package system

import (
	"context"
	"os"
	"path/filepath"
	"strings"
	"text/template"
	"unicode"

	systemReq "git.echol.cn/loser/Go-Web-Template/server/model/system/request"
)

type McpService struct{}

func (s *McpService) CreateToolTemplate(_ context.Context, info systemReq.McpToolTemplateRequest) (string, error) {
	serverRoot := resolveServiceServerRoot()
	templatePath := filepath.Join(serverRoot, "resource", "mcp", "tools.tpl")
	targetDir := filepath.Join(serverRoot, "mcp")

	files, err := template.New(filepath.Base(templatePath)).Funcs(template.FuncMap{
		"title": toToolStructName,
	}).ParseFiles(templatePath)
	if err != nil {
		return "", err
	}

	fileName := toToolFileName(info.Name)
	targetPath := filepath.Join(targetDir, fileName+".go")

	f, err := os.Create(targetPath)
	if err != nil {
		return "", err
	}
	defer f.Close()

	if err := files.Execute(f, info); err != nil {
		return "", err
	}

	return targetPath, nil
}

func resolveServiceServerRoot() string {
	if cwd, err := os.Getwd(); err == nil {
		if filepath.Base(cwd) == "server" {
			return cwd
		}
		if _, err := os.Stat(filepath.Join(cwd, "server")); err == nil {
			return filepath.Join(cwd, "server")
		}
		return cwd
	}
	return "server"
}

func toToolFileName(name string) string {
	var b strings.Builder
	for index, r := range name {
		if unicode.IsUpper(r) {
			if index > 0 {
				b.WriteByte('_')
			}
			b.WriteRune(unicode.ToLower(r))
			continue
		}
		if unicode.IsLetter(r) || unicode.IsDigit(r) || r == '_' {
			b.WriteRune(unicode.ToLower(r))
			continue
		}
		b.WriteByte('_')
	}
	return strings.Trim(b.String(), "_")
}

func toToolStructName(name string) string {
	parts := strings.FieldsFunc(name, func(r rune) bool {
		return !(unicode.IsLetter(r) || unicode.IsDigit(r))
	})
	var b strings.Builder
	for _, part := range parts {
		if part == "" {
			continue
		}
		runes := []rune(strings.ToLower(part))
		runes[0] = unicode.ToUpper(runes[0])
		b.WriteString(string(runes))
	}
	if b.Len() == 0 {
		return "CustomTool"
	}
	return b.String()
}