import { View, Text } from 'react-native';
import { Ionicons } from '@expo/vector-icons';
import { useTranslation } from 'react-i18next';
import { useColors } from '../../lib/theme';
import { HalfDonut } from '../common/HalfDonut';
import { CooldownPatternAnalysis } from './CooldownPatternAnalysis';
import type { BackendCooldownEntry } from '../../hooks/useProfileData';
import type { ProtectionCoverageData } from '../../hooks/useProfileData';

export type CooldownEntry = {
  id: string;
  startedAt: string;
  rawStartedAt: string;
  durationLabel: string;
  status: 'active' | 'resolved' | 'cancelled';
  reason: string | null;
};

type Props = {
  coverage: ProtectionCoverageData | null;
  cooldowns: CooldownEntry[];
  rawCooldowns: BackendCooldownEntry[] | null;
};

const WEEKS = 8;
const MAX_BAR_HEIGHT = 28;
const MIN_BAR_HEIGHT = 2;
const DONUT_WIDTH = 180;
const PROTECTED_COLOR = '#22c55e';
const UNPROTECTED_COLOR = '#e5e5e5';

function getMondayOfWeek(date: Date): Date {
  const d = new Date(date);
  const day = d.getDay();
  const diff = (day === 0 ? -6 : 1 - day);
  d.setDate(d.getDate() + diff);
  d.setHours(0, 0, 0, 0);
  return d;
}

function buildWeekBuckets(cooldowns: CooldownEntry[]): number[] {
  const now = new Date();
  const currentWeekMonday = getMondayOfWeek(now);

  const buckets: number[] = Array(WEEKS).fill(0);

  for (const c of cooldowns) {
    if (!c.rawStartedAt) continue;
    const started = new Date(c.rawStartedAt);
    const weekMonday = getMondayOfWeek(started);
    const diffMs = currentWeekMonday.getTime() - weekMonday.getTime();
    const diffWeeks = Math.round(diffMs / (7 * 24 * 60 * 60 * 1000));
    if (diffWeeks >= 0 && diffWeeks < WEEKS) {
      const bucketIndex = WEEKS - 1 - diffWeeks;
      buckets[bucketIndex]++;
    }
  }

  return buckets;
}

function formatLastDate(cooldowns: CooldownEntry[], language: string): string {
  if (cooldowns.length === 0) return '';
  const sorted = [...cooldowns].sort(
    (a, b) => new Date(b.rawStartedAt).getTime() - new Date(a.rawStartedAt).getTime(),
  );
  const latest = new Date(sorted[0].rawStartedAt);
  if (language === 'de') {
    const day = String(latest.getDate()).padStart(2, '0');
    const month = String(latest.getMonth() + 1).padStart(2, '0');
    return `${day}.${month}.`;
  }
  return latest.toLocaleDateString('en-US', { month: 'short', day: 'numeric' });
}

function formatAvg(totalCount: number, language: string): string {
  if (totalCount === 0) return '0';
  const avg = WEEKS / totalCount;
  if (language === 'de') {
    return avg.toFixed(1).replace('.', ',');
  }
  return avg.toFixed(1);
}

export function StreakSection({ coverage, cooldowns, rawCooldowns }: Props) {
  const colors = useColors();
  const { t, i18n } = useTranslation();
  const lang = i18n.language ?? 'de';

  const buckets = buildWeekBuckets(cooldowns);
  const maxCount = Math.max(...buckets, 1);
  const totalInWindow = buckets.reduce((s, v) => s + v, 0);
  const cooldownsInWindow = totalInWindow;

  const lastDate = cooldowns.length > 0 ? formatLastDate(cooldowns, lang) : null;
  const avgStr = formatAvg(cooldownsInWindow, lang);

  const countLabel =
    cooldownsInWindow === 0
      ? t('profile.cooldown.none')
      : cooldownsInWindow === 1
      ? t('profile.cooldown.count_one', { weeks: WEEKS })
      : t('profile.cooldown.count_other', { n: cooldownsInWindow, weeks: WEEKS });

