from __future__ import annotations

import json
import pandas as pd
from io import StringIO, BytesIO
import re
import hashlib
import logging
import csv

import tiktoken
from bs4 import BeautifulSoup, Comment
from urllib.parse import urlparse
from langchain_google_genai import ChatGoogleGenerativeAI
from langchain_text_splitters import RecursiveCharacterTextSplitter

from .models import Models
from .ollama_models import OllamaModel, OllamaModelManager
from .scrapers.playwright_scraper import ScraperConfig
from .scrapers.scrapling_adapter import ScraplingAdapter as PlaywrightScraper
from .utils.error_handler import ErrorMessages, check_model_api_key
from .prompts import get_prompt_for_model
from .scrapers.tor.tor_scraper import TorScraper
from .scrapers.tor.tor_config import TorConfig
from .scrapers.tor.exceptions import TorException
from .utils.browser_tools import get_all_browser_tools

logger = logging.getLogger(__name__)

# Module-level cached tiktoken encoding (singleton pattern)
_TIKTOKEN_ENCODING: tiktoken.Encoding | None = None


def _get_tiktoken_encoding() -> tiktoken.Encoding:
    """Get or create cached tiktoken encoding. Saves ~100-200ms per call."""
    global _TIKTOKEN_ENCODING
    if _TIKTOKEN_ENCODING is None:
        _TIKTOKEN_ENCODING = tiktoken.encoding_for_model("gpt-4o-mini")
    return _TIKTOKEN_ENCODING


# Precompiled regex patterns for JSON extraction
_JSON_BLOCK_PATTERN = re.compile(r'```json\s*([\s\S]*?)\s*```')
_CODE_BLOCK_PATTERN = re.compile(r'```\s*([\s\S]*?)\s*```')
# Pattern to find JSON array in text (handles arrays that might have text before/after)
_JSON_ARRAY_PATTERN = re.compile(r'\[\s*\{[\s\S]*?\}\s*\]')
# URL extraction pattern
_URL_PATTERN = re.compile(r'https?://[^\s/$.?#][^\s]*', re.IGNORECASE)


def extract_url(text: str) -> str | None:
    """Extract URL from anywhere in the text using regex."""
    match = _URL_PATTERN.search(text)
    return match.group(0) if match else None


def get_website_name(url: str) -> str:
    """Extract a clean website name from URL."""
    parsed_url = urlparse(url)
    domain = parsed_url.netloc
    if domain.startswith('www.'):
        domain = domain[4:]
    name = domain.split('.')[0].capitalize()
    # Truncate long names (e.g., onion URLs)
    if len(name) > 15:
        name = name[:12] + "..."
    return name


# Tags to remove during preprocessing (single pass)
_REMOVE_TAGS = frozenset(['script', 'style', 'header', 'footer', 'nav', 'aside'])

class WebExtractor:
    def __init__(
        self,
        model_name: str = "gpt-4.1-mini",
        model_kwargs: dict | None = None,
        scraper_config: ScraperConfig | None = None,
        tor_config: TorConfig | None = None
    ):
        model_kwargs = model_kwargs or {}

        # Check for required API keys before initializing
        api_key_error = check_model_api_key(model_name)
        if api_key_error:
            logger.warning(api_key_error)

        if isinstance(model_name, str) and model_name.startswith("ollama:"):
            self.model = OllamaModelManager.get_model(model_name[7:])
        elif isinstance(model_name, OllamaModel):
            self.model = model_name
        elif model_name.startswith("gemini-"):
            self.model = ChatGoogleGenerativeAI(model=model_name, **model_kwargs)
        else:
            self.model = Models.get_model(model_name, **model_kwargs)

        self.model_name = model_name
        self.scraper_config = scraper_config or ScraperConfig()
        self.playwright_scraper = PlaywrightScraper(config=self.scraper_config)
        self.current_url: str | None = None
        self.current_content: str | None = None
        self.preprocessed_content: str | None = None
        self.conversation_history: list[str] = []
        self.text_splitter = RecursiveCharacterTextSplitter(
            chunk_size=32000,
            chunk_overlap=200,
            length_function=self.num_tokens_from_string,
        )
        self.max_tokens = 128000 if model_name in ("gpt-4.1-mini", "gpt-4o-mini") else 16385
        self.query_cache: dict[tuple, str] = {}
        self.content_hash: str | None = None
        self.tor_config = tor_config or TorConfig()
        self.tor_scraper = TorScraper(self.tor_config)
        self.tools = get_all_browser_tools()

