//! Feed generator operations
//!
//! This module handles feed generator (custom algorithm) database operations:
//! - Creating/updating feed generators with metadata
//! - Deleting feed generators
//!
//! Feed generators use arbitrary string rkeys (not TIDs), so they are stored as TEXT.

use crate::Result;
use crate::types::records::AppBskyFeedGenerator;
use crate::utils::blob_to_cid_bytes;
use deadpool_postgres::GenericClient;
use eyre::Context as _;
use ipld_core::cid::Cid;

/// Strip lexicon prefix from enum value
///
/// Example: "app.bsky.feed.defs#contentModeUnspecified" -> "contentModeUnspecified"
#[allow(dead_code)]
fn strip_lexicon_prefix(value: &str) -> &str {
    value.split('#').nth(1).unwrap_or(value)
}

/// Insert or update a feed generator record
///
/// Feed generators represent custom algorithm feeds. They include:
/// - owner_actor_id: The feed's owner (from actor_id)
/// - service_actor_id: The service DID that serves the feed
/// - display_name, description, description_facets: Metadata
/// - avatar: Optional avatar blob CID
/// - content_mode: Content filtering mode (e.g., "contentModeUnspecified")
/// - created_at: Timestamp (NOT derived from rkey, provided explicitly)
///
/// IMPORTANT: Feedgens use arbitrary string rkeys (not TIDs), stored as TEXT.
/// Unlike posts/likes/reposts, feedgen rkeys are NOT converted to INT8.
///
/// Returns true if the feedgen was updated (status changed from stub to active).
pub async fn feedgen_upsert<C: GenericClient>(
    conn: &C,
    actor_id: i32,
    rkey: &str,
    cid: Cid,
    service_actor_id: i32,
    rec: AppBskyFeedGenerator,
) -> Result<bool> {
    // Acquire table-scoped advisory lock using actor_id + rkey (string form for feedgens)
    let (table_id, key_id) = crate::database_writer::locking::actor_record_lock_str("feedgens", actor_id, rkey);
    conn.execute(
        "SELECT pg_advisory_xact_lock($1, $2)",
        &[&table_id, &key_id],
    )
    .await?;

    let cid_bytes = cid.to_bytes();
    let cid_digest = parakeet_db::utils::cid::cid_to_digest(&cid_bytes)
        .expect("CID must be valid AT Protocol CID");
    let description_facets = rec
        .description_facets
        .and_then(|v| serde_json::to_value(v).ok());
    let avatar = blob_to_cid_bytes(rec.avatar.as_ref());

    // Note: content_mode field not available in jacquard types
    let content_mode: Option<String> = None;

    conn.query_one(
        include_str!("../../sql/feedgen_upsert.sql"),
        &[
            &actor_id,
            &rkey,  // TEXT rkey (feedgens use arbitrary strings, not TIDs)
            &cid_digest,
            &service_actor_id,
            &content_mode,
            &rec.display_name,
            &rec.description,
            &description_facets,
            &avatar,
            &rec.created_at,
        ],
    )
    .await
    .wrap_err_with(|| format!("Failed to upsert feedgen for actor_id:{} rkey:{}", actor_id, rkey))
    .map(|r| r.get::<_, i32>(0) == 0)
}

/// Delete a feed generator record
///
/// IMPORTANT: Feedgens use arbitrary string rkeys (not TIDs), so NO conversion to INT8.
pub async fn feedgen_delete<C: GenericClient>(
    conn: &C,
    actor_id: i32,
    rkey: &str,
) -> Result<u64> {
    // NOTE: Feedgens use arbitrary string rkeys, not TIDs, so NO conversion to INT8

    conn.execute(
        "DELETE FROM feedgens
         WHERE actor_id = $1
           AND rkey = $2",
        &[&actor_id, &rkey],
    )
    .await
    .wrap_err_with(|| format!("Failed to delete feedgen for actor_id:{} rkey:{}", actor_id, rkey))
}

// NOTE: update_feedgen_like_counts() removed - like_count is now maintained automatically
// by the update_feedgen_like_count() trigger (Phase 8 migration 2025-12-08-152125).
// The trigger fires on INSERT or UPDATE OF like_actor_ids and sets like_count = array_length().

/// Decrement like_count for a single feedgen
///
/// This is called when deleting a feedgen_like record.
/// Note: This function is likely obsolete with Phase 8 triggers that maintain like_count
/// from like_actor_ids[] array. Consider removing if no longer used in production.
pub async fn decrement_feedgen_like_count<C: GenericClient>(
    conn: &C,
    actor_id: i32,
    rkey: &str,
) -> Result<u64> {
    conn.execute(
        "UPDATE feedgens
         SET like_count = GREATEST(like_count - 1, 0)
         WHERE actor_id = $1 AND rkey = $2",
        &[&actor_id, &rkey],
    )
    .await
    .wrap_err("Failed to decrement feedgen like_count")
}