feat(flyer-parsing): add flyer parsing module

- Added new FlyerParsingModule to the application
- Updated AppModule to import the new FlyerParsingModule
- Added new directory structure for flyer-parsing module

backend/src/app.module.ts

@@ -1,8 +1,9 @@
-import { Module, Controller, Get } from '@nestjs/common';
-import { WebScrapingModule } from './web-scraping-service/web-scraping.module';
-import { RecipesModule } from './recipes/recipes.module';
-import { DocumentServiceModule } from './document-service/document-service.module';
-import { ReceiptParsingModule } from './receipt-parsing/receipt-parsing.module';
+import { Module, Controller, Get } from '@nestjs/common';
+import { WebScrapingModule } from './web-scraping-service/web-scraping.module';
+import { RecipesModule } from './recipes/recipes.module';
+import { DocumentServiceModule } from './document-service/document-service.module';
+import { ReceiptParsingModule } from './receipt-parsing/receipt-parsing.module';
+import { FlyerParsingModule } from './flyer-parsing/flyer-parsing.module';
 
 @Controller('health')
 class HealthController {
@@ -15,10 +16,11 @@ class HealthController {
 @Module({
   imports: [
     DocumentServiceModule,
-    WebScrapingModule,
-    RecipesModule,
-    ReceiptParsingModule,
-  ],
+    WebScrapingModule,
+    RecipesModule,
+    ReceiptParsingModule,
+    FlyerParsingModule,
+  ],
   controllers: [HealthController],
 })
 export class AppModule {}

backend/src/flyer-parsing/dto/parse-flyer.dto.ts

@@ -0,0 +1,13 @@
+import { IsIn, IsOptional, IsString, MinLength } from 'class-validator';
+
+export class ParseFlyerDto {
+  @IsOptional()
+  @IsString()
+  @MinLength(20)
+  text?: string;
+
+  @IsOptional()
+  @IsString()
+  @IsIn(['willys'])
+  retailer?: 'willys';
+}

backend/src/flyer-parsing/flyer-parsing.controller.ts

@@ -0,0 +1,58 @@
+import {
+  BadRequestException,
+  Body,
+  Controller,
+  HttpCode,
+  Post,
+  UploadedFile,
+  UseInterceptors,
+} from '@nestjs/common';
+import { FileInterceptor } from '@nestjs/platform-express';
+import { memoryStorage } from 'multer';
+import { ParseFlyerDto } from './dto/parse-flyer.dto';
+import { FlyerParseResponse, FlyerParsingService } from './flyer-parsing.service';
+
+const ALLOWED_UPLOAD_MIMES = new Set([
+  'application/pdf',
+  'application/octet-stream',
+  'text/plain',
+]);
+
+@Controller('flyer')
+export class FlyerParsingController {
+  constructor(private readonly flyerParsingService: FlyerParsingService) {}
+
+  @Post('parse')
+  @HttpCode(200)
+  @UseInterceptors(
+    FileInterceptor('file', {
+      storage: memoryStorage(),
+      limits: { fileSize: 15 * 1024 * 1024 },
+      fileFilter: (_req, file, cb) => {
+        if (ALLOWED_UPLOAD_MIMES.has(file.mimetype)) {
+          cb(null, true);
+          return;
+        }
+        cb(
+          new BadRequestException('Otillåten filtyp för flyer-parser. Stöd: PDF eller textfil.'),
+          false,
+        );
+      },
+    }),
+  )
+  async parseFlyer(
+    @Body() body: ParseFlyerDto,
+    @UploadedFile() file?: Express.Multer.File,
+  ): Promise<FlyerParseResponse> {
+    if (!file && !body?.text?.trim()) {
+      throw new BadRequestException('Skicka antingen fil under "file" eller text i body.text.');
+    }
+
+    const text = body?.text?.trim();
+    return this.flyerParsingService.parseFlyer({
+      file,
+      text,
+      retailer: body?.retailer ?? 'willys',
+    });
+  }
+}