    @staticmethod
    def num_tokens_from_string(string: str) -> int:
        encoding = _get_tiktoken_encoding()
        return len(encoding.encode(string))

    def _hash_content(self, content: str) -> str:
        return hashlib.md5(content.encode()).hexdigest()

    def _format_conversation_history(self, conversation_history: list[dict] | None) -> str:
        """Format conversation history for the prompt."""
        if not conversation_history:
            return "No previous conversation."

        history_text = ""
        # Use last 10 messages for context
        recent_history = conversation_history[-10:]
        for msg in recent_history:
            role = "User" if msg.get("role") == "user" else "Assistant"
            content = msg.get("content", "")
            # Truncate very long messages to avoid token overflow
            if len(content) > 500:
                content = content[:500] + "..."
            history_text += f"{role}: {content}\n\n"

        return history_text.strip() if history_text else "No previous conversation."

    async def _call_model(self, query: str, conversation_history: list[dict] | None = None, progress_callback=None) -> str:
        """Call the model to extract information from preprocessed content, with tool support if available."""

        # Check if the model supports tool calling
        if hasattr(self.model, "bind_tools") and not isinstance(self.model, OllamaModel):
            return await self._call_model_with_tools(query, conversation_history, progress_callback=progress_callback)

        prompt_template = get_prompt_for_model(self.model_name)

        # Format conversation history
        history_text = self._format_conversation_history(conversation_history)

        if isinstance(self.model, OllamaModel):
            full_prompt = prompt_template.format(
                conversation_history=history_text,
                webpage_content=self.preprocessed_content,
                query=query
            )
            return await self.model.generate(prompt=full_prompt)
        else:
            chain = prompt_template | self.model
            response = await chain.ainvoke({
                "conversation_history": history_text,
                "webpage_content": self.preprocessed_content,
                "query": query
            })
            return response.content

    async def _call_model_with_tools(self, query: str, conversation_history: list[dict] | None = None, progress_callback=None) -> str:
        """Execute an iterative, agentic tool-calling loop with the model."""
        from langchain_core.messages import HumanMessage, SystemMessage, ToolMessage, AIMessage

        history_text = self._format_conversation_history(conversation_history)

        system_prompt = f"""You are a master netrunner AI with the personality of Rebecca from Cyberpunk 2077.
You help users scrape and extract data through continuous and iterative investigation.

Current URL: {self.current_url}
Current webpage content (preprocessed snippet):
{self.preprocessed_content[:2000] if self.preprocessed_content else "None"}

Conversation history:
{history_text}

MISSION PARAMETERS:
1. INVESTIGATE: Use your tools (click, scroll, get_page_info, wait_for_element) to explore the site iteratively.
2. PERSIST: If you hit a captcha or get blocked, try to get_cookies, set_cookies, or execute_javascript to bypass.
3. VERIFY & REFLECT: After every action, check the new state. If an action failed or didn't yield the expected result, REFLECT on why and ADAPT your strategy.
4. EXTRACT: Once you have the data, format it as requested.
5. CONCLUDE: You MUST call the `task_complete` tool when you have the final answer or data.

CRITICAL: Before every tool call, provide a brief "THOUGHT" on what you've learned so far and why you are taking the next step. If you encounter an error, analyze it and try a different selector or approach.
DO NOT stop until you call `task_complete`. You are a persistent autonomous agent.
"""

        messages = [
            SystemMessage(content=system_prompt),
            HumanMessage(content=query)
        ]

        model_with_tools = self.model.bind_tools(self.tools)

        # Iterative execution loop (max 12 iterations for autonomous behavior)
        for i in range(12):
            try:
                if progress_callback:
                    progress_callback(f"Rebecca is thinking (iteration {i+1}/12)...")

