/**
 * Split-View Dual Chat Layout
 * Desktop-only (≥1024px) side-by-side chat sessions
 * Splits the CHAT AREA inside .app, not the whole layout
 */

/* ==========================================================================
   Split View Variables
   ========================================================================== */

:root {
  --split-ratio: 0.5; /* Default 50/50 split, updated by drag */
  --split-handle-width: 4px;
  --split-min-width: 320px;
  --split-transition: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* ==========================================================================
   Split Chat Container
   ========================================================================== */

/* Default: single column, primary takes all space */
.split-chat-container {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 0;
  overflow: hidden;
}

/* Desktop: when split-view is active, switch to row layout */
@media (min-width: 1024px) {
  body.split-view-active .split-chat-container {
    flex-direction: row;
  }
}

/* ==========================================================================
   Primary Chat Pane
   ========================================================================== */

.split-pane-primary {
  display: flex;
  flex-direction: column;
  flex: 1;
  min-height: 0;
  min-width: 0;
  overflow: hidden;
}

@media (min-width: 1024px) {
  body.split-view-active .split-pane-primary {
    flex: 0 0 calc(var(--split-ratio) * (100% - var(--split-handle-width) - 1px));
    min-width: var(--split-min-width);
  }

  /* Only animate on open/close, not during drag */
  body.split-view-active:not(.split-dragging) .split-pane-primary {
    transition: flex var(--split-transition);
  }
}

/* ==========================================================================
   Split View Button (Header)
   ========================================================================== */

#splitViewBtn {
  position: relative;
}

/* Glow effect when activated */
body.split-view-active #splitViewBtn {
  color: var(--accent);
  background: var(--accent-10);
}

body.split-view-active #splitViewBtn::after {
  content: '';
  position: absolute;
  inset: -2px;
  border: 2px solid var(--accent);
  border-radius: var(--radius-md);
  opacity: 0;
  animation: split-btn-glow 1s ease-out;
}

@keyframes split-btn-glow {
  0% {
    opacity: 1;
    transform: scale(1);
  }
  100% {
    opacity: 0;
    transform: scale(1.2);
  }
}

/* Mobile: split-view cannot activate */
@media (max-width: 1023px) {
  .split-pane-secondary,
  .split-drag-handle {
    display: none !important;
  }

  #splitViewBtn {
    display: none !important;
  }
}

/* ==========================================================================
   Secondary Chat Pane
   ========================================================================== */

.split-pane-secondary {
  display: none;
  flex-direction: column;
  background: transparent;
  overflow: hidden;
  min-width: 0;
  border-left: 1px solid var(--border);
}

@media (min-width: 1024px) {
  body.split-view-active .split-pane-secondary {
    display: flex;
    flex: 0 0 calc((1 - var(--split-ratio)) * (100% - var(--split-handle-width) - 1px));
    min-width: var(--split-min-width);
    animation: split-pane-slide-in var(--split-transition);
  }
}

@keyframes split-pane-slide-in {
  from {
    opacity: 0;
    transform: translateX(20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* ==========================================================================
   Primary Pane Header
   Hidden in single-pane mode; visible only when split-view is active.
   Layout: [Left: icon + session picker + model picker] [Right: tool + context]
   ========================================================================== */

/* Always visible — provides agent context in both single-pane and split-view */
.split-primary-header {
  display: flex;
  align-items: center;
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--border);
  background: var(--bg-header, var(--bg));
  flex-shrink: 0;
  min-height: 48px;
  gap: var(--space-2);
}

/* Left group: session picker + model selector */
.split-primary-left {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  flex: 1;
  overflow: hidden;
}

.split-primary-info {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  flex-shrink: 1;
  border-radius: var(--radius-md);
  padding: var(--space-1) var(--space-2);
  margin: calc(-1 * var(--space-1)) calc(-1 * var(--space-2));
  transition: background 0.15s ease;
  cursor: pointer;
}

