"use client"

import { memo, useEffect, useLayoutEffect, useRef, useState } from "react"
import { Icon } from "@iconify/react"
import { inboxTabActiveAccentColor } from "@/lib/inbox-category-tabs"
import {
  MAIL_INBOX_CATEGORY_TAB_CONTENT_DARK_CLASS,
} from "@/lib/mail-chrome-classes"
import { inboxTabShowsInactiveMeta } from "@/lib/mail-url"
import { cn } from "@/lib/utils"

export type CompactInboxCategoryTab = {
  id: string
  label: string
  icon: string
  badgeColor: string
}

const TAB_ICON_CLASS = "h-4 w-4 shrink-0"

function inboxTabBadgeDotClass(badgeColor: string) {
  return cn(
    "absolute -right-0.5 -top-0.5 size-2 rounded-full ring-2 ring-mail-surface",
    badgeColor
  )
}

type CompactInboxCategoryTabsProps = {
  tabs: readonly CompactInboxCategoryTab[]
  activeTabId: string
  unseenInTabById: Record<string, number>
  onTabClick: (tabId: string) => void
}

export const CompactInboxCategoryTabs = memo(function CompactInboxCategoryTabs({
  tabs,
  activeTabId,
  unseenInTabById,
  onTabClick,
}: CompactInboxCategoryTabsProps) {
  const barRef = useRef<HTMLDivElement>(null)
  const [indicator, setIndicator] = useState({ x: 0, width: 0, ready: false })
  const [optimisticTabId, setOptimisticTabId] = useState<string | null>(null)
  const displayedTabId = optimisticTabId ?? activeTabId

  useEffect(() => {
    setOptimisticTabId(null)
  }, [activeTabId])

  useLayoutEffect(() => {
    const bar = barRef.current
    if (!bar) return

    let raf = 0
    const measure = () => {
      cancelAnimationFrame(raf)
      raf = requestAnimationFrame(() => {
        const activeBtn = bar.querySelector<HTMLButtonElement>(
          `[data-inbox-tab="${displayedTabId}"]`
        )
        if (!activeBtn) return
        const barRect = bar.getBoundingClientRect()
        const btnRect = activeBtn.getBoundingClientRect()
        const x = btnRect.left - barRect.left
        const width = btnRect.width
        setIndicator((prev) =>
          prev.ready && prev.x === x && prev.width === width
            ? prev
            : { x, width, ready: true }
        )
      })
    }

    measure()

    const onResize = () => measure()
    window.addEventListener("resize", onResize, { passive: true })
    const ro =
      typeof ResizeObserver !== "undefined"
        ? new ResizeObserver(onResize)
        : null
    ro?.observe(bar)

    return () => {
      cancelAnimationFrame(raf)
      window.removeEventListener("resize", onResize)
      ro?.disconnect()
    }
  }, [displayedTabId, tabs])

  const activeTab = tabs.find((t) => t.id === displayedTabId)
  const activeAccentColor = activeTab
    ? inboxTabActiveAccentColor(activeTab.id, activeTab.badgeColor)
    : "#0b57d0"

  return (
    <div ref={barRef} className="relative flex w-full min-w-0">
      <span
        aria-hidden
        className={cn(
          "pointer-events-none absolute bottom-0 left-0 z-[2] h-[3px] origin-left rounded-t-sm",
          "will-change-[transform,width] transition-[transform,width,background-color] duration-300 ease-[cubic-bezier(0.2,0,0,1)] motion-reduce:transition-none",
          indicator.ready ? "opacity-100" : "opacity-0"
        )}
        style={{
          width: indicator.width,
          transform: `translate3d(${indicator.x}px, 0, 0)`,
          backgroundColor: activeAccentColor,
        }}
      />
      {tabs.map((tab) => {
        const isActive = displayedTabId === tab.id
        const accentColor = isActive
          ? inboxTabActiveAccentColor(tab.id, tab.badgeColor)
          : undefined
        const unseen = unseenInTabById[tab.id] ?? 0
        const showMeta =
          inboxTabShowsInactiveMeta(tab.id) && !isActive && unseen > 0

        return (
          <button
            key={tab.id}
            type="button"
            data-inbox-tab={tab.id}
            title={!isActive ? tab.label : undefined}
            aria-label={tab.label}
            aria-current={isActive ? "true" : undefined}
            onClick={() => {
              if (tab.id !== activeTabId) setOptimisticTabId(tab.id)
              onTabClick(tab.id)
            }}
            className={cn(
              "relative z-[1] flex min-h-10 cursor-pointer items-center justify-center px-1",
              "transition-colors duration-200 motion-reduce:transition-none",
              isActive ? "shrink-0 flex-none" : "min-w-0 flex-1 overflow-hidden",
              !isActive && "hover:bg-mail-nav-hover"
            )}
          >
            <div
              className={cn(
                "flex h-10 items-center justify-center gap-1.5",
                isActive ? "shrink-0 px-0.5" : "w-full min-w-0"
              )}
            >
              <div className="relative inline-flex shrink-0">
                <Icon
                  icon={tab.icon}
                  className={cn(
                    TAB_ICON_CLASS,
                    "transition-colors duration-200 motion-reduce:transition-none",
                    MAIL_INBOX_CATEGORY_TAB_CONTENT_DARK_CLASS,
                    !isActive && "text-muted-foreground"
                  )}
                  style={accentColor ? { color: accentColor } : undefined}
                  aria-hidden
                />
                {showMeta && unseen > 0 ? (
                  <span
                    className={inboxTabBadgeDotClass(tab.badgeColor)}
                    aria-hidden
                  />
                ) : null}
              </div>
              {isActive ? (
                <span
                  className={cn(
                    "shrink-0 whitespace-nowrap text-[13px] font-semibold leading-tight",
                    MAIL_INBOX_CATEGORY_TAB_CONTENT_DARK_CLASS,
                    accentColor ? undefined : "text-foreground"
                  )}
                  style={accentColor ? { color: accentColor } : undefined}
                >
                  {tab.label}
                </span>
              ) : null}
            </div>
          </button>
        )
      })}
    </div>
  )
})