Add convert command and tweak .gitignore

.gitignore

@@ -7,7 +7,7 @@
 *.dll
 *.so
 *.dylib
-datakeg
+/datakeg
 
 # Test binary, built with `go test -c`
 *.test

cmd/datakeg/commands/convert.go

@@ -0,0 +1,100 @@
+package commands
+
+import (
+	"fmt"
+	"text/template"
+
+	"github.com/danmurf/datakeg/internal/converter"
+	"github.com/danmurf/datakeg/internal/generator"
+	"github.com/danmurf/datakeg/internal/templates"
+)
+
+// ExecuteConvertPipeline orchestrates the JSONL format conversion pipeline.
+// It loads a template, detects or validates the source format, validates the template
+// compatibility, and then performs the conversion.
+func ExecuteConvertPipeline(inputPath, outputPath, templateName, customTemplatePath, sourceFormat string) error {
+	fmt.Printf("Converting %s...\n", inputPath)
+
+	// Load template (built-in or custom)
+	var tmpl *template.Template
+	var err error
+	if customTemplatePath != "" {
+		tmpl, err = templates.LoadCustomConversionTemplate(customTemplatePath)
+		if err != nil {
+			return fmt.Errorf("load custom template: %w", err)
+		}
+		fmt.Printf("Using custom template: %s\n", customTemplatePath)
+	} else {
+		tmpl, err = templates.LoadConversionTemplate(templateName)
+		if err != nil {
+			return fmt.Errorf("load template '%s': %w. Run 'datakeg convert --list-templates' to see available templates", templateName, err)
+		}
+		fmt.Printf("Using built-in template: %s\n", templateName)
+	}
+
+	// Detect or parse source format
+	var format generator.FormatType
+	if sourceFormat != "" {
+		format, err = generator.ParseFormat(sourceFormat)
+		if err != nil {
+			return err
+		}
+		fmt.Printf("Source format: %s (specified)\n", format)
+	} else {
+		format, err = converter.DetectFormatFromFile(inputPath)
+		if err != nil {
+			return fmt.Errorf("could not detect source format: %w. Specify --source-format explicitly", err)
+		}
+		fmt.Printf("Detected source format: %s\n", format)
+	}
+
+	// Validate template compatibility
+	if err := converter.ValidateTemplate(tmpl, format); err != nil {
+		return fmt.Errorf("template validation failed: %w", err)
+	}
+
+	// Convert
+	linesConverted, err := converter.ConvertJSONL(inputPath, outputPath, tmpl, format)
+	if err != nil {
+		return fmt.Errorf("conversion failed: %w", err)
+	}
+
+	fmt.Printf("Conversion complete: %s (%d lines converted)\n", outputPath, linesConverted)
+	return nil
+}
+
+// ListBuiltinTemplates prints the available built-in conversion templates with descriptions.
+func ListBuiltinTemplates() error {
+	templateNames, err := templates.ListConversionTemplates()
+	if err != nil {
+		return fmt.Errorf("list templates: %w", err)
+	}
+
+	type templateInfo struct {
+		format string
+		desc   string
+	}
+	info := map[string]templateInfo{
+		"mistral-instruct": {"completion", "Mistral Instruct format with [INST] tags"},
+		"llama3-instruct":  {"chat", "Llama 3 Instruct with header tags"},
+		"chatml":           {"chat", "ChatML format with <|im_start|> tags"},
+		"deepseek-r1":      {"reasoning", "DeepSeek-R1 integrated reasoning format"},
+	}
+
+	fmt.Println("Built-in conversion templates:")
+	fmt.Println()
+
+	for _, name := range templateNames {
+		if ti, ok := info[name]; ok {
+			fmt.Printf("  %-20s (%-10s) - %s\n", name, ti.format, ti.desc)
+		} else {
+			fmt.Printf("  %-20s                   - (no description)\n", name)
+		}
+	}
+
+	fmt.Println()
+	fmt.Println("Usage: datakeg convert --template <name> <input.jsonl> <output.jsonl>")
+	fmt.Println("Custom: datakeg convert --custom-template <file.tmpl> <input.jsonl> <output.jsonl>")
+
+	return nil
+}