// TTS-pipeline — tekst til lyd via ElevenLabs.
//
// Jobbtype: "tts_generate"
// Payload: {
//   "text": "<tekst som skal leses opp>",
//   "voice_id": "<elevenlabs voice_id>",  (valgfritt, bruker default)
//   "language": "no",                      (valgfritt)
//   "source_node_id": "<uuid>",           (noden teksten tilhører)
//   "requested_by": "<uuid>"
// }
//
// Flyten:
// 1. Hent tekst og voice-preferanse fra payload
// 2. Sjekk mottaker-preferanse i source-nodens metadata (voice_preference)
// 3. Kall ElevenLabs API
// 4. Lagre lyd i CAS
// 5. Opprett media-node med has_media-edge til kilde
// 6. Logg ressursforbruk
//
// Ref: docs/features/ressursforbruk.md, docs/proposals/ghost_host_tts.md

use sqlx::PgPool;
use uuid::Uuid;

use crate::cas::CasStore;
use crate::jobs::JobRow;
use crate::stdb::StdbClient;

/// Maks tekst-lengde for TTS (ElevenLabs grense er 5000 tegn per kall).
const MAX_TEXT_LENGTH: usize = 5000;

/// Håndterer tts_generate-jobb.
pub async fn handle_tts_job(
    job: &JobRow,
    db: &PgPool,
    stdb: &StdbClient,
    cas: &CasStore,
) -> Result<serde_json::Value, String> {
    let text = job.payload["text"]
        .as_str()
        .ok_or("Mangler 'text' i payload")?
        .to_string();

    if text.is_empty() {
        return Err("Tom tekst — ingenting å generere".to_string());
    }
    if text.len() > MAX_TEXT_LENGTH {
        return Err(format!(
            "Tekst for lang: {} tegn (maks {})",
            text.len(),
            MAX_TEXT_LENGTH
        ));
    }

    let source_node_id: Option<Uuid> = job.payload["source_node_id"]
        .as_str()
        .and_then(|s| s.parse().ok());

    let requested_by: Uuid = job.payload["requested_by"]
        .as_str()
        .and_then(|s| s.parse().ok())
        .ok_or("Mangler gyldig 'requested_by' i payload")?;

    // Bestem voice_id: payload > source-node metadata > env default
    let voice_id = resolve_voice_id(job, db, source_node_id).await?;

    let language = job.payload["language"]
        .as_str()
        .unwrap_or("no")
        .to_string();

    tracing::info!(
        text_len = text.len(),
        voice_id = %voice_id,
        language = %language,
        "Starter TTS-generering"
    );

    // 1. Kall ElevenLabs API
    let audio_bytes = call_elevenlabs(&text, &voice_id).await?;

    tracing::info!(
        audio_size = audio_bytes.len(),
        "Mottok lyd fra ElevenLabs"
    );

    // 2. Lagre i CAS
    let cas_result = cas
        .store(&audio_bytes)
        .await
        .map_err(|e| format!("CAS-lagring feilet: {e}"))?;

    tracing::info!(
        cas_hash = %cas_result.hash,
        size = cas_result.size,
        dedup = cas_result.already_existed,
        "Lyd lagret i CAS"
    );

    // 3. Opprett media-node for lydfilen
    let media_node_id = Uuid::now_v7();
    let title = format!("TTS: {}", truncate(&text, 60));
    let metadata = serde_json::json!({
        "cas_hash": cas_result.hash,
        "mime": "audio/mpeg",
        "size_bytes": cas_result.size,
        "tts": {
            "provider": "elevenlabs",
            "voice_id": voice_id,
            "language": language,
            "characters": text.len(),
        }
    });
    let metadata_str = metadata.to_string();

    // STDB først (sanntid)
    stdb.create_node(
        &media_node_id.to_string(),
        "content",
        &title,
        "",
        "hidden",
        &metadata_str,
        &requested_by.to_string(),
    )
    .await
    .map_err(|e| format!("STDB create_node feilet: {e}"))?;

    // PG (persistering)
    sqlx::query(
        r#"
        INSERT INTO nodes (id, node_kind, title, content, visibility, metadata, created_by)
        VALUES ($1, 'content', $2, '', 'hidden'::visibility, $3, $4)
        "#,
    )
    .bind(media_node_id)
    .bind(&title)
    .bind(&metadata)
    .bind(requested_by)
    .execute(db)
    .await
    .map_err(|e| format!("PG insert media-node feilet: {e}"))?;

    // 4. Opprett has_media-edge fra kilde-node til TTS-noden (hvis kilde finnes)
    if let Some(source_id) = source_node_id {
        let edge_id = Uuid::now_v7();
        let edge_meta = serde_json::json!({
            "media_type": "tts_audio",
            "generated_at": chrono::Utc::now().to_rfc3339()
        });
        let empty_meta = edge_meta.to_string();

        stdb.create_edge(
            &edge_id.to_string(),
            &source_id.to_string(),
            &media_node_id.to_string(),
            "has_media",
            &empty_meta,
            false,
            &requested_by.to_string(),
        )
        .await
        .map_err(|e| format!("STDB create_edge (has_media) feilet: {e}"))?;

        sqlx::query(
            r#"
            INSERT INTO edges (id, source_id, target_id, edge_type, metadata, system, created_by)
            VALUES ($1, $2, $3, 'has_media', $4, false, $5)
            "#,
        )
        .bind(edge_id)
        .bind(source_id)
        .bind(media_node_id)
        .bind(&edge_meta)
        .bind(requested_by)
        .execute(db)
        .await
        .map_err(|e| format!("PG insert has_media-edge feilet: {e}"))?;
    }

