#pragma once

#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef _MSC_VER
// For __popcnt
#include <intrin.h>
#endif

#include "krml/internal/target.h"
#include "krml/lowstar_endianness.h"

// C++ HELPERS

#if defined(__cplusplus)

#ifndef KRML_HOST_EPRINTF
#define KRML_HOST_EPRINTF(...) fprintf(stderr, __VA_ARGS__)
#endif

#include <utility>

#ifndef __cpp_lib_type_identity
template <class T>
struct type_identity {
    using type = T
};

template <class T>
using type_identity_t = typename type_identity<T>::type;
#else
using std::type_identity_t;
#endif

#define KRML_UNION_CONSTRUCTOR(T)                              \
    template <typename V>                                      \
    constexpr T(int t, V U::*m, type_identity_t<V> v) : tag(t) \
    {                                                          \
        val.*m = std::move(v);                                 \
    }                                                          \
    T() = default;

#endif

// GENERAL-PURPOSE STUFF

#define LowStar_Ignore_ignore(e, t, _ret_t) ((void)e)

#define EURYDICE_ASSERT(test, msg)                                                  \
    do {                                                                            \
        if (!(test)) {                                                              \
            fprintf(stderr, "assertion \"%s\" failed: file \"%s\", line %d\n", msg, \
                    __FILE__, __LINE__);                                            \
            exit(255);                                                              \
        }                                                                           \
    } while (0)

// SLICES, ARRAYS, ETC.

// We represent a slice as a pair of an (untyped) pointer, along with the length
// of the slice, i.e. the number of elements in the slice (this is NOT the
// number of bytes). This design choice has two important consequences.
// - if you need to use `ptr`, you MUST cast it to a proper type *before*
//   performing pointer arithmetic on it (remember that C desugars pointer
//   arithmetic based on the type of the address)
// - if you need to use `len` for a C style function (e.g. memcpy, memcmp), you
//   need to multiply it by sizeof t, where t is the type of the elements.
//
// Empty slices have `len == 0` and `ptr` always needs to be a valid pointer
// that is not NULL (otherwise the construction in EURYDICE_SLICE computes `NULL
// + start`).
typedef struct {
    void *ptr;
    size_t len;
} Eurydice_slice;

#if defined(__cplusplus)
#define KRML_CLITERAL(type) type
#else
#define KRML_CLITERAL(type) (type)
#endif

#if defined(__cplusplus) && defined(__cpp_designated_initializers) || \
    !(defined(__cplusplus))
#define EURYDICE_CFIELD(X) X
#else
#define EURYDICE_CFIELD(X)
#endif

// Helper macro to create a slice out of a pointer x, a start index in x
// (included), and an end index in x (excluded). The argument x must be suitably
// cast to something that can decay (see remark above about how pointer
// arithmetic works in C), meaning either pointer or array type.
#define EURYDICE_SLICE(x, start, end) \
    (KRML_CLITERAL(Eurydice_slice){ (void *)(x + start), end - start })

// Slice length
#define EURYDICE_SLICE_LEN(s, _) (s).len
#define Eurydice_slice_len(s, _) (s).len

// This macro is a pain because in case the dereferenced element type is an
// array, you cannot simply write `t x` as it would yield `int[4] x` instead,
// which is NOT correct C syntax, so we add a dedicated phase in Eurydice that
// adds an extra argument to this macro at the last minute so that we have the
// correct type of *pointers* to elements.
#define Eurydice_slice_index(s, i, t, t_ptr_t) (((t_ptr_t)s.ptr)[i])

// The following functions get sub slices from a slice.

#define Eurydice_slice_subslice(s, r, t, _0, _1) \
    EURYDICE_SLICE((t *)s.ptr, r.start, r.end)

// Variant for when the start and end indices are statically known (i.e., the
// range argument `r` is a literal).
#define Eurydice_slice_subslice2(s, start, end, t) \
    EURYDICE_SLICE((t *)s.ptr, (start), (end))

#define Eurydice_slice_subslice_to(s, subslice_end_pos, t, _0, _1) \
    EURYDICE_SLICE((t *)s.ptr, 0, subslice_end_pos)

#define Eurydice_slice_subslice_from(s, subslice_start_pos, t, _0, _1) \
    EURYDICE_SLICE((t *)s.ptr, subslice_start_pos, s.len)

