import os
import requests
from bs4 import BeautifulSoup
from duckduckgo_search import DDGS

class SimpleTextBrowser:
    def __init__(
        self,
        timeout: int = 10,
        user_agent: str | None = None,
        viewport_size: int = 5000,
        downloads_folder: str = "downloads",
    ):
        self.session = requests.Session()
        self.session.headers.update({"User-Agent": user_agent or "Mozilla/5.0"})
        self.timeout = timeout
        self.viewport_size = viewport_size
        os.makedirs(downloads_folder, exist_ok=True)
        self.pages: list[str] = [""]
        self._idx = 0

    def _split(self, text: str):
        self.pages = [
            text[i : i + self.viewport_size]
            for i in range(0, len(text), self.viewport_size)
        ]
        self._idx = 0

    def visit_page(self, url: str) -> str:
        """
        Internal: fetch and split a page into viewports.
        """
        resp = self.session.get(url, timeout=self.timeout)
        resp.raise_for_status()
        text = resp.text
        if "text/html" in resp.headers.get("content-type", ""):
            text = BeautifulSoup(text, "lxml").get_text("\n")
        self._split(text)
        return self.pages[self._idx]

    def search(self, query: str) -> str:
        """
        Internal: DuckDuckGo search → snippets.
        """
        results = list(DDGS().text(query, timelimit=None))
        hits = "\n".join(
            f"{i+1}. {h['title']} — {h.get('snippet','')}"
            for i, h in enumerate(results)
        )
        full = f"Search results for '{query}':\n\n" + hits
        self._split(full)
        return self.pages[self._idx]

    def page_down(self) -> str:
        self._idx = min(self._idx + 1, len(self.pages) - 1)
        return self.pages[self._idx]

    def page_up(self) -> str:
        self._idx = max(self._idx - 1, 0)
        return self.pages[self._idx]

    def find_on_page(self, search_string: str) -> str:
        full = "\n".join(self.pages).lower()
        pos = full.find(search_string.lower())
        if pos < 0:
            return f"'{search_string}' not found."
        start = max(0, pos - 100)
        end = min(len(full), pos + 100)
        return full[start:end]

    def find_next(self) -> str:
        return "Use `find_on_page_ctrl_f` again with a new string to find further occurrences."

# one shared browser instance:
_BROWSER = SimpleTextBrowser()