backend/src/flyer-parsing/flyer-parsing.module.ts

@@ -0,0 +1,9 @@
+import { Module } from '@nestjs/common';
+import { FlyerParsingController } from './flyer-parsing.controller';
+import { FlyerParsingService } from './flyer-parsing.service';
+
+@Module({
+  controllers: [FlyerParsingController],
+  providers: [FlyerParsingService],
+})
+export class FlyerParsingModule {}

backend/src/flyer-parsing/flyer-parsing.service.ts

@@ -0,0 +1,193 @@
+import { BadRequestException, Injectable, Logger } from '@nestjs/common';
+// eslint-disable-next-line @typescript-eslint/no-require-imports, @typescript-eslint/no-var-requires
+const pdfParse = require('pdf-parse') as (buffer: Buffer) => Promise<{ text: string }>;
+import { normalizeName } from '../common/utils/normalize-name';
+
+const CATEGORY_REGEX = /^(Fisk|Kott|Kött|Mejeri|Gronsaker|Grönsaker|Frukt|Dryck|Brod|Bröd|Pasta|Ris)\b/i;
+
+export type FlyerParseItem = {
+  rawName: string;
+  normalizedName: string;
+  category: string | null;
+  price: number | null;
+  priceUnit: string | null;
+  comparisonPrice: number | null;
+  comparisonUnit: string | null;
+  offerText: string | null;
+  confidence: number;
+  reasonCodes: string[];
+};
+
+export type FlyerParseResponse = {
+  retailer: 'willys';
+  parserVersion: 'v1';
+  items: FlyerParseItem[];
+  warnings: string[];
+};
+
+@Injectable()
+export class FlyerParsingService {
+  private readonly logger = new Logger(FlyerParsingService.name);
+
+  async parseFlyer(args: {
+    file?: Express.Multer.File;
+    text?: string;
+    retailer?: 'willys';
+  }): Promise<FlyerParseResponse> {
+    const retailer = args.retailer ?? 'willys';
+    const warnings: string[] = [];
+    const text = args.text?.trim() || (args.file ? await this.extractTextFromFile(args.file, warnings) : '');
+
+    if (!text) {
+      throw new BadRequestException('Ingen text kunde extraheras från underlaget.');
+    }
+
+    const items = this.parseWillysText(text);
+    if (items.length === 0) {
+      warnings.push('Inga produkter kunde tolkas. Kontrollera PDF-kvalitet eller textformat.');
+    }
+
+    return {
+      retailer,
+      parserVersion: 'v1',
+      items,
+      warnings,
+    };
+  }
+
+  private async extractTextFromFile(file: Express.Multer.File, warnings: string[]): Promise<string> {
+    const isPdf =
+      file.mimetype === 'application/pdf' ||
+      file.mimetype === 'application/octet-stream' ||
+      file.originalname?.toLowerCase().endsWith('.pdf');
+
+    if (!isPdf) {
+      throw new BadRequestException('Endast PDF stöds i detta steg för flyer-parsning.');
+    }
+
+    try {
+      const parsed = await pdfParse(file.buffer);
+      const text = parsed.text?.trim() ?? '';
+      if (text) return text;
+      warnings.push('PDF lästes men textinnehållet var tomt.');
+      return '';
+    } catch (err) {
+      this.logger.warn(`pdf-parse misslyckades för flyer: ${String(err)}`);
+      throw new BadRequestException('Kunde inte läsa PDF-underlaget.');
+    }
+  }
+
+  private parseWillysText(text: string): FlyerParseItem[] {
+    const lines = text
+      .split('\n')
+      .map((line) => line.replace(/\s+/g, ' ').trim())
+      .filter((line) => line.length > 1);
+
+    const items: FlyerParseItem[] = [];
+    let currentCategory: string | null = null;
+
+    for (const line of lines) {
+      const categoryMatch = line.match(CATEGORY_REGEX);
+      if (categoryMatch) {
+        currentCategory = this.normalizeCategory(categoryMatch[1]);
+        continue;
+      }
+
