import cloud from '@lafjs/cloud'
const db = cloud.database();

const COLLECTION = "ab_config";
const DEFAULT_ADMIN_TOKEN = "abtest-admin-token";

export default async function (ctx: FunctionContext) {
  const action = ctx.body?.action || ctx.query?.action || "list";
  const adminToken = ctx.body?.adminToken || ctx.query?.adminToken;
  if (!checkAdminToken(adminToken)) {
    return { code: 0, data: null, msg: "unauthorized" };
  }

  switch (action) {
    case "list":
      return await listConfigs();
    case "save":
      return await saveConfig(ctx.body?.config);
    case "disable":
      return await setEnabled(ctx.body?.experimentId, false);
    case "enable":
      return await setEnabled(ctx.body?.experimentId, true);
    case "delete":
      return await deleteConfig(ctx.body?.experimentId);
    default:
      return { code: 0, data: null, msg: "invalid action" };
  }
}

function checkAdminToken(adminToken: string) {
  const env = (globalThis as any).process?.env || {};
  const token = env.AB_ADMIN_TOKEN || DEFAULT_ADMIN_TOKEN;
  return !!adminToken && adminToken === token;
}

async function listConfigs() {
  const ret = await db.collection(COLLECTION).get();
  return { code: 1, data: ret.data || [], msg: "ok" };
}

async function saveConfig(config: any) {
  if (typeof config == "string") {
    try {
      config = JSON.parse(config);
    } catch {
      return { code: 0, data: null, msg: "config json invalid" };
    }
  }
  if (Array.isArray(config)) {
    const list = [];
    for (let i = 0; i < config.length; i++) {
      const ret = await saveOneConfig(config[i]);
      if (ret.code !== 1) {
        return ret;
      }
      list.push(ret.data);
    }
    return { code: 1, data: list, msg: "saved" };
  }
  return await saveOneConfig(config);
}

async function saveOneConfig(config: any) {
  const error = validateConfig(config);
  if (error) {
    return { code: 0, data: null, msg: error };
  }

  const now = Date.now();
  const data = {
    experimentId: config.experimentId,
    layer: String(config.layer || ""),
    name: config.name || config.experimentId,
    enabled: config.enabled !== false,
    resetAssignments: config.resetAssignments === true,
    startTime: Number(config.startTime || 0),
    endTime: Number(config.endTime || 0),
    variants: normalizeVariants(config.variants),
    updatedAt: now,
  };

  const old = await db.collection(COLLECTION).where({ experimentId: data.experimentId }).getOne();
  if (old.data) {
    await db.collection(COLLECTION).where({ _id: old.data._id }).update(data);
    return { code: 1, data: data, msg: "updated" };
  }

  await db.collection(COLLECTION).add({ ...data, createdAt: now });
  return { code: 1, data: data, msg: "created" };
}

async function setEnabled(experimentId: string, enabled: boolean) {
  if (!experimentId) {
    return { code: 0, data: null, msg: "experimentId required" };
  }
  const ret = await db.collection(COLLECTION).where({ experimentId: experimentId }).update({
    enabled: enabled,
    updatedAt: Date.now(),
  });
  return { code: 1, data: ret, msg: "ok" };
}

async function deleteConfig(experimentId: string) {
  if (!experimentId) {
    return { code: 0, data: null, msg: "experimentId required" };
  }
  const ret = await db.collection(COLLECTION).where({ experimentId: experimentId }).remove({ multi: true });
  return { code: 1, data: ret, msg: "ok" };
}

function validateConfig(config: any) {
  if (!config) {
    return "config required";
  }
  if (!config.experimentId) {
    return "experimentId required";
  }
  if (!config.layer) {
    return "layer required";
  }
  if (!Array.isArray(config.variants) || config.variants.length < 2) {
    return "variants length must be >= 2";
  }

  let total = 0;
  const groups = {};
  for (let i = 0; i < config.variants.length; i++) {
    const variant = config.variants[i];
    if (!variant.group) {
      return "variant.group required";
    }
    if (groups[variant.group]) {
      return "variant.group duplicated";
    }
    groups[variant.group] = true;
    const ratio = Number(variant.ratio);
    if (!(ratio > 0)) {
      return "variant.ratio must be positive";
    }
    total += ratio;
  }
  if (total <= 0) {
    return "ratio total must be positive";
  }
  if (config.startTime && config.endTime && Number(config.endTime) <= Number(config.startTime)) {
    return "endTime must be greater than startTime";
  }
  return "";
}

function normalizeVariants(variants: any[]) {
  return variants.map(variant => ({
    group: variant.group,
    ratio: Number(variant.ratio),
  }));
}