import { useEffect, useState } from "react";
import { Link, useNavigate, useParams } from "react-router-dom";
import { LuArrowLeft, LuCopy, LuPause, LuPlay, LuSave } from "react-icons/lu";
import { errorMessage } from "../api/client.js";
import {
  useCreateWorkflow,
  useSaveWorkflow,
  useSetWorkflowEnabled,
  useWorkflow,
  useWorkflowRevision,
} from "../api/hooks.js";
import { DuplicateWorkflowDialog } from "../components/DuplicateWorkflowDialog.jsx";
import { NewWorkflowPresetDialog, shouldSkipNewWorkflowPreset } from "../components/NewWorkflowPresetDialog.jsx";
import { WorkflowFileIcon } from "../components/WorkflowFileIcon.jsx";
import { WorkflowVisualEditor } from "../components/workflow/WorkflowVisualEditor.jsx";
import { WorkflowHistoryPanel } from "../components/workflow/WorkflowHistoryPanel.jsx";
import {
  SaveWorkflowWarningsDialog,
  isSaveWarningsError,
  saveErrorMessage,
  saveWarningsFromError,
} from "../components/workflow/SaveWorkflowWarningsDialog.jsx";
import { ConfirmDialog } from "../components/ConfirmDialog.jsx";
import { WorkflowRevisionBanner } from "../components/workflow/WorkflowRevisionBanner.jsx";
import { NEW_WORKFLOW_YAML, parseWorkflowYaml } from "../lib/workflow-doc.js";
import { DEFAULT_OWNER } from "../lib/tenant.js";
import { useNotifications } from "../notifications.jsx";

function WorkflowEditorLayout({
  title,
  backTo = "/workflows",
  savePending,
  saveDisabled,
  saveError,
  onSave,
  onTest,
  onDuplicate,
  onToggleEnabled,
  enabled,
  enablePending,
  enableDisabled,
  enableError,
  children,
}) {
  return (
    <div className="flex h-[calc(100vh-5rem)] min-h-[32rem] flex-col gap-3">
      <div className="flex shrink-0 flex-wrap items-center gap-2">
        <Link to={backTo} className="btn btn-ghost btn-sm btn-square" aria-label="Back">
          <LuArrowLeft className="size-4" />
        </Link>
        <WorkflowFileIcon className="size-8 shrink-0" />
        <h1 className="truncate text-xl font-semibold">{title}</h1>
        <div className="flex-1" />
        {onToggleEnabled ? (
          <button
            type="button"
            className="btn btn-sm"
            disabled={enablePending || enableDisabled}
            onClick={onToggleEnabled}
          >
            {enablePending ? (
              <span className="loading loading-spinner loading-xs" />
            ) : enabled ? (
              <LuPause className="size-4" />
            ) : (
              <LuPlay className="size-4" />
            )}
            {enabled ? "Disable" : "Enable"}
          </button>
        ) : null}
        {onTest ? (
          <button type="button" className="btn btn-sm" onClick={onTest}>
            <LuPlay className="size-4" />
            Test
          </button>
        ) : null}
        {onDuplicate ? (
          <button type="button" className="btn btn-sm" onClick={onDuplicate}>
            <LuCopy className="size-4" />
            Duplicate
          </button>
        ) : null}
        <button
          type="button"
          className="btn btn-primary btn-sm"
          disabled={savePending || saveDisabled}
          onClick={onSave}
        >
          <LuSave className="size-4" />
          Save
        </button>
      </div>
      {children}
      {saveError ? <p className="text-error text-sm shrink-0">{saveError}</p> : null}
      {enableError ? <p className="text-error text-sm shrink-0">{enableError}</p> : null}
    </div>
  );
}

export function WorkflowNewPage() {
  const navigate = useNavigate();
  const { notify } = useNotifications();
  const [ready, setReady] = useState(() => shouldSkipNewWorkflowPreset());
  const [content, setContent] = useState(NEW_WORKFLOW_YAML);
  const [savedYaml, setSavedYaml] = useState(NEW_WORKFLOW_YAML);
  const [saveWarnings, setSaveWarnings] = useState(null);
  const create = useCreateWorkflow();

  function onSave(saveAnyway = false) {
    create.mutate(
      { owner: DEFAULT_OWNER, content, saveAnyway },
      {
        onSuccess: (data) => {
          setSaveWarnings(null);
          notify.success(`Created ${data.file}`);
          navigate(
            `/workflows/${encodeURIComponent(data.owner)}/${encodeURIComponent(data.file)}/edit`,
          );
        },
        onError: (err) => {
          if (isSaveWarningsError(err)) {
            setSaveWarnings(saveWarningsFromError(err));
            return;
          }
          notify.error(errorMessage(err));
        },
      },
    );
  }

  if (!ready) {
    return (
      <NewWorkflowPresetDialog
        onCancel={() => navigate("/workflows")}
        onChoose={(yaml) => {
          const initial = yaml == null || yaml === "" ? NEW_WORKFLOW_YAML : yaml;
          setContent(initial);
          setSavedYaml(initial);
          setReady(true);
        }}
      />
    );
  }

