//! Purchases made without an account.
//!
//! A guest purchase lands with `buyer_id` NULL, identified by its claim and
//! download tokens, and is attached to an account out of band once the buyer
//! verifies the email it was bought with. These are the only queries that
//! touch `claim_token`, `download_token` or `guest_email`.

use super::super::{
    Cents, ClaimToken, DbTransaction, DownloadToken, ItemId, PgPool, ProjectId, PromoCodeId,
    Result, TransactionId, UserId,
};

/// Complete a guest transaction: mark it completed, record the guest email, and
/// mint a `claim_token` so the buyer can later attach the purchase to an account.
///
/// Guest purchases always land unclaimed (`buyer_id` NULL); attachment to a user
/// happens out of band via [`attach_guest_purchases_by_email`] at signup/email
/// verification.
#[tracing::instrument(skip_all)]
pub async fn complete_guest_transaction<'e>(
    executor: impl sqlx::PgExecutor<'e>,
    stripe_checkout_session_id: &str,
    stripe_payment_intent_id: Option<&str>,
    guest_email: &str,
) -> Result<Option<DbTransaction>> {
    let claim_token = ClaimToken::new();

    let tx = sqlx::query_as!(
        DbTransaction,
        r#"
        UPDATE transactions
        SET status = 'completed',
            stripe_payment_intent_id = $2,
            completed_at = NOW(),
            guest_email = $3,
            claim_token = $4,
            buyer_id = NULL
        WHERE stripe_checkout_session_id = $1
          AND status = 'pending'
        RETURNING
            id AS "id: TransactionId", buyer_id AS "buyer_id: UserId", seller_id AS "seller_id: UserId",
            item_id AS "item_id: ItemId", amount_cents AS "amount_cents: Cents", platform_fee_cents AS "platform_fee_cents: Cents",
            currency, status AS "status: crate::db::TransactionStatus", stripe_payment_intent_id, stripe_checkout_session_id,
            created_at AS "created_at: chrono::DateTime<chrono::Utc>", completed_at AS "completed_at: chrono::DateTime<chrono::Utc>",
            item_title, seller_username, share_contact, project_id AS "project_id: ProjectId",
            parent_transaction_id AS "parent_transaction_id: TransactionId", promo_code_id AS "promo_code_id: PromoCodeId",
            guest_email, claim_token AS "claim_token: ClaimToken", claimed_by AS "claimed_by: UserId",
            download_token AS "download_token: DownloadToken",
            presentment_amount_cents, presentment_currency
        "#,
        stripe_checkout_session_id,
        stripe_payment_intent_id,
        guest_email,
        claim_token as ClaimToken,
    )
    .fetch_optional(executor)
    .await?;

    Ok(tx)
}

/// Attach all unclaimed guest purchases for an email to a user account.
/// Called during signup/email verification to auto-claim prior guest purchases.
#[tracing::instrument(skip_all)]
pub async fn attach_guest_purchases_by_email(
    pool: &PgPool,
    email: &str,
    user_id: UserId,
) -> Result<u64> {
    let result = sqlx::query!(
        r#"
        UPDATE transactions
        SET buyer_id = $1, claimed_by = $1, claim_token = NULL
        WHERE LOWER(guest_email) = LOWER($2)
          AND buyer_id IS NULL
          AND status = 'completed'
        "#,
        user_id as UserId,
        email,
    )
    .execute(pool)
    .await?;