+      if (this.isIgnoredLine(line)) {
+        continue;
+      }
+
+      const parsed = this.parseProductLine(line, currentCategory);
+      if (parsed) {
+        items.push(parsed);
+      }
+    }
+
+    return this.deduplicate(items);
+  }
+
+  private parseProductLine(line: string, category: string | null): FlyerParseItem | null {
+    const segments = line.split(/[•|]/g).map((s) => s.trim()).filter(Boolean);
+    const source = segments.length > 0 ? segments.join(' ') : line;
+
+    const compareMatch = source.match(/j[aä]mf[oö]rpris\s*(\d{1,4}(?:[\.,:]\d{1,2})?)\s*kr\s*\/\s*([a-zåäö]+)/i);
+    const priceMatch = source.match(/(?:^|\s)(\d{1,4}(?:[\.,:]\d{1,2})?)\s*kr(?:\s*\/\s*([a-zåäö]+))?/i);
+    const offerMatch = source.match(/(max\s*\d+\s*(?:k[öo]p|f[öo]rp)\/?hush[åa]ll|l[aä]gsta\s*30-dgrspris\s*\d+[\.,:]?\d*\s*kr)/i);
+
+    const nameCandidate = this.extractNameCandidate(segments.length > 0 ? segments[0] : line);
+    if (!nameCandidate) {
+      return null;
+    }
+
+    const reasonCodes: string[] = [];
+    if (priceMatch) reasonCodes.push('price_found');
+    if (compareMatch) reasonCodes.push('comparison_price_found');
+    if (offerMatch) reasonCodes.push('offer_found');
+    if (segments.length > 1) reasonCodes.push('bullet_structured_line');
+
+    if (reasonCodes.length === 0) {
+      return null;
+    }
+
+    const confidence = Math.min(0.99, 0.45 + reasonCodes.length * 0.15);
+
+    return {
+      rawName: nameCandidate,
+      normalizedName: normalizeName(nameCandidate),
+      category,
+      price: priceMatch ? this.parseSvNumber(priceMatch[1]) : null,
+      priceUnit: priceMatch?.[2]?.toLowerCase() ?? null,
+      comparisonPrice: compareMatch ? this.parseSvNumber(compareMatch[1]) : null,
+      comparisonUnit: compareMatch?.[2]?.toLowerCase() ?? null,
+      offerText: offerMatch?.[1] ?? null,
+      confidence,
+      reasonCodes,
+    };
+  }
+
+  private extractNameCandidate(raw: string): string | null {
+    const cleaned = raw
+      .replace(/j[aä]mf[oö]rpris.*$/i, ' ')
+      .replace(/\b\d{1,4}(?:[\.,:]\d{1,2})?\s*kr(?:\s*\/\s*[a-zåäö]+)?\b/gi, ' ')
+      .replace(/\b(max\s*\d+\s*(?:k[öo]p|f[öo]rp)\/?hush[åa]ll|l[aä]gsta\s*30-dgrspris.*)$/i, ' ')
+      .replace(/\s+/g, ' ')
+      .trim();
+
+    if (cleaned.length < 2) return null;
+    if (!/[a-zåäö]/i.test(cleaned)) return null;
+    return cleaned;
+  }
+
+  private normalizeCategory(value: string): string {
+    const normalized = value
+      .toLowerCase()
+      .replace('kott', 'kött')
+      .replace('gronsaker', 'grönsaker')
+      .replace('brod', 'bröd');
+    return normalized.charAt(0).toUpperCase() + normalized.slice(1);
+  }
+
+  private parseSvNumber(value: string): number {
+    return Number.parseFloat(value.replace(':', '.').replace(',', '.'));
+  }
+
+  private isIgnoredLine(line: string): boolean {
+    const normalized = line.trim().toLowerCase();
+    if (normalized.length < 3) return true;
+    if (/^(willys|vecka|erbjudande|g[aä]ller|reservation)/i.test(normalized)) return true;
+    if (/^\d+\s*\/\s*\d+/.test(normalized)) return true;
+    return false;
+  }
+
+  private deduplicate(items: FlyerParseItem[]): FlyerParseItem[] {
+    const seen = new Set<string>();
+    const unique: FlyerParseItem[] = [];
+    for (const item of items) {
+      const key = `${item.normalizedName}|${item.price ?? ''}|${item.comparisonPrice ?? ''}|${item.category ?? ''}`;
+      if (seen.has(key)) continue;
+      seen.add(key);
+      unique.push(item);
+    }
+    return unique;
+  }
+}