import {
  type Dispatch,
  type SetStateAction,
  useCallback,
  useMemo,
  useRef,
  useState,
} from 'react';

import type {
  CanvasGenerationDialogState,
  GenerateDialogState,
} from './ImageCanvasEditorTypes';
import { isCanvasGenerationDialog } from './ImageCanvasGenerationModel';

type CanvasGenerationDialogUpdater = (
  dialog: CanvasGenerationDialogState,
) => CanvasGenerationDialogState | null;

export type CanvasGenerationDialogDraft = Omit<
  CanvasGenerationDialogState,
  'id'
> & {
  id?: string;
};

/**
 * 中文注释：删除生成占位前是否需要二次确认。
 *
 * 确认弹窗讲的是「已消耗的泥点不会返还」，只对计费生成成立。完美像素
 * `generation_cost_mud_points = 0`，删除占位也不撤销任何在途请求——它没有取消接口，结果照常
 * 落库并进素材库，服务端 completion 发现 dialog 已不在会返回 DialogMissing 并由客户端提示。
 * 所以完美像素占位在任何状态都直接删，不额外解释。
 *
 * 判据必须看 `perfectPixelOperationId` 而**不是** `perfectPixelOperation`：后者要到源图解析 /
 * 直传完成后才写入，那一段预算最长 90 秒（未登记的本地图片要走 ticket → PUT → confirm），
 * 期间占位是 `generating` 且没有账本，按账本判会让用户删一个免费操作时看到「已消耗的泥点
 * 不会返还」。marker 在占位创建那一刻就写上，覆盖完整生命周期。
 *
 * 更一般地：这里问的是「**这次生成计不计费**」，账本的有无只是它在某一段时间内的代理。
 * 用短寿命字段的存在性去判断长期属性，正是本仓库反复出错的形状。
 */
export function requiresGenerationDeleteConfirmation(
  dialog: CanvasGenerationDialogState,
) {
  return dialog.status === 'generating' && !dialog.perfectPixelOperationId;
}

function withGenerationTimestamps<T extends GenerateDialogState | null>(
  nextDialog: T,
  previousDialog?: GenerateDialogState | null,
): T {
  if (!nextDialog) {
    return nextDialog;
  }
  if (nextDialog.status !== 'generating') {
    const shouldMarkFinished =
      nextDialog.status === 'failed' || Boolean(nextDialog.generatedLayerId);
    return {
      ...nextDialog,
      generationFinishedAt: shouldMarkFinished
        ? (nextDialog.generationFinishedAt ??
          previousDialog?.generationFinishedAt ??
          Date.now())
        : nextDialog.generationFinishedAt,
    };
  }
  return {
    ...nextDialog,
    generationStartedAt:
      nextDialog.generationStartedAt ??
      previousDialog?.generationStartedAt ??
      Date.now(),
    generationFinishedAt: undefined,
  };
}

function generationDialogContextId(dialog: GenerateDialogState | null) {
  if (!dialog) {
    return null;
  }
  return isCanvasGenerationDialog(dialog)
    ? dialog.id
    : `${dialog.mode}:${dialog.sourceLayerId ?? 'draft'}`;
}

export function useCanvasGenerationDialogs({
  onActivate,
  isContextMutationLocked,
  onContextMutationRejected,
}: {
  onActivate?: () => void;
  isContextMutationLocked?: () => boolean;
  onContextMutationRejected?: () => void;
} = {}) {
  const generationDialogCounterRef = useRef(0);
  const generateDialogRef = useRef<GenerateDialogState | null>(null);
  const inactiveGenerateDialogsRef = useRef<CanvasGenerationDialogState[]>([]);
  const [generateDialog, setGenerateDialogState] =
    useState<GenerateDialogState | null>(null);
  const [inactiveGenerateDialogs, setInactiveGenerateDialogs] = useState<
    CanvasGenerationDialogState[]
  >([]);

  generateDialogRef.current = generateDialog;
  inactiveGenerateDialogsRef.current = inactiveGenerateDialogs;

  const activeCanvasGenerationDialog = isCanvasGenerationDialog(generateDialog)
    ? generateDialog
    : null;

