import { useMemo, useState } from "react";
import { useQuery } from "@tanstack/react-query";
import { AlertCircle, CheckCircle2, ClipboardCheck, Download, FlaskConical, GitPullRequest, Plus, Trash2, Copy, Upload, X } from "lucide-react";
import {
  asWorkspaceApiError, exportWorkspace, getWorkspace, getWorkspaceRegistryStatus, importWorkspace,
  listWorkspaces, pullWorkspaceRegistry, testWorkspace, validateWorkspace, type CanonicalWorkspace,
  type PublishWorkspaceRequest, type WorkspaceRecord, type WorkspaceRevision,
} from "../api/workspaces";
import { workspaceDeletionDrafts, workspaceDrafts, type WorkspaceDeletionDraft, type WorkspaceDraft } from "../workspaces/drafts";
import { Button } from "../components/ui/button";
import { Dialog, DialogContent, DialogDescription, DialogHeader, DialogTitle } from "../components/ui/dialog";
import { WorkspaceEditor } from "./WorkspaceEditor";
import { WorkspacePublishDialog } from "./WorkspacePublishDialog";

const EMPTY_COMMIT = "0".repeat(40);

function newWorkspace(): CanonicalWorkspace {
  return {
    workspace: { schema_version: 2, id: "new-workspace", name: "New workspace", language: "en" },
    dwh: { engine: "postgres", database: "database", schema: "public", supported_transports: ["postgres_direct"] },
    semantic_index: {
      vector_store: { engine: "pgvector", database: "vectors", schema: "public", collection: "documents", dimensions: 768, distance: "cosine", supported_transports: ["pgvector_direct"] },
      embedding: { provider: "ollama_compatible", model: "nomic-embed-text", dimensions: 768 },
    },
    llm_policy: { allowed: ["zai/glm-5.2"] },
  };
}

function draftFromRecord(record: WorkspaceRecord): WorkspaceDraft {
  return {
    workspaceId: record.workspace.workspace.id,
    baseCommit: record.revision.commit,
    baseBlob: record.revision.blob,
    workspace: record.workspace,
    updatedAt: new Date().toISOString(),
  };
}

function proposedId(id: string): string {
  const copy = `${id.slice(0, 58)}-copy`;
  // A max-length source ending in "-copy" would otherwise reproduce itself.
  return copy === id ? `${id.slice(0, 61)}-2` : copy;
}

function QueryError({ name, message, retryLabel, onRetry }: {
  name: string;
  message: string;
  retryLabel: string;
  onRetry: () => void;
}) {
  return <div role="alert" aria-label={name} className="grid gap-2 rounded-md border border-destructive/30 bg-destructive/5 p-3 text-sm"><p>{message}</p><div><Button size="sm" variant="outline" onClick={onRetry}>{retryLabel}</Button></div></div>;
}

export function WorkspaceManager({ open, onClose }: { open: boolean; onClose: () => void }) {
  const [selectedId, setSelectedId] = useState<string>();
  const [localDraft, setLocalDraft] = useState<WorkspaceDraft>();
  const [notice, setNotice] = useState<string>();
  const [diagnostics, setDiagnostics] = useState<string[]>([]);
  const [deletionDraft, setDeletionDraft] = useState<WorkspaceDeletionDraft>();
  const [publishRequest, setPublishRequest] = useState<PublishWorkspaceRequest>();
  const [transferring, setTransferring] = useState(false);
  const statusQuery = useQuery({ queryKey: ["workspace-registry-status"], queryFn: getWorkspaceRegistryStatus, enabled: open });
  const workspacesQuery = useQuery({ queryKey: ["workspaces"], queryFn: listWorkspaces, enabled: open });
  const detailQuery = useQuery({
    queryKey: ["workspace", selectedId],
    queryFn: () => getWorkspace(selectedId!),
    enabled: Boolean(open && selectedId && !localDraft),
  });
  const status = statusQuery.data;
  const workspaces = workspacesQuery.data ?? [];
  const record = detailQuery.data;