    // 5. Logg ressursforbruk
    sqlx::query(
        r#"
        INSERT INTO resource_usage_log (target_node_id, triggered_by, resource_type, detail)
        VALUES ($1, $2, 'tts', $3)
        "#,
    )
    .bind(media_node_id)
    .bind(requested_by)
    .bind(serde_json::json!({
        "provider": "elevenlabs",
        "characters": text.len(),
        "voice_id": voice_id
    }))
    .execute(db)
    .await
    .map_err(|e| format!("Ressurslogging feilet: {e}"))?;

    Ok(serde_json::json!({
        "status": "completed",
        "media_node_id": media_node_id.to_string(),
        "cas_hash": cas_result.hash,
        "characters": text.len(),
        "audio_size_bytes": cas_result.size,
        "voice_id": voice_id,
    }))
}

/// Bestem voice_id: payload-verdi > source-node metadata.voice_preference > env default.
/// "Mottaker-preferanse i metadata" betyr at en node kan ha
/// metadata.voice_preference.voice_id som overstyrer default.
async fn resolve_voice_id(
    job: &JobRow,
    db: &PgPool,
    source_node_id: Option<Uuid>,
) -> Result<String, String> {
    // 1. Eksplisitt i payload — alltid høyest prioritet
    if let Some(vid) = job.payload["voice_id"].as_str() {
        if !vid.is_empty() {
            return Ok(vid.to_string());
        }
    }

    // 2. Sjekk source-nodens metadata.voice_preference.voice_id
    if let Some(node_id) = source_node_id {
        let meta: Option<serde_json::Value> = sqlx::query_scalar(
            "SELECT metadata FROM nodes WHERE id = $1",
        )
        .bind(node_id)
        .fetch_optional(db)
        .await
        .map_err(|e| format!("PG-feil ved henting av voice_preference: {e}"))?
        .flatten();

        if let Some(meta) = meta {
            if let Some(vid) = meta
                .get("voice_preference")
                .and_then(|vp| vp.get("voice_id"))
                .and_then(|v| v.as_str())
            {
                if !vid.is_empty() {
                    tracing::info!(
                        node_id = %node_id,
                        voice_id = %vid,
                        "Bruker mottaker-preferanse fra node-metadata"
                    );
                    return Ok(vid.to_string());
                }
            }
        }
    }

    // 3. Miljøvariabel-default
    let default = std::env::var("ELEVENLABS_DEFAULT_VOICE")
        .unwrap_or_else(|_| "21m00Tcm4TlvDq8ikWAM".to_string()); // Rachel (ElevenLabs premade)

    Ok(default)
}

/// Kall ElevenLabs text-to-speech API.
/// Returnerer rå MP3-bytes.
async fn call_elevenlabs(text: &str, voice_id: &str) -> Result<Vec<u8>, String> {
    let api_key = std::env::var("ELEVENLABS_API_KEY")
        .map_err(|_| "ELEVENLABS_API_KEY er ikke satt".to_string())?;

    let model_id = std::env::var("ELEVENLABS_MODEL")
        .unwrap_or_else(|_| "eleven_multilingual_v2".to_string());

    let url = format!(
        "https://api.elevenlabs.io/v1/text-to-speech/{voice_id}"
    );

    let payload = serde_json::json!({
        "text": text,
        "model_id": model_id,
        "voice_settings": {
            "stability": 0.5,
            "similarity_boost": 0.75,
            "style": 0.0,
            "use_speaker_boost": true
        }
    });

    let client = reqwest::Client::new();
    let resp = client
        .post(&url)
        .header("xi-api-key", &api_key)
        .header("Accept", "audio/mpeg")
        .json(&payload)
        .timeout(std::time::Duration::from_secs(30))
        .send()
        .await
        .map_err(|e| format!("ElevenLabs HTTP-feil: {e}"))?;

    if !resp.status().is_success() {
        let status = resp.status();
        let body = resp.text().await.unwrap_or_default();
        return Err(format!("ElevenLabs returnerte {status}: {body}"));
    }

    resp.bytes()
        .await
        .map(|b| b.to_vec())
        .map_err(|e| format!("Kunne ikke lese ElevenLabs-respons: {e}"))
}

/// Forkorter en streng til maks `max_len` tegn med "..." suffix.
fn truncate(s: &str, max_len: usize) -> String {
    if s.len() <= max_len {
        s.to_string()
    } else {
        let end = s.char_indices().nth(max_len - 3).map(|(i, _)| i).unwrap_or(s.len());
        format!("{}...", &s[..end])
    }
}