#pragma once
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include <cstdint>
#include <functional>
#include <utility>
#include <string>

namespace cps {

class ExceptionHandler;

class RuntimeCheck {
    llvm::Module &TheModule;
    llvm::LLVMContext &TheContext;
    llvm::IRBuilder<> &Builder;

    llvm::FunctionCallee FprintfFunc;
    llvm::FunctionCallee StderrFunc;   // Windows: __acrt_iob_func(2)
    llvm::GlobalVariable *StderrVar;   // elsewhere: the C library's stderr
    ExceptionHandler &Exceptions;
    std::function<bool(int)> LibraryLookup;
    llvm::GlobalVariable *UserLine;
    llvm::Value *DivZeroMsg;
    llvm::Value *OutOfBoundsMsg;
    llvm::Value *EnumRangeMsg;
    llvm::Value *NullDerefMsg;
    llvm::Value *ArrayArgBoundsMsg;

    void setupExternalFunctions();
    void emitCheck(llvm::Value *Condition, llvm::Value *Msg, int Line);

public:
    RuntimeCheck(llvm::Module &M, llvm::LLVMContext &C, llvm::IRBuilder<> &B,
                 ExceptionHandler &EH);

    void setLibraryLookup(std::function<bool(int)> Lookup) { LibraryLookup = std::move(Lookup); }
    llvm::Value *lineValue(int Line);
    void setUserLine(int Line);

    // Format a runtime diagnostic (printf-style) and write it to stderr.
    void emitStderr(llvm::Value *Msg, llvm::ArrayRef<llvm::Value *> FmtArgs = {});

    void emitDivZeroCheck(llvm::Value *Divisor, int Line);
    void emitIndexCheck(llvm::Value *Index, llvm::Value *Lower, llvm::Value *Upper, int Line);

    // Enum +/- INTEGER results must stay inside the enum's value range.
    void emitEnumRangeCheck(llvm::Value *Ordinal, uint64_t ValueCount,
                            const std::string &TypeName, int Line);

    // Dereferencing an unset (null) pointer throws instead of segfaulting.
    void emitNullDerefCheck(llvm::Value *Ptr, int Line);

    // A bounded array parameter is a contract: the argument's runtime bounds
    // must equal the declared ones.
    void emitArrayArgBoundsCheck(llvm::Value *ActualLower, llvm::Value *ActualUpper,
                                 int64_t DeclaredLower, int64_t DeclaredUpper, int Line);

    // Print the diagnostic to stderr, then throw an anonymous exception on failure.
    // Runtime-computed variant: FmtArgs are the printf varargs after Msg
    // (e.g. {i32 line, ptr filename}). Needed when the failure site is inside
    // a synthesized helper function, where the line number is an argument
    // rather than a compile-time constant.
    void emitCheck(llvm::Value *Condition, llvm::Value *Msg,
                   llvm::ArrayRef<llvm::Value *> FmtArgs);
};

}