#define Eurydice_array_to_slice(end, x, t) \
    EURYDICE_SLICE(x, 0,                   \
                   end) /* x is already at an array type, no need for cast */
#define Eurydice_array_to_subslice(_arraylen, x, r, t, _0, _1) \
    EURYDICE_SLICE((t *)x, r.start, r.end)

// Same as above, variant for when start and end are statically known
#define Eurydice_array_to_subslice2(x, start, end, t) \
    EURYDICE_SLICE((t *)x, (start), (end))

// Same as above, variant for when start and end are statically known
#define Eurydice_array_to_subslice3(x, start, end, t_ptr) \
    EURYDICE_SLICE((t_ptr)x, (start), (end))

#define Eurydice_array_repeat(dst, len, init, t) \
    ERROR "should've been desugared"

// The following functions convert an array into a slice.

#define Eurydice_array_to_subslice_to(_size, x, r, t, _range_t, _0) \
    EURYDICE_SLICE((t *)x, 0, r)
#define Eurydice_array_to_subslice_from(size, x, r, t, _range_t, _0) \
    EURYDICE_SLICE((t *)x, r, size)

// Copy a slice with memcopy
#define Eurydice_slice_copy(dst, src, t) \
    memcpy(dst.ptr, src.ptr, dst.len * sizeof(t))

#define core_array___Array_T__N___as_slice(len_, ptr_, t, _ret_t) \
    KRML_CLITERAL(Eurydice_slice) { ptr_, len_ }

#define core_array__core__clone__Clone_for__Array_T__N___clone( \
    len, src, dst, elem_type, _ret_t)                           \
    (memcpy(dst, src, len * sizeof(elem_type)))
#define TryFromSliceError uint8_t
#define core_array_TryFromSliceError uint8_t

#define Eurydice_array_eq(sz, a1, a2, t) (memcmp(a1, a2, sz * sizeof(t)) == 0)

// core::cmp::PartialEq<&0 (@Slice<U>)> for @Array<T, N>
#define Eurydice_array_eq_slice(sz, a1, s2, t, _) \
    (memcmp(a1, (s2)->ptr, sz * sizeof(t)) == 0)

#define core_array_equality___core__cmp__PartialEq__Array_U__N___for__Array_T__N____eq( \
    sz, a1, a2, t, _, _ret_t)                                                           \
    Eurydice_array_eq(sz, a1, a2, t, _)
#define core_array_equality___core__cmp__PartialEq__0___Slice_U____for__Array_T__N___3__eq( \
    sz, a1, a2, t, _, _ret_t)                                                               \
    Eurydice_array_eq(sz, a1, ((a2)->ptr), t, _)

#define Eurydice_slice_split_at(slice, mid, element_type, ret_t)              \
    KRML_CLITERAL(ret_t)                                                      \
    {                                                                         \
        EURYDICE_CFIELD(.fst =)                                               \
        EURYDICE_SLICE((element_type *)(slice).ptr, 0, mid),                  \
            EURYDICE_CFIELD(.snd =)                                           \
                EURYDICE_SLICE((element_type *)(slice).ptr, mid, (slice).len) \
    }

#define Eurydice_slice_split_at_mut(slice, mid, element_type, ret_t)       \
    KRML_CLITERAL(ret_t)                                                   \
    {                                                                      \
        EURYDICE_CFIELD(.fst =)                                            \
        KRML_CLITERAL(Eurydice_slice){ EURYDICE_CFIELD(.ptr =)(slice.ptr), \
                                       EURYDICE_CFIELD(.len =) mid },      \
            EURYDICE_CFIELD(.snd =) KRML_CLITERAL(Eurydice_slice)          \
        {                                                                  \
            EURYDICE_CFIELD(.ptr =)                                        \
            ((char *)slice.ptr + mid * sizeof(element_type)),              \
                EURYDICE_CFIELD(.len =)(slice.len - mid)                   \
        }                                                                  \
    }

// Conversion of slice to an array, rewritten (by Eurydice) to name the
// destination array, since arrays are not values in C.
// N.B.: see note in karamel/lib/Inlining.ml if you change this.
#define Eurydice_slice_to_array2(dst, src, _0, t_arr, _1)                   \
    Eurydice_slice_to_array3(&(dst)->tag, (char *)&(dst)->val.case_Ok, src, \
                             sizeof(t_arr))

static inline void
Eurydice_slice_to_array3(uint8_t *dst_tag, char *dst_ok,
                         Eurydice_slice src, size_t sz)
{
    *dst_tag = 0;
    memcpy(dst_ok, src.ptr, sz);
}

