/**
 * The 6 built-in tab descriptors: the plugin registers its own pages
 * (explorer / git / terminal / subagent / editor / diff) through the same
 * {@link BetterSidebarService} external plugins use — eating its own
 * dogfood. The terminal descriptor owns its quota (`TERMINAL_LIMIT`) and
 * mints `terminal:<n>` ids through `createTab`.
 */
import { IconBranchOutline16, IconCodeOutline16, IconFolderOpen16, IconThinkOutline16 } from '@deepseek-ai/dsh-client-ui-primitives'
import type { Context } from '../../context-types.ts'
import { allLeaves, isAgentTabId, type SidebarState } from '../state.ts'
import { t } from '../locales.ts'
import { openSidebarFile } from '../intercept.tsx'
import { ExplorerView } from '../ExplorerView.tsx'
import { EditorHost } from '../EditorHost.tsx'
import { TerminalView } from '../TerminalView.tsx'
import { GitView } from '../GitView.tsx'
import { DiffTab } from '../DiffTab.tsx'
import { SubagentView } from '../SubagentView.tsx'
import { IconTerminalOutline16, IconDiffOutline16 } from '../icons.tsx'
import type { TabDescriptor } from '../service.ts'

/** How many UI-owned terminals may be open at once (agent-owned ones are uncapped). */
export const TERMINAL_LIMIT = 3

/** Count UI-owned terminals (agent:` tabs excluded — they are the model's). */
function uiTerminalCount(state: SidebarState): number {
  return allLeaves(state.splits)
    .flatMap(leaf => leaf.tabs)
    .filter(tab => tab.type === 'terminal' && !isAgentTabId(tab.id)).length
}

/** The 6 built-in tab descriptors. */
export function builtinTabs(ctx: Context): readonly TabDescriptor[] {
  return [
    {
      id: 'editor',
      title: () => t('editor'),
      icon: (size: number) => <IconCodeOutline16 size={size} />,
      order: -1,
      hidden: true,
      dedupeKey: (tab) => tab.path,
      component: ({ ctx, store, scope, tab }) => (
        <EditorHost ctx={ctx} store={store} scope={scope} path={tab.path ?? ''} title={tab.title} />
      ),
    },
    {
      id: 'explorer',
      title: () => t('explorer'),
      icon: (size: number) => <IconFolderOpen16 size={size} />,
      order: 10,
      single: true,
      component: ({ ctx, store, scope, expanded, onToggleDir, onReferenceFile }) => (
        <ExplorerView
          sessionId={scope.sessionId}
          cwd={scope.cwd}
          expanded={expanded ?? []}
          onToggle={onToggleDir ?? (() => { /* no-op */ })}
          onOpenFile={(path) => { openSidebarFile(ctx, store, scope.sessionId, path) }}
          onReferenceFile={onReferenceFile ?? (() => { /* no-op */ })}
        />
      ),
    },
    {
      id: 'git',
      title: () => t('git'),
      icon: (size: number) => <IconBranchOutline16 size={size} />,
      order: 20,
      single: true,
      component: ({ ctx, store, scope, onOpenDiff }) => (
        <GitView
          scope={scope}
          onOpenFile={(path) => { openSidebarFile(ctx, store, scope.sessionId, path) }}
          onOpenDiff={onOpenDiff ?? (() => { /* no-op */ })}
        />
      ),
    },
    {
      id: 'subagent',
      title: () => t('subagent'),
      icon: (size: number) => <IconThinkOutline16 size={size} />,
      order: 30,
      single: true,
      // Declarative settings: the auto-open switch renders under this row in
      // the Side card settings page (the Subagent page's own related setting).
      settings: {
        toggles: [{
          key: 'autoOpenSubagent',
          title: () => t('settingsSubagentTitle'),
          desc: () => t('settingsSubagentDesc'),
        }],
      },
      component: ({ ctx, scope, visible, onSubagentJump }) => (
        <SubagentView
          sessionId={scope.sessionId}
          ctx={ctx}
          active={visible}
          onOpenChild={(address) => { onSubagentJump?.(address.childSessionId) }}
        />
      ),
    },
    {
      id: 'terminal',
      title: () => t('terminal'),
      icon: (size: number) => <IconTerminalOutline16 size={size} />,
      order: 40,
      available: (_ctx, _scope, state) => uiTerminalCount(state) < TERMINAL_LIMIT,
      // Declarative settings: the model-facing terminal tools switch renders
      // under this row in the Side card settings page (the Terminal page's
      // own related setting; the host gates the toolset on it independently).
      settings: {
        toggles: [{
          key: 'agentTerminalTools',
          title: () => t('settingsToolsTitle'),
          desc: () => t('settingsToolsDesc'),
        }],
      },
      createTab: (state) => {
        const count = uiTerminalCount(state)
        if (count >= TERMINAL_LIMIT) return null
        return {
          tab: {
            id: `terminal:${state.nextTerminal}`,
            type: 'terminal',
            title: `${t('terminal')} ${state.nextTerminal}`,
          },
          patch: { nextTerminal: state.nextTerminal + 1 },
        }
      },
      component: ({ scope, tab, store }) => (
        <TerminalView scope={scope} tabId={tab.id} store={store} />
      ),
    },
    {
      id: 'diff',
      title: () => t('git'),
      icon: (size: number) => <IconDiffOutline16 size={size} />,
      order: -1,
      hidden: true,
      dedupeKey: (tab) => tab.id,
      component: ({ scope, tab }) => (
        tab.diff === undefined ? null
          : <DiffTab sessionId={scope.sessionId} cwd={scope.cwd} diff={tab.diff} />
      ),
    },
  ]
}