Add "query database" endpoint

page.go

@@ -0,0 +1,95 @@
+package notion
+
+import (
+	"encoding/json"
+	"fmt"
+	"time"
+)
+
+// Page is a resource on the Notion platform. Its parent is either a workspace,
+// another page, or a database.
+// See: https://developers.notion.com/reference/page
+type Page struct {
+	ID             string     `json:"id"`
+	CreatedTime    time.Time  `json:"created_time"`
+	LastEditedTime time.Time  `json:"last_edited_time"`
+	Parent         PageParent `json:"parent"`
+	Archived       bool       `json:"archived"`
+
+	// Properties differ between parent type.
+	// See the `UnmarshalJSON` method.
+	Properties interface{} `json:"properties"`
+}
+
+type PageParent struct {
+	Type string `json:"type"`
+
+	PageID     *string `json:"page_id"`
+	DatabaseID *string `json:"database_id"`
+}
+
+// PageProperties are properties of a page whose parent is a page or a workspace.
+type PageProperties struct {
+	Title struct {
+		Title []RichText `json:"title"`
+	} `json:"title"`
+}
+
+// DatabasePageProperties are properties of a page whose parent is a database.
+type DatabasePageProperties map[string]DatabasePageProperty
+
+type DatabasePageProperty struct {
+	DatabaseProperty
+	RichText    []RichText       `json:"rich_text"`
+	Select      *SelectMetadata  `json:"select"`
+	MultiSelect []SelectMetadata `json:"multi_select"`
+}
+
+// UnmarshalJSON implements json.Unmarshaler.
+//
+// Pages get a different Properties type based on the parent of the page.
+// If parent type is `workspace` or `page_id`, PageProperties is used. Else if
+// parent type is `database_id`, DatabasePageProperties is used.
+func (p *Page) UnmarshalJSON(b []byte) error {
+	type (
+		PageAlias Page
+		PageDTO   struct {
+			PageAlias
+			Properties json.RawMessage `json:"properties"`
+		}
+	)
+
+	var dto PageDTO
+
+	err := json.Unmarshal(b, &dto)
+	if err != nil {
+		return err
+	}
+
+	page := dto.PageAlias
+
+	switch dto.Parent.Type {
+	case "workspace":
+		fallthrough
+	case "page_id":
+		var props PageProperties
+		err := json.Unmarshal(dto.Properties, &props)
+		if err != nil {
+			return err
+		}
+		page.Properties = props
+	case "database_id":
+		var props DatabasePageProperties
+		err := json.Unmarshal(dto.Properties, &props)
+		if err != nil {
+			return err
+		}
+		page.Properties = props
+	default:
+		return fmt.Errorf("unknown page parent type %q", dto.Parent.Type)
+	}
+
+	*p = Page(page)
+
+	return nil
+}