import { Ionicons } from "@expo/vector-icons";
import { router } from "expo-router";
import { useCallback, useEffect, useState } from "react";
import {
  ActivityIndicator,
  FlatList,
  KeyboardAvoidingView,
  Modal,
  Platform,
  Pressable,
  StyleSheet,
  Text,
  TextInput,
  View,
} from "react-native";
import { useSafeAreaInsets } from "react-native-safe-area-context";
import { useSocket } from "@/contexts/SocketContext";
import { createFolder, listFolders } from "@/lib/api";
import { colors, monoFont } from "@/lib/theme";
import type { FolderEntry, FolderListResult } from "@/lib/types";

function FolderRow({
  item,
  isLast,
  onPress,
}: {
  item: FolderEntry;
  isLast: boolean;
  onPress: () => void;
}) {
  return (
    <Pressable
      style={({ pressed }) => [styles.row, pressed && styles.rowPressed]}
      onPress={onPress}
    >
      <View style={styles.rowIcon}>
        <Ionicons name="folder-outline" size={18} color={colors.accent} />
      </View>
      <View style={[styles.rowMain, !isLast && styles.rowDivider]}>
        <Text style={styles.folderName} numberOfLines={1}>
          {item.name}
        </Text>
        <Ionicons name="chevron-forward" size={16} color={colors.textMuted} />
      </View>
    </Pressable>
  );
}

function NewFolderModal({
  visible,
  name,
  creating,
  error,
  onChangeName,
  onCancel,
  onCreate,
}: {
  visible: boolean;
  name: string;
  creating: boolean;
  error: string | null;
  onChangeName: (value: string) => void;
  onCancel: () => void;
  onCreate: () => void;
}) {
  return (
    <Modal visible={visible} animationType="fade" transparent onRequestClose={onCancel}>
      <KeyboardAvoidingView
        style={styles.modalOverlay}
        behavior={Platform.OS === "ios" ? "padding" : undefined}
      >
        <View style={styles.modalCard}>
          <Text style={styles.modalTitle}>New folder</Text>
          <TextInput
            value={name}
            onChangeText={onChangeName}
            placeholder="Folder name"
            placeholderTextColor={colors.textMuted}
            autoCapitalize="none"
            autoCorrect={false}
            autoFocus
            style={styles.modalInput}
            onSubmitEditing={onCreate}
          />
          {error ? <Text style={styles.modalError}>{error}</Text> : null}
          <View style={styles.modalActions}>
            <Pressable
              style={({ pressed }) => [styles.modalButton, pressed && styles.pressedDim]}
              onPress={onCancel}
              disabled={creating}
            >
              <Text style={styles.modalButtonText}>Cancel</Text>
            </Pressable>
            <Pressable
              style={({ pressed }) => [
                styles.modalButton,
                styles.modalButtonPrimary,
                (creating || !name.trim()) && styles.useButtonDisabled,
                pressed && !creating && styles.pressedDim,
              ]}
              onPress={onCreate}
              disabled={creating || !name.trim()}
            >
              {creating ? (
                <ActivityIndicator color={colors.userBubbleText} size="small" />
              ) : (
                <Text style={styles.modalButtonTextPrimary}>Create</Text>
              )}
            </Pressable>
          </View>
        </View>
      </KeyboardAvoidingView>
    </Modal>
  );
}

function EmptyFolders() {
  return (
    <View style={styles.empty}>
      <View style={styles.emptyIcon}>
        <Ionicons name="folder-open-outline" size={22} color={colors.textMuted} />
      </View>
      <Text style={styles.emptyTitle}>No folders here</Text>
      <Text style={styles.emptyHint}>This directory has no subfolders to browse.</Text>
    </View>
  );
}

function NoSearchResults({ query }: { query: string }) {
  return (
    <View style={styles.empty}>
      <View style={styles.emptyIcon}>
        <Ionicons name="search-outline" size={22} color={colors.textMuted} />
      </View>
      <Text style={styles.emptyTitle}>No matches</Text>
      <Text style={styles.emptyHint}>No folders match "{query}".</Text>
    </View>
  );
}

export default function FolderPickerScreen() {
  const { baseUrl, addProject, savedProjects, error } = useSocket();
  const insets = useSafeAreaInsets();
  const [current, setCurrent] = useState<FolderListResult | null>(null);
  const [loading, setLoading] = useState(true);
  const [adding, setAdding] = useState(false);
  const [localError, setLocalError] = useState<string | null>(null);
  const [newFolderVisible, setNewFolderVisible] = useState(false);
  const [newFolderName, setNewFolderName] = useState("");
  const [creatingFolder, setCreatingFolder] = useState(false);
  const [newFolderError, setNewFolderError] = useState<string | null>(null);
  const [search, setSearch] = useState("");

