package httpapi

import (
	"encoding/json"
	"net/http"
	"strings"
	"time"
	"unicode"
)

const (
	reasonMalformedRequest = "MALFORMED_REQUEST"
	reasonMethodNotAllowed = "METHOD_NOT_ALLOWED"
	reasonForbidden        = "FORBIDDEN"
	reasonInternal         = "INTERNAL"
)

type apiError struct {
	Code       int            `json:"code"`
	Reason     string         `json:"reason"`
	Message    string         `json:"message"`
	Details    map[string]any `json:"details,omitempty"`
	RequestID  string         `json:"request_id,omitempty"`
	ServerTime string         `json:"server_time"`
}

var apiErrorMessages = map[string]string{
	"MALFORMED_REQUEST":              "请求参数格式错误",
	"METHOD_NOT_ALLOWED":             "当前请求方式不支持",
	"AUTH_REQUIRED":                  "登录已失效，请重新登录",
	"FORBIDDEN":                      "当前账户无权执行此操作",
	"INTERNAL":                       "服务异常，请稍后重试",
	"SERVICE_UNAVAILABLE":            "服务暂不可用，请稍后重试",
	"USERNAME_INVALID_FORMAT":        "用户名格式不正确",
	"PHONE_INVALID_FORMAT":           "手机号码格式不正确",
	"PASSWORD_INVALID_FORMAT":        "密码格式不正确",
	"REFERRAL_CODE_INVALID":          "邀请码无效，请检查后重新输入",
	"PRIVACY_POLICY_NOT_ACCEPTED":    "请先阅读并同意用户协议和隐私政策",
	"ACCOUNT_ALREADY_REGISTERED":     "该账户或手机号已经注册",
	"INVALID_CREDENTIALS":            "手机号或密码错误",
	"RATE_LIMITED":                   "操作过于频繁，请稍后再试",
	"AVATAR_ATTACHMENT_INVALID":      "头像图片无效，请重新上传",
	"CURRENT_PASSWORD_INVALID":       "当前登录密码不正确",
	"LOGIN_PASSWORD_INVALID":         "登录密码不正确",
	"NEW_PASSWORD_INVALID":           "新密码格式不正确",
	"OLD_TRADE_PASSWORD_REQUIRED":    "请输入原支付密码",
	"OLD_TRADE_PASSWORD_INVALID":     "原支付密码不正确",
	"TRADE_PASSWORD_INVALID":         "支付密码不正确",
	"TRADE_PASSWORD_NOT_SET":         "请先设置支付密码",
	"ACCOUNT_NOT_FOUND":              "账户不存在",
	"ACCOUNT_CHANGED":                "账户信息已发生变化，请重试",
	"CATEGORY_ID_INVALID":            "商品分类参数不正确",
	"PRODUCT_ID_INVALID":             "商品参数不正确",
	"PRODUCT_NOT_FOUND":              "商品不存在或已下架",
	"PAGE_INVALID":                   "页码参数不正确",
	"PAGE_SIZE_INVALID":              "每页数量参数不正确",
	"IMAGE_INVALID":                  "图片格式或大小不符合要求",
	"HALL_ID_INVALID":                "任务大厅参数不正确",
	"ORDER_ID_INVALID":               "订单参数不正确",
	"ORDER_STATUS_INVALID":           "订单状态参数不正确",
	"EVIDENCE_INVALID":               "任务凭证不符合要求",
	"TASK_DISABLED":                  "领取功能暂未开放",
	"OUTSIDE_BUSINESS_HOURS":         "当前不在营业时间内",
	"INSUFFICIENT_BALANCE":           "可用余额不足",
	"DAILY_LIMIT_REACHED":            "今日领取次数已用完",
	"LEVEL_NOT_ELIGIBLE":             "当前会员等级不满足领取条件",
	"ACCOUNT_RESTRICTED":             "账户状态受限，请联系客服",
	"PENDING_ORDER_EXISTS":           "存在未完成的任务，请先处理",
	"NO_TASK_AVAILABLE":              "当前暂无可领取任务",
	"ORDER_NOT_FOUND":                "任务订单不存在",
	"ORDER_STATE_INVALID":            "当前任务状态不允许此操作",
	"ORDER_EXPIRED":                  "该任务已超时",
	"RESOURCE_NOT_FOUND":             "请求的内容不存在",
	"CUSTOMER_SERVICE_NOT_FOUND":     "客服已下线或不存在",
	"CUSTOMER_SERVICE_NOT_BOUND":     "客服账号尚未配置",
	"IM_RELATION_PENDING":            "好友申请已发送，请等待客服确认",
	"IM_RELATION_NOT_ALLOWED":        "当前无法与该客服建立会话",
	"IM_SERVICE_UNAVAILABLE":         "客服系统暂不可用，请稍后重试",
	"ACCOUNT_TYPE_INVALID":           "收款账户类型不正确",
	"PAYMENT_ACCOUNT_FIELDS_INVALID": "收款账户信息填写不完整或格式不正确",
	"CURRENCY_INVALID":               "币种参数不正确",
	"WITHDRAWAL_AMOUNT_INVALID":      "取出金额不符合当前规则",
	"RECHARGE_AMOUNT_INVALID":        "储入金额不符合当前规则",
	"RECHARGE_REMARK_INVALID":        "储入备注格式不正确",
	"RECHARGE_VOUCHER_INVALID":       "储入凭证无效，请重新上传",
	"IDEMPOTENCY_KEY_INVALID":        "请求标识无效，请刷新后重试",
	"LEDGER_FILTER_INVALID":          "账变记录筛选条件不正确",
	"WITHDRAWAL_STATUS_INVALID":      "取出状态参数不正确",
	"RECHARGE_STATUS_INVALID":        "储入状态参数不正确",
	"RECHARGE_ORDER_ID_INVALID":      "储入订单参数不正确",
	"WITHDRAWAL_ORDER_ID_INVALID":    "取出订单参数不正确",
	"PAYMENT_ACCOUNT_EXISTS":         "该收款账户已经存在",
	"PAYMENT_ACCOUNT_INVALID":        "收款账户未核验或不可用",
	"WITHDRAWAL_DISABLED":            "取出功能暂未开放",
	"WITHDRAWAL_CHANNEL_UNAVAILABLE": "当前没有可用的取出通道",
	"RECHARGE_CHANNEL_UNAVAILABLE":   "当前没有可用的储入通道",
	"WITHDRAWAL_DAILY_LIMIT_REACHED": "今日取出次数已用完",
	"WITHDRAWAL_ORDER_NOT_FOUND":     "取出订单不存在",
	"RECHARGE_ORDER_NOT_FOUND":       "储入订单不存在",
	"IDEMPOTENCY_CONFLICT":           "请勿重复提交不同的请求",
	"QR_ATTACHMENT_INVALID":          "二维码图片无效，请重新上传",
	"BANNER_POSITION_INVALID":        "轮播图位置参数不正确",
	"CONTENT_KEY_INVALID":            "内容页面参数不正确",
}

