// Adapter: RAG/compiler output -> the structured AdvisorEvidenceMeta the Evidence Workspace renders.
// This is the ONLY place that maps backend shapes to the frontend envelope. The frontend never
// parses the answer text — all structure originates here from structured fields.

import type {
  AdvisorEvidenceMeta,
  FigureUnit,
  FootnoteUnit,
  KnowledgeUnit,
  RegulationRef,
} from './evidence'
import { deriveStats } from './evidence'
import type { SdkRagResult } from '../agents/advisor-rag'

/** Provisional raw figure (C8) shape — reconcile with the RAG-ingestion contract (board). */
export interface RawFigure {
  figure_id?: string
  id?: string
  label?: string // "Abbildung 3"
  caption?: string
  topic?: string
  regulation_code?: string
  regulation_short?: string
  regulation_name?: string
  section?: string
  vision_summary?: string
  description?: string
  image_url?: string
  url?: string
}

/** Provisional raw footnote (C-FN) shape — reconcile with the RAG-ingestion contract (board). */
export interface RawFootnote {
  id?: string
  ref?: string
  number?: string | number
  regulation_code?: string
  regulation_short?: string
  regulation_name?: string
  section?: string
  text?: string
}

export interface RawEvidenceInput {
  results?: SdkRagResult[]
  figures?: RawFigure[]
  footnotes?: RawFootnote[]
}

function regulationRef(
  code?: string,
  name?: string,
  short?: string,
): RegulationRef {
  return {
    code: (code || short || name || 'unknown').toLowerCase().replace(/\s+/g, '_'),
    name: name || undefined,
    short: short || name || code || 'Quelle',
  }
}

function truncate(text: string, max = 240): string {
  const t = text.trim().replace(/\s+/g, ' ')
  return t.length > max ? `${t.slice(0, max - 1)}…` : t
}

function toKnowledgeUnit(r: SdkRagResult, idx: number): KnowledgeUnit | null {
  const regulation = regulationRef(r.regulation_code, r.regulation_name, r.regulation_short)
  const section = r.is_recital
    ? `Erwägungsgrund ${r.article ?? ''}`.trim()
    : r.article || undefined
  const label = r.article_label?.trim() || undefined
  // Drop empty placeholders: a unit needs at least a label or a section to be meaningful.
  if (!label && !section && !regulation.name && regulation.short === 'Quelle') return null
  return {
    id: `src-${idx}`,
    regulation,
    section,
    paragraph: r.paragraph || undefined,
    subsection: r.sub || undefined,
    label,
    score: typeof r.score === 'number' ? r.score : undefined,
    snippet: r.text ? truncate(r.text) : undefined,
    open: r.source_url ? { originalUrl: r.source_url } : undefined,
  }
}

function dedupeKey(u: KnowledgeUnit): string {
  return [u.regulation.code, u.section, u.paragraph, u.subsection, u.label]
    .map((x) => x || '')
    .join('|')
}

function toFigureUnit(f: RawFigure, idx: number): FigureUnit | null {
  const id = f.figure_id || f.id
  const imageUrl = f.image_url || f.url
  if (!id && !imageUrl && !f.label) return null
  return {
    id: id || `fig-${idx}`,
    label: f.label || `Abbildung ${idx + 1}`,
    caption: f.caption || undefined,
    topic: f.topic || undefined,
    source: regulationRef(f.regulation_code, f.regulation_name, f.regulation_short),
    section: f.section || undefined,
    visionSummary: f.vision_summary || f.description || undefined,
    imageUrl: imageUrl || undefined,
  }
}

function toFootnoteUnit(f: RawFootnote, idx: number): FootnoteUnit | null {
  const ref = f.ref || (f.number != null ? `Fußnote ${f.number}` : undefined)
  if (!ref && !f.text) return null
  return {
    id: f.id || `fn-${idx}`,
    ref: ref || `Fußnote ${idx + 1}`,
    source: regulationRef(f.regulation_code, f.regulation_name, f.regulation_short),
    section: f.section || undefined,
    text: f.text || undefined,
  }
}

/**
 * Build the structured evidence meta. Sources are deduped (same citation retrieved multiple
 * times collapses to one, keeping the highest score) and order is preserved by score.
 */
export function adaptEvidence(input: RawEvidenceInput): AdvisorEvidenceMeta {
  const seen = new Map<string, KnowledgeUnit>()
  ;(input.results || []).forEach((r, i) => {
    const unit = toKnowledgeUnit(r, i)
    if (!unit) return
    const key = dedupeKey(unit)
    const existing = seen.get(key)
    if (!existing || (unit.score ?? 0) > (existing.score ?? 0)) seen.set(key, unit)
  })
  const sources = [...seen.values()].sort((a, b) => (b.score ?? 0) - (a.score ?? 0))
  const figures = (input.figures || [])
    .map(toFigureUnit)
    .filter((x): x is FigureUnit => x !== null)
  const footnotes = (input.footnotes || [])
    .map(toFootnoteUnit)
    .filter((x): x is FootnoteUnit => x !== null)

  const meta = { sources, figures, footnotes }
  return { ...meta, stats: deriveStats(meta) }
}