  const rejectContextMutation = useCallback(() => {
    if (!isContextMutationLocked?.()) {
      return false;
    }
    onContextMutationRejected?.();
    return true;
  }, [isContextMutationLocked, onContextMutationRejected]);

  const setGenerateDialog = useCallback<
    Dispatch<SetStateAction<GenerateDialogState | null>>
  >(
    (nextDialogOrUpdater) => {
      const currentDialog = generateDialogRef.current;
      const nextDialog =
        typeof nextDialogOrUpdater === 'function'
          ? nextDialogOrUpdater(currentDialog)
          : nextDialogOrUpdater;
      const nextDialogWithTimestamps = withGenerationTimestamps(
        nextDialog,
        currentDialog,
      );
      const currentContextId = generationDialogContextId(currentDialog);
      const nextContextId = generationDialogContextId(nextDialogWithTimestamps);
      if (currentContextId !== nextContextId && rejectContextMutation()) {
        return;
      }
      generateDialogRef.current = nextDialogWithTimestamps;
      setGenerateDialogState(nextDialogWithTimestamps);
    },
    [rejectContextMutation],
  );
  const canvasGenerationDialogs = useMemo(
    () =>
      activeCanvasGenerationDialog
        ? [...inactiveGenerateDialogs, activeCanvasGenerationDialog]
        : inactiveGenerateDialogs,
    [activeCanvasGenerationDialog, inactiveGenerateDialogs],
  );

  const getCanvasGenerationDialogsSnapshot = useCallback(() => {
    const currentDialog = generateDialogRef.current;
    return [
      ...inactiveGenerateDialogsRef.current,
      ...(isCanvasGenerationDialog(currentDialog) ? [currentDialog] : []),
    ];
  }, []);

  const createGenerationDialogId = useCallback(() => {
    generationDialogCounterRef.current += 1;
    return `generation-dialog-${generationDialogCounterRef.current}`;
  }, []);

  const archiveActiveCanvasGenerationDialog = useCallback(() => {
    const currentDialog = generateDialogRef.current;
    if (!isCanvasGenerationDialog(currentDialog)) {
      return;
    }
    if (rejectContextMutation()) {
      return;
    }
    const nextInactiveDialogs = inactiveGenerateDialogsRef.current.some(
      (dialog) => dialog.id === currentDialog.id,
    )
      ? inactiveGenerateDialogsRef.current
      : [
          ...inactiveGenerateDialogsRef.current,
          {
            ...currentDialog,
            composerOpen: false,
          },
        ];
    inactiveGenerateDialogsRef.current = nextInactiveDialogs;
    setInactiveGenerateDialogs(nextInactiveDialogs);
  }, [rejectContextMutation]);

  const openCanvasGenerationDialog = useCallback(
    (dialog: CanvasGenerationDialogDraft) => {
      const currentDialog = generateDialogRef.current;
      if (rejectContextMutation()) {
        return isCanvasGenerationDialog(currentDialog) ? currentDialog.id : '';
      }
      if (isCanvasGenerationDialog(currentDialog)) {
        inactiveGenerateDialogsRef.current =
          inactiveGenerateDialogsRef.current.some(
            (existingDialog) => existingDialog.id === currentDialog.id,
          )
            ? inactiveGenerateDialogsRef.current
            : [
                ...inactiveGenerateDialogsRef.current,
                {
                  ...currentDialog,
                  composerOpen: false,
                },
              ];
      }
      archiveActiveCanvasGenerationDialog();
      const requestedId = dialog.id?.trim();
      const requestedIdAlreadyExists =
        Boolean(requestedId) &&
        getCanvasGenerationDialogsSnapshot().some(
          (existingDialog) => existingDialog.id === requestedId,
        );
      const id =
        requestedId && !requestedIdAlreadyExists
          ? requestedId
          : createGenerationDialogId();
      const { id: _requestedId, ...dialogWithoutId } = dialog;
      const nextDialog = withGenerationTimestamps({
        ...dialogWithoutId,
        id,
      });
      generateDialogRef.current = nextDialog;
      setGenerateDialogState(nextDialog);
      return id;
    },
    [
      archiveActiveCanvasGenerationDialog,
      createGenerationDialogId,
      getCanvasGenerationDialogsSnapshot,
      rejectContextMutation,
    ],
  );