  const savedDraft = selectedId && !localDraft ? workspaceDrafts.load(selectedId) : undefined;
  const savedDeletionDraft = selectedId && !deletionDraft ? workspaceDeletionDrafts.load(selectedId) : undefined;
  const currentDraft = localDraft ?? savedDraft ?? (record ? draftFromRecord(record) : undefined);
  const activeDeletionDraft = deletionDraft ?? savedDeletionDraft;
  const canTest = Boolean(record && currentDraft?.workspaceId === record.workspace.workspace.id);
  const selectedSummary = useMemo(() => workspaces.find((workspace) => workspace.id === selectedId), [selectedId, workspaces]);

  function selectWorkspace(id: string) {
    setSelectedId(id);
    setLocalDraft(undefined);
    setDeletionDraft(undefined);
    setNotice(undefined);
    setDiagnostics([]);
    setPublishRequest(undefined);
  }

  function createWorkspace() {
    const draft: WorkspaceDraft = { workspaceId: "new-workspace", baseCommit: EMPTY_COMMIT, workspace: newWorkspace(), updatedAt: new Date().toISOString() };
    setSelectedId(draft.workspaceId);
    setLocalDraft(draft);
    setDeletionDraft(undefined);
    setNotice("New draft. Choose its immutable workspace ID before saving.");
    setDiagnostics([]);
    setPublishRequest(undefined);
  }

  function duplicateWorkspace() {
    if (!currentDraft) return;
    const id = proposedId(currentDraft.workspace.workspace.id);
    const duplicate: WorkspaceDraft = {
      ...currentDraft,
      workspaceId: id,
      workspace: { ...currentDraft.workspace, workspace: { ...currentDraft.workspace.workspace, id, name: `${currentDraft.workspace.workspace.name} copy` } },
      updatedAt: new Date().toISOString(),
    };
    setSelectedId(id);
    setLocalDraft(duplicate);
    setDeletionDraft(undefined);
    setNotice("Duplicate draft. Give it a new immutable workspace ID before publishing.");
    setPublishRequest(undefined);
  }

  function saveDraft(draft: WorkspaceDraft) {
    workspaceDrafts.save(draft);
    setSelectedId(draft.workspaceId);
    setLocalDraft(draft);
    setNotice("Draft saved in this browser.");
  }

  function requestPublish(request: PublishWorkspaceRequest) {
    if (request.action !== "delete") {
      const nextDraft: WorkspaceDraft = {
        workspaceId: request.workspace.workspace.id,
        baseCommit: request.baseCommit,
        ...(request.action === "update" ? { baseBlob: request.baseBlob } : {}),
        workspace: request.workspace,
        updatedAt: new Date().toISOString(),
      };
      workspaceDrafts.save(nextDraft);
      setLocalDraft(nextDraft);
      setSelectedId(nextDraft.workspaceId);
    }
    setNotice(undefined);
    setDiagnostics([]);
    setPublishRequest(request);
  }

  function requestDeletionPublish() {
    if (!activeDeletionDraft) return;
    requestPublish({ action: "delete", id: activeDeletionDraft.id, baseCommit: activeDeletionDraft.baseCommit, baseBlob: activeDeletionDraft.baseBlob });
  }

  async function pullLatest() {
    setNotice(undefined);
    setDiagnostics([]);
    try {
      await pullWorkspaceRegistry();
      await Promise.all([statusQuery.refetch(), workspacesQuery.refetch()]);
      setNotice("Registry updated. Reload a workspace to review its latest revision.");
    } catch (error) {
      const safe = asWorkspaceApiError(error);
      setDiagnostics([safe ? `${safe.code}: ${safe.message}` : "git_unavailable: Registry pull could not be completed"]);
      throw error;
    }
  }

  function reloadWorkspace() {
    if (selectedId) {
      workspaceDrafts.discard(selectedId);
      workspaceDeletionDrafts.discard(selectedId);
    }
    setLocalDraft(undefined);
    setDeletionDraft(undefined);
    setPublishRequest(undefined);
    setNotice("Workspace reloaded from the registry. Your prior browser draft was discarded.");
    setDiagnostics([]);
    void detailQuery.refetch();
  }

