from __future__ import annotations

import os
import subprocess
import sys

from datetime import datetime

from fastapi import APIRouter, Depends, HTTPException, Query, Request, status
from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.core.config import ROOT_DIR
from app.core.security import get_current_user
from app.db.session import get_db
from app.models.system_log import AuditLog, SystemLog
from app.models.user import User
from app.services.persistent_logs import record_audit_log, record_system_log
from app.services.system_control import (
    build_task_id,
    clear_active_task_id,
    get_active_task_id,
    get_allowed_command,
    get_runner_script_path,
    is_task_stale,
    get_task_logs,
    require_super_admin,
    serialize_task,
    set_active_task_id,
    upsert_task_state,
)
from app.services.system_logs import (
    DEFAULT_LOG_LINE_LIMIT,
    MAX_LOG_LINE_LIMIT,
    SUPPORTED_LOG_LEVELS,
    append_buffer_log,
    list_log_sources,
    normalize_log_level,
    read_log_snapshot,
)
from app.services.earth_layer_cache import earth_layer_cache

router = APIRouter()


class RestartTaskCreate(BaseModel):
    action: str


class RestartTaskResponse(BaseModel):
    task_id: str
    action: str
    status: str
    stage: str
    message: str
    created_at: str
    updated_at: str
    requested_by: dict[str, object] | None = None


class RestartTaskLogsResponse(BaseModel):
    task_id: str
    lines: list[str]


class SystemLogSourceSummary(BaseModel):
    source_id: str
    name: str
    kind: str
    location: str
    description: str
    category: str
    status: str


class SystemLogSourcesResponse(BaseModel):
    items: list[SystemLogSourceSummary]


class SystemLogDailyMarker(BaseModel):
    date_token: str
    total: int
    dominant_level: str


class SystemLogSnapshotResponse(BaseModel):
    source_id: str
    name: str
    kind: str
    location: str
    description: str
    category: str
    status: str
    level: str
    selected_levels: list[str] = []
    search_query: str = ""
    available_levels: list[str]
    daily_markers: list[SystemLogDailyMarker] = []
    line_limit: int
    line_count: int
    lines: list[str]


class EarthClientLogEventCreate(BaseModel):
    level: str = "error"
    message: str
    category: str | None = None
    url: str | None = None
    module: str | None = None
    detail: str | None = None


class EarthClientLogEventResponse(BaseModel):
    accepted: bool
    source_id: str
    level: str


class EarthLayerCacheStatusResponse(BaseModel):
    prefix: str
    key_count: int
    memory_bytes: int
    layers: dict[str, dict[str, int]]


class EarthLayerCacheClearResponse(BaseModel):
    deleted: int


def ensure_super_admin(current_user: User) -> None:
    if not require_super_admin(current_user.role):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Only super_admin can restart services",
        )


def validate_log_date(raw_value: str | None, field_name: str) -> str | None:
    if raw_value in {None, ""}:
        return None
    try:
        return datetime.strptime(raw_value, "%Y-%m-%d").date().isoformat()
    except ValueError as exc:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"{field_name} must be in YYYY-MM-DD format",
        ) from exc


@router.get("/cache/earth-layers", response_model=EarthLayerCacheStatusResponse)
async def get_earth_layer_cache_status(
    current_user: User = Depends(get_current_user),
):
    ensure_super_admin(current_user)
    try:
        return earth_layer_cache.status()
    except Exception as exc:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail=f"Unable to read Earth layer cache status: {exc}",
        ) from exc


@router.delete("/cache/earth-layers", response_model=EarthLayerCacheClearResponse)
async def clear_earth_layer_cache(
    current_user: User = Depends(get_current_user),
):
    ensure_super_admin(current_user)
    try:
        return {"deleted": earth_layer_cache.delete_pattern()}
    except Exception as exc:
        raise HTTPException(
            status_code=status.HTTP_503_SERVICE_UNAVAILABLE,
            detail=f"Unable to clear Earth layer cache: {exc}",
        ) from exc


@router.post("/restart-tasks", response_model=RestartTaskResponse)
async def create_restart_task(
    payload: RestartTaskCreate,
    request: Request,
    current_user: User = Depends(get_current_user),
):
    ensure_super_admin(current_user)

    command = get_allowed_command(payload.action)
    if command is None:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail="Unsupported system action",
        )

    active_task_id = get_active_task_id()
    if active_task_id:
        active_task = serialize_task(active_task_id)
        if active_task and is_task_stale(active_task):
            upsert_task_state(
                active_task_id,
                status="failed",
                stage="failed",
                message="Previous restart task became stale and was released",
            )
            clear_active_task_id(active_task_id)
        elif active_task and active_task.get("status") in {"queued", "running"}:
            raise HTTPException(
                status_code=status.HTTP_409_CONFLICT,
                detail="Another restart task is already in progress",
            )

