"""Service responsible for executing workflows for WebSocket sessions."""

import logging
from pathlib import Path
from typing import List, Optional, Union

from check.check import load_config
from entity.graph_config import GraphConfig
from entity.messages import Message
from entity.enums import LogLevel
from utils.exceptions import ValidationError, WorkflowCancelledError
from utils.structured_logger import get_server_logger, LogType
from utils.task_input import TaskInputBuilder
from workflow.graph_context import GraphContext

from server.services.attachment_service import AttachmentService
from server.services.session_execution import SessionExecutionController
from server.services.session_store import SessionStatus, WorkflowSessionStore
from server.services.websocket_executor import WebSocketGraphExecutor
from server.services.workflow_storage import validate_workflow_filename
from server.settings import WARE_HOUSE_DIR, YAML_DIR


class WorkflowRunService:
    def __init__(
        self,
        session_store: WorkflowSessionStore,
        session_controller: SessionExecutionController,
        attachment_service: AttachmentService,
    ) -> None:
        self.session_store = session_store
        self.session_controller = session_controller
        self.attachment_service = attachment_service
        self.logger = logging.getLogger(__name__)

    def request_cancel(self, session_id: str, *, reason: Optional[str] = None) -> bool:
        session = self.session_store.get_session(session_id)
        if not session:
            return False

        cancel_message = reason or "Cancellation requested"
        session.cancel_reason = cancel_message
        if not session.cancel_event.is_set():
            session.cancel_event.set()
            self.logger.info("Cancellation requested for session %s", session_id)

        if session.executor:
            try:
                session.executor.request_cancel(cancel_message)
            except Exception as exc:
                self.logger.warning("Failed to propagate cancellation to executor for %s: %s", session_id, exc)

        self.session_store.update_session_status(session_id, SessionStatus.CANCELLED, error_message=cancel_message)
        return True

    async def start_workflow(
        self,
        session_id: str,
        yaml_file: str,
        task_prompt: str,
        websocket_manager,
        *,
        attachments: Optional[List[str]] = None,
        log_level: Optional[LogLevel] = None,
    ) -> None:
        normalized_yaml_name = (yaml_file or "").strip()
        try:
            yaml_path = self._resolve_yaml_path(normalized_yaml_name)
            normalized_yaml_name = yaml_path.name

            attachments = attachments or []
            if (not task_prompt or not task_prompt.strip()) and not attachments:
                raise ValidationError(
                    "Task prompt cannot be empty",
                    details={"task_prompt_provided": bool(task_prompt)},
                )

            self.attachment_service.prepare_session_workspace(session_id)
            self.session_store.create_session(
                yaml_file=normalized_yaml_name,
                task_prompt=task_prompt,
                session_id=session_id,
                attachments=attachments,
            )
            self.session_store.update_session_status(session_id, SessionStatus.RUNNING)

            await websocket_manager.send_message(
                session_id,
                {
                    "type": "workflow_started",
                    "data": {"yaml_file": normalized_yaml_name, "task_prompt": task_prompt},
                },
            )

            await self._execute_workflow_async(
                session_id,
                yaml_path,
                task_prompt,
                websocket_manager,
                attachments,
                log_level,
            )
        except ValidationError as exc:
            self.logger.error(str(exc))
            logger = get_server_logger()
            logger.error(
                "Workflow validation error",
                log_type=LogType.WORKFLOW,
                session_id=session_id,
                yaml_file=normalized_yaml_name,
                validation_details=getattr(exc, "details", None),
            )
            self.session_store.set_session_error(session_id, str(exc))
            await websocket_manager.send_message(
                session_id,
                {"type": "error", "data": {"message": str(exc)}},
            )
        except Exception as exc:
            self.logger.error(f"Error starting workflow for session {session_id}: {exc}")
            logger = get_server_logger()
            logger.log_exception(
                exc,
                "Error starting workflow",
                session_id=session_id,
                yaml_file=normalized_yaml_name,
            )
            self.session_store.set_session_error(session_id, str(exc))
            await websocket_manager.send_message(
                session_id,
                {
                    "type": "error",
                    "data": {"message": f"Failed to start workflow: {exc}"},
                },
            )

