#include <sys/types.h>

#include <assert.h>
#include <limits.h>
#include <math.h>
#include <setjmp.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <unistd.h>     // TODO: Unix only
extern char **environ;  // TODO: Unix only

#include "scheme.h"

#define BITSIZEOF(t) (sizeof(t) * CHAR_BIT)

value_t envst_language(void)
{
    struct accum acc = ACCUM_EMPTY;

    accum_elt(&acc, symbol("language"));
    accum_name_value(&acc, "implementation-name",
                     string_from_cstr("Up Scheme"));
    accum_name_value(&acc, "implementation-version",
                     string_from_cstr("0.1.0"));
    return acc.list;
}

value_t envst_language_c(void)
{
    struct accum acc = ACCUM_EMPTY;

    accum_elt(&acc, symbol("language"));
    accum_name_value(&acc, "implementation-name",
                     string_from_cstr(SCHEME_C_COMPILER_NAME));
    accum_name_value(&acc, "implementation-version",
                     string_from_cstr(SCHEME_C_COMPILER_VERSION));
    return acc.list;
}

static value_t get_features_list(void)
{
    static struct accum acc;
    static int initialized;

    if (!initialized) {
        initialized = 1;
        accum_init(&acc);
#ifdef BITS64
        accum_elt(&acc, symbol("bits-64"));
#endif
#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
        accum_elt(&acc, symbol("big-endian"));
#endif
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
        accum_elt(&acc, symbol("little-endian"));
#endif
        accum_elt(&acc, symbol("r7rs"));
    }
    return acc.list;
}

static value_t build_c_type_bits_list(void)
{
    struct accum acc;

    accum_init(&acc);
    accum_name_value1(&acc, "int", fixnum(BITSIZEOF(int)));
    accum_name_value1(&acc, "long", fixnum(BITSIZEOF(long)));
    accum_name_value1(&acc, "float", fixnum(BITSIZEOF(float)));
    accum_name_value1(&acc, "double", fixnum(BITSIZEOF(double)));
    accum_name_value1(&acc, "pointer", fixnum(BITSIZEOF(void *)));
    accum_name_value1(&acc, "size_t", fixnum(BITSIZEOF(size_t)));
    accum_name_value1(&acc, "value_t", fixnum(BITSIZEOF(value_t)));
    return acc.list;
}

static value_t build_stable_specs_list(void)
{
    struct accum acc;
    const int *p;

    accum_init(&acc);
    for (p = upscheme_stable_specs; *p; p++) {
        accum_elt(&acc, fixnum(*p));
    }
    return acc.list;
}

static const char *get_build_platform(void)
{
    const char *kernel;
    const char *userland;
    const char *computer;
    const char *endian;

    // <http://predef.sf.net/>

    kernel = userland = computer = endian = "unknown";

#ifdef __FreeBSD__
    kernel = userland = "freebsd";
#endif
#ifdef __FreeBSD_kernel__
    kernel = "freebsd";
#endif
#ifdef __GLIBC__
    userland = "gnu";
#endif
#ifdef __OpenBSD__
    userland = kernel = "openbsd";
#endif
#ifdef __NetBSD__
    userland = kernel = "netbsd";
#endif
#ifdef __DragonFly__
    userland = kernel = "dragonfly";
#endif
#ifdef __sun
    userland = kernel = "solaris";
#endif
#ifdef __minix
    userland = kernel = "minix";
#endif
#ifdef __HAIKU__
    userland = "beos";
    kernel = "haiku";
#endif
#ifdef __APPLE__
    userland = kernel = "darwin";
#endif
#ifdef _WIN32
    kernel = userland = "windows-nt";
#endif

