import { useLocalSearchParams } from "expo-router";
import { useMemo, useState } from "react";
import { Alert, ScrollView, View } from "react-native";
import { Badge } from "@/components/ui/Badge";
import { Button } from "@/components/ui/Button";
import { Card } from "@/components/ui/Card";
import { Chip } from "@/components/ui/Chip";
import { Field, SwitchRow } from "@/components/ui/Field";
import { AppHeader } from "@/components/ui/Header";
import { EmptyState } from "@/components/ui/EmptyState";
import { Screen } from "@/components/ui/Screen";
import { Text } from "@/components/ui/Text";
import {
  scheduleDoseReminder,
  scheduleEscalationCheck,
} from "@/lib/notifications";
import { useEmergencyContactStore } from "@/lib/stores/emergencyContactStore";
import { usePrescriptionStore } from "@/lib/stores/prescriptionStore";
import { colors, gutter } from "@/lib/theme";

const PRESETS = ["08:00", "12:00", "14:00", "18:00", "20:00"] as const;

export default function RxCalendarScreen() {
  const { id } = useLocalSearchParams<{ id: string }>();
  const rx = usePrescriptionStore((s) => s.prescriptions.find((p) => p.id === id));
  const upsertReminder = usePrescriptionStore((s) => s.upsertReminder);
  const schedulePendingDose = usePrescriptionStore((s) => s.schedulePendingDose);
  const confirmDose = usePrescriptionStore((s) => s.confirmDose);
  const escalateDose = usePrescriptionStore((s) => s.escalateDose);
  const doseLogs = usePrescriptionStore((s) => s.doseLogs);
  const reminder = usePrescriptionStore((s) =>
    s.reminders.find((r) => r.prescriptionId === id)
  );
  const grace = useEmergencyContactStore((s) => s.graceMinutesDefault);
  const setGrace = useEmergencyContactStore((s) => s.setGrace);
  const escalationEnabled = useEmergencyContactStore((s) => s.escalationEnabled);
  const setEscalationEnabled = useEmergencyContactStore((s) => s.setEscalationEnabled);
  const contacts = useEmergencyContactStore((s) => s.contacts);
  const markEscalated = useEmergencyContactStore((s) => s.markEscalated);
  const [times, setTimes] = useState(reminder?.times.join(",") || "08:00,20:00");
  const [pendingLogId, setPendingLogId] = useState<string | null>(null);

  const reminderId = `rem_${id}`;
  const relatedLogs = useMemo(
    () => doseLogs.filter((l) => l.reminderId === reminderId).slice(0, 8),
    [doseLogs, reminderId]
  );

  if (!rx) {
    return (
      <Screen>
        <EmptyState icon="calendar-outline" title="Prescription not found" />
      </Screen>
    );
  }

  const togglePreset = (t: string) => {
    const list = times
      .split(",")
      .map((s) => s.trim())
      .filter(Boolean);
    if (list.includes(t)) {
      setTimes(list.filter((x) => x !== t).join(","));
    } else {
      setTimes([...list, t].sort().join(","));
    }
  };

  const saveAndSchedule = async () => {
    const parsed = times
      .split(",")
      .map((s) => s.trim())
      .filter(Boolean);
    if (!parsed.length) {
      Alert.alert("Times required", "Pick at least one reminder time.");
      return;
    }
    upsertReminder({
      id: reminderId,
      prescriptionId: rx.id,
      medicineName: rx.medicineName,
      times: parsed,
      daysOfWeek: [0, 1, 2, 3, 4, 5, 6],
      graceMinutes: grace,
      escalateOnMiss: escalationEnabled,
      enabled: true,
    });
    await scheduleDoseReminder({
      title: `Time for ${rx.medicineName}`,
      body: "Tap to confirm you took your dose",
      secondsFromNow: 15,
      data: { prescriptionId: rx.id, type: "dose" },
    });
    const log = schedulePendingDose(reminderId);
    setPendingLogId(log.id);

    if (escalationEnabled && contacts.length) {
      await scheduleEscalationCheck({
        title: "Dose not confirmed",
        body: `Notifying ${contacts[0].name} if still unconfirmed`,
        graceSeconds: Math.max(20, grace * 60),
        data: { logId: log.id, type: "escalation" },
      });
      setTimeout(() => {
        const current = usePrescriptionStore
          .getState()
          .doseLogs.find((l) => l.id === log.id);
        if (current?.status === "pending") {
          escalateDose(log.id);
          markEscalated();
          Alert.alert("Emergency", `${contacts[0].name} would be notified (mock SMS/push)`);
        }
      }, Math.max(25000, grace * 1000));
    } else if (escalationEnabled && !contacts.length) {
      Alert.alert(
        "No emergency contact",
        "Add a contact under Profile → Emergency contacts for escalation."
      );
    }

