/**
 * KI-gestützte Schnellanlage / Vorschau (Planung / ExercisePickerModal).
 */
import { stripHtmlToText } from './htmlUtils'
import { normalizeSkillLevelSlug, formatSkillLevelSlug } from '../constants/skillLevels'
import {
  EXERCISE_SKILL_INTENSITY_DEFAULT,
  normalizeExerciseSkillIntensity,
  formatExerciseSkillIntensityLabel,
} from '../constants/exerciseSkillIntensity'

export const INSTRUCTION_AI_FIELD_DEFS = [
  { key: 'goal', label: 'Ziel' },
  { key: 'execution', label: 'Durchführung' },
  { key: 'preparation', label: 'Vorbereitung / Aufbau' },
  { key: 'trainer_notes', label: 'Hinweise für Trainer' },
]

function escapeHtmlText(s) {
  return String(s)
    .replace(/&/g, '&')
    .replace(/</g, '&lt;')
    .replace(/>/g, '&gt;')
    .replace(/"/g, '&quot;')
}

/** Suchstring → Titel + Skizze für Schnellanlage (erste Zeile / Satz als Titel). */
export function parseSearchQueryForQuickCreate(searchText) {
  const raw = String(searchText || '').trim()
  if (!raw) return { title: '', sketch: '' }

  const lines = raw.split(/\n/).map((l) => l.trim()).filter(Boolean)
  if (lines.length >= 2) {
    return {
      title: lines[0].slice(0, 300),
      sketch: lines.slice(1).join('\n'),
    }
  }

  const single = lines[0] || raw
  if (single.length <= 80) {
    return { title: single.slice(0, 300), sketch: single }
  }

  const sentenceMatch = single.match(/^(.{10,120}?[.!?;:])\s+(.+)$/s)
  if (sentenceMatch) {
    return {
      title: sentenceMatch[1].trim().slice(0, 300),
      sketch: single,
    }
  }

  const words = single.split(/\s+/).filter(Boolean)
  const titleWordCount = Math.min(8, Math.max(3, Math.ceil(words.length / 3)))
  const title = words.slice(0, titleWordCount).join(' ').slice(0, 120)
  return { title, sketch: single }
}

/** Plaintext → Absätze für RichTextEditor / API. */
export function aiPlainTextToMinimalHtml(text) {
  const raw = String(text || '').trim()
  if (!raw) return ''
  const parts = raw.split(/\n+/).map((p) => p.trim()).filter(Boolean)
  const paras = parts.length ? parts : [raw]
  return paras.map((p) => `<p>${escapeHtmlText(p)}</p>`).join('')
}

export function normalizeAiSkillRowFromApi(sug) {
  const sid = Number(sug?.skill_id)
  if (!Number.isFinite(sid) || sid < 1) return null
  return {
    skill_id: sid,
    intensity: normalizeExerciseSkillIntensity(sug.intensity) || EXERCISE_SKILL_INTENSITY_DEFAULT,
    required_level: normalizeSkillLevelSlug(sug.required_level) || 'grundlagen',
    target_level:
      normalizeSkillLevelSlug(sug.target_level) ||
      normalizeSkillLevelSlug(sug.required_level) ||
      'grundlagen',
    is_primary: !!sug.is_primary,
    ai_suggested: true,
  }
}

/** Vorschau für Schnellanlage: Kurzfassung + Anleitung + Fähigkeiten. */
export function buildQuickCreateAiPreview(apiRes, { sketchPlain = '' } = {}) {
  const sketchHtml = aiPlainTextToMinimalHtml(sketchPlain)
  const snapshotInstructions = {
    goal: sketchHtml,
    execution: '',
    preparation: '',
    trainer_notes: '',
  }

  let summaryAfterHtml = null
  let summaryAfterPlain = ''
  if (apiRes?.summary?.text) {
    summaryAfterPlain = String(apiRes.summary.text).trim()
    if (summaryAfterPlain) {
      summaryAfterHtml = aiPlainTextToMinimalHtml(apiRes.summary.text)
    }
  }

