// led/Bx6k1YyLedClient.cxx
#include "Bx6k1YyLedClient.hpp"

#include "BX6K1YYProtocol.hpp"

#include <arpa/inet.h>
#include <cerrno>
#include <chrono>
#include <cstdio>
#include <cstring>
#include <fcntl.h>
#include <iconv.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <poll.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#include <algorithm>
#include <vector>

namespace led {

namespace {

bool encodeUtf8(const std::string& in, const std::string& encoding, std::string& bytes) {
    if (encoding.empty() || encoding == "UTF-8" || encoding == "utf-8") {
        bytes = in;
        return true;
    }
    iconv_t cd = iconv_open(encoding.c_str(), "UTF-8//IGNORE");
    if (cd == reinterpret_cast<iconv_t>(-1)) return false;

    size_t inLeft  = in.size();
    size_t outLeft = in.size() * 4 + 16;
    std::vector<char> out(outLeft);
    char* inBuf  = const_cast<char*>(in.data());
    char* outBuf = out.data();

    size_t res = iconv(cd, &inBuf, &inLeft, &outBuf, &outLeft);
    iconv_close(cd);
    if (res == static_cast<size_t>(-1)) return false;
    bytes.assign(out.data(), out.size() - outLeft);
    return true;
}

bool setNonBlocking(int fd, bool nb) {
    int flags = fcntl(fd, F_GETFL, 0);
    if (flags < 0) return false;
    return fcntl(fd, F_SETFL, nb ? (flags | O_NONBLOCK) : (flags & ~O_NONBLOCK)) == 0;
}

bool connectWithTimeout(int fd, const sockaddr_in& addr, int timeoutMs) {
    int rc = ::connect(fd, reinterpret_cast<const sockaddr*>(&addr), sizeof(addr));
    if (rc == 0) return true;
    if (errno != EINPROGRESS) return false;
    pollfd pfd{fd, POLLOUT, 0};
    if (::poll(&pfd, 1, timeoutMs) <= 0) return false;
    int err = 0; socklen_t len = sizeof(err);
    if (getsockopt(fd, SOL_SOCKET, SO_ERROR, &err, &len) < 0) return false;
    return err == 0;
}

bool sendAll(int fd, const uint8_t* data, size_t len, int timeoutMs) {
    size_t sent = 0;
    while (sent < len) {
        pollfd pfd{fd, POLLOUT, 0};
        if (::poll(&pfd, 1, timeoutMs) <= 0) return false;
        ssize_t n = ::send(fd, data + sent, len - sent, MSG_NOSIGNAL);
        if (n <= 0) return false;
        sent += static_cast<size_t>(n);
    }
    return true;
}

// 收到至少一个 0x5A 字节或超时
bool recvUntilTail(int fd, std::vector<uint8_t>& buf, int timeoutMs) {
    uint8_t chunk[1024];
    auto deadline = std::chrono::steady_clock::now() + std::chrono::milliseconds(timeoutMs);
    while (true) {
        auto now = std::chrono::steady_clock::now();
        if (now >= deadline) return !buf.empty();
        int wait = static_cast<int>(
            std::chrono::duration_cast<std::chrono::milliseconds>(deadline - now).count());
        pollfd pfd{fd, POLLIN, 0};
        if (::poll(&pfd, 1, wait) <= 0) return !buf.empty();
        ssize_t n = ::recv(fd, chunk, sizeof(chunk), 0);
        if (n <= 0) return !buf.empty();
        buf.insert(buf.end(), chunk, chunk + n);
        if (std::find(buf.begin(), buf.end(), 0x5A) != buf.end()) return true;
    }
}

} // anonymous namespace

Bx6k1YyLedClient::Bx6k1YyLedClient(Config cfg) : m_cfg(std::move(cfg)) {}

Bx6k1YyLedClient::~Bx6k1YyLedClient() { closeSocket(); }

void Bx6k1YyLedClient::closeSocket() {
    if (m_fd >= 0) { ::close(m_fd); m_fd = -1; }
}

bool Bx6k1YyLedClient::ensureConnected(std::string& error) {
    if (m_fd >= 0) return true;

    int fd = ::socket(AF_INET, SOCK_STREAM, 0);
    if (fd < 0) { error = std::string("socket: ") + std::strerror(errno); return false; }
    setNonBlocking(fd, true);

