"""
Admin API schemas — Pydantic v2.

All admin-facing request/response shapes live here to keep the admin router
clean and testable in isolation.
"""
import re
from datetime import datetime
from typing import Optional, Literal

from pydantic import BaseModel, ConfigDict, Field, field_validator

from app.schemas.auth import _validate_username, _validate_password_strength


# ---------------------------------------------------------------------------
# User list / detail
# ---------------------------------------------------------------------------

class UserListItem(BaseModel):
    id: int
    username: str
    email: Optional[str] = None
    first_name: Optional[str] = None
    last_name: Optional[str] = None
    role: str
    is_active: bool
    last_login_at: Optional[datetime] = None
    last_password_change_at: Optional[datetime] = None
    totp_enabled: bool
    mfa_enforce_pending: bool
    created_at: datetime
    active_sessions: int = 0

    model_config = ConfigDict(from_attributes=True)


class UserListResponse(BaseModel):
    users: list[UserListItem]
    total: int


class UserDetailResponse(UserListItem):
    preferred_name: Optional[str] = None
    must_change_password: bool = False
    locked_until: Optional[datetime] = None


# ---------------------------------------------------------------------------
# Mutating user requests
# ---------------------------------------------------------------------------

class CreateUserRequest(BaseModel):
    """Admin-created user — allows role selection (unlike public RegisterRequest)."""
    model_config = ConfigDict(extra="forbid")

    username: str
    password: str
    role: Literal["admin", "standard", "public_event_manager"] = "standard"
    email: Optional[str] = Field(None, max_length=254)
    first_name: Optional[str] = Field(None, max_length=100)
    last_name: Optional[str] = Field(None, max_length=100)
    preferred_name: Optional[str] = Field(None, max_length=100)

    @field_validator("username")
    @classmethod
    def validate_username(cls, v: str) -> str:
        return _validate_username(v)

    @field_validator("password")
    @classmethod
    def validate_password(cls, v: str) -> str:
        return _validate_password_strength(v)

    @field_validator("email")
    @classmethod
    def validate_email(cls, v: str | None) -> str | None:
        if v is None:
            return None
        v = v.strip().lower()
        if not v:
            return None
        # Basic format check: must have exactly one @, with non-empty local and domain parts
        if not re.match(r"^[^\s@]+@[^\s@]+\.[^\s@]+$", v):
            raise ValueError("Invalid email format")
        return v

    @field_validator("first_name", "last_name", "preferred_name")
    @classmethod
    def validate_name_fields(cls, v: str | None) -> str | None:
        if v is None:
            return None
        v = v.strip()
        if not v:
            return None
        # Reject ASCII control characters
        if re.search(r"[\x00-\x1f]", v):
            raise ValueError("Name must not contain control characters")
        return v


class UpdateUserRoleRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")
    role: Literal["admin", "standard", "public_event_manager"]


class ToggleActiveRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")
    is_active: bool


class ToggleMfaEnforceRequest(BaseModel):
    model_config = ConfigDict(extra="forbid")
    enforce: bool


# ---------------------------------------------------------------------------
# System config
# ---------------------------------------------------------------------------

class SystemConfigResponse(BaseModel):
    allow_registration: bool
    enforce_mfa_new_users: bool

    model_config = ConfigDict(from_attributes=True)


class SystemConfigUpdate(BaseModel):
    model_config = ConfigDict(extra="forbid")
    allow_registration: Optional[bool] = None
    enforce_mfa_new_users: Optional[bool] = None


# ---------------------------------------------------------------------------
# Admin dashboard
# ---------------------------------------------------------------------------

class RecentLoginItem(BaseModel):
    username: str
    last_login_at: Optional[datetime] = None

    model_config = ConfigDict(from_attributes=True)


class RecentAuditItem(BaseModel):
    action: str
    actor_username: Optional[str] = None
    target_username: Optional[str] = None
    created_at: datetime

    model_config = ConfigDict(from_attributes=True)


class AdminDashboardResponse(BaseModel):
    total_users: int
    active_users: int
    admin_count: int
    active_sessions: int
    mfa_adoption_rate: float
    recent_logins: list[RecentLoginItem]
    recent_audit_entries: list[RecentAuditItem]


# ---------------------------------------------------------------------------
# Password reset
# ---------------------------------------------------------------------------

class ResetPasswordResponse(BaseModel):
    message: str
    temporary_password: str


class DeleteUserResponse(BaseModel):
    message: str
    deleted_username: str


# ---------------------------------------------------------------------------
# Audit log
# ---------------------------------------------------------------------------

class AuditLogEntry(BaseModel):
    id: int
    actor_username: Optional[str] = None
    target_username: Optional[str] = None
    action: str
    detail: Optional[str] = None
    ip_address: Optional[str] = None
    created_at: datetime


class AuditLogResponse(BaseModel):
    entries: list[AuditLogEntry]
    total: int