void *buf, size_t buflen, unsigned int flags) {
    (void)flags;
    arc4random_buf(buf, buflen);
    return buflen;
}
#elif defined(__linux__)
// Use getrandom()
#   include <sys/random.h>
#else
    #error "Unsupported platform for secure random number generation"
#endif

public bool USE_COLOR;

static _Noreturn void signal_handler(int sig, siginfo_t *info, void *userdata)
{
    (void)info, (void)userdata;
    assert(sig == SIGILL);
    fflush(stdout);
    if (USE_COLOR) fputs("\x1b[31;7m ===== ILLEGAL INSTRUCTION ===== \n\n\x1b[m", stderr);
    else fputs("===== ILLEGAL INSTRUCTION =====\n\n", stderr);
    print_stacktrace(stderr, 3);
    fflush(stderr);
    raise(SIGABRT);
    _exit(1);
}

public void tomo_init(void)
{
   GC_INIT();
   USE_COLOR = getenv("COLOR") ? strcmp(getenv("COLOR"), "1") == 0 : isatty(STDOUT_FILENO);
   if (getenv("NO_COLOR") && getenv("NO_COLOR")[0] != '\0')
       USE_COLOR = false;

   setlocale(LC_ALL, "");
   getrandom(TOMO_HASH_KEY, sizeof(TOMO_HASH_KEY), 0);

   struct sigaction sigact;
   sigact.sa_sigaction = signal_handler;
   sigemptyset(&sigact.sa_mask);
   sigact.sa_flags = 0;
   sigaction(SIGILL, &sigact, (struct sigaction *)NULL);
}

static bool parse_single_arg(const TypeInfo_t *info, char *arg, void *dest)
{
    if (!arg) return false;

    if (info->tag == OptionalInfo && streq(arg, "none"))
        return true;

    while (info->tag == OptionalInfo)
        info = info->OptionalInfo.type;

    if (info == &Int$info) {
        OptionalInt_t parsed = Int$from_str(arg);
        if (parsed.small != 0)
            *(OptionalInt_t*)dest = parsed;
        return parsed.small != 0;
    } else if (info == &Int64$info) {
        OptionalInt64_t parsed = Int64$parse(Text$from_str(arg));
        if (!parsed.is_none)
            *(OptionalInt64_t*)dest = parsed;
        return !parsed.is_none;
    } else if (info == &Int32$info) {
        OptionalInt32_t parsed = Int32$parse(Text$from_str(arg));
        if (!parsed.is_none)
            *(OptionalInt32_t*)dest = parsed;
        return !parsed.is_none;
    } else if (info == &Int16$info) {
        OptionalInt16_t parsed = Int16$parse(Text$from_str(arg));
        if (!parsed.is_none)
            *(OptionalInt16_t*)dest = parsed;
        return !parsed.is_none;
    } else if (info == &Int8$info) {
        OptionalInt8_t parsed = Int8$parse(Text$from_str(arg));
        if (!parsed.is_none)
            *(OptionalInt8_t*)dest = parsed;
        return !parsed.is_none;
    } else if (info == &Bool$info) {
        OptionalBool_t parsed = Bool$parse(Text$from_str(arg));
        if (parsed != NONE_BOOL)
            *(OptionalBool_t*)dest = parsed;
        return parsed != NONE_BOOL;
    } else if (info == &Num$info) {
        OptionalNum_t parsed = Num$parse(Text$from_str(arg));
        if (!isnan(parsed))
            *(OptionalNum_t*)dest = parsed;
        return !isnan(parsed);
    } else if (info == &Num32$info) {
        OptionalNum32_t parsed = Num32$parse(Text$from_str(arg));
        if (!isnan(parsed))
            *(OptionalNum32_t*)dest = parsed;
        return !isnan(parsed);
    } else if (info == &Path$info) {
        *(OptionalPath_t*)dest = Path$from_str(arg);
        return true;
    } else if (info->tag == TextInfo) {
        *(OptionalText_t*)dest = Text$from_str(arg);
        return true;
    } else if (info->tag == EnumInfo) {
        for (int t = 0; t < info->EnumInfo.num_tags; t++) {
            NamedType_t named = info->EnumInfo.tags[t];
            size_t len = strlen(named.name);
            if (strncmp(arg, named.name, len) == 0 && (arg[len] == '\0' || arg[len] == ':')) {
                *(int32_t*)dest = (t + 1);

