Move IP country block SQL to coredata

Extract struct and query functions into
pkg/coredata/ip_country_block.go following the convention that
all raw SQL lives in coredata. The geoloc service now delegates
to these functions.

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/coredata/ip_country_block.go

@@ -0,0 +1,98 @@
+// Copyright (c) 2026 Probo Inc <hello@getprobo.com>.
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+// PERFORMANCE OF THIS SOFTWARE.
+
+package coredata
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/jackc/pgx/v5"
+	"go.gearno.de/kit/pg"
+)
+
+type IPCountryBlock struct {
+	CIDR        string      `db:"cidr"`
+	CountryCode CountryCode `db:"country_code"`
+}
+
+func LookupCountryByIP(ctx context.Context, conn pg.Querier, ip string) (CountryCode, error) {
+	q := `
+SELECT country_code
+FROM common_ip_country_blocks
+WHERE cidr >>= @ip::inet
+ORDER BY masklen(cidr) DESC
+LIMIT 1;
+`
+
+	args := pgx.StrictNamedArgs{"ip": ip}
+
+	rows, err := conn.Query(ctx, q, args)
+	if err != nil {
+		return "", fmt.Errorf("cannot query ip country blocks: %w", err)
+	}
+
+	cc, err := pgx.CollectExactlyOneRow(rows, pgx.RowTo[CountryCode])
+	if err != nil {
+		if err == pgx.ErrNoRows {
+			return "", nil
+		}
+		return "", fmt.Errorf("cannot collect ip country block row: %w", err)
+	}
+
+	return cc, nil
+}
+
+func IsIPCountryBlocksPopulated(ctx context.Context, conn pg.Querier) (bool, error) {
+	q := `SELECT EXISTS (SELECT 1 FROM common_ip_country_blocks);`
+
+	rows, err := conn.Query(ctx, q)
+	if err != nil {
+		return false, fmt.Errorf("cannot check if ip country blocks is populated: %w", err)
+	}
+
+	populated, err := pgx.CollectExactlyOneRow(rows, pgx.RowTo[bool])
+	if err != nil {
+		return false, fmt.Errorf("cannot collect populated check: %w", err)
+	}
+
+	return populated, nil
+}
+
+func TruncateIPCountryBlocks(ctx context.Context, conn pg.Querier) error {
+	_, err := conn.Exec(ctx, "TRUNCATE common_ip_country_blocks")
+	if err != nil {
+		return fmt.Errorf("cannot truncate common_ip_country_blocks: %w", err)
+	}
+	return nil
+}
+
+func CopyIPCountryBlocks(ctx context.Context, conn pg.Querier, blocks []IPCountryBlock) error {
+	rows := make([][]any, len(blocks))
+	for i, b := range blocks {
+		rows[i] = []any{b.CIDR, b.CountryCode.String()}
+	}
+
+	_, err := conn.CopyFrom(
+		ctx,
+		pgx.Identifier{"common_ip_country_blocks"},
+		[]string{"cidr", "country_code"},
+		pgx.CopyFromRows(rows),
+	)
+	if err != nil {
+		return fmt.Errorf("cannot copy rows into common_ip_country_blocks: %w", err)
+	}
+
+	return nil
+}