Content-Hunter_BE/src/modules/seo/seo.service.ts

// SEO Service - Main orchestration service
// Path: src/modules/seo/seo.service.ts

import { Injectable, Logger } from '@nestjs/common';
import { KeywordResearchService, Keyword, KeywordCluster } from './services/keyword-research.service';
import { ContentOptimizationService, SeoScore, OptimizedMeta } from './services/content-optimization.service';
import { CompetitorAnalysisService, ContentGap, CompetitorProfile } from './services/competitor-analysis.service';

export interface FullSeoAnalysis {
    content: {
        score: SeoScore;
        meta: OptimizedMeta;
    };
    keywords: {
        main: Keyword;
        related: Keyword[];
        clusters: KeywordCluster[];
        longTail: ReturnType<KeywordResearchService['generateLongTail']>;
    };
    competitors: {
        gaps: ContentGap[];
    };
}

@Injectable()
export class SeoService {
    private readonly logger = new Logger(SeoService.name);

    constructor(
        private readonly keywordService: KeywordResearchService,
        private readonly optimizationService: ContentOptimizationService,
        private readonly competitorService: CompetitorAnalysisService,
    ) { }

    /**
     * Full SEO analysis for content
     */
    async analyzeFull(
        content: string,
        targetKeyword: string,
        options?: {
            title?: string;
            metaDescription?: string;
            url?: string;
            competitorDomains?: string[];
        },
    ): Promise<FullSeoAnalysis> {
        // Analyze content
        const score = this.optimizationService.analyze(content, {
            targetKeyword,
            title: options?.title,
            metaDescription: options?.metaDescription,
            url: options?.url,
        });

        // Generate optimized meta
        const meta = this.optimizationService.generateMeta(content, targetKeyword);

        // Research keywords
        const keywordData = await this.keywordService.suggestKeywords(targetKeyword, {
            count: 20,
            includeQuestions: true,
            includeLongTail: true,
        });

        // Cluster keywords
        const allKeywords = [targetKeyword, ...keywordData.related.map((k) => k.term)];
        const clusters = this.keywordService.clusterKeywords(allKeywords);

        // Long-tail variations
        const longTail = this.keywordService.generateLongTail(targetKeyword, 15);

        // Content gaps (if competitors provided)
        let gaps: ContentGap[] = [];
        if (options?.competitorDomains?.length) {
            gaps = await this.competitorService.findContentGaps(
                allKeywords,
                options.competitorDomains,
            );
        }

        return {
            content: { score, meta },
            keywords: {
                main: keywordData.main,
                related: keywordData.related,
                clusters,
                longTail,
            },
            competitors: { gaps },
        };
    }

    /**
     * Quick SEO score check
     */
    quickScore(content: string, targetKeyword?: string): number {
        const analysis = this.optimizationService.analyze(content, { targetKeyword });
        return analysis.overall;
    }

    /**
     * Generate SEO-optimized content outline
     */
    async generateOutline(
        keyword: string,
        options?: {
            competitorDomains?: string[];
            contentType?: string;
        },
    ): Promise<{
        title: string;
        description: string;
        headings: string[];
        keywords: string[];
        estimatedWordCount: number;
        differentiators: string[];
    }> {
        // Get keyword data
        const keywordData = await this.keywordService.suggestKeywords(keyword);

        // Get title variations
        const titles = this.optimizationService.generateTitleVariations(keyword, 1);
        const descriptions = this.optimizationService.generateDescriptionVariations(keyword, '', 1);

        // Generate outline if competitors provided
        let headings: string[] = [];
        let differentiators: string[] = [];

        if (options?.competitorDomains?.length) {
            const competitorContent = await this.competitorService.analyzeTopContent(keyword, 5);
            const blueprint = this.competitorService.generateContentBlueprint(keyword, competitorContent);
            headings = blueprint.suggestedHeadings;
            differentiators = blueprint.differentiators;
        } else {
            headings = [
                `What is ${keyword}?`,
                `Why ${keyword} is Important`,
                `How to Use ${keyword}`,
                `${keyword} Best Practices`,
                `Common ${keyword} Mistakes`,
                `${keyword} Tools & Resources`,
                `FAQs about ${keyword}`,
            ];
            differentiators = [
                'Include original research or data',
                'Add expert insights',
                'Provide actionable steps',
                'Include real examples',
            ];
        }

        return {
            title: titles[0] || `Complete Guide to ${keyword}`,
            description: descriptions[0] || `Learn everything about ${keyword} in this comprehensive guide.`,
            headings,
            keywords: [keyword, ...keywordData.related.slice(0, 5).map((k) => k.term)],
            estimatedWordCount: 1500,
            differentiators,
        };
    }

    /**
     * Get LSI keywords for semantic SEO
     */
    getLSIKeywords(keyword: string, count: number = 10): string[] {
        return this.keywordService.generateLSIKeywords(keyword, count);
    }

    /**
     * Analyze keyword difficulty
     */
    analyzeKeywordDifficulty(keyword: string) {
        return this.keywordService.analyzeKeywordDifficulty(keyword);
    }

    /**
     * Check for keyword cannibalization
     */
    checkCannibalization(newKeyword: string, existingKeywords: string[]) {
        return this.optimizationService.checkCannibalization(newKeyword, existingKeywords);
    }

    /**
     * Get competitor insights
     */
    async getCompetitorInsights(domain: string): Promise<CompetitorProfile> {
        return this.competitorService.analyzeCompetitor(domain);
    }
}