  async function importBundle(file: File | undefined) {
    if (!file) return;
    setTransferring(true);
    setNotice(undefined);
    setDiagnostics([]);
    try {
      const result = await importWorkspace(file);
      const imported: WorkspaceDraft = {
        workspaceId: result.draft.workspace.workspace.id,
        baseCommit: EMPTY_COMMIT,
        workspace: result.draft.workspace,
        updatedAt: new Date().toISOString(),
      };
      workspaceDrafts.save(imported);
      setSelectedId(imported.workspaceId);
      setLocalDraft(imported);
      setDeletionDraft(undefined);
      setPublishRequest(undefined);
      setNotice("Imported draft saved in this browser. Validate it before publishing.");
    } catch (error) {
      const safe = asWorkspaceApiError(error);
      setDiagnostics([safe ? `${safe.code}: ${safe.message}` : "workspace_invalid: Workspace bundle could not be imported"]);
    } finally {
      setTransferring(false);
    }
  }

  async function downloadBundle() {
    if (!record) return;
    setTransferring(true);
    setNotice(undefined);
    setDiagnostics([]);
    try {
      const bundle = await exportWorkspace(record.workspace.workspace.id);
      const url = URL.createObjectURL(bundle);
      const link = document.createElement("a");
      link.href = url;
      link.download = `${record.workspace.workspace.id}.zip`;
      link.click();
      URL.revokeObjectURL(url);
      setNotice("Workspace bundle downloaded.");
    } catch (error) {
      const safe = asWorkspaceApiError(error);
      setDiagnostics([safe ? `${safe.code}: ${safe.message}` : "workspace_invalid: Workspace bundle could not be exported"]);
    } finally {
      setTransferring(false);
    }
  }

  function published(revision: WorkspaceRevision | undefined) {
    const publishedRequest = publishRequest;
    if (publishedRequest?.action === "delete") {
      workspaceDeletionDrafts.discard(publishedRequest.id);
      setSelectedId(undefined);
    } else if (publishedRequest) {
      workspaceDrafts.discard(publishedRequest.workspace.workspace.id);
      setSelectedId(publishedRequest.workspace.workspace.id);
    }
    setLocalDraft(undefined);
    setDeletionDraft(undefined);
    setPublishRequest(undefined);
    setNotice(revision ? `Published revision ${revision.commit.slice(0, 12)}.` : "Workspace published.");
    void Promise.all([statusQuery.refetch(), workspacesQuery.refetch(), detailQuery.refetch()]);
  }

  function saveResolvedDraft(draft: WorkspaceDraft) {
    workspaceDrafts.save(draft);
    setSelectedId(draft.workspaceId);
    setLocalDraft(draft);
    setDeletionDraft(undefined);
    setPublishRequest(undefined);
    setDiagnostics([]);
    setNotice(`Revised draft saved with registry revision ${draft.baseCommit.slice(0, 12)}. Validate it before publishing.`);
  }

  async function validateCurrent() {
    if (!currentDraft) return;
    setNotice(undefined);
    setDiagnostics([]);
    try {
      const result = await validateWorkspace(currentDraft.workspace);
      setLocalDraft({ ...currentDraft, workspace: result.workspace, updatedAt: new Date().toISOString() });
      setNotice("Workspace definition is valid.");
    } catch (error) {
      const safe = asWorkspaceApiError(error);
      setDiagnostics([safe ? `${safe.code}: ${safe.message}` : "workspace_invalid: Validation could not be completed"]);
    }
  }

  async function testCurrent() {
    if (!record) return;
    setNotice(undefined);
    setDiagnostics([]);
    try {
      const result = await testWorkspace(record.workspace.workspace.id);
      setDiagnostics(result.diagnostics.map((diagnostic) => `${diagnostic.code}: ${diagnostic.message}`));
      if (result.diagnostics.length === 0) setNotice(result.activatable ? "Installation test passed." : "Installation test completed.");
    } catch (error) {
      const safe = asWorkspaceApiError(error);
      setDiagnostics([safe ? `${safe.code}: ${safe.message}` : "connector_unavailable: Installation test could not be completed"]);
    }
  }

  function stageDeletion() {
    if (!currentDraft?.baseBlob || !record || currentDraft.workspaceId !== record.workspace.workspace.id) return;
    const draft = { id: currentDraft.workspaceId, baseCommit: currentDraft.baseCommit, baseBlob: currentDraft.baseBlob, updatedAt: new Date().toISOString() };
    workspaceDeletionDrafts.save(draft);
    setDeletionDraft(draft);
    setNotice("Deletion draft staged locally.");
    setDiagnostics([]);
  }