// SUPPORT FOR DSTs (Dynamically-Sized Types)

// A DST is a fat pointer that keeps tracks of the size of it flexible array
// member. Slices are a specific case of DSTs, where [T; N] implements
// Unsize<[T]>, meaning an array of statically known size can be converted to a
// fat pointer, i.e. a slice.
//
// Unlike slices, DSTs have a built-in definition that gets monomorphized, of
// the form:
//
// typedef struct {
//   T *ptr;
//   size_t len; // number of elements
// } Eurydice_dst;
//
// Furthermore, T = T0<[U0]> where `struct T0<U: ?Sized>`, where the `U` is the
// last field. This means that there are two monomorphizations of T0 in the
// program. One is `T0<[V; N]>`
// -- this is directly converted to a Eurydice_dst via suitable codegen (no
// macro). The other is `T = T0<[U]>`, where `[U]` gets emitted to
// `Eurydice_derefed_slice`, a type that only appears in that precise situation
// and is thus defined to give rise to a flexible array member.

typedef char Eurydice_derefed_slice[];

#define Eurydice_slice_of_dst(fam_ptr, len_, t, _) \
    ((Eurydice_slice){ .ptr = (void *)(fam_ptr), .len = len_ })

#define Eurydice_slice_of_boxed_array(ptr_, len_, t, _) \
    ((Eurydice_slice){ .ptr = (void *)(ptr_), .len = len_ })

// CORE STUFF (conversions, endianness, ...)

// We slap extern "C" on declarations that intend to implement a prototype
// generated by Eurydice, because Eurydice prototypes are always emitted within
// an extern "C" block, UNLESS you use -fcxx17-compat, in which case, you must
// pass -DKRML_CXX17_COMPAT="" to your C++ compiler.
#if defined(__cplusplus) && !defined(KRML_CXX17_COMPAT)
extern "C" {
#endif

static inline void
core_num__u32__to_be_bytes(uint32_t src, uint8_t dst[4])
{
    // TODO: why not store32_be?
    uint32_t x = htobe32(src);
    memcpy(dst, &x, 4);
}

static inline void
core_num__u32__to_le_bytes(uint32_t src, uint8_t dst[4])
{
    store32_le(dst, src);
}

static inline uint32_t
core_num__u32__from_le_bytes(uint8_t buf[4])
{
    return load32_le(buf);
}

static inline void
core_num__u64__to_le_bytes(uint64_t v, uint8_t buf[8])
{
    store64_le(buf, v);
}

static inline uint64_t
core_num__u64__from_le_bytes(uint8_t buf[8])
{
    return load64_le(buf);
}

static inline int64_t
core_convert_num___core__convert__From_i32__for_i64___from(int32_t x)
{
    return x;
}

static inline uint64_t
core_convert_num___core__convert__From_u8__for_u64___from(uint8_t x)
{
    return x;
}

static inline uint64_t
core_convert_num___core__convert__From_u16__for_u64___from(uint16_t x)
{
    return x;
}

static inline size_t
core_convert_num___core__convert__From_u16__for_usize___from(uint16_t x)
{
    return x;
}

static inline uint32_t
core_num__u8__count_ones(uint8_t x0)
{
#ifdef _MSC_VER
    return __popcnt(x0);
#else
    return __builtin_popcount(x0);
#endif
}

static inline uint32_t
core_num__i32__count_ones(int32_t x0)
{
#ifdef _MSC_VER
    return __popcnt(x0);
#else
    return __builtin_popcount(x0);
#endif
}

static inline size_t
core_cmp_impls___core__cmp__Ord_for_usize___min(size_t a,
                                                size_t b)
{
    if (a <= b)
        return a;
    else
        return b;
}

// unsigned overflow wraparound semantics in C
static inline uint16_t
core_num__u16__wrapping_add(uint16_t x, uint16_t y)
{
    return x + y;
}
static inline uint8_t
core_num__u8__wrapping_sub(uint8_t x, uint8_t y)
{
    return x - y;
}
static inline uint64_t
core_num__u64__rotate_left(uint64_t x0, uint32_t x1)
{
    return (x0 << x1 | x0 >> (64 - x1));
}

static inline void
core_ops_arith__i32__add_assign(int32_t *x0, int32_t *x1)
{
    *x0 = *x0 + *x1;
}