.split-primary-info:hover {
  background: var(--accent-10);
}

.split-primary-info:active {
  background: var(--accent-20);
}

.split-primary-icon {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.split-primary-name {
  font-size: var(--text-base);
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 120px;
}

.split-primary-chevron {
  flex-shrink: 0;
  color: var(--text-muted);
  transition: transform 0.2s ease, color 0.15s ease;
}

.split-primary-info:hover .split-primary-chevron {
  color: var(--accent);
}

/* Model selector sits directly after session picker in the left group */
.model-selector {
  max-width: 180px;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  flex-shrink: 1;
}

@media (max-width: 768px) {
  .model-selector {
    max-width: 100px;
    font-size: 0.8rem;
  }
}

.split-primary-left .model-selector {
  flex-shrink: 1;
}

/* ==========================================================================
   Secondary Pane Header
   Layout: [Left: icon + session picker + model picker] [Right: tool + context + resync + close]
   ========================================================================== */

.split-secondary-header {
  display: flex;
  align-items: center;
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--border);
  background: var(--bg-header, var(--bg));
  flex-shrink: 0;
  min-height: 48px;
  gap: var(--space-2);
}

/* Left group: session picker + model selector */
.split-secondary-left {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  flex: 1;
  overflow: hidden;
}

.split-secondary-info {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 0;
  flex-shrink: 1;
  border-radius: var(--radius-md);
  padding: var(--space-1) var(--space-2);
  margin: calc(-1 * var(--space-1)) calc(-1 * var(--space-2));
  transition: background 0.15s ease;
  cursor: pointer;
}

.split-secondary-info:hover {
  background: var(--accent-10);
}

.split-secondary-info:active {
  background: var(--accent-20);
}

.split-secondary-icon {
  font-size: var(--text-xl);
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  object-fit: cover;
}

.split-secondary-name {
  font-size: var(--text-base);
  font-weight: 600;
  color: var(--text);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 120px;
}

.split-secondary-chevron {
  flex-shrink: 0;
  color: var(--text-muted);
  transition: transform 0.2s ease, color 0.15s ease;
}

.split-secondary-info:hover .split-secondary-chevron {
  color: var(--accent);
}

/* Model selector sits directly after session picker in the left group */
.split-secondary-left .model-selector {
  flex-shrink: 0;
}

/* Resync + Close live inside .chat-header-controls on the right */
.split-secondary-resync {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.split-secondary-resync:hover {
  background: var(--accent-10);
  color: var(--accent);
}

.split-secondary-resync:active {
  transform: scale(0.95);
}

.split-secondary-resync.spinning svg {
  animation: resync-spin 0.8s ease-in-out;
}

@keyframes resync-spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

.split-secondary-close {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: all 0.2s ease;
  flex-shrink: 0;
  font-size: var(--text-2xl);
  line-height: 1;
}

.split-secondary-close:hover {
  background: var(--accent-10);
  color: var(--accent);
}

.split-secondary-close:active {
  transform: scale(0.95);
}

/* ==========================================================================
   Secondary Pane Messages Area
   Match primary .messages styling from app.css
   ========================================================================== */

.split-secondary-messages {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--space-4);
  padding-bottom: 80px;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  scroll-behavior: smooth;
  -webkit-overflow-scrolling: touch;
  min-width: 0;
}

/* Push messages to bottom when few */
.split-secondary-messages .messages-spacer {
  flex: 1;
}

/* Scrollbar — match primary */
.split-secondary-messages::-webkit-scrollbar { width: 8px; }
.split-secondary-messages::-webkit-scrollbar-track { background: rgba(0, 0, 0, 0.1); }
.split-secondary-messages::-webkit-scrollbar-thumb {
  background: var(--accent-30);
  border-radius: 4px;
}
.split-secondary-messages::-webkit-scrollbar-thumb:hover {
  background: var(--accent-50);
}

