import { CometChat } from "@cometchat/chat-sdk-react-native";
import React, { JSX } from "react";
import { ColorValue, StyleProp, Text, TextStyle } from "react-native";
import { CometChatUIKit } from "../../CometChatUiKit";
import {
  MentionsTargetElement,
  MentionsType,
  MentionsVisibility,
} from "../../constants/UIKitConstants";
import { CometChatUIEventHandler, CometChatUIEvents } from "../../events";
import { SuggestionItem } from "../../views/CometChatSuggestionList";
import { CometChatTextFormatter } from "../CometChatTextFormatter";
import { CometChatTheme } from "../../../theme/type";
import { deepMerge } from "../../helper/helperFunctions";
import { getCometChatTranslation } from "../../resources/CometChatLocalizeNew/LocalizationManager";

const t = getCometChatTranslation();

/**
 * Represents the CometChatMentionsFormatter class.
 * This class extends the CometChatTextFormatter class and provides methods for handling mentions in text.
 * @extends CometChatTextFormatter
 */

type MentionsSubStyle = {
  textStyle?: TextStyle;
  selfTextStyle?: TextStyle;
};

type MentionContext = "composer" | "conversation" | "incoming" | "outgoing";

function isCometChatTheme(t: unknown): t is CometChatTheme {
  return (
    !!t &&
    typeof t === "object" &&
    "typography" in t &&
    "color" in t &&
    typeof (t as any).typography === "object" &&
    typeof (t as any).color === "object"
  );
}

export class CometChatMentionsFormatter extends CometChatTextFormatter {
  /**
   * List of users for mentions.
   */
  protected SuggestionItems: Array<SuggestionItem> = [];

  /**
   * List of searched data.
   */
  protected searchData: Array<SuggestionItem> = [];

  /**
   * Stores the formatting style for mentions.
   */
  protected mentionsStyle: CometChatTheme["mentionsStyle"];

  /**
   * Default search request object to fetch users or group members.
   */
  private searchRequest?: CometChat.UsersRequest | CometChat.GroupMembersRequest;

  /**
   * Custom request object to fetch users or group members.
   */
  private customRequest?: CometChat.UsersRequestBuilder | CometChat.GroupMembersRequestBuilder;

  private composerStyle: MentionsSubStyle;
  private conversationStyle: MentionsSubStyle;
  private incomingBubbleStyle: MentionsSubStyle;
  private outgoingBubbleStyle: MentionsSubStyle;
  private currentContext: MentionContext = "incoming";
  private resolveStyle(isSelf: boolean): TextStyle {
    let style: MentionsSubStyle;
    switch (this.currentContext) {
      case "composer":
        style = this.composerStyle;
        break;
      case "conversation":
        style = this.conversationStyle;
        break;
      case "outgoing":
        style = this.outgoingBubbleStyle;
        break;
      default:
        style = this.incomingBubbleStyle;
    }
    return isSelf ? (style.selfTextStyle ?? {}) : (style.textStyle ?? {});
  }

  /**
   * Limit of unique users to be added in the composer.
   */
  protected limit: number = 10;

  /**
   * visibleIn property to determine where the mentions should be visible.
   * @type {MentionsVisibility}
   * @default MentionsVisibility.both
   */
  protected visibleIn: MentionsVisibility = MentionsVisibility.both;

  /**
   * type property to determine the type of mention list.
   * @type {MentionsType}
   * @default MentionsType.usersAndGroupMembers
   */
  protected type: MentionsType = MentionsType.usersAndGroupMembers;

  /**
   * type property to determine the type of mention list.
   * @type {MentionsType}
   * @default MentionsType.usersAndGroupMembers
   */
  protected target: MentionsTargetElement = MentionsTargetElement.textbubble;

  protected textStyle: any = {};

  /**
   * Initializes a new CometChatMentionsFormatter.
   * @param {CometChat.User} loggedInUser - The user who is currently logged in.
   */
  constructor(themeOrUser?: CometChatTheme | CometChat.User, loggedInUser?: CometChat.User) {
    super();
    // Support user mentions <@uid:UID> and group-wide alias mentions <@all:Alias>
    this.regexPattern = /<@(?:uid|all):(.*?)>/g;
    this.trackCharacter = "@";

    const theme = isCometChatTheme(themeOrUser) ? themeOrUser : undefined;
    this.loggedInUser = isCometChatTheme(themeOrUser)
      ? loggedInUser
      : (themeOrUser as CometChat.User | undefined);

