#include "app_keys.h"
#include "gnss_app.h"

#include <Arduino.h>

#include <cmath>
#include <cstdio>

#include "geo_format.h"
#include "ui/canvas.h"
#include "ui/fonts.h"
#include "ui/theme.h"

namespace roro {

using namespace gnss;

namespace {

// One colour per constellation, readable in the 8-bit frame buffer.
uint16_t colorOf(Constellation c) {
    switch (c) {
        case Constellation::Gps: return theme::kAccent;
        case Constellation::Glonass: return 0xF8C8;  // red
        case Constellation::Galileo: return theme::kMessage;
        case Constellation::BeiDou: return 0xFEA0;   // yellow
        case Constellation::Qzss: return 0xC99F;     // violet
        default: return theme::kText;
    }
}

const char* fixLabel(FixType f) { return f == FixType::ThreeD ? "3D Fix" : f == FixType::TwoD ? "2D Fix" : "No Fix"; }

std::string duration(uint32_t ms) {
    uint32_t s = ms / 1000;
    char buf[24];
    if (s < 60) std::snprintf(buf, sizeof buf, "%lu s", (unsigned long)s);
    else std::snprintf(buf, sizeof buf, "%lu min %02lu s", (unsigned long)(s / 60), (unsigned long)(s % 60));
    return buf;
}

}  // namespace

bool GnssApp::onKey(const KeyEvent& e) {
    if (e.key == Key::Tab) {
        sky_ = !sky_;
        requestRedraw();
        return true;
    }
    if (e.key == Key::Char && (e.ch == 'r' || e.ch == 'R')) {  // record a Track, or stop it
        if (gnss_.tracking()) gnss_.stopTrack();
        else {
            refusal_ = gnss_.startTrack(millis());
            refusalMs_ = millis();
        }
        requestRedraw();
        return true;
    }
    return false;  // Back leaves the App
}

void GnssApp::update(uint32_t nowMs) {
    if (nowMs - lastDrawMs_ >= 1000) {  // the receiver reports once a second
        lastDrawMs_ = nowMs;
        requestRedraw();
    }
}

void GnssApp::draw(Canvas& c) {
    c.setTextDatum(top_left);
    const auto& area = theme::kContent;
    if (!gnss_.on()) {
        c.setFont(&fonts::bold);
        c.setTextColor(theme::kText);
        bool held = gnss_.heldForLora();
        c.drawString(held ? "GNSS is paused" : "GNSS is off", 4, area.y + 4);
        c.setFont(&fonts::body);
        c.setTextColor(theme::kMuted);
        c.drawString(held ? "The LoRa radio is listening, and" : "Settings > GNSS turns it on.", 4, area.y + 22);
        if (held) c.drawString("Settings pauses GNSS for it.", 4, area.y + 22 + theme::kLineHeight);
        return;
    }
    sky_ ? drawSky(c) : drawPosition(c);
}

void GnssApp::help(std::vector<KeyHelp>& out) const {
    keys::add(out, keys::kGnss);
}

void GnssApp::drawPosition(Canvas& c) {
    const auto& area = theme::kContent;
    const GnssState& s = gnss_.state();
    uint32_t now = millis();
    int used = 0;
    for (auto& sat : s.satellites) used += sat.used;
    char line[64];

    c.setFont(&fonts::bold);
    c.setTextColor(s.fix == FixType::None ? theme::kWarning : theme::kMessage);
    if (!gnss_.receiving(now)) std::snprintf(line, sizeof line, "No data from the receiver");
    else if (s.fix == FixType::None)
        std::snprintf(line, sizeof line, "Searching: %u in view, %s", (unsigned)s.satellites.size(),
                      duration(now - gnss_.onSinceMs()).c_str());
    else std::snprintf(line, sizeof line, "%s, %d of %u satellites", fixLabel(s.fix), s.satellitesUsed,
                       (unsigned)s.satellites.size());
    c.drawString(line, 4, area.y + 2);