#ifdef __i386
    computer = "x86";
#endif
#ifdef _M_IX86
    computer = "x86";
#endif
#ifdef __X86__
    computer = "x86";
#endif
#ifdef __I86__
    computer = "x86";
#endif
#ifdef __amd64
    computer = "x86-64";
#endif
#ifdef __x86_64
    computer = "x86-64";
#endif
#ifdef _M_AMD64
    computer = "x86-64";
#endif
#ifdef __ppc__
    computer = "ppc";
#endif
#ifdef _M_PPC
    computer = "ppc";
#endif
#ifdef __PPC64__
    computer = "ppc-64";
#endif
#ifdef __mips64__
    computer = "mips-64";
#endif
#ifdef __arm__
    computer = "arm";
#endif
#ifdef __aarch64__
    computer = "arm";
#endif
#ifdef __sparc
    computer = "sparc";
#endif
#ifdef __sparc__
    computer = "sparc";
#endif
#ifdef __sparc64__
    computer = "sparc";
#endif
#ifdef __mips__
    computer = "mips";
#endif
#ifdef __mips64__
    computer = "mips";
#endif

#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
    endian = "big";
#endif
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
    endian = "little";
#endif

    return kernel;
}

static value_t build_srfi_list(void)
{
    struct accum acc = ACCUM_EMPTY;

    accum_elt(&acc, fixnum(0));
    accum_elt(&acc, fixnum(1));
    accum_elt(&acc, fixnum(6));
    accum_elt(&acc, fixnum(22));
    accum_elt(&acc, fixnum(27));
    accum_elt(&acc, fixnum(174));
    accum_elt(&acc, fixnum(175));
    accum_elt(&acc, fixnum(176));
    return acc.list;
}

static value_t list_from_cstrv(const char **sv)
{
    struct accum acc = ACCUM_EMPTY;

    for (; *sv; sv++) {
        accum_elt(&acc, string_from_cstr(*sv));
    }
    return acc.list;
}

value_t get_version_alist(void)
{
    static struct accum acc;
    static int initialized;

    if (!initialized) {
        initialized = 1;
        accum_init(&acc);
        accum_name_value1(&acc, "command", string_from_cstr("upscheme"));
        accum_name_value1(&acc, "release", string_from_cstr(env_release));
        accum_name_value1(&acc, "release.date",
                          string_from_cstr(env_release_date));
        accum_name_value(&acc, "encodings", fl_cons(symbol("utf-8"), FL_NIL));
        accum_name_value(
        &acc, "languages",
        fl_cons(symbol("scheme"), fl_cons(symbol("r7rs"), FL_NIL)));
        accum_name_value1(&acc, "scheme.id", symbol("upscheme"));
        accum_name_value(&acc, "scheme.srfi", build_srfi_list());
        accum_name_value(&acc, "scheme.features", get_features_list());
        accum_name_value1(&acc, "build.date",
                          string_from_cstr(env_build_date));
        accum_name_value1(&acc, "build.platform",
                          string_from_cstr(get_build_platform()));
        accum_name_value1(&acc, "build.git.branch",
                          string_from_cstr(env_build_git_branch));
        accum_name_value1(&acc, "build.git.commit",
                          string_from_cstr(env_build_git_commit));
        accum_name_value(&acc, "build.git.modified",
                         list_from_cstrv(env_build_git_modified));
        accum_name_value(&acc, "c.type-bits", build_c_type_bits_list());
        accum_name_value1(&acc, "c.version",
                          string_from_cstr(SCHEME_C_COMPILER_NAME
                                           " " SCHEME_C_COMPILER_VERSION));
        accum_name_value(&acc, "c.compile",
                         list_from_cstrv(env_build_c_compile));
        accum_name_value(&acc, "c.link", list_from_cstrv(env_build_c_link));
        accum_name_value(&acc, "upscheme.stable-specs",
                         build_stable_specs_list());
        accum_name_value1(&acc, "upscheme.unstable-spec",
                          fixnum(upscheme_unstable_spec));
    }
    return acc.list;
}

value_t builtin_features(value_t *args, uint32_t nargs)
{
    (void)args;
    argcount("features", nargs, 0);
    return get_features_list();
}

value_t builtin_version_alist(value_t *args, uint32_t nargs)
{
    (void)args;
    argcount("version-alist", nargs, 0);
    return get_version_alist();
}

value_t builtin_script_file(value_t *args, uint32_t nargs)
{
    (void)args;
    argcount("script-file", nargs, 0);
    return script_file ? string_from_cstr(script_file) : FL_F;
}

value_t builtin_script_directory(value_t *args, uint32_t nargs)
{
    char *path;
    char *pathslash;
    value_t obj;

