/**
 * Planungs-KI Phase D: strukturierter Kontext für suggestExerciseAi.
 */

export function buildPickerPlanningContextForAi({
  planningContextSummary = null,
  planningContext = null,
  searchQuery = '',
} = {}) {
  if (!planningContextSummary && !planningContext) return null
  const ctx = {
    source: 'planning_picker',
    search_query: (searchQuery || '').trim() || null,
    unit_title: planningContextSummary?.unit_title || null,
    group_name: planningContextSummary?.group_name || null,
    section_title:
      planningContextSummary?.section_title || planningContext?.sectionTitle || null,
    section_guidance_notes: planningContext?.sectionGuidanceNotes || null,
    section_exercise_count: planningContextSummary?.section_exercise_count ?? null,
    last_section_exercise_title:
      planningContextSummary?.last_section_exercise_title ||
      planningContext?.lastExerciseTitle ||
      null,
    anchor_title: planningContextSummary?.anchor_title || null,
    progression_graph_name: planningContextSummary?.progression_graph_name || null,
    planned_count: planningContextSummary?.planned_count ?? null,
    intent_resolved:
      planningContextSummary?.intent_resolved || planningContext?.intentHint || null,
  }
  return Object.fromEntries(Object.entries(ctx).filter(([, v]) => v != null && v !== ''))
}

function stageSpecForMajorIndex(progressionRoadmap, majorIdx) {
  if (majorIdx == null || !progressionRoadmap) return null
  const specs = progressionRoadmap?.stage_specs
  if (!Array.isArray(specs)) return null
  const hit = specs.find((s) => Number(s.major_step_index) === Number(majorIdx))
  if (!hit) return null
  const majors = progressionRoadmap?.roadmap?.major_steps
  const major =
    Array.isArray(majors) && majors.find((m) => Number(m.index) === Number(majorIdx))
  return major ? { ...hit, phase: hit.phase || major.phase } : hit
}

export function buildPathGapPlanningContextForAi({
  goalQuery = '',
  semanticBrief = null,
  offer = null,
  graphId = null,
  pathSteps = [],
  editableMajorSteps = [],
  progressionRoadmap = null,
  startSituation = '',
  targetState = '',
  roadmapNotes = '',
} = {}) {
  const afterIdx = Number(offer?.insert_after_index)
  const stepA = Number.isFinite(afterIdx) && afterIdx >= 0 ? pathSteps[afterIdx] : null
  const stepB =
    Number.isFinite(afterIdx) && afterIdx >= 0 ? pathSteps[afterIdx + 1] : null
  const majorIdxRaw =
    offer?.roadmap_major_step_index ?? offer?.gap?.roadmap_major_step_index
  const majorIdx =
    majorIdxRaw != null && Number.isFinite(Number(majorIdxRaw)) ? Number(majorIdxRaw) : null
  const majorStep =
    majorIdx != null && editableMajorSteps[majorIdx] ? editableMajorSteps[majorIdx] : null
  const stageSpec = stageSpecForMajorIndex(progressionRoadmap, majorIdx)
  const ga = progressionRoadmap?.goal_analysis || null
  const rs = progressionRoadmap?.resolved_structured || null

  const start =
    (startSituation || '').trim() ||
    rs?.start_situation ||
    ga?.start_assumption ||
    null
  const target =
    (targetState || '').trim() || rs?.target_state || ga?.target_state || null
  const notes = (roadmapNotes || '').trim() || rs?.roadmap_notes || null

  const skillHints = []
  if (Array.isArray(semanticBrief?.must_phrases)) {
    semanticBrief.must_phrases.slice(0, 4).forEach((p) => {
      const s = String(p || '').trim()
      if (s) skillHints.push(s)
    })
  }
  if (Array.isArray(semanticBrief?.development_arc) && semanticBrief.development_arc.length) {
    skillHints.push(
      `Entwicklungsbogen: ${semanticBrief.development_arc.slice(0, 5).join(' → ')}`,
    )
  }

  const ctx = {
    source: 'progression_path_gap_fill',
    goal_query: (goalQuery || '').trim() || null,
    primary_topic: ga?.primary_topic || semanticBrief?.primary_topic || null,
    progression_graph_id: graphId != null ? Number(graphId) : null,
    gap_source: offer?.source || null,
    gap_phase: offer?.phase || offer?.gap?.expected_phase || null,
    roadmap_major_step_index: majorIdx,
    roadmap_phase: majorStep?.phase || stageSpec?.phase || offer?.phase || null,
    roadmap_learning_goal:
      (majorStep?.learning_goal || offer?.title_hint || offer?.gap?.learning_goal || '').trim() ||
      null,
    start_situation: start,
    target_state: target,
    roadmap_notes: notes,
    stage_learning_goal: stageSpec?.learning_goal || null,
    stage_phase: stageSpec?.phase || majorStep?.phase || null,
    stage_exercise_type: stageSpec?.exercise_type || null,
    stage_load_profile: Array.isArray(stageSpec?.load_profile)
      ? stageSpec.load_profile.slice(0, 6)
      : null,
    stage_success_criteria: Array.isArray(stageSpec?.success_criteria)
      ? stageSpec.success_criteria.slice(0, 4)
      : null,
    stage_anti_patterns: Array.isArray(stageSpec?.anti_patterns)
      ? stageSpec.anti_patterns.slice(0, 3)
      : null,
    path_success_criteria: Array.isArray(ga?.success_criteria)
      ? ga.success_criteria.slice(0, 4)
      : null,
    skill_hints: skillHints.length ? skillHints : null,
    neighbor_before_title: stepA?.exerciseTitle || offer?.from_title || null,
    neighbor_after_title: stepB?.exerciseTitle || offer?.to_title || null,
    path_step_count: Array.isArray(pathSteps) ? pathSteps.length : 0,
    major_step_count:
      editableMajorSteps?.length ||
      progressionRoadmap?.major_step_count ||
      progressionRoadmap?.roadmap?.major_steps?.length ||
      null,
  }
  return Object.fromEntries(Object.entries(ctx).filter(([, v]) => v != null && v !== ''))
}

/** Lesbare Zeilen für UI — aus API context_preview oder lokal berechnet. */
export function gapOfferContextDisplayLines(offer, fallbackParams = null) {
  const raw =
    offer?.context_preview ||
    (fallbackParams ? buildPathGapPlanningContextForAi({ offer, ...fallbackParams }) : null)
  if (!raw) return []
  const lines = []
  const push = (label, value) => {
    const v = String(value || '').trim()
    if (v) lines.push({ label, value: v })
  }
  push('Ausgangslage (Pfad)', raw.start_situation)
  push('Gesamtziel (Pfad)', raw.target_state)
  push('Ergänzungen', raw.roadmap_notes)
  push('Stufen-Lernziel', raw.stage_learning_goal || raw.roadmap_learning_goal)
  if (raw.stage_phase) push('Phase', raw.stage_phase)
  if (Array.isArray(raw.stage_load_profile) && raw.stage_load_profile.length) {
    push('Belastung', raw.stage_load_profile.join(', '))
  }
  if (Array.isArray(raw.stage_success_criteria) && raw.stage_success_criteria.length) {
    push('Erfolgskriterien', raw.stage_success_criteria.slice(0, 3).join(' · '))
  }
  if (Array.isArray(raw.skill_hints) && raw.skill_hints.length) {
    push('Fähigkeiten-Fokus', raw.skill_hints.slice(0, 3).join(' · '))
  }
  return lines
}