"""
GUARDiA ITSM — AI 에이전트 관리 API

엔드포인트:
  GET    /api/agents                         에이전트 목록
  POST   /api/agents                         에이전트 생성
  GET    /api/agents/{id}                    에이전트 상세
  PATCH  /api/agents/{id}                    에이전트 수정
  DELETE /api/agents/{id}                    에이전트 삭제
  POST   /api/agents/{id}/heartbeat          수동 하트비트 실행
  POST   /api/agents/{id}/pause              일시 중지
  POST   /api/agents/{id}/resume             재개
  GET    /api/agents/{id}/tasks              태스크 목록
  POST   /api/agents/{id}/tasks              태스크 직접 생성 (Developer 에이전트용)
  GET    /api/agents/approvals               전체 승인 대기 목록
  PATCH  /api/agents/approvals/{id}/review   승인 또는 거부
  GET    /api/agents/stats                   전체 에이전트 통계
  GET    /api/agents/orgchart               조직도 반환 (Phase 4 대시보드용)
  GET    /api/agents/llm/health             Ollama 헬스체크
  GET    /api/agents/llm/models             설치된 모델 목록
  POST   /api/agents/llm/pull              모델 다운로드 시작

RBAC: CUSTOMER 역할 전체 차단.
"""
from __future__ import annotations

import logging
from datetime import datetime, date
from typing import Optional, List

from fastapi import APIRouter, Depends, HTTPException, status, BackgroundTasks
from sqlalchemy import select, func, and_
from sqlalchemy.ext.asyncio import AsyncSession

from database import get_db
from models import (
    User, UserRole,
    AgentConfig, AgentTask, AgentApproval,
    AgentRole, AgentStatus, LLMProvider, AgentTaskStatus, AgentApprovalStatus,
    AgentConfigOut, AgentConfigCreate, AgentConfigUpdate,
    AgentTaskOut, AgentTaskCreate,
    AgentApprovalOut, AgentApprovalReview,
    AgentStatsOut, AgentOrgNode,
)
from routers.auth import get_current_user

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/api/agents", tags=["agents"])


# ── 공통 헬퍼 ────────────────────────────────────────────────────────────────

def _check_access(user: User) -> None:
    if user.role == UserRole.CUSTOMER:
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="에이전트 관리는 운영 계정만 접근 가능합니다.",
        )


async def _get_agent_or_404(agent_id: int, db: AsyncSession) -> AgentConfig:
    agent = (await db.execute(
        select(AgentConfig).where(AgentConfig.id == agent_id)
    )).scalars().first()
    if not agent:
        raise HTTPException(status_code=404, detail=f"에이전트 ID {agent_id} 없음")
    return agent


# ── 에이전트 CRUD ────────────────────────────────────────────────────────────

@router.get("", response_model=List[AgentConfigOut])
async def list_agents(
    role: Optional[str] = None,
    active_only: bool = False,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """에이전트 목록 조회."""
    _check_access(current_user)
    q = select(AgentConfig)
    if role:
        q = q.where(AgentConfig.role == role)
    if active_only:
        q = q.where(AgentConfig.is_active.is_(True))
    q = q.order_by(AgentConfig.role, AgentConfig.name)
    return (await db.execute(q)).scalars().all()


@router.post("", response_model=AgentConfigOut, status_code=status.HTTP_201_CREATED)
async def create_agent(
    body: AgentConfigCreate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """에이전트 등록."""
    _check_access(current_user)
    if current_user.role not in (UserRole.ADMIN, UserRole.PM):
        raise HTTPException(status_code=403, detail="에이전트 생성은 ADMIN/PM만 가능합니다.")

    agent = AgentConfig(
        name=body.name,
        role=body.role,
        description=body.description,
        llm_provider=body.llm_provider,
        llm_model=body.llm_model,
        system_prompt=body.system_prompt,
        heartbeat_cron=body.heartbeat_cron,
        is_active=body.is_active,
        status=AgentStatus.IDLE,
        created_by=current_user.id,
    )
    db.add(agent)
    await db.commit()
    await db.refresh(agent)