                response = await model_with_tools.ainvoke(messages)
                messages.append(response)

                if not response.tool_calls:
                    # If the AI says it's done but didn't call task_complete,
                    # we nudge it or accept if it looks like a final answer.
                    if "TASK COMPLETE" in response.content or len(response.content) > 50:
                        return response.content

                    messages.append(HumanMessage(content="You haven't called `task_complete` yet. Are you done? If not, continue investigating. If yes, call `task_complete` with your summary."))
                    continue

                for tool_call in response.tool_calls:
                    tool_name = tool_call["name"].lower()
                    tool_args = tool_call["args"]

                    # Ensure URL is passed if missing and available
                    if "url" not in tool_args and self.current_url:
                        tool_args["url"] = self.current_url

                    # Find and execute the tool
                    selected_tool = next((t for t in self.tools if t.name.lower() == tool_name), None)
                    if selected_tool:
                        if progress_callback:
                            progress_callback(f"Executing {tool_name}...")
                        try:
                            # Use use_persistent=True for iterative session if possible
                            if "use_persistent" in tool_args:
                                tool_args["use_persistent"] = True

                            observation = selected_tool.invoke(tool_args)

                            if tool_name == "task_complete":
                                return response.content if response.content else str(observation)

                            # If action might change state, append a hint for the AI
                            if tool_name in ["click_element", "fill_field", "execute_javascript", "scroll_page"]:
                                observation = f"ACTION SUCCESSFUL. {observation}\nPRO-TIP: Use get_page_info or browse_and_extract to see if the page state changed."
                        except Exception as e:
                            observation = f"ERROR executing tool {tool_name}: {str(e)}\nTry a different approach or selector."
                    else:
                        observation = f"Tool {tool_name} not found."

                    messages.append(ToolMessage(content=str(observation), tool_call_id=tool_call["id"]))
            except Exception as e:
                logger.error(f"Error in agentic loop iteration {i}: {e}", exc_info=True)
                return f"Error in agentic loop (iteration {i}): {str(e)}"

        return messages[-1].content if hasattr(messages[-1], "content") else str(messages[-1])

    @staticmethod
    def _is_page_spec(value: str) -> bool:
        """Check if a string is a valid page specification (e.g., '1-5', '1,3,5', '2')."""
        if not value:
            return False
        # Valid page specs contain only digits, dashes, and commas
        return all(c.isdigit() or c in '-,' for c in value) and any(c.isdigit() for c in value)

    async def _chat_without_content(self, query: str, conversation_history: list[dict] | None = None) -> str:
        """Handle chat when no URL has been scraped yet - let LLM respond naturally."""
        history_text = self._format_conversation_history(conversation_history)

        prompt = f"""You are a netrunner AI with the personality of Rebecca from Cyberpunk 2077 / Edgerunners. Keep the attitude subtle but present.

You help users scrape and extract data from websites. Currently, no URL has been provided yet.

Respond to the user's message naturally. If they're greeting you or chatting, chat back! Guide them to provide a URL when appropriate so you can start scraping.

CyberScraper-2077:
{history_text}

User: {query}"""

        if isinstance(self.model, OllamaModel):
            return await self.model.generate(prompt=prompt)
        else:
            response = await self.model.ainvoke(prompt)
            return response.content

    async def process_query(self, user_input: str, conversation_history: list[dict] | None = None, progress_callback=None) -> str:
        url = extract_url(user_input)
        if url:
            self.current_url = url
            # Get text after the URL for parsing parameters
            url_match = _URL_PATTERN.search(user_input)
            text_after_url = user_input[url_match.end():].strip()

            parts = text_after_url.split(maxsplit=2)
            # Only treat as pages if it looks like a page specification (e.g., "1-5", "1,3,5")
            pages = parts[0] if len(parts) > 0 and self._is_page_spec(parts[0]) else None
            url_pattern = parts[1] if len(parts) > 1 and not parts[1].startswith('-') else None
            handle_captcha = '-captcha' in user_input.lower()

            website_name = get_website_name(url)

            if progress_callback:
                progress_callback(f"Fetching initial content from {website_name}...")

