type MonoFont = {
  id: string
  family: string
  regular: string
  bold: string
}

let files: Record<string, () => Promise<string>> | undefined

function getFiles() {
  if (files) return files
  files = import.meta.glob("./assets/fonts/*.woff2", { import: "default" }) as Record<string, () => Promise<string>>
  return files
}

export const MONO_NERD_FONTS = [
  {
    id: "jetbrains-mono",
    family: "JetBrains Mono Nerd Font",
    regular: "./assets/fonts/jetbrains-mono-nerd-font.woff2",
    bold: "./assets/fonts/jetbrains-mono-nerd-font-bold.woff2",
  },
  {
    id: "fira-code",
    family: "Fira Code Nerd Font",
    regular: "./assets/fonts/fira-code-nerd-font.woff2",
    bold: "./assets/fonts/fira-code-nerd-font-bold.woff2",
  },
  {
    id: "cascadia-code",
    family: "Cascadia Code Nerd Font",
    regular: "./assets/fonts/cascadia-code-nerd-font.woff2",
    bold: "./assets/fonts/cascadia-code-nerd-font-bold.woff2",
  },
  {
    id: "hack",
    family: "Hack Nerd Font",
    regular: "./assets/fonts/hack-nerd-font.woff2",
    bold: "./assets/fonts/hack-nerd-font-bold.woff2",
  },
  {
    id: "source-code-pro",
    family: "Source Code Pro Nerd Font",
    regular: "./assets/fonts/source-code-pro-nerd-font.woff2",
    bold: "./assets/fonts/source-code-pro-nerd-font-bold.woff2",
  },
  {
    id: "inconsolata",
    family: "Inconsolata Nerd Font",
    regular: "./assets/fonts/inconsolata-nerd-font.woff2",
    bold: "./assets/fonts/inconsolata-nerd-font-bold.woff2",
  },
  {
    id: "roboto-mono",
    family: "Roboto Mono Nerd Font",
    regular: "./assets/fonts/roboto-mono-nerd-font.woff2",
    bold: "./assets/fonts/roboto-mono-nerd-font-bold.woff2",
  },
  {
    id: "ubuntu-mono",
    family: "Ubuntu Mono Nerd Font",
    regular: "./assets/fonts/ubuntu-mono-nerd-font.woff2",
    bold: "./assets/fonts/ubuntu-mono-nerd-font-bold.woff2",
  },
  {
    id: "intel-one-mono",
    family: "Intel One Mono Nerd Font",
    regular: "./assets/fonts/intel-one-mono-nerd-font.woff2",
    bold: "./assets/fonts/intel-one-mono-nerd-font-bold.woff2",
  },
  {
    id: "meslo-lgs",
    family: "Meslo LGS Nerd Font",
    regular: "./assets/fonts/meslo-lgs-nerd-font.woff2",
    bold: "./assets/fonts/meslo-lgs-nerd-font-bold.woff2",
  },
  {
    id: "iosevka",
    family: "Iosevka Nerd Font",
    regular: "./assets/fonts/iosevka-nerd-font.woff2",
    bold: "./assets/fonts/iosevka-nerd-font-bold.woff2",
  },
  {
    id: "geist-mono",
    family: "GeistMono Nerd Font",
    regular: "./assets/fonts/GeistMonoNerdFontMono-Regular.woff2",
    bold: "./assets/fonts/GeistMonoNerdFontMono-Bold.woff2",
  },
] satisfies MonoFont[]

const mono = Object.fromEntries(MONO_NERD_FONTS.map((font) => [font.id, font])) as Record<string, MonoFont>
const loads = new Map<string, Promise<void>>()

function css(font: { family: string; regular: string; bold: string }) {
  return `
    @font-face {
      font-family: "${font.family}";
      src: url("${font.regular}") format("woff2");
      font-display: swap;
      font-style: normal;
      font-weight: 400;
    }
    @font-face {
      font-family: "${font.family}";
      src: url("${font.bold}") format("woff2");
      font-display: swap;
      font-style: normal;
      font-weight: 700;
    }
  `
}

export function ensureMonoFont(id: string | undefined) {
  if (!id || id === "ibm-plex-mono") return Promise.resolve()
  if (typeof document !== "object") return Promise.resolve()
  const font = mono[id]
  if (!font) return Promise.resolve()
  const styleId = `oc-font-${font.id}`
  if (document.getElementById(styleId)) return Promise.resolve()
  const hit = loads.get(font.id)
  if (hit) return hit
  const files = getFiles()
  const load = Promise.all([files[font.regular]?.(), files[font.bold]?.()]).then(([regular, bold]) => {
    if (!regular || !bold) return
    if (document.getElementById(styleId)) return
    const style = document.createElement("style")
    style.id = styleId
    style.textContent = css({ family: font.family, regular, bold })
    document.head.appendChild(style)
  })
  loads.set(font.id, load)
  return load
}