"""
RPA Engine — 소스 기반 Validation 학습 + 자동화 실행 + 크론 스케줄러 연동
"""
from __future__ import annotations

import ast
import json
import re
from datetime import datetime
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple

import httpx

BASE_DIR = Path(__file__).resolve().parent.parent   # itsm/
RULES_FILE = BASE_DIR / "rpa_rules.json"            # 학습 규칙 영속 파일

# 학습 대상 스키마: Create/Update/In/Request 접미사만 허용
_INPUT_SUFFIXES = ("Create", "Update", "In", "Request", "Input", "Patch")
# 제외 접미사
_SKIP_SUFFIXES  = ("Out", "Response", "Data", "Result", "Info", "Config",
                   "Filter", "Query", "Report", "Summary", "Status")


# ── Enum 매핑 ────────────────────────────────────────────────────────────────

ENUM_MAP: Dict[str, List[str]] = {
    "SRType":          ["DEPLOY", "RESTART", "LOG", "INQUIRY", "OTHER"],
    "SRStatus":        ["RECEIVED","PARSED","PENDING_APPROVAL","APPROVED",
                        "IN_PROGRESS","PENDING_PM_VALIDATION","COMPLETED",
                        "FAILED_ROLLBACK","REJECTED"],
    "Priority":        ["CRITICAL", "HIGH", "MEDIUM", "LOW"],
    "ApprovalResult":  ["PENDING", "APPROVED", "REJECTED"],
    "Severity":        ["CRITICAL", "HIGH", "MEDIUM", "LOW", "INFO"],
    "ChangeType":      ["STANDARD", "NORMAL", "EMERGENCY"],
    "ChangeStatus":    ["DRAFT", "SUBMITTED", "APPROVED", "REJECTED",
                        "IN_PROGRESS", "COMPLETED", "CANCELLED"],
    "ProblemStatus":   ["OPEN", "IN_ANALYSIS", "KNOWN_ERROR", "RESOLVED", "CLOSED"],
    "NetworkDeviceType": ["SWITCH", "ROUTER", "FIREWALL", "LOAD_BALANCER", "OTHER"],
    "DRStatus":        ["STANDBY", "ACTIVE", "TESTING", "FAILED"],
    "RiskLevel":       ["CRITICAL", "HIGH", "MEDIUM", "LOW"],
}


# ── Validation 학습 ─────────────────────────────────────────────────────────

class ValidationLearner:
    """
    models.py AST 파싱 + routers/ 스캔으로 Pydantic 입력 스키마 validation 규칙 추출.
    결과는 rpa_rules.json에 영속 저장.
    """

    # 수동 엔드포인트 → 스키마 매핑 (자동 스캔으로도 보완됨)
    _MANUAL_MAP: Dict[str, str] = {
        "POST /api/tasks":              "SRCreate",
        "PATCH /api/tasks/status":      "SRStatusUpdate",
        "POST /api/approvals":          "ApprovalCreate",
        "POST /api/institutions":       "InstitutionCreate",
        "PUT /api/institutions/{id}":   "InstitutionUpdate",
        "POST /api/servers":            "ServerCreate",
        "POST /api/incidents":          "IncidentCreate",
        "POST /api/change":             "RFCCreate",
        "POST /api/problems":           "ProblemCreate",
        "POST /api/catalog":            "ServiceCatalogCreate",
        "POST /api/kb":                 "KBDocumentCreate",
        "POST /api/shell-scripts":      "ShellScriptCreate",
        "POST /api/ssh/exec":           "SSHExecRequest",
    }

    def learn_from_source(self) -> Dict[str, Any]:
        """
        1) models.py AST 파싱 → 입력 스키마만 추출
        2) routers/ 스캔 → 엔드포인트-스키마 매핑 자동 보완
        3) 결과를 rpa_rules.json에 저장
        """
        # Step 1: 스키마 추출
        schemas = self._parse_models()

        # Step 2: 라우터 스캔으로 엔드포인트 매핑 자동 보완
        router_map = self._scan_routers()
        ep_map = {**self._invert_manual(), **router_map}  # router 스캔 우선

