"""Public task backend configuration; runtime credentials stay server-side."""

from typing import Any, Literal
from urllib.parse import urlsplit

from pydantic import ConfigDict, Field, field_validator, model_validator
from schemas import CamelModel, ToolBinding


class TaskBackendConfig(CamelModel):
    model_config = ConfigDict(extra="forbid")

    instructions: str = Field(default="", max_length=16000)
    timeout_seconds: int = Field(default=600, ge=30, le=7200)
    max_concurrency: Literal[1] = 1


class TaskSkill(CamelModel):
    model_config = ConfigDict(extra="forbid")
    name: str = Field(min_length=1, max_length=128)
    content: str = Field(min_length=1, max_length=16000)

    @field_validator("name", "content")
    @classmethod
    def require_nonempty(cls, value: str) -> str:
        if not value.strip():
            raise ValueError("技能名称和正文不能为空")
        return value.strip()


class ReasonerBackendConfig(TaskBackendConfig):
    model_resource_id: str = Field(min_length=1, max_length=40)
    reasoning_effort: Literal["provider_default", "low", "medium", "high"] = "provider_default"
    tool_bindings: list[ToolBinding] = Field(default_factory=list, max_length=50)
    skills: list[TaskSkill] = Field(default_factory=list, max_length=20)

    @model_validator(mode="after")
    def unique_bindings_and_skills(self):
        ids = [binding.tool_id for binding in self.tool_bindings]
        if len(ids) != len(set(ids)):
            raise ValueError("Reasoner 工具绑定不能重复")
        names = [skill.name for skill in self.skills]
        if len(names) != len(set(names)):
            raise ValueError("技能名称不能重复")
        return self


class OpenCodeBackendConfig(TaskBackendConfig):
    url: str = Field(min_length=1, max_length=2048)
    directory: str = Field(min_length=1, max_length=2048)
    username: str = Field(default="opencode", max_length=128)
    agent: str = Field(default="", max_length=128)
    model_provider_id: str = Field(default="", max_length=128)
    model_id: str = Field(default="", max_length=256)
    skills_note: str = Field(default="", max_length=4000)

    @field_validator("url")
    @classmethod
    def validate_url(cls, value: str) -> str:
        parsed = urlsplit(value)
        if parsed.scheme not in {"http", "https"} or not parsed.hostname or parsed.username or parsed.password or parsed.query or parsed.fragment:
            raise ValueError("任务服务须使用不含凭证、查询参数的 HTTP(S) 地址")
        return value.rstrip("/")

    @field_validator("directory")
    @classmethod
    def require_directory(cls, value: str) -> str:
        if not value.strip():
            raise ValueError("必须填写远端工作目录")
        return value.strip()

    @model_validator(mode="after")
    def require_model_pair(self):
        if bool(self.model_provider_id) != bool(self.model_id):
            raise ValueError("远端模型的 provider ID 和 model ID 必须同时填写")
        return self


class TaskBackendUpsert(CamelModel):
    name: str = Field(min_length=1, max_length=128)
    type: Literal["reasoner", "opencode"]
    description: str = Field(default="", max_length=2048)
    config: ReasonerBackendConfig | OpenCodeBackendConfig
    secrets: dict[str, Any] = Field(default_factory=dict)
    enabled: bool = True

    @model_validator(mode="before")
    @classmethod
    def select_config(cls, value):
        if isinstance(value, dict) and value.get("type") in {"reasoner", "opencode"}:
            value = dict(value)
            config_class = ReasonerBackendConfig if value["type"] == "reasoner" else OpenCodeBackendConfig
            raw = value.get("config") or {}
            if isinstance(raw, CamelModel):
                raw = raw.model_dump()
            value["config"] = config_class.model_validate(raw)
        return value

    @field_validator("name")
    @classmethod
    def require_name(cls, value: str) -> str:
        if not value.strip():
            raise ValueError("后端名称不能为空")
        return value.strip()


class TaskBackendOut(TaskBackendUpsert):
    id: str
    updated_at: str | None = None