  const loadPath = useCallback(
    async (path = "~") => {
      if (!baseUrl) {
        return;
      }

      setLoading(true);
      setLocalError(null);
      setSearch("");
      try {
        const result = (await listFolders(baseUrl, path)) as FolderListResult;
        setCurrent(result);
      } catch (loadError) {
        const message = loadError instanceof Error ? loadError.message : "Failed to load folders";
        setLocalError(message);
      } finally {
        setLoading(false);
      }
    },
    [baseUrl],
  );

  useEffect(() => {
    void loadPath("~");
  }, [loadPath]);

  const useFolder = async () => {
    if (!current) {
      return;
    }

    setAdding(true);
    setLocalError(null);
    try {
      await addProject(current.path);
      router.replace({ pathname: "/project", params: { cwd: current.path } });
    } catch (addError) {
      const message =
        addError instanceof Error ? addError.message : "Failed to add project";
      setLocalError(message);
      setAdding(false);
    }
  };

  const openNewFolder = () => {
    setNewFolderName("");
    setNewFolderError(null);
    setNewFolderVisible(true);
  };

  const closeNewFolder = () => {
    if (creatingFolder) {
      return;
    }
    setNewFolderVisible(false);
  };

  const submitNewFolder = async () => {
    const trimmed = newFolderName.trim();
    if (!trimmed || !current || !baseUrl) {
      return;
    }

    setCreatingFolder(true);
    setNewFolderError(null);
    try {
      await createFolder(baseUrl, current.path, trimmed);
      setNewFolderVisible(false);
      await loadPath(current.path);
    } catch (createError) {
      const message =
        createError instanceof Error ? createError.message : "Failed to create folder";
      setNewFolderError(message);
    } finally {
      setCreatingFolder(false);
    }
  };

  const alreadyAdded = current ? savedProjects.includes(current.path) : false;
  const entries = current?.entries ?? [];
  const folderCount = entries.length;
  const trimmedSearch = search.trim().toLowerCase();
  const filteredEntries = trimmedSearch
    ? entries.filter((item) => item.name.toLowerCase().includes(trimmedSearch))
    : entries;

  if (!baseUrl) {
    return (
      <View style={styles.center}>
        <View style={styles.emptyIcon}>
          <Ionicons name="cloud-offline-outline" size={22} color={colors.textMuted} />
        </View>
        <Text style={styles.emptyTitle}>Not connected</Text>
        <Text style={styles.emptyHint}>Connect to a host first.</Text>
      </View>
    );
  }

  return (
    <View style={styles.container}>
      <View style={styles.header}>
        <View style={styles.pathCard}>
          <View style={styles.pathRow}>
            {current?.parent ? (
              <Pressable
                style={({ pressed }) => [styles.upButton, pressed && styles.pressedDim]}
                onPress={() => void loadPath(current.parent ?? "~")}
                hitSlop={6}
              >
                <Ionicons name="chevron-back" size={18} color={colors.accent} />
              </Pressable>
            ) : (
              <View style={styles.upButtonDisabled}>
                <Ionicons name="chevron-back" size={18} color={colors.textMuted} />
              </View>
            )}
            <Ionicons name="folder-outline" size={14} color={colors.textMuted} />
            <Text style={styles.path} numberOfLines={2}>
              {current?.path ?? "~"}
            </Text>
          </View>

          {!loading ? (
            <View style={styles.pathMetaRow}>
              <Text style={styles.pathMeta}>
                {folderCount === 0
                  ? "No subfolders"
                  : `${folderCount} folder${folderCount === 1 ? "" : "s"}`}
              </Text>
              <Pressable
                style={({ pressed }) => [styles.newFolderButton, pressed && styles.pressedDim]}
                onPress={openNewFolder}
                hitSlop={6}
              >
                <Ionicons name="add" size={14} color={colors.accent} />
                <Text style={styles.newFolderButtonText}>New folder</Text>
              </Pressable>
            </View>
          ) : null}
        </View>

