chore(infra): add AI flyer parsing configuration and retry logic

- Add FLYER_AI_TIMEOUT_MS and FLYER_AI_RETRIES environment variables
- Configure timeout and retry settings in compose.yml
- Update AiFlyerParserService with configurable timeout and retry logic
- Add text window reduction strategy for retry attempts
- Update documentation in TEKNISK_BESKRIVNING.md
- Fix ESLint configuration in app.security.spec.ts

backend/src/flyer-import/services/ai-flyer-parser.service.ts

@@ -21,7 +21,8 @@ export interface AiFlyerParseResult {
 @Injectable()
 export class AiFlyerParserService {
   private readonly logger = new Logger(AiFlyerParserService.name);
-  private readonly timeoutMs = 15_000;
+  private readonly timeoutMs: number;
+  private readonly maxRetries: number;
   private mistral: any;
   private apiKey: string;
 
@@ -30,6 +31,9 @@ export class AiFlyerParserService {
     if (!this.apiKey) {
       throw new Error('MISTRAL_API_KEY environment variable not set');
     }
+
+    this.timeoutMs = this.readPositiveIntEnv('FLYER_AI_TIMEOUT_MS', 30_000);
+    this.maxRetries = this.readPositiveIntEnv('FLYER_AI_RETRIES', 2);
   }
 
   private async getClient(): Promise<any> {
@@ -50,38 +54,58 @@ export class AiFlyerParserService {
       throw new BadRequestException('Flyer-texten är tom. Kan inte fortsätta.');
     }
 
-    const prompt = this.buildPrompt(text);
-
     try {
-      this.logger.debug('Sending request to Mistral Tiny');
-
       const client = await this.getClient();
-      const response = await this.withTimeout<any>(
-        client.chat({
-        model: 'mistral-tiny',
-        messages: [{ role: 'user', content: prompt }],
-        temperature: 0.1,
-        }),
-        this.timeoutMs,
-        'Mistral-anrop timeout',
-      );
+      const textWindows = [5000, 3000, 2000];
+      const attempts = Math.max(1, Math.min(this.maxRetries + 1, textWindows.length));
+      let lastError: unknown = null;
 
-      const content = response.choices?.[0]?.message?.content;
-      if (!content) {
-        throw new BadRequestException('Tomt svar från AI-modellen.');
+      for (let i = 0; i < attempts; i++) {
+        const window = textWindows[i];
+        const prompt = this.buildPrompt(text, window);
+
+        try {
+          this.logger.debug(
+            `Sending request to Mistral Tiny (attempt ${i + 1}/${attempts}, timeout=${this.timeoutMs}ms, textWindow=${window})`,
+          );
+
+          const response = await this.withTimeout<any>(
+            client.chat({
+              model: 'mistral-tiny',
+              messages: [{ role: 'user', content: prompt }],
+              temperature: 0.1,
+            }),
+            this.timeoutMs,
+            'Mistral-anrop timeout',
+          );
+
+          const content = response.choices?.[0]?.message?.content;
+          if (!content) {
+            throw new BadRequestException('Tomt svar från AI-modellen.');
+          }
+
+          this.logger.debug(`Mistral response length: ${content.length} chars`);
+
+          const jsonString = this.sanitizeJsonResponse(content);
+          const items = JSON.parse(jsonString) as Array<Record<string, unknown>>;
+
+          if (!Array.isArray(items)) {
+            throw new BadRequestException('AI returnerade inte en JSON-array.');
+          }
+
+          return items.map((item, idx) => this.normalizeAiItem(item, idx));
+        } catch (attemptErr) {
+          lastError = attemptErr;
+          if (!this.isRetryableError(attemptErr) || i === attempts - 1) {
+            throw attemptErr;
+          }
+          this.logger.warn(
+            `Mistral attempt ${i + 1} failed (${this.toErrorMessage(attemptErr)}). Retrying with shorter text window.`,
+          );
+        }
       }
 
-      this.logger.debug(`Mistral response length: ${content.length} chars`);
-
-      // Rensa och parse JSON
-      const jsonString = this.sanitizeJsonResponse(content);
-      const items = JSON.parse(jsonString) as Array<Record<string, unknown>>;
-
-      if (!Array.isArray(items)) {
-        throw new BadRequestException('AI returnerade inte en JSON-array.');
-      }
-
-      return items.map((item, idx) => this.normalizeAiItem(item, idx));
+      throw lastError instanceof Error ? lastError : new ServiceUnavailableException('AI-anrop misslyckades');
     } catch (err) {
       if (err instanceof SyntaxError) {
         this.logger.error(`JSON parse error: ${String(err)}`);
@@ -121,9 +145,8 @@ export class AiFlyerParserService {
   /**
    * Bygger systemprompten för Mistral.
    */
-  private buildPrompt(text: string): string {
-    // Trunkera långt text för att spara tokens
-    const truncatedText = text.length > 5000 ? text.substring(0, 5000) : text;
+  private buildPrompt(text: string, maxTextLength: number): string {
+    const truncatedText = text.length > maxTextLength ? text.substring(0, maxTextLength) : text;
 
     return `Du är en expert på att tolka svenska matvaruflyers (t.ex. från Willys, Coop, ICA).
 
@@ -231,4 +254,32 @@ Exempel på utdata:
       .replace(/\s+/g, ' ')
       .trim();
   }
+
+  private readPositiveIntEnv(key: string, fallback: number): number {
+    const raw = process.env[key];
+    if (!raw) return fallback;
+    const parsed = Number.parseInt(raw, 10);
+    if (!Number.isFinite(parsed) || parsed <= 0) {
+      this.logger.warn(`Invalid ${key} value: "${raw}". Falling back to ${fallback}.`);
+      return fallback;
+    }
+    return parsed;
+  }
+
+  private isRetryableError(err: unknown): boolean {
+    if (err instanceof ServiceUnavailableException) return true;
+    const message = this.toErrorMessage(err).toLowerCase();
+    return (
+      message.includes('timeout') ||
+      message.includes('timed out') ||
+      message.includes('rate limit') ||
+      message.includes('econnreset') ||
+      message.includes('socket hang up')
+    );
+  }
+
+  private toErrorMessage(err: unknown): string {
+    if (err instanceof Error) return err.message;
+    return String(err);
+  }
 }