    (void)args;
    argcount("script-directory", nargs, 0);
    if (!script_file) {
        return FL_F;
    }
    path = strdup(script_file);
    path_to_dirname(path);
    pathslash = calloc(1, strlen(path) + 2);
    memcpy(pathslash, path, strlen(path));
    pathslash[strlen(path)] = '/';
    obj = string_from_cstr(pathslash);
    free(pathslash);
    free(path);
    return obj;
}

value_t builtin_command_name(value_t *args, uint32_t nargs)
{
    char *path;
    char *p;

    (void)args;
    argcount("command-name", nargs, 0);
    if (!script_file) {
        return FL_F;
    }
    path = strdup(script_file);
    for (p = strchr(path, 0); p > path; p--) {
        if (p[-1] == '/')
            break;
    }
    return string_from_cstr(p);
}

value_t builtin_command_args(value_t *args, uint32_t nargs)
{
    value_t v;
    int i;

    (void)args;
    argcount("command-args", nargs, 0);
    if (command_line_offset < 1) {
        return FL_NIL;
    }
    v = os_command_line;
    for (i = 0; i < command_line_offset + 1; i++) {
        v = cdr(v);
    }
    return v;
}

value_t builtin_command_line(value_t *args, uint32_t nargs)
{
    value_t cmdname, cmdargs;

    (void)args;
    argcount("command-line", nargs, 0);
    cmdname = builtin_command_name(0, 0);
    cmdargs = builtin_command_args(0, 0);
    if (cmdname == FL_F) {
        cmdname = string_from_cstr("");
    }
    return fl_cons(cmdname, cmdargs);
}

//

value_t builtin_os_current_directory_as_bytevector(value_t *args,
                                                   uint32_t nargs)
{
    (void)args;
    argcount("os-current-directory-as-bytevector", nargs, 0);
    return string_from_cstr(getcwd(NULL, 0));
}

value_t builtin_os_environment_variable_as_bytevector(value_t *args,
                                                      uint32_t nargs)
{
    argcount("os-environment-variable-as-bytevector", nargs, 1);
    char *name = tostring(args[0], "os-environment-variable-as-bytevector");
    const char *value = getenv(name);
    return value ? string_from_cstr(value) : FL_F;
}

value_t builtin_os_environment_variables_as_bytevectors(value_t *args,
                                                        uint32_t nargs)
{
    char **varp;
    const char *var;
    const char *sep;
    value_t head, tail, newtail;

    (void)args;
    argcount("os-environment-variables-as-bytevectors", nargs, 0);
    head = tail = newtail = FL_NIL;
    fl_gc_handle(&head);
    fl_gc_handle(&tail);
    fl_gc_handle(&newtail);
    head = tail = fl_cons(FL_NIL, FL_NIL);
    for (varp = environ; (var = *varp); varp++) {
        if ((sep = strchr(var, '='))) {
            newtail = fl_cons(string_from_cstrn(var, sep - var),
                              string_from_cstr(sep + 1));
        } else {
            newtail = fl_cons(string_from_cstr(var), FL_NIL);
        }
        newtail = fl_cons(newtail, FL_NIL);
        cdr_(tail) = newtail;
        tail = newtail;
    }
    fl_free_gc_handles(3);
    return cdr_(head);
}

value_t builtin_os_command_line_as_bytevector(value_t *args, uint32_t nargs)
{
    (void)args;
    argcount("os-command-line-as-bytevector", nargs, 0);
    return FL_F;
}

value_t builtin_os_command_line_as_bytevectors(value_t *args, uint32_t nargs)
{
    (void)args;
    argcount("os-command-line-as-bytevectors", nargs, 0);
    return os_command_line;
}

value_t builtin_os_executable_file_as_bytevector(value_t *args,
                                                 uint32_t nargs)
{
    (void)args;
    argcount("os-executable-file-as-bytevector", nargs, 0);
    char buf[512];
    char *exe = get_exename(buf, sizeof(buf));
    return exe ? string_from_cstr(exe) : FL_F;
}