                // Simple tag (no associated data):
                if (!named.type || (named.type->tag == StructInfo && named.type->StructInfo.num_fields == 0))
                    return true;

                // Single-argument tag:
                if (arg[len] != ':')
                    print_err("Invalid value for ", t, ".", named.name, ": ", arg);
                size_t offset = sizeof(int32_t);
                if (named.type->align > 0 && offset % (size_t)named.type->align > 0)
                    offset += (size_t)named.type->align - (offset % (size_t)named.type->align);
                if (!parse_single_arg(named.type, arg + len + 1, dest + offset))
                    return false;
                return true;
            }
        }
        print_err("Invalid value for ", info->EnumInfo.name, ": ", arg);
    } else if (info->tag == StructInfo) {
        if (info->StructInfo.num_fields == 0)
            return true;
        else if (info->StructInfo.num_fields == 1)
            return parse_single_arg(info->StructInfo.fields[0].type, arg, dest);

        Text_t t = generic_as_text(NULL, false, info);
        print_err("Unsupported multi-argument struct type for argument parsing: ", t);
    } else if (info->tag == ListInfo) {
        print_err("List arguments must be specified as `--flag ...` not `--flag=...`");
    } else if (info->tag == TableInfo) {
        print_err("Table arguments must be specified as `--flag ...` not `--flag=...`");
    } else {
        Text_t t = generic_as_text(NULL, false, info);
        print_err("Unsupported type for argument parsing: ", t);
    }
    return false;
}

static List_t parse_list(const TypeInfo_t *item_info, int n, char *args[])
{
    int64_t padded_size = item_info->size;
    if ((padded_size % item_info->align) > 0)
        padded_size = padded_size + item_info->align - (padded_size % item_info->align);

    List_t items = {
        .stride=padded_size,
        .length=n,
        .data=GC_MALLOC((size_t)(padded_size*n)),
    };
    for (int i = 0; i < n; i++) {
        bool success = parse_single_arg(item_info, args[i], items.data + items.stride*i);
        if (!success)
            print_err("Couldn't parse argument: ", args[i]);
    }
    return items;
}

// Arguments take the form key=value, with a guarantee that there is an '='
static Table_t parse_table(const TypeInfo_t *table, int n, char *args[])
{
    const TypeInfo_t *key = table->TableInfo.key, *value = table->TableInfo.value;
    int64_t padded_size = key->size;
    if ((padded_size % value->align) > 0)
        padded_size = padded_size + value->align - (padded_size % value->align);
    int64_t value_offset = padded_size;
    padded_size += value->size;
    if ((padded_size % key->align) > 0)
        padded_size = padded_size + key->align - (padded_size % key->align);

    List_t entries = {
        .stride=padded_size,
        .length=n,
        .data=GC_MALLOC((size_t)(padded_size*n)),
    };
    for (int i = 0; i < n; i++) {
        char *key_arg = args[i];
        char *equals = strchr(key_arg, '=');
        assert(equals);
        char *value_arg = equals + 1;
        *equals = '\0';

        bool success = parse_single_arg(key, key_arg, entries.data + entries.stride*i);
        if (!success)
            print_err("Couldn't parse table key: ", key_arg);

        success = parse_single_arg(value, value_arg, entries.data + entries.stride*i + value_offset);
        if (!success)
            print_err("Couldn't parse table value: ", value_arg);