    const fallback: MentionsSubStyle = {
      textStyle: { fontWeight: "700", fontSize: 14, lineHeight: 19.6, color: "#6852D6" },
      selfTextStyle: { fontWeight: "700", fontSize: 14, lineHeight: 19.6, color: "#FFAB00" },
    };

    const fromTheme = (c: ColorValue): MentionsSubStyle => {
      const baseStyle = theme?.typography?.body?.bold || {};
      return {
        textStyle: { ...baseStyle, color: c },
        selfTextStyle: { ...baseStyle, color: theme?.color?.warning || "#FFAB00" },
      };
    };

    this.incomingBubbleStyle = theme ? fromTheme(theme.color.receiveBubbleTextHighlight) : fallback;
    this.outgoingBubbleStyle = theme ? fromTheme(theme.color.sendBubbleTextHighlight) : fallback;
    this.composerStyle = this.incomingBubbleStyle; // reasonable defaults
    this.conversationStyle = this.incomingBubbleStyle;
  }

  /** Group-wide alias mention feature */
  private mentionAllLabel: string = "all";
  private disableMentionAll: boolean = false;

  setMentionAllLabel(label: string) {
    if (label && label.trim()) this.mentionAllLabel = label.trim();
    return this;
  }

  setDisableMentionAll(disable: boolean) {
    this.disableMentionAll = !!disable;
    return this;
  }

  getMentionAllLabel() {
    return this.mentionAllLabel;
  }

  isMentionAllDisabled() {
    return this.disableMentionAll;
  }

  private buildGroupMentionItem(): SuggestionItem | null {
    if (this.disableMentionAll) return null;
    if (!this.group) return null; // only relevant inside a group context
    const alias = this.mentionAllLabel || "all";
    return new SuggestionItem({
      id: alias, // id matches regex capture for highlighting
      name: alias,
      promptText: "@" + alias,
      trackingCharacter: "@",
      underlyingText: `<@all:${alias}>`,
      hideLeadingIcon: false,
    });
  }

  /**
   * Sets the message object.
   *
   * @param {CometChat.BaseMessage} messageObject - The message object to be set.
   */
  setMessage(messageObject: CometChat.BaseMessage) {
    this.messageObject = messageObject;

    let mentionedUsers =
      (messageObject?.getMentionedUsers && messageObject?.getMentionedUsers()) || [];
    let cometchatUIUserArray: Array<SuggestionItem> =
      this.convertCCUsersToSuggestionsItem(mentionedUsers);

    // Inject alias mentions present in raw text (incoming/outgoing)
    try {
      const rawText = (messageObject as any)?.getText?.() || "";
      const aliasRegex = /<@all:(.*?)>/g;
      let m: RegExpExecArray | null;
      while ((m = aliasRegex.exec(rawText)) !== null) {
        const alias = m[1];
        if (alias && !cometchatUIUserArray.find((i) => i.underlyingText === `<@all:${alias}>`)) {
          cometchatUIUserArray.push(
            new SuggestionItem({
              id: alias,
              name: alias,
              promptText: "@" + alias,
              trackingCharacter: "@",
              underlyingText: `<@all:${alias}>`,
              hideLeadingIcon: true,
            })
          );
        }
      }
    } catch (e) {
      console.log("🚀 ~ CometChatMentionsFormatter ~ setMessage ~ e:", e);
    }

    this.setSuggestionItems(cometchatUIUserArray);
  }

  setTargetElement(target: MentionsTargetElement) {
    this.target = target;
  }

  setTextStyle(textStyle: any) {
    this.textStyle = textStyle;
  }

  handlePreMessageSend(message: CometChat.TextMessage): CometChat.TextMessage {
    let CCUsers = this.getSuggestionItems()
      .filter((item) => !item.underlyingText.startsWith("<@all:"))
      .map((item) => {
        let user = new CometChat.User(item.id);
        user.setAvatar(item?.leadingIconUrl!);
        user.setName(item?.name!);
        return user;
      });
    if (CCUsers.length) message.setMentionedUsers(CCUsers);
    return message;
  }

  handleComposerPreview(message: CometChat.TextMessage): void {
    const userItems = this.convertCCUsersToSuggestionsItem(message.getMentionedUsers());

    // Preserve any existing @all alias items we discovered in setMessage
    let aliasItems = this.SuggestionItems.filter((item) =>
      item.underlyingText?.startsWith("<@all:")
    );