    task_id = build_task_id()
    requested_by = {"id": current_user.id, "username": current_user.username}
    task_state = upsert_task_state(
        task_id,
        action=payload.action,
        status="queued",
        stage="accepted",
        message="Restart task accepted",
        requested_by=requested_by,
    )
    set_active_task_id(task_id)

    env = os.environ.copy()
    backend_path = str(ROOT_DIR / "backend")
    existing_pythonpath = env.get("PYTHONPATH", "")
    env["PYTHONPATH"] = (
        f"{backend_path}{os.pathsep}{existing_pythonpath}"
        if existing_pythonpath
        else backend_path
    )

    try:
        subprocess.Popen(
            [
                sys.executable,
                str(get_runner_script_path()),
                "--task-id",
                task_id,
                "--action",
                payload.action,
            ],
            cwd=str(ROOT_DIR),
            env=env,
            stdout=subprocess.DEVNULL,
            stderr=subprocess.DEVNULL,
            start_new_session=True,
        )
    except OSError as exc:
        task_state = upsert_task_state(
            task_id,
            action=payload.action,
            status="failed",
            stage="failed",
            message=f"Unable to start restart runner: {exc}",
            requested_by=requested_by,
        )
        clear_active_task_id(task_id)
        await record_audit_log(
            action="system.restart_task.requested",
            actor_id=current_user.id,
            actor_name=current_user.username,
            target_type="restart_task",
            target_id=task_id,
            result="failed",
            ip=request.client.host if request.client else None,
            details={"action": payload.action, "message": task_state["message"]},
        )
        raise HTTPException(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            detail=task_state["message"],
        ) from exc

    await record_audit_log(
        action="system.restart_task.requested",
        actor_id=current_user.id,
        actor_name=current_user.username,
        target_type="restart_task",
        target_id=task_id,
        result="accepted",
        ip=request.client.host if request.client else None,
        details={"action": payload.action},
    )
    return task_state


@router.get("/restart-tasks/{task_id}", response_model=RestartTaskResponse)
async def get_restart_task(
    task_id: str,
    current_user: User = Depends(get_current_user),
):
    ensure_super_admin(current_user)

    task = serialize_task(task_id)
    if task is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Restart task not found")
    return task


@router.get("/restart-tasks/{task_id}/logs", response_model=RestartTaskLogsResponse)
async def get_restart_task_logs(
    task_id: str,
    current_user: User = Depends(get_current_user),
):
    ensure_super_admin(current_user)

    task = serialize_task(task_id)
    if task is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Restart task not found")
    return {"task_id": task_id, "lines": get_task_logs(task_id)}


@router.get("/logs/sources", response_model=SystemLogSourcesResponse)
async def get_system_log_sources(
    current_user: User = Depends(get_current_user),
):
    ensure_super_admin(current_user)
    return {
        "items": [
            *list_log_sources(),
            {
                "source_id": "system-db",
                "name": "系统事件",
                "kind": "database",
                "location": "table://system_logs",
                "description": "后端持久化系统事件、AI 和采集器操作日志。",
                "category": "database",
                "status": "ok",
            },
            {
                "source_id": "audit-db",
                "name": "审计事件",
                "kind": "database",
                "location": "table://audit_logs",
                "description": "管理员敏感操作和密钥 reveal 审计记录。",
                "category": "audit",
                "status": "ok",
            },
        ]
    }


async def read_database_log_snapshot(
    source_id: str,
    *,
    limit: int,
    level: str,
    levels: str | None,
    start_date: str | None,
    end_date: str | None,
    search: str | None,
    db: AsyncSession,
) -> dict | None:
    selected_levels = set(normalize_log_level(item) for item in (levels or level).split(",") if item.strip())
    selected_levels.discard("all")
    search_query = (search or "").strip().lower()
    lines: list[str] = []