  return (
    <Dialog open={open} onOpenChange={(nextOpen) => { if (!nextOpen) onClose(); }}>
      <DialogContent showCloseButton={false} className="max-h-[min(90vh,54rem)] max-w-[min(94vw,74rem)] overflow-hidden p-0">
        <DialogHeader className="border-b border-border/70 px-5 pb-4 pt-5 pr-12">
          <DialogTitle>Workspace management</DialogTitle>
          <DialogDescription>Draft shared workspace definitions locally. Installation bindings and secrets stay outside this page.</DialogDescription>
        </DialogHeader>
        <button type="button" aria-label="Close workspace management" onClick={onClose} className="absolute right-3 top-3 grid size-7 place-items-center rounded-md text-muted-foreground hover:bg-muted hover:text-foreground"><X className="size-4" /></button>
        <div className="grid max-h-[calc(min(90vh,54rem)-6.75rem)] min-h-[32rem] grid-cols-[14rem_minmax(0,1fr)] overflow-hidden">
          <nav aria-label="Workspaces" className="flex min-h-0 flex-col border-r border-border/70 bg-muted/30 p-3">
            <Button size="sm" className="mb-3 w-full" onClick={createWorkspace}><Plus />New workspace</Button>
            <label className="mb-2 inline-flex h-7 cursor-pointer items-center justify-center gap-1 rounded-md border border-input px-3 text-[0.8rem] font-semibold text-foreground shadow-xs hover:bg-muted has-[:disabled]:cursor-not-allowed has-[:disabled]:opacity-50"><Upload className="size-3.5" />Import bundle<input aria-label="Import workspace bundle" type="file" accept="application/zip,.zip" className="sr-only" disabled={transferring} onChange={(event) => { const file = event.currentTarget.files?.[0]; event.currentTarget.value = ""; void importBundle(file); }} /></label>
            <Button size="sm" variant="outline" className="mb-3 w-full" disabled={transferring} onClick={() => { void pullLatest(); }}><GitPullRequest />Pull latest registry</Button>
            <div className="min-h-0 flex-1 overflow-y-auto">
              {workspacesQuery.isLoading ? <p className="p-2 text-xs text-muted-foreground">Loading workspaces…</p> : workspacesQuery.isError ? <QueryError name="Workspace list failed" message="Could not load workspaces." retryLabel="Retry workspace list" onRetry={() => { void workspacesQuery.refetch(); }} /> : workspaces.map((workspace) => (
                <button key={workspace.id} type="button" aria-label={workspace.displayName} aria-current={selectedId === workspace.id ? "page" : undefined} onClick={() => selectWorkspace(workspace.id)} className="mb-1 w-full rounded-md px-2.5 py-2 text-left text-sm hover:bg-muted aria-[current=page]:bg-primary/10 aria-[current=page]:font-semibold">
                  <span className="block truncate">{workspace.displayName}</span>
                  <span className="block truncate text-xs text-muted-foreground">{workspace.id}</span>
                </button>
              ))}
              {!workspacesQuery.isLoading && !workspacesQuery.isError && workspaces.length === 0 && <p className="p-2 text-xs text-muted-foreground">No published workspaces.</p>}
            </div>
            <div className="border-t border-border/70 pt-3 text-xs text-muted-foreground">
              <p className="font-semibold text-foreground">Git status</p>
              {statusQuery.isError ? <QueryError name="Workspace registry status failed" message="Could not load registry status." retryLabel="Retry registry status" onRetry={() => { void statusQuery.refetch(); }} /> : statusQuery.isLoading ? <p>Loading…</p> : status && <><p>{status.branch}</p>{status.head && <p className="font-mono">Commit {status.head.slice(0, 12)}</p>}<p>{status.degraded ? "Degraded" : "Current"} · ↑{status.ahead} ↓{status.behind}</p></>}
            </div>
          </nav>