    Ok(result.rows_affected())
}

/// Claim a single guest purchase by claim token.
#[tracing::instrument(skip_all)]
pub async fn claim_guest_purchase(
    pool: &PgPool,
    claim_token: ClaimToken,
    user_id: UserId,
) -> Result<Option<DbTransaction>> {
    let tx = sqlx::query_as!(
        DbTransaction,
        r#"
        UPDATE transactions
        SET buyer_id = $2, claimed_by = $2, claim_token = NULL
        WHERE claim_token = $1
          AND buyer_id IS NULL
          AND status = 'completed'
        RETURNING
            id AS "id: TransactionId", buyer_id AS "buyer_id: UserId", seller_id AS "seller_id: UserId",
            item_id AS "item_id: ItemId", amount_cents AS "amount_cents: Cents", platform_fee_cents AS "platform_fee_cents: Cents",
            currency, status AS "status: crate::db::TransactionStatus", stripe_payment_intent_id, stripe_checkout_session_id,
            created_at AS "created_at: chrono::DateTime<chrono::Utc>", completed_at AS "completed_at: chrono::DateTime<chrono::Utc>",
            item_title, seller_username, share_contact, project_id AS "project_id: ProjectId",
            parent_transaction_id AS "parent_transaction_id: TransactionId", promo_code_id AS "promo_code_id: PromoCodeId",
            guest_email, claim_token AS "claim_token: ClaimToken", claimed_by AS "claimed_by: UserId",
            download_token AS "download_token: DownloadToken",
            presentment_amount_cents, presentment_currency
        "#,
        claim_token as ClaimToken,
        user_id as UserId,
    )
    .fetch_optional(pool)
    .await?;

    Ok(tx)
}

/// Look up a completed transaction by download token (for guest download links).
#[tracing::instrument(skip_all)]
pub async fn get_transaction_by_download_token(
    pool: &PgPool,
    download_token: DownloadToken,
) -> Result<Option<DbTransaction>> {
    let tx = sqlx::query_as!(
        DbTransaction,
        r#"
        SELECT
            id AS "id: TransactionId", buyer_id AS "buyer_id: UserId", seller_id AS "seller_id: UserId",
            item_id AS "item_id: ItemId", amount_cents AS "amount_cents: Cents", platform_fee_cents AS "platform_fee_cents: Cents",
            currency, status AS "status: crate::db::TransactionStatus", stripe_payment_intent_id, stripe_checkout_session_id,
            created_at AS "created_at: chrono::DateTime<chrono::Utc>", completed_at AS "completed_at: chrono::DateTime<chrono::Utc>",
            item_title, seller_username, share_contact, project_id AS "project_id: ProjectId",
            parent_transaction_id AS "parent_transaction_id: TransactionId", promo_code_id AS "promo_code_id: PromoCodeId",
            guest_email, claim_token AS "claim_token: ClaimToken", claimed_by AS "claimed_by: UserId",
            download_token AS "download_token: DownloadToken",
            presentment_amount_cents, presentment_currency
        FROM transactions WHERE download_token = $1 AND status = 'completed'
        "#,
        download_token as DownloadToken,
    )
    .fetch_optional(pool)
    .await?;

    Ok(tx)
}

/// Create a completed free guest transaction.
///
/// Returns the number of rows inserted (0 if already claimed via ON CONFLICT).
#[allow(clippy::too_many_arguments)]
#[tracing::instrument(skip_all)]
pub async fn create_free_guest_transaction(
    pool: &PgPool,
    buyer_id: Option<UserId>,
    seller_id: UserId,
    item_id: ItemId,
    checkout_session_id: &str,
    item_title: &str,
    seller_username: &str,
    guest_email: &str,
    claim_token: Option<ClaimToken>,
    download_token: DownloadToken,
) -> std::result::Result<u64, sqlx::Error> {
    let result = sqlx::query!(
        r#"
        INSERT INTO transactions (
            buyer_id, seller_id, item_id, amount_cents, platform_fee_cents,
            stripe_checkout_session_id, status, completed_at,
            item_title, seller_username, share_contact,
            guest_email, claim_token, download_token
        )
        VALUES ($1, $2, $3, 0, 0, $4, 'completed', NOW(), $5, $6, false, $7, $8, $9)
        ON CONFLICT (guest_email, item_id) WHERE status = 'completed' AND guest_email IS NOT NULL DO NOTHING
        "#,
        buyer_id as Option<UserId>,
        seller_id as UserId,
        item_id as ItemId,
        checkout_session_id,
        item_title,
        seller_username,
        guest_email,
        claim_token as Option<ClaimToken>,
        download_token as DownloadToken,
    )
    .execute(pool)
    .await?;

    Ok(result.rows_affected())
}