import { defineAction } from "@agent-native/core";
import { assertAccess } from "@agent-native/core/sharing";
import { z } from "zod";

import type {
  PreviewBuilderSourceReviewRequest,
  PreviewBuilderSourceReviewResponse,
} from "../shared/api.js";
import {
  getContentDatabaseSourceSnapshotForReview,
  resolveDatabaseForSourceMutation,
} from "./_database-source-utils.js";
import {
  BUILDER_SOURCE_REVIEW_PREPARE_LIMIT,
  buildBuilderSourceReviewPayload,
  reviewPreparePriority,
  withAuthoritativeBuilderTargetRows,
} from "./prepare-builder-source-review.js";

export default defineAction({
  description:
    "Preview complete Builder CMS review diffs, including document body changes, without approving or writing anything.",
  schema: z.object({
    databaseId: z.string().optional().describe("Database ID"),
    documentId: z.string().optional().describe("Database document/page ID"),
    sourceId: z.string().optional().describe("Specific Builder source ID"),
    scope: z.enum(["selected", "all"]).optional().default("all"),
    documentIds: z
      .array(z.string())
      .max(BUILDER_SOURCE_REVIEW_PREPARE_LIMIT)
      .optional()
      .describe("Optional selected document IDs that bound the preview"),
  }),
  http: { method: "GET" },
  readOnly: true,
  run: async (
    args: PreviewBuilderSourceReviewRequest,
  ): Promise<PreviewBuilderSourceReviewResponse> => {
    const database = await resolveDatabaseForSourceMutation(args);
    if (!database) throw new Error("Database not found.");
    await assertAccess("document", database.documentId, "editor");

    const selectedDocumentIds = new Set(args.documentIds ?? []);
    if (args.scope === "selected" && selectedDocumentIds.size === 0) {
      throw new Error("Select at least one Builder row before reviewing it.");
    }

    const source = await getContentDatabaseSourceSnapshotForReview(
      database,
      args.sourceId,
      args.scope === "selected" ? args.documentIds : undefined,
    );
    if (!source || source.sourceType !== "builder-cms") {
      throw new Error("Attach a Builder CMS source before reviewing updates.");
    }

    const allReviewableChanges = source.changeSets.filter((changeSet) => {
      if (
        changeSet.direction !== "outbound" ||
        (changeSet.state !== "pending_push" &&
          changeSet.state !== "staged_revision" &&
          changeSet.state !== "approved")
      ) {
        return false;
      }
      return (
        args.scope === "all" ||
        (!!changeSet.documentId &&
          selectedDocumentIds.has(changeSet.documentId))
      );
    });
    const changeSets = [...allReviewableChanges]
      .sort(
        (left, right) =>
          reviewPreparePriority(left, source) -
          reviewPreparePriority(right, source),
      )
      .slice(0, BUILDER_SOURCE_REVIEW_PREPARE_LIMIT);
    const authoritativeSource = await withAuthoritativeBuilderTargetRows({
      source,
      changeSets,
    });
    const review =
      changeSets.length > 0
        ? buildBuilderSourceReviewPayload({
            source: authoritativeSource,
            changeSets,
          })
        : null;
    if (review) {
      review.totalRowCount = allReviewableChanges.length;
      review.preparedRowLimit = changeSets.length;
    }

    return {
      sourceId: source.id,
      sourceTable: source.sourceTable,
      changeSetIds: changeSets.map((changeSet) => changeSet.id),
      review,
    };
  },
});