  const skillChoices = []
  if (Array.isArray(apiRes?.skills)) {
    for (const sug of apiRes.skills) {
      const after = normalizeAiSkillRowFromApi(sug)
      if (!after) continue
      skillChoices.push({
        key: String(after.skill_id),
        skill_id: after.skill_id,
        kind: 'add',
        before: null,
        after,
        include: true,
      })
    }
  }

  const instructionChoices = []
  const fields = apiRes?.instructions?.fields || {}
  for (const def of INSTRUCTION_AI_FIELD_DEFS) {
    const afterHtml = fields[def.key]
    if (!afterHtml || !String(afterHtml).trim()) continue
    const beforeHtml = snapshotInstructions[def.key] || ''
    instructionChoices.push({
      key: def.key,
      field: def.key,
      label: def.label,
      beforePlain: stripHtmlToText(beforeHtml).trim(),
      afterHtml: String(afterHtml),
      afterPlain: stripHtmlToText(afterHtml).trim(),
      include: true,
    })
  }

  const hasSummaryProposal = !!summaryAfterHtml
  const hasSkillChoices = skillChoices.length > 0
  const hasInstructionChoices = instructionChoices.length > 0

  return {
    mode: 'quick_create',
    applySummary: hasSummaryProposal,
    summaryBeforePlain: stripHtmlToText(sketchPlain).trim(),
    summaryAfterPlain,
    summaryAfterHtml,
    skillChoices,
    instructionChoices,
    hasSummaryProposal,
    hasSkillChoices,
    hasInstructionChoices,
    summaryRequested: true,
    skillsRequested: true,
    instructionsRequested: true,
  }
}

export function describeAiSkillRowForPreview(row, skillsCatalog) {
  if (!row) return ''
  const sk = (skillsCatalog || []).find((x) => Number(x.id) === Number(row.skill_id))
  const name = sk?.name || `Fähigkeit #${row.skill_id}`
  const int = formatExerciseSkillIntensityLabel(row.intensity)
  const from = formatSkillLevelSlug(row.required_level) || '—'
  const to = formatSkillLevelSlug(row.target_level) || '—'
  const prim = row.is_primary ? ' · Primär' : ''
  return `${name}: Intensität ${int}, Niveau ${from} → ${to}${prim}`
}

/** KI-Vorschau → bearbeitbarer Entwurf (Rich-Text-Felder). */
/** Rohes API-ai_suggestion oder bereits bearbeiteter Entwurf → Preview-Entwurf. */
export function ensureQuickCreateDraftFromAiSuggestion(
  aiSuggestion,
  { title = '', focusAreaId = '', sketchPlain = '' } = {},
) {
  if (!aiSuggestion || typeof aiSuggestion !== 'object') return null
  if (aiSuggestion.instructionFields) return aiSuggestion
  const preview = buildQuickCreateAiPreview(aiSuggestion, { sketchPlain })
  if (
    !preview.hasSummaryProposal &&
    !preview.hasInstructionChoices &&
    !preview.hasSkillChoices
  ) {
    return null
  }
  return aiPreviewToQuickCreateDraft(preview, { title, focusAreaId, sketchPlain })
}

export function aiPreviewToQuickCreateDraft(preview, { title, focusAreaId, sketchPlain }) {
  const sketchHtml = aiPlainTextToMinimalHtml(sketchPlain)
  const instructionFields = {
    goal: sketchHtml,
    execution: '',
    preparation: '',
    trainer_notes: '',
  }
  for (const c of preview?.instructionChoices || []) {
    if (c.field && c.include !== false && c.afterHtml) {
      instructionFields[c.field] = String(c.afterHtml)
    }
  }

  return {
    title: (title || '').trim(),
    focusAreaId: focusAreaId != null && focusAreaId !== '' ? String(focusAreaId) : '',
    summaryHtml:
      preview?.applySummary !== false && preview?.summaryAfterHtml ? String(preview.summaryAfterHtml) : '',
    instructionFields,
    skillChoices: (preview?.skillChoices || []).map((c) => ({ ...c })),
  }
}

