apps/backend/src/services/external/OutlookJsonAdapter.ts

import { DataSourceAdapter, type IngestedEntity } from '../ingestion/DataIngestionEngine.js';
import { readFile } from 'fs/promises';
import { existsSync } from 'fs';

interface OutlookEmail {
    id: string;
    subject: string;
    sender: {
        name: string;
        address: string;
    };
    receivedDateTime: string;
    bodyPreview: string;
    body: {
        contentType: string;
        content: string;
    };
    importance: 'low' | 'normal' | 'high';
    isRead: boolean;
}

export class OutlookJsonAdapter implements DataSourceAdapter {
    name = 'Outlook';
    type: 'outlook_mail' = 'outlook_mail';
    private filePath: string;
    private emails: OutlookEmail[] = [];
    private lastLoaded: number = 0;

    constructor(filePath: string) {
        this.filePath = filePath;
    }

    /**
     * Loads emails from the local JSON file
     */
    private async loadEmails(): Promise<void> {
        if (!existsSync(this.filePath)) {
            console.warn(`[OutlookJsonAdapter] File not found: ${this.filePath}`);
            this.emails = [];
            return;
        }

        try {
            const data = await readFile(this.filePath, 'utf-8');
            // Handle potential wrapping structures (e.g. { value: [...] } or just [...])
            const json = JSON.parse(data);
            this.emails = Array.isArray(json) ? json : (json.value || []);
            this.lastLoaded = Date.now();
            console.log(`[OutlookJsonAdapter] Loaded ${this.emails.length} emails from ${this.filePath}`);
        } catch (error) {
            console.error(`[OutlookJsonAdapter] Failed to parse JSON:`, error);
            this.emails = [];
        }
    }

    /**
     * Fetch emails, reloading if cache is stale (> 5 minutes)
     */
    async fetch(): Promise<any[]> {
        const STALE_THRESHOLD = 5 * 60 * 1000; // 5 minutes
        if (this.emails.length === 0 || Date.now() - this.lastLoaded > STALE_THRESHOLD) {
            await this.loadEmails();
        }
        return this.emails;
    }

    /**
     * Transform Outlook emails to Unified Memory entities
     */
    async transform(raw: any[]): Promise<IngestedEntity[]> {
        return raw.map((email: OutlookEmail) => ({
            id: email.id,
            type: 'email',
            source: 'Outlook',
            title: email.subject,
            content: `${email.subject}\n\nFrom: ${email.sender.name} <${email.sender.address}>\nDate: ${email.receivedDateTime}\n\n${email.bodyPreview}`,
            metadata: {
                subject: email.subject,
                sender: email.sender.address,
                senderName: email.sender.name,
                receivedAt: email.receivedDateTime,
                importance: email.importance,
                isRead: email.isRead,
                source: 'outlook_json',
            },
            timestamp: new Date(email.receivedDateTime)
        }));
    }

    /**
     * Check if the adapter is available (file exists)
     */
    async isAvailable(): Promise<boolean> {
        return existsSync(this.filePath);
    }

    /**
     * Support direct queries
     */
    async query(operation: string, params: any): Promise<any> {
        await this.fetch(); // Ensure data is loaded

        switch (operation) {
            case 'search':
                const term = params.query?.toLowerCase();
                if (!term) return this.emails.slice(0, params.limit || 10);
                
                return this.emails.filter(e => 
                    e.subject.toLowerCase().includes(term) || 
                    e.sender.name.toLowerCase().includes(term) ||
                    e.bodyPreview.toLowerCase().includes(term)
                ).slice(0, params.limit || 10);
            
            case 'get_latest':
                return this.emails
                    .sort((a, b) => new Date(b.receivedDateTime).getTime() - new Date(a.receivedDateTime).getTime())
                    .slice(0, params.limit || 10);

            case 'get_by_sender':
                const sender = params.sender?.toLowerCase();
                if (!sender) return [];
                return this.emails.filter(e => 
                    e.sender.address.toLowerCase().includes(sender) || 
                    e.sender.name.toLowerCase().includes(sender)
                ).slice(0, params.limit || 10);

            default:
                throw new Error(`Unsupported operation: ${operation}`);
        }
    }
}