'use strict';
const { deepClone, htmlToText, escapeHtml } = require('./util');
const { sanitizeHtml } = require('./sanitize');
const {
  TEXTBLOCK_LEVELS,
  TEXTBLOCK_POSITIONS,
  normalizeTextBlock,
  normalizeCodeBlock,
  normalizeTableBlock,
} = require('./schema');

const DEFAULT_CAPTURE_TITLES = {
  fullscreen: 'Screen capture',
  window: 'Window capture',
  region: 'Region capture',
};

const AI_LEVEL_ALIASES = new Map([
  ['note', 'info'],
  ['info', 'info'],
  ['tip', 'success'],
  ['success', 'success'],
  ['warning', 'warn'],
  ['warn', 'warn'],
  ['important', 'error'],
  ['error', 'error'],
]);

const GENERIC_OCR_PHRASES = new Set([
  'button',
  'click',
  'double click',
  'menu',
  'item',
  'field',
  'text field',
  'search',
  'submit',
  'cancel',
  'ok',
  'open',
  'select',
  'enter',
  'type',
]);

function normalizeWhitespace(text) {
  return String(text == null ? '' : text)
    .replace(/\s+/g, ' ')
    .trim();
}

function titleCaseWord(word) {
  if (!word) return word;
  if (/^[A-Z0-9]{2,}$/.test(word)) return word;
  if (/^\d+$/.test(word)) return word;
  return word[0].toUpperCase() + word.slice(1).toLowerCase();
}

function displayText(text) {
  const clean = normalizeWhitespace(text)
    .replace(/^[\s"'`([{<]+|[\s"'`)}\]>.,;:!?]+$/g, '')
    .trim();
  if (!clean) return '';
  if (clean === clean.toUpperCase()) {
    return clean.split(/\s+/).map(titleCaseWord).join(' ');
  }
  return clean.replace(/\s+/g, ' ');
}

function candidateWords(text) {
  const clean = normalizeWhitespace(text);
  if (!clean) return [];
  return clean.split(/\s+/).filter(Boolean);
}

function scoreCandidate(text, { source = 'ocr' } = {}) {
  const clean = displayText(text);
  if (!clean) return -Infinity;
  const words = candidateWords(clean);
  if (!words.length) return -Infinity;
  let score = 0;
  score += source === 'element' ? 110 : source === 'window' ? 95 : source === 'app' ? 80 : 100;
  score += Math.min(words.length, 6) * 12;
  score -= Math.max(0, words.length - 6) * 10;
  score -= Math.max(0, clean.length - 56) * 0.6;
  if (GENERIC_OCR_PHRASES.has(clean.toLowerCase())) score -= 50;
  if (clean.length <= 24) score += 10;
  if (/^(click|open|enter|type|choose|select|save|cancel|confirm)\b/i.test(clean)) score += 8;
  if (/^[\p{P}\p{S}0-9]+$/u.test(clean)) score -= 100;
  return score;
}

function pickBestOcrPhrase(ocrText) {
  const text = normalizeWhitespace(ocrText);
  if (!text) return '';
  const parts = text
    .split(/\n+/)
    .map((line) => displayText(line))
    .filter(Boolean)
    .filter((line) => !GENERIC_OCR_PHRASES.has(line.toLowerCase()));
  if (!parts.length) return '';
  let best = '';
  let bestScore = -Infinity;
  for (const part of parts) {
    const score = scoreCandidate(part, { source: 'ocr' });
    if (score > bestScore) {
      best = part;
      bestScore = score;
    }
  }
  return best;
}

function isShortUiLabel(text) {
  const words = candidateWords(text);
  return words.length > 0 && words.length <= 2 && text.length <= 24;
}

