sqldb: add invoice queries

Set of queries to deal with invoices. A couple of things to take into
account:

    - Because the queries are not rewritten at runtime, we cannot have a
      generic `INSERT` with different tuples.
    - Because the queries are not rewritten at runtime, we cannot build
      one query with only the filters that matter for that queries. The
      two options are a combinatorial approach (a new query for every
      permutation) or a generic query using the pattern

          ```
            SELECT *
            FROM table
            WHERE (
                -- Can be read as:
                -- Match the filter 1 value if filter_1 != nil
                column_1 >= sqlc.narg('filter_1') OR
                sqlc.narg('filter_1') IS NULL
            ) AND (
                column_2 >= sqlc.narg('filter_2') OR
                sqlc.narg('filter_2') IS NULL
            ) ...
          ```

sqldb/sqlc/queries/invoices.sql

@@ -0,0 +1,196 @@
+-- name: InsertInvoice :one
+INSERT INTO invoices (
+    hash, preimage, memo, amount_msat, cltv_delta, expiry, payment_addr, 
+    payment_request, state, amount_paid_msat, is_amp, is_hodl, is_keysend, 
+    created_at
+) VALUES (
+    $1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14
+) RETURNING id;
+
+-- name: InsertInvoiceFeature :exec
+INSERT INTO invoice_features (
+    invoice_id, feature
+) VALUES (
+    $1, $2
+);
+
+-- name: GetInvoiceFeatures :many
+SELECT *
+FROM invoice_features
+WHERE invoice_id = $1;
+
+-- name: DeleteInvoiceFeatures :exec
+DELETE 
+FROM invoice_features
+WHERE invoice_id = $1;
+
+-- This method may return more than one invoice if filter using multiple fields
+-- from different invoices. It is the caller's responsibility to ensure that 
+-- we bubble up an error in those cases.
+
+-- name: GetInvoice :many
+SELECT *
+FROM invoices
+WHERE (
+    id = sqlc.narg('add_index') OR 
+    sqlc.narg('add_index') IS NULL
+) AND (
+    hash = sqlc.narg('hash') OR 
+    sqlc.narg('hash') IS NULL
+) AND (
+    preimage = sqlc.narg('preimage') OR 
+    sqlc.narg('preimage') IS NULL
+) AND (
+    payment_addr = sqlc.narg('payment_addr') OR 
+    sqlc.narg('payment_addr') IS NULL
+)
+LIMIT 2;
+
+-- name: FilterInvoices :many
+SELECT * 
+FROM invoices
+WHERE (
+    id >= sqlc.narg('add_index_get') OR 
+    sqlc.narg('add_index_get') IS NULL
+) AND (
+    id <= sqlc.narg('add_index_let') OR 
+    sqlc.narg('add_index_let') IS NULL
+) AND (
+    state = sqlc.narg('state') OR 
+    sqlc.narg('state') IS NULL
+) AND (
+    created_at >= sqlc.narg('created_after') OR
+    sqlc.narg('created_after') IS NULL
+) AND (
+    created_at <= sqlc.narg('created_before') OR 
+    sqlc.narg('created_before') IS NULL
+) AND (
+    CASE
+        WHEN sqlc.narg('pending_only')=TRUE THEN (state = 0 OR state = 3)
+        ELSE TRUE 
+    END
+)
+ORDER BY
+    CASE
+        WHEN sqlc.narg('reverse') = FALSE THEN id  
+        ELSE NULL
+    END ASC,
