#include "RasterDataProvider.h"
#include <QString>
#include <QDebug>
#include <QFile>
#include <QFileInfo>
#include <QRegularExpression>

#if HPPA_HAVE_GDAL
#include <gdal_priv.h>
#include <cpl_conv.h>
#endif

RasterDataProvider::RasterDataProvider(const QString& uri)
    : m_uri(uri), m_dataset(nullptr)
{
}

RasterDataProvider::~RasterDataProvider()
{
    close();
}

bool RasterDataProvider::open()
{
#if HPPA_HAVE_GDAL
    GDALAllRegister();
    m_dataset = (GDALDataset*)GDALOpen((const char*)m_uri.toLocal8Bit().constData(), GA_ReadOnly);
    if (!m_dataset) {
        qWarning() << "RasterDataProvider: failed to open dataset:" << m_uri;
        return false;
    }
    return true;
#else
    Q_UNUSED(m_uri);
    qWarning() << "RasterDataProvider: GDAL not available, open will fail.";
    return false;
#endif
}

void RasterDataProvider::close()
{
#if HPPA_HAVE_GDAL
    if (m_dataset) {
        GDALClose((GDALDatasetH)m_dataset);
        m_dataset = nullptr;
    }
#else
    m_dataset = nullptr;
#endif
}

int RasterDataProvider::bandCount() const
{
#if HPPA_HAVE_GDAL
    if (!m_dataset) return 0;
    return m_dataset->GetRasterCount();
#else
    Q_UNUSED(this);
    return 0;
#endif
}

int RasterDataProvider::width() const
{
#if HPPA_HAVE_GDAL
    if (!m_dataset) return 0;
    return m_dataset->GetRasterXSize();
#else
    Q_UNUSED(this);
    return 0;
#endif
}

int RasterDataProvider::height() const
{
#if HPPA_HAVE_GDAL
    if (!m_dataset) return 0;
    return m_dataset->GetRasterYSize();
#else
    Q_UNUSED(this);
    return 0;
#endif
}

bool RasterDataProvider::isValidPixel(int x, int y) const
{
    const int w = width();
    const int h = height();
    return x >= 0 && y >= 0 && x < w && y < h;
}

std::vector<double> RasterDataProvider::parseEnviHdrWavelengths() const
{
    std::vector<double> res;

    QFileInfo fi(m_uri);
    QString hdrPath = fi.path() + "/" + fi.completeBaseName() + ".hdr";
    QFile hdr(hdrPath);
    if (!hdr.open(QIODevice::ReadOnly | QIODevice::Text)) {
        return res;
    }

    QString text = QString::fromLocal8Bit(hdr.readAll());
    hdr.close();

    QRegularExpression rx("wavelength\\s*=\\s*\\{([^}]*)\\}", QRegularExpression::CaseInsensitiveOption | QRegularExpression::DotMatchesEverythingOption);
    QRegularExpressionMatch m = rx.match(text);
    if (!m.hasMatch()) {
        return res;
    }

    const QString body = m.captured(1);
    const QStringList parts = body.split(',', QString::SkipEmptyParts);
    res.reserve(parts.size());
    for (const QString& p : parts) {
        bool ok = false;
        double v = p.trimmed().toDouble(&ok);
        if (ok) {
            res.push_back(v);
        }
    }

    return res;
}

std::vector<double> RasterDataProvider::bandWavelengths() const
{
    std::vector<double> res;
#if HPPA_HAVE_GDAL
    if (!m_dataset) return res;

    // 1) Try ENVI dataset-level metadata first: wavelength = { ... }
    const char* dsWave = m_dataset->GetMetadataItem("wavelength", "ENVI");
    if (!dsWave) dsWave = m_dataset->GetMetadataItem("Wavelength", "ENVI");
    if (dsWave) {
        QString dsWaveStr = QString::fromLocal8Bit(dsWave);
        dsWaveStr.remove('{').remove('}');
        const QStringList parts = dsWaveStr.split(',', QString::SkipEmptyParts);
        res.reserve(parts.size());
        for (const QString& p : parts) {
            bool ok = false;
            double v = p.trimmed().toDouble(&ok);
            if (ok) res.push_back(v);
        }
        if (!res.empty()) return res;
    }

    // 2) Try per-band metadata
    for (int i = 1; i <= m_dataset->GetRasterCount(); ++i) {
        GDALRasterBand* band = m_dataset->GetRasterBand(i);
        if (!band) continue;
        const char* val = band->GetMetadataItem("Wavelength");
        if (!val) val = band->GetMetadataItem("wavelength");
        if (val) {
            bool ok = false;
            double v = QString::fromLocal8Bit(val).trimmed().toDouble(&ok);
            res.push_back(ok ? v : -1.0);
        } else {
            res.push_back(-1.0);
        }
    }
    if (!res.empty()) return res;
#endif

    // 3) Fallback: parse ENVI .hdr directly
    return parseEnviHdrWavelengths();
}

bool RasterDataProvider::readPixelSpectrum(int x, int y, std::vector<double>& outSpectrum) const
{
#if HPPA_HAVE_GDAL
    outSpectrum.clear();
    if (!m_dataset) return false;
    if (!isValidPixel(x, y)) return false;

    const int bands = m_dataset->GetRasterCount();
    if (bands <= 0) return false;

    outSpectrum.resize(bands);
    for (int i = 0; i < bands; ++i) {
        GDALRasterBand* band = m_dataset->GetRasterBand(i + 1);
        if (!band) return false;

        float value = 0.0f;
        CPLErr err = band->RasterIO(
            GF_Read,
            x, y,
            1, 1,
            &value,
            1, 1,
            GDT_Float32,
            0, 0);

        if (err != CE_None) return false;
        outSpectrum[i] = static_cast<double>(value);
    }

    return true;
#else
    Q_UNUSED(x);
    Q_UNUSED(y);
    Q_UNUSED(outSpectrum);
    return false;
#endif
}

bool RasterDataProvider::readBandAsFloat(int bandIndex, std::vector<float>& outBuffer) const
{
#if HPPA_HAVE_GDAL
    if (!m_dataset) return false;
    int bands = m_dataset->GetRasterCount();
    if (bandIndex < 0 || bandIndex >= bands) return false;
    GDALRasterBand* band = m_dataset->GetRasterBand(bandIndex + 1);
    if (!band) return false;
    int w = m_dataset->GetRasterXSize();
    int h = m_dataset->GetRasterYSize();
    outBuffer.assign(w * h, 0.0f);
    CPLErr err = band->RasterIO(GF_Read, 0, 0, w, h, outBuffer.data(), w, h, GDT_Float32, 0, 0);
    return err == CE_None;
#else
    Q_UNUSED(bandIndex);
    Q_UNUSED(outBuffer);
    return false;
#endif
}