        {!loading && folderCount > 0 ? (
          <View style={styles.searchBar}>
            <Ionicons name="search-outline" size={16} color={colors.textMuted} />
            <TextInput
              value={search}
              onChangeText={setSearch}
              placeholder="Search folders"
              placeholderTextColor={colors.textMuted}
              autoCapitalize="none"
              autoCorrect={false}
              style={styles.searchInput}
              returnKeyType="search"
              clearButtonMode="while-editing"
            />
            {Platform.OS !== "ios" && search ? (
              <Pressable onPress={() => setSearch("")} hitSlop={6}>
                <Ionicons name="close-circle" size={16} color={colors.textMuted} />
              </Pressable>
            ) : null}
          </View>
        ) : null}
      </View>

      {loading ? (
        <View style={styles.center}>
          <ActivityIndicator color={colors.text} />
        </View>
      ) : folderCount === 0 ? (
        <EmptyFolders />
      ) : filteredEntries.length === 0 ? (
        <NoSearchResults query={search.trim()} />
      ) : (
        <FlatList
          data={filteredEntries}
          keyExtractor={(item) => item.path}
          style={styles.listScroll}
          contentContainerStyle={styles.list}
          keyboardShouldPersistTaps="handled"
          renderItem={({ item, index }) => (
            <FolderRow
              item={item}
              isLast={index === filteredEntries.length - 1}
              onPress={() => void loadPath(item.path)}
            />
          )}
        />
      )}

      <View style={[styles.footer, { paddingBottom: Math.max(insets.bottom, 16) }]}>
        {localError || error ? (
          <View style={styles.errorBanner}>
            <Ionicons name="alert-circle-outline" size={16} color={colors.errorMuted} />
            <Text style={styles.errorText}>{localError ?? error}</Text>
          </View>
        ) : null}

        <Pressable
          style={({ pressed }) => [
            styles.useButton,
            (adding || !current) && styles.useButtonDisabled,
            pressed && !adding && styles.pressedDim,
          ]}
          disabled={adding || !current}
          onPress={() => void useFolder()}
        >
          {adding ? (
            <ActivityIndicator color={colors.userBubbleText} />
          ) : (
            <>
              <Ionicons
                name={alreadyAdded ? "open-outline" : "add-circle-outline"}
                size={20}
                color={colors.userBubbleText}
              />
              <Text style={styles.useButtonText}>
                {alreadyAdded ? "Open project" : "Add this folder"}
              </Text>
            </>
          )}
        </Pressable>
      </View>