        # Step 3: 규칙 생성
        rules: List[Dict] = []
        for class_name, fields in schemas.items():
            endpoint = ep_map.get(class_name, self._infer_endpoint(class_name))
            for field in fields:
                field["endpoint"] = endpoint
                rules.append(field)

        # Step 4: 영속 저장
        payload = {
            "learned_at": datetime.now().isoformat(),
            "schema_count": len(schemas),
            "rule_count": len(rules),
            "rules": rules,
        }
        RULES_FILE.write_text(json.dumps(payload, ensure_ascii=False, indent=2), encoding="utf-8")

        return {
            "rules": rules,
            "schemas": list(schemas.keys()),
            "endpoint_count": len(set(r["endpoint"] for r in rules)),
        }

    def _parse_models(self) -> Dict[str, List[Dict]]:
        """models.py에서 입력 스키마 클래스만 파싱."""
        src = (BASE_DIR / "models.py").read_text(encoding="utf-8")
        tree = ast.parse(src)
        schemas: Dict[str, List[Dict]] = {}

        for node in ast.walk(tree):
            if not isinstance(node, ast.ClassDef):
                continue
            bases = [getattr(b, "id", "") for b in node.bases]
            if "BaseModel" not in bases:
                continue

            name = node.name
            # Out/Response 등 제외
            if any(name.endswith(s) for s in _SKIP_SUFFIXES):
                continue
            # Create/Update 등만 허용
            if not any(name.endswith(s) for s in _INPUT_SUFFIXES):
                continue

            fields = []
            for item in node.body:
                if not isinstance(item, ast.AnnAssign):
                    continue
                f = self._parse_field(item, name)
                if f:
                    fields.append(f)

            if fields:
                schemas[name] = fields

        return schemas

    def _parse_field(self, node: ast.AnnAssign, class_name: str) -> Optional[Dict]:
        if not isinstance(node.target, ast.Name):
            return None
        field_name = node.target.id
        if field_name.startswith("_"):
            return None

        type_str = ast.unparse(node.annotation) if hasattr(ast, "unparse") else ""
        is_required, field_type, allowed, constraints = self._analyse_type(type_str, node.value)

        return {
            "schema_class": class_name,
            "field_name": field_name,
            "field_type": field_type,
            "is_required": is_required,
            "allowed_values": allowed,
            "constraints": constraints,
            "learned_at": datetime.now().isoformat(),
            "endpoint": "",  # 후에 채워짐
        }

    def _analyse_type(
        self, type_str: str, default_node: Any
    ) -> Tuple[bool, str, List[str], Dict]:
        """타입 문자열 + AST 기본값 노드에서 (is_required, field_type, allowed, constraints) 반환."""
        # default가 있으면 required=False
        is_required = default_node is None
        # Optional[X] → required=False, 내부 타입 추출
        if "Optional" in type_str:
            is_required = False
            type_str = re.sub(r"Optional\[(.+)\]", r"\1", type_str)

        allowed: List[str] = []
        constraints: Dict = {}

        # Enum 매핑
        for enum_name, vals in ENUM_MAP.items():
            if enum_name in type_str:
                return is_required, "enum", vals, constraints

        # 기본 타입
        if "int" in type_str and "str" not in type_str:
            field_type = "int"
        elif "float" in type_str:
            field_type = "float"
        elif "bool" in type_str:
            field_type = "bool"
        elif "List" in type_str or "list" in type_str:
            field_type = "list"
        elif "datetime" in type_str.lower() or "date" in type_str.lower():
            field_type = "datetime"
        else:
            field_type = "str"

        return is_required, field_type, allowed, constraints

    def _scan_routers(self) -> Dict[str, str]:
        """
        routers/*.py에서 @router.post/put/patch 데코레이터와
        Body 파라미터 타입 힌트를 스캔해 {SchemaClass: "METHOD /path"} 반환.
        """
        schema_to_ep: Dict[str, str] = {}
        routers_dir = BASE_DIR / "routers"
        if not routers_dir.exists():
            return schema_to_ep

        for py_file in routers_dir.glob("*.py"):
            try:
                src = py_file.read_text(encoding="utf-8")
                tree = ast.parse(src)
            except Exception:
                continue