function buildCaptureTitle({ mode = 'fullscreen', metadata = {}, ocrText = '' } = {}) {
  const candidates = [];
  if (metadata.elementLabel) candidates.push({ text: metadata.elementLabel, source: 'element' });
  if (metadata.windowTitle) candidates.push({ text: metadata.windowTitle, source: 'window' });
  if (metadata.appName && metadata.appName !== metadata.windowTitle) {
    candidates.push({ text: metadata.appName, source: 'app' });
  }
  const ocrPhrase = pickBestOcrPhrase(ocrText);
  if (ocrPhrase) candidates.push({ text: ocrPhrase, source: 'ocr' });

  let winner = null;
  let winnerScore = -Infinity;
  for (const candidate of candidates) {
    const score = scoreCandidate(candidate.text, { source: candidate.source });
    if (score > winnerScore) {
      winner = candidate;
      winnerScore = score;
    }
  }

  const cleanedWinner = winner ? displayText(winner.text) : '';
  if (!cleanedWinner) return DEFAULT_CAPTURE_TITLES[mode] || 'Capture';

  if (winner.source === 'window' || winner.source === 'app') {
    return `Open ${cleanedWinner}`;
  }
  if (winner.source === 'element') {
    return isShortUiLabel(cleanedWinner) ? `Click ${cleanedWinner}` : cleanedWinner;
  }
  if (winner.source === 'ocr') {
    return isShortUiLabel(cleanedWinner) ? `Click ${cleanedWinner}` : cleanedWinner;
  }
  return cleanedWinner;
}

function plainTextToHtml(text) {
  const trimmed = normalizeWhitespace(text);
  if (!trimmed) return '';
  return trimmed
    .split(/\n{2,}/)
    .map((para) => `<p>${escapeHtml(para).replace(/\n/g, '<br>')}</p>`)
    .join('');
}

function normalizeOllamaHost(host) {
  const raw = normalizeWhitespace(host);
  if (!raw) return '';
  if (/^https?:\/\//i.test(raw)) return raw.replace(/\/+$/, '');
  return `http://${raw.replace(/\/+$/, '')}`;
}

function normalizeAiLevel(level) {
  const key = normalizeWhitespace(level).toLowerCase();
  return AI_LEVEL_ALIASES.get(key) || (TEXTBLOCK_LEVELS.includes(key) ? key : 'info');
}

function normalizeAiPosition(position) {
  const key = normalizeWhitespace(position).toLowerCase();
  return TEXTBLOCK_POSITIONS.includes(key) ? key : 'after-description';
}

function normalizeAiBlock(block) {
  if (!block || typeof block !== 'object') return null;
  const kind = normalizeWhitespace(block.kind).toLowerCase();
  if (kind === 'text') {
    const normalized = normalizeTextBlock({
      id: block.id,
      order: Number.isFinite(block.order) ? block.order : null,
      position: normalizeAiPosition(block.position),
      level: normalizeAiLevel(block.level),
      title: displayText(block.title),
      descriptionHtml: plainTextToHtml(block.body ?? block.description ?? block.text ?? ''),
    }, Number.isFinite(block.order) ? block.order : null);
    return { ...normalized, kind: 'text' };
  }
  if (kind === 'code') {
    return {
      ...normalizeCodeBlock({
        id: block.id,
        order: Number.isFinite(block.order) ? block.order : null,
        language: displayText(block.language).toLowerCase(),
        code: String(block.code ?? ''),
      }, Number.isFinite(block.order) ? block.order : null),
      kind: 'code',
    };
  }
  if (kind === 'table') {
    const rows = Array.isArray(block.rows)
      ? block.rows.map((row) => (Array.isArray(row) ? row.map((cell) => displayText(cell)) : []))
      : [];
    return {
      ...normalizeTableBlock({
        id: block.id,
        order: Number.isFinite(block.order) ? block.order : null,
        rows,
      }, Number.isFinite(block.order) ? block.order : null),
      kind: 'table',
    };
  }
  return null;
}