            # Initial fetch to get the ball rolling
            fetch_response = await self._fetch_url(url, pages, url_pattern, handle_captcha, progress_callback)

            if self.current_content:
                # If fetch worked, immediately start the agentic extraction/investigation
                if progress_callback:
                    progress_callback(f"Investigating {website_name} autonomously...")

                # We use the original user input as the mission
                response = await self._extract_info(user_input, conversation_history, progress_callback=progress_callback)
            else:
                # If fetch failed, return the error from fetch
                response = fetch_response
        elif not self.current_content:
            # No URL yet - let LLM chat naturally
            if progress_callback:
                progress_callback("Chatting...")
            response = await self._chat_without_content(user_input, conversation_history)
        else:
            if progress_callback:
                progress_callback("Extracting information...")
            response = await self._extract_info(user_input, conversation_history)

        self.conversation_history.append(f"Human: {user_input}")
        self.conversation_history.append(f"AI: {response}")
        return response

    async def _fetch_url(self, url: str, pages: Optional[str] = None,
                        url_pattern: Optional[str] = None,
                        handle_captcha: bool = False,
                        progress_callback=None) -> str:
        self.current_url = url

        try:
            # Check if it's an onion URL
            if TorScraper.is_onion_url(url):
                if progress_callback:
                    progress_callback("Fetching content through Tor network...")

                content = await self.tor_scraper.fetch_content(url)
                self.current_content = content

            else:
                # Regular scraping without Tor
                if progress_callback:
                    progress_callback(f"Fetching content from {url}")

                # Don't use proxy for non-onion URLs
                contents = await self.playwright_scraper.fetch_content(
                    url,
                    proxy=None,  # Explicitly set proxy to None for regular URLs
                    pages=pages,
                    url_pattern=url_pattern,
                    handle_captcha=handle_captcha
                )

                # Check if scraping failed - only match if content starts with "Error:"
                # (not just contains it, as HTML pages often have "Error:" in scripts)
                if contents and any(str(c).strip().startswith("Error:") for c in contents):
                    return f"{ErrorMessages.SCRAPING_FAILED}\n\nDetails: {' '.join(contents)}"

                self.current_content = "\n".join(contents)

            if progress_callback:
                progress_callback("Preprocessing content...")

            self.preprocessed_content = self._preprocess_content(self.current_content)

            new_hash = self._hash_content(self.preprocessed_content)
            if self.content_hash != new_hash:
                self.content_hash = new_hash
                self.query_cache.clear()

            source_type = "Tor network" if TorScraper.is_onion_url(url) else "regular web"
            return f"I've fetched and preprocessed the content from {self.current_url} via {source_type}" + \
                (f" (pages: {pages})" if pages else "") + \
                ". What would you like to know about it?"

        except TorException as e:
            return str(e)
        except Exception as e:
            logger.error(f"Error fetching content: {str(e)}")
            return f"{ErrorMessages.SCRAPING_FAILED}\n\nDetails: {str(e)}"

    def _preprocess_content(self, content: str) -> str:
        # Use lxml parser for better performance
        soup = BeautifulSoup(content, 'lxml')

        # Single pass: remove unwanted tags and comments
        for element in soup.find_all(_REMOVE_TAGS):
            element.decompose()

        for comment in soup.find_all(string=lambda text: isinstance(text, Comment)):
            comment.extract()

        # Remove empty tags in one pass
        for tag in soup.find_all():
            if len(tag.get_text(strip=True)) == 0:
                tag.extract()

        text = soup.get_text()

        # Efficient text cleanup using generator expressions
        lines = (line.strip() for line in text.splitlines())
        chunks = (phrase.strip() for line in lines for phrase in line.split("  "))
        return '\n'.join(chunk for chunk in chunks if chunk)

    async def _extract_info(self, query: str, conversation_history: list[dict] | None = None, progress_callback=None) -> str:
        if not self.preprocessed_content:
            return await self._chat_without_content(query, conversation_history)

        content_hash = self._hash_content(self.preprocessed_content)

        if self.content_hash != content_hash:
            self.content_hash = content_hash
            self.query_cache.clear()

        # Cache key includes model_name to prevent cross-model cache hits
        # Note: We don't include conversation_history in cache key since conversational
        # responses should consider the full context each time
        cache_key = (content_hash, query, self.model_name)

