tsk-12: Added endpoint to get message (#18)

Closes #12

Reviewed-on: phoenix/textsender-api#18
Co-authored-by: phoenix <kundeng00@pm.me>
Co-committed-by: phoenix <kundeng00@pm.me>

internal/store/message_store.go

@@ -4,13 +4,17 @@ import (
 	"context"
 	"fmt"
 
+	"github.com/google/uuid"
+	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
 
 	"git.kundeng.us/phoenix/textsender-models/pkg/message"
 )
 
 type MessageStore interface {
+	GetMessageByID(ctx context.Context, id uuid.UUID) (*message.Message, error)
 	CreateMessage(ctx context.Context, msg *message.Message) error
+	GetAllMessages(ctx context.Context) ([]*message.Message, error)
 	MessageExists(ctx context.Context, msg *message.Message) (bool, error)
 }
 
@@ -45,3 +49,48 @@ func (m *PGMessageStore) MessageExists(ctx context.Context, msg *message.Message
 		return exists, nil
 	}
 }
+
+func (m *PGMessageStore) GetAllMessages(ctx context.Context) ([]*message.Message, error) {
+	query := `SELECT id, content, user_id FROM messages`
+
+	rows, err := m.db.Query(ctx, query)
+	if err != nil {
+		return nil, fmt.Errorf("querying all messages: %w", err)
+	}
+	defer rows.Close()
+
+	var messages []*message.Message
+	for rows.Next() {
+		var msg message.Message
+		if err := rows.Scan(
+			&msg.Id, &msg.Content, &msg.UserId,
+		); err != nil {
+			return nil, fmt.Errorf("scanning message row: %w", err)
+		}
+		messages = append(messages, &msg)
+	}
+
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("iterating message rows: %w", err)
+	}
+
+	return messages, nil
+}
+
+func (m *PGMessageStore) GetMessageByID(ctx context.Context, id uuid.UUID) (*message.Message, error) {
+	query := `SELECT id, content, user_id FROM messages WHERE id = $1`
+
+	var msg message.Message
+	err := m.db.QueryRow(ctx, query, id).Scan(
+		&msg.Id, &msg.Content, &msg.UserId,
+	)
+
+	if err == pgx.ErrNoRows {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, fmt.Errorf("getting message by ID: %w", err)
+	}
+
+	return &msg, nil
+}