/**
 * Invoice extraction using Qwen3-VL-8B Vision (Direct)
 *
 * Qwen3-VL 8B is a capable vision-language model that fits in 15GB VRAM:
 *   - Q4_K_M quantization (~5GB)
 *   - Good balance of speed and accuracy
 *
 * Pipeline: PDF → Images → Qwen3-VL → JSON
 */
import { tap, expect } from '@git.zone/tstest/tapbundle';
import * as fs from 'fs';
import * as path from 'path';
import { execSync } from 'child_process';
import * as os from 'os';
import { ensureQwen3Vl } from './helpers/docker.js';

const OLLAMA_URL = 'http://localhost:11434';
const VISION_MODEL = 'qwen3-vl:8b';

interface IInvoice {
  invoice_number: string;
  invoice_date: string;
  vendor_name: string;
  currency: string;
  net_amount: number;
  vat_amount: number;
  total_amount: number;
}

/**
 * Convert PDF to PNG images using ImageMagick
 */
function convertPdfToImages(pdfPath: string): string[] {
  const tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'pdf-convert-'));
  const outputPattern = path.join(tempDir, 'page-%d.png');

  try {
    // 150 DPI is sufficient for invoice extraction, reduces context size
    execSync(
      `convert -density 150 -quality 90 "${pdfPath}" -background white -alpha remove "${outputPattern}"`,
      { stdio: 'pipe' }
    );

    const files = fs.readdirSync(tempDir).filter((f) => f.endsWith('.png')).sort();
    const images: string[] = [];

    for (const file of files) {
      const imagePath = path.join(tempDir, file);
      const imageData = fs.readFileSync(imagePath);
      images.push(imageData.toString('base64'));
    }

    return images;
  } finally {
    fs.rmSync(tempDir, { recursive: true, force: true });
  }
}

/**
 * Single extraction attempt
 */
async function tryExtractOnce(images: string[], prompt: string): Promise<string> {
  const response = await fetch(`${OLLAMA_URL}/api/chat`, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify({
      model: VISION_MODEL,
      messages: [
        {
          role: 'user',
          content: prompt,
          images: images,
        },
      ],
      stream: true,
      options: {
        num_predict: 1024,
        temperature: 0.1, // Slight randomness helps avoid stuck states
      },
    }),
  });

  if (!response.ok) {
    throw new Error(`Ollama API error: ${response.status}`);
  }

  const reader = response.body?.getReader();
  if (!reader) {
    throw new Error('No response body');
  }

  const decoder = new TextDecoder();
  let fullText = '';

  while (true) {
    const { done, value } = await reader.read();
    if (done) break;

    const chunk = decoder.decode(value, { stream: true });
    const lines = chunk.split('\n').filter((l) => l.trim());

    for (const line of lines) {
      try {
        const json = JSON.parse(line);
        if (json.message?.content) {
          fullText += json.message.content;
        }
      } catch {
        // Skip invalid JSON lines
      }
    }
  }

  return fullText;
}

/**
 * Extract invoice data directly from images using Qwen3-VL Vision
 * Includes retry logic for empty responses
 */
async function extractInvoiceFromImages(images: string[]): Promise<IInvoice> {
  console.log(`    [Vision] Processing ${images.length} page(s) with Qwen3-VL`);

  // JSON schema for structured output - force the model to output valid JSON
  const invoiceSchema = {
    type: 'object',
    properties: {
      invoice_number: { type: 'string' },
      invoice_date: { type: 'string' },
      vendor_name: { type: 'string' },
      currency: { type: 'string' },
      net_amount: { type: 'number' },
      vat_amount: { type: 'number' },
      total_amount: { type: 'number' },
    },
    required: ['invoice_number', 'invoice_date', 'vendor_name', 'currency', 'net_amount', 'vat_amount', 'total_amount'],
  };

  // Simple, direct prompt - don't overthink, just read the labeled fields
  const prompt = `Extract invoice data from this image. Return JSON only.

