import { Ionicons } from "@expo/vector-icons";
import { router, useLocalSearchParams } from "expo-router";
import { useMemo, useState } from "react";
import { Alert, Image, ScrollView, View } from "react-native";
import {
  RxImagePager,
  RxMedicineLines,
  RxQueriedPanel,
  RxStatusStepper,
} from "@/components/prescription";
import { EscalationBanner } from "@/components/care";
import { Badge } from "@/components/ui/Badge";
import { Button } from "@/components/ui/Button";
import { Card, InfoRow, Section } from "@/components/ui/Card";
import { DoseReminderPanel } from "@/components/ui/DoseReminderPanel";
import { AppHeader } from "@/components/ui/Header";
import { Screen } from "@/components/ui/Screen";
import { Text } from "@/components/ui/Text";
import { products } from "@/lib/data/products";
import { scheduleDoseReminder } from "@/lib/notifications";
import { routes } from "@/lib/routes";
import { useCartStore } from "@/lib/stores/cartStore";
import { useNotificationStore } from "@/lib/stores/notificationStore";
import { usePrescriptionStore } from "@/lib/stores/prescriptionStore";
import { colors, gutter } from "@/lib/theme";

const statusTone = {
  submitted: "neutral",
  under_review: "warn",
  approved: "brand",
  queried: "info",
  rejected: "danger",
  filled: "brand",
} as const;

export default function PrescriptionDetailScreen() {
  const params = useLocalSearchParams<{ id: string }>();
  const id = Array.isArray(params.id) ? params.id[0] : params.id;
  const rx = usePrescriptionStore((s) => s.prescriptions.find((p) => p.id === id));
  const allReminders = usePrescriptionStore((s) => s.reminders);
  const doseLogs = usePrescriptionStore((s) => s.doseLogs);
  const reminders = useMemo(
    () => allReminders.filter((r) => r.prescriptionId === id),
    [allReminders, id]
  );
  const reminder = reminders[0];
  const reminderId = `rem_${id}`;
  const recentLogs = useMemo(
    () => doseLogs.filter((l) => l.reminderId === reminderId).slice(0, 5),
    [doseLogs, reminderId]
  );
  const markRefilled = usePrescriptionStore((s) => s.markRefilled);
  const updateRxStatus = usePrescriptionStore((s) => s.updateRxStatus);
  const replyToQuery = usePrescriptionStore((s) => s.replyToQuery);
  const confirmDose = usePrescriptionStore((s) => s.confirmDose);
  const addProduct = useCartStore((s) => s.addProduct);
  const pushNotification = useNotificationStore((s) => s.push);
  const [showSetup, setShowSetup] = useState(!reminder?.enabled);

  if (!rx) {
    return (
      <Screen>
        <AppHeader title="Prescription" />
        <View style={{ padding: gutter }}>
          <Text variant="body" color={colors.muted}>
            Prescription not found.
          </Text>
        </View>
      </Screen>
    );
  }

  const dueIn = (() => {
    if (!rx.lastFilledAt) return null;
    const due = new Date(rx.lastFilledAt);
    due.setDate(due.getDate() + rx.daysSupply);
    return Math.ceil((due.getTime() - Date.now()) / (1000 * 60 * 60 * 24));
  })();

  const pendingLog = recentLogs.find((l) => l.status === "pending");
  const refillSoon = dueIn !== null && dueIn <= 5;

  return (
    <Screen>
      <AppHeader
        title="Prescription"
        subtitle={rx.patientName}
        right={<Badge label={rx.status.replace("_", " ")} tone={statusTone[rx.status]} />}
      />
      <ScrollView
        contentContainerStyle={{
          paddingHorizontal: gutter,
          paddingBottom: 40,
          gap: 14,
        }}
      >
        <Card elevated={false}>
          <Text variant="label" color={colors.muted} style={{ marginBottom: 12 }}>
            Pharmacist review status
          </Text>
          <RxStatusStepper status={rx.status} />
        </Card>

        {rx.status === "queried" ? (
          <RxQueriedPanel
            pharmacistMessage={rx.pharmacistMessage}
            customerReply={rx.customerReply}
            onReply={(message) => {
              replyToQuery(rx.id, message);
              pushNotification({
                kind: "rx",
                title: "Reply sent",
                body: "Your clarification was sent back to the pharmacist.",
                href: routes.rxDetail(rx.id),
              });
              Alert.alert("Sent", "Status moved back to under review.");
            }}
          />
        ) : null}

        {rx.status === "rejected" ? (
          <Card tone="wash" elevated={false} style={{ borderColor: colors.danger }}>
            <Text variant="h3" color={colors.danger}>
              Prescription rejected
            </Text>
            <Text variant="bodySm" color={colors.muted} style={{ marginTop: 6 }}>
              {rx.pharmacistMessage ||
                "The pharmacist could not approve this script. Upload a clearer copy or visit a branch."}
            </Text>
            <Button
              title="Scan new prescription"
              style={{ marginTop: 12 }}
              onPress={() => router.push(routes.rxScan)}
            />
          </Card>
        ) : null}

