from __future__ import annotations

import ipaddress
import re

from pydantic import BaseModel, ConfigDict, Field, field_validator, model_validator

HOSTNAME_RE = re.compile(
    r"^(?=.{1,253}\.?$)(?:[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?\.)+"
    r"[a-zA-Z]{2,63}\.?$"
)
AWS_REGION_RE = re.compile(r"^[a-z]{2}(?:-gov)?-[a-z0-9-]+-\d+$")


def _normalize_hostname(value: str) -> str:
    normalized = value.strip().rstrip(".").lower()
    if not HOSTNAME_RE.fullmatch(normalized):
        raise ValueError("请输入完整域名")
    return normalized


class ManagedInstanceBase(BaseModel):
    display_name: str = Field(min_length=1, max_length=80)
    aws_region: str = Field(min_length=3, max_length=32)
    lightsail_instance_name: str = Field(min_length=1, max_length=255)
    cloudflare_zone_name: str = Field(min_length=3, max_length=253)
    cloudflare_zone_id: str = Field(default="", max_length=64)
    cloudflare_record_name: str = Field(min_length=3, max_length=253)
    socks_port: int = Field(default=1080, ge=1, le=65535)
    proxy_health_check: bool = True
    health_timeout_seconds: int = Field(default=120, ge=10, le=600)
    release_grace_seconds: int = Field(default=75, ge=60, le=600)
    enabled: bool = True

    @field_validator(
        "display_name",
        "aws_region",
        "lightsail_instance_name",
        "cloudflare_zone_id",
        mode="before",
    )
    @classmethod
    def strip_text(cls, value: object) -> object:
        return value.strip() if isinstance(value, str) else value

    @field_validator("aws_region")
    @classmethod
    def validate_region(cls, value: str) -> str:
        normalized = value.lower()
        if not AWS_REGION_RE.fullmatch(normalized):
            raise ValueError("请输入有效的 AWS 区域")
        return normalized

    @field_validator("cloudflare_zone_name", "cloudflare_record_name")
    @classmethod
    def validate_hostname(cls, value: str) -> str:
        return _normalize_hostname(value)

    @model_validator(mode="after")
    def validate_dns_relationship(self) -> ManagedInstanceBase:
        if (
            self.cloudflare_record_name != self.cloudflare_zone_name
            and not self.cloudflare_record_name.endswith(f".{self.cloudflare_zone_name}")
        ):
            raise ValueError("DNS 记录必须属于 Cloudflare Zone")
        return self


class ManagedInstanceCreate(ManagedInstanceBase):
    id: str | None = Field(default=None, min_length=1, max_length=128)
    group_id: str | None = Field(default=None, min_length=1, max_length=128)

    @field_validator("group_id", mode="before")
    @classmethod
    def normalize_group_id(cls, value: object) -> object:
        if isinstance(value, str):
            return value.strip() or None
        return value


class ManagedInstanceUpdate(BaseModel):
    config_version: int = Field(ge=1)
    group_id: str | None = Field(default=None, min_length=1, max_length=128)
    display_name: str | None = Field(default=None, min_length=1, max_length=80)
    aws_region: str | None = Field(default=None, min_length=3, max_length=32)
    lightsail_instance_name: str | None = Field(default=None, min_length=1, max_length=255)
    cloudflare_zone_name: str | None = Field(default=None, min_length=3, max_length=253)
    cloudflare_zone_id: str | None = Field(default=None, max_length=64)
    cloudflare_record_name: str | None = Field(default=None, min_length=3, max_length=253)
    socks_port: int | None = Field(default=None, ge=1, le=65535)
    proxy_health_check: bool | None = None
    health_timeout_seconds: int | None = Field(default=None, ge=10, le=600)
    release_grace_seconds: int | None = Field(default=None, ge=60, le=600)
    enabled: bool | None = None

    @field_validator("group_id", mode="before")
    @classmethod
    def normalize_group_id(cls, value: object) -> object:
        if isinstance(value, str):
            return value.strip() or None
        return value

    @field_validator(
        "display_name",
        "aws_region",
        "lightsail_instance_name",
        "cloudflare_zone_id",
        mode="before",
    )
    @classmethod
    def strip_text(cls, value: object) -> object:
        return value.strip() if isinstance(value, str) else value

    @field_validator("aws_region")
    @classmethod
    def validate_region(cls, value: str | None) -> str | None:
        if value is None:
            return None
        normalized = value.lower()
        if not AWS_REGION_RE.fullmatch(normalized):
            raise ValueError("请输入有效的 AWS 区域")
        return normalized

    @field_validator("cloudflare_zone_name", "cloudflare_record_name")
    @classmethod
    def validate_hostname(cls, value: str | None) -> str | None:
        return _normalize_hostname(value) if value is not None else None

    @model_validator(mode="after")
    def validate_dns_relationship(self) -> ManagedInstanceUpdate:
        zone = self.cloudflare_zone_name
        record = self.cloudflare_record_name
        if zone and record and record != zone and not record.endswith(f".{zone}"):
            raise ValueError("DNS 记录必须属于 Cloudflare Zone")
        if not self.model_fields_set - {"config_version"}:
            raise ValueError("请至少修改一项实例配置")
        return self


class ManagedInstanceStatusUpdate(BaseModel):
    last_known_ip: str | None = None
    last_checked_at: str | None = None

