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 app.core.config import ROOT_DIR
from app.core.security import get_current_user
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,
)

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


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.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()}


@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),
):
    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 = 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}