feat(catalog/sql): Add views related ops

README.md

@@ -78,10 +78,11 @@ $ cd iceberg-go/cmd/iceberg && go build .
 | Check Namespace Exists      |  X   |      |          |  X   |  X  |
 | Drop Namespace              |  X   |      |          |  X   |  X  |
 | Update Namespace Properties |  X   |      |          |  X   |  X  |
-| Create View                 |  X   |      |          |      |     |
-| List View                   |  X   |      |          |      |     |
-| Drop View                   |  X   |      |          |      |     |
-| Check View Exists           |  X   |      |          |      |     |
+| Create View                 |  X   |      |          |      |  X  |
+| Load View                   |      |      |          |      |  X  |
+| List View                   |  X   |      |          |      |  X  |
+| Drop View                   |  X   |      |          |      |  X  |
+| Check View Exists           |  X   |      |          |      |  X  |
 
 ### Read/Write Data Support
 

catalog/internal/utils.go

@@ -28,6 +28,7 @@ import (
 	"regexp"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/apache/iceberg-go"
 	"github.com/apache/iceberg-go/catalog"
@@ -251,3 +252,160 @@ func UpdateAndStageTable(ctx context.Context, current *table.Table, ident table.
 		),
 	}, nil
 }
+
+func CreateViewMetadata(
+	ctx context.Context,
+	catalogName string,
+	nsIdent []string,
+	schema *iceberg.Schema,
+	viewSQL string,
+	loc string,
+	props iceberg.Properties,
+) (metadataLocation string, err error) {
+	versionId := int64(1)
+	timestampMs := time.Now().UnixMilli()
+
+	viewVersion := struct {
+		VersionID       int64             `json:"version-id"`
+		TimestampMs     int64             `json:"timestamp-ms"`
+		SchemaID        int               `json:"schema-id"`
+		Summary         map[string]string `json:"summary"`
+		Operation       string            `json:"operation"`
+		Representations []struct {
+			Type    string `json:"type"`
+			SQL     string `json:"sql"`
+			Dialect string `json:"dialect"`
+		} `json:"representations"`
+		DefaultCatalog   string   `json:"default-catalog"`
+		DefaultNamespace []string `json:"default-namespace"`
+	}{
+		VersionID:   versionId,
+		TimestampMs: timestampMs,
+		SchemaID:    schema.ID,
+		Summary:     map[string]string{"sql": viewSQL},
+		Operation:   "create",
+		Representations: []struct {
+			Type    string `json:"type"`
+			SQL     string `json:"sql"`
+			Dialect string `json:"dialect"`
+		}{
+			{Type: "sql", SQL: viewSQL, Dialect: "default"},
+		},
+		DefaultCatalog:   catalogName,
+		DefaultNamespace: nsIdent,
+	}
+
+	viewVersionBytes, err := json.Marshal(viewVersion)
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal view version: %w", err)
+	}
+
+	if props == nil {
+		props = iceberg.Properties{}
+	}
+	props["view-version"] = string(viewVersionBytes)
+	props["view-format"] = "iceberg"
+	props["view-sql"] = viewSQL
+
+	metadataLocation = loc + "/metadata/view-" + uuid.New().String() + ".metadata.json"
+
+	viewUUID := uuid.New().String()
+	props["view-uuid"] = viewUUID
+
+	viewMetadata := map[string]interface{}{
+		"view-uuid":          viewUUID,
+		"format-version":     1,
+		"location":           loc,
+		"schema":             schema,
+		"current-version-id": versionId,
+		"versions": map[string]interface{}{
+			"1": viewVersion,
+		},
+		"properties": props,
+		"version-log": []map[string]interface{}{
+			{
+				"timestamp-ms": timestampMs,
+				"version-id":   versionId,
+			},
+		},
+	}
+
+	viewMetadataBytes, err := json.Marshal(viewMetadata)
+	if err != nil {
+		return "", fmt.Errorf("failed to marshal view metadata: %w", err)
+	}
+
+	fs, err := io.LoadFS(ctx, props, metadataLocation)
+	if err != nil {
+		return "", fmt.Errorf("failed to load filesystem for view metadata: %w", err)
+	}
+
+	wfs, ok := fs.(io.WriteFileIO)
+	if !ok {
+		return "", errors.New("filesystem IO does not support writing")
+	}
+
+	out, err := wfs.Create(metadataLocation)
+	if err != nil {
+		return "", fmt.Errorf("failed to create view metadata file: %w", err)
+	}
+	defer out.Close()
+
+	if _, err := out.Write(viewMetadataBytes); err != nil {
+		return "", fmt.Errorf("failed to write view metadata: %w", err)
+	}
+
+	return metadataLocation, nil
+}
+
+func LoadViewMetadata(ctx context.Context,
+	props iceberg.Properties,
+	metadataLocation string,
+	viewName string,
+	namespace string,
+) (map[string]interface{}, error) {
+	// Initial metadata with basic information
+	viewMetadata := map[string]interface{}{
+		"name":              viewName,
+		"namespace":         namespace,
+		"metadata-location": metadataLocation,
+	}
+
+	// Load the filesystem
+	fs, err := io.LoadFS(ctx, props, metadataLocation)
+	if err != nil {
+		return nil, fmt.Errorf("error loading view metadata: %w", err)
+	}
+
+	// Open the metadata file
+	inputFile, err := fs.Open(metadataLocation)
+	if err != nil {
+		return viewMetadata, fmt.Errorf("error encountered loading view metadata: %w", err)
+	}
+	defer inputFile.Close()
+
+	// Decode the complete metadata
+	var fullViewMetadata map[string]interface{}
+	if err := json.NewDecoder(inputFile).Decode(&fullViewMetadata); err != nil {
+		return viewMetadata, fmt.Errorf("error encountered decoding view metadata: %w", err)
+	}
+
+	// Update the metadata with name, namespace and location
+	fullViewMetadata["name"] = viewName
+	fullViewMetadata["namespace"] = namespace
+	fullViewMetadata["metadata-location"] = metadataLocation
+
+	if props, ok := fullViewMetadata["properties"].(map[string]interface{}); ok {
+		strProps := make(map[string]string)
+		for k, v := range props {
+			if str, ok := v.(string); ok {
+				strProps[k] = str
+			} else if vJson, err := json.Marshal(v); err == nil {
+				strProps[k] = string(vJson)
+			}
+		}
+		fullViewMetadata["properties"] = strProps
+	}
+
+	return fullViewMetadata, nil
+}