Find these fields:
- invoice_number: The invoice/document number
- invoice_date: Date in YYYY-MM-DD format
- vendor_name: Company issuing the invoice
- currency: EUR, USD, or GBP
- net_amount: Amount before tax
- vat_amount: Tax/VAT amount
- total_amount: Final total amount

Return: {"invoice_number":"...", "invoice_date":"YYYY-MM-DD", "vendor_name":"...", "currency":"EUR", "net_amount":0.00, "vat_amount":0.00, "total_amount":0.00}`;

  // Retry logic for empty responses (model sometimes returns nothing)
  const MAX_RETRIES = 3;
  let fullText = '';

  for (let attempt = 1; attempt <= MAX_RETRIES; attempt++) {
    fullText = await tryExtractOnce(images, prompt);

    if (fullText.trim().length > 0) {
      console.log(`    [Attempt ${attempt}] Got ${fullText.length} chars`);
      break;
    }

    console.log(`    [Attempt ${attempt}] Empty response, retrying...`);
    // Small delay before retry
    await new Promise((r) => setTimeout(r, 1000));
  }

  if (fullText.trim().length === 0) {
    throw new Error(`Model returned empty response after ${MAX_RETRIES} attempts`);
  }

  // Parse JSON response
  let jsonStr = fullText.trim();

  if (jsonStr.startsWith('```json')) jsonStr = jsonStr.slice(7);
  else if (jsonStr.startsWith('```')) jsonStr = jsonStr.slice(3);
  if (jsonStr.endsWith('```')) jsonStr = jsonStr.slice(0, -3);
  jsonStr = jsonStr.trim();

  const startIdx = jsonStr.indexOf('{');
  const endIdx = jsonStr.lastIndexOf('}') + 1;

  if (startIdx < 0 || endIdx <= startIdx) {
    throw new Error(`No JSON found in: ${fullText.substring(0, 500)}`);
  }

  const extractedJson = jsonStr.substring(startIdx, endIdx);
  console.log(`    [Debug] Extracted JSON: ${extractedJson.substring(0, 200)}...`);

  let parsed;
  try {
    parsed = JSON.parse(extractedJson);
  } catch (e) {
    throw new Error(`Invalid JSON: ${extractedJson.substring(0, 500)}`);
  }

  return {
    invoice_number: parsed.invoice_number || null,
    invoice_date: parsed.invoice_date || null,
    vendor_name: parsed.vendor_name || null,
    currency: parsed.currency || 'EUR',
    net_amount: parseFloat(parsed.net_amount) || 0,
    vat_amount: parseFloat(parsed.vat_amount) || 0,
    total_amount: parseFloat(parsed.total_amount) || 0,
  };
}

/**
 * Normalize date to YYYY-MM-DD
 */
function normalizeDate(dateStr: string | null): string {
  if (!dateStr) return '';
  if (/^\d{4}-\d{2}-\d{2}$/.test(dateStr)) return dateStr;

  const monthMap: Record<string, string> = {
    JAN: '01', FEB: '02', MAR: '03', APR: '04', MAY: '05', JUN: '06',
    JUL: '07', AUG: '08', SEP: '09', OCT: '10', NOV: '11', DEC: '12',
  };

  let match = dateStr.match(/^(\d{1,2})-([A-Z]{3})-(\d{4})$/i);
  if (match) {
    return `${match[3]}-${monthMap[match[2].toUpperCase()] || '01'}-${match[1].padStart(2, '0')}`;
  }

  match = dateStr.match(/^(\d{1,2})[\/.](\d{1,2})[\/.](\d{4})$/);
  if (match) {
    return `${match[3]}-${match[2].padStart(2, '0')}-${match[1].padStart(2, '0')}`;
  }

  return dateStr;
}

/**
 * Compare extracted vs expected
 */
function compareInvoice(extracted: IInvoice, expected: IInvoice): { match: boolean; errors: string[] } {
  const errors: string[] = [];

  const extNum = extracted.invoice_number?.replace(/\s/g, '').toLowerCase() || '';
  const expNum = expected.invoice_number?.replace(/\s/g, '').toLowerCase() || '';
  if (extNum !== expNum) {
    errors.push(`invoice_number: expected "${expected.invoice_number}", got "${extracted.invoice_number}"`);
  }

  if (normalizeDate(extracted.invoice_date) !== normalizeDate(expected.invoice_date)) {
    errors.push(`invoice_date: expected "${expected.invoice_date}", got "${extracted.invoice_date}"`);
  }