    Alert.alert("Scheduled", `Reminders at ${parsed.join(", ")}. Demo push in ~15s.`);
  };

  return (
    <Screen>
      <AppHeader title="Reminders" subtitle={rx.medicineName} />
      <ScrollView
        contentContainerStyle={{
          paddingHorizontal: gutter,
          paddingBottom: 40,
          gap: 14,
        }}
      >
        <Card>
          <Text variant="caption" color={colors.muted}>
            Patient
          </Text>
          <Text variant="h3" style={{ marginTop: 4 }}>
            {rx.patientName || "Self"}
          </Text>
          <Text variant="bodySm" color={colors.muted} style={{ marginTop: 4 }}>
            {rx.status} · {rx.daysSupply} day supply
          </Text>
        </Card>

        <Card>
          <Text variant="h3">Dose times</Text>
          <Text variant="caption" color={colors.muted} style={{ marginTop: 4 }}>
            Tap presets or edit the comma-separated list
          </Text>
          <View style={{ flexDirection: "row", flexWrap: "wrap", gap: 8, marginTop: 12 }}>
            {PRESETS.map((p) => {
              const selected = times
                .split(",")
                .map((s) => s.trim())
                .includes(p);
              return (
                <Chip
                  key={p}
                  label={p}
                  selected={selected}
                  onPress={() => togglePreset(p)}
                  size="sm"
                />
              );
            })}
          </View>
          <View style={{ marginTop: 12 }}>
            <Field
              label="Times (HH:mm)"
              value={times}
              onChangeText={setTimes}
              hint="Example: 08:00,14:00,20:00"
            />
          </View>
        </Card>

        <Card padded={false}>
          <SwitchRow
            icon="alert-circle-outline"
            title="Escalate if missed"
            subtitle={
              contacts[0]
                ? `Notify ${contacts[0].name} after grace period`
                : "Add an emergency contact first"
            }
            value={escalationEnabled}
            onValueChange={setEscalationEnabled}
          />
          <View style={{ padding: 16, paddingTop: 4 }}>
            <Field
              label="Grace minutes"
              value={String(grace)}
              keyboardType="number-pad"
              onChangeText={(v) => setGrace(Number(v) || 30)}
            />
          </View>
        </Card>

        {pendingLogId ? (
          <Card tone="brand" elevated={false}>
            <Text variant="h3">Confirm this dose</Text>
            <Text variant="bodySm" color={colors.muted} style={{ marginTop: 4 }}>
              Demo reminder is active. Mark taken or snooze.
            </Text>
            <View style={{ flexDirection: "row", gap: 10, marginTop: 14 }}>
              <Button
                title="Taken"
                style={{ flex: 1 }}
                onPress={() => {
                  confirmDose(pendingLogId);
                  setPendingLogId(null);
                  Alert.alert("Logged", "Dose confirmed");
                }}
              />
              <Button
                title="Snooze 10m"
                variant="outline"
                style={{ flex: 1 }}
                onPress={() =>
                  scheduleDoseReminder({
                    title: `Snoozed: ${rx.medicineName}`,
                    body: "Reminder",
                    secondsFromNow: 600,
                  })
                }
              />
            </View>
          </Card>
        ) : null}

        <Button title="Save & schedule push" onPress={saveAndSchedule} />

        <Text variant="h3">Recent dose logs</Text>
        {relatedLogs.length === 0 && doseLogs.length === 0 ? (
          <Text variant="bodySm" color={colors.muted}>
            No logs yet. Schedule a reminder to start tracking.
          </Text>
        ) : (
          (relatedLogs.length ? relatedLogs : doseLogs.slice(0, 8)).map((l) => (
            <Card key={l.id} elevated={false}>
              <View style={{ flexDirection: "row", alignItems: "center", gap: 10 }}>
                <Badge
                  label={l.status.replace("_", " ")}
                  tone={
                    l.status === "taken"
                      ? "brand"
                      : l.status === "missed_escalated"
                        ? "danger"
                        : l.status === "pending"
                          ? "warn"
                          : "neutral"
                  }
                />
                <Text variant="bodySm" color={colors.muted} style={{ flex: 1 }}>
                  {new Date(l.scheduledAt).toLocaleString()}
                </Text>
              </View>
            </Card>
          ))
        )}
      </ScrollView>
    </Screen>
  );
}