      <NewFolderModal
        visible={newFolderVisible}
        name={newFolderName}
        creating={creatingFolder}
        error={newFolderError}
        onChangeName={setNewFolderName}
        onCancel={closeNewFolder}
        onCreate={() => void submitNewFolder()}
      />
    </View>
  );
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
  },
  header: {
    paddingHorizontal: 16,
    paddingTop: 8,
    paddingBottom: 4,
    gap: 10,
  },
  searchBar: {
    flexDirection: "row",
    alignItems: "center",
    gap: 8,
    backgroundColor: colors.surface,
    borderRadius: 12,
    borderWidth: 1,
    borderColor: colors.borderSubtle,
    paddingHorizontal: 12,
    height: 40,
  },
  searchInput: {
    flex: 1,
    color: colors.text,
    fontSize: 15,
    height: "100%",
  },
  pathCard: {
    backgroundColor: colors.surface,
    borderRadius: 16,
    borderWidth: 1,
    borderColor: colors.borderSubtle,
    padding: 14,
    gap: 10,
  },
  upButton: {
    width: 28,
    height: 28,
    alignItems: "center",
    justifyContent: "center",
    backgroundColor: "rgba(147, 197, 253, 0.1)",
    borderRadius: 8,
  },
  upButtonDisabled: {
    width: 28,
    height: 28,
    alignItems: "center",
    justifyContent: "center",
    opacity: 0.4,
  },
  pathRow: {
    flexDirection: "row",
    alignItems: "center",
    gap: 8,
  },
  path: {
    flex: 1,
    color: colors.textSecondary,
    fontSize: 13,
    lineHeight: 18,
    fontFamily: monoFont,
  },
  pathMetaRow: {
    flexDirection: "row",
    alignItems: "center",
    justifyContent: "space-between",
  },
  pathMeta: {
    color: colors.textMuted,
    fontSize: 12,
    fontFamily: monoFont,
  },
  newFolderButton: {
    flexDirection: "row",
    alignItems: "center",
    gap: 3,
    backgroundColor: "rgba(147, 197, 253, 0.1)",
    borderRadius: 8,
    paddingHorizontal: 9,
    paddingVertical: 5,
  },
  newFolderButtonText: {
    color: colors.accent,
    fontSize: 12,
    fontWeight: "600",
  },
  listScroll: {
    flex: 1,
  },
  list: {
    margin: 16,
    marginBottom: 8,
    backgroundColor: colors.surface,
    borderRadius: 16,
    borderWidth: 1,
    borderColor: colors.borderSubtle,
    overflow: "hidden",
  },
  row: {
    flexDirection: "row",
    alignItems: "center",
    gap: 12,
    paddingLeft: 14,
  },
  rowPressed: {
    backgroundColor: colors.surfaceDeep,
  },
  rowIcon: {
    width: 34,
    height: 34,
    borderRadius: 9,
    backgroundColor: "rgba(147, 197, 253, 0.1)",
    alignItems: "center",
    justifyContent: "center",
  },
  rowMain: {
    flex: 1,
    flexDirection: "row",
    alignItems: "center",
    gap: 8,
    paddingVertical: 13,
    paddingRight: 14,
  },
  rowDivider: {
    borderBottomWidth: StyleSheet.hairlineWidth,
    borderBottomColor: colors.border,
  },
  folderName: {
    flex: 1,
    color: colors.text,
    fontSize: 16,
    fontWeight: "600",
  },
  footer: {
    paddingHorizontal: 16,
    paddingTop: 8,
    gap: 10,
    borderTopWidth: StyleSheet.hairlineWidth,
    borderTopColor: colors.borderSubtle,
    backgroundColor: colors.background,
  },
  useButton: {
    flexDirection: "row",
    alignItems: "center",
    justifyContent: "center",
    gap: 8,
    backgroundColor: colors.userBubbleBg,
    borderRadius: 14,
    minHeight: 52,
  },
  useButtonDisabled: {
    opacity: 0.6,
  },
  useButtonText: {
    color: colors.userBubbleText,
    fontWeight: "700",
    fontSize: 16,
  },
  pressedDim: {
    opacity: 0.7,
  },
  center: {
    flex: 1,
    alignItems: "center",
    justifyContent: "center",
    gap: 6,
    padding: 32,
  },
  empty: {
    flex: 1,
    alignItems: "center",
    justifyContent: "center",
    gap: 6,
    padding: 32,
  },
  emptyIcon: {
    width: 48,
    height: 48,
    borderRadius: 24,
    backgroundColor: colors.surfaceDeep,
    borderWidth: 1,
    borderColor: colors.border,
    alignItems: "center",
    justifyContent: "center",
    marginBottom: 4,
  },
  emptyTitle: {
    color: colors.text,
    fontSize: 15,
    fontWeight: "600",
  },
  emptyHint: {
    color: colors.textMuted,
    fontSize: 13,
    lineHeight: 19,
    textAlign: "center",
    maxWidth: 260,
  },
  errorBanner: {
    flexDirection: "row",
    alignItems: "center",
    gap: 8,
    backgroundColor: "#450a0a",
    borderRadius: 10,
    paddingHorizontal: 12,
    paddingVertical: 10,
  },
  errorText: {
    flex: 1,
    color: colors.errorMuted,
    fontSize: 13,
    lineHeight: 18,
  },
  modalOverlay: {
    flex: 1,
    backgroundColor: "rgba(0, 0, 0, 0.6)",
    alignItems: "center",
    justifyContent: "center",
    padding: 24,
  },
  modalCard: {
    width: "100%",
    maxWidth: 340,
    backgroundColor: colors.surface,
    borderRadius: 16,
    borderWidth: 1,
    borderColor: colors.borderSubtle,
    padding: 18,
    gap: 12,
  },
  modalTitle: {
    color: colors.text,
    fontSize: 16,
    fontWeight: "700",
  },
  modalInput: {
    backgroundColor: colors.surfaceDeep,
    borderRadius: 10,
    borderWidth: 1,
    borderColor: colors.border,
    color: colors.text,
    fontSize: 15,
    paddingHorizontal: 12,
    paddingVertical: 10,
  },
  modalError: {
    color: colors.errorMuted,
    fontSize: 13,
    lineHeight: 18,
  },
  modalActions: {
    flexDirection: "row",
    gap: 10,
  },
  modalButton: {
    flex: 1,
    alignItems: "center",
    justifyContent: "center",
    minHeight: 44,
    borderRadius: 12,
    borderWidth: 1,
    borderColor: colors.border,
  },
  modalButtonPrimary: {
    backgroundColor: colors.userBubbleBg,
    borderColor: colors.userBubbleBg,
  },
  modalButtonText: {
    color: colors.text,
    fontSize: 15,
    fontWeight: "600",
  },
  modalButtonTextPrimary: {
    color: colors.userBubbleText,
    fontSize: 15,
    fontWeight: "700",
  },
});