        *equals = '=';
    }
    return Table$from_entries(entries, table);
}

#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstack-protector"
#endif
public void _tomo_parse_args(int argc, char *argv[], Text_t usage, Text_t help, int spec_len, cli_arg_t spec[spec_len])
{
    bool populated_args[spec_len];
    bool used_args[argc];
    memset(populated_args, 0, sizeof(populated_args));
    memset(used_args, 0, sizeof(used_args));
    for (int i = 1; i < argc; ) {
        if (argv[i][0] == '-' && argv[i][1] == '-') {
            if (argv[i][2] == '\0') { // "--" signals the rest of the arguments are literal
                used_args[i] = true;
                i += 1;
                break;
            }

            for (int s = 0; s < spec_len; s++) {
                const TypeInfo_t *non_opt_type = spec[s].type;
                while (non_opt_type->tag == OptionalInfo)
                    non_opt_type = non_opt_type->OptionalInfo.type;

                if (non_opt_type == &Bool$info
                    && strncmp(argv[i], "--no-", strlen("--no-")) == 0
                    && strcmp(argv[i] + strlen("--no-"), spec[s].name) == 0) {
                    *(OptionalBool_t*)spec[s].dest = false;
                    populated_args[s] = true;
                    used_args[i] = true;
                    goto next_arg;
                }

                if (strncmp(spec[s].name, argv[i] + 2, strlen(spec[s].name)) != 0)
                    continue;

                char after_name = argv[i][2+strlen(spec[s].name)];
                if (after_name == '\0') { // --foo val
                    used_args[i] = true;
                    if (non_opt_type->tag == ListInfo) {
                        int num_args = 0;
                        while (i + 1 + num_args < argc) {
                            if (argv[i+1+num_args][0] == '-')
                                break;
                            used_args[i+1+num_args] = true;
                            num_args += 1;
                        }
                        populated_args[s] = true;
                        *(OptionalList_t*)spec[s].dest = parse_list(non_opt_type->ListInfo.item, num_args, &argv[i+1]);
                    } else if (non_opt_type->tag == TableInfo) {
                        int num_args = 0;
                        while (i + 1 + num_args < argc) {
                            if (argv[i+1+num_args][0] == '-' || !strchr(argv[i+1+num_args], '='))
                                break;
                            used_args[i+1+num_args] = true;
                            num_args += 1;
                        }
                        populated_args[s] = true;
                        *(OptionalTable_t*)spec[s].dest = parse_table(non_opt_type, num_args, &argv[i+1]);
                    } else if (non_opt_type == &Bool$info) { // --flag
                        populated_args[s] = true;
                        *(OptionalBool_t*)spec[s].dest = true;
                    } else {
                        if (i + 1 >= argc)
                            print_err("Missing argument: ", argv[i], "\n", usage);
                        used_args[i+1] = true;
                        populated_args[s] = parse_single_arg(spec[s].type, argv[i+1], spec[s].dest);
                        if (!populated_args[s])
                            print_err("Couldn't parse argument: ", argv[i], " ", argv[i+1], "\n", usage);
                    }
                    goto next_arg;
                } else if (after_name == '=') { // --foo=val
                    used_args[i] = true;
                    populated_args[s] = parse_single_arg(spec[s].type, 2 + argv[i] + strlen(spec[s].name) + 1, spec[s].dest);
                    if (!populated_args[s])
                        print_err("Couldn't parse argument: ", argv[i], "\n", usage);
                    goto next_arg;
                } else {
                    continue;
                }
            }

            if (streq(argv[i], "--help")) {
                say(help, true);
                exit(0);
            }
            print_err("Unrecognized argument: ", argv[i], "\n", usage);
        } else if (argv[i][0] == '-' && argv[i][1] && argv[i][1] != '-' && !isdigit(argv[i][1])) { // Single flag args
            used_args[i] = true;
            for (char *f = argv[i] + 1; *f; f++) {
                char flag[] = {'-', *f, 0};
                for (int s = 0; s < spec_len; s++) {
                    if (spec[s].name[0] != *f || strlen(spec[s].name) > 1)
                        continue;

