import { Feather } from "@expo/vector-icons";
import axios from "axios";
import * as Haptics from "expo-haptics";
import React, { useEffect, useState } from "react";
import {
  ActivityIndicator,
  Alert,
  Platform,
  ScrollView,
  StyleSheet,
  Text,
  TextInput,
  TouchableOpacity,
  View,
} from "react-native";
import { KeyboardAwareScrollView } from "react-native-keyboard-controller";
import { useSafeAreaInsets } from "react-native-safe-area-context";
import { usePostiz, DEFAULT_BASE_URL } from "@/context/PostizContext";
import { useColors } from "@/hooks/useColors";
import { extractError } from "@/lib/extractError";

export default function SettingsScreen() {
  const colors = useColors();
  const insets = useSafeAreaInsets();
  const { apiKey, baseUrl, isConfigured, saveSettings, clearSettings } = usePostiz();

  const [inputKey, setInputKey] = useState(apiKey);
  const [inputUrl, setInputUrl] = useState(baseUrl || DEFAULT_BASE_URL);
  const [showKey, setShowKey] = useState(false);
  const [validating, setValidating] = useState(false);
  const [saving, setSaving] = useState(false);
  const [validationStatus, setValidationStatus] = useState<"idle" | "ok" | "error">("idle");
  const [errorDetail, setErrorDetail] = useState<string>("");

  useEffect(() => {
    setInputKey(apiKey);
    setInputUrl(baseUrl || DEFAULT_BASE_URL);
  }, [apiKey, baseUrl]);

  const handleValidate = async () => {
    if (!inputKey.trim() || !inputUrl.trim()) {
      Alert.alert("Missing fields", "Please enter both API key and base URL.");
      return;
    }
    setValidating(true);
    setValidationStatus("idle");
    setErrorDetail("");
    const cleanUrl = inputUrl.trim().replace(/\/$/, "");

    const authVariants = [
      inputKey.trim(),
      `Bearer ${inputKey.trim()}`,
    ];

    let lastError: string = "";

    for (const authHeader of authVariants) {
      try {
        await axios.get(`${cleanUrl}/integrations`, {
          headers: { Authorization: authHeader },
          timeout: 10000,
          maxRedirects: 0,
        });
        setValidationStatus("ok");
        Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
        setValidating(false);
        return;
      } catch (err: unknown) {
        if (axios.isAxiosError(err)) {
          const status = err.response?.status;
          if (status === 307 || status === 301 || status === 302 || status === 308) {
            const location = err.response?.headers?.location ?? "unknown";
            lastError = `HTTP ${status} redirect → ${location}. The API rejected the request and redirected to login. Check the Authorization header format or the base URL.`;
            continue;
          }
          if (status === 401 || status === 403) {
            lastError = `HTTP ${status}: Invalid or expired API key.`;
            continue;
          }
        }
        lastError = extractError(err);
      }
    }

    setErrorDetail(lastError);
    setValidationStatus("error");
    Haptics.notificationAsync(Haptics.NotificationFeedbackType.Error);
    setValidating(false);
  };

  const handleSave = async () => {
    if (!inputKey.trim() || !inputUrl.trim()) {
      Alert.alert("Missing fields", "Please enter both API key and base URL.");
      return;
    }
    setSaving(true);
    try {
      await saveSettings(inputKey.trim(), inputUrl.trim().replace(/\/$/, ""));
      Haptics.notificationAsync(Haptics.NotificationFeedbackType.Success);
      Alert.alert("Saved", "Settings saved successfully.");
    } catch (err: unknown) {
      Alert.alert("Error", `Failed to save settings.\n${extractError(err)}`);
    } finally {
      setSaving(false);
    }
  };

  const handleClear = () => {
    Alert.alert(
      "Disconnect",
      "Remove your API key and disconnect from Postiz?",
      [
        { text: "Cancel", style: "cancel" },
        {
          text: "Disconnect",
          style: "destructive",
          onPress: async () => {
            await clearSettings();
            setInputKey("");
            setInputUrl(DEFAULT_BASE_URL);
            setValidationStatus("idle");
            setErrorDetail("");
          },
        },
      ]
    );
  };

  return (
    <KeyboardAwareScrollView
      style={{ flex: 1, backgroundColor: colors.background }}
      contentContainerStyle={[
        styles.container,
        {
          paddingTop: Platform.OS === "web" ? 67 : 24,
          paddingBottom: Platform.OS === "web" ? 100 : insets.bottom + 40,
        },
      ]}
      bottomOffset={60}
      keyboardShouldPersistTaps="handled"
      showsVerticalScrollIndicator={false}
    >
      {!isConfigured && (
        <View style={[styles.banner, { backgroundColor: colors.primary + "18", borderColor: colors.primary + "40" }]}>
          <Feather name="info" size={16} color={colors.primary} />
          <Text style={[styles.bannerText, { color: colors.primary }]}>
            Connect to your Postiz instance to get started
          </Text>
        </View>
      )}