        {refillSoon ? (
          <Card tone="brand" elevated={false}>
            <Text variant="h3">
              {dueIn !== null && dueIn <= 0 ? "Refill overdue" : "Refill reminder"}
            </Text>
            <Text variant="bodySm" color={colors.muted} style={{ marginTop: 6 }}>
              {dueIn !== null && dueIn <= 0
                ? "Days of supply have run out — reorder or mark refilled after pickup."
                : `About ${dueIn} day${dueIn === 1 ? "" : "s"} of supply left.`}
            </Text>
            <Button
              title="One-tap refill to cart"
              style={{ marginTop: 12 }}
              icon="bag-add-outline"
              onPress={() => {
                rx.medicines.forEach((m) => {
                  const match = products.find((p) =>
                    p.name.toLowerCase().includes(m.name.toLowerCase().split(" ")[0])
                  );
                  if (match) addProduct(match);
                });
                router.push(routes.cart);
              }}
            />
          </Card>
        ) : null}

        <Card elevated style={{ padding: 0, overflow: "hidden" }}>
          <View
            style={{
              height: 160,
              backgroundColor: colors.brandSoft,
              alignItems: "center",
              justifyContent: "center",
            }}
          >
            {rx.imageUris[0] ? (
              <Image
                source={{ uri: rx.imageUris[0] }}
                style={{ width: "100%", height: "100%" }}
                resizeMode="cover"
              />
            ) : (
              <Ionicons name="document-text" size={48} color={colors.brandText} />
            )}
          </View>
          <View style={{ padding: 16, gap: 10 }}>
            <Text variant="h1">{rx.medicineName}</Text>
            <Text variant="bodySm" color={colors.muted}>
              For {rx.patientName} · {rx.medicines.length} item
              {rx.medicines.length === 1 ? "" : "s"} on this Rx
            </Text>
            {rx.imageUris.length > 1 ? (
              <View style={{ marginTop: 4 }}>
                <Text variant="caption" color={colors.subtle} style={{ marginBottom: 8 }}>
                  Pages
                </Text>
                <RxImagePager uris={rx.imageUris} size={72} />
              </View>
            ) : null}
            <View style={{ flexDirection: "row", flexWrap: "wrap", gap: 8 }}>
              <Badge label={`${rx.daysSupply} day supply`} tone="neutral" icon="time-outline" />
              {dueIn !== null ? (
                <Badge
                  label={dueIn <= 0 ? "Refill overdue" : `Refill in ${dueIn} days`}
                  tone={dueIn <= 3 ? "warn" : "brand"}
                />
              ) : (
                <Badge label="Awaiting first fill" tone="warn" />
              )}
              {reminder?.enabled ? (
                <Badge label={reminder.times.join(" · ")} tone="brand" icon="alarm-outline" />
              ) : (
                <Badge label="Reminders off" tone="neutral" icon="alarm-outline" />
              )}
            </View>
          </View>
        </Card>

        <Section title="Dose calendar & push">
          {reminder?.escalateOnMiss ? (
            <View style={{ marginBottom: 10 }}>
              <EscalationBanner />
            </View>
          ) : null}
          <Card>
            {reminder?.enabled && !showSetup ? (
              <View style={{ gap: 12 }}>
                <View style={{ flexDirection: "row", alignItems: "center", gap: 10 }}>
                  <View
                    style={{
                      width: 44,
                      height: 44,
                      borderRadius: 14,
                      backgroundColor: colors.brandSoft,
                      alignItems: "center",
                      justifyContent: "center",
                    }}
                  >
                    <Ionicons name="notifications" size={20} color={colors.brandText} />
                  </View>
                  <View style={{ flex: 1 }}>
                    <Text variant="h3">Daily reminders on</Text>
                    <Text variant="caption" color={colors.muted} style={{ marginTop: 2 }}>
                      Push at {reminder.times.join(" · ")}
                      {reminder.escalateOnMiss ? " · escalate if missed" : ""}
                    </Text>
                  </View>
                </View>
                <View style={{ flexDirection: "row", flexWrap: "wrap", gap: 8 }}>
                  <Button
                    title="Edit times"
                    size="md"
                    fullWidth={false}
                    variant="outline"
                    onPress={() => setShowSetup(true)}
                  />
                  <Button
                    title="Open calendar"
                    size="md"
                    fullWidth={false}
                    icon="calendar-outline"
                    onPress={() => router.push(routes.rxCalendar(rx.id))}
                  />
                  <Button
                    title="Test push now"
                    size="md"
                    fullWidth={false}
                    variant="soft"
                    icon="flash-outline"
                    onPress={async () => {
                      await scheduleDoseReminder({
                        title: `Time for ${rx.medicineName}`,
                        body: "Test dose reminder from Gishen",
                        secondsFromNow: 5,
                        data: { prescriptionId: rx.id, type: "dose" },
                      });
                      pushNotification({
                        kind: "dose",
                        title: "Test dose reminder",
                        body: `${rx.medicineName} push scheduled in ~5s`,
                        href: routes.rxDetail(rx.id),
                      });
                      Alert.alert("Scheduled", "Test push in about 5 seconds.");
                    }}
                  />
                </View>
              </View>
            ) : (
              <DoseReminderPanel
                rx={rx}
                reminder={reminder}
                onScheduled={() => setShowSetup(false)}
              />
            )}
          </Card>