/* Message bubbles — match primary .message exactly */
.split-secondary-messages .message {
  max-width: 85%;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-xl);   /* matches app.css — was --radius-lg */
  font-size: var(--text-base);
  line-height: 1.45;                 /* matches app.css — was 1.6 */
  color: var(--text);
  word-wrap: break-word;
  overflow-wrap: break-word;
  min-width: 0;
  animation: message-fade-in 0.3s ease-out;
}

/* Prevent code blocks from blowing out the split pane width */
.split-secondary-messages .message pre {
  overflow-x: auto;
  max-width: 100%;
}

.split-secondary-messages .message code {
  overflow-wrap: break-word;
  word-break: break-all;
}

.split-secondary-messages .message pre code {
  word-break: normal;
}

.split-secondary-messages .message.assistant {
  align-self: flex-start;
  background: var(--assistant-bubble);
  border: 1px solid var(--accent-10);
  border-bottom-left-radius: var(--radius-sm);
}

.split-secondary-messages .message.user {
  align-self: flex-end;
  background: linear-gradient(135deg, var(--user-bubble), var(--user-accent-hover));
  border: 1px solid var(--accent-30);
  border-bottom-right-radius: var(--radius-sm);
}

/* Empty state */
.split-secondary-messages:empty::after,
.split-secondary-messages:has(> .messages-spacer:only-child)::after {
  content: 'Select an agent to start a conversation';
  color: var(--text-muted);
  font-size: var(--text-base);
  text-align: center;
  align-self: center;
  pointer-events: none;
}

/* ==========================================================================
   Secondary Pane Input Area
   Match primary .input-area / .text-field / .send-btn from app.css
   ========================================================================== */

.split-secondary-input {
  padding: var(--space-3) var(--space-4);
  background: color-mix(in srgb, var(--bg) 70%, transparent);
  -webkit-backdrop-filter: blur(12px) saturate(1.2);
  backdrop-filter: blur(12px) saturate(1.2);
  border-top: 1px solid var(--border);
  flex-shrink: 0;
}

.split-input-row {
  display: flex;
  align-items: flex-end;
  gap: var(--space-2);
}

/* Match primary .text-field — pill shape with own bg/border */
.split-text-field {
  flex: 1;
  background: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: var(--radius-2xl);
  padding: var(--space-2) var(--space-4);
  color: var(--text);
  font-size: var(--text-base);
  font-family: var(--font-sans);
  outline: none;
  transition: border-color 0.15s;
  resize: none;
  min-height: var(--space-10);
  max-height: 150px;
  overflow-y: auto;
  line-height: 1.4;
}

.split-text-field:focus {
  border-color: var(--accent);
  box-shadow: 0 0 15px var(--accent-20);
}

.split-text-field:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.split-text-field::placeholder {
  color: var(--text-dim);
}

/* Match primary .send-btn — circle with glow */
.split-send-btn {
  width: 44px;
  height: 44px;
  min-width: 44px;
  min-height: 44px;
  border-radius: var(--radius-full);
  border: none;
  background: var(--accent);
  color: var(--text-inverse, #fff);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
  box-shadow: 0 0 20px var(--accent-30);
  flex-shrink: 0;
}

.split-send-btn:hover {
  background: var(--accent-hover);
  box-shadow: 0 0 30px var(--accent-40);
}

.split-send-btn:active {
  transform: scale(0.95);
}

.split-send-btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  transform: none;
}

.split-send-btn svg {
  width: 18px;
  height: 18px;
}

/* ==========================================================================
   Session Picker Overlay
   ========================================================================== */

.split-chat-picker {
  position: absolute;
  inset: 0;
  background: var(--bg);
  z-index: 10;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  max-height: 100%;
}

/* Ensure parent constrains the absolute picker */
.split-pane-primary,
.split-pane-secondary {
  position: relative;
}

.split-chat-picker-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-3) var(--space-4);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  min-height: 48px;
}

.split-chat-picker-title {
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--text);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.split-chat-picker-close {
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: var(--text-xl);
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: all 0.15s;
}

.split-chat-picker-close:hover {
  background: var(--accent-10);
  color: var(--accent);
}