  const updateCanvasGenerationDialogById = useCallback(
    (dialogId: string, updater: CanvasGenerationDialogUpdater) => {
      const currentDialogRef = generateDialogRef.current;
      if (
        isCanvasGenerationDialog(currentDialogRef) &&
        currentDialogRef.id === dialogId &&
        updater(currentDialogRef) === null &&
        rejectContextMutation()
      ) {
        return;
      }
      if (
        isCanvasGenerationDialog(currentDialogRef) &&
        currentDialogRef.id === dialogId
      ) {
        generateDialogRef.current = withGenerationTimestamps(
          updater(currentDialogRef),
          currentDialogRef,
        );
      }
      inactiveGenerateDialogsRef.current =
        inactiveGenerateDialogsRef.current.flatMap((dialog) => {
          if (dialog.id !== dialogId) {
            return [dialog];
          }
          const nextDialog = withGenerationTimestamps(updater(dialog), dialog);
          return nextDialog ? [nextDialog] : [];
        });
      setGenerateDialogState((currentDialog) => {
        if (
          !isCanvasGenerationDialog(currentDialog) ||
          currentDialog.id !== dialogId
        ) {
          return currentDialog;
        }
        return withGenerationTimestamps(updater(currentDialog), currentDialog);
      });
      setInactiveGenerateDialogs((currentDialogs) =>
        currentDialogs.flatMap((dialog) => {
          if (dialog.id !== dialogId) {
            return [dialog];
          }
          const nextDialog = withGenerationTimestamps(updater(dialog), dialog);
          return nextDialog ? [nextDialog] : [];
        }),
      );
    },
    [rejectContextMutation],
  );

  // 中文注释：低层删除不再对未收口的完美像素 operation 抗命。删除占位不撤销任何在途请求
  // ——完美像素没有取消接口，结果照常落库并进素材库，服务端 completion 发现 dialog 已不在
  // 会返回 DialogMissing，客户端有对应提示。封锁换来的只是「结果自动回填画布」这一便利，
  // 代价却是用户画布上出现删不掉的对象；低层偷偷保留还会让上层写出伪历史。
  const removeCanvasGenerationDialogById = useCallback(
    (dialogId: string) => {
      updateCanvasGenerationDialogById(dialogId, () => null);
    },
    [updateCanvasGenerationDialogById],
  );

  const hasCanvasGenerationDialogById = useCallback((dialogId: string) => {
    const currentDialog = generateDialogRef.current;
    return [
      ...(isCanvasGenerationDialog(currentDialog) ? [currentDialog] : []),
      ...inactiveGenerateDialogsRef.current,
    ].some((dialog) => dialog.id === dialogId);
  }, []);

  const getCanvasGenerationDialogById = useCallback((dialogId: string) => {
    const currentDialog = generateDialogRef.current;
    if (
      isCanvasGenerationDialog(currentDialog) &&
      currentDialog.id === dialogId
    ) {
      return currentDialog;
    }
    return inactiveGenerateDialogsRef.current.find(
      (dialog) => dialog.id === dialogId,
    );
  }, []);

  const activateCanvasGenerationDialog = useCallback(
    (targetDialog: CanvasGenerationDialogState) => {
      const currentDialog = generateDialogRef.current;
      if (
        (!isCanvasGenerationDialog(currentDialog) ||
          currentDialog.id !== targetDialog.id) &&
        rejectContextMutation()
      ) {
        return;
      }
      const nextInactiveDialogs = inactiveGenerateDialogsRef.current.filter(
        (dialog) => dialog.id !== targetDialog.id,
      );
      if (
        isCanvasGenerationDialog(currentDialog) &&
        currentDialog.id !== targetDialog.id
      ) {
        nextInactiveDialogs.push({
          ...currentDialog,
          composerOpen: false,
        });
      }
      const nextActiveDialog = {
        ...targetDialog,
        composerOpen: true,
      };
      inactiveGenerateDialogsRef.current = nextInactiveDialogs;
      generateDialogRef.current = nextActiveDialog;
      setInactiveGenerateDialogs(nextInactiveDialogs);
      setGenerateDialogState(nextActiveDialog);
      onActivate?.();
    },
    [onActivate, rejectContextMutation],
  );