      {isConfigured && (
        <View style={[styles.connectedBadge, { backgroundColor: colors.success + "18", borderColor: colors.success + "40" }]}>
          <Feather name="check-circle" size={14} color={colors.success} />
          <Text style={[styles.connectedText, { color: colors.success }]}>
            Connected to Postiz
          </Text>
        </View>
      )}

      <View style={styles.section}>
        <Text style={[styles.label, { color: colors.mutedForeground }]}>BASE URL</Text>
        <View style={[styles.inputWrap, { backgroundColor: colors.card, borderColor: colors.border }]}>
          <Feather name="globe" size={16} color={colors.mutedForeground} style={styles.inputIcon} />
          <TextInput
            style={[styles.input, { color: colors.foreground }]}
            placeholder="https://postiz.example.com/api/public/v1"
            placeholderTextColor={colors.mutedForeground}
            value={inputUrl}
            onChangeText={(t) => { setInputUrl(t); setValidationStatus("idle"); setErrorDetail(""); }}
            autoCapitalize="none"
            autoCorrect={false}
            keyboardType="url"
          />
        </View>
      </View>

      <View style={styles.section}>
        <Text style={[styles.label, { color: colors.mutedForeground }]}>API KEY</Text>
        <View style={[styles.inputWrap, { backgroundColor: colors.card, borderColor: colors.border }]}>
          <Feather name="key" size={16} color={colors.mutedForeground} style={styles.inputIcon} />
          <TextInput
            style={[styles.input, { color: colors.foreground }]}
            placeholder="Enter your API key"
            placeholderTextColor={colors.mutedForeground}
            value={inputKey}
            onChangeText={(t) => { setInputKey(t); setValidationStatus("idle"); setErrorDetail(""); }}
            secureTextEntry={!showKey}
            autoCapitalize="none"
            autoCorrect={false}
          />
          <TouchableOpacity onPress={() => setShowKey((v) => !v)} activeOpacity={0.7}>
            <Feather name={showKey ? "eye-off" : "eye"} size={16} color={colors.mutedForeground} />
          </TouchableOpacity>
        </View>

        {validationStatus === "ok" && (
          <View style={styles.validationRow}>
            <Feather name="check-circle" size={13} color={colors.success} />
            <Text style={[styles.validationText, { color: colors.success }]}>
              Connection successful
            </Text>
          </View>
        )}

        {validationStatus === "error" && (
          <View style={[styles.errorBox, { backgroundColor: colors.error + "12", borderColor: colors.error + "30" }]}>
            <View style={styles.errorHeader}>
              <Feather name="x-circle" size={13} color={colors.error} />
              <Text style={[styles.errorTitle, { color: colors.error }]}>
                Could not connect
              </Text>
            </View>
            {!!errorDetail && (
              <ScrollView style={styles.errorScroll} nestedScrollEnabled>
                <Text style={[styles.errorDetail, { color: colors.error }]} selectable>
                  {errorDetail}
                </Text>
              </ScrollView>
            )}
          </View>
        )}
      </View>

      <TouchableOpacity
        onPress={handleValidate}
        activeOpacity={0.8}
        disabled={validating}
        style={[styles.validateBtn, { backgroundColor: colors.card, borderColor: colors.border }]}
      >
        {validating ? (
          <ActivityIndicator color={colors.primary} size="small" />
        ) : (
          <>
            <Feather name="wifi" size={15} color={colors.primary} />
            <Text style={[styles.validateText, { color: colors.primary }]}>
              Test Connection
            </Text>
          </>
        )}
      </TouchableOpacity>