.split-chat-picker-list {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  padding: var(--space-3);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.split-chat-picker-item {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  background: var(--bg-input, var(--bg-secondary));
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  color: var(--text);
  font-size: var(--text-base);
  cursor: pointer;
  transition: all 0.15s;
  text-align: left;
  width: 100%;
}

.split-chat-picker-item:hover {
  border-color: var(--accent);
  background: var(--accent-10);
}

.split-chat-picker-item.active {
  border-color: var(--accent);
  box-shadow: 0 0 15px var(--accent-20);
}

.split-chat-picker-item.primary {
  opacity: 0.5;
}

.split-chat-picker-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.split-chat-picker-avatar-fallback {
  width: 32px;
  height: 32px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  line-height: 1;
  border-radius: 50%;
  background: var(--accent-10);
  color: var(--text);
}

.split-chat-picker-emoji {
  font-size: var(--text-xl);
  flex-shrink: 0;
}

.split-chat-picker-info {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 1px;
  min-width: 0;
}

.split-chat-picker-name {
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.split-chat-picker-model {
  font-size: var(--text-xs);
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.split-chat-picker-badge {
  font-size: var(--text-xs);
  font-weight: 600;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  background: var(--border);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.split-chat-picker-badge.active {
  background: var(--accent-20);
  color: var(--accent);
}

.split-chat-picker-empty {
  text-align: center;
  color: var(--text-muted);
  padding: var(--space-6);
  font-size: var(--text-base);
}

/* ==========================================================================
   Drag Handle
   ========================================================================== */

.split-drag-handle {
  display: none;
  position: relative;
  width: var(--split-handle-width);
  background: var(--border);
  cursor: col-resize;
  flex-shrink: 0;
  transition: background 0.2s ease;
  user-select: none;
}

@media (min-width: 1024px) {
  body.split-view-active .split-drag-handle {
    display: block;
  }

  .split-drag-handle:hover {
    background: var(--accent-30);
  }

  .split-drag-handle:active,
  .split-drag-handle.dragging {
    background: var(--accent);
  }

  /* Visual indicator on hover */
  .split-drag-handle::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 20px;
    height: 40px;
    background: var(--accent-20);
    border-radius: var(--radius-full);
    opacity: 0;
    transition: opacity 0.2s ease;
    pointer-events: none;
  }

  .split-drag-handle:hover::before {
    opacity: 1;
  }
}

/* ==========================================================================
   Accessibility
   ========================================================================== */

.split-drag-handle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Reduce motion */
@media (prefers-reduced-motion: reduce) {
  .split-pane-secondary,
  .split-drag-handle,
  #splitViewBtn::after,
  .split-input-row {
    animation: none !important;
    transition: none !important;
  }
}

/* ==========================================================================
   Loading State
   ========================================================================== */

.split-secondary-messages.loading::after {
  content: '';
  display: block;
  width: 40px;
  height: 40px;
  margin: var(--space-4) auto;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ==========================================================================
   Override: Primary chat max-width in split mode
   When split is active, primary should use all its allocated space
   ========================================================================== */

@media (min-width: 1024px) {
  body.split-view-active .app {
    max-width: none;
    min-width: 0;
  }

  body.split-view-active .split-chat-container {
    min-width: 0;
  }

  body.split-view-active .split-pane-primary .messages {
    max-width: none;
  }
}

/* ==========================================================================
   Side Panel Integration in Split-View Mode
   When split-view AND a panel are both open, the side panel should
   flow alongside the chat container instead of overlaying.
   ========================================================================== */

@media (min-width: 1024px) {
  /* Override: make side panel flow in layout-wrapper instead of fixed overlay */
  body.split-view-active.panel-open .side-panel {
    position: relative;
    top: auto;
    right: auto;
    width: 25%;
    min-width: 280px;
    max-width: 400px;
    height: 100%;
    z-index: auto;
    flex-shrink: 0;
  }

  /* App shrinks to make room for the panel in the flow */
  body.split-view-active.panel-open .app {
    max-width: none;
    margin-right: 0;
    flex: 1;
    min-width: 0;
  }
}

