#include "AutoScreenshot.h"

#include "NativeRenderer.h"

#include <chrono>
#include <cctype>
#include <cstdlib>
#include <cstdio>
#include <sstream>
#include <system_error>

namespace XCEngine::UI::Editor::Host {

namespace {

bool IsAutoCaptureOnStartupEnabled() {
    const char* value = std::getenv("XCUI_AUTO_CAPTURE_ON_STARTUP");
    if (value == nullptr || value[0] == '\0') {
        return false;
    }

    std::string normalized = value;
    for (char& character : normalized) {
        character = static_cast<char>(std::tolower(static_cast<unsigned char>(character)));
    }

    return normalized != "0" &&
        normalized != "false" &&
        normalized != "off" &&
        normalized != "no";
}

} // namespace

void AutoScreenshotController::Initialize(const std::filesystem::path& captureRoot) {
    m_captureRoot = captureRoot.lexically_normal();
    m_historyRoot = (m_captureRoot / "history").lexically_normal();
    m_latestCapturePath = (m_captureRoot / "latest.png").lexically_normal();
    m_captureCount = 0;
    m_capturePending = false;
    m_pendingReason.clear();
    m_lastCaptureSummary.clear();
    m_lastCaptureError.clear();
    if (IsAutoCaptureOnStartupEnabled()) {
        RequestCapture("startup");
    }
}

void AutoScreenshotController::Shutdown() {
    m_capturePending = false;
    m_pendingReason.clear();
}

void AutoScreenshotController::RequestCapture(std::string reason) {
    m_pendingReason = reason.empty() ? "capture" : std::move(reason);
    m_capturePending = true;
}

void AutoScreenshotController::CaptureIfRequested(
    NativeRenderer& renderer,
    const ::XCEngine::UI::UIDrawData& drawData,
    unsigned int width,
    unsigned int height,
    bool framePresented) {
    if (!m_capturePending) {
        return;
    }

    if (!framePresented || drawData.Empty() || width == 0u || height == 0u) {
        return;
    }

    std::error_code errorCode = {};
    std::filesystem::create_directories(m_captureRoot, errorCode);
    if (errorCode) {
        m_lastCaptureError = "Failed to create screenshot directory: " + m_captureRoot.string();
        m_lastCaptureSummary = "AutoShot failed";
        m_capturePending = false;
        return;
    }

    std::filesystem::create_directories(m_historyRoot, errorCode);
    if (errorCode) {
        m_lastCaptureError = "Failed to create screenshot directory: " + m_historyRoot.string();
        m_lastCaptureSummary = "AutoShot failed";
        m_capturePending = false;
        return;
    }

    std::string captureError = {};
    const std::filesystem::path historyPath = BuildHistoryCapturePath(m_pendingReason);
    if (!renderer.CaptureToPng(drawData, width, height, historyPath, captureError)) {
        m_lastCaptureError = std::move(captureError);
        m_lastCaptureSummary = "AutoShot failed";
        m_capturePending = false;
        return;
    }

    errorCode.clear();
    std::filesystem::copy_file(
        historyPath,
        m_latestCapturePath,
        std::filesystem::copy_options::overwrite_existing,
        errorCode);
    if (errorCode) {
        m_lastCaptureError = "Failed to update latest screenshot: " + m_latestCapturePath.string();
        m_lastCaptureSummary = "AutoShot failed";
        m_capturePending = false;
        return;
    }

    ++m_captureCount;
    m_lastCaptureError.clear();
    m_lastCaptureSummary =
        "Shot: latest.png | " + historyPath.filename().string();
    m_capturePending = false;
    m_pendingReason.clear();
}

bool AutoScreenshotController::HasPendingCapture() const {
    return m_capturePending;
}

const std::filesystem::path& AutoScreenshotController::GetLatestCapturePath() const {
    return m_latestCapturePath;
}

const std::string& AutoScreenshotController::GetLastCaptureSummary() const {
    return m_lastCaptureSummary;
}

const std::string& AutoScreenshotController::GetLastCaptureError() const {
    return m_lastCaptureError;
}

std::filesystem::path AutoScreenshotController::BuildHistoryCapturePath(std::string_view reason) const {
    std::ostringstream filename;
    filename << BuildTimestampString()
             << '_'
             << (m_captureCount + 1u)
             << '_'
             << SanitizeReason(reason)
             << ".png";
    return (m_historyRoot / filename.str()).lexically_normal();
}

std::string AutoScreenshotController::BuildTimestampString() {
    const auto now = std::chrono::system_clock::now();
    const std::time_t currentTime = std::chrono::system_clock::to_time_t(now);
    std::tm localTime = {};
    localtime_s(&localTime, &currentTime);

    char buffer[32] = {};
    std::snprintf(
        buffer,
        sizeof(buffer),
        "%04d%02d%02d_%02d%02d%02d",
        localTime.tm_year + 1900,
        localTime.tm_mon + 1,
        localTime.tm_mday,
        localTime.tm_hour,
        localTime.tm_min,
        localTime.tm_sec);
    return buffer;
}

std::string AutoScreenshotController::SanitizeReason(std::string_view reason) {
    std::string sanitized = {};
    sanitized.reserve(reason.size());

    bool lastWasSeparator = false;
    for (const unsigned char value : reason) {
        if (std::isalnum(value)) {
            sanitized.push_back(static_cast<char>(std::tolower(value)));
            lastWasSeparator = false;
            continue;
        }

        if (!lastWasSeparator) {
            sanitized.push_back('_');
            lastWasSeparator = true;
        }
    }

    while (!sanitized.empty() && sanitized.front() == '_') {
        sanitized.erase(sanitized.begin());
    }
    while (!sanitized.empty() && sanitized.back() == '_') {
        sanitized.pop_back();
    }

    return sanitized.empty() ? "capture" : sanitized;
}

} // namespace XCEngine::UI::Editor::Host