  return (
    <>
      <WorkflowEditorLayout
        title="New workflow"
        onSave={() => onSave(false)}
        savePending={create.isPending}
        saveError={create.isError && !saveWarnings ? errorMessage(create.error) : null}
      >
        <div className="flex min-h-0 flex-1 flex-col gap-3">
          <WorkflowVisualEditor
            yaml={content}
            onYamlChange={setContent}
            owner={DEFAULT_OWNER}
            file=""
            savedYaml={savedYaml}
            showTest={false}
          />
        </div>
      </WorkflowEditorLayout>
      {saveWarnings ? (
        <SaveWorkflowWarningsDialog
          warnings={saveWarnings}
          pending={create.isPending}
          onCancel={() => setSaveWarnings(null)}
          onSaveAnyway={() => onSave(true)}
        />
      ) : null}
    </>
  );
}

export function WorkflowEditPage() {
  const navigate = useNavigate();
  const { notify } = useNotifications();
  const { owner: rawOwner, file: rawFile } = useParams();
  const owner = decodeURIComponent(rawOwner ?? "");
  const file = decodeURIComponent(rawFile ?? "");
  const existing = useWorkflow(owner, file);
  const save = useSaveWorkflow();
  const setEnabled = useSetWorkflowEnabled();
  const [content, setContent] = useState("");
  const [savedYaml, setSavedYaml] = useState("");
  const [contentReady, setContentReady] = useState(false);
  const [testOpen, setTestOpen] = useState(false);
  const [duplicateOpen, setDuplicateOpen] = useState(false);
  const [saveWarnings, setSaveWarnings] = useState(null);
  const [previewRevision, setPreviewRevision] = useState(null);
  const [previewMeta, setPreviewMeta] = useState(null);
  const [previewBaseline, setPreviewBaseline] = useState(null);
  const [discardConfirm, setDiscardConfirm] = useState(null);
  const [savePreviewConfirm, setSavePreviewConfirm] = useState(false);
  const routeKey = `${owner}/${file}`;
  const [activeKey, setActiveKey] = useState(routeKey);
  const previewQuery = useWorkflowRevision(owner, file, previewRevision);

  if (activeKey !== routeKey) {
    setActiveKey(routeKey);
    setContent("");
    setSavedYaml("");
    setContentReady(false);
    setTestOpen(false);
    setDuplicateOpen(false);
    setPreviewRevision(null);
    setPreviewMeta(null);
    setPreviewBaseline(null);
    setDiscardConfirm(null);
    setSavePreviewConfirm(false);
  }

  useEffect(() => {
    if (existing.isLoading) return;
    if (previewRevision != null) return;
    if (!contentReady && existing.data?.content != null) {
      setContent(existing.data.content);
      setSavedYaml(existing.data.content);
      setContentReady(true);
    }
  }, [existing.data, existing.isLoading, contentReady, previewRevision]);

  useEffect(() => {
    if (previewRevision == null || previewQuery.isLoading) return;
    if (previewQuery.data?.content != null) {
      setContent(previewQuery.data.content);
      setPreviewBaseline(previewQuery.data.content);
      setPreviewMeta({ created_at: previewQuery.data.created_at });
    }
  }, [previewRevision, previewQuery.data, previewQuery.isLoading]);

  function isDirty() {
    const baseline = previewRevision != null ? previewBaseline : savedYaml;
    return contentReady && baseline != null && content !== baseline;
  }

  function exitPreview() {
    setPreviewRevision(null);
    setPreviewMeta(null);
    setPreviewBaseline(null);
    existing.refetch().then((result) => {
      const next = result.data?.content;
      if (next != null) {
        setContent(next);
        setSavedYaml(next);
      }
    });
  }

  function applySelectRevision(revision, meta) {
    if (revision == null) {
      exitPreview();
      return;
    }
    setPreviewRevision(revision);
    if (meta?.created_at) {
      setPreviewMeta({ created_at: meta.created_at });
    }
  }

  function onSelectRevision(revision, meta) {
    if (isDirty()) {
      setDiscardConfirm(() => () => applySelectRevision(revision, meta));
      return;
    }
    applySelectRevision(revision, meta);
  }

  function onBackToCurrent() {
    if (isDirty()) {
      setDiscardConfirm(() => () => exitPreview());
      return;
    }
    exitPreview();
  }

  function onReverted() {
    setPreviewRevision(null);
    setPreviewMeta(null);
    setPreviewBaseline(null);
    existing.refetch().then((result) => {
      const next = result.data?.content;
      if (next != null) {
        setContent(next);
        setSavedYaml(next);
      }
    });
  }

  function onSave(saveAnyway = false) {
    save.mutate(
      { owner, file, content, saveAnyway },
      {
        onSuccess: () => {
          setSavedYaml(content);
          setSaveWarnings(null);
          setSavePreviewConfirm(false);
          notify.success("Workflow saved");
          if (previewRevision != null) {
            setPreviewRevision(null);
            setPreviewMeta(null);
            setPreviewBaseline(null);
          }
        },
        onError: (err) => {
          if (isSaveWarningsError(err)) {
            setSaveWarnings(saveWarningsFromError(err));
            return;
          }
        },
      },
    );
  }