    async def _execute_workflow_async(
        self,
        session_id: str,
        yaml_path: Path,
        task_prompt: str,
        websocket_manager,
        attachments: List[str],
        log_level: LogLevel,
    ) -> None:
        session = self.session_store.get_session(session_id)
        cancel_event = session.cancel_event if session else None
        try:
            design = load_config(yaml_path)
            graph_config = GraphConfig.from_definition(
                design.graph,
                name=f"session_{session_id}",
                output_root=WARE_HOUSE_DIR,
                source_path=str(yaml_path),
                vars=design.vars,
            )
            if log_level:
                graph_config.log_level = log_level
                graph_config.definition.log_level = log_level
            graph_context = GraphContext(config=graph_config)

            executor = WebSocketGraphExecutor(
                graph_context,
                session_id,
                self.session_controller,
                self.attachment_service,
                websocket_manager,
                self.session_store,
                cancel_event=cancel_event,
            )

            if session:
                session.graph = graph_context
                session.executor = executor
                if session.cancel_event.is_set():
                    executor.request_cancel(session.cancel_reason or "Cancellation requested")

            task_input = self._build_initial_task_input(
                session_id,
                graph_context,
                task_prompt,
                attachments,
                executor.attachment_store,
            )

            await executor.execute_graph_async(task_input)

            # If cancellation was requested during execution but not raised inside threads,
            # treat the run as cancelled to avoid conflicting status.
            if cancel_event and cancel_event.is_set():
                reason = session.cancel_reason if session else "Cancellation requested"
                raise WorkflowCancelledError(reason, workflow_id=graph_context.name)

            results = executor.get_results()
            self.session_store.complete_session(session_id, results)

            await websocket_manager.send_message(
                session_id,
                {
                    "type": "workflow_completed",
                    "data": {
                        "results": results,
                        "summary": graph_context.final_message(),
                        "token_usage": executor.token_tracker.get_token_usage(),
                    },
                },
            )

            logger = get_server_logger()
            logger.info(
                "Workflow execution completed successfully",
                log_type=LogType.WORKFLOW,
                session_id=session_id,
                yaml_path=str(yaml_path),
                result_count=len(results) if isinstance(results, dict) else 0,
            )
        except WorkflowCancelledError as exc:
            reason = str(exc)
            self.session_store.update_session_status(session_id, SessionStatus.CANCELLED, error_message=reason)
            await websocket_manager.send_message(
                session_id,
                {
                    "type": "workflow_cancelled",
                    "data": {"message": reason},
                },
            )
            logger = get_server_logger()
            logger.info(
                "Workflow execution cancelled",
                log_type=LogType.WORKFLOW,
                session_id=session_id,
                yaml_path=str(yaml_path),
                cancellation_reason=reason,
            )
        except ValidationError as exc:
            self.session_store.set_session_error(session_id, str(exc))
            await websocket_manager.send_message(
                session_id,
                {"type": "error", "data": {"message": str(exc)}},
            )
            logger = get_server_logger()
            logger.error(
                "Workflow validation error",
                log_type=LogType.WORKFLOW,
                session_id=session_id,
                yaml_path=str(yaml_path),
                validation_details=getattr(exc, "details", None),
            )
        except Exception as exc:
            self.session_store.set_session_error(session_id, str(exc))
            await websocket_manager.send_message(
                session_id,
                {"type": "error", "data": {"message": f"Workflow execution error: {exc}"}},
            )
            logger = get_server_logger()
            logger.log_exception(
                exc,
                f"Error executing workflow for session {session_id}",
                session_id=session_id,
                yaml_path=str(yaml_path),
            )
        finally:
            session_ref = self.session_store.get_session(session_id)
            if session_ref:
                session_ref.executor = None
                session_ref.graph = None
            self.session_controller.cleanup_session(session_id)
            if session_id not in websocket_manager.active_connections:
                self.session_store.pop_session(session_id)

    def _build_initial_task_input(
        self,
        session_id: str,
        graph_context: GraphContext,
        prompt: str,
        attachment_ids: List[str],
        store,
    ) -> Union[List[Message], str]:
        if not attachment_ids:
            return prompt

        blocks = self.attachment_service.build_attachment_blocks(
            session_id,
            attachment_ids,
            target_store=store,
        )
        return TaskInputBuilder(store).build_from_blocks(prompt, blocks)

    def _resolve_yaml_path(self, yaml_filename: str) -> Path:
        """Validate and resolve YAML paths inside the configured directory."""

        safe_name = validate_workflow_filename(yaml_filename, require_yaml_extension=True)
        yaml_path = YAML_DIR / safe_name
        if not yaml_path.exists():
            raise ValidationError("YAML file not found", details={"yaml_file": safe_name})
        return yaml_path