/* This file is part of the dynarmic project.
 * Copyright (c) 2022 MerryMage
 * SPDX-License-Identifier: 0BSD
 */

#include <algorithm>
#include <array>
#include <cstdio>
#include <functional>
#include <tuple>
#include <vector>

#include <mcl/bit/swap.hpp>
#include <mcl/stdint.hpp>

#include "./A32/testenv.h"
#include "./fuzz_util.h"
#include "./rand_int.h"
#include "dynarmic/common/fp/fpcr.h"
#include "dynarmic/common/fp/fpsr.h"
#include "dynarmic/frontend/A32/ITState.h"
#include "dynarmic/frontend/A32/a32_location_descriptor.h"
#include "dynarmic/frontend/A32/a32_types.h"
#include "dynarmic/frontend/A32/translate/a32_translate.h"
#include "dynarmic/interface/A32/a32.h"
#include "dynarmic/ir/basic_block.h"
#include "dynarmic/ir/location_descriptor.h"
#include "dynarmic/ir/opcodes.h"

// Must be declared last for all necessary operator<< to be declared prior to this.
#include <fmt/format.h>
#include <fmt/ostream.h>

namespace {
using namespace Dynarmic;

bool ShouldTestInst(u32 instruction, u32 pc, bool is_thumb, bool is_last_inst, A32::ITState it_state = {}) {
    const A32::LocationDescriptor location = A32::LocationDescriptor{pc, {}, {}}.SetTFlag(is_thumb).SetIT(it_state);
    IR::Block block{location};
    const bool should_continue = A32::TranslateSingleInstruction(block, location, instruction);

    if (!should_continue && !is_last_inst) {
        return false;
    }

    if (auto terminal = block.GetTerminal(); boost::get<IR::Term::Interpret>(&terminal)) {
        return false;
    }

    for (const auto& ir_inst : block) {
        switch (ir_inst.GetOpcode()) {
        case IR::Opcode::A32ExceptionRaised:
        case IR::Opcode::A32CallSupervisor:
        case IR::Opcode::A32CoprocInternalOperation:
        case IR::Opcode::A32CoprocSendOneWord:
        case IR::Opcode::A32CoprocSendTwoWords:
        case IR::Opcode::A32CoprocGetOneWord:
        case IR::Opcode::A32CoprocGetTwoWords:
        case IR::Opcode::A32CoprocLoadWords:
        case IR::Opcode::A32CoprocStoreWords:
            return false;
        default:
            continue;
        }
    }

    return true;
}

std::vector<u16> GenRandomThumbInst(u32 pc, bool is_last_inst, A32::ITState it_state = {}) {
    static const struct InstructionGeneratorInfo {
        std::vector<InstructionGenerator> generators;
        std::vector<InstructionGenerator> invalid;
    } instructions = [] {
        const std::vector<std::tuple<std::string, const char*>> list{
#define INST(fn, name, bitstring) {#fn, bitstring},
#include "dynarmic/frontend/A32/decoder/thumb16.inc"
#include "dynarmic/frontend/A32/decoder/thumb32.inc"
#undef INST
        };

        const std::vector<std::tuple<std::string, const char*>> vfp_list{
#define INST(fn, name, bitstring) {#fn, bitstring},
//#include "dynarmic/frontend/A32/decoder/vfp.inc"
#undef INST
        };

        const std::vector<std::tuple<std::string, const char*>> asimd_list{
#define INST(fn, name, bitstring) {#fn, bitstring},
//#include "dynarmic/frontend/A32/decoder/asimd.inc"
#undef INST
        };

        std::vector<InstructionGenerator> generators;
        std::vector<InstructionGenerator> invalid;

        // List of instructions not to test
        static constexpr std::array do_not_test{
            "thumb16_BKPT",
            "thumb16_IT",

            // Exclusive load/stores
            "thumb32_LDREX",
            "thumb32_LDREXB",
            "thumb32_LDREXD",
            "thumb32_LDREXH",
            "thumb32_STREX",
            "thumb32_STREXB",
            "thumb32_STREXD",
            "thumb32_STREXH",

            // Coprocessor
            "thumb32_CDP",
            "thumb32_LDC",
            "thumb32_MCR",
            "thumb32_MCRR",
            "thumb32_MRC",
            "thumb32_MRRC",
            "thumb32_STC",
        };

        for (const auto& [fn, bitstring] : list) {
            if (std::find(do_not_test.begin(), do_not_test.end(), fn) != do_not_test.end()) {
                invalid.emplace_back(InstructionGenerator{bitstring});
                continue;
            }
            generators.emplace_back(InstructionGenerator{bitstring});
        }
        for (const auto& [fn, bs] : vfp_list) {
            std::string bitstring = bs;
            if (bitstring.substr(0, 4) == "cccc" || bitstring.substr(0, 4) == "----") {
                bitstring.replace(0, 4, "1110");
            }
            if (std::find(do_not_test.begin(), do_not_test.end(), fn) != do_not_test.end()) {
                invalid.emplace_back(InstructionGenerator{bitstring.c_str()});
                continue;
            }
            generators.emplace_back(InstructionGenerator{bitstring.c_str()});
        }
        for (const auto& [fn, bs] : asimd_list) {
            std::string bitstring = bs;
            if (bitstring.substr(0, 7) == "1111001") {
                const char U = bitstring[7];
                bitstring.replace(0, 8, "111-1111");
                bitstring[3] = U;
            } else if (bitstring.substr(0, 8) == "11110100") {
                bitstring.replace(0, 8, "11111001");
            } else {
                ASSERT_FALSE("Unhandled ASIMD instruction: {} {}", fn, bs);
            }
            if (std::find(do_not_test.begin(), do_not_test.end(), fn) != do_not_test.end()) {
                invalid.emplace_back(InstructionGenerator{bitstring.c_str()});
                continue;
            }
            generators.emplace_back(InstructionGenerator{bitstring.c_str()});
        }
        return InstructionGeneratorInfo{generators, invalid};
    }();

