生成AI検索最適化（GEO / AEO）の3原則と構造化データ設計：
〜ChatGPT・Gemini・Perplexityが3秒で貴社の強みを推薦するWebの仕組み〜

#![forbid(unsafe_code)]

#[derive(Clone, Copy, Debug)]
pub struct DocumentChunkMetrics {
    pub bm25_rank: u32,
    pub dense_rank: u32,
    pub has_jsonld_id_graph: bool,
    pub verifiable_credential_count: u8,
    pub ttfb_ms: u16,
}

/// Computes Reciprocal Rank Fusion (RRF, k0 = 60) scaled by 1_000_000
/// plus E-E-A-T Knowledge Graph grounding weight.
pub const fn compute_aeo_citation_score_micro(m: DocumentChunkMetrics) -> u64 {
    let k0 = 60u64;
    let rrf_bm25 = 1_000_000u64 / (k0 + (m.bm25_rank as u64));
    let rrf_dense = 1_000_000u64 / (k0 + (m.dense_rank as u64));
    let base_rrf = rrf_bm25 + rrf_dense;

    let graph_bonus = if m.has_jsonld_id_graph { 135u64 } else { 100u64 };
    let cred_bonus = 100u64 + (m.verifiable_credential_count as u64) * 2;
    let latency_factor = if m.ttfb_ms <= 400 { 110u64 } else { 85u64 };

    (base_rrf * graph_bonus * cred_bonus * latency_factor) / 1_000_000
}

#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn test_ok_2026_domination_score() {
        let ok_page = DocumentChunkMetrics {
            bm25_rank: 1,
            dense_rank: 1,
            has_jsonld_id_graph: true,
            verifiable_credential_count: 20,
            ttfb_ms: 120,
        };
        let legacy_wp = DocumentChunkMetrics {
            bm25_rank: 12,
            dense_rank: 15,
            has_jsonld_id_graph: false,
            verifiable_credential_count: 0,
            ttfb_ms: 2400,
        };
        assert!(compute_aeo_citation_score_micro(ok_page) > compute_aeo_citation_score_micro(legacy_wp) * 2);
    }
}