package de.dennisguse.opentracks.services.announcement;

import static android.text.Spanned.SPAN_INCLUSIVE_EXCLUSIVE;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceAverageHeartRate;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceAverageSpeedPace;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceHeartRateCurrent;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceLapHeartRate;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceLapPower;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceLapSpeedPace;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceMovingTime;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceTime;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceTotalDistance;
import static de.dennisguse.opentracks.settings.PreferencesUtils.shouldVoiceAnnounceUnit;

import android.content.Context;
import android.icu.text.MessageFormat;
import android.text.Spannable;
import android.text.SpannableString;
import android.text.SpannableStringBuilder;
import android.text.style.TtsSpan;
import android.util.Pair;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.time.Duration;
import java.time.OffsetDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.FormatStyle;
import java.util.Map;

import de.dennisguse.opentracks.R;
import de.dennisguse.opentracks.data.models.Distance;
import de.dennisguse.opentracks.data.models.HeartRate;
import de.dennisguse.opentracks.data.models.Speed;
import de.dennisguse.opentracks.data.models.Track;
import de.dennisguse.opentracks.sensors.sensorData.SensorDataSet;
import de.dennisguse.opentracks.settings.UnitSystem;
import de.dennisguse.opentracks.stats.SensorStatistics;
import de.dennisguse.opentracks.stats.TrackStatistics;
import de.dennisguse.opentracks.ui.intervals.IntervalStatistics;
import de.dennisguse.opentracks.util.StringUtils;

class VoiceAnnouncementUtils {

    private VoiceAnnouncementUtils() {
    }

    static Spannable createIdle(Context context) {
        return new SpannableStringBuilder()
                .append(context.getString(R.string.voiceIdle));
    }

    static Spannable createStatistics(Context context, Track track, SensorDataSet sensorDataSet, UnitSystem unitSystem, boolean isReportSpeed, @Nullable IntervalStatistics.Interval currentInterval, @Nullable SensorStatistics sensorStatistics) {
        TrackStatistics trackStatistics = track.getTrackStatistics();

        SpannableStringBuilder builder = new SpannableStringBuilder();

        if (shouldVoiceAnnounceTime()) {
            appendTime(builder, track.getStopTime());
        }

        Distance totalDistance = trackStatistics.getTotalDistance();
        Speed averageMovingSpeed = trackStatistics.getAverageMovingSpeed();
        Speed currentDistancePerTime = currentInterval != null ? currentInterval.getSpeed() : null;

        int perUnitStringId = R.string.empty;
        int distanceId = R.string.voiceDistance;
        int speedId = R.string.voiceSpeed;
        String unitDistanceTTS = StringUtils.EMPTY;
        String unitSpeedTTS = StringUtils.EMPTY;

        if(shouldVoiceAnnounceUnit()) {
            switch (unitSystem) {
                case METRIC -> {
                    perUnitStringId = R.string.voice_per_kilometer;
                    distanceId = R.string.voiceDistanceKilometersPlural;
                    speedId = R.string.voiceSpeedKilometersPerHourPlural;
                    unitDistanceTTS = "kilometer";
                    unitSpeedTTS = "kilometer per hour";
                }
                case IMPERIAL_FEET, IMPERIAL_METER -> {
                    perUnitStringId = R.string.voice_per_mile;
                    distanceId = R.string.voiceDistanceMilesPlural;
                    speedId = R.string.voiceSpeedMilesPerHourPlural;
                    unitDistanceTTS = "mile";
                    unitSpeedTTS = "mile per hour";
                }
                case NAUTICAL_IMPERIAL -> {
                    perUnitStringId = R.string.voice_per_nautical_mile;
                    distanceId = R.string.voiceDistanceNauticalMilesPlural;
                    speedId = R.string.voiceSpeedMKnotsPlural;
                    unitDistanceTTS = "nautical mile";
                    unitSpeedTTS = "knots";
                }
                default -> throw new RuntimeException("Not implemented");
            }
        }

        double distanceInUnit = totalDistance.toKM_Miles(unitSystem);

