/*
 * Copyright (c) 2025 SimcuTeam. All rights reserved.
 * 移植自 C# 项目 SimApi（E:\simcu\simapi-net），遵循 MIT 许可证。
 * 自定义 IRequestDelegateFactory：在结果派发时自动封装响应，
 * 对齐 C# SimApiResponseFilter（IResultFilter）的行为：
 *   - 返回 SimApiBaseResponse 或其子类 → 原样输出
 *   - 返回 null/void（Unit）→ SimApiBaseResponse()（{code:200, message:成功}）
 *   - 返回 String → SimApiResponse<String>（data 为字符串）
 *   - 返回其他对象 → SimApiResponse<Any>（data 为对象）
 *
 * 注册方式：必须在 soulsoft addControllers() 之前注册（tryAddSingleton 先到先得）。
 */

package simapi.extensions

import std.collection.*
import std.reflect.*
import soulsoft_web_http.*
import soulsoft_web_mvc.core.*
import soulsoft_web_mvc.routing.*
import soulsoft_web_mvc.controllers.*
import soulsoft_web_mvc.modelBindings.*
import soulsoft_web_mvc.abstractions.*
import soulsoft_extensions_options.*
import soulsoft_extensions_injection.*
import simapi.attributes.{SimApiAuth, OriginResponse}
import simapi.communications.*
import simapi.configurations.*
import simapi.controllers.*
import simapi.helpers.{SimApiError}
import simapi.interfaces.*

/**
 * 自定义请求委托工厂：接管 soulsoft 的 ControllerRequestDelegateFactory，
 * 在结果派发时自动封装响应（对齐 C# SimApiResponseFilter）。
 */
public class SimApiRequestDelegateFactory <: IRequestDelegateFactory {
    private let _mvcOptions: MvcOptions
    private let _modelBinder: IActionModelBinder

    public init(mvcOptions: IOptions<MvcOptions>, modelBinder: IActionModelBinder, services: IServiceProvider) {
        _mvcOptions = mvcOptions.value
        _modelBinder = modelBinder
    }

    public func createRequestDelegate(actionDescriptor: ControllerActionDescriptor): RequestDelegate {
        return {
            context => SimApiActionInvoker(context, _modelBinder, actionDescriptor, _mvcOptions).apply()
        }
    }
}

/**
 * 单次请求的动作执行器（复制 soulsoft ControllerActionInvoker，
 * dispatchResult 改为自动封装响应）。
 */
struct SimApiActionInvoker {
    SimApiActionInvoker(let context: HttpContext, let modelBinder: IActionModelBinder,
        let actionDescriptor: ControllerActionDescriptor, let mvcOptions: MvcOptions) {
    }

    public func apply(): Unit {
        let controller = createControllerInstance()
        checkSimApiAuth()
        let modelBindingContext = ActionBindingContext(context, actionDescriptor.actionFunction.parameters)
        let boundParameters = modelBinder.bind(modelBindingContext)
        if (!modelBindingContext.modelState.isValid) {
            handleInvalidModelState(modelBindingContext)
        } else {
            let actionResult = actionDescriptor.actionFunction.apply(controller, boundParameters)
            dispatchResult(actionResult)
        }
    }

    /// 检查 @SimApiAuth 注解并执行鉴权（对齐 C# SimApiAuthAttribute.OnActionExecuting）：
    /// 未登录 401 → 类型权限 403 → 遍历执行 ISimApiAuthChecker
    private func checkSimApiAuth() {
        var auth: ?SimApiAuth = None
        for (item in actionDescriptor.endpointMetadata) {
            if (let a: SimApiAuth <- item) {
                auth = Some(a)
                break
            }
        }
        if (let Some(auth) <- auth) {
            // 1. 未登录 → 401
            var loginItem: SimApiLoginItem = SimApiLoginItem("")
            match (context.items.get("LoginInfo")) {
                case Some(v) =>
                    if (let l: SimApiLoginItem <- v) {
                        loginItem = l
                    } else {
                        SimApiError.error(code: 401, message: "需要登录")
                    }
                case None =>
                    SimApiError.error(code: 401, message: "需要登录")
            }

