from datetime import datetime
import asyncpg
from fastapi import APIRouter, Depends, HTTPException, Query, status
from sqlalchemy import and_, desc, select
from sqlalchemy.ext.asyncio import AsyncSession
from app.core.db import get_db
from app.core.deps import get_current_user, require_roles
from app.models.models import Metric, QueryStat, Target, User
from app.schemas.metric import MetricOut, QueryStatOut
from app.schemas.overview import DatabaseOverviewOut
from app.schemas.target import TargetCreate, TargetOut, TargetUpdate
from app.services.audit import write_audit_log
from app.services.collector import build_target_dsn
from app.services.crypto import encrypt_secret
from app.services.overview_service import get_target_overview

router = APIRouter()


@router.get("", response_model=list[TargetOut])
async def list_targets(user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)) -> list[TargetOut]:
    targets = (await db.scalars(select(Target).order_by(Target.id.desc()))).all()
    return [TargetOut.model_validate(item) for item in targets]


@router.post("", response_model=TargetOut, status_code=status.HTTP_201_CREATED)
async def create_target(
    payload: TargetCreate,
    user: User = Depends(require_roles("admin", "operator")),
    db: AsyncSession = Depends(get_db),
) -> TargetOut:
    target = Target(
        name=payload.name,
        host=payload.host,
        port=payload.port,
        dbname=payload.dbname,
        username=payload.username,
        encrypted_password=encrypt_secret(payload.password),
        sslmode=payload.sslmode,
        tags=payload.tags,
    )
    db.add(target)
    await db.commit()
    await db.refresh(target)
    await write_audit_log(db, "target.create", user.id, {"target_id": target.id, "name": target.name})
    return TargetOut.model_validate(target)


@router.get("/{target_id}", response_model=TargetOut)
async def get_target(target_id: int, user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)) -> TargetOut:
    target = await db.scalar(select(Target).where(Target.id == target_id))
    if not target:
        raise HTTPException(status_code=404, detail="Target not found")
    return TargetOut.model_validate(target)


@router.put("/{target_id}", response_model=TargetOut)
async def update_target(
    target_id: int,
    payload: TargetUpdate,
    user: User = Depends(require_roles("admin", "operator")),
    db: AsyncSession = Depends(get_db),
) -> TargetOut:
    target = await db.scalar(select(Target).where(Target.id == target_id))
    if not target:
        raise HTTPException(status_code=404, detail="Target not found")

    updates = payload.model_dump(exclude_unset=True)
    if "password" in updates:
        target.encrypted_password = encrypt_secret(updates.pop("password"))
    for key, value in updates.items():
        setattr(target, key, value)
    await db.commit()
    await db.refresh(target)
    await write_audit_log(db, "target.update", user.id, {"target_id": target.id})
    return TargetOut.model_validate(target)


@router.delete("/{target_id}")
async def delete_target(
    target_id: int,
    user: User = Depends(require_roles("admin", "operator")),
    db: AsyncSession = Depends(get_db),
) -> dict:
    target = await db.scalar(select(Target).where(Target.id == target_id))
    if not target:
        raise HTTPException(status_code=404, detail="Target not found")
    await db.delete(target)
    await db.commit()
    await write_audit_log(db, "target.delete", user.id, {"target_id": target_id})
    return {"status": "deleted"}


@router.get("/{target_id}/metrics", response_model=list[MetricOut])
async def get_metrics(
    target_id: int,
    metric: str = Query(...),
    from_ts: datetime = Query(alias="from"),
    to_ts: datetime = Query(alias="to"),
    user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
) -> list[MetricOut]:
    _ = user
    rows = (
        await db.scalars(
            select(Metric).where(
                and_(Metric.target_id == target_id, Metric.metric_name == metric, Metric.ts >= from_ts, Metric.ts <= to_ts)
            ).order_by(Metric.ts.asc())
        )
    ).all()
    return [MetricOut(ts=r.ts, metric_name=r.metric_name, value=r.value, labels=r.labels) for r in rows]


async def _live_conn(target: Target) -> asyncpg.Connection:
    return await asyncpg.connect(dsn=build_target_dsn(target))


@router.get("/{target_id}/locks")
async def get_locks(target_id: int, user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)) -> list[dict]:
    _ = user
    target = await db.scalar(select(Target).where(Target.id == target_id))
    if not target:
        raise HTTPException(status_code=404, detail="Target not found")
    conn = await _live_conn(target)
    try:
        rows = await conn.fetch(
            """
            SELECT locktype, mode, granted, relation::regclass::text AS relation, pid
            FROM pg_locks
            ORDER BY granted ASC, mode
            LIMIT 500
            """
        )
        return [dict(r) for r in rows]
    finally:
        await conn.close()


@router.get("/{target_id}/activity")
async def get_activity(target_id: int, user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)) -> list[dict]:
    _ = user
    target = await db.scalar(select(Target).where(Target.id == target_id))
    if not target:
        raise HTTPException(status_code=404, detail="Target not found")
    conn = await _live_conn(target)
    try:
        rows = await conn.fetch(
            """
            SELECT pid, usename, application_name, client_addr::text, state, wait_event_type, wait_event, now() - query_start AS running_for, left(query, 300) AS query
            FROM pg_stat_activity
            WHERE datname = current_database()
            ORDER BY query_start NULLS LAST
            LIMIT 200
            """
        )
        return [dict(r) for r in rows]
    finally:
        await conn.close()


@router.get("/{target_id}/top-queries", response_model=list[QueryStatOut])
async def get_top_queries(target_id: int, user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)) -> list[QueryStatOut]:
    _ = user
    rows = (
        await db.scalars(
            select(QueryStat)
            .where(QueryStat.target_id == target_id)
            .order_by(desc(QueryStat.ts))
            .limit(100)
        )
    ).all()
    return [
        QueryStatOut(
            ts=r.ts,
            queryid=r.queryid,
            calls=r.calls,
            total_time=r.total_time,
            mean_time=r.mean_time,
            rows=r.rows,
            query_text=r.query_text,
        )
        for r in rows
    ]


@router.get("/{target_id}/overview", response_model=DatabaseOverviewOut)
async def get_overview(target_id: int, user: User = Depends(get_current_user), db: AsyncSession = Depends(get_db)) -> DatabaseOverviewOut:
    _ = user
    target = await db.scalar(select(Target).where(Target.id == target_id))
    if not target:
        raise HTTPException(status_code=404, detail="Target not found")
    return await get_target_overview(target)