                    const TypeInfo_t *non_opt_type = spec[s].type;
                    while (non_opt_type->tag == OptionalInfo)
                        non_opt_type = non_opt_type->OptionalInfo.type;

                    if (non_opt_type->tag == ListInfo) {
                        if (f[1]) print_err("No value provided for ", flag, "\n", usage);
                        int num_args = 0;
                        while (i + 1 + num_args < argc) {
                            if (argv[i+1+num_args][0] == '-')
                                break;
                            used_args[i+1+num_args] = true;
                            num_args += 1;
                        }
                        populated_args[s] = true;
                        *(OptionalList_t*)spec[s].dest = parse_list(non_opt_type->ListInfo.item, num_args, &argv[i+1]);
                    } else if (non_opt_type->tag == TableInfo) {
                        int num_args = 0;
                        while (i + 1 + num_args < argc) {
                            if (argv[i+1+num_args][0] == '-' || !strchr(argv[i+1+num_args], '='))
                                break;
                            used_args[i+1+num_args] = true;
                            num_args += 1;
                        }
                        populated_args[s] = true;
                        *(OptionalTable_t*)spec[s].dest = parse_table(non_opt_type, num_args, &argv[i+1]);
                    } else if (non_opt_type == &Bool$info) { // -f
                        populated_args[s] = true;
                        *(OptionalBool_t*)spec[s].dest = true;
                    } else {
                        if (f[1] || i+1 >= argc) print_err("No value provided for ", flag, "\n", usage);
                        used_args[i+1] = true;
                        populated_args[s] = parse_single_arg(spec[s].type, argv[i+1], spec[s].dest);
                        if (!populated_args[s])
                            print_err("Couldn't parse argument: ", argv[i], " ", argv[i+1], "\n", usage);
                    }
                    goto next_flag;
                }

                if (*f == 'h') {
                    say(help, true);
                    exit(0);
                }
                print_err("Unrecognized flag: ", flag, "\n", usage);
              next_flag:;
            }
        } else {
            // Handle positional args later
            i += 1;
            continue;
        }

      next_arg:
        while (used_args[i] && i < argc)
            i += 1;
    }

    // Get remaining positional arguments
    bool ignore_dashes = false;
    for (int i = 1, s = 0; i < argc; i++) {
        if (!ignore_dashes && streq(argv[i], "--")) {
            ignore_dashes = true;
            continue;
        }
        if (used_args[i]) continue;

        while (populated_args[s]) {
          next_non_bool_flag:
            ++s;
            if (s >= spec_len)
                print_err("Extra argument: ", argv[i], "\n", usage);
        }

        const TypeInfo_t *non_opt_type = spec[s].type;
        while (non_opt_type->tag == OptionalInfo)
            non_opt_type = non_opt_type->OptionalInfo.type;

        // You can't specify boolean flags positionally
        if (non_opt_type == &Bool$info)
            goto next_non_bool_flag;

        if (non_opt_type->tag == ListInfo) {
            int num_args = 0;
            while (i + num_args < argc) {
                if (!ignore_dashes && (argv[i+num_args][0] == '-' && !isdigit(argv[i+num_args][1])))
                    break;
                used_args[i+num_args] = true;
                num_args += 1;
            }
            populated_args[s] = true;
            *(OptionalList_t*)spec[s].dest = parse_list(non_opt_type->ListInfo.item, num_args, &argv[i]);
        } else if (non_opt_type->tag == TableInfo) {
            int num_args = 0;
            while (i + num_args < argc) {
                if ((argv[i+num_args][0] == '-' && !isdigit(argv[i+num_args][1])) || !strchr(argv[i+num_args], '='))
                    break;
                used_args[i+num_args] = true;
                num_args += 1;
            }
            populated_args[s] = true;
            *(OptionalTable_t*)spec[s].dest = parse_table(non_opt_type, num_args, &argv[i]);
        } else {
            populated_args[s] = parse_single_arg(spec[s].type, argv[i], spec[s].dest);
        }