          {pendingLog ? (
            <Card tone="brand" elevated={false} style={{ marginTop: 10 }}>
              <Text variant="h3">Confirm today’s dose</Text>
              <Text variant="bodySm" color={colors.muted} style={{ marginTop: 4 }}>
                A dose is pending confirmation.
              </Text>
              <View style={{ flexDirection: "row", gap: 10, marginTop: 12 }}>
                <Button
                  title="Taken"
                  style={{ flex: 1 }}
                  onPress={() => {
                    confirmDose(pendingLog.id);
                    Alert.alert("Logged", "Dose marked as taken.");
                  }}
                />
                <Button
                  title="Snooze 10m"
                  variant="outline"
                  style={{ flex: 1 }}
                  onPress={() =>
                    scheduleDoseReminder({
                      title: `Snoozed: ${rx.medicineName}`,
                      body: "Take your dose when ready",
                      secondsFromNow: 600,
                      data: { prescriptionId: rx.id, type: "dose" },
                    })
                  }
                />
              </View>
            </Card>
          ) : null}

          {recentLogs.length ? (
            <View style={{ marginTop: 12, gap: 8 }}>
              <Text variant="label" color={colors.muted}>
                Recent dose logs
              </Text>
              {recentLogs.map((l) => (
                <View
                  key={l.id}
                  style={{
                    flexDirection: "row",
                    alignItems: "center",
                    gap: 10,
                    paddingVertical: 8,
                    borderBottomWidth: 1,
                    borderBottomColor: colors.line,
                  }}
                >
                  <Badge
                    label={l.status.replace("_", " ")}
                    tone={
                      l.status === "taken"
                        ? "brand"
                        : l.status === "missed_escalated"
                          ? "danger"
                          : "warn"
                    }
                  />
                  <Text variant="caption" color={colors.subtle} style={{ flex: 1 }}>
                    {new Date(l.scheduledAt).toLocaleString()}
                  </Text>
                </View>
              ))}
            </View>
          ) : null}
        </Section>

        <Section title="Medicines on this Rx">
          <RxMedicineLines medicines={rx.medicines} />
        </Section>

        <Section title="Details">
          <Card elevated={false}>
            <InfoRow label="Days supply" value={`${rx.daysSupply} days`} />
            <InfoRow
              label="Last filled"
              value={
                rx.lastFilledAt
                  ? new Date(rx.lastFilledAt).toLocaleDateString()
                  : "Not filled yet"
              }
            />
            <InfoRow
              label="Submitted"
              value={new Date(rx.createdAt).toLocaleDateString()}
              last={!rx.notes}
            />
            {rx.notes ? <InfoRow label="Notes" value={rx.notes} last /> : null}
          </Card>
        </Section>

        <View style={{ gap: 10 }}>
          <Button
            title="Reorder medicines"
            icon="bag-add-outline"
            onPress={() => {
              rx.medicines.forEach((m) => {
                const match = products.find((p) =>
                  p.name.toLowerCase().includes(m.name.toLowerCase().split(" ")[0])
                );
                if (match) addProduct(match);
              });
              router.push(routes.cart);
            }}
          />
          <Button
            title="Mark as refilled"
            variant="outline"
            onPress={() => {
              markRefilled(rx.id);
              Alert.alert("Updated", "Marked as refilled today.");
            }}
          />
          {rx.status === "under_review" || rx.status === "submitted" ? (
            <Button
              title="Simulate pharmacist approval"
              variant="soft"
              onPress={() => updateRxStatus(rx.id, "approved")}
            />
          ) : null}
          {rx.status === "submitted" ? (
            <Button
              title="Simulate pharmacist query"
              variant="ghost"
              onPress={() =>
                updateRxStatus(
                  rx.id,
                  "queried",
                  "Please confirm the prescribed strength on page 1."
                )
              }
            />
          ) : null}
        </View>
      </ScrollView>
    </Screen>
  );
}