  const avgLabel =
    cooldownsInWindow > 0 && lastDate
      ? t('profile.cooldown.avg_last', { avg: avgStr, date: lastDate })
      : null;

  const hasData = coverage !== null && coverage.firstProtectionAt !== null;

  const donutSegments = hasData
    ? [
        { value: Math.max(coverage!.protectedDays, 1), color: PROTECTED_COLOR },
        { value: Math.max(coverage!.unprotectedDays, 0), color: UNPROTECTED_COLOR },
      ]
    : [{ value: 1, color: UNPROTECTED_COLOR }];

  const current = coverage?.currentStreakDays ?? 0;
  const record = coverage?.longestStreakDays ?? 0;
  const progressRatio = record > 0 ? Math.min(current / record, 1) : 1;
  const isNewRecord = current >= record && record > 0;
  const isFirstPhase = record === 0;

  let streakLabel: string;
  if (isFirstPhase) {
    streakLabel = t('profile.streak_first_phase', { days: current });
  } else if (isNewRecord) {
    streakLabel = t('profile.streak_new_record', { days: current });
  } else {
    streakLabel = t('profile.streak_to_record', { days: record - current });
  }

  return (
    <View style={{ marginHorizontal: 16, marginTop: 24 }}>
      <View
        style={{
          flexDirection: 'row',
          alignItems: 'center',
          gap: 8,
          marginBottom: 10,
        }}
      >
        <Ionicons name="shield-checkmark-outline" size={14} color={colors.textMuted} />
        <Text
          style={{
            fontSize: 11,
            color: colors.textMuted,
            fontFamily: 'Nunito_700Bold',
            letterSpacing: 0.8,
          }}
        >
          {t('profile.streak_section_label')}
        </Text>
      </View>

      <View
        style={{
          backgroundColor: colors.card,
          borderWidth: 1,
          borderColor: colors.border,
          borderRadius: 14,
          padding: 16,
        }}
      >
        {hasData ? (
          <>
            <View
              style={{
                flexDirection: 'row',
                alignItems: 'flex-end',
                gap: 20,
              }}
            >
              <HalfDonut
                segments={donutSegments}
                centerValue={coverage!.protectedDays}
                centerLabel={t('profile.coverage_center_label')}
                width={DONUT_WIDTH}
              />
              <View style={{ flex: 1, gap: 8, paddingBottom: 8 }}>
                <View style={{ flexDirection: 'row', alignItems: 'center', gap: 6 }}>
                  <View style={{ width: 8, height: 8, borderRadius: 4, backgroundColor: PROTECTED_COLOR }} />
                  <Text style={{ fontSize: 12, fontFamily: 'Nunito_600SemiBold', color: colors.text }}>
                    {coverage!.protectedDays} {t('profile.streak_days_protected')}
                  </Text>
                </View>
                <View style={{ flexDirection: 'row', alignItems: 'center', gap: 6 }}>
                  <View style={{ width: 8, height: 8, borderRadius: 4, backgroundColor: UNPROTECTED_COLOR, borderWidth: 1, borderColor: colors.border }} />
                  <Text style={{ fontSize: 12, fontFamily: 'Nunito_400Regular', color: colors.textMuted }}>
                    {coverage!.unprotectedDays} {t('profile.coverage_unprotected_label')}
                  </Text>
                </View>
              </View>
            </View>

            <View style={{ marginTop: 16 }}>
              <View
                style={{
                  flexDirection: 'row',
                  alignItems: 'center',
                  gap: 8,
                  marginBottom: 8,
                }}
              >
                <Ionicons name="flame-outline" size={13} color={colors.textMuted} />
                <Text
                  style={{
                    fontSize: 11,
                    color: colors.textMuted,
                    fontFamily: 'Nunito_700Bold',
                    letterSpacing: 0.8,
                  }}
                >
                  {t('profile.streak_phase_label')}
                </Text>
              </View>

              <View
                style={{
                  height: 8,
                  backgroundColor: colors.surfaceElevated,
                  borderRadius: 4,
                  overflow: 'hidden',
                }}
              >
                <View
                  style={{
                    height: 8,
                    width: `${Math.round(progressRatio * 100)}%`,
                    backgroundColor: isNewRecord ? '#f59e0b' : PROTECTED_COLOR,
                    borderRadius: 4,
                  }}
                />
              </View>