        if (shouldVoiceAnnounceTotalDistance()) {
            builder.append(context.getString(R.string.total_distance));
            // Units should always be english singular for TTS.
            // See https://developer.android.com/reference/android/text/style/TtsSpan?hl=en#TYPE_MEASURE
            String template = context.getResources().getString(distanceId);
            appendDecimalUnit(builder, MessageFormat.format(template, Map.of("n", distanceInUnit)), distanceInUnit, 1, unitDistanceTTS);
            // Punctuation helps introduce natural pauses in TTS
            builder.append(".");
        }

        boolean hasTravelledDistance = !totalDistance.isZero();

        // Announce time
        Duration movingTime = trackStatistics.getMovingTime();
        if (shouldVoiceAnnounceMovingTime() && hasTravelledDistance && !movingTime.isZero()) {
            appendDuration(context, builder, movingTime);
            builder.append(".");
        }

        if (hasTravelledDistance) {
            if (isReportSpeed) {
                if (shouldVoiceAnnounceAverageSpeedPace()) {
                    double speedInUnit = averageMovingSpeed.to(unitSystem);
                    builder.append(" ")
                            .append(context.getString(R.string.speed));
                    String template = context.getResources().getString(speedId);
                    appendDecimalUnit(builder, MessageFormat.format(template, Map.of("n", speedInUnit)), speedInUnit, 1, unitSpeedTTS);
                    builder.append(".");
                }
                if (shouldVoiceAnnounceLapSpeedPace() && currentDistancePerTime != null) {
                    double currentDistancePerTimeInUnit = currentDistancePerTime.to(unitSystem);
                    if (currentDistancePerTimeInUnit > 0) {
                        builder.append(" ")
                                .append(context.getString(R.string.lap_speed));
                        String template = context.getResources().getString(speedId);
                        appendDecimalUnit(builder, MessageFormat.format(template, Map.of("n", currentDistancePerTimeInUnit)), currentDistancePerTimeInUnit, 1, unitSpeedTTS);
                        builder.append(".");
                    }
                }
            } else {
                if (shouldVoiceAnnounceAverageSpeedPace()) {
                    Duration time = averageMovingSpeed.toPace(unitSystem);
                    builder.append(" ")
                            .append(context.getString(R.string.pace));
                    appendDuration(context, builder, time);
                    builder.append(" ")
                            .append(context.getString(perUnitStringId))
                            .append(".");
                }

                if (shouldVoiceAnnounceLapSpeedPace() && currentDistancePerTime != null) {
                    Duration currentTime = currentDistancePerTime.toPace(unitSystem);
                    builder.append(" ")
                            .append(context.getString(R.string.lap_time));
                    appendDuration(context, builder, currentTime);
                    builder.append(" ")
                            .append(context.getString(perUnitStringId))
                            .append(".");
                }
            }
        }

        Pair<HeartRate, String> heartrate = sensorDataSet.getHeartRate();
        if (shouldVoiceAnnounceHeartRateCurrent() && heartrate != null && heartrate.first != null) { //TODO Check has an announcable value?
            int averageHeartRate = Math.round(heartrate.first.getBPM());

            builder.append(" ")
                    .append(context.getString(R.string.current_heart_rate));
            appendCardinal(builder, context.getString(R.string.sensor_state_heart_rate_value, averageHeartRate), averageHeartRate);
            builder.append(".");
        }
        if (hasTravelledDistance) {
            if (shouldVoiceAnnounceAverageHeartRate() && sensorStatistics != null && sensorStatistics.hasHeartRate()) {
                int averageHeartRate = Math.round(sensorStatistics.avgHeartRate().getBPM());

                builder.append(" ")
                        .append(context.getString(R.string.average_heart_rate));
                appendCardinal(builder, context.getString(R.string.sensor_state_heart_rate_value, averageHeartRate), averageHeartRate);
                builder.append(".");
            }
            if (shouldVoiceAnnounceLapHeartRate() && currentInterval != null && currentInterval.hasAverageHeartRate()) {
                int currentHeartRate = Math.round(currentInterval.getAverageHeartRate().getBPM());

