@use '../styles/variables' as tokens;

// ============================================================================
// Accordion variables following three-level cascade strategy
// ============================================================================
$accordion-border-color: var(--vi-accordion-border-color, tokens.$outline);
$accordion-border-radius: var(--vi-accordion-border-radius, tokens.$border-radius-md);
$accordion-gap: var(--vi-accordion-gap, 0px);
$accordion-animation-duration: var(--vi-accordion-animation-duration, 200ms);

$accordion-item-header-padding: var(--vi-accordion-item-header-padding, #{tokens.$spacing-sm} #{tokens.$spacing-md});
$accordion-item-body-padding: var(--vi-accordion-item-body-padding, 0 #{tokens.$spacing-md} #{tokens.$spacing-md});
$accordion-item-header-bg: var(--vi-accordion-item-header-bg, transparent);
$accordion-item-header-bg-hover: var(--vi-accordion-item-header-bg-hover, tokens.$layer-hover-01);
$accordion-item-header-bg-open: var(--vi-accordion-item-header-bg-open, transparent);
$accordion-item-label-color: var(--vi-accordion-item-label-color, tokens.$text-primary);
$accordion-item-label-font-weight: var(--vi-accordion-item-label-font-weight, tokens.$font-weight-medium);
$accordion-item-chevron-color: var(--vi-accordion-item-chevron-color, tokens.$text-disabled);

.accordion {
  display: flex;
  flex-direction: column;
  gap: $accordion-gap;
  width: 100%;
}

.accordion-item {
  display: flex;
  flex-direction: column;
  width: 100%;
  box-sizing: border-box;

  &:not(:last-child) {
    border-bottom: 1px solid $accordion-border-color;
  }
}

.accordion-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: $accordion-item-header-padding;
  background-color: $accordion-item-header-bg;
  color: $accordion-item-label-color;
  font-family: var(--vi-accordion-font-family, #{tokens.$font-family-base});
  font-size: var(--vi-accordion-item-header-font-size, #{tokens.$font-size-base});
  font-weight: $accordion-item-label-font-weight;
  text-align: left;
  border: none;
  outline: none;
  cursor: pointer;
  box-sizing: border-box;
  transition: background-color $accordion-animation-duration ease,
              color $accordion-animation-duration ease;
  user-select: none;

  &:hover:not(:disabled) {
    background-color: $accordion-item-header-bg-hover;
  }

  &:disabled {
    cursor: not-allowed;
    opacity: 0.5;
  }

  // Standard focus ring system
  &:focus-visible {
    outline: 2px solid tokens.$focus;
    outline-offset: -2px;
  }
}

.accordion-header-content {
  display: flex;
  align-items: center;
  gap: tokens.$spacing-xs;
  flex: 1;
}

.accordion-label {
  flex: 1;
}

.accordion-chevron {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: $accordion-item-chevron-color;
  transition: transform $accordion-animation-duration ease;
  margin-inline-start: tokens.$spacing-xs;

  svg {
    width: #{tokens.$spacing-md};
    height: #{tokens.$spacing-md};
    fill: none;
    stroke: currentColor;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
  }
}

.accordion-panel {
  display: block;
  overflow: hidden;
  max-height: 0;
  opacity: 0;
  transition: max-height $accordion-animation-duration ease-out,
              opacity $accordion-animation-duration ease-out;
}

.accordion-panel-inner {
  padding: $accordion-item-body-padding;
  font-family: var(--vi-accordion-font-family, #{tokens.$font-family-base});
  font-size: #{tokens.$font-size-sm};
  color: #{tokens.$text-secondary};
  box-sizing: border-box;
}

// ============================================================================
// Variants
// ============================================================================

// Bordered variant: full border wrapper around each item
.accordion--bordered {
  border: 1px solid $accordion-border-color;
  border-radius: $accordion-border-radius;
  overflow: hidden;

  .accordion-item:last-child {
    border-bottom: none;
  }
}

// Flush variant: no outer border, full-width edge-to-edge
.accordion--flush,
.accordion-item--flush {
  border: none;
  border-radius: 0;

  .accordion-item {
    border-inline: none;
  }
  border-inline: none;
}

// Card variant: each item is a card with shadow and gap
.accordion--card {
  --vi-accordion-gap: 8px;
}

.accordion-item--card {
  border: 1px solid $accordion-border-color;
  border-radius: $accordion-border-radius;
  background-color: var(--vi-card-bg, tokens.$layer-01);
  box-shadow: var(--vi-shadow-sm, tokens.$shadow-sm);
  overflow: hidden;

  &:not(:last-child) {
    border-bottom: 1px solid $accordion-border-color;
  }
}

// ============================================================================
// Size overrides
// ============================================================================

.accordion--sm,
.accordion-item--sm {
  --vi-accordion-item-header-padding: #{tokens.$spacing-xs} #{tokens.$spacing-sm};
  --vi-accordion-item-body-padding: 0 #{tokens.$spacing-sm} #{tokens.$spacing-sm};
  --vi-accordion-item-header-font-size: #{tokens.$font-size-sm};
}

.accordion--md,
.accordion-item--md {
  --vi-accordion-item-header-padding: 14px 16px;
  --vi-accordion-item-body-padding: 0 16px 16px;
  --vi-accordion-item-header-font-size: #{tokens.$font-size-base};
}

.accordion--lg,
.accordion-item--lg {
  --vi-accordion-item-header-padding: #{tokens.$spacing-lg} #{tokens.$spacing-xl};
  --vi-accordion-item-body-padding: 0 #{tokens.$spacing-xl} #{tokens.$spacing-xl};
  --vi-accordion-item-header-font-size: #{tokens.$font-size-lg};
}

// ============================================================================
// Open & Motion states
// ============================================================================

.accordion-item--open {
  .accordion-header {
    background-color: $accordion-item-header-bg-open;
  }

  .accordion-chevron {
    transform: rotate(90deg);
  }

  .accordion-panel {
    max-height: var(--vi-accordion-panel-height, none);
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  .accordion-panel,
  .accordion-chevron,
  .accordion-header {
    transition: none !important;
  }
}