first commit

cmd/parse.go

@@ -0,0 +1,139 @@
+// Patial Tech.
+// Author, Ankit Patial
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+type (
+	TableInfo struct {
+		Schema     string
+		Table      string
+		Columns    []*Column
+		PrimaryKey []string
+	}
+
+	Column struct {
+		// Name of column
+		Name string
+		// Type of column
+		Type string
+	}
+)
+
+func parse(scheam []byte) ([]*TableInfo, error) {
+	var (
+		t      = false
+		n      = bytes.Count(scheam, []byte("CREATE TABLE"))
+		tables = make([]*TableInfo, n)
+		i      = 0
+		sb     strings.Builder
+	)
+
+	for l := range bytes.SplitSeq(scheam, []byte("\n")) {
+		if strings.HasPrefix(string(l), "CREATE TABLE") {
+			t = true
+			sb.Write(l)
+		} else if t {
+			sb.Write(l)
+			if strings.Contains(string(l), ";") {
+				t = false
+				t, err := parseTableStmt(sb.String())
+				if err != nil {
+					return nil, err
+				}
+				tables[i] = t
+				i++
+				sb.Reset()
+			}
+
+		}
+	}
+
+	return tables, nil
+}
+
+func parseTableStmt(sqlStatement string) (*TableInfo, error) {
+	// Regex to match CREATE TABLE statement and extract table name and column definitions
+	tableRegex := regexp.MustCompile(`(?i)CREATE\s+TABLE\s+(?:IF\s+NOT\s+EXISTS\s+)?(?:` + "`" + `?(\w+)` + "`" + `?\.)?` + "`" + `?(\w+)` + "`" + `?\s*\(([\s\S]*?)\)(?:\s*ENGINE.*?)?;`)
+	matches := tableRegex.FindStringSubmatch(sqlStatement)
+	if matches == nil {
+		return nil, fmt.Errorf("no CREATE TABLE statement found")
+	}
+
+	schema := matches[1]
+	tbl := matches[2]
+	cols := matches[3]
+
+	// Parse column definitions by splitting first on commas
+	// This is a simplistic approach - a real SQL parser would be more robust
+	columns := parseColumns(cols)
+
+	return &TableInfo{
+		Schema:  schema,
+		Table:   tbl,
+		Columns: columns,
+	}, nil
+}
+
+func parseColumns(colsStr string) []*Column {
+	var columns []*Column
+	var currentDef strings.Builder
+	parenthesesCount := 0
+	inQuote := false
+
+	// First, intelligently split the column definitions
+	var columnDefs []string
+	for _, char := range colsStr {
+		if char == '(' {
+			parenthesesCount++
+			currentDef.WriteRune(char)
+		} else if char == ')' {
+			parenthesesCount--
+			currentDef.WriteRune(char)
+		} else if char == '\'' || char == '"' {
+			inQuote = !inQuote
+			currentDef.WriteRune(char)
+		} else if char == ',' && parenthesesCount == 0 && !inQuote {
+			// End of a column definition
+			columnDefs = append(columnDefs, strings.TrimSpace(currentDef.String()))
+			currentDef.Reset()
+		} else {
+			currentDef.WriteRune(char)
+		}
+	}
+
+	// Add the last column definition if there's anything left
+	if currentDef.Len() > 0 {
+		columnDefs = append(columnDefs, strings.TrimSpace(currentDef.String()))
+	}
+
+	// Now parse each column definition
+	for _, colDef := range columnDefs {
+		// Skip constraints and keys that don't define columns
+		if strings.HasPrefix(strings.ToUpper(colDef), "PRIMARY KEY") ||
+			strings.HasPrefix(strings.ToUpper(colDef), "UNIQUE KEY") ||
+			strings.HasPrefix(strings.ToUpper(colDef), "FOREIGN KEY") ||
+			strings.HasPrefix(strings.ToUpper(colDef), "KEY") ||
+			strings.HasPrefix(strings.ToUpper(colDef), "INDEX") ||
+			strings.HasPrefix(strings.ToUpper(colDef), "CONSTRAINT") {
+			continue
+		}
+
+		colNameRegex := regexp.MustCompile(`^` + "`" + `?(\w+)` + "`" + `?\s+(.+)$`)
+		matches := colNameRegex.FindStringSubmatch(colDef)
+		if matches != nil {
+			columns = append(columns, &Column{
+				Name: matches[1],
+				Type: strings.TrimSpace(matches[2]),
+			})
+		}
+	}
+
+	return columns
+}