    // If alias items are missing (common on re-open edit), parse from message text
    try {
      const rawText = message.getText?.() || "";
      const aliasRegex = /<@all:(.*?)>/g;
      let m: RegExpExecArray | null;
      while ((m = aliasRegex.exec(rawText)) !== null) {
        const alias = m[1];
        if (
          alias &&
          !aliasItems.find((i) => i.underlyingText === `<@all:${alias}>`)
        ) {
          const aliasItem = new SuggestionItem({
            id: alias,
            name: alias,
            promptText: "@" + alias,
            trackingCharacter: "@",
            underlyingText: `<@all:${alias}>`,
            hideLeadingIcon: true,
          });
          aliasItems.push(aliasItem);
        }
      }
    } catch (e) {
      console.log("🚀 ~ CometChatMentionsFormatter ~ handleComposerPreview ~ e:", e)
    }

    const merged = [...aliasItems, ...userItems];
    this.setSuggestionItems(merged);
  }

  private convertCCUsersToSuggestionsItem(users: CometChat.User[]) {
    return users.map((item: CometChat.User) => {
      return new SuggestionItem({
        id: item?.getUid(),
        name: item?.getName(),
        promptText: "@" + item?.getName(),
        trackingCharacter: "@",
        underlyingText: `<@uid:${item?.getUid()}>`,
        leadingIconUrl: item?.getAvatar(),
        hideLeadingIcon: false,
      });
    });
  }

  /**
   * Sets the search request builder.
   * @param requestBuilder - The request builder to set.
   */
  setSearchRequestBuilder(
    requestBuilder: CometChat.UsersRequestBuilder | CometChat.GroupMembersRequestBuilder
  ) {
    this.customRequest = requestBuilder;
  }

  private shouldLoadLocalData(searchKey?: string) {
    if (this.getUniqueUsersList().size >= this.limit) {
      let data = searchKey
        ? [...this.SuggestionItems].filter(
            (item) =>
              item.name?.toLowerCase().includes(searchKey.trim().toLowerCase()) ||
              item.id.toLowerCase().includes(searchKey.trim().toLowerCase())
          )
        : [...this.SuggestionItems];
      this.searchData = [...data];
      this.setSearchData(this.searchData);
      return true;
    }
    return false;
  }

  search(searchKey: string): void {
    if (this.shouldLoadLocalData(searchKey)) return;
    let requestBuilder =
      this.customRequest ||
      (this.group && this.type === MentionsType.usersAndGroupMembers
        ? new CometChat.GroupMembersRequestBuilder(this.group.getGuid())
        : new CometChat.UsersRequestBuilder());

    this.searchRequest = requestBuilder.setLimit(10).setSearchKeyword(searchKey).build();
    this.searchData = [];
    // Prepend group-wide alias suggestion if enabled and matches search
    const groupItem = this.buildGroupMentionItem();
    if (groupItem) {
      const include =
        !searchKey || groupItem.name?.toLowerCase().startsWith(searchKey.toLowerCase());
      if (include) this.searchData.push(groupItem);
    }
    this.fetchNext(true);
  }

  fetchNext(freshCall?: boolean): void | null {
    if (this.getUniqueUsersList().size >= this.limit) return;
    this.searchRequest?.fetchNext &&
      this.searchRequest
        ?.fetchNext()
        .then((users: CometChat.User[]) => {
          let structuredData = this.convertCCUsersToSuggestionsItem(users);
          // Preserve any pre-added items (like @all alias) in searchData when freshCall
          this.searchData = freshCall
            ? [...this.searchData, ...structuredData]
            : [...this.searchData, ...structuredData];
          this.setSearchData(this.searchData);
        })
        .catch((err) => {
          console.log("searchRequest fetchNext failed:", err);
          this.setSearchData(this.searchData);
        });
  }

  setSearchData(data: Array<SuggestionItem>) {
    this.searchData = [...data];
    CometChatUIEventHandler.emitUIEvent(CometChatUIEvents.ccSuggestionData, {
      id: this.composerId,
      data: [...this.searchData],
    });
  }

  /**
   * Sets the limit of unique users to be added in the composer.
   */
  setLimit(limit: number) {
    this.limit = limit;
  }

  /**
   * Retrieves the limit of unique users to be added in the composer.
   */
  getLimit() {
    return this.limit;
  }

  /**
   * Retrieves the unique users list.
   */
  getUniqueUsersList(): Set<number | string> {
    // A Set to store unique user IDs
    const uniqueUserIds: Set<number | string> = new Set();

    // Populate the Set with user IDs from the existing user list
    this.SuggestionItems.forEach((item) => {
      if (!item.underlyingText.startsWith("<@all:")) uniqueUserIds.add(item.id);
    });

    return uniqueUserIds;
  }

  /**
   * Retrieves the message object.
   *
   * @returns {CometChat.BaseMessage} - The current message object.
   */
  getMessage(): CometChat.BaseMessage {
    return this.messageObject;
  }

