/**
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

/**
 * This file contains LLM tool abstractions and tool definitions.
 */

import { searchBrowsingHistory as implSearchBrowsingHistory } from "moz-src:///browser/components/aiwindow/models/SearchBrowsingHistory.sys.mjs";
import { PageExtractorParent } from "resource://gre/actors/PageExtractorParent.sys.mjs";

const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
  AIWindow:
    "moz-src:///browser/components/aiwindow/ui/modules/AIWindow.sys.mjs",
  BrowserWindowTracker: "resource:///modules/BrowserWindowTracker.sys.mjs",
  PageDataService:
    "moz-src:///browser/components/pagedata/PageDataService.sys.mjs",
});

const GET_OPEN_TABS = "get_open_tabs";
const SEARCH_BROWSING_HISTORY = "search_browsing_history";
const GET_PAGE_CONTENT = "get_page_content";

export const TOOLS = [GET_OPEN_TABS, SEARCH_BROWSING_HISTORY, GET_PAGE_CONTENT];

export const toolsConfig = [
  {
    type: "function",
    function: {
      name: GET_OPEN_TABS,
      description:
        "Access the user's browser and return a list of most recently browsed tabs. " +
        "Each tab is represented by a JSON with the page's url, title and description " +
        "if available. Default to return maximum 15 tabs.",
      parameters: {
        type: "object",
        properties: {},
      },
    },
  },
  {
    type: "function",
    function: {
      name: SEARCH_BROWSING_HISTORY,
      description:
        "Retrieve pages from the user's past browsing history, optionally filtered by " +
        "topic and/or time range.",
      parameters: {
        type: "object",
        properties: {
          searchTerm: {
            type: "string",
            description:
              "A concise phrase describing what the user is trying to find in their " +
              "browsing history (topic, site, or purpose).",
          },
          startTs: {
            type: "string",
            description:
              "Inclusive start of the time range as a local ISO 8601 datetime " +
              "('YYYY-MM-DDTHH:mm:ss', no timezone).",
          },
          endTs: {
            type: "string",
            description:
              "Inclusive end of the time range as a local ISO 8601 datetime " +
              "('YYYY-MM-DDTHH:mm:ss', no timezone).",
          },
        },
      },
    },
  },
  {
    type: "function",
    function: {
      name: GET_PAGE_CONTENT,
      description:
        "Retrieve cleaned text content of the provided browser page URL.",
      parameters: {
        properties: {
          url: {
            type: "string",
            description:
              "The complete URL of the page to fetch content from. This must exactly match " +
              "a URL from the current conversation context. Use the full URL including " +
              "protocol (http/https). Example: 'https://www.example.com/article'.",
          },
        },
        required: ["url"],
      },
    },
  },
];

/**
 * Retrieves a list of (up to n) the latest open tabs from the current active browser window.
 * Ignores config pages (about:xxx).
 * TODO: Ignores chat-only pages (FE to implement isSidebarMode flag).
 *
 * @param {number} n
 *  Maximum number of tabs to return. Defaults to 15.
 * @returns {Promise<Array<object>>}
 *  A promise resolving to an array of tab metadata objects, each containing:
 *  - url {string}: The tab's current URL
 *  - title {string}: The tab's title
 *  - description {string}: Optional description (empty string if not available)
 *  - lastAccessed {number}: Last accessed timestamp in milliseconds
 *  Tabs are sorted by most recently accessed and limited to the first n results.
 */
export async function getOpenTabs(n = 15) {
  const tabs = [];

  for (const win of lazy.BrowserWindowTracker.orderedWindows) {
    if (!lazy.AIWindow.isAIWindowActive(win)) {
      continue;
    }

    if (!win.closed && win.gBrowser) {
      for (const tab of win.gBrowser.tabs) {
        const browser = tab.linkedBrowser;
        const url = browser?.currentURI?.spec;
        const title = tab.label;

        if (url && !url.startsWith("about:")) {
          tabs.push({
            url,
            title,
            lastAccessed: tab.lastAccessed,
          });
        }
      }
    }
  }

  tabs.sort((a, b) => b.lastAccessed - a.lastAccessed);

  const topTabs = tabs.slice(0, n);

  return Promise.all(
    topTabs.map(async ({ url, title, lastAccessed }) => {
      let description = "";
      if (url) {
        description =
          lazy.PageDataService.getCached(url)?.description ||
          (await lazy.PageDataService.fetchPageData(url))?.description ||
          "";
      }
      return { url, title, description, lastAccessed };
    })
  );
}

