"use client";

import { useRef, useState } from "react";
import type { Dispatch, SetStateAction } from "react";
import { deleteWorkflowAction } from "@/app/actions/workspaces";
import { t } from "@/lib/i18n";
import type { Workflow, WorkflowStep } from "@/lib/types/http";
import { useToast } from "@/components/toast-provider";
import { SettingsSaveCancelledError, useSettingsSaveContributor } from "./settings-save-provider";
import {
  areStepDraftsEqual,
  createWorkflowDraftSaveProgress,
  persistWorkflowDraft,
  remapWorkflowDraftSteps,
} from "./workflow-card-actions";
import type { useWorkflowMutationGuard } from "./workflow-mutation-guard";

const TEMP_WORKFLOW_PREFIX = "temp-workflow-";

function workflowSaveInvalidReason(
  workflowName: string,
  modelConfigResolutionPending: boolean,
  translate: (key: string) => string,
): string | undefined {
  if (!workflowName.trim()) return translate("workflows:workflowNameIsRequired");
  if (modelConfigResolutionPending) return translate("agents:resolvingModelOptions");
  return undefined;
}

type WorkflowSavedParams = {
  clientWorkflow: Workflow;
  submittedWorkflow: Workflow;
  savedWorkflow: Workflow;
  currentSteps: WorkflowStep[];
  savedSteps: WorkflowStep[];
  finalizeIdentity: boolean;
};

type WorkflowDraftContributorArgs = {
  workflow: Workflow;
  isWorkflowDirty: boolean;
  workflowSteps: WorkflowStep[];
  savedWorkflowSteps: WorkflowStep[];
  setWorkflowSteps: Dispatch<SetStateAction<WorkflowStep[]>>;
  setSavedWorkflowSteps: Dispatch<SetStateAction<WorkflowStep[]>>;
  mutationGuard: ReturnType<typeof useWorkflowMutationGuard>;
  toast: ReturnType<typeof useToast>["toast"];
  onWorkflowSaved: (params: WorkflowSavedParams) => void;
  onDiscardWorkflow: () => void;
  onDeleteWorkflow: () => Promise<unknown>;
  isSessionConfigResolutionPending?: boolean;
};

function useWorkflowDraftPersistence(args: WorkflowDraftContributorArgs) {
  const { workflow, workflowSteps, savedWorkflowSteps } = args;
  const latestStepsRef = useRef(workflowSteps);
  latestStepsRef.current = workflowSteps;
  const saveProgressRef = useRef(createWorkflowDraftSaveProgress());
  const saveFailedRef = useRef(false);
  const revision = JSON.stringify({
    workflow: [
      workflow.name,
      workflow.description ?? "",
      workflow.prompt ?? "",
      workflow.agent_profile_id ?? "",
    ],
    steps: workflowSteps,
  });
  const latestRevisionRef = useRef(revision);
  latestRevisionRef.current = revision;

  const persistSubmittedDraft = async (submittedRevision: string | number) => {
    let result: Awaited<ReturnType<typeof persistWorkflowDraft>>;
    try {
      result = await persistWorkflowDraft({
        workflow,
        draftSteps: workflowSteps,
        savedSteps: savedWorkflowSteps,
        progress: saveProgressRef.current,
      });
      saveFailedRef.current = false;
    } catch (error) {
      saveFailedRef.current = true;
      throw error;
    }
    const unchanged = submittedRevision === latestRevisionRef.current;
    const currentSteps = unchanged
      ? result.steps
      : remapWorkflowDraftSteps(
          latestStepsRef.current,
          result.workflow.id,
          saveProgressRef.current.stepIds,
        );
    args.setSavedWorkflowSteps(result.steps);
    args.setWorkflowSteps(currentSteps);
    args.onWorkflowSaved({
      clientWorkflow: workflow,
      submittedWorkflow: workflow,
      savedWorkflow: result.workflow,
      currentSteps,
      savedSteps: result.steps,
      finalizeIdentity: unchanged,
    });
  };

  return {
    revision,
    latestRevisionRef,
    persistSubmittedDraft,
    saveProgressRef,
    saveFailedRef,
  };
}

export function useWorkflowDraftContributor(args: WorkflowDraftContributorArgs) {
  const {
    workflow,
    workflowSteps,
    savedWorkflowSteps,
    mutationGuard,
    toast,
    isSessionConfigResolutionPending = false,
  } = args;
  const persistence = useWorkflowDraftPersistence(args);
  const removingDraftRef = useRef(false);
  const [isRemovingDraft, setIsRemovingDraft] = useState(false);
  const stepsDirty = !areStepDraftsEqual(workflowSteps, savedWorkflowSteps);

  useSettingsSaveContributor({
    id: `workflow:${workflow.id}`,
    order: 100,
    revision: persistence.revision,
    isDirty: args.isWorkflowDirty || stepsDirty,
    canSave: workflow.name.trim().length > 0 && !isSessionConfigResolutionPending,
    invalidReason: workflowSaveInvalidReason(workflow.name, isSessionConfigResolutionPending, t),
    save: async (submittedRevision) => {
      if (!workflow.id.startsWith(TEMP_WORKFLOW_PREFIX)) {
        await persistence.persistSubmittedDraft(submittedRevision);
        return;
      }
      let guardReturned = false;
      let operationStarted = false;
      await mutationGuard.guardMutation({
        baselineSteps: [],
        proposedSteps: workflowSteps,
        intent: "create",
        operation: async () => {
          operationStarted = true;
          try {
            await persistence.persistSubmittedDraft(submittedRevision);
          } catch (error) {
            if (!guardReturned) throw error;
            toast({
              title: t("workflows:failedToSaveWorkflowChanges"),
              description: error instanceof Error ? error.message : t("common:requestFailed"),
              variant: "error",
            });
          }
        },
      });
      guardReturned = true;
      if (!operationStarted) throw new SettingsSaveCancelledError();
    },
    discard: async (submittedRevision) => {
      const persistedDraft = persistence.saveProgressRef.current.workflow;
      if (workflow.id.startsWith(TEMP_WORKFLOW_PREFIX) && persistedDraft) {
        await deleteWorkflowAction(persistedDraft.id);
      } else if (persistence.saveFailedRef.current) {
        throw new Error(t("workflows:retryPartialSaveBeforeLeaving"));
      }
      if (
        submittedRevision !== undefined &&
        !Object.is(submittedRevision, persistence.latestRevisionRef.current)
      ) {
        return;
      }
      args.setWorkflowSteps(savedWorkflowSteps);
      args.onDiscardWorkflow();
    },
  });

  const removeDraftWorkflow = async () => {
    if (removingDraftRef.current) return;
    removingDraftRef.current = true;
    setIsRemovingDraft(true);
    try {
      const persistedDraft = persistence.saveProgressRef.current.workflow;
      if (workflow.id.startsWith(TEMP_WORKFLOW_PREFIX) && persistedDraft) {
        await deleteWorkflowAction(persistedDraft.id);
      }
      await args.onDeleteWorkflow();
    } finally {
      removingDraftRef.current = false;
      setIsRemovingDraft(false);
    }
  };

  return {
    hasUnsavedChanges: args.isWorkflowDirty || stepsDirty,
    removeDraftWorkflow,
    isRemovingDraft,
  };
}