        # Only use cache for explicit data export requests (not conversational queries)
        export_keywords = ['csv', 'json', 'excel', 'sql', 'html', 'export', 'extract', 'give me the data', 'table']
        is_export_request = any(keyword in query.lower() for keyword in export_keywords)

        if is_export_request and cache_key in self.query_cache:
            return self.query_cache[cache_key]

        content_tokens = self.num_tokens_from_string(self.preprocessed_content)

        if content_tokens <= self.max_tokens - 1000:
            extracted_data = await self._call_model(query, conversation_history, progress_callback=progress_callback)
        else:
            chunks = self.optimized_text_splitter(self.preprocessed_content)
            # Store original content, process chunks, restore
            original_content = self.preprocessed_content
            all_extracted_data = []
            for chunk in chunks:
                self.preprocessed_content = chunk
                chunk_data = await self._call_model(query, conversation_history, progress_callback=progress_callback)
                all_extracted_data.append(chunk_data)
            self.preprocessed_content = original_content
            extracted_data = self._merge_json_chunks(all_extracted_data)

        formatted_result = self._format_result(extracted_data, query)

        # Only cache export requests
        if is_export_request:
            self.query_cache[cache_key] = formatted_result

        return formatted_result

    def _extract_json_data(self, extracted_data: str) -> list | dict | None:
        """Try multiple methods to extract JSON data from the response."""
        # Method 1: Try direct JSON parse
        try:
            return json.loads(extracted_data)
        except json.JSONDecodeError:
            pass

        # Method 2: Try extracting from markdown code blocks
        clean_data = self._extract_json_from_markdown(extracted_data)
        if clean_data != extracted_data:
            try:
                return json.loads(clean_data)
            except json.JSONDecodeError:
                pass

        # Method 3: Try finding JSON array pattern in text
        if match := _JSON_ARRAY_PATTERN.search(extracted_data):
            try:
                return json.loads(match.group(0))
            except json.JSONDecodeError:
                pass

        return None

    def _format_result(self, extracted_data: str, query: str) -> str | tuple[str, pd.DataFrame] | BytesIO:
        query_lower = query.lower()
        export_keywords = ['csv', 'json', 'excel', 'sql', 'html', 'export', 'extract', 'give me the data', 'table', 'download', 'file']

        # Only try to parse as JSON if user explicitly requested data export
        if any(keyword in query_lower for keyword in export_keywords):
            json_data = self._extract_json_data(extracted_data)

            if json_data is not None:
                if 'json' in query_lower:
                    return self._format_as_json(json.dumps(json_data))
                elif 'csv' in query_lower or 'file' in query_lower or 'download' in query_lower:
                    csv_string, df = self._format_as_csv(json.dumps(json_data))
                    return f"```csv\n{csv_string}\n```", df
                elif 'excel' in query_lower:
                    return self._format_as_excel(json.dumps(json_data))
                elif 'sql' in query_lower:
                    return self._format_as_sql(json.dumps(json_data))
                elif 'html' in query_lower:
                    return self._format_as_html(json.dumps(json_data))
                else:
                    # For generic export keywords (export, extract, table, give me the data)
                    if isinstance(json_data, list) and all(isinstance(item, dict) for item in json_data):
                        csv_string, df = self._format_as_csv(json.dumps(json_data))
                        return f"```csv\n{csv_string}\n```", df
                    else:
                        return self._format_as_json(json.dumps(json_data))

            # If JSON extraction fails for an export request, return as-is
            return extracted_data

        # For conversational responses, return as-is (no JSON parsing)
        return extracted_data

    def optimized_text_splitter(self, text: str) -> List[str]:
        return self.text_splitter.split_text(text)

    def _merge_json_chunks(self, chunks: List[str]) -> str:
        merged_data = []
        for chunk in chunks:
            try:
                data = json.loads(chunk)
                if isinstance(data, list):
                    merged_data.extend(data)
                else:
                    merged_data.append(data)
            except json.JSONDecodeError:
                print(f"Error decoding JSON chunk: {chunk[:100]}...")
        return json.dumps(merged_data)

