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

import { slotsAsPathStepRows } from './progressionGraphDraft.js'

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 majorIndexFromStep(step) {
  const raw = step?.roadmap_major_step_index ?? step?.roadmapMajorStepIndex
  if (raw == null || !Number.isFinite(Number(raw))) return null
  return Number(raw)
}

function priorPathStepsBeforeMajor(pathSteps, majorIdx) {
  if (majorIdx == null || !Number.isFinite(Number(majorIdx))) return []
  const mi = Number(majorIdx)
  return (pathSteps || [])
    .filter((s) => {
      const idx = majorIndexFromStep(s)
      return idx != null && idx < mi
    })
    .sort((a, b) => (majorIndexFromStep(a) || 0) - (majorIndexFromStep(b) || 0))
}

function stepDisplayFields(step) {
  if (!step) return null
  const title = String(step.title || step.exerciseTitle || '').trim()
  const learningGoal = String(
    step.roadmap_learning_goal || step.roadmapLearningGoal || step.learning_goal || '',
  ).trim()
  const phase = String(step.roadmap_phase || step.roadmapPhase || step.phase || '').trim()
  const startState = String(step.roadmap_start_state || step.start_state || '').trim()
  const targetState = String(step.roadmap_target_state || step.target_state || '').trim()
  const criteria = Array.isArray(step.success_criteria)
    ? step.success_criteria.map((x) => String(x || '').trim()).filter(Boolean).slice(0, 4)
    : []
  const majorStepIndex = majorIndexFromStep(step)
  const out = {
    title: title || null,
    learning_goal: learningGoal || null,
    start_state: startState || null,
    target_state: targetState || null,
    phase: phase || null,
    success_criteria: criteria.length ? criteria : null,
    major_step_index: majorStepIndex,
  }
  const hasData = Object.values(out).some((v) => v != null && v !== '')
  return hasData ? out : null
}

export function buildProgressionEntryState({
  majorStepIndex = null,
  priorSteps = [],
  startSituation = '',
  currentStageStart = '',
} = {}) {
  const priorCompact = (priorSteps || [])
    .map(stepDisplayFields)
    .filter(Boolean)

  const achievements = []
  const detailLines = []
  for (const p of priorCompact) {
    if (Array.isArray(p.success_criteria) && p.success_criteria.length) {
      achievements.push(...p.success_criteria)
    } else if (p.learning_goal) {
      achievements.push(p.learning_goal)
    }

    const labelParts = []
    if (p.major_step_index != null) labelParts.push(`Stufe ${p.major_step_index + 1}`)
    if (p.phase) labelParts.push(`(${p.phase})`)
    if (p.title) labelParts.push(`„${p.title}"`)
    const prefix = labelParts.length ? labelParts.join(' ') : 'Vorstufe'
    const achieved =
      p.target_state ||
      (Array.isArray(p.success_criteria) && p.success_criteria.length
        ? p.success_criteria.join('; ')
        : '') ||
      p.learning_goal ||
      ''
    if (achieved) detailLines.push(`${prefix}: erreicht — ${achieved}`)
  }

  let entryState = (currentStageStart || '').trim()
  if (!entryState && priorCompact.length) {
    const immediate = priorCompact[priorCompact.length - 1]
    entryState =
      immediate.target_state ||
      (Array.isArray(immediate.success_criteria) && immediate.success_criteria.length
        ? immediate.success_criteria.join('; ')
        : '') ||
      immediate.learning_goal ||
      ''
  } else if (!entryState && (startSituation || '').trim()) {
    entryState = startSituation.trim()
  }

  if (priorCompact.length && (startSituation || '').trim() && !entryState) {
    detailLines.unshift(`Ausgangsbasis Pfad: ${startSituation.trim()}`)
  }

  const out = {}
  if (entryState) out.entry_state = entryState
  if (detailLines.length) out.entry_state_detail = detailLines.join('\n')
  if (priorCompact.length) out.prior_steps = priorCompact.slice(0, 6)
  if (achievements.length) out.prior_achievements = [...new Set(achievements)].slice(0, 8)
  return out
}

