import { useCallback, useState } from "react";
import { Pressable, Text, View, Platform, ScrollView } from "react-native";
import { useRouter } from "expo-router";
import { StyleSheet, useUnistyles } from "react-native-unistyles";
import { QrCode, Link2, ClipboardPaste } from "lucide-react-native";
import { useSafeAreaInsets } from "react-native-safe-area-context";
import type { HostProfile } from "@/types/host-connection";
import { useHostMutations } from "@/runtime/host-runtime";
import { useSessionStore } from "@/stores/session-store";
import { AddHostModal } from "./add-host-modal";
import { PairLinkModal } from "./pair-link-modal";
import { NameHostModal } from "./name-host-modal";
import { resolveAppVersion } from "@/utils/app-version";
import { formatVersionWithPrefix } from "@/desktop/updates/desktop-updates";
import { buildHostRootRoute } from "@/utils/host-routes";
import { PaseoLogo } from "@/components/icons/paseo-logo";

type WelcomeAction = {
  key: "scan-qr" | "direct-connection" | "paste-pairing-link";
  label: string;
  testID: string;
  primary: boolean;
  icon: typeof QrCode;
  onPress: () => void;
};

const styles = StyleSheet.create((theme) => ({
  container: {
    flexGrow: 1,
    backgroundColor: theme.colors.surface0,
    padding: theme.spacing[6],
    paddingBottom: 0,
    alignItems: "center",
  },
  content: {
    width: "100%",
    flexGrow: 1,
    justifyContent: "center",
    alignItems: "center",
  },
  title: {
    color: theme.colors.foreground,
    fontSize: theme.fontSize.xl,
    fontWeight: theme.fontWeight.medium,
    marginBottom: theme.spacing[3],
    textAlign: "center",
  },
  subtitle: {
    color: theme.colors.foregroundMuted,
    fontSize: theme.fontSize.base,
    textAlign: "center",
    marginBottom: theme.spacing[8],
  },
  actions: {
    width: "100%",
    maxWidth: 420,
    gap: theme.spacing[3],
  },
  actionButton: {
    flexDirection: "row",
    alignItems: "center",
    justifyContent: "center",
    gap: theme.spacing[3],
    paddingVertical: theme.spacing[4],
    borderRadius: theme.borderRadius.xl,
    backgroundColor: theme.colors.surface2,
    borderWidth: 1,
    borderColor: theme.colors.border,
  },
  actionButtonPrimary: {
    backgroundColor: theme.colors.accent,
    borderColor: theme.colors.accent,
  },
  actionText: {
    color: theme.colors.foreground,
    fontSize: theme.fontSize.base,
    fontWeight: theme.fontWeight.medium,
  },
  actionTextPrimary: {
    color: theme.colors.accentForeground,
  },
  versionLabel: {
    color: theme.colors.foregroundMuted,
    fontSize: theme.fontSize.xs,
    textAlign: "center",
    marginTop: theme.spacing[6],
  },
}));

export interface WelcomeScreenProps {
  onHostAdded?: (profile: HostProfile) => void;
}

export function WelcomeScreen({ onHostAdded }: WelcomeScreenProps) {
  const { theme } = useUnistyles();
  const insets = useSafeAreaInsets();
  const router = useRouter();
  const { renameHost } = useHostMutations();
  const appVersion = resolveAppVersion();
  const appVersionText = formatVersionWithPrefix(appVersion);
  const [isDirectOpen, setIsDirectOpen] = useState(false);
  const [isPasteLinkOpen, setIsPasteLinkOpen] = useState(false);
  const [pendingNameHost, setPendingNameHost] = useState<{ serverId: string; hostname: string | null } | null>(null);
  const [pendingRedirectServerId, setPendingRedirectServerId] = useState<string | null>(null);
  const pendingNameHostname = useSessionStore(
    useCallback(
      (state) => {
        if (!pendingNameHost) return null;
        return state.sessions[pendingNameHost.serverId]?.serverInfo?.hostname ?? pendingNameHost.hostname ?? null;
      },
      [pendingNameHost]
    )
  );