            // 2. 类型权限校验 → 403（对齐 C# Types.Intersect(loginInfo.Type).Any()，支持逗号分隔多类型）
            if (!auth.`type`.isEmpty()) {
                let requiredTypes = auth.`type`.split(",")
                var matched = false
                for (t in requiredTypes) {
                    if (loginItem._types.contains(t)) {
                        matched = true
                        break
                    }
                }
                if (!matched) {
                    SimApiError.error(code: 403, message: "无权访问")
                }
            }

            // 3. 遍历执行 ISimApiAuthChecker（从 DI 按注册类型解析）
            let token = match (context.items.get("LoginToken")) {
                case Some(v) => if (let s: String <- v) { s } else { "" }
                case None => ""
            }
            let options = context.services.getOrThrow<SimApiOptions>()
            for (checkerType in options.authCheckers) {
                let instance = context.services.getOrThrow(checkerType)
                if (let checker: ISimApiAuthChecker <- instance) {
                    checker.run(loginItem, token)
                }
            }
        }
    }

    /// 模型绑定失败时写入 ProblemDetails 响应
    private func handleInvalidModelState(modelBindingContext: ActionBindingContext) {
        let options = context.services.getOrThrow<IOptions<ApiBehaviorOptions>>()
        if (let Some(factory) <- options.value.invalidModelStateResponseFactory) {
            let actionContext = ActionContext(context, modelBindingContext.modelState)
            factory(actionContext).invoke(context)
        } else {
            let details = createValidationProblemDetails(modelBindingContext)
            if (let Some(status) <- details.status) {
                context.response.statusCode = UInt16(status)
            }
            context.response.writeAsJson(details)
        }
    }

    /// 结果派发 + 自动封装（对齐 C# SimApiResponseFilter）
    private func dispatchResult(actionResult: Any) {
        // @OriginResponse：跳过统一封装，原样输出（对齐 C# OnResultExecuting 遇注解直接 return）
        var originResponse = false
        for (item in actionDescriptor.endpointMetadata) {
            if (item is OriginResponse) {
                originResponse = true
                break
            }
        }
        if (originResponse) {
            if (let s: String <- actionResult) {
                // String 原样输出文本（对齐 C# string 返回直接写入）
                context.response.contentType = "application/json; charset=utf-8"
                context.response.write(s)
            } else {
                ObjectResult<Any>(actionResult).invoke(context)
            }
            return
        }
        // 统一封装（IActionResult/SimApiBaseResponse/String/Unit/其他对象）
        SimApiResultWriter.write(context, actionResult)
    }

    /// 根据 ModelState 错误构建 ValidationProblemDetails
    private func createValidationProblemDetails(modelBindingContext: ActionBindingContext) {
        let details = ValidationProblemDetails()
        if (hasUnsupportedContentTypeError(modelBindingContext.modelState)) {
            details.`type` = "https://tools.ietf.org/html/rfc9110#section-15.5.16"
            details.title = "Unsupported Media Type"
            details.status = 415
        } else {
            details.`type` = "https://tools.ietf.org/html/rfc9110#section-15.5.1"
            details.title = "One or more validation errors occurred."
            details.status = 400
            for ((name, entry) in modelBindingContext.modelState) {
                details.errors.add(name, entry.errors |> map {f => f.description} |> collectArray)
            }
        }
        return details
    }

    /// 检查 ModelState 中是否含有 UnsupportedContentTypeException 错误
    private func hasUnsupportedContentTypeError(modelState: ModelStateDictionary) {
        for ((_, entry) in modelState) {
            for (error in entry.errors) {
                if (error.exception.flatMap {f => f as UnsupportedContentTypeException}.isSome()) {
                    return true
                }
            }
        }
        return false
    }

    /// 通过 DI 容器实例化控制器，并注入当前 HttpContext
    private func createControllerInstance(): Object {
        let instance = ActivatorUtilities.createInstance(context.services, actionDescriptor.controllerType)
        if (let controller: SimApiBaseController <- instance) {
            controller.bindRequestContext(context)
        }
        return instance
    }
}