    c.setFont(&fonts::body);
    int y = area.y + 19;
    auto row = [&](const char* label, const std::string& value) {
        c.setTextColor(theme::kMuted);
        c.drawString(label, 4, y);
        c.setTextColor(theme::kText);
        c.drawString(value.c_str(), 64, y);
        y += theme::kLineHeight;
    };
    bool dms = settings_.getBool(Setting::CoordinatesDms);
    if (s.positionValid) {
        row("Lat", dms ? formatDms(s.latitude, true) : formatDecimal(s.latitude, true));
        row("Lon", dms ? formatDms(s.longitude, false) : formatDecimal(s.longitude, false));
        row("Locator", maidenhead(s.latitude, s.longitude));
        std::snprintf(line, sizeof line, s.altitudeValid ? "%.0f m" : "-", s.altitudeM);
        row("Altitude", line);
        if (s.courseValid && s.speedKmh >= 1.0f)
            std::snprintf(line, sizeof line, "%.1f km/h, %.0f\xC2\xB0", s.speedKmh, s.courseDeg);
        else std::snprintf(line, sizeof line, "%.1f km/h", s.speedKmh);
        row("Speed", line);
    } else {
        row("Lat", "-");
        row("Lon", "-");
        y += theme::kLineHeight * 3;
    }
    std::snprintf(line, sizeof line, "%.1f", s.hdop);
    row("HDOP", s.fix == FixType::None ? "-" : line);
    if (s.timeValid) std::snprintf(line, sizeof line, "%02d:%02d:%02d UTC", s.hour, s.minute, s.second);
    row("Time", s.timeValid ? line : "-");

    // The Track line, at the bottom left.
    c.setFont(&fonts::small);
    if (gnss_.tracking()) {
        c.setTextColor(theme::kWarning);
        std::snprintf(line, sizeof line, "REC %d point%s, %s", gnss_.trackPoints(),
                      gnss_.trackPoints() == 1 ? "" : "s", duration(now - gnss_.trackStartMs()).c_str());
    } else if (!refusal_.empty() && now - refusalMs_ < 4000) {
        c.setTextColor(theme::kWarning);
        std::snprintf(line, sizeof line, "%s", refusal_.c_str());
    } else line[0] = 0;
    c.drawString(line, 4, area.y + area.h - 9);
}

void GnssApp::drawSky(Canvas& c) {
    const auto& area = theme::kContent;
    const GnssState& s = gnss_.state();
    const int radius = (area.h - 6) / 2, cx = 4 + radius, cy = area.y + area.h / 2;

    // The sky from above: horizon, 30° and 60° elevation rings, north up.
    c.drawCircle(cx, cy, radius, theme::kMuted);
    c.drawCircle(cx, cy, radius * 2 / 3, 0x4208);
    c.drawCircle(cx, cy, radius / 3, 0x4208);
    c.drawFastHLine(cx - radius, cy, 2 * radius, 0x4208);
    c.drawFastVLine(cx, cy - radius, 2 * radius, 0x4208);
    c.setFont(&fonts::small);
    c.setTextColor(theme::kMuted);
    c.setTextDatum(middle_center);
    auto compass = [&](const char* letter, int x, int y) {
        c.fillRect(x - 3, y - 4, 7, 9, theme::kBackground);  // off the lines, so it reads
        c.drawString(letter, x, y);
    };
    compass("N", cx, cy - radius + 5);
    compass("S", cx, cy + radius - 4);
    compass("E", cx + radius - 4, cy);
    compass("W", cx - radius + 4, cy);
    c.setTextDatum(top_left);

    int inView[8] = {}, usedBy[8] = {};
    for (auto& sat : s.satellites) {
        int k = static_cast<int>(sat.system);
        inView[k]++;
        usedBy[k] += sat.used;
        SkyPoint p = skyPosition(sat.azimuth, sat.elevation, cx, cy, radius - 3);
        uint16_t color = colorOf(sat.system);
        if (sat.used) c.fillCircle(p.x, p.y, 3, color);
        else c.drawCircle(p.x, p.y, 3, sat.snr < 0 ? theme::kMuted : color);
    }

    // Legend: used / in view per constellation, then the Fix.
    int x = cx + radius + 12, y = area.y + 4;
    c.setFont(&fonts::body);
    for (int k = 1; k < 7; k++) {
        if (!inView[k]) continue;
        auto system = static_cast<Constellation>(k);
        c.fillCircle(x + 3, y + 6, 3, colorOf(system));
        char line[32];
        std::snprintf(line, sizeof line, "%-8s%d/%d", constellationName(system), usedBy[k], inView[k]);
        c.setTextColor(theme::kText);
        c.drawString(line, x + 10, y);
        y += theme::kLineHeight;
    }
    if (s.satellites.empty()) {
        c.setTextColor(theme::kMuted);
        c.drawString("No satellites", x, y);
        y += theme::kLineHeight;
    }
    c.setTextColor(s.fix == FixType::None ? theme::kWarning : theme::kMessage);
    c.drawString(fixLabel(s.fix), x, y + 4);
    c.setFont(&fonts::small);
    c.setTextColor(theme::kMuted);
    c.drawString("filled: in use", x, area.y + area.h - 20);
}

}  // namespace roro