// Strip request params a given provider/model rejects upstream (e.g. HTTP 400).
// Config-driven: add a rule instead of scattering `delete body.x` across executors.

// Each rule: optional provider, regex match on model, list of params to drop.
// A param is removed only when it is present (!== undefined).
const STRIP_RULES = [
  // claude-opus-4 series: temperature is deprecated (Anthropic 400). #1748
  { match: /claude-opus-4/i, drop: ["temperature"] },
  // GitHub Copilot gpt-5.4: temperature unsupported.
  { provider: "github", match: /gpt-5\.4/i, drop: ["temperature"] },
  // GitHub Copilot Claude (except opus/sonnet 4.6): thinking + reasoning_effort rejected. #713
  { provider: "github", match: (m) => /claude/i.test(m) && !/claude.*(opus|sonnet).*4\.6/i.test(m), drop: ["thinking", "reasoning_effort"] },
  // Cloudflare Workers AI: content must be plain string, rejects OpenAI content-part array (#1926)
  { provider: "cloudflare-ai", flattenContent: true },
];

// Test a rule's match (regex or predicate) against the model id.
function matches(rule, model) {
  return typeof rule.match === "function" ? rule.match(model) : rule.match.test(model);
}

// Remove unsupported params from body in place; returns body.
export function stripUnsupportedParams(provider, model, body) {
  if (!model || !body || typeof body !== "object") return body;
  for (const rule of STRIP_RULES) {
    if (rule.provider && rule.provider !== provider) continue;
    if (!matches(rule, model)) continue;
    for (const key of rule.drop) {
      if (body[key] !== undefined) delete body[key];
    }
    // CF Workers AI oneOf root schema only accepts content as plain string (#1926)
    if (rule.flattenContent && Array.isArray(body.messages)) {
      for (const msg of body.messages) {
        if (msg && Array.isArray(msg.content)) {
          msg.content = msg.content
            .map(b => (b?.type === "text" && typeof b.text === "string") ? b.text : "")
            .join("");
        }
      }
    }
  }
  return body;
}