  /**
   * Sets the regex pattern for matching text.
   *
   * @param {<RegExp>} regexPattern - Regex patterns.
   */
  setRegexPattern = (regexPattern: RegExp) => {
    this.regexPattern = regexPattern;
  };

  /**
   * Gets the regex pattern for matching text.
   */
  getRegexPattern = () => {
    return this.regexPattern;
  };

  /**
   * Retrieves the SuggestionItems.
   *
   * @returns {Array<SuggestionItem>} - The current SuggestionItems.
   */
  getSuggestionItems(): Array<SuggestionItem> {
    return this.SuggestionItems;
  }

  /**
   * Sets the SuggestionItems.
   *
   * @param {Array<SuggestionItem>} SuggestionItems - The SuggestionItems to be set.
   */
  setSuggestionItems(SuggestionItems: Array<SuggestionItem>) {
    this.SuggestionItems = [...SuggestionItems];
  }

  /**
   * Retrieves the mentions style.
   *
   * @returns {CometChatTheme["mentionsStyle"]} - The current mentions style.
   */
  getMentionsStyle(): CometChatTheme["mentionsStyle"] {
    return this.mentionsStyle;
  }

  setComposerMentionStyle(s: MentionsSubStyle) {
    this.composerStyle = deepMerge(this.composerStyle, s);
    return this;
  }
  setConversationMentionStyle(s: MentionsSubStyle) {
    this.conversationStyle = deepMerge(this.conversationStyle, s);
    return this;
  }
  setIncomingBubbleMentionStyle(s: MentionsSubStyle) {
    this.incomingBubbleStyle = deepMerge(this.incomingBubbleStyle, s);
    return this;
  }
  setOutgoingBubbleMentionStyle(s: MentionsSubStyle) {
    this.outgoingBubbleStyle = deepMerge(this.outgoingBubbleStyle, s);
    return this;
  }

  /** maintain back-compat */
  setMentionsStyle(patch?: CometChatTheme["mentionsStyle"]) {
    if (!patch) return this;
    const apply = (dst: MentionsSubStyle) => deepMerge(dst, patch);
    this.setIncomingBubbleMentionStyle(apply(this.incomingBubbleStyle))
      .setOutgoingBubbleMentionStyle(apply(this.outgoingBubbleStyle))
      .setComposerMentionStyle(apply(this.composerStyle))
      .setConversationMentionStyle(apply(this.conversationStyle));
    return this;
  }

  /** called from data-sources */
  setContext(ctx: MentionContext) {
    this.currentContext = ctx;
    return this;
  }

  getFormattedText(
    inputText: string | null | JSX.Element,
    textStyle?: StyleProp<TextStyle>
  ): string | JSX.Element {
    if (!inputText) {
      return "";
    }
    let formattedText = this.addMentionsView(inputText, textStyle);
    return formattedText;
  }

  temp!: Function;

  setOnMentionClick(callBack: (message: CometChat.BaseMessage, uid: string) => void) {
    // callBack(this.messageObject, "uid");
    this.temp = callBack;
  }

  /**
   * Emits the event for mention click.
   * @param {any} event - The event object.
   * @param {string} uid - The user id.
   */
  private onMentionClick = (event: any, uid: string) => {
    if (this.temp) {
      this.temp(this.messageObject, uid);
      return;
    }
  };

  /**
   * This function adds the mention view to the input text.
   *
   * @param {string} inputText - The input text where the view needs to be added.
   * @returns {string} - The modified input text.
   */
  protected addMentionsView(
    inputText: string | JSX.Element,
    textStyle: StyleProp<TextStyle> = {}
  ): any {
    if (typeof inputText === "string") {
      let mentions: JSX.Element[] = [];

      if (this.SuggestionItems) {
        const userRegistry: { [key: string]: string } = {};
        const aliasIdSet: Set<string> = new Set();
        for (let i = 0; i < this.SuggestionItems?.length; i++) {
          const item = this.SuggestionItems[i];
          const userUid = item.id;
          const userName = item.promptText;
          userRegistry[userUid] = userName!;
          if (item.underlyingText.startsWith("<@all:")) aliasIdSet.add(userUid);
        }

        // Define the regex pattern
        const regex = this.getRegexPattern();

        // Break the string into segments split by the regex
        let match;
        let lastIndex = 0;
        let segments: any[] = [];

        while ((match = regex.exec(inputText)) !== null) {
          // Add preceding non-UID segment, if any
          if (match.index > lastIndex) {
            segments.push(inputText.slice(lastIndex, match.index));
          }