          <div className="min-w-0 overflow-y-auto px-5 py-5">
            {detailQuery.isError && selectedId && !localDraft ? <QueryError name="Workspace details failed" message="Could not load workspace details." retryLabel="Retry workspace details" onRetry={() => { void detailQuery.refetch(); }} /> : !currentDraft && !detailQuery.isLoading && <div className="grid min-h-64 place-items-center text-center"><div><h3 className="font-heading font-semibold">Select a workspace</h3><p className="mt-1 text-sm text-muted-foreground">Review an existing definition or start a browser-only draft.</p></div></div>}
            {!detailQuery.isError && (currentDraft || detailQuery.isLoading) && (
              <>
                {detailQuery.isLoading && !currentDraft ? <p className="text-sm text-muted-foreground">Loading workspace definition…</p> : currentDraft && <>
                  <div className="mb-5 flex flex-wrap items-start justify-between gap-3 border-b border-border/70 pb-4">
                    <div>
                      <p className="thot-label">Workspace definition</p>
                      <h2 className="font-heading text-lg font-semibold">{currentDraft.workspace.workspace.name}</h2>
                      <p className="font-mono text-xs text-muted-foreground">{currentDraft.workspaceId}</p>
                    </div>
                    <div className="flex flex-wrap gap-2">
                      <Button size="sm" variant="outline" disabled={!record || transferring} onClick={() => { void downloadBundle(); }}><Download />Export workspace bundle</Button>
                      <Button size="sm" variant="outline" onClick={duplicateWorkspace}><Copy />Duplicate workspace</Button>
                      <Button size="sm" variant="outline" onClick={validateCurrent}><ClipboardCheck />Validate workspace</Button>
                      <Button size="sm" variant="outline" disabled={!canTest} onClick={testCurrent}><FlaskConical />Test on this installation</Button>
                      <Button size="sm" variant="destructive" disabled={!canTest || !currentDraft.baseBlob} onClick={stageDeletion}><Trash2 />Delete workspace</Button>
                    </div>
                  </div>
                  {notice && <p role="status" className="mb-4 flex items-center gap-2 rounded-md border border-border bg-muted/50 px-3 py-2 text-sm"><CheckCircle2 className="size-4 text-primary" />{notice}</p>}
                  {diagnostics.length > 0 && <div data-testid="workspace-diagnostics" aria-live="polite" className="mb-4 grid gap-1 rounded-md border border-amber-500/30 bg-amber-500/10 px-3 py-2 text-sm">{diagnostics.map((diagnostic) => <p key={diagnostic} className="flex items-start gap-2"><AlertCircle className="mt-0.5 size-4 shrink-0 text-amber-700" />{diagnostic}</p>)}</div>}
                  {activeDeletionDraft && <div className="mb-4 rounded-md border border-destructive/30 bg-destructive/5 px-3 py-2 text-sm"><p className="font-semibold">Deletion draft</p><p>The published workspace is unchanged. Validation and a separate confirmation are required before this deletion is published.</p><div className="mt-2 flex gap-2"><Button size="xs" variant="ghost" onClick={() => { workspaceDeletionDrafts.discard(activeDeletionDraft.id); setDeletionDraft(undefined); setNotice(undefined); }}>Discard deletion draft</Button><Button size="xs" variant="destructive" onClick={requestDeletionPublish}>Publish deletion</Button></div></div>}
                  <WorkspaceEditor draft={currentDraft} idLocked={Boolean(currentDraft.baseBlob && selectedSummary?.id === currentDraft.workspaceId)} onSaveDraft={saveDraft} onPublish={async (request) => { requestPublish(request); }} />
                  <section className="mt-6 border-t border-border/70 pt-5" aria-label="Git status and history">
                    <h3 className="font-heading text-sm font-semibold">Git status &amp; history</h3>
                    <p className="mt-2 text-sm text-muted-foreground">{status?.degraded ? "Using the last valid local snapshot." : "Registry checkout is current."}</p>
                    {record && <p className="mt-1 font-mono text-xs text-muted-foreground">Revision {record.revision.commit.slice(0, 12)} · {record.revision.state}</p>}
                  </section>
                </>}
              </>
            )}
          </div>
        </div>
      </DialogContent>
      {publishRequest && <WorkspacePublishDialog open={Boolean(publishRequest)} request={publishRequest} onOpenChange={(nextOpen) => { if (!nextOpen) setPublishRequest(undefined); }} onPublished={published} onResolved={saveResolvedDraft} onPull={pullLatest} onReload={reloadWorkspace} />}
    </Dialog>
  );
}