/**
 * Tool entrypoint for search_browsing_history.
 *
 * Parameters (defaults shown):
 * - searchTerm: ""        - string used for search
 * - startTs: null         - local ISO timestamp lower bound, or null
 * - endTs: null           - local ISO timestamp upper bound, or null
 * - historyLimit: 15      - max number of results
 *
 * Detailed behavior and implementation are in SearchBrowsingHistory.sys.mjs.
 *
 * @param {object} toolParams
 *  The search parameters.
 * @param {string} toolParams.searchTerm
 *  The search string. If null or empty, semantic search is skipped and
 *  results are filtered by time range and sorted by last_visit_date and frecency.
 * @param {string|null} toolParams.startTs
 *  Optional local ISO-8601 start timestamp (e.g. "2025-11-07T09:00:00").
 * @param {string|null} toolParams.endTs
 *  Optional local ISO-8601 end timestamp (e.g. "2025-11-07T09:00:00").
 * @param {number} toolParams.historyLimit
 *  Maximum number of history results to return.
 * @returns {Promise<object>}
 *  A promise resolving to an object with the search term and history results.
 *  Includes `count` when matches exist, a `message` when none are found, or an
 *  `error` string on failure.
 */
export async function searchBrowsingHistory({
  searchTerm = "",
  startTs = null,
  endTs = null,
  historyLimit = 15,
}) {
  return implSearchBrowsingHistory({
    searchTerm,
    startTs,
    endTs,
    historyLimit,
  });
}

/**
 * Strips heavy or unnecessary fields from a browser history search result.
 *
 * @param {string} result
 *  A JSON string representing the history search response.
 * @returns {string}
 *  The sanitized JSON string with large fields (e.g., favicon, thumbnail)
 *  removed, or the original string if parsing fails.
 */
export function stripSearchBrowsingHistoryFields(result) {
  try {
    const data = JSON.parse(result);
    if (
      data.error ||
      !Array.isArray(data.results) ||
      data.results.length === 0
    ) {
      return result;
    }

    // Remove large or unnecessary fields to save tokens
    const OMIT_KEYS = ["favicon", "thumbnail"];
    for (const item of data.results) {
      if (item && typeof item === "object") {
        for (const k of OMIT_KEYS) {
          delete item[k];
        }
      }
    }
    return JSON.stringify(data);
  } catch {
    return result;
  }
}

/**
 * Class for handling page content extraction with configurable modes and limits.
 */
export class GetPageContent {
  static DEFAULT_MODE = "reader";
  static FALLBACK_MODE = "full";
  static MAX_CHARACTERS = 10000;

  static MODE_HANDLERS = {
    viewport: async pageExtractor => {
      const result = await pageExtractor.getText({ justViewport: true });
      return { text: result.text };
    },
    reader: async pageExtractor => {
      const text = await pageExtractor.getReaderModeContent();
      return { text: typeof text === "string" ? text : "" };
    },
    full: async pageExtractor => {
      const result = await pageExtractor.getText();
      return { text: result };
    },
  };

  /**
   * Tool entrypoint for get_page_content.
   *
   * @param {object} toolParams
   * @param {string} toolParams.url
   * @param {Set<string>} allowedUrls
   * @returns {Promise<string>}
   *  A promise resolving to a string containing the extracted page content
   *  with a descriptive header, or an error message if extraction fails.
   */
  static async getPageContent({ url }, allowedUrls) {
    try {
      // Search through the allowed URLs and extract directly if exists
      if (!allowedUrls.has(url)) {
        //  Bug 2006418  - This will load the page headlessly, and then extract the content.
        // It might be a better idea to have the lifetime of the page be tied to the chat
        // while it's open, and with a "keep alive" timeout. For now it's simpler to just
        // load the page fresh every time.
        return PageExtractorParent.getHeadlessExtractor(url, pageExtractor =>
          this.#runExtraction(pageExtractor, this.DEFAULT_MODE, url)
        );
      }

      // Search through all AI Windows to find the tab with the matching URL
      let targetTab = null;
      for (const win of lazy.BrowserWindowTracker.orderedWindows) {
        if (!lazy.AIWindow.isAIWindowActive(win)) {
          continue;
        }

        if (!win.closed && win.gBrowser) {
          const tabs = win.gBrowser.tabs;

          // Find the tab with the matching URL in this window
          for (let i = 0; i < tabs.length; i++) {
            const tab = tabs[i];
            const currentURI = tab?.linkedBrowser?.currentURI;
            if (currentURI?.spec === url) {
              targetTab = tab;
              break;
            }
          }