function normalizeAiPatch(raw) {
  let data = raw;
  if (typeof raw === 'string') {
    const trimmed = raw.trim().replace(/^```(?:json)?\s*|\s*```$/g, '');
    const start = trimmed.indexOf('{');
    const end = trimmed.lastIndexOf('}');
    const jsonText = start >= 0 && end > start ? trimmed.slice(start, end + 1) : trimmed;
    data = JSON.parse(jsonText);
  }
  if (!data || typeof data !== 'object' || Array.isArray(data)) {
    throw new Error('AI response must be a JSON object');
  }
  const out = {
    title: displayText(data.title),
    descriptionHtml: plainTextToHtml(data.description ?? data.descriptionText ?? ''),
    blocks: Array.isArray(data.blocks)
      ? data.blocks.map((block) => normalizeAiBlock(block)).filter(Boolean)
      : [],
  };
  return out;
}

function summarizeBlocks(step = {}) {
  const parts = [];
  for (const block of step.textBlocks || []) {
    const body = htmlToText(block.descriptionHtml || '');
    parts.push(`- Text (${block.level || 'info'}, ${block.position || 'after-description'}): ${block.title || ''}${body ? ` — ${body}` : ''}`.trim());
  }
  for (const block of step.codeBlocks || []) {
    const code = String(block.code || '').trim();
    parts.push(`- Code (${block.language || 'plain'}):\n${code || '(empty)'}`);
  }
  for (const block of step.tableBlocks || []) {
    const rows = Array.isArray(block.rows) ? block.rows.length : 0;
    const cols = rows > 0 && Array.isArray(block.rows[0]) ? block.rows[0].length : 0;
    parts.push(`- Table (${rows}x${cols})`);
  }
  return parts.length ? parts.join('\n') : '(none)';
}

function summarizeStepForAi(step = {}) {
  return [
    `Step title: ${step.title || '(empty)'}`,
    `Step description: ${htmlToText(step.descriptionHtml || '') || '(empty)'}`,
    `Step status: ${step.status || 'todo'}`,
    `Blocks:\n${summarizeBlocks(step)}`,
  ].join('\n');
}

function summarizeGuideForAi(guide = {}) {
  return [
    `Guide title: ${guide.title || '(untitled)'}`,
    `Guide description: ${htmlToText(guide.descriptionHtml || '') || '(empty)'}`,
  ].join('\n');
}

function buildAiPrompt({
  target = 'all',
  guide = null,
  step = null,
  captureContext = null,
  block = null,
} = {}) {
  const targetText = {
    title: 'rewrite only the step title',
    description: 'rewrite only the step description',
    block: 'rewrite only one block',
    all: 'rewrite the step title, description, and any useful blocks',
  }[target] || 'rewrite the step';

  const allowedBlockNote = [
    'Use block.kind = "text" with level in [info, warn, error, success] for note / warning / important / tip blocks.',
    'Use block.kind = "code" for code snippets.',
    'Use block.kind = "table" for tables, with rows as arrays of strings.',
    'Use block.position values from [before-title, after-title, before-image, after-image, before-description, after-description].',
  ].join(' ');

