init post-service

services/post-service/internal/post.go

@@ -0,0 +1,162 @@
+package internal
+
+import (
+	"regexp"
+	"context"
+	"strconv"
+	"encoding/json"
+	"database/sql"
+	"database/sql/driver"
+	
+	"github.com/jackc/pgx/v5/pgtype"
+	"github.com/go-ozzo/ozzo-validation/v4"
+)
+
+// Post Models
+type Post struct {
+	Id PostId `json:"id"`
+
+	PanelId string `json:"panel_id"`
+	AuthorId string `json:"author_id"`
+
+	Title string `json:"title"`
+	Content string `json:"content"`
+	
+	CreatedAt pgtype.Timestamp `json:"created_at"`
+	UpdatedAt pgtype.Timestamp `json:"updated_at"`
+}
+
+type PostCreate struct {
+	Title string `json:"title"`
+	Content string `json:"content"`
+}
+
+func (p *PostCreate) Validate() error {
+	return validation.ValidateStruct(
+		p,
+		validation.Field(&p.Title, validation.Required, validation.Length(3, 512), validation.Match(regexp.MustCompile("^[^_][\\w ]+[^_]$"))),
+		validation.Field(&p.Content, validation.Required, validation.Length(3, 2048)),
+	)
+}
+
+type PostUpdate struct {
+	Title *string `json:"title,omitempty"`
+	Content *string `json:"content,omitempty"`
+}
+
+func (p *PostUpdate) Validate() error {
+	return validation.ValidateStruct(
+		p,
+		validation.Field(&p.Title, validation.NilOrNotEmpty, validation.Length(3, 512), validation.Match(regexp.MustCompile("^[^_][\\w ]+[^_]$"))),
+		validation.Field(&p.Content, validation.NilOrNotEmpty, validation.Length(3, 2048)),
+	)
+}
+
+// Service Interface Methods
+type PostService interface {
+	PostRepository
+}
+
+type PostRepository interface {
+    CreatePost(ctx context.Context, panelId string, authorId string, data PostCreate) (*Post, error)
+    GetPost(ctx context.Context, id PostId) (*Post, error)
+    GetPanelPost(ctx context.Context, id PostId, panelId string) (*Post, error)
+    UpdatePost(ctx context.Context, id PostId, data PostUpdate) (*Post, error)
+    DeletePost(ctx context.Context, id PostId) error
+
+    GetFeedPosts(ctx context.Context) ([]*Post, error)
+    GetUserPosts(ctx context.Context, userId string) ([]*Post, error)
+    GetPanelPosts(ctx context.Context, panelId string) ([]*Post, error)
+}
+
+type PostDBRepository interface {
+	PostRepository
+
+	DeletePostsByUser(ctx context.Context, userId string) ([]PostId, error)
+	DeletePostsOnPanel(ctx context.Context, panelId string) ([]PostId, error)
+}
+
+// Converts IDs between int64 (base 10) internally and string (base 36) externally
+type PostId struct {
+	Id int64
+}
+
+func (pid *PostId) GetId() int64 {
+	if pid == nil {
+		return 0
+	}
+	return pid.Id
+}
+
+func (pid *PostId) GetReprId() string {
+	if pid.GetId() == 0 {
+		return ""
+	}
+
+	return strconv.FormatInt(pid.GetId(), 36)
+}
+
+func (pid *PostId) Scan(value interface{}) error {
+	scnr := sql.NullInt64{}
+	err := scnr.Scan(value)
+	if err != nil {
+		return NewServiceError(InvalidArgumentErrorCode, "failed to scan post id: must be of type int64")
+	} else if scnr.Int64 < 1 {
+		return NewServiceError(InvalidArgumentErrorCode, "invalid post id: value must be greater than 0")
+	}
+
+	pid.Id = scnr.Int64
+	return nil
+}
+
+func (pid PostId) Value() (driver.Value, error) {
+	if pid.GetId() == 0 {
+		return nil, NewServiceError(InvalidArgumentErrorCode, "post id not provided (of default value)")
+	}
+
+	return driver.Value(pid.GetId()), nil
+}
+
+func (pid PostId) MarshalJSON() ([]byte, error) {
+	return json.Marshal(pid.GetReprId())
+}
+
+func (pid *PostId) UnmarshalJSON(data []byte) error {
+	// Attempt to unmarshal the representative id
+	var repr_id string
+	err := json.Unmarshal(data, &repr_id)
+	if err != nil {
+		return err
+	}
+
+	// Reconstruct the ID using the representative ID
+	id, err := getIdFromRepr(repr_id)
+	if err != nil {
+		return err
+	}
+
+	pid.Id = *id
+	return nil
+}
+
+func NewPostId(id int64) (*PostId, error) {
+	if id < 1 {
+		return nil, NewServiceError(InvalidArgumentErrorCode, "invalid post id: value must be greater than 0")
+	}
+
+	return &PostId{Id: id}, nil
+}
+
+func NewPostIdFromRepr(reprId string) (*PostId, error) {
+	id, err := getIdFromRepr(reprId)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewPostId(*id)
+}
+
+func getIdFromRepr(reprId string) (*int64, error) {
+	id, err := strconv.ParseInt(reprId, 36, 64)
+	return &id, err
+}