    # 하트비트 크론 등록 (APScheduler)
    if agent.heartbeat_cron:
        _register_heartbeat(agent)

    logger.info("에이전트 생성: id=%d role=%s user=%s", agent.id, agent.role, current_user.username)
    return agent


@router.get("/stats", response_model=AgentStatsOut)
async def get_stats(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """에이전트 전체 통계 — Phase 4 대시보드용."""
    _check_access(current_user)

    total = (await db.execute(select(func.count()).select_from(AgentConfig))).scalar() or 0
    active = (await db.execute(
        select(func.count()).select_from(AgentConfig).where(AgentConfig.is_active.is_(True))
    )).scalar() or 0

    today_start = datetime.combine(date.today(), datetime.min.time())
    tasks_today = (await db.execute(
        select(func.count()).select_from(AgentTask)
        .where(AgentTask.created_at >= today_start)
    )).scalar() or 0

    tokens_today = (await db.execute(
        select(func.coalesce(func.sum(AgentTask.tokens_used), 0))
        .where(AgentTask.created_at >= today_start)
    )).scalar() or 0

    pending_approvals = (await db.execute(
        select(func.count()).select_from(AgentApproval)
        .where(AgentApproval.status == AgentApprovalStatus.PENDING)
    )).scalar() or 0

    from core.llm_client import get_llm_client
    llm_online = await get_llm_client().health_check()

    return AgentStatsOut(
        total_agents=total,
        active_agents=active,
        total_tasks_today=tasks_today,
        total_tokens_today=tokens_today,
        pending_approvals=pending_approvals,
        llm_online=llm_online,
    )


@router.get("/orgchart", response_model=List[AgentOrgNode])
async def get_orgchart(
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """에이전트 조직도 — Phase 4 대시보드용."""
    _check_access(current_user)

    agents = (await db.execute(
        select(AgentConfig).where(AgentConfig.is_active.is_(True))
    )).scalars().all()

    # 조직 계층: CEO → CTO/PM_AGENT → DEV/QA
    hierarchy = {
        AgentRole.CEO:             [],
        AgentRole.CTO:             [AgentRole.DEVELOPER, AgentRole.QA],
        AgentRole.PM_AGENT:        [],
        AgentRole.DEVELOPER:       [],
        AgentRole.QA:              [],
        AgentRole.INCIDENT_TRIAGE: [],
        AgentRole.KB_CURATOR:      [],
        AgentRole.SSL_WATCHER:     [],
        AgentRole.WBS_MONITOR:     [],
        AgentRole.PM_SUGGESTER:    [],
    }
    ceo_children = [AgentRole.CTO, AgentRole.PM_AGENT,
                    AgentRole.INCIDENT_TRIAGE, AgentRole.KB_CURATOR,
                    AgentRole.SSL_WATCHER, AgentRole.WBS_MONITOR, AgentRole.PM_SUGGESTER]

    def build_node(a: AgentConfig) -> AgentOrgNode:
        child_roles = hierarchy.get(a.role, [])
        child_agents = [x for x in agents if x.role in [r.value for r in child_roles]]
        return AgentOrgNode(
            id=a.id,
            name=a.name,
            role=a.role,
            status=a.status,
            children=[build_node(c) for c in child_agents],
        )

    ceo_agents = [a for a in agents if a.role == AgentRole.CEO]
    return [build_node(a) for a in ceo_agents] if ceo_agents else [
        AgentOrgNode(id=0, name="(CEO 미등록)", role="CEO", status="IDLE")
    ]


