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

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

/** 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,
  }
}

/**
 * Baut createExercise-Payload aus suggestExerciseAi-Antwort.
 * @throws {Error} wenn Ziel/Durchführung nach KI leer wären
 */
export function buildQuickCreateExercisePayload({ title, focusAreaId, sketchPlain, apiRes }) {
  const sketchHtml = aiPlainTextToMinimalHtml(sketchPlain)
  const fields = apiRes?.instructions?.fields || {}

  let goal = (fields.goal || '').trim() || sketchHtml
  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('KI lieferte keine verwertbare Anleitung (Ziel/Durchführung leer).')
  }
  if (!stripHtmlToText(goal).trim()) goal = execution
  if (!stripHtmlToText(execution).trim()) execution = goal

  let summary = null
  if (apiRes?.summary?.text) {
    const sumHtml = aiPlainTextToMinimalHtml(apiRes.summary.text)
    if (sumHtml) summary = sumHtml
  }

  const skills = []
  if (Array.isArray(apiRes?.skills)) {
    for (const sug of apiRes.skills) {
      const row = normalizeAiSkillRowFromApi(sug)
      if (row) skills.push(row)
    }
  }

  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,
  }
}