  const prompt = [
    'You write concise, human-sounding step-by-step documentation for an offline desktop app.',
    'Return JSON only. No markdown fences, no commentary, no extra keys outside the schema below.',
    'Schema:',
    '{',
    '  "title": string,',
    '  "description": string,',
    '  "blocks": [{',
    '    "kind": "text" | "code" | "table",',
    '    "position"?: "before-title" | "after-title" | "before-image" | "after-image" | "before-description" | "after-description",',
    '    "level"?: "info" | "warn" | "error" | "success",',
    '    "title"?: string,',
    '    "body"?: string,',
    '    "language"?: string,',
    '    "code"?: string,',
    '    "rows"?: string[][]',
    '  }]',
    '}',
    '',
    `Target: ${targetText}.`,
    allowedBlockNote,
    '',
    guide ? summarizeGuideForAi(guide) : 'Guide: (not provided)',
    '',
    step ? summarizeStepForAi(step) : 'Step: (not provided)',
    '',
    captureContext ? [
      `Active window title: ${captureContext.windowTitle || '(unknown)'}`,
      `Active app: ${captureContext.appName || '(unknown)'}`,
      `OCR text near click: ${captureContext.ocrText || '(none)'}`,
      `Capture mode: ${captureContext.mode || '(unknown)'}`,
    ].join('\n') : 'Capture context: (not provided)',
    '',
    block ? `Target block:\n${JSON.stringify(block, null, 2)}` : 'Target block: (not provided)',
    '',
    'Rules:',
    '- Keep the wording natural and specific.',
    '- Prefer short titles.',
    '- Only return blocks that add value.',
    '- Do not invent details that are not supported by the capture context.',
    '- If the target is one block, only rewrite that block.',
  ].join('\n');

  return {
    systemPrompt: 'You are a documentation assistant that only emits JSON.',
    prompt,
  };
}

function applyAiPatchToStep(step, patch, { target = 'all', blockId = null } = {}) {
  const next = deepClone(step);
  if ((target === 'all' || target === 'title') && patch.title) {
    next.title = displayText(patch.title);
  }
  if ((target === 'all' || target === 'description') && patch.descriptionHtml) {
    next.descriptionHtml = sanitizeHtml(patch.descriptionHtml);
  }

  if (target === 'all' && Array.isArray(patch.blocks) && patch.blocks.length) {
    const textBlocks = [];
    const codeBlocks = [];
    const tableBlocks = [];
    let nextOrder = 1;
    for (const block of patch.blocks) {
      const clone = deepClone(block);
      clone.order = nextOrder++;
      if (clone.kind === 'text') textBlocks.push(clone);
      else if (clone.kind === 'code') codeBlocks.push(clone);
      else if (clone.kind === 'table') tableBlocks.push(clone);
    }
    next.textBlocks = textBlocks;
    next.codeBlocks = codeBlocks;
    next.tableBlocks = tableBlocks;
  } else if (target === 'block' && blockId && Array.isArray(patch.blocks) && patch.blocks.length) {
    const replacement = patch.blocks[0];
    const textBlock = (next.textBlocks || []).find((block) => block.id === blockId);
    const codeBlock = (next.codeBlocks || []).find((block) => block.id === blockId);
    const tableBlock = (next.tableBlocks || []).find((block) => block.id === blockId);
    if (textBlock && replacement.kind === 'text') {
      if (replacement.position) textBlock.position = replacement.position;
      if (replacement.level) textBlock.level = replacement.level;
      if (replacement.title) textBlock.title = replacement.title;
      if (replacement.descriptionHtml) textBlock.descriptionHtml = sanitizeHtml(replacement.descriptionHtml);
    } else if (codeBlock && replacement.kind === 'code') {
      if (replacement.language) codeBlock.language = replacement.language;
      if (replacement.code) codeBlock.code = replacement.code;
    } else if (tableBlock && replacement.kind === 'table') {
      if (replacement.rows) tableBlock.rows = replacement.rows;
    }
  }
  if (!next.image) {
    const hasBody = Boolean(
      next.title ||
      htmlToText(next.descriptionHtml || '') ||
      (next.textBlocks || []).length ||
      (next.codeBlocks || []).length ||
      (next.tableBlocks || []).length,
    );
    if (hasBody) next.kind = 'content';
  }
  return next;
}

module.exports = {
  DEFAULT_CAPTURE_TITLES,
  buildCaptureTitle,
  plainTextToHtml,
  normalizeOllamaHost,
  normalizeAiPatch,
  buildAiPrompt,
  applyAiPatchToStep,
  summarizeStepForAi,
  summarizeGuideForAi,
  displayText,
  normalizeWhitespace,
  scoreCandidate,
  pickBestOcrPhrase,
};