@router.get("/approvals", response_model=List[AgentApprovalOut])
async def list_approvals(
    pending_only: bool = True,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """승인 대기 목록."""
    _check_access(current_user)
    q = select(AgentApproval).order_by(AgentApproval.requested_at.desc())
    if pending_only:
        q = q.where(AgentApproval.status == AgentApprovalStatus.PENDING)
    return (await db.execute(q.limit(50))).scalars().all()


@router.patch("/approvals/{approval_id}/review", response_model=AgentApprovalOut)
async def review_approval(
    approval_id: int,
    body: AgentApprovalReview,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """승인 또는 거부."""
    _check_access(current_user)
    approval = (await db.execute(
        select(AgentApproval).where(AgentApproval.id == approval_id)
    )).scalars().first()
    if not approval:
        raise HTTPException(status_code=404, detail="승인 항목 없음")
    if approval.status != AgentApprovalStatus.PENDING:
        raise HTTPException(status_code=400, detail="이미 처리된 항목입니다.")

    approval.status = (
        AgentApprovalStatus.APPROVED if body.approved else AgentApprovalStatus.REJECTED
    )
    approval.notes = body.notes
    approval.reviewed_by = current_user.id
    approval.reviewed_at = datetime.now()
    await db.commit()
    await db.refresh(approval)

    logger.info(
        "승인 처리: approval_id=%d status=%s user=%s",
        approval_id, approval.status, current_user.username,
    )
    return approval


# ── LLM 헬스·모델 관리 ────────────────────────────────────────────────────

@router.get("/llm/health")
async def llm_health(current_user: User = Depends(get_current_user)):
    """Ollama 서버 상태 확인."""
    _check_access(current_user)
    from core.llm_client import get_llm_client
    client = get_llm_client()
    online = await client.health_check()
    models = await client.list_models() if online else []
    return {
        "online": online,
        "base_url": client.base_url,
        "models": [{"name": m.name, "size_gb": round(m.size / 1e9, 1)} for m in models],
    }


@router.post("/llm/pull")
async def pull_model(
    model: str,
    background_tasks: BackgroundTasks,
    current_user: User = Depends(get_current_user),
):
    """Ollama 모델 다운로드 (백그라운드)."""
    _check_access(current_user)
    if current_user.role != UserRole.ADMIN:
        raise HTTPException(status_code=403, detail="모델 다운로드는 ADMIN만 가능합니다.")

    from core.llm_client import get_llm_client
    background_tasks.add_task(get_llm_client().pull_model, model)
    return {"message": f"모델 '{model}' 다운로드 시작 (백그라운드)", "model": model}


# ── 에이전트 상세·수정·삭제 ───────────────────────────────────────────────

@router.get("/{agent_id}", response_model=AgentConfigOut)
async def get_agent(
    agent_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    _check_access(current_user)
    return await _get_agent_or_404(agent_id, db)


@router.patch("/{agent_id}", response_model=AgentConfigOut)
async def update_agent(
    agent_id: int,
    body: AgentConfigUpdate,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    _check_access(current_user)
    agent = await _get_agent_or_404(agent_id, db)
    for k, v in body.model_dump(exclude_none=True).items():
        setattr(agent, k, v)
    await db.commit()
    await db.refresh(agent)
    return agent


@router.delete("/{agent_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_agent(
    agent_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    if current_user.role != UserRole.ADMIN:
        raise HTTPException(status_code=403, detail="ADMIN만 에이전트 삭제 가능합니다.")
    agent = await _get_agent_or_404(agent_id, db)
    await db.delete(agent)
    await db.commit()


# ── 하트비트·제어 ────────────────────────────────────────────────────────────

@router.post("/{agent_id}/heartbeat")
async def manual_heartbeat(
    agent_id: int,
    background_tasks: BackgroundTasks,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """수동 하트비트 트리거 (즉시 실행, 백그라운드)."""
    _check_access(current_user)
    agent = await _get_agent_or_404(agent_id, db)
    if not agent.is_active:
        raise HTTPException(status_code=400, detail="비활성 에이전트입니다.")

