import type { AdminChannelRecord } from "../../../lib/types";
import { PLATFORM_FIELDS } from "../channelFields";
import { defaultSelection } from "../channelFieldRules";
import { channelPersonaOf } from "./channelPersona";
import type { ChannelConfigInitial } from "../channelConfigForm";

/** Platform part of an adapter name ("kook:conf0" → "kook"). */
export function platformOf(name: string): string {
  return name.split(":")[0];
}

/** Adapter (platform:account) name for one account config. The bridge registers a
 * channels.json account as "kook:conf0" (env single-account = bare platform), so a
 * config id of "default"/"" maps to the bare platform name. */
export function adapterNameOf(platform: string, accountId?: string): string {
  const id = accountId?.trim();
  return id && id !== "default" ? `${platform}:${id}` : platform;
}

/** Open-config target: the platform + the prefill bundle for its form. */
export interface CfgTarget {
  platform: string;
  initial: ChannelConfigInitial;
}

/** 后端对 token/secret/key 类键只下发掩码（`runtimeconfig.Masked`：`****` + 末 4 位）。
 *  掩码值**绝不能回填到表单**：一次「打开就保存」会把 `****abcd` 当成真实 token 写回，
 *  静默毁掉已配置的凭据。旧后端还用过「…（已配置）」这种文字掩码，一并容忍。 */
export function isMaskedSecret(value: unknown): boolean {
  if (typeof value !== "string") return false;
  return value.startsWith("****") || value.includes("（已配置");
}

/** 盘上该键是否已有非空值（不回填掩码原文，但仍要让面板知道「已配置」）。 */
function hasStoredValue(raw: unknown): boolean {
  if (raw === null || raw === undefined) return false;
  if (typeof raw === "string") return raw.trim() !== "";
  return true;
}

/** Build the config-form prefill from a platform name and the channel records.
 *  Do NOT put the masked placeholder into `token`: it would be written back as
 *  the real bot_token (overwriting the stored secret with a demo string). Keep
 *  token empty (save omits it → keeps the existing secret) and show a hint.
 *
 *  平台字段同理：掩码值不回填，只记进 `configuredKeys`（表单据此显示「已配置、留空不
 *  改动」并把它当作需求已满足）；下拉型选择器（transport/mode）在盘上缺值时填默认值，
 *  这样打开表单第一眼看到的组合就是适配器真正会用的那个。 */
export function buildCfgTarget(name: string, records: AdminChannelRecord[], accountId?: string): CfgTarget {
  const plat = platformOf(name);
  const accts = records.find((c) => platformOf(c.name) === plat)?.accounts ?? [];
  // 指定账号优先（多账号平台逐条编辑）；未指定时退回第一个，与旧行为一致。
  const acct = (accountId ? accts.find((a) => a.id === accountId) : undefined) ?? accts[0];
  const acctCfg = acct?.config ?? {};
  const hasToken = typeof acctCfg.bot_token === "string" && acctCfg.bot_token && !isMaskedSecret(acctCfg.bot_token);
  const fieldDefs = PLATFORM_FIELDS[plat] ?? [];
  const platVals: Record<string, string> = {};
  const configuredKeys: string[] = [];
  for (const f of fieldDefs) {
    const raw = acctCfg[f.key];
    if (!hasStoredValue(raw)) continue;
    configuredKeys.push(f.key);
    if (isMaskedSecret(raw)) continue;
    platVals[f.key] = String(raw);
  }
  const fallback = defaultSelection(plat);
  for (const f of fieldDefs) {
    if (platVals[f.key] !== undefined) continue;
    const def = f.defaultValue ?? "";
    if (def !== "") platVals[f.key] = def;
  }
  // 选择器缺省兜底：即使平台没给字段声明缺省值，也让「当前模式」有值可判定。
  if (fallback.transport && platVals.transport === undefined) platVals.transport = fallback.transport;
  if (fallback.mode && platVals.mode === undefined) platVals.mode = fallback.mode;
  return {
    platform: plat,
    initial: {
      accountId: acct?.id ?? "",
      savedId: acct?.id ?? "",
      tokenHint: hasToken ? "已配置（仅掩码显示），留空则不改动；如需更换请重新输入。" : "",
      baseURL: typeof acctCfg.base_url === "string" ? acctCfg.base_url : "",
      platVals,
      configuredKeys,
      allowGroups: (acct?.allowGroups ?? []).join(","),
      denyGroups: (acct?.denyGroups ?? []).join(","),
      allowUsers: (acct?.allowUsers ?? []).join(","),
      denyUsers: acct?.denyUsers ? (Array.isArray(acct.denyUsers) ? acct.denyUsers.join(",") : "") : "",
      // 限流三个字段读**账号顶层**，不是 `config`（见 LIMIT_KEYS 的说明）。
      groupMsgPerMin: limitInitialOf(acct?.groupMsgPerMin),
      msgPerMin: limitInitialOf(acct?.msgPerMin),
      maxMessages: limitInitialOf(acct?.maxMessages),
      personaId: channelPersonaOf(acct),
    },
  };
}

