"""Bridge protocol — file-based communication between Discord bot and Antigravity.

Bridge directory: ~/.gemini/antigravity/bridge/
Structure:
  bridge/
    pending/     ← Bot writes approval requests for Discord
    response/    ← Bot writes user responses from Discord
    commands/    ← Bot writes user text input from Discord

Protocol:
1. VS Code Extension detects pending approval → writes JSON to pending/
2. Bot reads pending/ → sends Discord message with ✅/❌ buttons
3. User clicks button → Bot writes JSON to response/
4. VS Code Extension reads response/ → executes action
"""

import json
import time
import logging
from pathlib import Path
from dataclasses import dataclass, asdict
from enum import Enum

from config import Config

logger = logging.getLogger(__name__)


class ApprovalStatus(Enum):
    PENDING = "pending"
    APPROVED = "approved"
    REJECTED = "rejected"
    TIMEOUT = "timeout"


@dataclass
class ApprovalRequest:
    """An approval request from Antigravity."""
    request_id: str
    conversation_id: str
    command: str           # The command/action needing approval
    description: str       # Human-readable description
    timestamp: float
    status: str = "pending"
    discord_message_id: int = 0
    project_name: str = ""  # Project routing key


@dataclass
class UserResponse:
    """A user response from Discord."""
    request_id: str
    approved: bool
    user_input: str = ""
    timestamp: float = 0
    button_index: int = -1  # -1 = legacy (approve/reject), 0+ = specific button index
    step_type: str = ""  # pass through from pending for extension routing


class BridgeProtocol:
    """Manages the file-based bridge protocol."""

    def __init__(self):
        self.bridge_dir = Config.BRAIN_PATH.parent / "bridge"
        self.pending_dir = self.bridge_dir / "pending"
        self.response_dir = self.bridge_dir / "response"
        self.commands_dir = self.bridge_dir / "commands"

        # Create directories
        for d in [self.pending_dir, self.response_dir, self.commands_dir]:
            d.mkdir(parents=True, exist_ok=True)

        # Startup cleanup: purge stale pending files (> 5 min old)
        self._cleanup_stale_pending()

        logger.info(f"Bridge protocol initialized: {self.bridge_dir}")

    def _cleanup_stale_pending(self, max_age_seconds: int = 300):
        """Remove pending files older than max_age_seconds on startup."""
        now = time.time()
        cleaned = 0
        for f in self.pending_dir.glob("*.json"):
            try:
                data = json.loads(f.read_text(encoding="utf-8-sig"))
                ts = data.get("timestamp", 0)
                if now - ts > max_age_seconds:
                    f.unlink()
                    cleaned += 1
            except (json.JSONDecodeError, OSError):
                f.unlink()  # corrupt file, remove
                cleaned += 1
        if cleaned:
            logger.info(f"Startup cleanup: removed {cleaned} stale pending files")

    def get_pending_requests(self) -> list[ApprovalRequest]:
        """Read all pending approval requests. Skips files older than 30 minutes."""
        requests = []
        fields = {f.name for f in ApprovalRequest.__dataclass_fields__.values()}
        now = time.time()
        MAX_AGE = 1800  # 30 minutes (matches Discord button timeout)
        for f in self.pending_dir.glob("*.json"):
            try:
                data = json.loads(f.read_text(encoding="utf-8-sig"))
                ts = data.get("timestamp", 0)
                if now - ts > MAX_AGE:
                    # Too old — mark expired and skip
                    data["status"] = "expired"
                    f.write_text(
                        json.dumps(data, ensure_ascii=False, indent=2),
                        encoding="utf-8",
                    )
                    continue
                if data.get("status") == "pending":
                    # Filter to known fields only
                    filtered = {k: v for k, v in data.items() if k in fields}
                    requests.append(ApprovalRequest(**filtered))
            except (json.JSONDecodeError, TypeError, OSError) as e:
                logger.warning(f"Bad pending request {f.name}: {e}")
        return requests

    def read_pending_request(self, request_id: str) -> ApprovalRequest | None:
        """Re-read a specific pending request (to get merged data)."""
        f = self.pending_dir / f"{request_id}.json"
        if not f.exists():
            return None
        try:
            data = json.loads(f.read_text(encoding="utf-8-sig"))
            fields = {fn.name for fn in ApprovalRequest.__dataclass_fields__.values()}
            filtered = {k: v for k, v in data.items() if k in fields}
            return ApprovalRequest(**filtered)
        except (json.JSONDecodeError, TypeError, OSError):
            return None

    def write_response(self, response: UserResponse):
        """Write a user response to the response directory."""
        response.timestamp = time.time()
        filename = f"{response.request_id}.json"
        filepath = self.response_dir / filename

        filepath.write_text(
            json.dumps(asdict(response), ensure_ascii=False, indent=2),
            encoding="utf-8"
        )
        logger.info(f"Response written: {filename} (approved={response.approved})")

        # Delete pending file after processing (prevents re-processing and accumulation)
        pending_file = self.pending_dir / filename
        if pending_file.exists():
            try:
                pending_file.unlink()
            except OSError:
                pass

    def write_command(self, conversation_id: str, text: str, *, project_name: str = ""):
        """Write a user text command for Antigravity to consume."""
        cmd_id = f"{int(time.time() * 1000)}"
        filepath = self.commands_dir / f"{cmd_id}.json"

        data = {
            "id": cmd_id,
            "conversation_id": conversation_id,
            "project_name": project_name,
            "text": text,
            "timestamp": time.time(),
            "consumed": False,
        }

        filepath.write_text(
            json.dumps(data, ensure_ascii=False, indent=2),
            encoding="utf-8"
        )
        logger.info(f"Command written: {cmd_id} → project={project_name}")
        return cmd_id