package main

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"strings"
	"text/template"

	"golang.org/x/text/cases"
	"golang.org/x/text/language"
	"gopkg.in/yaml.v3"
)

type ErrorItem struct {
	Name  string
	Value string
}

type TplData struct {
	Items []ErrorItem
}

func toCamel(s string) string {
	caser := cases.Title(language.English)
	s = strings.ReplaceAll(s, "-", "_")
	parts := strings.Split(s, "_")
	for i := range parts {
		parts[i] = caser.String(parts[i])
	}
	return strings.Join(parts, "")
}

func recursiveParse(prefix string, raw any, items *[]ErrorItem) {
	switch v := raw.(type) {
	case map[string]any:
		for key, val := range v {
			recursiveParse(prefix+toCamel(key), val, items)
		}
	case string:
		*items = append(*items, ErrorItem{
			Name:  prefix,
			Value: v,
		})
	case int, int64:
		*items = append(*items, ErrorItem{
			Name:  prefix,
			Value: fmt.Sprintf("%v", v),
		})
	}
}

func main() {
	yamlDir := "cmd/gen_exception/definitions"
	outputDir := "internal/exception"
	tplPath := "cmd/gen_exception/exception.tmpl"

	if _, err := os.Stat(tplPath); os.IsNotExist(err) {
		log.Fatalf("Cannot found tmpl %s", tplPath)
	}

	funcMap := template.FuncMap{"ToCamel": toCamel}
	tmpl := template.Must(template.New("exception.tmpl").Funcs(funcMap).ParseFiles(tplPath))

	os.MkdirAll(outputDir, 0755)

	files, _ := filepath.Glob(filepath.Join(yamlDir, "*.yaml"))
	for _, yamlFile := range files {
		content, err := os.ReadFile(yamlFile)
		if err != nil {
			log.Printf("Read file error: %v", err)
			continue
		}

		var rawData any
		if err := yaml.Unmarshal(content, &rawData); err != nil {
			log.Printf("Unmarshal error in %s: %v", yamlFile, err)
			continue
		}

		var items []ErrorItem
		recursiveParse("", rawData, &items)

		baseName := strings.TrimSuffix(filepath.Base(yamlFile), filepath.Ext(yamlFile))
		outputFileName := baseName + "_gen.go"
		outputPath := filepath.Join(outputDir, outputFileName)

		f, _ := os.Create(outputPath)
		tmpl.Execute(f, TplData{Items: items})
		f.Close()

		fmt.Printf("Generated: %s (%d constants)\n", outputPath, len(items))
	}
}