// Pure mappings from the Go /retrieve response (SDK/RAG-owned; board 2026-07-01 12:25)
// to the FE-facing advisor contract. Kept pure + testable; the orchestration (route.ts) wires them.

import type { Citation, ClarityInfo, EvidenceUnit, Footnote, VisualEvidence } from './contract'

export interface RetrieveClarity {
  mode?: string // 'clarify' | 'answer'
  reason?: string // e.g. 'middle_band_llm_needed'
  concentration?: number
  domain_count?: number
  dominant_context?: string
  candidate_contexts?: { id: string; label: string; hits?: number }[]
}

export interface RetrieveFootnote {
  id?: string
  ref?: string
  number?: number
  regulation_code?: string
  regulation_short?: string
  regulation_name?: string
  section?: string
  text?: string
}

export interface RetrieveResponse {
  evidence?: EvidenceUnit[]
  visual_evidence?: VisualEvidence[]
  footnotes?: RetrieveFootnote[]
  clarity?: RetrieveClarity
  results?: unknown[]
  tables?: unknown[] // C6 — not in the FE contract yet (future TablesPane)
}

/** clarify unless a context was chosen; /retrieve's clarity.mode decides for un-scoped queries. */
export function resolveMode(clarityMode: string | undefined, hasContext: boolean): 'clarify' | 'answer' {
  if (hasContext) return 'answer'
  return clarityMode === 'clarify' ? 'clarify' : 'answer'
}

export function mapClarity(c: RetrieveClarity | undefined, mode: 'clarify' | 'answer'): ClarityInfo {
  return {
    is_underspecified: mode === 'clarify',
    concentration: c?.concentration ?? 0,
    dominant_context: c?.dominant_context,
    suggested_contexts:
      mode === 'clarify' ? (c?.candidate_contexts ?? []).map((cc) => ({ id: cc.id, label: cc.label })) : undefined,
  }
}

export function mapFootnotes(fns: RetrieveFootnote[] | undefined): Footnote[] {
  return (fns ?? []).map((f) => ({
    footnote_id: f.id,
    ref: f.ref ?? (f.number != null ? `Fußnote ${f.number}` : undefined),
    document: f.regulation_short || f.regulation_name || f.regulation_code,
    section: f.section,
    text: f.text,
  }))
}

/** Citations are generated by the orchestration (not by /retrieve): [n] -> nth evidence unit. */
export function buildCitations(evidence: EvidenceUnit[]): Citation[] {
  return evidence.map((e, i) => ({
    citation_id: `c${i + 1}`,
    number: i + 1,
    evidence_id: e.evidence_id,
    document: e.document,
    section: e.section ?? null,
    paragraph: e.paragraph ?? null,
    footnote: null,
    figure: null,
  }))
}

/** Numbered evidence list injected into the L2 prompt so the LLM can cite [n]. */
export function numberedEvidenceForPrompt(evidence: EvidenceUnit[]): string {
  return evidence
    .map((e, i) => {
      const loc = [e.document, e.section, e.paragraph].filter(Boolean).join(' ')
      return `[${i + 1}] ${loc}\n${e.snippet ?? ''}`.trim()
    })
    .join('\n\n')
}

/**
 * Backward-compat discriminator: legacy consumers (e.g. breakpilot-workspace) send `{message}`
 * and read a plain-text stream; the new FE sends `{question}` and expects the JSON contract.
 */
export function isLegacyRequest(body: { question?: unknown; message?: unknown }): boolean {
  return body.question == null && typeof body.message === 'string'
}