#include "attr-set.hh"
#include "config.hh"
#include "eval.hh"
#include "gc/gc.h"
#include "globals.hh"
#include "value.hh"

#include "nix_api_expr.h"
#include "nix_api_expr_internal.h"
#include "nix_api_util.h"
#include "nix_api_util_internal.h"
#include "nix_api_value.h"

#ifdef HAVE_BOEHMGC
#define GC_INCLUDE_NEW 1
#include "gc_cpp.h"
#endif

// Helper function to throw an exception if value is null
static const nix::Value &check_value_not_null(const Value *value) {
  if (!value) {
    throw std::runtime_error("Value is null");
  }
  return *((const nix::Value *)value);
}

static nix::Value &check_value_not_null(Value *value) {
  if (!value) {
    throw std::runtime_error("Value is null");
  }
  return *((nix::Value *)value);
}

PrimOp *nix_alloc_primop(nix_c_context *context, PrimOpFun fun, int arity,
                         const char *name, const char **args, const char *doc,
                         GCRef *ref) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto fun2 = (nix::PrimOpFun)fun;
    auto p = new
#ifdef HAVE_BOEHMGC
        (GC)
#endif
            nix::PrimOp{.name = name,
                        .args = {},
                        .arity = (size_t)arity,
                        .doc = doc,
                        .fun = fun2};
    if (args)
      for (size_t i = 0; args[i]; i++)
        p->args.emplace_back(*args);
    if (ref)
      ref->ptr = p;
    return (PrimOp *)p;
  }
  NIXC_CATCH_ERRS_NULL
}

Value *nix_alloc_value(nix_c_context *context, State *state, GCRef *ref) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    Value *res = state->state.allocValue();
    if (ref)
      ref->ptr = res;
    return res;
  }
  NIXC_CATCH_ERRS_NULL
}

ValueType nix_get_type(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    using namespace nix;
    switch (v.type()) {
    case nThunk:
      return NIX_TYPE_THUNK;
    case nInt:
      return NIX_TYPE_INT;
    case nFloat:
      return NIX_TYPE_FLOAT;
    case nBool:
      return NIX_TYPE_BOOL;
    case nString:
      return NIX_TYPE_STRING;
    case nPath:
      return NIX_TYPE_PATH;
    case nNull:
      return NIX_TYPE_NULL;
    case nAttrs:
      return NIX_TYPE_ATTRS;
    case nList:
      return NIX_TYPE_LIST;
    case nFunction:
      return NIX_TYPE_FUNCTION;
    case nExternal:
      return NIX_TYPE_EXTERNAL;
    }
    return NIX_TYPE_NULL;
  }
  NIXC_CATCH_ERRS_RES(NIX_TYPE_NULL);
}

const char *nix_get_typename(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    auto s = nix::showType(v);
    return strdup(s.c_str());
  }
  NIXC_CATCH_ERRS_NULL
}

bool nix_get_bool(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nBool);
    return v.boolean;
  }
  NIXC_CATCH_ERRS_RES(false);
}

const char *nix_get_string(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nString);
    return v.string.s;
  }
  NIXC_CATCH_ERRS_NULL
}

const char *nix_get_path_string(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nPath);
    return v._path;
  }
  NIXC_CATCH_ERRS_NULL
}

unsigned int nix_get_list_size(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nList);
    return v.listSize();
  }
  NIXC_CATCH_ERRS_RES(0);
}

unsigned int nix_get_attrs_size(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nAttrs);
    return v.attrs->size();
  }
  NIXC_CATCH_ERRS_RES(0);
}

double nix_get_float(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nFloat);
    return v.fpoint;
  }
  NIXC_CATCH_ERRS_RES(NAN);
}

int64_t nix_get_int(nix_c_context *context, const Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nInt);
    return v.integer;
  }
  NIXC_CATCH_ERRS_RES(0);
}

ExternalValue *nix_get_external(nix_c_context *context, Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nExternal);
    return (ExternalValue *)v.external;
  }
  NIXC_CATCH_ERRS_NULL;
}

Value *nix_get_list_byidx(nix_c_context *context, const Value *value,
                          unsigned int ix, GCRef *ref) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nList);
    return (Value *)v.listElems()[ix];
  }
  NIXC_CATCH_ERRS_NULL
}