    from core.agents import get_agent_engine
    background_tasks.add_task(get_agent_engine().run_heartbeat, agent_id)
    return {"message": f"에이전트 '{agent.name}' 하트비트 시작", "agent_id": agent_id}


@router.post("/{agent_id}/pause")
async def pause_agent(
    agent_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """에이전트 일시 중지."""
    _check_access(current_user)
    agent = await _get_agent_or_404(agent_id, db)
    agent.is_active = False
    agent.status = AgentStatus.PAUSED
    await db.commit()
    return {"message": f"에이전트 '{agent.name}' 일시 중지", "status": "PAUSED"}


@router.post("/{agent_id}/resume")
async def resume_agent(
    agent_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """에이전트 재개."""
    _check_access(current_user)
    agent = await _get_agent_or_404(agent_id, db)
    agent.is_active = True
    agent.status = AgentStatus.IDLE
    await db.commit()
    return {"message": f"에이전트 '{agent.name}' 재개", "status": "IDLE"}


# ── 태스크 ───────────────────────────────────────────────────────────────────

@router.get("/{agent_id}/tasks", response_model=List[AgentTaskOut])
async def list_tasks(
    agent_id: int,
    limit: int = 20,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    _check_access(current_user)
    tasks = (await db.execute(
        select(AgentTask)
        .where(AgentTask.agent_id == agent_id)
        .order_by(AgentTask.created_at.desc())
        .limit(limit)
    )).scalars().all()
    return tasks


@router.post("/{agent_id}/tasks", response_model=AgentTaskOut,
             status_code=status.HTTP_201_CREATED)
async def create_task(
    agent_id: int,
    body: AgentTaskCreate,
    background_tasks: BackgroundTasks,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """Developer 에이전트에게 태스크 직접 등록."""
    _check_access(current_user)
    agent = await _get_agent_or_404(agent_id, db)

    task = AgentTask(
        agent_id=agent_id,
        title=body.title,
        description=body.description,
        status=AgentTaskStatus.PENDING,
        input_data=body.input_data,
        created_at=datetime.now(),
    )
    db.add(task)
    await db.commit()
    await db.refresh(task)

    # Developer 에이전트면 바로 하트비트 실행
    if agent.role == AgentRole.DEVELOPER and agent.is_active:
        from core.agents import get_agent_engine
        background_tasks.add_task(get_agent_engine().run_heartbeat, agent_id)

    return task


# ── 스케줄러 등록 헬퍼 ────────────────────────────────────────────────────

def _register_heartbeat(agent: AgentConfig) -> None:
    """APScheduler에 에이전트 하트비트 크론 잡 등록."""
    try:
        from core.scheduler import get_scheduler
        from apscheduler.triggers.cron import CronTrigger

        scheduler = get_scheduler()
        if scheduler is None or not scheduler.running:
            return

        from core.agents import get_agent_engine
        job_id = f"agent_heartbeat_{agent.id}"

        scheduler.add_job(
            get_agent_engine().run_heartbeat,
            CronTrigger.from_crontab(agent.heartbeat_cron, timezone="Asia/Seoul"),
            args=[agent.id],
            id=job_id,
            name=f"에이전트 하트비트: {agent.name}",
            replace_existing=True,
            misfire_grace_time=300,
        )
        logger.info("에이전트 하트비트 등록: job_id=%s cron=%s", job_id, agent.heartbeat_cron)
    except Exception as exc:
        logger.warning("에이전트 하트비트 스케줄 등록 실패: %s", exc)