    @field_validator("last_known_ip")
    @classmethod
    def validate_ipv4(cls, value: str | None) -> str | None:
        if value is None:
            return None
        try:
            address = ipaddress.ip_address(value.strip())
        except ValueError as exc:
            raise ValueError("请输入有效的 IPv4 地址") from exc
        if address.version != 4:
            raise ValueError("只支持 IPv4 地址")
        return str(address)


class ManagedInstanceView(ManagedInstanceBase):
    model_config = ConfigDict(from_attributes=True)

    id: str
    config_version: int
    last_known_ip: str | None
    last_checked_at: str | None
    created_at: str
    updated_at: str
    archived_at: str | None


class InstanceGroupCreate(BaseModel):
    id: str | None = Field(default=None, min_length=1, max_length=128)
    name: str = Field(min_length=1, max_length=80)
    enabled: bool = False
    interval_minutes: int = Field(default=60, ge=5, le=10080)
    member_ids: list[str] = Field(default_factory=list, max_length=1000)

    @field_validator("name", mode="before")
    @classmethod
    def strip_name(cls, value: object) -> object:
        return value.strip() if isinstance(value, str) else value

    @field_validator("member_ids")
    @classmethod
    def unique_members(cls, value: list[str]) -> list[str]:
        normalized = [item.strip() for item in value]
        if any(not item for item in normalized):
            raise ValueError("实例 ID 不能为空")
        if len(set(normalized)) != len(normalized):
            raise ValueError("实例组中不能包含重复实例")
        return normalized

    @model_validator(mode="after")
    def validate_enabled_members(self) -> InstanceGroupCreate:
        if self.enabled and not self.member_ids:
            raise ValueError("启用的实例组至少需要一个实例")
        return self


class InstanceGroupUpdate(BaseModel):
    config_version: int = Field(ge=1)
    name: str | None = Field(default=None, min_length=1, max_length=80)
    enabled: bool | None = None
    interval_minutes: int | None = Field(default=None, ge=5, le=10080)
    member_ids: list[str] | None = Field(default=None, max_length=1000)

    @field_validator("name", mode="before")
    @classmethod
    def strip_name(cls, value: object) -> object:
        return value.strip() if isinstance(value, str) else value

    @field_validator("member_ids")
    @classmethod
    def unique_members(cls, value: list[str] | None) -> list[str] | None:
        if value is None:
            return None
        normalized = [item.strip() for item in value]
        if any(not item for item in normalized):
            raise ValueError("实例 ID 不能为空")
        if len(set(normalized)) != len(normalized):
            raise ValueError("实例组中不能包含重复实例")
        return normalized

    @model_validator(mode="after")
    def require_change(self) -> InstanceGroupUpdate:
        if not self.model_fields_set - {"config_version"}:
            raise ValueError("请至少修改一项实例组配置")
        return self


class InstanceGroupMembersUpdate(BaseModel):
    member_ids: list[str] = Field(max_length=1000)

    @field_validator("member_ids")
    @classmethod
    def unique_members(cls, value: list[str]) -> list[str]:
        normalized = [item.strip() for item in value]
        if any(not item for item in normalized):
            raise ValueError("实例 ID 不能为空")
        if len(set(normalized)) != len(normalized):
            raise ValueError("实例组中不能包含重复实例")
        return normalized


class InstanceGroupView(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: str
    name: str
    enabled: bool
    interval_minutes: int
    next_run_at: str | None
    last_run_at: str | None
    config_version: int
    member_ids: list[str]
    created_at: str
    updated_at: str
    archived_at: str | None


class FleetRunView(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: str
    target_type: str
    target_id: str
    target_name: str
    trigger: str
    status: str
    current_item_id: str | None
    error_code: str | None
    error_message: str | None
    total_items: int
    succeeded_items: int
    started_at: str
    updated_at: str
    finished_at: str | None


class FleetRunItemView(BaseModel):
    model_config = ConfigDict(from_attributes=True)

    id: str
    run_id: str
    instance_id: str
    position: int
    status: str
    stage: str
    stage_started_at: str
    attempt_count: int
    config_version: int
    instance_display_name: str
    aws_region: str
    lightsail_instance_name: str
    cloudflare_zone_name: str
    cloudflare_zone_id: str
    cloudflare_record_name: str
    socks_port: int
    proxy_health_check: bool
    health_timeout_seconds: int
    release_grace_seconds: int
    old_static_ip_name: str | None
    old_ip: str | None
    new_static_ip_name: str | None
    new_ip: str | None
    dns_ip_before: str | None
    dns_ip_after: str | None
    grace_until: str | None
    aws_operation_id: str | None
    error_code: str | None
    error_message: str | None
    rollback_from_stage: str | None
    rollback_reason_code: str | None
    rollback_reason_message: str | None
    started_at: str
    updated_at: str
    finished_at: str | None


# Short aliases keep service imports readable without changing generated schema names.
InstanceCreate = ManagedInstanceCreate
InstanceUpdate = ManagedInstanceUpdate
InstanceStatusUpdate = ManagedInstanceStatusUpdate
InstanceView = ManagedInstanceView
GroupCreate = InstanceGroupCreate
GroupUpdate = InstanceGroupUpdate
GroupMembersUpdate = InstanceGroupMembersUpdate
GroupView = InstanceGroupView