from datetime import datetime
from typing import Annotated, TypeVar

from core_domain import (
    ChatCompletionRequestContract,
    ChatCompletionResponseContract,
    ServiceHealth,
)
from fastapi import APIRouter, Depends, HTTPException
from sqlalchemy import text
from sqlalchemy.orm import Session

from app.application.services import ModelGatewayApplicationService
from app.bootstrap.settings import ModelGatewayServiceSettings
from app.db.session import get_db
from app.domain.repositories import ModelDefinitionRepository, ModelProviderDefinitionRepository
from app.infrastructure.provider import ModelProviderClient, ModelProviderClientError
from app.schemas.model import (
    ApiResponse,
    DeleteData,
    DiscoverModelsData,
    DiscoverModelsRequestDto,
    ModelCreateRequest,
    ModelCreateRequestDto,
    ModelDeleteRequestDto,
    ModelDto,
    ModelProviderCreateRequestDto,
    ModelProviderDeleteRequestDto,
    ModelProviderDto,
    ModelProviderTestData,
    ModelProviderTestRequestDto,
    ModelProviderUpdateRequestDto,
    ModelResponse,
    ModelStatusUpdateRequest,
    ModelTestData,
    ModelTestRequest,
    ModelTestRequestDto,
    ModelTestResponse,
    ModelUpdateRequest,
    ModelUpdateRequestDto,
    PageRequest,
    PageResult,
)

router = APIRouter()
DbSession = Annotated[Session, Depends(get_db)]
T = TypeVar("T")


def get_model_gateway_settings() -> ModelGatewayServiceSettings:
    return ModelGatewayServiceSettings()


def get_model_gateway_application_service(
    db: DbSession,
    settings: Annotated[
        ModelGatewayServiceSettings,
        Depends(get_model_gateway_settings),
    ]) -> ModelGatewayApplicationService:
    return ModelGatewayApplicationService(
        model_repository=ModelDefinitionRepository(db),
        provider_repository=ModelProviderDefinitionRepository(db),
        provider_client=ModelProviderClient(settings=settings),
        settings=settings)


ModelServiceDep = Annotated[
    ModelGatewayApplicationService,
    Depends(get_model_gateway_application_service),
]


def ok(data: T) -> ApiResponse[T]:
    return ApiResponse[T](
        data=data,
        requestId="",
        serverTime=datetime.utcnow())


@router.get("/health", response_model=ServiceHealth)
def health_check(
    db: DbSession,
    settings: Annotated[
        ModelGatewayServiceSettings,
        Depends(get_model_gateway_settings),
    ]) -> ServiceHealth:
    db.execute(text("SELECT 1"))
    provider_status = "configured" if settings.provider_base_url else "missing"
    return ServiceHealth(service="model-gateway-service", status="ok", database=provider_status)


@router.post("", response_model=ModelResponse)
def create_model(
    payload: ModelCreateRequest,
    service: ModelServiceDep,
) -> ModelResponse:
    try:
        entity = service.create_model(payload)
    except ValueError as exc:
        raise HTTPException(status_code=422, detail=str(exc)) from exc
    return ModelResponse.from_entity(entity)


@router.get("", response_model=list[ModelResponse])
def list_models(
    service: ModelServiceDep,
) -> list[ModelResponse]:
    return [ModelResponse.from_entity(item) for item in service.list_models()]


@router.patch("/{model_id}", response_model=ModelResponse)
def update_model(
    model_id: str,
    payload: ModelUpdateRequest,
    service: ModelServiceDep,
) -> ModelResponse:
    try:
        entity = service.update_model(model_id=model_id, payload=payload)
    except ValueError as exc:
        raise HTTPException(status_code=422, detail=str(exc)) from exc
    if entity is None:
        raise HTTPException(status_code=404, detail=f"model not found: {model_id}")
    return ModelResponse.from_entity(entity)


@router.patch("/{model_id}/status", response_model=ModelResponse)
def update_model_status(
    model_id: str,
    payload: ModelStatusUpdateRequest,
    service: ModelServiceDep,
) -> ModelResponse:
    entity = service.update_model_status(model_id=model_id, payload=payload)
    if entity is None:
        raise HTTPException(status_code=404, detail=f"model not found: {model_id}")
    return ModelResponse.from_entity(entity)


@router.delete("/{model_id}", status_code=204)
def delete_model(
    model_id: str,
    service: ModelServiceDep,
) -> None:
    if not service.delete_model(model_id):
        raise HTTPException(status_code=404, detail=f"model not found: {model_id}")


@router.post("/{model_id}/test", response_model=ModelTestResponse)
def test_model(
    model_id: str,
    payload: ModelTestRequest,
    service: ModelServiceDep,
) -> ModelTestResponse:
    try:
        result = service.test_model(model_id=model_id, payload=payload)
    except ModelProviderClientError as exc:
        raise HTTPException(status_code=502, detail=str(exc)) from exc
    if result is None:
        raise HTTPException(status_code=404, detail=f"model not found: {model_id}")
    return result


@router.post("/chat-completions", response_model=ChatCompletionResponseContract)
def create_chat_completion(
    payload: ChatCompletionRequestContract,
    service: ModelServiceDep) -> ChatCompletionResponseContract:
    try:
        return service.create_chat_completion(payload)
    except ModelProviderClientError as exc:
        raise HTTPException(status_code=502, detail=str(exc)) from exc