# ── 에이전트 간 메시지 API (Priority 3) ───────────────────────────────────────

@router.get("/{agent_id}/messages", summary="수신 메시지 목록")
async def get_agent_messages(
    agent_id: int,
    unread_only: bool = False,
    limit: int = 50,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """에이전트가 수신한 메시지 목록을 반환한다."""
    _check_access(current_user)
    from models import AgentMessage, AgentMessageOut
    q = select(AgentMessage).where(AgentMessage.to_agent_id == agent_id)
    if unread_only:
        q = q.where(AgentMessage.is_read.is_(False))
    q = q.order_by(AgentMessage.created_at.desc()).limit(limit)
    msgs = (await db.execute(q)).scalars().all()
    return [AgentMessageOut.model_validate(m) for m in msgs]


@router.post("/{agent_id}/messages", status_code=201, summary="메시지 전송")
async def send_agent_message(
    agent_id: int,
    payload: dict,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    에이전트에게 메시지를 전송한다.

    Body: {
        "from_agent_id": int | null,
        "message_type": "TASK_DELEGATION|STATUS_UPDATE|ESCALATION",
        "subject": "string",
        "body": "string",
        "metadata_json": "string"
    }
    """
    _check_access(current_user)
    from models import AgentMessage, AgentMessageOut

    msg = AgentMessage(
        from_agent_id=payload.get("from_agent_id"),
        to_agent_id=agent_id,
        message_type=payload.get("message_type", "STATUS_UPDATE"),
        subject=payload.get("subject", ""),
        body=payload.get("body"),
        metadata_json=payload.get("metadata_json"),
    )
    db.add(msg)
    await db.commit()
    await db.refresh(msg)
    return AgentMessageOut.model_validate(msg)


@router.patch("/messages/{msg_id}/read", summary="메시지 읽음 처리")
async def mark_message_read(
    msg_id: int,
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """메시지를 읽음 처리한다."""
    _check_access(current_user)
    from models import AgentMessage, AgentMessageOut

    msg = await db.get(AgentMessage, msg_id)
    if not msg:
        raise HTTPException(404, "메시지를 찾을 수 없습니다.")
    msg.is_read = True
    msg.read_at = datetime.utcnow()
    await db.commit()
    await db.refresh(msg)
    return AgentMessageOut.model_validate(msg)


# ── 파인튜닝 API (Priority 3) ─────────────────────────────────────────────────

@router.post("/finetune/start", summary="파인튜닝 시작 (ADMIN only)")
async def start_finetune(
    background_tasks: BackgroundTasks,
    payload: dict = {},
    db: AsyncSession = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    tb_agent_task(COMPLETED) 데이터로 Ollama 커스텀 모델 파인튜닝을 시작한다.

    Body: { "model_name": "guardia-agent-v2", "limit": 1000 }
    """
    if current_user.role != UserRole.ADMIN:
        raise HTTPException(403, "ADMIN 권한이 필요합니다.")

    import os
    model_name = payload.get("model_name", "guardia-agent-v2")
    limit = int(payload.get("limit", 1000))
    dataset_path = f"/opt/guardia/finetune/{model_name}.jsonl"

    async def _run_finetune():
        from core.llm_client import get_llm_client
        llm = get_llm_client()
        count = await llm.export_finetune_dataset(dataset_path, limit=limit)
        if count == 0:
            logger.error("[finetune] 데이터셋 내보내기 실패 또는 데이터 없음")
            return
        ok = await llm.fine_tune(dataset_path, model_name)
        if ok:
            logger.info("[finetune] 파인튜닝 완료: model=%s", model_name)
        else:
            logger.error("[finetune] 파인튜닝 실패: model=%s", model_name)

    background_tasks.add_task(_run_finetune)
    return {"status": "started", "model_name": model_name, "dataset_path": dataset_path}


@router.get("/finetune/status", summary="파인튜닝 진행 상태 조회")
async def get_finetune_status(
    current_user: User = Depends(get_current_user),
):
    """파인튜닝 진행 상태를 반환한다 (Ollama 모델 목록 기반)."""
    _check_access(current_user)
    from core.llm_client import get_llm_client
    llm = get_llm_client()
    models = await llm.list_models()
    return {"models": [{"name": m.name, "size": m.size} for m in models]}