import { StateHydrator } from '@/components/state-hydrator';
import { readLayoutDefaults } from '@/lib/layout/read-layout-defaults';
import {
  fetchWorkflowSnapshot,
  fetchTaskSession,
  fetchTask,
  fetchUserSettings,
  listAgents,
  listAvailableAgents,
  listWorkflows,
  listRepositories,
  listTaskSessionMessages,
  listTaskSessions,
  listWorkspaces,
} from '@/lib/api';
import { toAgentProfileOption } from '@/lib/state/slices/settings/types';
import { listSessionTurns } from '@/lib/api/domains/session-api';
import { fetchTerminals } from '@/lib/api/domains/user-shell-api';
import type { ListMessagesResponse, Task } from '@/lib/types/http';
import type { Terminal } from '@/hooks/domains/session/use-terminals';
import { snapshotToState, taskToState } from '@/lib/ssr/mapper';
import { TaskPageContent } from '@/components/task/task-page-content';

export default async function SessionPage({
  params,
}: {
  params: Promise<{ sessionId: string }>;
}) {
  let initialState: ReturnType<typeof taskToState> | null = null;
  let task: Task | null = null;
  let sessionId: string | null = null;
  let initialTerminals: Terminal[] = [];
  const defaultLayouts = await readLayoutDefaults();

  try {
    const { sessionId: paramSessionId } = await params;
    sessionId = paramSessionId;

    const sessionResponse = await fetchTaskSession(sessionId, { cache: 'no-store' });
    const session = sessionResponse.session;
    if (!session?.task_id) {
      throw new Error('No task_id found for session');
    }

    task = await fetchTask(session.task_id, { cache: 'no-store' });
    const [snapshot, agents, repositoriesResponse, allSessionsResponse, availableAgentsResponse, workspacesResponse, workflowsResponse, turnsResponse, userSettingsResponse, terminalsResponse] = await Promise.all([
      fetchWorkflowSnapshot(task.workflow_id, { cache: 'no-store' }),
      listAgents({ cache: 'no-store' }),
      listRepositories(task.workspace_id, { includeScripts: true }, { cache: 'no-store' }),
      listTaskSessions(session.task_id, { cache: 'no-store' }),
      listAvailableAgents({ cache: 'no-store' }).catch(() => ({ agents: [] })),
      listWorkspaces({ cache: 'no-store' }).catch(() => ({ workspaces: [] })),
      listWorkflows(task.workspace_id, { cache: 'no-store' }).catch(() => ({ workflows: [] })),
      listSessionTurns(sessionId, { cache: 'no-store' }).catch(() => ({ turns: [], total: 0 })),
      fetchUserSettings({ cache: 'no-store' }).catch(() => null),
      fetchTerminals(sessionId).catch(() => []),
    ]);
    const repositories = repositoriesResponse.repositories ?? [];
    const allSessions = allSessionsResponse.sessions ?? [session];
    const availableAgents = availableAgentsResponse.agents ?? [];
    const workspaces = workspacesResponse.workspaces ?? [];
    const workflows = workflowsResponse.workflows ?? [];
    const turns = turnsResponse.turns ?? [];
    const userSettings = userSettingsResponse?.settings;

    // Transform terminals to frontend format
    initialTerminals = terminalsResponse.map((t) => ({
      id: t.terminal_id,
      type: t.initial_command ? 'script' as const : 'shell' as const,
      label: t.label,
      closable: t.closable,
    }));

    // Get repository scripts from the repository (already fetched with includeScripts)
    const repositoryId = task.repositories?.[0]?.repository_id;
    const repository = repositories.find(r => r.id === repositoryId);
    const scripts = repository?.scripts ?? [];

    let messagesResponse: ListMessagesResponse | null = null;
    try {
      // Load most recent messages in descending order, then reverse to show oldest-to-newest
      messagesResponse = await listTaskSessionMessages(
        sessionId,
        { limit: 50, sort: 'desc' },
        { cache: 'no-store' }
      );
    } catch (error) {
      console.warn(
        'Could not load session messages for SSR:',
        error instanceof Error ? error.message : String(error)
      );
    }

    const messages = messagesResponse?.messages ? [...messagesResponse.messages].reverse() : [];
    const taskState = taskToState(task, sessionId, {
      items: messages,
      hasMore: messagesResponse?.has_more ?? false,
      // oldestCursor should be the first (oldest) message ID for lazy loading older messages
      oldestCursor: messages[0]?.id ?? null,
    });