          // Add UID segment
          segments.push(match[1]);

          // Update lastIndex
          lastIndex = match.index + match[0].length;
        }

        // Append trailing non-UID segment, if any
        if (lastIndex < inputText.length) {
          segments.push(inputText.slice(lastIndex));
        }

        // Now create an array of JSX elements from the segments
        const elements = segments.map((segment, index) => {
          // Check if segment is a UID
          if (userRegistry.hasOwnProperty(segment)) {
            let _loggedInUser = this.loggedInUser || CometChatUIKit.loggedInUser;

            const isAlias = aliasIdSet.has(segment);
            const isSelf = isAlias || _loggedInUser?.getUid() === segment;

            const isOutgoing =
              this.messageObject?.getSender()?.getUid() === _loggedInUser?.getUid();

            if (this.target === MentionsTargetElement.textbubble) {
              this.setContext(isOutgoing ? "outgoing" : "incoming");
            }

            const textStyle = this.resolveStyle(isSelf);

            let onPressProp =
              this.temp && !isAlias
                ? { onPress: (event: any) => this.onMentionClick(event, segment) }
                : {}; // still suppress click for alias

            if (this.target === MentionsTargetElement.textbubble) {
              return (
                <Text suppressHighlighting={true} key={index} {...onPressProp} style={[textStyle]}>
                  {userRegistry[segment]}
                </Text>
              );
            }

            return (
              <Text suppressHighlighting={true} key={index} {...onPressProp} style={[textStyle]}>
                {userRegistry[segment]}
              </Text>
            );
          } else {
            // Handle group-wide alias formatting if present
            const aliasItem = this.SuggestionItems.find(
              (it) => it.underlyingText === `<@all:${segment}>`
            );
            if (aliasItem) {
              const styleResolved = this.resolveStyle(true);
              // If context is 'conversation', render @all and description inline
              if (this.currentContext === "conversation") {
                return (
                  <Text suppressHighlighting={true} key={index} style={[styleResolved]}>
                    <Text style={[styleResolved, { fontWeight: "700" }]}>
                      @{aliasItem.promptText}
                    </Text>
                    <Text style={[styleResolved, { fontWeight: "normal", opacity: 0.7 }]}>
                      {" "}
                      {t("MESSAGE_COMPOSER_MENTION_NOTIFY_EVERYONE_LABEL")}
                    </Text>
                  </Text>
                );
              }
              return (
                <Text suppressHighlighting={true} key={index} style={[styleResolved]}>
                  {aliasItem.promptText}
                </Text>
              );
            }
            if (this.target === MentionsTargetElement.textbubble)
              return (
                <Text key={index} style={{ ...this.textStyle }}>
                  {segment}
                </Text>
              );
            return (
              <Text key={index} style={{ ...this.textStyle }}>
                {segment}
              </Text>
            );
          }
        });

        if (elements.length > 0)
          return <Text style={textStyle}>{elements.map((item) => item)}</Text>;
      }
      return inputText;
    } else if (React.isValidElement(inputText)) {
      // inputText is a React element
      if ((inputText as React.ReactElement<any>).props.children) {
        // If the React element have children, we map over these children
        // and call addMentionsView recursively for each child.
        return React.cloneElement(inputText as React.ReactElement<any>, {
          children: React.Children.map(
            (inputText as React.ReactElement<any>).props.children,
            (child) => {
              return this.addMentionsView(child);
            }
          ),
        });
      } else {
        // If the React element does not have children, return it as is
        return inputText;
      }
    } else {
      throw new Error(`Unsupported inputText type: ${typeof inputText}`);
    }
  }

  /**
   * Sets the type of mention list.
   * @param type - The type of mention list.
   */
  setType(type: MentionsType) {
    this.type = type;
  }

  /**
   * Sets the visibleIn property to determine where the mentions should be visible.
   * @param visibleIn - The visibleIn property to set.
   */
  setVisibleIn(visibleIn: MentionsVisibility) {
    this.visibleIn = visibleIn;
  }

  /**
   * Retrieves the visibleIn property to determine where the mentions should be visible.
   */
  getVisibleIn() {
    return this.visibleIn;
  }

  /**
   * Retrieves the type of mention list.
   */
  getType() {
    return this.type;
  }

  getErrorString() {
    return `${t("MENTION_UPTO")} ${this.limit} ${
      this.limit === 1 ? t("TIME") : t("TIMES")
    } ${t("AT_A_TIME")}.`;
  }
}