    @staticmethod
    def _extract_json_from_markdown(data: str) -> str:
        """Extract JSON content from markdown code blocks using precompiled patterns."""
        if match := _JSON_BLOCK_PATTERN.search(data):
            return match.group(1)
        if match := _CODE_BLOCK_PATTERN.search(data):
            return match.group(1)
        return data

    def _format_as_json(self, data: str) -> str:
        data = self._extract_json_from_markdown(data)
        try:
            parsed_data = json.loads(data)
            return f"```json\n{json.dumps(parsed_data, indent=2)}\n```"
        except json.JSONDecodeError:
            return f"Error: Invalid JSON data. Raw data: {data[:500]}..."

    def _format_as_csv(self, data: str) -> tuple[str, pd.DataFrame]:
        data = self._extract_json_from_markdown(data)
        try:
            parsed_data = json.loads(data)
            if not parsed_data:
                return "No data to convert to CSV.", pd.DataFrame()

            output = StringIO()
            writer = csv.DictWriter(output, fieldnames=parsed_data[0].keys())
            writer.writeheader()
            writer.writerows(parsed_data)
            csv_string = output.getvalue()

            df = pd.DataFrame(parsed_data)

            return csv_string, df
        except json.JSONDecodeError:
            error_msg = f"Error: Invalid JSON data. Raw data: {data[:500]}..."
            return error_msg, pd.DataFrame()
        except Exception as e:
            error_msg = f"Error: Failed to convert data to CSV. {str(e)}"
            return error_msg, pd.DataFrame()

    def _format_as_excel(self, data: str) -> tuple[BytesIO, pd.DataFrame]:
        data = self._extract_json_from_markdown(data)
        try:
            parsed_data = json.loads(data)
            if not parsed_data:
                return BytesIO(b"No data to convert to Excel."), pd.DataFrame()

            df = pd.DataFrame(parsed_data)
            excel_buffer = BytesIO()
            with pd.ExcelWriter(excel_buffer, engine='xlsxwriter') as writer:
                df.to_excel(writer, index=False, sheet_name='Sheet1')
            excel_buffer.seek(0)

            return excel_buffer, df
        except json.JSONDecodeError:
            error_msg = f"Error: Invalid JSON data. Raw data: {data[:500]}..."
            return BytesIO(error_msg.encode()), pd.DataFrame()
        except Exception as e:
            error_msg = f"Error: Failed to convert data to Excel. {str(e)}"
            return BytesIO(error_msg.encode()), pd.DataFrame()

    def _format_as_sql(self, data: str) -> str:
        data = self._extract_json_from_markdown(data)
        try:
            parsed_data = json.loads(data)
            if not parsed_data:
                return "No data to convert to SQL."

            fields = ", ".join([f"{k} TEXT" for k in parsed_data[0].keys()])
            sql_parts = [f"CREATE TABLE extracted_data ({fields});"]

            for row in parsed_data:
                escaped_values = [str(v).replace("'", "''") for v in row.values()]
                values = ", ".join([f"'{v}'" for v in escaped_values])
                sql_parts.append(f"INSERT INTO extracted_data VALUES ({values});")

            return f"```sql\n{chr(10).join(sql_parts)}\n```"
        except json.JSONDecodeError:
            return f"Error: Invalid JSON data. Raw data: {data[:500]}..."

    def _format_as_html(self, data: str) -> str:
        data = self._extract_json_from_markdown(data)
        try:
            parsed_data = json.loads(data)
            if not parsed_data:
                return "No data to convert to HTML."

            html_parts = ["<table>", "<tr>"]
            html_parts.extend([f"<th>{k}</th>" for k in parsed_data[0].keys()])
            html_parts.append("</tr>")

            for row in parsed_data:
                html_parts.append("<tr>")
                html_parts.extend([f"<td>{v}</td>" for v in row.values()])
                html_parts.append("</tr>")

            html_parts.append("</table>")

            return f"```html\n{''.join(html_parts)}\n```"
        except json.JSONDecodeError:
            return f"Error: Invalid JSON data. Raw data: {data[:500]}..."

    @staticmethod
    async def list_ollama_models() -> List[str]:
        return await OllamaModel.list_models()