        if (!populated_args[s])
            print_err("Invalid value for ", spec[s].name, ": ", argv[i], "\n", usage);
    }

    for (int s = 0; s < spec_len; s++) {
        if (!populated_args[s] && spec[s].required) {
            if (spec[s].type->tag == ListInfo)
                *(OptionalList_t*)spec[s].dest = (List_t){};
            else if (spec[s].type->tag == TableInfo)
                *(OptionalTable_t*)spec[s].dest = (Table_t){};
            else
                print_err("The required argument '", spec[s].name, "' was not provided\n", usage);
        }
    }
}
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif

public _Noreturn void fail_text(Text_t message)
{
    fail(message);
}

public Text_t builtin_last_err()
{
    return Text$from_str(strerror(errno));
}

static int _inspect_depth = 0;
static file_t *file = NULL;

__attribute__((nonnull))
public void start_inspect(const char *filename, int64_t start, int64_t end)
{
    if (file == NULL || strcmp(file->filename, filename) != 0)
        file = load_file(filename);

    if (file) {
        const char *spaces = "                                                  ";
        int64_t first_line_len = (int64_t)strcspn(file->text + start, "\r\n");
        const char *slash = strrchr(filename, '/');
        const char *file_base = slash ? slash + 1 : filename;

        int64_t line_num = get_line_number(file, file->text + start);
        fprintf(stdout, USE_COLOR ? "%.*s\x1b[33;1m>> \x1b[m%.*s   %.*s\x1b[32;2m[%s:%ld]\x1b[m\n" : "%.*s>> %.*s   %.*s[%s:%ld]\n",
                3*_inspect_depth, spaces, first_line_len, file->text + start,
                MAX(0, 35-first_line_len-3*_inspect_depth), spaces, file_base, line_num);

        // For multi-line expressions, dedent each and print it on a new line with ".. " in front:
        if (end > start + first_line_len) {
            const char *line_start = get_line(file, line_num);
            int64_t indent_len = (int64_t)strspn(line_start, " \t");
            for (const char *line = file->text + start + first_line_len; line < file->text + end; line += strcspn(line, "\r\n")) {
                line += strspn(line, "\r\n");
                if ((int64_t)strspn(line, " \t") >= indent_len)
                    line += indent_len;
                fprintf(stdout, USE_COLOR ? "%.*s\x1b[33m.. \x1b[m%.*s\n" : "%.*s.. %.*s\n",
                        3*_inspect_depth, spaces, strcspn(line, "\r\n"), line);
            }
        }
    }
    _inspect_depth += 1;
}

public void end_inspect(const void *expr, const TypeInfo_t *type)
{
    _inspect_depth -= 1;

    if (type->metamethods.as_text) {
        Text_t expr_text = generic_as_text(expr, USE_COLOR, type);
        Text_t type_name = generic_as_text(NULL, false, type);
        for (int i = 0; i < 3*_inspect_depth; i++) fputc(' ', stdout);
        fprint(stdout, USE_COLOR ? "\x1b[33;1m=\x1b[0m " : " =", expr_text, USE_COLOR ? " \x1b[2m: \x1b[36m" : " : ", type_name, USE_COLOR ? "\033[m" : "");
    }
}