    initialState = {
      ...snapshotToState(snapshot),
      ...taskState,
      workspaces: {
        items: workspaces.map((workspace) => ({
          id: workspace.id,
          name: workspace.name,
          description: workspace.description ?? null,
          owner_id: workspace.owner_id,
          default_executor_id: workspace.default_executor_id ?? null,
          default_environment_id: workspace.default_environment_id ?? null,
          default_agent_profile_id: workspace.default_agent_profile_id ?? null,
          created_at: workspace.created_at,
          updated_at: workspace.updated_at,
        })),
        activeId: task.workspace_id,
      },
      workflows: {
        items: workflows.map((workflow) => ({
          id: workflow.id,
          workspaceId: workflow.workspace_id,
          name: workflow.name,
        })),
        activeId: task.workflow_id,
      },
      repositories: {
        itemsByWorkspaceId: {
          [task.workspace_id]: repositories,
        },
        loadingByWorkspaceId: {
          [task.workspace_id]: false,
        },
        loadedByWorkspaceId: {
          [task.workspace_id]: true,
        },
      },
      repositoryScripts: repositoryId ? {
        itemsByRepositoryId: {
          [repositoryId]: scripts,
        },
        loadingByRepositoryId: {
          [repositoryId]: false,
        },
        loadedByRepositoryId: {
          [repositoryId]: true,
        },
      } : {
        itemsByRepositoryId: {},
        loadingByRepositoryId: {},
        loadedByRepositoryId: {},
      },
      agentProfiles: {
        items: agents.agents.flatMap((agent) =>
          agent.profiles.map((profile) => toAgentProfileOption(agent, profile))
        ),
        version: 0,
      },
      taskSessions: {
        items: Object.fromEntries(allSessions.map((s) => [s.id, s])),
      },
      taskSessionsByTask: {
        itemsByTaskId: {
          [task.id]: allSessions,
        },
        loadingByTaskId: {
          [task.id]: false,
        },
        loadedByTaskId: {
          [task.id]: true,
        },
      },
      turns: {
        bySession: {
          [sessionId]: turns,
        },
        activeBySession: {
          // Find the most recent (last) incomplete turn
          [sessionId]: turns.filter((t) => !t.completed_at).pop()?.id ?? null,
        },
      },
      worktrees: {
        items: Object.fromEntries(
          allSessions
            .filter((s) => s.worktree_id)
            .map((s) => [
              s.worktree_id,
              {
                id: s.worktree_id!,
                sessionId: s.id,
                repositoryId: s.repository_id ?? undefined,
                path: s.worktree_path ?? undefined,
                branch: s.worktree_branch ?? undefined,
              },
            ])
        ),
      },
      sessionWorktreesBySessionId: {
        itemsBySessionId: Object.fromEntries(
          allSessions
            .filter((s) => s.worktree_id)
            .map((s) => [s.id, [s.worktree_id!]])
        ),
      },
      settingsAgents: {
        items: agents.agents,
      },
      settingsData: {
        agentsLoaded: true,
        executorsLoaded: false,
        environmentsLoaded: false,
      },
      availableAgents: {
        items: availableAgents,
        loaded: true,
        loading: false,
      },
      userSettings: {
        workspaceId: userSettings?.workspace_id || null,
        workflowId: userSettings?.workflow_filter_id || null,
        kanbanViewMode: userSettings?.kanban_view_mode || null,
        repositoryIds: Array.from(new Set(userSettings?.repository_ids ?? [])).sort(),
        preferredShell: userSettings?.preferred_shell || null,
        shellOptions: userSettingsResponse?.shell_options ?? [],
        defaultEditorId: userSettings?.default_editor_id || null,
        enablePreviewOnClick: userSettings?.enable_preview_on_click ?? false,
        chatSubmitKey: userSettings?.chat_submit_key ?? 'cmd_enter',
        reviewAutoMarkOnScroll: userSettings?.review_auto_mark_on_scroll ?? true,
        lspAutoStartLanguages: userSettings?.lsp_auto_start_languages ?? [],
        lspAutoInstallLanguages: userSettings?.lsp_auto_install_languages ?? [],
        lspServerConfigs: userSettings?.lsp_server_configs ?? {},
        loaded: Boolean(userSettings),
      },
    };
  } catch (error) {
    console.warn(
      'Could not SSR session (client will load via WebSocket):',
      error instanceof Error ? error.message : String(error)
    );
    initialState = null;
    task = null;
    sessionId = null;
  }

  return (
    <>
      {initialState ? <StateHydrator initialState={initialState} sessionId={sessionId ?? undefined} /> : null}
      <TaskPageContent
        task={task}
        sessionId={sessionId}
        initialRepositories={initialState?.repositories?.itemsByWorkspaceId?.[task?.workspace_id ?? ''] ?? []}
        initialScripts={initialState?.repositoryScripts?.itemsByRepositoryId?.[task?.repositories?.[0]?.repository_id ?? ''] ?? []}
        initialTerminals={initialTerminals}
        defaultLayouts={defaultLayouts}
      />
    </>
  );
}