  const restoreCanvasGenerationDialogs = useCallback(
    (dialogs: CanvasGenerationDialogState[]) => {
      const nextCounter = dialogs.reduce((maxCounter, dialog) => {
        const match = /^generation-dialog-(\d+)$/u.exec(dialog.id);
        const numericId = match ? Number.parseInt(match[1] ?? '0', 10) : 0;
        return Math.max(maxCounter, Number.isFinite(numericId) ? numericId : 0);
      }, 0);
      generationDialogCounterRef.current = Math.max(
        generationDialogCounterRef.current,
        nextCounter,
      );
      const activeDialog =
        [...dialogs]
          .reverse()
          .find((dialog) => dialog.composerOpen !== false) ??
        dialogs[dialogs.length - 1] ??
        null;
      const nextActiveDialog = activeDialog
        ? {
            ...activeDialog,
            composerOpen: activeDialog.composerOpen !== false,
          }
        : null;
      const nextInactiveDialogs = dialogs
        .filter((dialog) => dialog.id !== activeDialog?.id)
        .map((dialog) => ({
          ...dialog,
          composerOpen: false,
        }));
      generateDialogRef.current = nextActiveDialog;
      inactiveGenerateDialogsRef.current = nextInactiveDialogs;
      setGenerateDialogState(nextActiveDialog);
      setInactiveGenerateDialogs(nextInactiveDialogs);
    },
    [],
  );

  const removeCanvasGenerationDialogsByLayerId = useCallback(
    (targetLayerId: string) => {
      const keepDialog = (dialog: CanvasGenerationDialogState) =>
        dialog.sourceLayerId !== targetLayerId &&
        dialog.generatedLayerId !== targetLayerId;
      const currentDialog = generateDialogRef.current;
      if (
        isCanvasGenerationDialog(currentDialog) &&
        !keepDialog(currentDialog) &&
        rejectContextMutation()
      ) {
        return;
      }
      const nextActiveDialog =
        isCanvasGenerationDialog(currentDialog) && !keepDialog(currentDialog)
          ? null
          : currentDialog;
      const nextInactiveDialogs =
        inactiveGenerateDialogsRef.current.filter(keepDialog);
      generateDialogRef.current = nextActiveDialog;
      inactiveGenerateDialogsRef.current = nextInactiveDialogs;
      setGenerateDialogState(nextActiveDialog);
      setInactiveGenerateDialogs(nextInactiveDialogs);
    },
    [rejectContextMutation],
  );

  const getGeneratingDialogPlaceholder = useCallback(
    (dialog: GenerateDialogState) => {
      const currentDialog = generateDialogRef.current;
      if (dialog.id) {
        const latestDialog = [
          ...(isCanvasGenerationDialog(currentDialog) ? [currentDialog] : []),
          ...inactiveGenerateDialogsRef.current,
        ].find((candidateDialog) => candidateDialog.id === dialog.id);
        if (latestDialog?.status === 'generating') {
          return latestDialog.placeholder ?? dialog.placeholder;
        }
      }
      if (
        currentDialog?.mode === dialog.mode &&
        (!dialog.id || currentDialog.id === dialog.id) &&
        currentDialog.status === 'generating'
      ) {
        return currentDialog.placeholder ?? dialog.placeholder;
      }
      return dialog.placeholder;
    },
    [],
  );

  return {
    generateDialog,
    setGenerateDialog,
    generateDialogRef,
    inactiveGenerateDialogs,
    setInactiveGenerateDialogs,
    inactiveGenerateDialogsRef,
    activeCanvasGenerationDialog,
    canvasGenerationDialogs,
    getCanvasGenerationDialogsSnapshot,
    archiveActiveCanvasGenerationDialog,
    openCanvasGenerationDialog,
    updateCanvasGenerationDialogById,
    removeCanvasGenerationDialogById,
    hasCanvasGenerationDialogById,
    getCanvasGenerationDialogById,
    activateCanvasGenerationDialog,
    restoreCanvasGenerationDialogs,
    removeCanvasGenerationDialogsByLayerId,
    getGeneratingDialogPlaceholder,
  };
}