+    CASE
+        WHEN sqlc.narg('reverse') = TRUE  THEN id  
+        ELSE NULL
+    END DESC
+LIMIT @num_limit OFFSET @num_offset;
+
+-- name: UpdateInvoice :exec 
+UPDATE invoices 
+SET preimage=$2, state=$3, amount_paid_msat=$4
+WHERE id=$1;
+
+-- name: DeleteInvoice :exec
+DELETE 
+FROM invoices 
+WHERE (
+    id = sqlc.narg('add_index') OR 
+    sqlc.narg('add_index') IS NULL
+) AND (
+    hash = sqlc.narg('hash') OR 
+    sqlc.narg('hash') IS NULL
+) AND (
+    preimage = sqlc.narg('preimage') OR 
+    sqlc.narg('preimage') IS NULL
+) AND (
+    payment_addr = sqlc.narg('payment_addr') OR
+    sqlc.narg('payment_addr') IS NULL
+);
+
+-- name: InsertInvoiceHTLC :exec
+INSERT INTO invoice_htlcs (
+    htlc_id, chan_id, amount_msat, total_mpp_msat, accept_height, accept_time,
+    expiry_height, state, resolve_time, invoice_id
+) VALUES (
+    $1, $2, $3, $4, $5, $6, $7, $8, $9, $10
+);
+
+-- name: GetInvoiceHTLCs :many
+SELECT *
+FROM invoice_htlcs
+WHERE invoice_id = $1;
+
+-- name: UpdateInvoiceHTLC :exec
+UPDATE invoice_htlcs 
+SET state=$2, resolve_time=$3
+WHERE id = $1;
+
+-- name: UpdateInvoiceHTLCs :exec
+UPDATE invoice_htlcs 
+SET state=$2, resolve_time=$3
+WHERE invoice_id = $1 AND resolve_time IS NULL;
+
+
+-- name: DeleteInvoiceHTLC :exec
+DELETE
+FROM invoice_htlcs
+WHERE htlc_id = $1;
+
+-- name: DeleteInvoiceHTLCs :exec
+DELETE
+FROM invoice_htlcs
+WHERE invoice_id = $1;
+
+-- name: InsertInvoiceHTLCCustomRecord :exec
+INSERT INTO invoice_htlc_custom_records (
+    key, value, htlc_id 
+) VALUES (
+    $1, $2, $3
+);
+
+-- name: GetInvoiceHTLCCustomRecords :many
+SELECT ihcr.htlc_id, key, value
+FROM invoice_htlcs ih JOIN invoice_htlc_custom_records ihcr ON ih.id=ihcr.htlc_id 
+WHERE ih.invoice_id = $1;
+
+-- name: DeleteInvoiceHTLCCustomRecords :exec
+WITH htlc_ids AS (
+    SELECT ih.id
+    FROM invoice_htlcs ih JOIN invoice_htlc_custom_records ihcr ON ih.id=ihcr.htlc_id 
+    WHERE ih.invoice_id = $1
+)
+DELETE
+FROM invoice_htlc_custom_records
+WHERE htlc_id IN (SELECT id FROM htlc_ids);
+
+-- name: InsertInvoicePayment :one
+INSERT INTO invoice_payments (
+    invoice_id, amount_paid_msat, settled_at 
+) VALUES (
+    $1, $2, $3
+) RETURNING id;
+
+-- name: GetInvoicePayments :many
+SELECT *
+FROM invoice_payments
+WHERE invoice_id = $1;
+
+-- name: FilterInvoicePayments :many
+SELECT  
+    ip.id AS settle_index, ip.amount_paid_msat, ip.settled_at AS settle_date, 
+    i.* 
+FROM invoice_payments ip JOIN invoices i ON ip.invoice_id = i.id
+WHERE (
+    ip.id >= sqlc.narg('settle_index_get') OR 
+    sqlc.narg('settle_index_get') IS NULL
+) AND (
+    ip.settled_at >= sqlc.narg('settled_after') OR 
+    sqlc.narg('settled_after') IS NULL
+)
+ORDER BY
+    CASE
+        WHEN sqlc.narg('reverse') = FALSE THEN ip.id  
+        ELSE NULL
+    END ASC,
+    CASE
+        WHEN sqlc.narg('reverse') = TRUE THEN ip.id  
+        ELSE NULL
+    END DESC
+LIMIT @num_limit OFFSET @num_offset;
+