                builder.append(" ")
                        .append(context.getString(R.string.lap_heart_rate));
                appendCardinal(builder, context.getString(R.string.sensor_state_heart_rate_value, currentHeartRate), currentHeartRate);
                builder.append(".");
            }

            if (shouldVoiceAnnounceLapPower() && currentInterval != null && currentInterval.hasAveragePower()) {
                int currentPower = Math.round(currentInterval.getAveragePower().getW());
                if (shouldVoiceAnnounceUnit()) {
                    String template = context.getResources().getString(R.string.power_x_watt);
                    builder.append(" ")
                            .append(MessageFormat.format(template, Map.of("x", currentPower)));
                } else {
                    builder.append(" ").append(context.getString(R.string.power)).append(" ");
                    builder.append(String.valueOf(currentPower));
                }
                builder.append(".");
            }
        }
        return builder;
    }

    private static void appendDuration(@NonNull Context context, @NonNull SpannableStringBuilder builder, @NonNull Duration duration) {
        int hours = (int) (duration.toHours());
        int minutes = (int) (duration.toMinutes() % 60);
        int seconds = (int) (duration.getSeconds() % 60);

        if (hours > 0) {
            String template = context.getResources().getString(R.string.voiceHoursPlural);
            appendDecimalUnit(builder, MessageFormat.format(template, Map.of("n", hours)), hours, 0, "hour");
        }
        if (minutes > 0) {
            String template = context.getResources().getString(R.string.voiceMinutesPlural);
            appendDecimalUnit(builder, MessageFormat.format(template, Map.of("n", minutes)), minutes, 0, "minute");
        }
        if (seconds > 0 || duration.isZero()) {
            String template = context.getResources().getString(R.string.voiceSecondsPlural);
            appendDecimalUnit(builder, MessageFormat.format(template, Map.of("n", seconds)), seconds, 0, "second");
        }
    }

    private static void appendTime(@NonNull SpannableStringBuilder builder, OffsetDateTime now) {
        TtsSpan.TimeBuilder ttsSpan = new TtsSpan.TimeBuilder();
        ttsSpan.setHours(now.getHour());
        ttsSpan.setMinutes(now.getMinute());

        String formattedTime = DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT)
                        .format(now);

        Spannable spannable = new SpannableString(formattedTime + ".");
        spannable.setSpan(ttsSpan.build(), 0, spannable.length(), SPAN_INCLUSIVE_EXCLUSIVE);
        builder.append(spannable);
        builder.append(" ");
    }

    /**
     * Speaks as: 98.14 [UNIT] - ninety eight point one four [UNIT with correct plural form]
     *
     * @param number The number to speak
     * @param precision The number of decimal places to announce
     */
    private static void appendDecimalUnit(@NonNull SpannableStringBuilder builder, @NonNull String localizedText, double number, int precision, @NonNull String unit) {
        TtsSpan.MeasureBuilder measureBuilder = new TtsSpan.MeasureBuilder()
                .setUnit(unit);

        // Round before extracting integral and decimal parts
        double roundedNumber = Math.round(Math.pow(10, precision) * number) / Math.pow(10.0, precision);
        long integerPart = (long) roundedNumber;

        if (precision == 0 || (roundedNumber - integerPart) == 0) {
            measureBuilder.setNumber((long)number);
        } else {
            // Extract the decimal part
            String fractionalPart = String.format("%." + precision + "f", (roundedNumber - integerPart)).substring(2);
            measureBuilder.setIntegerPart(integerPart)
                    .setFractionalPart(fractionalPart);
        }

        builder.append(" ")
                .append(localizedText, measureBuilder.build(), SPAN_INCLUSIVE_EXCLUSIVE);
    }

    /**
     * Speaks as: 98 - ninety eight
     */
    private static void appendCardinal(@NonNull SpannableStringBuilder builder, @NonNull String localizedText, long number) {
        builder.append(" ")
                .append(localizedText, new TtsSpan.CardinalBuilder().setNumber(number).build(), SPAN_INCLUSIVE_EXCLUSIVE);
    }
}