func writeSuccess(w http.ResponseWriter, r *http.Request, data any) {
	writeJSON(w, r, http.StatusOK, map[string]any{
		"code": 0, "data": data, "request_id": requestID(r),
		"server_time": time.Now().UTC().Format(time.RFC3339Nano),
	})
}

func writeError(w http.ResponseWriter, r *http.Request, status, code int, reason, message string, details map[string]any) {
	writeJSON(w, r, status, apiError{Code: code, Reason: reason, Message: localizedAPIErrorMessage(reason, message), Details: details,
		RequestID: requestID(r), ServerTime: time.Now().UTC().Format(time.RFC3339Nano)})
}

func localizedAPIErrorMessage(reason, message string) string {
	if localized := apiErrorMessages[reason]; localized != "" {
		return localized
	}
	if strings.IndexFunc(message, func(r rune) bool { return unicode.Is(unicode.Han, r) }) >= 0 {
		return message
	}
	return "请求失败，请稍后重试"
}

func writeJSON(w http.ResponseWriter, r *http.Request, status int, value any) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	if requestID := requestID(r); requestID != "" {
		w.Header().Set("X-Request-ID", requestID)
	}
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(value)
}

func requestID(r *http.Request) string {
	return r.Header.Get("X-Request-ID")
}

func decodeBody(w http.ResponseWriter, r *http.Request, dst any) bool {
	defer r.Body.Close()
	decoder := json.NewDecoder(r.Body)
	decoder.DisallowUnknownFields()
	if err := decoder.Decode(dst); err != nil {
		writeError(w, r, http.StatusBadRequest, 30000, reasonMalformedRequest, "malformed request", nil)
		return false
	}
	return true
}

func methodNotAllowed(w http.ResponseWriter, r *http.Request, allowed ...string) {
	if len(allowed) == 0 {
		allowed = []string{http.MethodPost}
	}
	w.Header().Set("Allow", strings.Join(allowed, ", "))
	writeError(w, r, http.StatusMethodNotAllowed, 30005, reasonMethodNotAllowed, "method not allowed", nil)
}