//! Item media metadata: post-upload file-size writebacks and per-content-type
//! S3 key/URL/metadata updates (audio, cover, video).

use sqlx::PgPool;

use crate::db::models::DbItem;
use crate::db::{ItemId, UserId};
use crate::error::{AppError, Result};

/// Outcome of [`update_item_file_cas`].
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum FileConfirmOutcome {
    /// The compare-and-swap matched: the new key/size were written.
    Committed,
    /// The target s3 column no longer held the expected key (a concurrent
    /// confirm won the race) or the item/owner no longer matched. The caller
    /// MUST NOT credit storage and should treat the staged object as an orphan.
    LostRace,
}

/// Confirm an uploaded item file onto its `items` row with a compare-and-swap.
///
/// This is the guarded write for the generic item-file columns (audio/video
/// key + size), and the one every upload-confirm handler goes through. Raw
/// `UPDATE items SET <col> = ...` stays out of the handlers so none can
/// hand-roll an unguarded write missing the `IS NOT DISTINCT FROM` guard the
/// sibling version-confirm path has. Two writers touch the same columns without going through here:
/// `update_item_video_s3_key` below, which sets the key alone under an
/// ownership filter, and `db::scanning::promote_gated`, which writes
/// `audio_s3_key`/`video_s3_key` with neither a CAS predicate nor an
/// ownership filter.
///
/// The CAS predicate (`<s3_col> IS NOT DISTINCT FROM expected_old_key`) updates
/// the row only if the column still holds the key the caller observed (`NULL`
/// for a first upload). A concurrent confirm that already swapped the column in
/// makes this match zero rows -> [`FileConfirmOutcome::LostRace`], so storage is
/// never double-credited and a live object is never clobbered.
///
/// Takes any `PgExecutor` so the caller can run it inside the same transaction
/// as the storage credit (a rollback then undoes both atomically).
pub async fn update_item_file_cas<'e>(
    executor: impl sqlx::PgExecutor<'e>,
    item_id: ItemId,
    owner: UserId,
    file_type: crate::storage::FileType,
    expected_old_key: Option<&str>,
    new_key: &str,
    size: i64,
) -> Result<FileConfirmOutcome> {
    use crate::storage::GenericItemConfirm;

    // Column names come from the exhaustive `generic_item_confirm` match,
    // `&'static str`, never user input, so the `format!` is injection-safe.
    let (s3_col, size_col) = match file_type.generic_item_confirm() {
        GenericItemConfirm::Columns { s3_key, size } => (s3_key, size),
        GenericItemConfirm::UseRoute(route) => {
            // The generic confirm handler rejects these before reaching here;
            // a call with such a type is a programming error, not user input.
            return Err(AppError::Internal(anyhow::anyhow!(
                "update_item_file_cas called for {} which must use {route}",
                file_type.as_str()
            )));
        }
    };

    let sql = format!(
        "UPDATE items SET {s3_col} = $2, {size_col} = $3, updated_at = NOW() \
         WHERE id = $1 \
           AND project_id IN (SELECT id FROM projects WHERE user_id = $4) \
           AND {s3_col} IS NOT DISTINCT FROM $5"
    );
    let res = sqlx::query(&sql)
        .bind(item_id)
        .bind(new_key)
        .bind(size)
        .bind(owner)
        .bind(expected_old_key)
        .execute(executor)
        .await?;

    Ok(if res.rows_affected() == 0 {
        FileConfirmOutcome::LostRace
    } else {
        FileConfirmOutcome::Committed
    })
}

/// Get the audio, cover, and video file sizes for an item (for storage decrement on delete).
#[tracing::instrument(skip_all)]
pub async fn get_item_file_sizes(
    pool: &PgPool,
    id: ItemId,
) -> Result<crate::db::models::ItemFileSizes> {
    let row = sqlx::query_as::<_, (Option<i64>, Option<i64>, Option<i64>)>(
        "SELECT audio_file_size_bytes, cover_file_size_bytes, video_file_size_bytes FROM items WHERE id = $1",
    )
    .bind(id)
    .fetch_optional(pool)
    .await?;

    match row {
        Some((audio, cover, video)) => Ok(crate::db::models::ItemFileSizes {
            audio_file_size_bytes: audio,
            cover_file_size_bytes: cover,
            video_file_size_bytes: video,
        }),
        None => Ok(crate::db::models::ItemFileSizes {
            audio_file_size_bytes: None,
            cover_file_size_bytes: None,
            video_file_size_bytes: None,
        }),
    }
}

/// Update the audio file size on an item (defense-in-depth: verifies ownership).
#[tracing::instrument(skip_all)]
pub async fn update_item_audio_file_size(
    pool: &PgPool,
    item_id: ItemId,
    user_id: UserId,
    bytes: i64,
) -> Result<()> {
    sqlx::query(
        "UPDATE items SET audio_file_size_bytes = $2 WHERE id = $1 AND project_id IN (SELECT id FROM projects WHERE user_id = $3)",
    )
    .bind(item_id)
    .bind(bytes)
    .bind(user_id)
    .execute(pool)
    .await?;

