import { useState } from 'react'
import type { TimeRange, TimeRangePresetId } from '../lib/timeRange'

/// Shared look for a primary section's title bar: shaded so it reads as a
/// distinct band rather than blending into the section body below it.
/// The bar itself is the collapse/expand click target (see `sectionHeaderInteractiveClassName`) —
/// this className alone (no click handling) is for the rare header that stays static.
export const sectionHeaderClassName =
  'flex items-center justify-between gap-2 border-b border-border-soft bg-surface-1 px-3 py-1.5'

/// `sectionHeaderClassName` plus the affordance for a header row that toggles collapse on click:
/// pointer cursor and a hover tint so the whole bar reads as clickable, not just the chevron.
export const sectionHeaderInteractiveClassName = `${sectionHeaderClassName} cursor-pointer select-none hover:bg-surface-2`

/// Left-hand cluster of a section header: title text, help icon, collapse/pop-out controls.
export const sectionHeaderLeftClassName = 'flex items-center gap-1.5 text-sm font-medium text-text-secondary'

/// localStorage key holding a record of section id -> collapsed, mirroring LogPreview's VISIBLE_PARAM_COLUMNS_STORAGE_KEY pattern.
const COLLAPSED_SECTIONS_STORAGE_KEY = 'ottyl.collapsedSections'

function loadCollapsedSections(): Record<string, boolean> {
  try {
    const raw = localStorage.getItem(COLLAPSED_SECTIONS_STORAGE_KEY)
    if (!raw) return {}
    const parsed = JSON.parse(raw)
    return parsed && typeof parsed === 'object' ? parsed : {}
  } catch {
    return {}
  }
}

function saveCollapsedSections(sections: Record<string, boolean>) {
  try {
    localStorage.setItem(COLLAPSED_SECTIONS_STORAGE_KEY, JSON.stringify(sections))
  } catch {
    // best-effort — a private browsing mode or full storage just means the
    // collapsed state won't persist across reloads.
  }
}

/// Returns only the boolean + setter, not a conditional-render helper — callers keep rendering their subtree and hide it with CSS (`hidden`), so collapsing never unmounts in-progress form state.
export function useSectionCollapsed(sectionId: string): [boolean, (next: boolean) => void] {
  const [collapsed, setCollapsedState] = useState(() => loadCollapsedSections()[sectionId] ?? false)

  function setCollapsed(next: boolean) {
    setCollapsedState(next)
    const all = loadCollapsedSections()
    all[sectionId] = next
    saveCollapsedSections(all)
  }

  return [collapsed, setCollapsed]
}

/// Chevron indicator for a section's collapsed/expanded state. For the title-bar sections
/// (Alerts/Metrics/Params/Dashboards), the whole header row is the click target (see
/// `sectionHeaderInteractiveClassName`) and `onToggle` is omitted — this renders as a
/// non-interactive, decorative `span` rather than a nested `<button>`, with `aria-expanded`
/// living on the header row itself. `onToggle` stays available for the log viewer's toggle
/// (`App.tsx`), which sits in a filter toolbar rather than a plain title bar — there the
/// chevron itself remains a dedicated button.
export function CollapseToggle({ collapsed, onToggle }: { collapsed: boolean; onToggle?: () => void }) {
  if (!onToggle) {
    return (
      <span
        aria-hidden="true"
        className="flex h-5 w-5 shrink-0 items-center justify-center rounded-full border border-border-soft bg-surface-2 text-xs leading-none text-text-muted"
      >
        {collapsed ? '▸' : '▾'}
      </span>
    )
  }
  return (
    <button
      type="button"
      onClick={onToggle}
      title={collapsed ? 'Expand section' : 'Collapse section'}
      aria-label={collapsed ? 'Expand section' : 'Collapse section'}
      aria-expanded={!collapsed}
      className="flex h-5 w-5 shrink-0 items-center justify-center rounded-full border border-border-soft bg-surface-2 text-xs leading-none text-text-muted hover:border-border-strong hover:text-text-secondary"
    >
      {collapsed ? '▸' : '▾'}
    </button>
  )
}

/// Keyboard handler for a header row using `sectionHeaderInteractiveClassName`: Enter/Space
/// activate it like a button, matching the `role="button"` semantics on the row.
export function handleSectionHeaderKeyDown(onToggle: () => void) {
  return (e: React.KeyboardEvent) => {
    if (e.key === 'Enter' || e.key === ' ') {
      e.preventDefault()
      onToggle()
    }
  }
}

/// The four primary sections poppable into their own tab; matches the `?section=` query param a standalone page reads.
export type PopOutSectionId = 'log' | 'params' | 'metrics' | 'dashboards'

/// A rolling preset (anything but a manually dragged/fixed range) is carried over by id so the popped-out tab can resolve and keep re-resolving its own independent window of the same size, instead of freezing whatever absolute bounds happened to be active at click time. A fixed/dragged range has no such id, so it's carried over as absolute bounds, same as before.
function popOutUrl(section: PopOutSectionId, options?: { range?: TimeRange | null; presetId?: TimeRangePresetId | null }): string {
  const query = new URLSearchParams({ section })
  if (options?.presetId != null) {
    query.set('preset', options.presetId)
  } else if (options?.range) {
    query.set('startMs', String(options.range.startMs))
    query.set('endMs', String(options.range.endMs))
  }
  return `?${query.toString()}`
}

/// `range`/`activePreset` are only needed for sections without their own LogTimeline — the popped-out page can't pick a range itself until it mounts, so the current one is carried over via query params.
export function PopOutButton({
  section,
  range,
  activePreset,
}: {
  section: PopOutSectionId
  range?: TimeRange | null
  activePreset?: TimeRangePresetId | null
}) {
  return (
    <button
      type="button"
      onClick={(e) => {
        e.stopPropagation()
        window.open(popOutUrl(section, { range, presetId: activePreset }), '_blank')
      }}
      title="Open in new tab"
      aria-label="Open in new tab"
      className="flex h-5 w-5 shrink-0 items-center justify-center rounded-full border border-border-soft bg-surface-2 text-xs leading-none text-text-muted hover:border-border-strong hover:text-text-secondary"
    >
      ↗
    </button>
  )
}