import { AnthropicBedrock } from '@anthropic-ai/bedrock-sdk'

/**
 * Extends AnthropicBedrock to work around an upstream bug where the SDK
 * re-plants the `anthropic-beta` HTTP header value into the request body
 * as `anthropic_beta`. Bedrock's Opus 4.7 endpoint rejects any request with
 * `anthropic_beta` in the body with a 400 "invalid beta flag" error.
 *
 * Source of the bug (SDK 0.26.4, still present through 0.28.1):
 *   node_modules/@anthropic-ai/bedrock-sdk/client.js lines 122-127
 *   (TS source: packages/bedrock-sdk/src/client.ts lines 193-198)
 *
 * Related upstream issue: anthropics/claude-code#49238 (opened 2026-04-16).
 *
 * Fix strategy: let super.buildRequest do its work, then strip
 * `body.anthropic_beta` from the resulting Request before the SDK computes
 * the AWS SigV4 signature (signing happens downstream of buildRequest, so
 * the signature hashes the cleaned body — no 403 risk). The `anthropic-beta`
 * HTTP header remains intact (base SDK placed it there from the `betas:`
 * parameter), so beta flags still reach the API the way Bedrock accepts them.
 *
 * When upstream ships a fix, verify the probe in scripts/probe-bedrock-beta-fix.ts
 * shows "bug reproduced: false", then delete this class and change
 * `services/api/client.ts` to instantiate `AnthropicBedrock` directly.
 */
type BuildRequestArg = Parameters<AnthropicBedrock['buildRequest']>[0]
type BuildRequestRet = Awaited<ReturnType<AnthropicBedrock['buildRequest']>>

export class BedrockClient extends AnthropicBedrock {
  async buildRequest(options: BuildRequestArg): Promise<BuildRequestRet> {
    const req = await super.buildRequest(options)

    const inner = (
      req as unknown as { req?: { body?: unknown; headers?: unknown } }
    )?.req
    if (!inner || typeof inner.body !== 'string' || inner.body.length === 0) {
      return req
    }

    let parsed: Record<string, unknown>
    try {
      parsed = JSON.parse(inner.body) as Record<string, unknown>
    } catch {
      return req
    }
    if (!('anthropic_beta' in parsed)) {
      return req
    }

    delete parsed.anthropic_beta
    const cleanedBody = JSON.stringify(parsed)
    inner.body = cleanedBody

    const byteLen = String(new TextEncoder().encode(cleanedBody).length)
    const h = inner.headers
    if (typeof Headers !== 'undefined' && h instanceof Headers) {
      if (h.has('content-length')) h.set('content-length', byteLen)
    } else if (h && typeof h === 'object') {
      const asDict = h as Record<string, string>
      if ('content-length' in asDict) asDict['content-length'] = byteLen
    }

    return req
  }
}