#include "sweep_view.h"

#include <algorithm>

namespace roro::lora {

namespace {
constexpr int kPeakAboveFloorDb = 10;
constexpr size_t kMaxPeaks = 3;
}  // namespace

SweepStats summarize(const int8_t* dbm, size_t steps, uint32_t fromHz, uint32_t stepHz) {
    SweepStats s;
    if (!steps) return s;
    std::vector<int8_t> sorted(dbm, dbm + steps);
    std::nth_element(sorted.begin(), sorted.begin() + steps / 2, sorted.end());
    s.floor = sorted[steps / 2];
    s.top = *std::max_element(dbm, dbm + steps);
    for (size_t i = 0; i < steps; ++i) {
        int v = dbm[i];
        bool localMax = (i == 0 || v >= dbm[i - 1]) && (i + 1 == steps || v > dbm[i + 1]);
        if (localMax && v >= s.floor + kPeakAboveFloorDb) s.peaks.push_back({fromHz + static_cast<uint32_t>(i) * stepHz, v});
    }
    std::stable_sort(s.peaks.begin(), s.peaks.end(), [](const SweepPeak& a, const SweepPeak& b) { return a.dbm > b.dbm; });
    if (s.peaks.size() > kMaxPeaks) s.peaks.resize(kMaxPeaks);
    return s;
}

uint8_t heatLevel(int dbm, int low, int high) {
    if (dbm <= low) return 0;
    if (dbm >= high) return 255;
    return static_cast<uint8_t>((dbm - low) * 255 / (high - low) + ((dbm - low) * 255 % (high - low) ? 1 : 0));
}

uint16_t heatColor(uint8_t level) {
    // Five segments of 51 steps each.
    auto rgb = [](int r, int g, int b) { return static_cast<uint16_t>((r >> 3) << 11 | (g >> 2) << 5 | (b >> 3)); };
    int seg = std::min(level / 51, 4), t = (level - seg * 51) * 255 / 51;
    switch (seg) {
        case 0: return rgb(0, 0, t);              // black to blue
        case 1: return rgb(0, t, 255);            // blue to cyan
        case 2: return rgb(0, 255, 255 - t);      // cyan to green
        case 3: return rgb(t, 255, 0);            // green to yellow
        default: return rgb(255, 255 - t, 0);     // yellow to red
    }
}

}  // namespace roro::lora