import os
from typing import Optional, List, Dict, Any
from slack_sdk import WebClient

from health.utils.logging_config import setup_logger
from slack_bot.obsidian.indexer import ObsidianIndexer
from slack_bot.obsidian.generators import WritingAssistant, ReplyGenerator, DecisionSupport, SearchAnalyzer, DeAIReviser, ZhihuGenerator
from slack_bot.context.storage import ContextStorage as BaseStorage

logger = setup_logger(__name__)

class ObsidianContextStorage(BaseStorage):
    """Specific storage for Obsidian bot to avoid mixing with Health bot."""
    def __init__(self, channel_id: str):
        super().__init__(channel_id)
        from health import config
        self.context_dir = config.DATA_DIR / "obsidian_context"
        self.context_dir.mkdir(parents=True, exist_ok=True)
        self.file_path = self.context_dir / f"{channel_id}.json"
        self.state_file = self.context_dir / f"{channel_id}_state.json"

    def save_state(self, state: Dict[str, Any]):
        import json
        with open(self.state_file, "w") as f:
            json.dump(state, f)

    def load_state(self) -> Dict[str, Any]:
        import json
        if not self.state_file.exists():
            return {"mode": "none"}
        try:
            with open(self.state_file, "r") as f:
                return json.load(f)
        except:
            return {"mode": "none"}

class ObsidianDispatcher:
    """Routes Obsidian Slack Bot messages."""

    MODE_WRITE = "write"
    MODE_REPLY = "reply"
    MODE_DECIDE = "decide"
    MODE_SEARCH = "search"
    MODE_DEAI = "deai"
    MODE_ZHIHU = "zhihu"

    def __init__(self, vault_path: str):
        self.indexer = ObsidianIndexer(vault_path)
        self.indexer.scan_vault()

        self.generators = {
            self.MODE_WRITE: WritingAssistant(self.indexer),
            self.MODE_REPLY: ReplyGenerator(self.indexer),
            self.MODE_DECIDE: DecisionSupport(self.indexer),
            self.MODE_SEARCH: SearchAnalyzer(self.indexer),
            self.MODE_DEAI: DeAIReviser(self.indexer),
            self.MODE_ZHIHU: ZhihuGenerator(self.indexer)
        }
        
        token = os.environ.get("OBSIDIAN_SLACK_BOT_TOKEN")
        self.client = WebClient(token=token)
        logger.info("ObsidianDispatcher initialized")

    def dispatch(self, text: str, channel_id: str, user_id: str, response_ts: Optional[str] = None):
        storage = ObsidianContextStorage(channel_id)
        state = storage.load_state()
        current_mode = state.get("mode", "none")
        
        cmd = text.strip().lower()
        
        # 1. Handle Commands
        if cmd.startswith("mode "):
            new_mode = cmd.split(" ", 1)[1].strip()
            if new_mode in self.generators:
                storage.clear()
                storage.save_state({"mode": new_mode})
                self._reply(channel_id, f"✅ Switched to mode: *{new_mode}* (History cleared)", response_ts)
                return
            else:
                self._reply(channel_id, f"❌ Invalid mode. Available: {', '.join(self.generators.keys())}", response_ts)
                return
        
        if cmd == "clear":
            storage.clear()
            self._reply(channel_id, "🧹 Context cleared.", response_ts)
            return
            
        if cmd == "reload":
            self.indexer.scan_vault()
            self._reply(channel_id, "🔄 Vault reloaded.", response_ts)
            return

        # 2. Handle Content based on mode
        if current_mode == "none":
            self._reply(channel_id, "⚠️ No mode selected. Use `mode write/reply/decide/search/deai/zhihu` to start.", response_ts)
            return

        # Get history
        history = storage.get_context()
        generator = self.generators[current_mode]
        
        try:
            logger.info(f"Generating Obsidian response in mode: {current_mode}")
            # The chat method handles first turn logic and returns updated history
            # But wait, our generators' chat method appends to history internally. 
            # In our Slack setup, we want to append the result to ContextStorage.
            
            # Note: generator.chat(text, history) returns (response, new_history_list)
            # new_history_list contains [...history, {user: rich_prompt}, {assistant: response}]
            response_text, updated_history = generator.chat(text, history)
            
            # Since generator.chat already did the LLM call and returned history,
            # we just need to save the ONLY NEW messages to our storage.
            # However, during FIRST TURN, text is replaced by rich_prompt.
            
            # For simplicity: completely overwrite storage with updated_history
            # ContextStorage doesn't support overwrite easily, but we can clear and re-add.
            # Better: Modify ObsidianContextStorage to support set_context.
            