  const finishOnboarding = useCallback(
    (serverId: string) => {
      router.replace(buildHostRootRoute(serverId) as any);
    },
    [router]
  );

  const actions: WelcomeAction[] = Platform.OS === "web"
    ? [
        {
          key: "direct-connection",
          label: "Direct connection",
          testID: "welcome-direct-connection",
          primary: true,
          icon: Link2,
          onPress: () => setIsDirectOpen(true),
        },
        {
          key: "paste-pairing-link",
          label: "Paste pairing link",
          testID: "welcome-paste-pairing-link",
          primary: false,
          icon: ClipboardPaste,
          onPress: () => setIsPasteLinkOpen(true),
        },
      ]
    : [
        {
          key: "scan-qr",
          label: "Scan QR code",
          testID: "welcome-scan-qr",
          primary: true,
          icon: QrCode,
          onPress: () => router.push("/pair-scan?source=onboarding"),
        },
        {
          key: "direct-connection",
          label: "Direct connection",
          testID: "welcome-direct-connection",
          primary: false,
          icon: Link2,
          onPress: () => setIsDirectOpen(true),
        },
        {
          key: "paste-pairing-link",
          label: "Paste pairing link",
          testID: "welcome-paste-pairing-link",
          primary: false,
          icon: ClipboardPaste,
          onPress: () => setIsPasteLinkOpen(true),
        },
      ];

  return (
    <ScrollView
      style={{ flex: 1, backgroundColor: theme.colors.surface0 }}
      contentContainerStyle={[
        styles.container,
        { paddingBottom: theme.spacing[6] + insets.bottom },
      ]}
      showsVerticalScrollIndicator={false}
      testID="welcome-screen"
    >
      <View style={styles.content}>
        <PaseoLogo size={96} color={theme.colors.foreground} />
        <Text style={styles.title}>Welcome to Paseo</Text>
        <Text style={styles.subtitle}>Connect to your host to start</Text>

        <View style={styles.actions}>
          {actions.map((action) => {
            const Icon = action.icon;
            return (
            <Pressable
              key={action.key}
              style={[styles.actionButton, action.primary ? styles.actionButtonPrimary : null]}
              onPress={action.onPress}
              testID={action.testID}
            >
              <Icon
                size={18}
                color={action.primary ? theme.colors.accentForeground : theme.colors.foreground}
              />
              <Text style={[styles.actionText, action.primary ? styles.actionTextPrimary : null]}>
                {action.label}
              </Text>
            </Pressable>
            );
          })}
        </View>
      </View>
      <Text style={styles.versionLabel}>{appVersionText}</Text>

      <AddHostModal
        visible={isDirectOpen}
        onClose={() => setIsDirectOpen(false)}
        onSaved={({ profile, serverId, hostname, isNewHost }) => {
          onHostAdded?.(profile);
          setPendingRedirectServerId(serverId);
          if (isNewHost) {
            setPendingNameHost({ serverId, hostname });
            return;
          }
          finishOnboarding(serverId);
        }}
      />

      <PairLinkModal
        visible={isPasteLinkOpen}
        onClose={() => setIsPasteLinkOpen(false)}
        onSaved={({ profile, serverId, hostname, isNewHost }) => {
          onHostAdded?.(profile);
          setPendingRedirectServerId(serverId);
          if (isNewHost) {
            setPendingNameHost({ serverId, hostname });
            return;
          }
          finishOnboarding(serverId);
        }}
      />

      {pendingNameHost && pendingRedirectServerId ? (
        <NameHostModal
          visible
          serverId={pendingNameHost.serverId}
          hostname={pendingNameHostname}
          onSkip={() => {
            const serverId = pendingRedirectServerId;
            setPendingNameHost(null);
            setPendingRedirectServerId(null);
            finishOnboarding(serverId);
          }}
          onSave={(label) => {
            const serverId = pendingRedirectServerId;
            void renameHost(pendingNameHost.serverId, label).finally(() => {
              setPendingNameHost(null);
              setPendingRedirectServerId(null);
              finishOnboarding(serverId);
            });
          }}
        />
      ) : null}
    </ScrollView>
  );
}