import {RpcTransport, RpcOptions, MethodInfo} from '@protobuf-ts/runtime-rpc'
import axios, {AxiosRequestConfig, AxiosResponse} from 'axios'
import {JsonObject} from '@protobuf-ts/runtime/build/types/json-typings'
import {ElMessage} from 'element-plus'

/**
 * Represents a promise that resolves to an Axios response containing the output-resp object.
 *
 * @template I - The type of the input-param object.
 * @template O - The type of the output-resp object.
 */
export type GrtpPromise<I, O> = Promise<AxiosResponse<O, AxiosRequestConfig<I>>>

/**
 * Performs a gRPC call over HTTP using the specified transport mechanism, method information, and provided options.
 * Returns a promise that resolves to the Axios response containing the output-resp object.
 *
 * @template I - The type of the input-param object.
 * @template O - The type of the output-resp object.
 * @param callType - The type of the gRPC call (e.g., unary, server streaming).
 * @param transport - The transport mechanism for the gRPC call.
 * @param method - The method information for the gRPC call.
 * @param options - The options for the gRPC call, including the base URL and metadata.
 * @param input - The input-param object containing the request data.
 * @returns A promise that resolves to the Axios response containing the output-resp object.
 * @throws Will throw an error if the HTTP method is not defined or if a required parameter is missing.
 */
export function executeGrtp<I extends object, O extends object>(
    callType: string,
    transport: RpcTransport,
    method: MethodInfo<I, O>,
    options: RpcOptions,
    input: I,
): GrtpPromise<I, O> {
    console.debug('GRPC:', 'C:', callType, 'T:', transport, 'M:', method, 'O:', options, 'I:', input)

    const baseUrl = options['baseUrl'] as string; //目前是这样的
    const apiHttp = method.options['google.api.http'] as JsonObject //目前是这样的

    const reqMethods = ['get', 'post', 'put', 'delete']
    const httpMethod = Object.keys(apiHttp).find((key) => reqMethods.includes(key)) as string
    if (!httpMethod) {
        const reason = Object.keys(apiHttp).length === 0
            ? 'Request error - No HTTP method defined in GRPC'
            : 'Request error - Non GET/POST/PUT/DELETE HTTP method defined in GRPC'
        ElMessage.error(reason)
        throw new Error(reason)
    }
    let uriPath = apiHttp[httpMethod] as string

    let queryParams: I | undefined = undefined
    let requestBody: I | undefined = undefined
    if (apiHttp.body === '*') { //假如没有 body 属性，结果将是 undefined，这样它依然是不等于*的，而不会导致运行时报错
        requestBody = input
    } else {
        if (uriPath.includes('{') && uriPath.includes('}')) {
            uriPath = rewritePathParam(uriPath, input)
        } else {
            queryParams = input
        }
    }
    const fullUrl = urlCombine(baseUrl, uriPath)
    console.debug(`Http Method: ${httpMethod}, Full URL: ${fullUrl} (Base URL: ${baseUrl}, Uri Path: ${uriPath})`)

    const axiosConfig: AxiosRequestConfig = {
        method: httpMethod,
        url: fullUrl,
        params: queryParams, //当遇到get请求时-这样直接写上就行-也不用转成查询参数放在后面
        data: requestBody,
        headers: options.meta, //这里好像两个数据都允许为空因为没有问题
    }

    return axios.request<O, AxiosResponse<O, AxiosRequestConfig>>(axiosConfig)
}

/**
 * Rewrites the URI path by replacing path parameters with corresponding values from the input-param object.
 * If a parameter is not found in the input-param object, it attempts to convert the parameter name from snake_case to camelCase.
 *
 * @template T - The type of the input-param object.
 * @param uriPath - The URI path containing parameters in the format `{param}`.
 * @param input - The input-param object containing values for the parameters.
 * @returns The URI path with parameters replaced by their corresponding values from the input-param object.
 * @throws Will throw an error if a parameter is missing in the input-param object.
 */
function rewritePathParam<T extends object>(uriPath: string, input: T): string {
    const params = uriPath.match(/{(\w+)}/g)
    if (params) {
        params.forEach((param) => {
            const paramName = param.slice(1, -1)
            let value = input[paramName]

            if (value === undefined) {
                // 尝试将蛇形命名法转换为小驼峰命名法(example_param_name->exampleParamName)
                const newParamName = toCamelCase(paramName)
                value = input[newParamName]
            }

            if (value === undefined) {
                const reason = `MISSING PARAMETER: ${paramName}`
                ElMessage.error(reason)
                throw new Error(reason)
            }

            uriPath = uriPath.replace(param, encodeURIComponent(value))
        })
    }
    return uriPath
}

/**
 * Combines a base URL and a URI path into a single URL.
 * Ensures that there is exactly one slash between the base URL and the URI path.
 *
 * @param urb - The base URL.
 * @param uri - The URI path to be appended to the base URL.
 * @returns The combined URL.
 */
export function urlCombine(urb: string, uri: string): string {
    let res: string
    if (urb.endsWith('/') || uri.startsWith('/')) {
        res = urb + uri
    } else {
        res = urb + '/' + uri
    }
    return res
}

/**
 * Converts a snake_case string to camelCase.
 * For example, `example_param_name` will be converted to `exampleParamName`.
 *
 * @param paramName - The snake_case string to be converted.
 * @returns The converted camelCase string.
 */
function toCamelCase(paramName: string): string {
    return paramName.replace(/_([a-z])/g, (g) => g[1].toUpperCase())
}