    while (true) {
        const size_t index = RandInt<size_t>(0, instructions.generators.size() - 1);
        const u32 inst = instructions.generators[index].Generate();
        const bool is_four_bytes = (inst >> 16) != 0;

        if (ShouldTestInst(is_four_bytes ? mcl::bit::swap_halves_32(inst) : inst, pc, true, is_last_inst, it_state)) {
            if (is_four_bytes)
                return {static_cast<u16>(inst >> 16), static_cast<u16>(inst)};
            return {static_cast<u16>(inst)};
        }
    }
}

template<typename TestEnv>
Dynarmic::A32::UserConfig GetUserConfig(TestEnv& testenv) {
    Dynarmic::A32::UserConfig user_config;
    user_config.optimizations &= ~OptimizationFlag::FastDispatch;
    user_config.callbacks = &testenv;
    return user_config;
}

template<typename TestEnv>
static void RunTestInstance(Dynarmic::A32::Jit& jit,
                            TestEnv& jit_env,
                            const std::array<u32, 16>& regs,
                            const std::array<u32, 64>& vecs,
                            const std::vector<typename TestEnv::InstructionType>& instructions,
                            const u32 cpsr,
                            const u32 fpscr,
                            const size_t ticks_left) {
    const u32 initial_pc = regs[15];
    const u32 num_words = initial_pc / sizeof(typename TestEnv::InstructionType);
    const u32 code_mem_size = num_words + static_cast<u32>(instructions.size());

    jit_env.code_mem.resize(code_mem_size);
    std::fill(jit_env.code_mem.begin(), jit_env.code_mem.end(), TestEnv::infinite_loop);

    std::copy(instructions.begin(), instructions.end(), jit_env.code_mem.begin() + num_words);
    jit_env.PadCodeMem();
    jit_env.modified_memory.clear();
    jit_env.interrupts.clear();

    jit.Regs() = regs;
    jit.ExtRegs() = vecs;
    jit.SetFpscr(fpscr);
    jit.SetCpsr(cpsr);
    jit.ClearCache();

    jit_env.ticks_left = ticks_left;
    jit.Run();

    fmt::print("instructions: ");
    for (auto instruction : instructions) {
        if constexpr (sizeof(decltype(instruction)) == 2) {
            fmt::print("{:04x}", instruction);
        } else {
            fmt::print("{:08x}", instruction);
        }
    }
    fmt::print("\n");

    fmt::print("initial_regs: ");
    for (u32 i : regs) {
        fmt::print("{:08x}", i);
    }
    fmt::print("\n");
    fmt::print("initial_vecs: ");
    for (u32 i : vecs) {
        fmt::print("{:08x}", i);
    }
    fmt::print("\n");
    fmt::print("initial_cpsr: {:08x}\n", cpsr);
    fmt::print("initial_fpcr: {:08x}\n", fpscr);

    fmt::print("final_regs: ");
    for (u32 i : jit.Regs()) {
        fmt::print("{:08x}", i);
    }
    fmt::print("\n");
    fmt::print("final_vecs: ");
    for (u32 i : jit.ExtRegs()) {
        fmt::print("{:08x}", i);
    }
    fmt::print("\n");
    fmt::print("final_cpsr: {:08x}\n", jit.Cpsr());
    fmt::print("final_fpsr: {:08x}\n", jit.Fpscr());

    fmt::print("mod_mem: ");
    for (auto [addr, value] : jit_env.modified_memory) {
        fmt::print("{:08x}:{:02x} ", addr, value);
    }
    fmt::print("\n");

    fmt::print("interrupts:\n");
    for (const auto& i : jit_env.interrupts) {
        std::puts(i.c_str());
    }

    fmt::print("===\n");
}
}  // Anonymous namespace

int main(int, char*[]) {
    detail::g_rand_int_generator.seed(42);

    ThumbTestEnv jit_env{};
    Dynarmic::A32::Jit jit{GetUserConfig(jit_env)};

    std::array<u32, 16> regs;
    std::array<u32, 64> ext_reg;
    std::vector<u16> instructions;

    for (size_t iteration = 0; iteration < 1000000; ++iteration) {
        std::generate(regs.begin(), regs.end(), [] { return RandInt<u32>(0, ~u32(0)); });
        std::generate(ext_reg.begin(), ext_reg.end(), [] { return RandInt<u32>(0, ~u32(0)); });

        instructions = GenRandomThumbInst(0, true);

        const u32 start_address = 100;
        const u32 cpsr = (RandInt<u32>(0, 0xF) << 28) | 0x1F0;
        const u32 fpcr = RandomFpcr();

        regs[15] = start_address;
        RunTestInstance(jit, jit_env, regs, ext_reg, instructions, cpsr, fpcr, 1);
    }

    return 0;
}