import React, { useState, useEffect } from "react";
import { View, Text, StyleSheet, ActivityIndicator } from "react-native";
import { LinearGradient } from "expo-linear-gradient";
import { Ionicons } from "@expo/vector-icons";
import { theme } from "../styles/theme";
import { useStatistics } from "../contexts/StatisticsContext";
import type { WeeklyTrendData } from "../api/types";
import log from "../utils/logger";

export function WeeklyProgressWidget() {
  const { statistics, loading, refetchStatistics } = useStatistics();
  const [weeklyData, setWeeklyData] = useState<WeeklyTrendData[]>([]);

  useEffect(() => {
    refetchStatistics();
  }, [refetchStatistics]);

  useEffect(() => {
    if (statistics?.weeklyTrend) {
      log.debug("WeeklyProgressWidget - Processing weekly trend", {
        weeklyTrendLength: statistics.weeklyTrend.length,
        weeklyTrend: statistics.weeklyTrend,
        statisticsKeys: Object.keys(statistics),
      });

      // Get last 4 weeks for compact display
      const last4Weeks = statistics.weeklyTrend.slice(-4);
      setWeeklyData(last4Weeks);

      log.debug("WeeklyProgressWidget - Set weekly data", {
        last4Weeks,
      });
    } else {
      log.debug("WeeklyProgressWidget - No weekly trend data", {
        hasStatistics: !!statistics,
        statistics,
      });
    }
  }, [statistics]);

  if (loading) {
    return (
      <View style={styles.container}>
        <ActivityIndicator size="small" color={theme.colors.primary} />
      </View>
    );
  }

  if (weeklyData.length === 0) {
    return null;
  }

  // Calculate totals from last 4 weeks
  const totalCheckIns = weeklyData.reduce(
    (sum, week) => sum + week.checkIns,
    0,
  );
  const totalGoals = weeklyData.reduce(
    (sum, week) => sum + week.goalsCompleted,
    0,
  );
  const avgProgress =
    weeklyData.reduce((sum, week) => sum + week.averageProgress, 0) /
    weeklyData.length;

  // Get max value for scaling bars
  const maxCheckIns = Math.max(...weeklyData.map((w) => w.checkIns), 1);

  return (
    <View style={styles.container}>
      <LinearGradient
        colors={theme.gradients.purple}
        start={{ x: 0, y: 0 }}
        end={{ x: 1, y: 1 }}
        style={styles.card}
      >
        <View style={styles.header}>
          <View>
            <Text style={styles.title}>Weekly Progress</Text>
            <Text style={styles.subtitle}>Last 4 weeks</Text>
          </View>
          <View style={styles.iconContainer}>
            <Ionicons name="trending-up" size={24} color="#fff" />
          </View>
        </View>

        <View style={styles.statsRow}>
          <View style={styles.statItem}>
            <Text style={styles.statValue}>{totalCheckIns}</Text>
            <Text style={styles.statLabel}>Check-ins</Text>
          </View>
          <View style={styles.statDivider} />
          <View style={styles.statItem}>
            <Text style={styles.statValue}>{totalGoals}</Text>
            <Text style={styles.statLabel}>Goals Met</Text>
          </View>
          <View style={styles.statDivider} />
          <View style={styles.statItem}>
            <Text style={styles.statValue}>{Math.round(avgProgress)}%</Text>
            <Text style={styles.statLabel}>Avg Progress</Text>
          </View>
        </View>

        <View style={styles.chartContainer}>
          {weeklyData.map((week, index) => {
            const barHeight = (week.checkIns / maxCheckIns) * 60;
            return (
              <View key={index} style={styles.barContainer}>
                <View style={styles.barWrapper}>
                  <View
                    style={[styles.bar, { height: Math.max(barHeight, 4) }]}
                  />
                </View>
                <Text style={styles.barLabel}>{week.weekLabel}</Text>
              </View>
            );
          })}
        </View>
      </LinearGradient>
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    paddingHorizontal: 20,
    marginBottom: 16,
  },
  card: {
    borderRadius: theme.borderRadius["2xl"],
    padding: 20,
    ...theme.shadows.medium,
  },
  header: {
    flexDirection: "row",
    justifyContent: "space-between",
    alignItems: "flex-start",
    marginBottom: 20,
  },
  title: {
    fontSize: theme.typography.fontSize.xl,
    fontWeight: theme.typography.fontWeight.bold,
    color: theme.colors.white,
    marginBottom: 4,
  },
  subtitle: {
    fontSize: theme.typography.fontSize.sm,
    color: "rgba(255, 255, 255, 0.8)",
  },
  iconContainer: {
    backgroundColor: "rgba(255, 255, 255, 0.2)",
    width: 48,
    height: 48,
    borderRadius: 24,
    justifyContent: "center",
    alignItems: "center",
  },
  statsRow: {
    flexDirection: "row",
    justifyContent: "space-around",
    marginBottom: 20,
    backgroundColor: "rgba(255, 255, 255, 0.15)",
    borderRadius: theme.borderRadius.xl,
    padding: 16,
  },
  statItem: {
    alignItems: "center",
    flex: 1,
  },
  statValue: {
    fontSize: theme.typography.fontSize["2xl"],
    fontWeight: theme.typography.fontWeight.bold,
    color: theme.colors.white,
    marginBottom: 4,
  },
  statLabel: {
    fontSize: theme.typography.fontSize.xs,
    color: "rgba(255, 255, 255, 0.7)",
    textAlign: "center",
  },
  statDivider: {
    width: 1,
    backgroundColor: "rgba(255, 255, 255, 0.2)",
    marginHorizontal: 8,
  },
  chartContainer: {
    flexDirection: "row",
    justifyContent: "space-around",
    alignItems: "flex-end",
    height: 80,
  },
  barContainer: {
    alignItems: "center",
    flex: 1,
  },
  barWrapper: {
    height: 60,
    justifyContent: "flex-end",
    marginBottom: 6,
  },
  bar: {
    width: 24,
    backgroundColor: "rgba(255, 255, 255, 0.9)",
    borderRadius: 4,
    minHeight: 4,
  },
  barLabel: {
    fontSize: 10,
    color: "rgba(255, 255, 255, 0.7)",
    fontWeight: "500",
  },
});