              <Text
                style={{
                  marginTop: 6,
                  fontSize: 12,
                  color: isNewRecord ? colors.warning : colors.textMuted,
                  fontFamily: isNewRecord ? 'Nunito_700Bold' : 'Nunito_400Regular',
                }}
              >
                {streakLabel}
              </Text>
            </View>
          </>
        ) : (
          <View style={{ alignItems: 'center', paddingVertical: 12 }}>
            <Ionicons name="shield-outline" size={32} color={colors.border} />
            <Text
              style={{
                marginTop: 8,
                fontSize: 14,
                color: colors.text,
                fontFamily: 'Nunito_600SemiBold',
                textAlign: 'center',
              }}
            >
              {t('profile.coverage_no_data')}
            </Text>
            <Text
              style={{
                marginTop: 4,
                fontSize: 12,
                color: colors.textMuted,
                fontFamily: 'Nunito_400Regular',
                textAlign: 'center',
              }}
            >
              {t('profile.coverage_no_data_hint')}
            </Text>
          </View>
        )}
      </View>

      <View style={{ marginTop: 16 }}>
        <View
          style={{
            flexDirection: 'row',
            alignItems: 'center',
            justifyContent: 'space-between',
            marginBottom: 8,
            paddingHorizontal: 2,
          }}
        >
          <Text
            style={{
              fontSize: 11,
              color: colors.textMuted,
              fontFamily: 'Nunito_700Bold',
              letterSpacing: 0.8,
            }}
          >
            {t('profile.cooldown.heading')}
          </Text>
          <Text
            style={{
              fontSize: 11,
              color: colors.textMuted,
              fontFamily: 'Nunito_400Regular',
            }}
          >
            {t('profile.cooldown.window_label', { weeks: WEEKS })}
          </Text>
        </View>

        <View
          style={{
            backgroundColor: colors.card,
            borderWidth: 1,
            borderColor: colors.border,
            borderRadius: 14,
            padding: 16,
          }}
        >
          <View
            style={{
              flexDirection: 'row',
              alignItems: 'flex-end',
              justifyContent: 'space-between',
              height: MAX_BAR_HEIGHT + 20,
              marginBottom: 6,
            }}
          >
            {buckets.map((count, i) => {
              const isEmpty = count === 0;
              const barHeight = isEmpty
                ? MIN_BAR_HEIGHT
                : Math.max(
                    MIN_BAR_HEIGHT,
                    Math.min(count, 5) / Math.min(maxCount, 5) * MAX_BAR_HEIGHT,
                  );
              return (
                <View key={i} style={{ alignItems: 'center', flex: 1 }}>
                  <View
                    style={{
                      width: 10,
                      height: barHeight,
                      borderRadius: 3,
                      backgroundColor: isEmpty ? colors.border : colors.brandOrange,
                    }}
                  />
                </View>
              );
            })}
          </View>

          <View
            style={{
              flexDirection: 'row',
              justifyContent: 'space-between',
              marginBottom: 12,
            }}
          >
            {buckets.map((_, i) => (
              <View key={i} style={{ flex: 1, alignItems: 'center' }}>
                <Text
                  style={{
                    fontSize: 9,
                    color: colors.textMuted,
                    fontFamily: 'Nunito_400Regular',
                  }}
                >
                  {t('profile.cooldown.week_label', { n: i + 1 })}
                </Text>
              </View>
            ))}
          </View>

          <Text
            style={{
              fontSize: 12,
              color: colors.text,
              fontFamily: 'Nunito_600SemiBold',
            }}
          >
            {countLabel}
          </Text>

          {avgLabel ? (
            <Text
              style={{
                marginTop: 2,
                fontSize: 12,
                color: colors.textMuted,
                fontFamily: 'Nunito_400Regular',
              }}
            >
              {avgLabel}
            </Text>
          ) : null}
        </View>

        <CooldownPatternAnalysis rawCooldowns={rawCooldowns} />
      </View>
    </View>
  );
}