    sockaddr_in addr{};
    addr.sin_family = AF_INET;
    addr.sin_port   = htons(m_cfg.port);
    if (inet_pton(AF_INET, m_cfg.ip.c_str(), &addr.sin_addr) != 1) {
        ::close(fd);
        error = "bad ip " + m_cfg.ip;
        return false;
    }
    if (!connectWithTimeout(fd, addr, m_cfg.connectTimeoutMs)) {
        ::close(fd);
        error = "connect " + m_cfg.ip + ":" + std::to_string(m_cfg.port) + " failed";
        return false;
    }
    setNonBlocking(fd, false);
    int one = 1;
    setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one));
    m_fd = fd;
    return true;
}

bool Bx6k1YyLedClient::queryScreenSize(int& outW, int& outH, std::string& error) {
    if (m_fd < 0) { error = "not connected"; return false; }
    auto frame = buildScreenParameterQueryFrame();
    if (!sendAll(m_fd, frame.data(), frame.size(), m_cfg.responseTimeoutMs)) {
        error = "send screen query failed"; return false;
    }
    std::vector<uint8_t> buf;
    if (!recvUntilTail(m_fd, buf, m_cfg.responseTimeoutMs)) {
        error = "recv screen query timeout"; return false;
    }
    auto head = std::find(buf.begin(), buf.end(), 0xA5);
    if (head == buf.end()) { error = "no head"; return false; }
    auto tailIt = std::find(buf.rbegin(), buf.rend(), 0x5A);
    if (tailIt == buf.rend()) { error = "no tail"; return false; }
    std::vector<uint8_t> phy1;
    std::vector<uint8_t> oneFrame(head, tailIt.base());
    if (!decodeFrame(oneFrame, phy1, error)) return false;
    return parseScreenDimensions(phy1, outW, outH, error);
}

bool Bx6k1YyLedClient::displayText(const std::string& utf8Text, int areaId, std::string& error) {
    if (!ensureConnected(error)) return false;

    if (m_screenW <= 0 || m_screenH <= 0) {
        int w = 0, h = 0;
        if (queryScreenSize(w, h, error)) {
            m_screenW = w; m_screenH = h;
        } else {
            // 查询失败：使用回退分辨率，不阻塞刷新
            m_screenW = m_cfg.fallbackScreenWidth;
            m_screenH = m_cfg.fallbackScreenHeight;
            error.clear();
        }
    }

    std::string encoded;
    if (!encodeUtf8(utf8Text, m_cfg.textEncoding, encoded)) {
        error = "encode failed"; return false;
    }

    const int  lineH         = m_screenH;        // 单行：使用整屏高度
    const bool isTemporary   = (areaId == kAreaTemporary);
    const int  timeoutSec    = isTemporary ? kTemporaryTimeoutSec : 0;
    const int  effectiveArea = (areaId == kAreaDefault) ? kAreaDefault : kAreaTemporary;

    std::vector<uint8_t> frame = buildDynamicTextFrame(encoded,
                                                         m_screenW, lineH,
                                                         effectiveArea,
                                                         isTemporary, timeoutSec);
    if (frame.empty()) { error = "build frame failed"; return false; }
    if (!sendAll(m_fd, frame.data(), frame.size(), m_cfg.responseTimeoutMs)) {
        error = "send frame failed"; return false;
    }
    std::vector<uint8_t> ack;
    recvUntilTail(m_fd, ack, m_cfg.responseTimeoutMs);  // 吃掉 ACK

    // [诊断] 解 ACK 帧并把 PHY1 全打出来，看控制卡是成功还是返回错误码
    if (!ack.empty()) {
        std::vector<uint8_t> phy1;
        std::string decErr;
        if (decodeFrame(ack, phy1, decErr)) {
            std::fprintf(stderr, "[Led] ACK phy1 (%zu B):", phy1.size());
            for (uint8_t b : phy1) std::fprintf(stderr, " %02X", b);
            std::fprintf(stderr, "\n");
            // BX-6K1-YY ACK payload 通常从 phy1[14] 起；payload[5]=ErrorCode，0=成功
            if (phy1.size() >= 20) {
                std::fprintf(stderr, "[Led] ACK payload[5] (ErrorCode) = 0x%02X\n",
                             phy1[14 + 5]);
            }
        } else {
            std::fprintf(stderr, "[Led] ACK decode failed: %s, raw (%zu B):",
                         decErr.c_str(), ack.size());
            for (uint8_t b : ack) std::fprintf(stderr, " %02X", b);
            std::fprintf(stderr, "\n");
        }
    } else {
        std::fprintf(stderr, "[Led] ACK empty (no response from controller)\n");
    }

    return true;
}

} // namespace led