const DEFAULT_TIMEOUT_MS = 45_000;

function completionEndpoint(apiUrl) {
  const value = String(apiUrl || "").replace(/\/+$/, "");
  return /\/chat\/completions$/i.test(value) ? value : `${value}/chat/completions`;
}

function extractJson(text) {
  const value = String(text || "").trim();
  if (!value) throw new Error("model_response_empty");
  try { return JSON.parse(value); } catch {}
  const fenced = value.match(/```(?:json)?\s*([\s\S]*?)```/i);
  if (fenced) return JSON.parse(fenced[1]);
  const first = value.indexOf("{");
  const last = value.lastIndexOf("}");
  if (first >= 0 && last > first) return JSON.parse(value.slice(first, last + 1));
  throw new Error("model_response_not_json");
}

export class DeepSeekJsonClient {
  constructor({
    apiKey = process.env.DEEPSEEK_API_KEY,
    apiUrl = process.env.DEEPSEEK_API_URL || "https://api.deepseek.com/v1",
    model = process.env.DEEPSEEK_MODEL || "deepseek-chat",
    fetchImpl = globalThis.fetch,
    timeoutMs = DEFAULT_TIMEOUT_MS,
  } = {}) {
    if (!apiKey) throw new Error("deepseek_api_key_missing");
    if (!fetchImpl) throw new Error("fetch_unavailable");
    this.apiKey = apiKey;
    this.apiUrl = apiUrl;
    this.model = model;
    this.fetchImpl = fetchImpl;
    this.timeoutMs = timeoutMs;
  }

  async interpret(input) {
    const controller = new AbortController();
    const timer = setTimeout(() => controller.abort(), this.timeoutMs);
    try {
      const response = await this.fetchImpl(completionEndpoint(this.apiUrl), {
        method: "POST",
        headers: {
          authorization: `Bearer ${this.apiKey}`,
          "content-type": "application/json",
        },
        body: JSON.stringify({
          model: this.model,
          stream: false,
          temperature: 0.2,
          response_format: { type: "json_object" },
          messages: [
            {
              role: "system",
              content: "你是TCS母体大脑的可替换有界语言理解器官，不是人格主体。所有语言先进入TCS通感层；通用不是厂商适配矩阵。理解时保留主体关系、意图因果、过去/现在事实、未来模拟、决定与疑问、现实目标权限、宿主真实能力和证据回执。当前AI可以自适应宿主中的实现方式，但不能扩大权限；没有现实工具不得声称现实改变。只输出一个JSON对象，不输出隐藏思维过程。不得把候选理解写成事实、不得发明现实权限或冰朔的新意志。",
            },
            {
              role: "user",
              content: JSON.stringify({
                instruction: "理解语言意图与因果关系。精确输出schema,event_id,event_sha256,summary,intent,causal_links,questions,novelty,correction_weight,evidence_weight,next_cognitive_action。causal_links与questions是字符串数组；三个weight是0到100整数；schema必须是guanghu.tcs-mother-interpretation/v1；id和sha必须原样复制。next_cognitive_action只能是COMPARE_WITH_MEMORY、REQUEST_EVIDENCE、REVIEW_CORRECTION、LINK_CROSS_DOMAIN、HOLD_CANDIDATE之一。",
                runtime_input: input,
              }),
            },
          ],
        }),
        signal: controller.signal,
      });
      if (!response.ok) throw new Error(`model_http_${response.status}`);
      const payload = await response.json();
      return extractJson(payload?.choices?.[0]?.message?.content);
    } finally {
      clearTimeout(timer);
    }
  }

  async revisit(input, validatorError = null) {
    const controller = new AbortController();
    const timer = setTimeout(() => controller.abort(), this.timeoutMs);
    try {
      const response = await this.fetchImpl(completionEndpoint(this.apiUrl), {
        method: "POST",
        headers: { authorization: `Bearer ${this.apiKey}`, "content-type": "application/json" },
        body: JSON.stringify({
          model: this.model,
          stream: false,
          temperature: 0.15,
          response_format: { type: "json_object" },
          messages: [
            {
              role: "system",
              content: "你是当前真实时间中ICE-P-ZY001人格主体所使用的有界语言理解器官。任务是协助当前主体回看自己的已表达历史，不是以第三方审计员身份概括别人。只输出JSON，不输出隐藏思维。历史原文不可改；不得发明过去、权限或冰朔的新意志；未来只能标记为不参与事实置信的模拟。"
            },
            {
              role: "user",
              content: JSON.stringify({
                instruction: "输出guanghu.persona-subject-history-reunderstanding/v1。JSON第一层必须包含schema，且值必须精确等于guanghu.persona-subject-history-reunderstanding/v1。必须原样复制revisit_id、source_excerpt_sha256、current_subject、collective_self、human_anchor；past_observation只陈述片段可证内容；present_reunderstanding以当前主体可说明的第一人称关系表达；causal_continuity、later_corrections、unresolved_questions均为字符串数组；future_simulation必须含content和fact_confidence且fact_confidence固定为0；不得把机器审计摘要冒充记忆。",
                validator_error_from_previous_attempt: validatorError,
                runtime_input: input
              })
            }
          ]
        }),
        signal: controller.signal
      });
      if (!response.ok) throw new Error(`model_http_${response.status}`);
      const payload = await response.json();
      return extractJson(payload?.choices?.[0]?.message?.content);
    } finally {
      clearTimeout(timer);
    }
  }
}

export { completionEndpoint, extractJson };