/**
 * createExercise-Payload aus bearbeitetem Entwurf.
 * @throws {Error}
 */
export function buildQuickCreateExercisePayloadFromDraft(draft) {
  const title = (draft?.title || '').trim()
  if (title.length < 3) {
    throw new Error('Titel: mindestens 3 Zeichen.')
  }

  const fid = Number(draft?.focusAreaId)
  if (!Number.isFinite(fid) || fid < 1) {
    throw new Error('Fokusbereich ist erforderlich.')
  }

  const fields = draft?.instructionFields || {}
  let goal = (fields.goal || '').trim()
  let execution = (fields.execution || '').trim()
  const prep = (fields.preparation || '').trim() || null
  const trainerNotes = (fields.trainer_notes || '').trim() || null

  if (!stripHtmlToText(goal).trim() && !stripHtmlToText(execution).trim()) {
    throw new Error('Mindestens Ziel oder Durchführung ausfüllen.')
  }
  if (!stripHtmlToText(goal).trim()) goal = execution
  if (!stripHtmlToText(execution).trim()) execution = goal

  let summary = (draft?.summaryHtml || '').trim() || null
  if (summary && !stripHtmlToText(summary).trim()) summary = null

  const skills = (draft?.skillChoices || []).filter((c) => c.include).map((c) => c.after)

  return {
    title,
    summary,
    goal,
    execution,
    preparation: prep,
    trainer_notes: trainerNotes,
    visibility: 'private',
    status: 'draft',
    equipment: [],
    focus_areas_multi: [{ focus_area_id: fid, is_primary: true }],
    training_styles_multi: [],
    training_types_multi: [],
    target_groups_multi: [],
    age_groups: [],
    skills,
    club_id: null,
  }
}

/**
 * createExercise-Payload aus bestätigter Vorschau (Checkbox-Modus).
 * @throws {Error}
 */
export function buildQuickCreateExercisePayloadFromPreview(preview, { title, focusAreaId, sketchPlain }) {
  const sketchHtml = aiPlainTextToMinimalHtml(sketchPlain)
  const fieldMap = {}
  for (const c of preview?.instructionChoices || []) {
    if (c.include && c.afterHtml) fieldMap[c.field] = c.afterHtml
  }

  let goal = (fieldMap.goal || '').trim() || sketchHtml
  let execution = (fieldMap.execution || '').trim()
  const prep = (fieldMap.preparation || '').trim() || null
  const trainerNotes = (fieldMap.trainer_notes || '').trim() || null

  if (!stripHtmlToText(goal).trim() && !stripHtmlToText(execution).trim()) {
    throw new Error('Mindestens Ziel oder Durchführung muss übernommen werden.')
  }
  if (!stripHtmlToText(goal).trim()) goal = execution
  if (!stripHtmlToText(execution).trim()) execution = goal

  let summary = null
  if (preview?.applySummary && preview?.summaryAfterHtml) {
    summary = preview.summaryAfterHtml
  }

  const skills = (preview?.skillChoices || []).filter((c) => c.include).map((c) => c.after)

  const fid = Number(focusAreaId)
  if (!Number.isFinite(fid) || fid < 1) {
    throw new Error('Fokusbereich ist erforderlich.')
  }

  return {
    title: (title || '').trim(),
    summary,
    goal,
    execution,
    preparation: prep,
    trainer_notes: trainerNotes,
    visibility: 'private',
    status: 'draft',
    equipment: [],
    focus_areas_multi: [{ focus_area_id: fid, is_primary: true }],
    training_styles_multi: [],
    training_types_multi: [],
    target_groups_multi: [],
    age_groups: [],
    skills,
    club_id: null,
  }
}

/** @deprecated Direkt aus API — nutze Preview + buildQuickCreateExercisePayloadFromPreview */
export function buildQuickCreateExercisePayload({ title, focusAreaId, sketchPlain, apiRes }) {
  const preview = buildQuickCreateAiPreview(apiRes, { sketchPlain })
  return buildQuickCreateExercisePayloadFromPreview(preview, { title, focusAreaId, sketchPlain })
}