package web

import (
	"embed"
	"fmt"
	"html/template"
	"time"
)

//go:embed templates/*.html templates/fragments/*.html
var templateFS embed.FS

type templateSet struct {
	dashboard     *template.Template
	sessionDetail *template.Template
}

func templateFuncMap() template.FuncMap {
	return template.FuncMap{
		"formatTime": func(t time.Time) string {
			return t.Format("2006-01-02 15:04:05 UTC")
		},
		"truncateID": func(id string) string {
			if len(id) > 8 {
				return id[:8]
			}
			return id
		},
		"derefTime": func(t *time.Time) time.Time {
			if t == nil {
				return time.Time{}
			}
			return *t
		},
		"derefFloat": func(f *float64) float64 {
			if f == nil {
				return 0
			}
			return *f
		},
		"formatScore": func(f *float64) string {
			if f == nil {
				return "-"
			}
			return fmt.Sprintf("%.0f%%", *f*100)
		},
		"derefString": func(s *string) string {
			if s == nil {
				return ""
			}
			return *s
		},
		"truncateCommand": func(s string) string {
			if len(s) > 50 {
				return s[:50] + "..."
			}
			return s
		},
		"formatBytes": func(b int64) string {
			const (
				kb = 1024
				mb = 1024 * kb
			)
			switch {
			case b >= mb:
				return fmt.Sprintf("%.1f MB", float64(b)/float64(mb))
			case b >= kb:
				return fmt.Sprintf("%.1f KB", float64(b)/float64(kb))
			default:
				return fmt.Sprintf("%d B", b)
			}
		},
	}
}

func loadTemplates() (*templateSet, error) {
	funcMap := templateFuncMap()

	dashboard, err := template.New("").Funcs(funcMap).ParseFS(templateFS,
		"templates/layout.html",
		"templates/dashboard.html",
		"templates/fragments/stats.html",
		"templates/fragments/active_sessions.html",
		"templates/fragments/recent_sessions.html",
	)
	if err != nil {
		return nil, fmt.Errorf("parsing dashboard templates: %w", err)
	}

	sessionDetail, err := template.New("").Funcs(funcMap).ParseFS(templateFS,
		"templates/layout.html",
		"templates/session_detail.html",
	)
	if err != nil {
		return nil, fmt.Errorf("parsing session detail templates: %w", err)
	}

	return &templateSet{
		dashboard:     dashboard,
		sessionDetail: sessionDetail,
	}, nil
}