Value *nix_get_attr_byname(nix_c_context *context, const Value *value,
                           State *state, const char *name, GCRef *ref) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nAttrs);
    nix::Symbol s = state->state.symbols.create(name);
    auto attr = v.attrs->get(s);
    if (attr) {
      if (ref)
        ref->ptr = attr->value;
      return attr->value;
    }
    nix_set_err_msg(context, NIX_ERR_KEY, "missing attribute");
    return nullptr;
  }
  NIXC_CATCH_ERRS_NULL
}

bool nix_has_attr_byname(nix_c_context *context, const Value *value,
                         State *state, const char *name) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    assert(v.type() == nix::nAttrs);
    nix::Symbol s = state->state.symbols.create(name);
    auto attr = v.attrs->get(s);
    if (attr)
      return true;
    return false;
  }
  NIXC_CATCH_ERRS_RES(false);
}

Value *nix_get_attr_byidx(nix_c_context *context, const Value *value,
                          State *state, unsigned int i, const char **name,
                          GCRef *ref) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    const nix::Attr &a = (*v.attrs)[i];
    *name = ((const std::string &)(state->state.symbols[a.name])).c_str();
    if (ref)
      ref->ptr = a.value;
    return a.value;
  }
  NIXC_CATCH_ERRS_NULL
}

nix_err nix_set_bool(nix_c_context *context, Value *value, bool b) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    v.mkBool(b);
  }
  NIXC_CATCH_ERRS
}

// todo string context
nix_err nix_set_string(nix_c_context *context, Value *value, const char *str) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    v.mkString(std::string_view(str));
  }
  NIXC_CATCH_ERRS
}

nix_err nix_set_path_string(nix_c_context *context, Value *value,
                            const char *str) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    v.mkPath(std::string_view(str));
  }
  NIXC_CATCH_ERRS
}

nix_err nix_set_float(nix_c_context *context, Value *value, double d) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    v.mkFloat(d);
  }
  NIXC_CATCH_ERRS
}

nix_err nix_set_int(nix_c_context *context, Value *value, int64_t i) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    v.mkInt(i);
  }
  NIXC_CATCH_ERRS
}

nix_err nix_set_null(nix_c_context *context, Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    v.mkNull();
  }
  NIXC_CATCH_ERRS
}

nix_err nix_set_external(nix_c_context *context, Value *value,
                         ExternalValue *val) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    auto r = (nix::ExternalValueBase *)val;
    v.mkExternal(r);
  }
  NIXC_CATCH_ERRS
}

nix_err nix_make_list(nix_c_context *context, State *s, Value *value,
                      unsigned int size) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    s->state.mkList(v, size);
  }
  NIXC_CATCH_ERRS
}

nix_err nix_set_list_byidx(nix_c_context *context, Value *value,
                           unsigned int ix, Value *elem) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    // todo: assert that this is a list
    auto &v = check_value_not_null(value);
    auto &e = check_value_not_null(elem);
    v.listElems()[ix] = &e;
  }
  NIXC_CATCH_ERRS
}

nix_err nix_set_primop(nix_c_context *context, Value *value, PrimOp *p) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    v.mkPrimOp((nix::PrimOp *)p);
  }
  NIXC_CATCH_ERRS
}

nix_err nix_copy_value(nix_c_context *context, Value *value, Value *source) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    auto &s = check_value_not_null(source);
    v = s;
  }
  NIXC_CATCH_ERRS
}

nix_err nix_set_thunk(nix_c_context *context, State *s, Value *value,
                      Expr *expr) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    s->state.mkThunk_(v, (nix::Expr *)expr);
  }
  NIXC_CATCH_ERRS
}

typedef std::shared_ptr<nix::BindingsBuilder> BindingsBuilder_Inner;

nix_err nix_make_attrs(nix_c_context *context, Value *value,
                       BindingsBuilder *b) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto &v = check_value_not_null(value);
    nix::BindingsBuilder &builder = **(BindingsBuilder_Inner *)b;
    v.mkAttrs(builder);
  }
  NIXC_CATCH_ERRS
}

BindingsBuilder *nix_make_bindings_builder(nix_c_context *context, State *state,
                                           size_t capacity) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    auto bb = state->state.buildBindings(capacity);
    auto res = new BindingsBuilder_Inner();
    *res = std::allocate_shared<nix::BindingsBuilder>(
        traceable_allocator<nix::BindingsBuilder>(), bb);
    return res;
  }
  NIXC_CATCH_ERRS_NULL
}

nix_err nix_bindings_builder_insert(nix_c_context *context, BindingsBuilder *b,
                                    const char *name, Value *value) {
  if (context)
    context->last_err_code = NIX_OK;
  try {
    nix::BindingsBuilder &builder = **(BindingsBuilder_Inner *)b;
    auto &v = check_value_not_null(value);
    nix::Symbol s = builder.state.symbols.create(name);
    builder.insert(s, &v);
  }
  NIXC_CATCH_ERRS
}

void nix_bindings_builder_unref(BindingsBuilder *bb) {
  delete (BindingsBuilder_Inner *)bb;
}