    if source_id == "system-db":
        query = select(SystemLog).order_by(SystemLog.occurred_at.desc().nullslast(), SystemLog.id.desc()).limit(limit * 5)
        result = await db.execute(query)
        records = result.scalars().all()
        for record in records:
            record_level = normalize_log_level(record.level)
            if selected_levels and record_level not in selected_levels:
                continue
            occurred_at = record.occurred_at.date().isoformat() if record.occurred_at else ""
            if start_date and occurred_at and occurred_at < start_date:
                continue
            if end_date and occurred_at and occurred_at > end_date:
                continue
            line = " ".join(
                part
                for part in [
                    record.occurred_at.isoformat() if record.occurred_at else "",
                    record_level.upper(),
                    record.source,
                    record.event or "",
                    record.message,
                ]
                if part
            )
            if search_query and search_query not in line.lower():
                continue
            lines.append(line)
    elif source_id == "audit-db":
        query = select(AuditLog).order_by(AuditLog.occurred_at.desc().nullslast(), AuditLog.id.desc()).limit(limit * 5)
        result = await db.execute(query)
        records = result.scalars().all()
        for record in records:
            occurred_at = record.occurred_at.date().isoformat() if record.occurred_at else ""
            if start_date and occurred_at and occurred_at < start_date:
                continue
            if end_date and occurred_at and occurred_at > end_date:
                continue
            line = " ".join(
                part
                for part in [
                    record.occurred_at.isoformat() if record.occurred_at else "",
                    "INFO",
                    record.action,
                    record.target_type or "",
                    record.target_id or "",
                    record.result or "",
                ]
                if part
            )
            if search_query and search_query not in line.lower():
                continue
            lines.append(line)
    else:
        return None

    lines = list(reversed(lines[:limit]))
    return {
        "source_id": source_id,
        "name": "系统事件" if source_id == "system-db" else "审计事件",
        "kind": "database",
        "location": "table://system_logs" if source_id == "system-db" else "table://audit_logs",
        "description": "数据库持久化日志",
        "category": "database" if source_id == "system-db" else "audit",
        "status": "ok" if lines else "empty",
        "level": level,
        "selected_levels": sorted(selected_levels),
        "search_query": search or "",
        "available_levels": ["all", "error", "warning", "info", "debug"],
        "daily_markers": [],
        "line_limit": limit,
        "line_count": len(lines),
        "lines": lines,
    }


@router.get("/logs/{source_id}", response_model=SystemLogSnapshotResponse)
async def get_system_log_snapshot(
    source_id: str,
    limit: int = DEFAULT_LOG_LINE_LIMIT,
    level: str = "all",
    levels: str | None = Query(None, description="Comma-separated log levels"),
    start_date: str | None = Query(None, description="Filter logs from this date (YYYY-MM-DD)"),
    end_date: str | None = Query(None, description="Filter logs until this date (YYYY-MM-DD)"),
    search: str | None = Query(None, description="Case-insensitive substring search"),
    current_user: User = Depends(get_current_user),
    db: AsyncSession = Depends(get_db),
):
    ensure_super_admin(current_user)

    if limit < 1 or limit > MAX_LOG_LINE_LIMIT:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"limit must be between 1 and {MAX_LOG_LINE_LIMIT}",
        )
    if str(level).strip().lower() not in SUPPORTED_LOG_LEVELS and normalize_log_level(level) == "all" and str(level).strip().lower() not in {"", "all"}:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Unsupported log level")
    if levels:
        for raw_level in str(levels).split(","):
            normalized_level = str(raw_level).strip().lower()
            if not normalized_level:
                continue
            if normalized_level not in SUPPORTED_LOG_LEVELS and normalize_log_level(normalized_level) == "all":
                raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="Unsupported log level")
    normalized_start_date = validate_log_date(start_date, "start_date")
    normalized_end_date = validate_log_date(end_date, "end_date")
    if normalized_start_date and normalized_end_date and normalized_start_date > normalized_end_date:
        raise HTTPException(status_code=status.HTTP_400_BAD_REQUEST, detail="start_date must be earlier than or equal to end_date")

    snapshot = await read_database_log_snapshot(
        source_id,
        limit=limit,
        level=level,
        levels=levels,
        start_date=normalized_start_date,
        end_date=normalized_end_date,
        search=search,
        db=db,
    )
    if snapshot is None:
        snapshot = read_log_snapshot(
            source_id,
            limit,
            level=level,
            levels=levels,
            start_date=normalized_start_date,
            end_date=normalized_end_date,
            search=search,
        )
    if snapshot is None:
        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Log source not found")
    return snapshot


@router.post("/logs/earth-client", response_model=EarthClientLogEventResponse)
async def ingest_earth_client_log(
    payload: EarthClientLogEventCreate,
    request: Request,
):
    normalized_level = normalize_log_level(payload.level)
    append_buffer_log(
        "earth-client",
        level=normalized_level,
        message=payload.message,
        context={
            "category": payload.category or "",
            "url": payload.url or "",
            "module": payload.module or "",
            "detail": payload.detail or "",
        },
    )
    await record_system_log(
        source="earth-client",
        service="earth",
        module=payload.module or "earth-client",
        event="earth.client.runtime_log",
        level=normalized_level,
        message=payload.message,
        category=payload.category or "client-runtime",
        context={
            "url": payload.url or "",
            "detail": payload.detail or "",
            "module": payload.module or "",
            "client_ip": request.client.host if request.client else "",
        },
    )
    return {"accepted": True, "source_id": "earth-client", "level": normalized_level}