package web

import (
	"net/http"
	"strings"
)

// themeCookieName is the cookie projax uses to persist the user's chosen
// theme. Read by the layout on render, written by the inline toggle script
// in the header nav. Not HttpOnly because the toggle is JS-driven; a
// compromise here at worst flips someone's colour scheme.
const themeCookieName = "projax_theme"

const (
	themeDark  = "dark"
	themeLight = "light"
)

// themeFromRequest reads the projax_theme cookie. Unknown / missing values
// fall back to the default (dark). Whitespace + case are normalised so a
// hand-typed cookie still works.
func themeFromRequest(r *http.Request) string {
	if r == nil {
		return themeDark
	}
	c, err := r.Cookie(themeCookieName)
	if err != nil {
		return themeDark
	}
	v := strings.ToLower(strings.TrimSpace(c.Value))
	switch v {
	case themeLight:
		return themeLight
	case themeDark:
		return themeDark
	}
	return themeDark
}

// themeColorForMeta returns the colour value for the `<meta name="theme-color">`
// tag. Apple Safari uses this to tint the iOS status bar in the installed PWA.
func themeColorForMeta(theme string) string {
	if theme == themeLight {
		return "#f0efe8"
	}
	return "#161616"
}