/** 限流 / 会话额度的三个字段名（design/12 §6 策略三/四）。回显、写回与表单共用这一份，
 *  避免两处清单漂移。
 *
 *  ⚠️ 线上它们是**账号顶层**字段（`AdminChannelAccount.GroupMsgPerMin/MsgPerMin/
 *  MaxMessages`，见 `internal/services/gateway/admin_write_channel_config.go` 的
 *  `adminChannelAccountOf`），**不在 `config` 里** —— 从 `config` 读永远读不到：回显空
 *  ⇒ 保存时按「未设置」写回 0 ⇒ **静默清掉主人已设的限流**。 */
export const LIMIT_KEYS = ["groupMsgPerMin", "msgPerMin", "maxMessages"] as const;

/** 限流字段名。 */
export type LimitKey = (typeof LIMIT_KEYS)[number];

/** 已设限额 → 表单回显：缺省与 `0` 都渲染成空（后端 `omitempty` ⇒ 两者在盘上等价）。
 *  非零值**原样回传**，这样「没动过的字段」保存时原样送回，不会把已存限额写没。 */
function limitInitialOf(v: number | undefined): string {
  return v === undefined || v === 0 ? "" : String(v);
}

/** 表单限流值 → 请求体取值：
 *  - 留空 → `undefined`：该键**不进请求体**（后端 int 契约下省略 = 0 = 未设置）；
 *  - 整数（含负值）→ 该数值；
 *  - 其它（小数 / 非数字）→ `null`，调用方报错并**中止保存** —— `Number("x")` 是 NaN、
 *    序列化成 `null`，后端 int 收到 `null` 静默落 0，同样会清空已设限额。
 *
 *  数值语义以 `internal/services/channelbridge/flowgate.go` 的 `flowOrDefault` 为准：
 *  **0 = 保护性默认**（群 6 条/分、待处理上限 50）、**负值 = 关闭限制**；`msgPerMin` 只认正值。 */
export function limitFieldValue(raw: string): number | undefined | null {
  const t = raw.trim();
  if (!t) return undefined;
  return /^-?\d+$/.test(t) ? Number(t) : null;
}

/** 表单三个限流字段 → PUT 请求体片段。任一字段非法即整单拒绝（绝不发半份请求体，
 *  也绝不用 0 代替「未设置」）。 */
export function limitRequestBody(
  fields: Record<LimitKey, string>
): { ok: true; body: Partial<Record<LimitKey, number>> } | { ok: false; error: string } {
  const body: Partial<Record<LimitKey, number>> = {};
  for (const key of LIMIT_KEYS) {
    const value = limitFieldValue(fields[key]);
    if (value === null) return { ok: false, error: `${key} 需为整数（留空 = 未设置，负值 = 关闭限制）` };
    if (value !== undefined) body[key] = value;
  }
  return { ok: true, body };
}

/** The set of platforms that have at least one configured account. */
export function configuredPlatforms(records: AdminChannelRecord[]): AdminChannelRecord[] {
  return records.filter((c) => (c.accounts?.length ?? 0) > 0);
}

/** Total configured accounts across all platforms. */
export function configuredAccountCount(records: AdminChannelRecord[]): number {
  return configuredPlatforms(records).reduce((n, c) => n + (c.accounts?.length ?? 0), 0);
}