            # prefix 추출 (APIRouter(prefix="/api/xxx"))
            prefix = ""
            for node in ast.walk(tree):
                if isinstance(node, ast.Call):
                    func = getattr(node, "func", None)
                    if func and getattr(func, "id", "") == "APIRouter":
                        for kw in node.keywords:
                            if kw.arg == "prefix" and isinstance(kw.value, ast.Constant):
                                prefix = kw.value.value
                                break

            # 함수 → 데코레이터 + 파라미터 분석
            for node in ast.walk(tree):
                if not isinstance(node, ast.FunctionDef):
                    continue
                method, path = self._extract_route(node, prefix)
                if not method:
                    continue
                schema = self._extract_body_schema(node)
                if schema and schema not in schema_to_ep:
                    schema_to_ep[schema] = f"{method} {path}"

        return schema_to_ep

    def _extract_route(self, node: ast.FunctionDef, prefix: str) -> Tuple[str, str]:
        for dec in node.decorator_list:
            call = dec if isinstance(dec, ast.Call) else None
            if not call:
                continue
            attr = getattr(call.func, "attr", "")
            method = attr.upper() if attr in ("get","post","put","patch","delete") else ""
            if not method:
                continue
            path = ""
            if call.args and isinstance(call.args[0], ast.Constant):
                path = call.args[0].value
            elif call.keywords:
                for kw in call.keywords:
                    if kw.arg == "path" and isinstance(kw.value, ast.Constant):
                        path = kw.value.value
            return method, f"{prefix}{path}"
        return "", ""

    def _extract_body_schema(self, node: ast.FunctionDef) -> Optional[str]:
        """함수 파라미터에서 BaseModel 서브클래스 body 파라미터 타입 추출."""
        for arg in node.args.args:
            if arg.annotation is None:
                continue
            type_str = ast.unparse(arg.annotation) if hasattr(ast, "unparse") else ""
            # 단순 이름이면서 Create/Update/In 으로 끝나는 경우
            if any(type_str.endswith(s) for s in _INPUT_SUFFIXES):
                return type_str
        return None

    def _invert_manual(self) -> Dict[str, str]:
        return {v: k for k, v in self._MANUAL_MAP.items()}

    def _infer_endpoint(self, class_name: str) -> str:
        """스키마명에서 엔드포인트 자동 추론."""
        method = "POST"
        if class_name.endswith("Update") or class_name.endswith("Patch"):
            method = "PUT"
        base = re.sub(r"(Create|Update|In|Request|Input|Patch)$", "", class_name).lower()
        return f"{method} /api/{base}s"


# ── 규칙 로드 (영속 파일) ────────────────────────────────────────────────────

def load_rules() -> Dict[str, List[Dict]]:
    """rpa_rules.json에서 규칙 로드. 없으면 빈 dict."""
    if not RULES_FILE.exists():
        return {}
    try:
        data = json.loads(RULES_FILE.read_text(encoding="utf-8"))
        rules_by_ep: Dict[str, List[Dict]] = {}
        for r in data.get("rules", []):
            ep = r.get("endpoint", "")
            rules_by_ep.setdefault(ep, []).append(r)
        return rules_by_ep
    except Exception:
        return {}


def save_rules(rules_by_ep: Dict[str, List[Dict]]) -> None:
    """규칙 dict를 rpa_rules.json에 저장."""
    all_rules = [r for rules in rules_by_ep.values() for r in rules]
    payload = {
        "learned_at": datetime.now().isoformat(),
        "rule_count": len(all_rules),
        "rules": all_rules,
    }
    RULES_FILE.write_text(json.dumps(payload, ensure_ascii=False, indent=2), encoding="utf-8")


# ── Validation 검증기 ────────────────────────────────────────────────────────

class RPAValidator:
    """학습된 규칙으로 payload 검증."""