__attribute__((nonnull))
public void test_value(const char *filename, int64_t start, int64_t end, const void *expr, const void *expected, const TypeInfo_t *type)
{
    Text_t expr_text = generic_as_text(expr, USE_COLOR, type);
    Text_t expected_text = generic_as_text(expected, USE_COLOR, type);

    bool success = Text$equal_values(expr_text, expected_text);
    if (!success) {
        print_stacktrace(stderr, 2);
        fprint(stderr, "");
        fflush(stderr);

        start_inspect(filename, start, end);
        end_inspect(expr, type);
        fflush(stdout);

        if (USE_COLOR) {
            fprint(stderr, 
                    "\n\x1b[31;7m ==================== TEST FAILED ==================== \x1b[0;1m\n\n"
                    "You expected: \x1b[m", expected_text, "\x1b[0m\n"
                    "\x1b[1m   But I got:\x1b[m ", expr_text, "\n");
        } else {
            fprint(stderr, 
                    "\n==================== TEST FAILED ====================\n\n"
                    "You expected: ", expected_text, "\n"
                    "   But I got: ", expr_text, "\n");
        }

        fflush(stderr);
        raise(SIGABRT);
    }
}

public void say(Text_t text, bool newline)
{
    Text$print(stdout, text);
    if (newline)
        fputc('\n', stdout);
    fflush(stdout);
}

public _Noreturn void tomo_exit(Text_t text, int32_t status)
{
    if (text.length > 0)
        say(text, true);
    _exit(status);
}

public OptionalText_t ask(Text_t prompt, bool bold, bool force_tty)
{
    OptionalText_t ret = NONE_TEXT;
    FILE *out = stdout;
    FILE *in = stdin;

    char *line = NULL;
    size_t bufsize = 0;
    ssize_t length = 0;
    char *gc_input = NULL;

    if (force_tty && !isatty(STDOUT_FILENO)) {
        out = fopen("/dev/tty", "w");
        if (!out) goto cleanup;
    }

    if (bold) fputs("\x1b[1m", out);
    Text$print(out, prompt);
    if (bold) fputs("\x1b[m", out);
    fflush(out);

    if (force_tty && !isatty(STDIN_FILENO)) {
        in = fopen("/dev/tty", "r");
        if (!in) {
            fputs("\n", out); // finish the line, since the user can't
            goto cleanup;
        }
    }

    length = getline(&line, &bufsize, in);
    if (length == -1) {
        fputs("\n", out); // finish the line, since we didn't get any input
        goto cleanup;
    }

    if (length > 0 && line[length-1] == '\n') {
        line[length-1] = '\0';
        --length;
    }

    gc_input = GC_MALLOC_ATOMIC((size_t)(length + 1));
    memcpy(gc_input, line, (size_t)(length + 1));

    ret = Text$from_strn(gc_input, (size_t)(length));

  cleanup:
    if (out && out != stdout) fclose(out);
    if (in && in != stdin) fclose(in);
    return ret;
}

public bool pop_flag(char **argv, int *i, const char *flag, Text_t *result)
{
    if (argv[*i][0] != '-' || argv[*i][1] != '-') {
        return false;
    } else if (streq(argv[*i] + 2, flag)) {
        *result = EMPTY_TEXT;
        argv[*i] = NULL;
        *i += 1;
        return true;
    } else if (strncmp(argv[*i] + 2, "no-", 3) == 0 && streq(argv[*i] + 5, flag)) {
        *result = Text("no");
        argv[*i] = NULL;
        *i += 1;
        return true;
    } else if (strncmp(argv[*i] + 2, flag, strlen(flag)) == 0 && argv[*i][2 + strlen(flag)] == '=') {
        *result = Text$from_str(argv[*i] + 2 + strlen(flag) + 1);
        argv[*i] = NULL;
        *i += 1;
        return true;
    } else {
        return false;
    }
}

public void sleep_num(double seconds)
{
    struct timespec ts;
    ts.tv_sec = (time_t)seconds;
    ts.tv_nsec = (long)((seconds - (double)ts.tv_sec) * 1e9);
    nanosleep(&ts, NULL);
}

public OptionalText_t getenv_text(Text_t name)
{
    const char *val = getenv(Text$as_c_string(name));
    return val ? Text$from_str(val) : NONE_TEXT;
}

public void setenv_text(Text_t name, Text_t value)
{
    setenv(Text$as_c_string(name), Text$as_c_string(value), 1);
}

// vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0