      <TouchableOpacity
        onPress={handleSave}
        activeOpacity={0.85}
        disabled={saving}
        style={[styles.saveBtn, { backgroundColor: saving ? colors.muted : colors.primary }]}
      >
        {saving ? (
          <ActivityIndicator color={colors.primaryForeground} size="small" />
        ) : (
          <>
            <Feather name="save" size={15} color={colors.primaryForeground} />
            <Text style={[styles.saveText, { color: colors.primaryForeground }]}>
              Save Settings
            </Text>
          </>
        )}
      </TouchableOpacity>

      {isConfigured && (
        <TouchableOpacity
          onPress={handleClear}
          activeOpacity={0.8}
          style={[styles.clearBtn, { borderColor: colors.destructive + "60" }]}
        >
          <Feather name="log-out" size={14} color={colors.destructive} />
          <Text style={[styles.clearText, { color: colors.destructive }]}>Disconnect</Text>
        </TouchableOpacity>
      )}

      <View style={styles.footer}>
        <Text style={[styles.footerText, { color: colors.mutedForeground }]}>
          Your API key is stored securely on this device and never transmitted to third parties.
        </Text>
      </View>
    </KeyboardAwareScrollView>
  );
}

const styles = StyleSheet.create({
  container: {
    paddingHorizontal: 20,
    gap: 16,
  },
  banner: {
    flexDirection: "row",
    alignItems: "center",
    gap: 10,
    paddingHorizontal: 14,
    paddingVertical: 12,
    borderRadius: 12,
    borderWidth: 1,
  },
  bannerText: {
    fontSize: 13,
    fontFamily: "Inter_500Medium",
    flex: 1,
  },
  connectedBadge: {
    flexDirection: "row",
    alignItems: "center",
    gap: 6,
    paddingHorizontal: 12,
    paddingVertical: 8,
    borderRadius: 10,
    borderWidth: 1,
    alignSelf: "flex-start",
  },
  connectedText: {
    fontSize: 12,
    fontFamily: "Inter_600SemiBold",
  },
  section: {
    gap: 8,
  },
  label: {
    fontSize: 11,
    fontFamily: "Inter_600SemiBold",
    letterSpacing: 0.8,
    marginLeft: 2,
  },
  inputWrap: {
    flexDirection: "row",
    alignItems: "center",
    borderRadius: 12,
    borderWidth: 1,
    paddingHorizontal: 14,
    paddingVertical: 12,
    gap: 10,
  },
  inputIcon: {
    flexShrink: 0,
  },
  input: {
    flex: 1,
    fontSize: 14,
    fontFamily: "Inter_400Regular",
  },
  validationRow: {
    flexDirection: "row",
    alignItems: "center",
    gap: 6,
    marginLeft: 2,
  },
  validationText: {
    fontSize: 12,
    fontFamily: "Inter_400Regular",
  },
  errorBox: {
    borderRadius: 10,
    borderWidth: 1,
    padding: 12,
    gap: 6,
  },
  errorHeader: {
    flexDirection: "row",
    alignItems: "center",
    gap: 6,
  },
  errorTitle: {
    fontSize: 12,
    fontFamily: "Inter_600SemiBold",
  },
  errorScroll: {
    maxHeight: 80,
  },
  errorDetail: {
    fontSize: 11,
    fontFamily: "Inter_400Regular",
    lineHeight: 16,
  },
  validateBtn: {
    flexDirection: "row",
    alignItems: "center",
    justifyContent: "center",
    gap: 8,
    paddingVertical: 12,
    borderRadius: 12,
    borderWidth: 1,
  },
  validateText: {
    fontSize: 14,
    fontFamily: "Inter_600SemiBold",
  },
  saveBtn: {
    flexDirection: "row",
    alignItems: "center",
    justifyContent: "center",
    gap: 8,
    paddingVertical: 14,
    borderRadius: 14,
  },
  saveText: {
    fontSize: 15,
    fontFamily: "Inter_600SemiBold",
  },
  clearBtn: {
    flexDirection: "row",
    alignItems: "center",
    justifyContent: "center",
    gap: 8,
    paddingVertical: 12,
    borderRadius: 12,
    borderWidth: 1,
  },
  clearText: {
    fontSize: 14,
    fontFamily: "Inter_500Medium",
  },
  footer: {
    marginTop: 8,
  },
  footerText: {
    fontSize: 12,
    fontFamily: "Inter_400Regular",
    textAlign: "center",
    lineHeight: 18,
  },
});