    def __init__(self, rules: List[Dict]):
        self.rules = {r["field_name"]: r for r in rules}

    def validate(self, payload: Dict[str, Any]) -> List[str]:
        errors: List[str] = []
        for field_name, rule in self.rules.items():
            val = payload.get(field_name)

            if rule["is_required"] and (val is None or val == ""):
                errors.append(f"[{field_name}] 필수 항목입니다.")
                continue

            if val is None:
                continue

            if rule["field_type"] == "enum" and rule["allowed_values"]:
                if val not in rule["allowed_values"]:
                    errors.append(
                        f"[{field_name}] 허용값: {rule['allowed_values']} 중 하나여야 합니다. (입력: {val!r})"
                    )
            elif rule["field_type"] == "int":
                try:
                    int(val)
                except (TypeError, ValueError):
                    errors.append(f"[{field_name}] 정수 타입이어야 합니다.")
            elif rule["field_type"] == "bool":
                if not isinstance(val, bool):
                    errors.append(f"[{field_name}] 불리언(true/false) 타입이어야 합니다.")

            c = rule.get("constraints", {})
            if c.get("max_length") and isinstance(val, str) and len(val) > c["max_length"]:
                errors.append(f"[{field_name}] 최대 {c['max_length']}자 초과.")
            if c.get("min_length") and isinstance(val, str) and len(val) < c["min_length"]:
                errors.append(f"[{field_name}] 최소 {c['min_length']}자 이상 필요.")

        return errors


# ── RPA 실행 엔진 ────────────────────────────────────────────────────────────

TASK_ENDPOINT_MAP: Dict[str, Tuple[str, str]] = {
    "SR_CREATE":        ("POST",  "/api/tasks"),
    "SR_STATUS_UPDATE": ("PATCH", "/api/tasks/{sr_id}/status"),
    "APPROVAL_PROCESS": ("POST",  "/api/approvals"),
    "INCIDENT_CREATE":  ("POST",  "/api/incidents"),
    "SHELL_EXEC":       ("POST",  "/api/ssh/exec"),
    "SR_BATCH_CREATE":  ("POST",  "/api/tasks/batch"),
}


class RPAExecutor:
    """학습 규칙 기반 ITSM API 자동 호출."""

    def __init__(self, base_url: str, token: str):
        self.base_url = base_url.rstrip("/")
        self.headers  = {"Authorization": f"Bearer {token}", "Content-Type": "application/json"}

    async def execute(
        self,
        task_type: str,
        payload: Dict[str, Any],
        dry_run: bool = False,
        retry: int = 3,
    ) -> Dict[str, Any]:
        if task_type not in TASK_ENDPOINT_MAP:
            return {"status": "FAILED", "error": f"알 수 없는 task_type: {task_type}"}

        method, path_tmpl = TASK_ENDPOINT_MAP[task_type]
        path = path_tmpl.format(**payload)
        result: Dict[str, Any] = {
            "task_type": task_type,
            "endpoint": f"{method} {path}",
            "dry_run": dry_run,
        }

        if dry_run:
            result.update(status="DRY_RUN_OK",
                          message="Validation 통과. dry_run=true이므로 실제 실행 생략.")
            return result

        url = f"{self.base_url}{path}"
        last_err: Optional[str] = None

        async with httpx.AsyncClient(timeout=30) as client:
            for attempt in range(1, retry + 1):
                try:
                    r = await client.request(method, url, json=payload, headers=self.headers)
                    if r.status_code < 300:
                        result.update(status="SUCCESS", response=r.json())
                        return result
                    elif r.status_code < 500:
                        result.update(status="FAILED", error=r.json())
                        return result
                    else:
                        last_err = f"HTTP {r.status_code}: {r.text[:200]}"
                except Exception as e:
                    last_err = str(e)

                if attempt < retry:
                    import asyncio
                    await asyncio.sleep(2 ** attempt)

        result.update(status="FAILED", error=f"{retry}회 재시도 후 실패: {last_err}")
        return result