  if (Math.abs(extracted.total_amount - expected.total_amount) > 0.02) {
    errors.push(`total_amount: expected ${expected.total_amount}, got ${extracted.total_amount}`);
  }

  if (extracted.currency?.toUpperCase() !== expected.currency?.toUpperCase()) {
    errors.push(`currency: expected "${expected.currency}", got "${extracted.currency}"`);
  }

  return { match: errors.length === 0, errors };
}

/**
 * Find test cases
 */
function findTestCases(): Array<{ name: string; pdfPath: string; jsonPath: string }> {
  const testDir = path.join(process.cwd(), '.nogit/invoices');
  if (!fs.existsSync(testDir)) return [];

  const files = fs.readdirSync(testDir);
  const testCases: Array<{ name: string; pdfPath: string; jsonPath: string }> = [];

  for (const pdf of files.filter((f) => f.endsWith('.pdf'))) {
    const baseName = pdf.replace('.pdf', '');
    const jsonFile = `${baseName}.json`;
    if (files.includes(jsonFile)) {
      testCases.push({
        name: baseName,
        pdfPath: path.join(testDir, pdf),
        jsonPath: path.join(testDir, jsonFile),
      });
    }
  }

  return testCases.sort((a, b) => a.name.localeCompare(b.name));
}

// Tests

tap.test('setup: ensure Qwen3-VL is running', async () => {
  console.log('\n[Setup] Checking Qwen3-VL 8B (~5GB)...\n');
  const ok = await ensureQwen3Vl();
  expect(ok).toBeTrue();
  console.log('\n[Setup] Ready!\n');
});

const testCases = findTestCases();
console.log(`\nFound ${testCases.length} invoice test cases (Qwen3-VL Vision)\n`);

let passedCount = 0;
let failedCount = 0;
const times: number[] = [];

for (const testCase of testCases) {
  tap.test(`should extract invoice: ${testCase.name}`, async () => {
    const expected: IInvoice = JSON.parse(fs.readFileSync(testCase.jsonPath, 'utf-8'));
    console.log(`\n=== ${testCase.name} ===`);
    console.log(`Expected: ${expected.invoice_number} | ${expected.invoice_date} | ${expected.total_amount} ${expected.currency}`);

    const start = Date.now();
    const images = convertPdfToImages(testCase.pdfPath);
    console.log(`  Pages: ${images.length}`);

    const extracted = await extractInvoiceFromImages(images);
    console.log(`  Extracted: ${extracted.invoice_number} | ${extracted.invoice_date} | ${extracted.total_amount} ${extracted.currency}`);
    const elapsed = Date.now() - start;
    times.push(elapsed);

    const result = compareInvoice(extracted, expected);

    if (result.match) {
      passedCount++;
      console.log(`  Result: MATCH (${(elapsed / 1000).toFixed(1)}s)`);
    } else {
      failedCount++;
      console.log(`  Result: MISMATCH (${(elapsed / 1000).toFixed(1)}s)`);
      result.errors.forEach((e) => console.log(`    - ${e}`));
    }

    expect(result.match).toBeTrue();
  });
}

tap.test('summary', async () => {
  const total = testCases.length;
  const accuracy = total > 0 ? (passedCount / total) * 100 : 0;
  const totalTime = times.reduce((a, b) => a + b, 0) / 1000;
  const avgTime = times.length > 0 ? totalTime / times.length : 0;

  console.log(`\n======================================================`);
  console.log(`   Invoice Extraction Summary (Qwen3-VL Vision)`);
  console.log(`======================================================`);
  console.log(`  Method:    Qwen3-VL 8B (Direct Vision)`);
  console.log(`  Passed:    ${passedCount}/${total}`);
  console.log(`  Failed:    ${failedCount}/${total}`);
  console.log(`  Accuracy:  ${accuracy.toFixed(1)}%`);
  console.log(`------------------------------------------------------`);
  console.log(`  Total time:   ${totalTime.toFixed(1)}s`);
  console.log(`  Avg per inv:  ${avgTime.toFixed(1)}s`);
  console.log(`======================================================\n`);
});

export default tap.start();