static inline uint8_t
Eurydice_bitand_pv_u8(uint8_t *p, uint8_t v)
{
    return (*p) & v;
}
static inline uint8_t
Eurydice_shr_pv_u8(uint8_t *p, int32_t v)
{
    return (*p) >> v;
}
static inline uint32_t
Eurydice_min_u32(uint32_t x, uint32_t y)
{
    return x < y ? x : y;
}

static inline uint8_t
core_ops_bit___core__ops__bit__BitAnd_u8__u8__for___a__u8___46__bitand(
    uint8_t *x0, uint8_t x1)
{
    return Eurydice_bitand_pv_u8(x0, x1);
}

static inline uint8_t
core_ops_bit___core__ops__bit__Shr_i32__u8__for___a__u8___792__shr(uint8_t *x0,
                                                                   int32_t x1)
{
    return Eurydice_shr_pv_u8(x0, x1);
}

#define core_num_nonzero_private_NonZeroUsizeInner size_t
static inline core_num_nonzero_private_NonZeroUsizeInner
core_num_nonzero_private___core__clone__Clone_for_core__num__nonzero__private__NonZeroUsizeInner__26__clone(
    core_num_nonzero_private_NonZeroUsizeInner *x0)
{
    return *x0;
}

#if defined(__cplusplus) && !defined(KRML_CXX17_COMPAT)
}
#endif

// ITERATORS

#define Eurydice_range_iter_next(iter_ptr, t, ret_t)          \
    (((iter_ptr)->start >= (iter_ptr)->end)                   \
         ? (KRML_CLITERAL(ret_t){ EURYDICE_CFIELD(.tag =) 0,  \
                                  EURYDICE_CFIELD(.f0 =) 0 }) \
         : (KRML_CLITERAL(ret_t){ EURYDICE_CFIELD(.tag =) 1,  \
                                  EURYDICE_CFIELD(.f0 =)(iter_ptr)->start++ }))

#define core_iter_range___core__iter__traits__iterator__Iterator_A__for_core__ops__range__Range_A__TraitClause_0___6__next \
    Eurydice_range_iter_next

// See note in karamel/lib/Inlining.ml if you change this
#define Eurydice_into_iter(x, t, _ret_t, _) (x)
#define core_iter_traits_collect___core__iter__traits__collect__IntoIterator_Clause1_Item__I__for_I__1__into_iter \
    Eurydice_into_iter

typedef struct {
    Eurydice_slice slice;
    size_t chunk_size;
} Eurydice_chunks;

// Can't use macros Eurydice_slice_subslice_{to,from} because they require a
// type, and this static inline function cannot receive a type as an argument.
// Instead, we receive the element size and use it to peform manual offset
// computations rather than going through the macros.
static inline Eurydice_slice
chunk_next(Eurydice_chunks *chunks,
           size_t element_size)
{
    size_t chunk_size = chunks->slice.len >= chunks->chunk_size
                            ? chunks->chunk_size
                            : chunks->slice.len;
    Eurydice_slice curr_chunk;
    curr_chunk.ptr = chunks->slice.ptr;
    curr_chunk.len = chunk_size;
    chunks->slice.ptr = (char *)(chunks->slice.ptr) + chunk_size * element_size;
    chunks->slice.len = chunks->slice.len - chunk_size;
    return curr_chunk;
}

// using it anyway??
#define Eurydice_slice_subslice3(s, start, end, t_ptr) \
    EURYDICE_SLICE((t_ptr)s.ptr, (start), (end))

#define core_slice___Slice_T___chunks(slice_, sz_, t, _ret_t) \
    ((Eurydice_chunks){ .slice = slice_, .chunk_size = sz_ })
#define core_slice___Slice_T___chunks_exact(slice_, sz_, t, _ret_t)             \
    ((Eurydice_chunks){                                                         \
        .slice = { .ptr = slice_.ptr, .len = slice_.len - (slice_.len % sz_) }, \
        .chunk_size = sz_ })
#define core_slice_iter_Chunks Eurydice_chunks
#define core_slice_iter_ChunksExact Eurydice_chunks
#define Eurydice_chunks_next(iter, t, ret_t)                         \
    (((iter)->slice.len == 0) ? ((ret_t){ .tag = core_option_None }) \
                              : ((ret_t){ .tag = core_option_Some,   \
                                          .f0 = chunk_next(iter, sizeof(t)) }))
#define core_slice_iter___core__iter__traits__iterator__Iterator_for_core__slice__iter__Chunks__a__T___70__next \
    Eurydice_chunks_next
// This name changed on 20240627
#define core_slice_iter___core__iter__traits__iterator__Iterator_for_core__slice__iter__Chunks__a__T___71__next \
    Eurydice_chunks_next
#define core_slice_iter__core__slice__iter__ChunksExact__a__T__89__next( \
    iter, t, _ret_t)                                                     \
    core_slice_iter__core__slice__iter__Chunks__a__T__70__next(iter, t)

typedef struct {
    Eurydice_slice s;
    size_t index;
} Eurydice_slice_iterator;

