/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
#include <tvm/ffi/function.h>
#include <tvm/ffi/reflection/registry.h>
#include <tvm/ir/module.h>
#include <tvm/runtime/logging.h>
#include <tvm/script/ir_builder/ir/ir.h>

#include "./utils.h"

namespace tvm {
namespace script {
namespace ir_builder {
namespace ir {

IRModuleFrame IRModule() {
  ffi::ObjectPtr<IRModuleFrameNode> n = ffi::make_object<IRModuleFrameNode>();
  n->global_var_map.clear();
  n->functions.clear();
  return IRModuleFrame(n);
}

// DeclFunction lives at the IR layer because an IRModule may host
// heterogeneous function kinds (e.g. relax::Function, tirx::PrimFunc).
// To derive the GlobalVar's ty without coupling the IR layer to
// any specific dialect, dispatch is keyed by the function's type-key:
// each dialect registers its own handler that maps a function of that
// type to the appropriate ty.
inline ffi::Optional<Type> GetGlobalVarType(const BaseFunc& func) {
  if (!func->ty.IsMissing()) {
    return func->ty;
  }
  // Registry: "script.ir_builder.decl_function.<type-key>" — per-function-kind
  // handler that derives the GlobalVar ty from the function signature.
  // Grep hint: grep -rn 'script.ir_builder.decl_function.' src/
  const std::string key = "script.ir_builder.decl_function." + func->GetTypeKey();
  if (auto fn = tvm::ffi::Function::GetGlobal(key)) {
    ffi::Optional<ffi::ObjectRef> result = (*fn)(func).cast<ffi::Optional<ffi::ObjectRef>>();
    if (result.has_value()) {
      return result.value().as_or_throw<Type>();
    }
  }
  return std::nullopt;
}

GlobalVar DeclFunction(const ffi::String& func_name, const BaseFunc& func_signature) {
  IRModuleFrame frame = FindModuleFrame();
  TVM_FFI_CHECK(!frame->global_var_map.count(func_name), ValueError)
      << "function " << func_name << " already exists";

  GlobalVar gv = GlobalVar(func_name);
  if (auto ty = GetGlobalVarType(func_signature)) {
    gv->ty = ty.value();
  } else {
    TVM_FFI_THROW(InternalError) << "Unsupported function type: " << func_signature->GetTypeKey();
  }
  TVM_FFI_CHECK(frame->functions.find(gv) == frame->functions.end(), ValueError)
      << "function " << func_name << " has already been defined.";
  frame->global_var_map.Set(func_name, gv);
  frame->functions.Set(gv, func_signature);
  return gv;
}

void DefFunction(const ffi::String& func_name, const BaseFunc& func) {
  IRModuleFrame frame = FindModuleFrame();
  auto it = frame->global_var_map.find(func_name);
  TVM_FFI_CHECK(it != frame->global_var_map.end(), ValueError)
      << "function " << func_name << " does not exist, please declare it first.";
  const GlobalVar& gv = (*it).second;
  frame->functions.Set(gv, func);
  if (auto ty = GetGlobalVarType(func)) {
    gv->ty = ty.value();
  } else {
    TVM_FFI_THROW(InternalError) << "Unsupported function type: " << func->GetTypeKey();
  }
}

void ModuleAttrs(ffi::Map<ffi::String, Any> attrs, bool allow_overwrite) {
  if (IRBuilder::IsInScope()) {
    // TODO(hongyi): add comments to explain why we need to check if the module frame is in scope
    IRModuleFrame frame = FindModuleFrame("I.ModuleAttr");
    if (!allow_overwrite && !frame->attrs.empty()) {
      TVM_FFI_THROW(ValueError) << "Duplicate module attrs, previous one is:\n" << frame->attrs;
    }
    frame->attrs = attrs;
  }
}

ffi::Optional<ffi::ObjectRef> ModuleGetAttr(const ffi::String& key) {
  if (IRBuilder::IsInScope()) {
    IRModuleFrame frame = FindModuleFrame();
    if (frame->attrs.find(key) != frame->attrs.end()) {
      return frame->attrs[key].cast<ffi::ObjectRef>();
    }
  }
  return std::nullopt;
}

void ModuleSetAttr(const ffi::String& key, const ffi::Optional<ffi::ObjectRef>& value,
                   bool allow_override) {
  if (IRBuilder::IsInScope()) {
    IRModuleFrame frame = FindModuleFrame();
    if (!allow_override && frame->attrs.find(key) != frame->attrs.end() && value.has_value()) {
      TVM_FFI_THROW(ValueError) << "Duplicate module attr " << key;
    }
    if (value.has_value()) {
      frame->attrs.Set(key, value.value());
    } else {
      frame->attrs.erase(key);
    }
  } else {
    TVM_FFI_THROW(ValueError) << "Currently in in the scope of a module.";
  }
}

void ModuleGlobalInfos(ffi::Map<ffi::String, ffi::Array<GlobalInfo>> global_infos) {
  if (IRBuilder::IsInScope()) {
    IRModuleFrame frame = FindModuleFrame("I.ModuleGlobalInfos");
    if (!frame->global_infos.empty()) {
      TVM_FFI_THROW(ValueError) << "Duplicate module global_infos, previous one is:\n"
                                << frame->global_infos;
    }
    frame->global_infos = global_infos;
  }
}

VDevice LookupVDevice(ffi::String target_kind, int device_index) {
  if (IRBuilder::IsInScope()) {
    IRModuleFrame frame = FindModuleFrame();
    if (frame->global_infos.empty()) {
      TVM_FFI_THROW(ValueError) << "The GlobalInfos in the IRModule is not defined.";
    }
    ffi::Array<GlobalInfo> vdevices = frame->global_infos["vdevice"];
    if (vdevices.empty() || device_index < 0 ||
        static_cast<size_t>(device_index) >= vdevices.size()) {
      TVM_FFI_THROW(ValueError) << "The target VDevice in the GlobalInfos was not found.";
    }
    if (target_kind == "vdevice") {
      return vdevices[device_index].as_or_throw<VDevice>();
    }
    int count = 0;
    for (auto vdevice : vdevices) {
      auto vdev = vdevice.as_or_throw<VDevice>();
      if (vdev->target->kind->name == target_kind) {
        if (count == device_index) {
          return vdev;
        }
        count++;
      }
    }
  }
  LOG(WARNING) << "The annotated device was not found, please check your vdevice list.";
  return VDevice();
}

bool LookupName(const ffi::String& name) {
  if (IRBuilder::IsInScope()) {
    IRModuleFrame frame = FindModuleFrame();
    return frame->global_var_map.find(name) != frame->global_var_map.end();
  }
  return false;
}

TVM_FFI_STATIC_INIT_BLOCK() {
  namespace refl = tvm::ffi::reflection;
  refl::GlobalDef()
      .def("script.ir_builder.ir.IRModule", IRModule)
      .def("script.ir_builder.ir.DeclFunction", DeclFunction)
      .def("script.ir_builder.ir.DefFunction", DefFunction)
      .def("script.ir_builder.ir.ModuleAttrs", ModuleAttrs)
      .def("script.ir_builder.ir.ModuleGetAttr", ModuleGetAttr)
      .def("script.ir_builder.ir.ModuleSetAttr", ModuleSetAttr)
      .def("script.ir_builder.ir.ModuleGlobalInfos", ModuleGlobalInfos)
      .def("script.ir_builder.ir.LookupVDevice", LookupVDevice)
      .def("script.ir_builder.ir.LookupName", LookupName);
}

}  // namespace ir
}  // namespace ir_builder
}  // namespace script
}  // namespace tvm