@router.post("/list", response_model=ApiResponse[PageResult[ModelDto]])
def list_models_contract(
    payload: PageRequest,
    service: ModelServiceDep) -> ApiResponse[PageResult[ModelDto]]:
    keyword = (payload.keyword or "").lower().strip()
    items = [
        item
        for item in service.list_models()
        if not keyword
        or keyword in item.name.lower()
        or keyword in item.model_name.lower()
        or keyword in item.provider_type.lower()
    ]
    page_items = items[payload.offset:payload.offset + payload.pageSize]
    return ok(
        PageResult[ModelDto].from_items(
            items=[ModelDto.from_entity(item) for item in page_items],
            total=len(items),
            page=payload.page,
            page_size=payload.pageSize))


@router.post("/create", response_model=ApiResponse[ModelDto])
def create_model_contract(
    payload: ModelCreateRequestDto,
    service: ModelServiceDep) -> ApiResponse[ModelDto]:
    try:
        entity = service.create_model_from_contract(payload)
    except ValueError as exc:
        raise HTTPException(status_code=422, detail=str(exc)) from exc
    return ok(ModelDto.from_entity(entity))


@router.post("/update", response_model=ApiResponse[ModelDto])
def update_model_contract(
    payload: ModelUpdateRequestDto,
    service: ModelServiceDep) -> ApiResponse[ModelDto]:
    try:
        entity = service.update_model_from_contract(payload)
    except ValueError as exc:
        raise HTTPException(status_code=422, detail=str(exc)) from exc
    if entity is None:
        raise HTTPException(status_code=404, detail=f"model not found: {payload.modelId}")
    return ok(ModelDto.from_entity(entity))


@router.post("/delete", response_model=ApiResponse[DeleteData])
def delete_model_contract(
    payload: ModelDeleteRequestDto,
    service: ModelServiceDep) -> ApiResponse[DeleteData]:
    deleted = service.delete_model_from_contract(payload)
    return ok(DeleteData(deleted=deleted, modelId=payload.modelId))


@router.post("/test", response_model=ApiResponse[ModelTestData])
def test_model_contract(
    payload: ModelTestRequestDto,
    service: ModelServiceDep) -> ApiResponse[ModelTestData]:
    try:
        result = service.test_model_from_contract(payload)
    except ModelProviderClientError as exc:
        raise HTTPException(status_code=502, detail=str(exc)) from exc
    if result is None:
        raise HTTPException(status_code=404, detail=f"model not found: {payload.modelId}")
    return ok(result)


@router.post("/providers/list", response_model=ApiResponse[PageResult[ModelProviderDto]])
def list_model_providers_contract(
    payload: PageRequest,
    service: ModelServiceDep) -> ApiResponse[PageResult[ModelProviderDto]]:
    keyword = (payload.keyword or "").lower().strip()
    items = [
        item
        for item in service.list_providers()
        if not keyword
        or keyword in item.name.lower()
        or keyword in item.provider_type.lower()
        or keyword in item.base_url.lower()
    ]
    page_items = items[payload.offset:payload.offset + payload.pageSize]
    return ok(
        PageResult[ModelProviderDto].from_items(
            items=[ModelProviderDto.from_entity(item) for item in page_items],
            total=len(items),
            page=payload.page,
            page_size=payload.pageSize))


@router.post("/providers/create", response_model=ApiResponse[ModelProviderDto])
def create_model_provider_contract(
    payload: ModelProviderCreateRequestDto,
    service: ModelServiceDep) -> ApiResponse[ModelProviderDto]:
    entity = service.create_provider(payload)
    return ok(ModelProviderDto.from_entity(entity))


@router.post("/providers/update", response_model=ApiResponse[ModelProviderDto])
def update_model_provider_contract(
    payload: ModelProviderUpdateRequestDto,
    service: ModelServiceDep) -> ApiResponse[ModelProviderDto]:
    entity = service.update_provider(payload)
    if entity is None:
        raise HTTPException(status_code=404, detail=f"provider not found: {payload.providerId}")
    return ok(ModelProviderDto.from_entity(entity))


@router.post("/providers/delete", response_model=ApiResponse[DeleteData])
def delete_model_provider_contract(
    payload: ModelProviderDeleteRequestDto,
    service: ModelServiceDep) -> ApiResponse[DeleteData]:
    deleted = service.delete_provider(payload)
    return ok(DeleteData(deleted=deleted, providerId=payload.providerId))


@router.post("/providers/test", response_model=ApiResponse[ModelProviderTestData])
def test_model_provider_contract(
    payload: ModelProviderTestRequestDto,
    service: ModelServiceDep) -> ApiResponse[ModelProviderTestData]:
    try:
        result = service.test_provider(payload)
    except ModelProviderClientError as exc:
        raise HTTPException(status_code=502, detail=str(exc)) from exc
    if result is None:
        raise HTTPException(status_code=404, detail=f"provider not found: {payload.providerId}")
    return ok(result)


@router.post("/providers/discover", response_model=ApiResponse[DiscoverModelsData])
def discover_models_contract(
    payload: DiscoverModelsRequestDto,
    service: ModelServiceDep) -> ApiResponse[DiscoverModelsData]:
    try:
        return ok(service.discover_models(payload))
    except ModelProviderClientError as exc:
        raise HTTPException(status_code=502, detail=str(exc)) from exc