import time
from datetime import datetime
from typing import Any

from sqlalchemy.ext.asyncio import AsyncSession

from app.models import Agent, Workflow, WorkflowRun
from app.services.llm import LLMService


class WorkflowService:
    def __init__(self, db: AsyncSession):
        self.db = db
        self.llm = LLMService(db)

    async def run(self, workflow: Workflow, inputs: dict[str, Any]) -> WorkflowRun:
        started = time.time()
        definition = workflow.published_definition or workflow.definition or {}
        run = WorkflowRun(
            workflow_id=workflow.id,
            status="running",
            inputs=inputs,
            outputs={},
            execution_log=[],
            started_at=datetime.utcnow(),
        )
        self.db.add(run)
        await self.db.flush()

        variables: dict[str, Any] = dict(inputs)
        log: list[dict[str, Any]] = []
        try:
            nodes = definition.get("nodes") or []
            for node in nodes:
                node_type = node.get("type", "unknown")
                node_id = node.get("id", node_type)
                data = node.get("data") or {}
                entry = {"node_id": node_id, "node_type": node_type, "status": "completed"}
                if node_type == "start":
                    entry["output"] = variables
                elif node_type == "llm":
                    agent_id = data.get("agent_id")
                    prompt = data.get("prompt") or inputs.get("task") or inputs.get("message") or ""
                    agent = await self.db.get(Agent, agent_id) if agent_id else None
                    if agent:
                        result = await self.llm.complete(agent, prompt)
                    else:
                        result = f"LLM 节点占位输出：{prompt}"
                    variables[node_id] = result
                    entry["output"] = result
                elif node_type == "agent":
                    agent_id = data.get("agent_id")
                    agent = await self.db.get(Agent, agent_id) if agent_id else None
                    task = data.get("task") or inputs.get("task") or inputs.get("message") or ""
                    result = await self.llm.complete(agent, task) if agent else f"Agent 节点占位输出：{task}"
                    variables[node_id] = result
                    entry["output"] = result
                elif node_type == "condition":
                    entry["output"] = {"matched": True}
                elif node_type in {"parallel", "merge", "tool", "http"}:
                    entry["output"] = f"{node_type} 节点已执行最小占位逻辑"
                elif node_type == "end":
                    entry["output"] = variables
                else:
                    entry["status"] = "skipped"
                    entry["output"] = "未知节点类型，已跳过"
                log.append(entry)

            run.status = "completed"
            run.outputs = {"result": variables}
            run.execution_log = log
            workflow.run_count = (workflow.run_count or 0) + 1
        except Exception as exc:
            run.status = "failed"
            run.error_message = str(exc)
            run.execution_log = log
        finally:
            run.elapsed_time = int((time.time() - started) * 1000)
            run.completed_at = datetime.utcnow()
            await self.db.commit()
            await self.db.refresh(run)
        return run