          // If no match, try hostname matching for cases where protocols differ
          if (!targetTab) {
            try {
              const inputHostPort = new URL(url).host;
              targetTab = tabs.find(tab => {
                try {
                  const tabHostPort = tab.linkedBrowser.currentURI.hostPort;
                  return tabHostPort === inputHostPort;
                } catch {
                  return false;
                }
              });
            } catch {
              // Invalid URL, continue with original logic
            }
          }

          // If we found the tab, stop searching
          if (targetTab) {
            break;
          }
        }
      }

      // If still no match, abort
      if (!targetTab) {
        return `Cannot find URL: ${url}, page content extraction failed.`;
      }

      // Attempt extraction
      const currentWindowContext =
        targetTab.linkedBrowser.browsingContext?.currentWindowContext;

      if (!currentWindowContext) {
        return `Cannot access content from "${targetTab.label}" at ${url}.`;
        // Stripped message "The tab may still be loading or is not accessible." to not confuse the LLM
      }

      // Extract page content using PageExtractor
      const pageExtractor =
        await currentWindowContext.getActor("PageExtractor");

      return this.#runExtraction(
        pageExtractor,
        this.DEFAULT_MODE,
        `"${targetTab.label}" (${url})`
      );
    } catch (error) {
      // Bug 2006425 - Decide on the strategy for error handling in tool calls
      // i.e., will the LLM keep retrying get_page_content due to error?
      console.error(error);
      return `Error retrieving content from ${url}.`;
      // Stripped ${error.message} content to not confruse the LLM
    }
  }

  /**
   * Main extraction function.
   * label is of form `{tab.title} ({tab.url})`.
   *
   * @param {PageExtractor} pageExtractor
   * @param {string} mode
   * @param {string} label
   * @returns {Promise<string>}
   *  A promise resolving to a formatted string containing the page content
   *  with mode and label information, or an error message if no content is available.
   */
  static async #runExtraction(pageExtractor, mode, label) {
    const selectedMode =
      typeof mode === "string" && this.MODE_HANDLERS[mode]
        ? mode
        : this.DEFAULT_MODE;
    const handler = this.MODE_HANDLERS[selectedMode];
    let extraction = null;

    try {
      extraction = await handler(pageExtractor);
    } catch (err) {
      console.error(
        "[SmartWindow] get_page_content mode failed",
        selectedMode,
        err
      );
    }

    let pageContent = "";
    if (typeof extraction === "string") {
      pageContent = extraction;
    } else if (typeof extraction?.text === "string") {
      pageContent = extraction.text;
    }

    // Track which mode was actually used (in case we fall back)
    let actualMode = selectedMode;

    // If reader mode returns no content, fall back to full mode
    if (!pageContent && selectedMode === "reader") {
      try {
        const fallbackHandler = this.MODE_HANDLERS[this.FALLBACK_MODE];
        extraction = await fallbackHandler(pageExtractor);
        if (typeof extraction === "string") {
          pageContent = extraction;
        } else if (typeof extraction?.text === "string") {
          pageContent = extraction.text;
        }
        if (pageContent) {
          actualMode = this.FALLBACK_MODE;
        }
      } catch (err) {
        console.error(
          "[SmartWindow] get_page_content fallback mode failed",
          this.FALLBACK_MODE,
          err
        );
      }
    }

    if (!pageContent) {
      return `get_page_content(${selectedMode}) returned no content for ${label}.`;
      // Stripped message "Try another mode if you still need information." to not confruse the LLM
    }

    // Clean and truncate content for better LLM consumption
    //  Bug 2006436 - Consider doing this directly in pageExtractor if absolutely needed.
    let cleanContent = pageContent
      .replace(/\s+/g, " ") // Normalize whitespace
      .replace(/\n\s*\n/g, "\n") // Clean up line breaks
      .trim();

    // Limit content length but be more generous for LLM processing
    // Bug 1995043 - once reader mode has length truncation,
    // we can remove this and directly do this in pageExtractor.
    if (cleanContent.length > this.MAX_CHARACTERS) {
      // Try to cut at a sentence boundary
      const truncatePoint = cleanContent.lastIndexOf(".", this.MAX_CHARACTERS);
      if (truncatePoint > this.MAX_CHARACTERS - 100) {
        cleanContent = cleanContent.substring(0, truncatePoint + 1);
      } else {
        cleanContent = cleanContent.substring(0, this.MAX_CHARACTERS) + "...";
      }
    }

    let modeLabel;
    switch (actualMode) {
      case "viewport":
        modeLabel = "current viewport";
        break;
      case "reader":
        modeLabel = "reader mode";
        break;
      case "full":
        modeLabel = "full page";
        break;
    }

    return `Content (${modeLabel}) from ${label}:

${cleanContent}`;
  }
}