/* ==========================================================================
   Artifacts Split Pane
   When artifacts opens as a split pane, it replaces the secondary chat
   and uses the same flex/drag mechanics.
   ========================================================================== */

/* Artifacts as a split pane — mirrors .split-pane-secondary layout */
.split-artifacts-pane {
  display: none;
  flex-direction: column;
  background: var(--bg);
  overflow: hidden;
  min-width: 0;
  border-left: 1px solid var(--border);
}

@media (min-width: 1024px) {
  body.split-artifacts-active .split-artifacts-pane {
    display: flex;
    flex: 0 0 calc((1 - var(--split-ratio)) * (100% - var(--split-handle-width) - 1px));
    min-width: var(--split-min-width);
    animation: split-pane-slide-in var(--split-transition);
  }

  /* Show drag handle when artifacts split is active */
  body.split-artifacts-active .split-drag-handle {
    display: block;
  }

  /* Primary pane sizing when artifacts split is active */
  body.split-artifacts-active .split-pane-primary {
    flex: 0 0 calc(var(--split-ratio) * (100% - var(--split-handle-width) - 1px));
    min-width: var(--split-min-width);
  }

  body.split-artifacts-active:not(.split-dragging) .split-pane-primary {
    transition: flex var(--split-transition);
  }

  /* App max-width override */
  body.split-artifacts-active .app {
    max-width: none;
  }

  /* Artifacts panel header shows its own close button in split mode */
  body.split-artifacts-active .split-artifacts-pane .artifacts-panel-header {
    display: flex;
    padding: var(--space-3) var(--space-4);
    padding-top: var(--space-3);
    min-height: 48px;
    background: var(--bg);
  }

  /* Shrink panel buttons in split mode to match chat header buttons */
  body.split-artifacts-active .split-artifacts-pane .panel-close,
  body.split-artifacts-active .split-artifacts-pane .artifacts-panel-refresh {
    min-width: 28px;
    min-height: 28px;
    width: 28px;
    height: 28px;
    font-size: var(--text-lg);
  }

  body.split-artifacts-active .split-artifacts-pane .artifacts-tab {
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
      min-height: unset;
  }

  /* Override the panel-content to fill the pane */
  body.split-artifacts-active .split-artifacts-pane .panel-content {
    flex: 1;
    overflow-y: auto;
  }
}

/* Artifacts button glow when active (matches split-view button) */
body.split-artifacts-active #artifactsBtn {
  color: var(--accent);
  background: var(--accent-10);
}

/* Streaming animation for split view messages
   Uses @keyframes streamingRainbow defined in app.css.
   Add border so border-color animation is visible. */
.split-secondary-messages .message.streaming {
  position: relative;
  border: 1px solid transparent;
  animation: streamingRainbow 4s linear infinite;
}

/* Mobile: primary header always shows, add border-top so it reads as a section */
@media (max-width: 1023px) {
  .split-primary-header {
    border-top: 1px solid var(--border);
  }
}

/* ==========================================================================
   Split Chat File Upload
   ========================================================================== */

.split-image-preview {
  display: none;
  position: relative;
  padding: var(--space-2) var(--space-4);
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

.split-image-preview.visible {
  display: flex;
  align-items: center;
  gap: var(--space-3);
}

.split-image-preview img {
  max-height: 120px;
  max-width: 200px;
  border-radius: var(--radius-md);
  object-fit: contain;
}

.split-file-label {
  font-size: var(--text-sm);
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.split-file-label .file-size {
  color: var(--text-dim);
  font-size: var(--text-xs);
}

.split-preview-remove {
  position: absolute;
  top: var(--space-2);
  right: var(--space-4);
}

.split-attach-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  border-radius: var(--radius-md);
  transition: all 0.15s ease;
  flex-shrink: 0;
}

.split-attach-btn:hover {
  background: var(--accent-10);
  color: var(--accent);
}

.split-attach-btn:active {
  transform: scale(0.95);
}