import sqlite3
import numpy as np
from app.shared.config import Settings
from app.pipeline.recognition import unpack_embedding, cosine_similarity


def cluster_unknown_speakers(settings: Settings, db: sqlite3.Connection) -> None:
    """
    Groups unknown/ambiguous utterances from the last 7 days by voice similarity.
    Assigns speaker_id from an existing 'Unknown #N' speaker or creates a new one.
    Threshold: 0.70 cosine similarity.
    """
    CLUSTER_THRESHOLD = 0.70

    rows = db.execute("""
        SELECT id, embedding FROM utterances
        WHERE match_status IN ('unknown', 'ambiguous')
          AND embedding IS NOT NULL
          AND date(start_time) >= date('now', '-7 days')
        ORDER BY start_time ASC
    """).fetchall()

    if not rows:
        return

    clusters: list = []
    cluster_centroids: list = []

    for row in rows:
        emb = unpack_embedding(row["embedding"])
        best_cluster = None
        best_sim = 0.0
        for i, centroid in enumerate(cluster_centroids):
            sim = cosine_similarity(emb, centroid)
            if sim > best_sim and sim >= CLUSTER_THRESHOLD:
                best_sim = sim
                best_cluster = i
        if best_cluster is not None:
            clusters[best_cluster].append(row["id"])
            n = len(clusters[best_cluster])
            cluster_centroids[best_cluster] = (
                (cluster_centroids[best_cluster] * (n - 1) + emb) / n
            )
        else:
            clusters.append([row["id"]])
            cluster_centroids.append(emb)

    for i, cluster in enumerate(clusters):
        if len(cluster) < 2:
            continue
        name = f"Unknown #{i + 1}"
        existing = db.execute("SELECT id FROM speakers WHERE name=?", (name,)).fetchone()
        if existing:
            speaker_id = existing["id"]
        else:
            cur = db.execute("INSERT INTO speakers (name) VALUES (?)", (name,))
            db.commit()
            speaker_id = cur.lastrowid
        for utt_id in cluster:
            db.execute(
                "UPDATE utterances SET speaker_id=?, match_status='ambiguous' WHERE id=?",
                (speaker_id, utt_id),
            )
    db.commit()