#define core_slice___Slice_T___iter(x, t, _ret_t) \
    ((Eurydice_slice_iterator){ .s = x, .index = 0 })
#define core_slice_iter_Iter Eurydice_slice_iterator
#define core_slice_iter__core__slice__iter__Iter__a__T__181__next(iter, t, \
                                                                  ret_t)   \
    (((iter)->index == (iter)->s.len)                                      \
         ? (KRML_CLITERAL(ret_t){ .tag = core_option_None })               \
         : (KRML_CLITERAL(ret_t){                                          \
               .tag = core_option_Some,                                    \
               .f0 = ((iter)->index++,                                     \
                      &((t *)((iter)->s.ptr))[(iter)->index - 1]) }))
#define core_option__core__option__Option_T__TraitClause_0___is_some(X, _0, \
                                                                     _1)    \
    ((X)->tag == 1)
// STRINGS

typedef const char *Prims_string;

// MISC (UNTESTED)

typedef void *core_fmt_Formatter;
typedef void *core_fmt_Arguments;
typedef void *core_fmt_rt_Argument;
#define core_fmt_rt__core__fmt__rt__Argument__a__1__new_display(x1, x2, x3, \
                                                                x4)         \
    NULL

// BOXES

// Crimes.
static inline char *
malloc_and_init(size_t sz, char *init)
{
    char *ptr = (char *)malloc(sz);
    memcpy(ptr, init, sz);
    return ptr;
}

#define Eurydice_box_new(init, t, t_dst) \
    ((t_dst)(malloc_and_init(sizeof(t), (char *)(&init))))

#define Eurydice_box_new_array(len, ptr, t, t_dst) \
    ((t_dst)(malloc_and_init(len * sizeof(t), (char *)(ptr))))

// VECTORS (ANCIENT, POSSIBLY UNTESTED)

/* For now these are passed by value -- three words. We could conceivably change
 * the representation to heap-allocate this struct and only pass around the
 * pointer (one word). */
typedef struct {
    void *ptr;
    size_t len;        /* the number of elements */
    size_t alloc_size; /* the size of the allocation, in number of BYTES */
} Eurydice_vec_s, *Eurydice_vec;

/* Here, we set everything to zero rather than use a non-standard GCC
 * statement-expression -- this suitably initializes ptr to NULL and len and
 * size to 0. */
#define EURYDICE_VEC_NEW(_) calloc(1, sizeof(Eurydice_vec_s))
#define EURYDICE_VEC_PUSH(v, x, t)                                              \
    do {                                                                        \
        /* Grow the vector if capacity has been reached. */                     \
        if (v->len == v->alloc_size / sizeof(t)) {                              \
            /* Assuming that this does not exceed SIZE_MAX, because code proven \
             * correct by Aeneas. Would this even happen in practice? */        \
            size_t new_size;                                                    \
            if (v->alloc_size == 0)                                             \
                new_size = 8 * sizeof(t);                                       \
            else if (v->alloc_size <= SIZE_MAX / 2)                             \
                /* TODO: discuss growth policy */                               \
                new_size = 2 * v->alloc_size;                                   \
            else                                                                \
                new_size = (SIZE_MAX / sizeof(t)) * sizeof(t);                  \
            v->ptr = realloc(v->ptr, new_size);                                 \
            v->alloc_size = new_size;                                           \
        }                                                                       \
        ((t *)v->ptr)[v->len] = x;                                              \
        v->len++;                                                               \
    } while (0)

#define EURYDICE_VEC_DROP(v, t) \
    do {                        \
        free(v->ptr);           \
        free(v);                \
    } while (0)

#define EURYDICE_VEC_INDEX(v, i, t) &((t *)v->ptr)[i]
#define EURYDICE_VEC_LEN(v, t) (v)->len

/* TODO: remove GCC-isms */

#define EURYDICE_REPLACE(ptr, new_v, t) \
    ({                                  \
        t old_v = *ptr;                 \
        *ptr = new_v;                   \
        old_v;                          \
    })