    Ok(())
}

/// Atomically update cover image URL, S3 key, and file size in a single UPDATE
/// (defense-in-depth: verifies ownership), guarded by a compare-and-swap on the
/// existing `cover_s3_key`.
///
/// Returns `true` when the row was actually updated, `false` when the UPDATE
/// matched zero rows, either the ownership filter no-matched (item deleted or
/// moved between projects mid-flight) OR the CAS predicate failed because a
/// concurrent confirm already swapped the cover key out from under the value
/// the caller observed (`expected_old_key`, `NULL` for a first cover). Without
/// the CAS, two concurrent cover confirms each deduct the old size and the loser
/// silently orphans its committed object, the same
/// lost-update shape the audio/video path seals via [`update_item_file_cas`].
/// Callers that fire side-effects after the write, storage credit, scan
/// enqueue, S3 orphan queueing, must check the bool and roll back on false.
#[tracing::instrument(skip_all)]
pub async fn update_item_cover<'e>(
    executor: impl sqlx::PgExecutor<'e>,
    item_id: ItemId,
    user_id: UserId,
    expected_old_key: Option<&str>,
    url: &str,
    s3_key: &str,
    file_size_bytes: i64,
) -> Result<bool> {
    let result = sqlx::query(
        r"UPDATE items
           SET cover_image_url = $2, cover_s3_key = $3, cover_file_size_bytes = $4, updated_at = NOW()
           WHERE id = $1
             AND project_id IN (SELECT id FROM projects WHERE user_id = $5)
             AND cover_s3_key IS NOT DISTINCT FROM $6",
    )
    .bind(item_id)
    .bind(url)
    .bind(s3_key)
    .bind(file_size_bytes)
    .bind(user_id)
    .bind(expected_old_key)
    .execute(executor)
    .await?;

    Ok(result.rows_affected() > 0)
}

/// Update the cover file size on an item (defense-in-depth: verifies ownership).
#[tracing::instrument(skip_all)]
pub async fn update_item_cover_file_size(
    pool: &PgPool,
    item_id: ItemId,
    user_id: UserId,
    bytes: i64,
) -> Result<()> {
    sqlx::query(
        "UPDATE items SET cover_file_size_bytes = $2 WHERE id = $1 AND project_id IN (SELECT id FROM projects WHERE user_id = $3)",
    )
    .bind(item_id)
    .bind(bytes)
    .bind(user_id)
    .execute(pool)
    .await?;

    Ok(())
}

/// Update the video S3 key for an item (defense-in-depth: verifies ownership).
#[tracing::instrument(skip_all)]
pub async fn update_item_video_s3_key(
    pool: &PgPool,
    item_id: ItemId,
    user_id: UserId,
    s3_key: &str,
) -> Result<DbItem> {
    let item = sqlx::query_as::<_, DbItem>(
        r"
        UPDATE items
        SET video_s3_key = $2, updated_at = NOW()
        WHERE id = $1
          AND project_id IN (SELECT id FROM projects WHERE user_id = $3)
        RETURNING *
        ",
    )
    .bind(item_id)
    .bind(s3_key)
    .bind(user_id)
    .fetch_one(pool)
    .await?;

    Ok(item)
}

/// Update the video file size on an item (defense-in-depth: verifies ownership).
#[tracing::instrument(skip_all)]
pub async fn update_item_video_file_size(
    pool: &PgPool,
    item_id: ItemId,
    user_id: UserId,
    bytes: i64,
) -> Result<()> {
    sqlx::query(
        "UPDATE items SET video_file_size_bytes = $2 WHERE id = $1 AND project_id IN (SELECT id FROM projects WHERE user_id = $3)",
    )
    .bind(item_id)
    .bind(bytes)
    .bind(user_id)
    .execute(pool)
    .await?;

    Ok(())
}

/// Update video metadata (duration, resolution) on an item (defense-in-depth: verifies ownership).
#[tracing::instrument(skip_all)]
pub async fn update_item_video_metadata(
    pool: &PgPool,
    item_id: ItemId,
    user_id: UserId,
    duration_seconds: Option<i32>,
    width: Option<i32>,
    height: Option<i32>,
) -> Result<()> {
    sqlx::query(
        r"
        UPDATE items
        SET video_duration_seconds = $2, video_width = $3, video_height = $4, updated_at = NOW()
        WHERE id = $1
          AND project_id IN (SELECT id FROM projects WHERE user_id = $5)
        ",
    )
    .bind(item_id)
    .bind(duration_seconds)
    .bind(width)
    .bind(height)
    .bind(user_id)
    .execute(pool)
    .await?;

    Ok(())
}