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 = '',
  stageLearningGoalOverride = '',
  gapTrainerSupplements = '',
} = {}) {
  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 priorSteps = majorIdx != null ? priorPathStepsBeforeMajor(pathSteps, majorIdx) : []
  const afterIdx = Number(offer?.insert_after_index)
  const stepA =
    priorSteps.length > 0
      ? priorSteps[priorSteps.length - 1]
      : Number.isFinite(afterIdx) && afterIdx >= 0
        ? pathSteps[afterIdx]
        : null
  const stepB =
    majorIdx != null
      ? (pathSteps || []).find((s) => majorIndexFromStep(s) === majorIdx + 1) ||
        (Number.isFinite(afterIdx) && afterIdx >= 0 ? pathSteps[afterIdx + 1] : null)
      : Number.isFinite(afterIdx) && afterIdx >= 0
        ? pathSteps[afterIdx + 1]
        : 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 entryState = buildProgressionEntryState({
    majorStepIndex: majorIdx,
    priorSteps,
    startSituation: start,
    currentStageStart: stageSpec?.start_state || '',
  })

  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:
      (stageLearningGoalOverride || '').trim() || stageSpec?.learning_goal || null,
    stage_start_state: stageSpec?.start_state || null,
    stage_target_state: stageSpec?.target_state || null,
    gap_trainer_supplements: (gapTrainerSupplements || '').trim() || 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 || stepA?.title || offer?.from_title || null,
    neighbor_after_title: stepB?.exerciseTitle || stepB?.title || offer?.to_title || null,
    ...entryState,
    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('Eingangszustand (Vorstufen)', raw.entry_state)
  if (raw.entry_state_detail && raw.entry_state_detail !== raw.entry_state) {
    push('Bisheriger Pfad', raw.entry_state_detail)
  }
  if (Array.isArray(raw.prior_achievements) && raw.prior_achievements.length) {
    push('Erreichte Voraussetzungen', raw.prior_achievements.slice(0, 6).join(' · '))
  }
  push('Ausgangslage (gesamter 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(' · '))
  }
  if (Array.isArray(raw.expected_skills) && raw.expected_skills.length) {
    const names = raw.expected_skills
      .map((s) => String(s?.skill_name || '').trim())
      .filter(Boolean)
      .slice(0, 5)
    if (names.length) push('Erwartete Fähigkeiten', names.join(' · '))
  }
  push('Trainer-Ergänzungen', raw.gap_trainer_supplements)
  return lines
}

/** Zieltext für KI aus Slot-Kontext (Graph-Editor ohne API-Offer). */
export function buildSlotGapGoalForAi(draft, slotIndex, { goalQuery = '' } = {}) {
  const slot = draft?.slots?.[slotIndex]
  if (!slot) return ''
  const pathSteps = slotsAsPathStepRows(draft)
  const majorIdx = slot.majorStepIndex
  const priorSteps = priorPathStepsBeforeMajor(pathSteps, majorIdx)
  const start = (draft.startSituation || '').trim()
  const stageSpec =
    majorIdx != null && draft.progressionRoadmap
      ? stageSpecForMajorIndex(draft.progressionRoadmap, majorIdx)
      : null
  const entry = buildProgressionEntryState({
    majorStepIndex: majorIdx,
    priorSteps,
    startSituation: start,
    currentStageStart: stageSpec?.start_state || '',
  })
  const parts = [
    goalQuery ? `Planungsziel (gesamter Pfad): ${goalQuery}` : '',
    entry.entry_state
      ? `Eingangszustand (erreichte Voraussetzungen): ${entry.entry_state}`
      : start
        ? `Ausgangslage (Pfad): ${start}`
        : '',
    entry.entry_state_detail && entry.entry_state_detail !== entry.entry_state
      ? `Bisheriger Pfad:\n${entry.entry_state_detail}`
      : '',
    (slot.learning_goal || '').trim()
      ? `Lernziel dieser Roadmap-Stufe: ${(slot.learning_goal || '').trim()}`
      : '',
    (slot.phase || '').trim() ? `Entwicklungsphase: ${slot.phase}` : '',
    'Die Übung baut didaktisch auf den Vorstufen auf — Voraussetzungen explizit benennen, messbares Stufenziel.',
  ].filter(Boolean)
  return parts.join('\n\n').trim()
}

export function initialStageLearningGoalFromOffer(offer, fallbackParams = null) {
  const lines = gapOfferContextDisplayLines(offer, fallbackParams)
  const hit = lines.find((l) => l.label === 'Stufen-Lernziel')
  return hit?.value || (offer?.title_hint || '').trim()
}