            # Actually, let's just use the updated_history and manually add to storage
            # Warning: first turn 'user' message in storage will be the RICH PROMPT
            # This is actually better for context continuity in Slack too.
            
            storage.clear()
            for msg in updated_history:
                storage.add_message(msg["role"], msg["content"])
                
            self._reply(channel_id, response_text, response_ts)
            
        except Exception as e:
            logger.error(f"Obsidian generation failed: {e}", exc_info=True)
            self._reply(channel_id, f"🐛 Error: {str(e)}", response_ts)

    def _reply(self, channel_id: str, text: str, ts: Optional[str] = None):
        from slack_bot.utils.mrkdwn import SlackFormatter

        # Slack API limits (official documentation):
        # - chat.postMessage: 40,000 chars
        # - chat.update: 4,000 chars
        # Slack markdown formatting can expand text by 50-100% (bold, links, code blocks, etc.)
        TRUNCATE_WARNING = "\n\n⚠️ (Response truncated, full text uploaded as file)"
        FILE_UPLOAD_HINT = "📄 Full response uploaded as file above ☝️"

        # Calculate safe pre-formatting limit with aggressive overhead buffer
        if ts:
            # For updates: 4000 limit - 60% overhead for safety = ~1600 chars
            max_raw_length = 1500
        else:
            # For new messages: 40000 limit - 40% overhead = ~24000 chars
            max_raw_length = 24000

        original_length = len(text)
        should_upload_file = original_length > max_raw_length

        if should_upload_file:
            # Upload full text as file first
            self._upload_as_file(channel_id, text, ts)

            # Then send a truncated preview
            truncate_at = text.rfind('\n\n', 0, 800)
            if truncate_at == -1 or truncate_at < 400:
                truncate_at = text.rfind('\n', 0, 800)
            if truncate_at == -1 or truncate_at < 400:
                truncate_at = 800

            preview_text = text[:truncate_at] + f"\n\n...\n\n{FILE_UPLOAD_HINT}"
            formatted_text = SlackFormatter.convert(preview_text)
            logger.info(f"Uploaded full response ({original_length} chars) as file, sending preview ({len(preview_text)} chars)")
        else:
            # Text is short enough, just format and send
            formatted_text = SlackFormatter.convert(text)

            # Final safety check after formatting
            final_limit = 3900 if ts else 39900
            if len(formatted_text) > final_limit:
                logger.warning(f"Formatted text ({len(formatted_text)} chars) exceeds limit after formatting. Uploading as file.")
                self._upload_as_file(channel_id, text, ts)
                # Send simple notification
                formatted_text = FILE_UPLOAD_HINT

        # Send the message
        try:
            if ts:
                self.client.chat_update(channel=channel_id, ts=ts, text=formatted_text)
            else:
                self.client.chat_postMessage(channel=channel_id, text=formatted_text)
        except Exception as e:
            if "msg_too_long" in str(e):
                logger.error(f"Still got msg_too_long error even after truncation. Text length: {len(formatted_text)}")
                # Ultimate fallback: send error message only
                try:
                    error_msg = "❌ Response formatting error. Please check the uploaded file above."
                    if ts:
                        self.client.chat_update(channel=channel_id, ts=ts, text=error_msg)
                    else:
                        self.client.chat_postMessage(channel=channel_id, text=error_msg)
                except:
                    logger.error("Failed to send even error message", exc_info=True)
            else:
                raise

    def _upload_as_file(self, channel_id: str, content: str, ts: Optional[str] = None):
        """Fallback: upload long responses as text files."""
        try:
            import tempfile
            from datetime import datetime

            filename = f"response_{datetime.now().strftime('%Y%m%d_%H%M%S')}.txt"

            with tempfile.NamedTemporaryFile(mode='w', suffix='.txt', delete=False, encoding='utf-8') as tmp:
                tmp.write(content)
                tmp_path = tmp.name

            self.client.files_upload_v2(
                channel=channel_id,
                file=tmp_path,
                filename=filename,
                initial_comment="📄 Response too long for Slack message, uploaded as file:",
                thread_ts=ts
            )

            os.unlink(tmp_path)
            logger.info(f"Uploaded long response as file: {filename}")
        except Exception as e:
            logger.error(f"Failed to upload file: {e}", exc_info=True)
            # Ultimate fallback: send error message
            error_msg = "❌ Response too long to display. Please try a more specific query."
            if ts:
                self.client.chat_update(channel=channel_id, ts=ts, text=error_msg)
            else:
                self.client.chat_postMessage(channel=channel_id, text=error_msg)