package main

import (
	"flag"
	"fmt"
	"os"
	"os/exec"
	"strings"
	"text/template"
	"unicode"
)

func main() {
	var (
		enbasCLISchemaFilepath string
		executorsFilePath      string
	)

	flag.StringVar(&enbasCLISchemaFilepath, "path-to-enbas-cli-schema", "", "The path to the Enbas CLI schema file")
	flag.StringVar(&executorsFilePath, "path-to-enbas-executors", "", "The path to the executors Go file")
	flag.Parse()

	schema, err := newEnbasCLISchemaFromFile(enbasCLISchemaFilepath)
	if err != nil {
		fmt.Printf("ERROR: Unable to read the schema file: %v.\n", err)
	}

	if err := generateExecutors(schema, executorsFilePath); err != nil {
		fmt.Printf("ERROR: Unable to generate the executors: %v.\n", err)
	}

	if err := runGoImports(executorsFilePath); err != nil {
		fmt.Printf("ERROR: Unable to run goimports: %v.\n", err)
	}
}

func generateExecutors(schema enbasCLISchema, output string) error {
	funcMap := template.FuncMap{
		"capitalise":             capitalise,
		"convertFlagToMixedCaps": convertFlagToMixedCaps,
		"getFlagType":            schema.Flags.getType,
		"getFlagDescription":     schema.Flags.getDescription,
	}

	tmpl := template.Must(template.New("executor-template").Funcs(funcMap).Parse(executorsFileTemplate))

	file, err := os.Create(output)
	if err != nil {
		return fmt.Errorf("unable to create the output file: %w", err)
	}
	defer file.Close()

	if err := tmpl.Execute(file, schema.Commands); err != nil {
		return fmt.Errorf("unable to generate the code from the template: %w", err)
	}

	return nil
}

func runGoImports(path string) error {
	imports := exec.Command("goimports", "-w", path)

	if err := imports.Run(); err != nil {
		return fmt.Errorf("received an error after running goimports: %w", err)
	}

	return nil
}

func capitalise(str string) string {
	runes := []rune(str)

	runes[0] = unicode.ToUpper(runes[0])

	return string(runes)
}

func convertFlagToMixedCaps(value string) string {
	var builder strings.Builder

	runes := []rune(value)
	numRunes := len(runes)
	cursor := 0

	for cursor < numRunes {
		if runes[cursor] != '-' {
			builder.WriteRune(runes[cursor])

			cursor++
		} else {
			if cursor != numRunes-1 && unicode.IsLower(runes[cursor+1]) {
				builder.WriteRune(unicode.ToUpper(runes[cursor+1]))
				cursor += 2
			} else {
				cursor++
			}
		}
	}

	return builder.String()
}