  function onSaveRequest() {
    const liveYaml = existing.data?.content;
    if (previewRevision != null && content !== liveYaml) {
      setSavePreviewConfirm(true);
      return;
    }
    onSave(false);
  }

  if (existing.isLoading) {
    return (
      <div className="flex min-h-[12rem] items-center justify-center">
        <span className="loading loading-spinner loading-lg" />
      </div>
    );
  }

  if (existing.isError) {
    return (
      <div className="space-y-3">
        <Link to="/workflows" className="btn btn-ghost btn-sm">
          <LuArrowLeft className="size-4" />
          Back
        </Link>
        <p className="text-error">Workflow not found</p>
      </div>
    );
  }

  const parsedDoc = parseWorkflowYaml(content);
  const yamlOk = !parsedDoc.parseError;
  const workflowName = parsedDoc.doc?.name?.trim();
  const pageTitle = workflowName ? `${workflowName}` : file;
  const isPreviewing = previewRevision != null;
  const previewLoading = isPreviewing && previewQuery.isLoading;

  return (
    <>
      <WorkflowEditorLayout
        title={
          <span className="flex min-w-0 flex-col items-start gap-0.5">
            <span className="truncate">{pageTitle}</span>
            <span className="text-xs font-normal font-mono opacity-50">{file}</span>
          </span>
        }
        savePending={save.isPending}
        saveDisabled={!contentReady || previewLoading}
        saveError={save.isError && !saveWarnings ? saveErrorMessage(save.error) : null}
        onSave={() => onSaveRequest()}
        onTest={isPreviewing ? undefined : () => setTestOpen(true)}
        onDuplicate={isPreviewing ? undefined : () => setDuplicateOpen(true)}
        onToggleEnabled={
          isPreviewing
            ? undefined
            : () =>
                setEnabled.mutate({
                  owner,
                  file,
                  enabled: existing.data?.parsed?.enabled === false,
                })
        }
        enabled={existing.data?.parsed?.enabled !== false}
        enablePending={setEnabled.isPending}
        enableDisabled={!contentReady || Boolean(existing.data?.parseError) || !yamlOk}
        enableError={setEnabled.isError ? errorMessage(setEnabled.error) : null}
      >
        <div className="flex min-h-0 flex-1 gap-3">
          <div className="flex min-h-0 min-w-0 flex-1 flex-col gap-3">
            {isPreviewing && previewMeta ? (
              <WorkflowRevisionBanner
                owner={owner}
                file={file}
                revision={previewRevision}
                createdAt={previewMeta.created_at}
                onBackToCurrent={onBackToCurrent}
                onReverted={onReverted}
              />
            ) : null}
            {previewLoading ? (
              <div className="flex min-h-[12rem] flex-1 items-center justify-center">
                <span className="loading loading-spinner loading-lg" />
              </div>
            ) : (
              <WorkflowVisualEditor
                yaml={content}
                onYamlChange={setContent}
                owner={owner}
                file={file}
                savedYaml={savedYaml}
                showTest={!isPreviewing}
                testOpen={testOpen}
                onTestClose={() => setTestOpen(false)}
              />
            )}
          </div>
          <div className="hidden w-64 shrink-0 xl:block">
            <WorkflowHistoryPanel
              owner={owner}
              file={file}
              previewRevision={previewRevision}
              onSelectRevision={onSelectRevision}
              onReverted={onReverted}
            />
          </div>
        </div>
      </WorkflowEditorLayout>
      {duplicateOpen ? (
        <DuplicateWorkflowDialog
          source={{ owner, file, key: `${owner}/${file}` }}
          warnUnsaved={contentReady && content !== savedYaml}
          onClose={() => setDuplicateOpen(false)}
          onDuplicated={(data) => {
            setDuplicateOpen(false);
            navigate(
              `/workflows/${encodeURIComponent(data.owner)}/${encodeURIComponent(data.file)}/edit`,
            );
          }}
        />
      ) : null}
      {saveWarnings ? (
        <SaveWorkflowWarningsDialog
          warnings={saveWarnings}
          pending={save.isPending}
          onCancel={() => setSaveWarnings(null)}
          onSaveAnyway={() => onSave(true)}
        />
      ) : null}
      {savePreviewConfirm ? (
        <ConfirmDialog
          open
          title="Save over current workflow?"
          message="This will replace the current live workflow with the content you are viewing."
          confirmLabel="Save"
          confirmClass="btn-primary"
          pending={save.isPending}
          onCancel={() => setSavePreviewConfirm(false)}
          onConfirm={() => onSave(false)}
        />
      ) : null}
      {discardConfirm ? (
        <ConfirmDialog
          open
          title="Discard unsaved changes?"
          message="You have unsaved edits. Switching versions will discard them."
          confirmLabel="Discard"
          confirmClass="btn-warning"
          pending={false}
          onCancel={() => setDiscardConfirm(null)}
          onConfirm={() => {
            const action = discardConfirm;
            setDiscardConfirm(null);
            action?.();
          }}
        />
      ) : null}
    </>
  );
}