import type { Sequelize } from "sequelize";
import { QueryTypes } from "sequelize";
import { z } from "zod/v4";

import {
  inspectResourceScopeSchema,
  resourceGlobalIntegrationClause,
  resourceScopeOwnerClause,
} from "./resource-scope-schema";

/** Pasos DDL reanudables; MariaDB no los revierte como una transacción DML. */
export const resourceScopeMigrationSteps = {
  scope:
    "ALTER TABLE resources WAIT 30 ADD COLUMN scope VARCHAR(7) CHARACTER SET ascii COLLATE ascii_bin NOT NULL DEFAULT 'company'",
  ownerCheck: `ALTER TABLE resources WAIT 30 ADD CONSTRAINT resource_scope_owner CHECK (${resourceScopeOwnerClause})`,
  integrationCheck: `ALTER TABLE resources WAIT 30 ADD CONSTRAINT resource_global_no_integration CHECK (${resourceGlobalIntegrationClause})`,
  nullableOwner:
    "ALTER TABLE resources WAIT 30 MODIFY COLUMN companyId CHAR(36) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NULL",
} as const;

async function assertMigrationPreconditions(database: Sequelize) {
  const settings = z
    .array(
      z.object({ version: z.string(), foreignKeys: z.number().int(), checks: z.number().int() })
    )
    .parse(
      await database.query(
        "SELECT VERSION() AS version,@@foreign_key_checks AS foreignKeys,@@check_constraint_checks AS checks",
        { type: QueryTypes.SELECT }
      )
    );

  if (!settings[0]?.version.startsWith("11.8.")) {
    throw new Error("Migración Resource scope ensayada exclusivamente con MariaDB 11.8.");
  }
  if (settings[0].foreignKeys !== 1 || settings[0].checks !== 1) {
    throw new Error("Migración Resource scope requiere CHECK y foreign keys activados.");
  }
  const owners = await database.query(
    "SELECT r.id FROM resources r LEFT JOIN companies c ON c.id=r.companyId WHERE r.companyId IS NOT NULL AND c.id IS NULL LIMIT 1",
    { type: QueryTypes.SELECT }
  );

  if (owners.length) {
    throw new Error("Migración Resource scope detenida: propietario huérfano.");
  }
  await assertResourceForeignKeys(database);
}

/** Invocación explícita con escrituras detenidas y backup verificado; nunca desde el arranque. */
export async function migrateResourceScope(database: Sequelize) {
  await assertMigrationPreconditions(database);
  let schema = await inspectResourceScopeSchema(database);
  const completed: string[] = [];

  if (schema.mode === "legacy") {
    await database.query(resourceScopeMigrationSteps.scope);
    completed.push("scope");
    schema = await inspectResourceScopeSchema(database);
  }
  const invalid = await database.query(
    `SELECT id FROM resources WHERE NOT (${resourceScopeOwnerClause}) OR NOT (${resourceGlobalIntegrationClause}) LIMIT 1`,
    { type: QueryTypes.SELECT }
  );

  if (invalid.length) {
    throw new Error(
      "Migración Resource scope detenida: datos de ámbito o integración inconsistentes."
    );
  }
  if (!schema.ownerCheck) {
    await database.query(resourceScopeMigrationSteps.ownerCheck);
    completed.push("ownerCheck");
  }
  if (!schema.integrationCheck) {
    await database.query(resourceScopeMigrationSteps.integrationCheck);
    completed.push("integrationCheck");
  }
  if (schema.owner.nullable === "NO") {
    await database.query(resourceScopeMigrationSteps.nullableOwner);
    completed.push("nullableOwner");
  }
  const final = await inspectResourceScopeSchema(database);

  if (final.mode !== "scoped") {
    throw new Error("Migración Resource scope incompleta; mantener el servicio detenido.");
  }
  await assertMigrationPreconditions(database);

  return { mode: final.mode, completed };
}

async function assertResourceForeignKeys(database: Sequelize) {
  const keys = z
    .array(
      z.object({
        tableName: z.string(),
        parent: z.string(),
        columnNames: z.string(),
        targets: z.string(),
        deleteRule: z.string(),
        updateRule: z.string(),
      })
    )
    .parse(
      await database.query(
        "SELECT k.TABLE_NAME AS tableName,k.REFERENCED_TABLE_NAME AS parent,GROUP_CONCAT(k.COLUMN_NAME ORDER BY k.ORDINAL_POSITION) AS columnNames,GROUP_CONCAT(k.REFERENCED_COLUMN_NAME ORDER BY k.ORDINAL_POSITION) AS targets,r.DELETE_RULE AS deleteRule,r.UPDATE_RULE AS updateRule FROM information_schema.KEY_COLUMN_USAGE k JOIN information_schema.REFERENTIAL_CONSTRAINTS r ON r.CONSTRAINT_SCHEMA=k.CONSTRAINT_SCHEMA AND r.TABLE_NAME=k.TABLE_NAME AND r.CONSTRAINT_NAME=k.CONSTRAINT_NAME WHERE k.CONSTRAINT_SCHEMA=DATABASE() AND k.REFERENCED_TABLE_SCHEMA=DATABASE() GROUP BY k.TABLE_NAME,k.CONSTRAINT_NAME,k.REFERENCED_TABLE_NAME,r.DELETE_RULE,r.UPDATE_RULE",
        { type: QueryTypes.SELECT }
      )
    );
  const tables = await database.query<{ name: string }>(
    "SELECT TABLE_NAME AS name FROM information_schema.TABLES WHERE TABLE_SCHEMA=DATABASE()",
    { type: QueryTypes.SELECT }
  );
  const expected = [
    ["resources", "companies", "companyId", "id"],
    ["resources", "resource_definitions", "templateId", "id"],
    [
      "resource_directory_domains",
      "resources",
      "resourceId,companyId,templateId",
      "id,companyId,templateId",
    ],
    [
      "resource_network_shares",
      "resources",
      "resourceId,companyId,templateId",
      "id,companyId,templateId",
    ],
    ["asset_support", "resources", "companyId,resourceId", "companyId,id"],
  ] as const;

  for (const [table, parent, columns, targets] of expected) {
    if (
      tables.some((entry) => entry.name === table) &&
      !keys.some(
        (key) =>
          key.tableName === table &&
          key.parent === parent &&
          key.columnNames === columns &&
          key.targets === targets &&
          ["RESTRICT", "NO ACTION"].includes(key.deleteRule) &&
          ["RESTRICT", "NO ACTION"].includes(key.updateRule)
      )
    ) {
      throw new Error(
        `Migración Resource scope detenida: falta FK compatible en ${table} (${columns}).`
      );
    }
  }
  const primary = await database.query<{ columnNames: string }>(
    "SELECT GROUP_CONCAT(COLUMN_NAME ORDER BY ORDINAL_POSITION) AS columnNames FROM information_schema.KEY_COLUMN_USAGE WHERE CONSTRAINT_SCHEMA=DATABASE() AND TABLE_NAME='resources' AND CONSTRAINT_NAME='PRIMARY'",
    { type: QueryTypes.SELECT }
  );

  if (primary[0]?.columnNames !== "id") {
    throw new Error("Migración Resource scope detenida: se esperaba PK Resource por id.");
  }
  const nullable = await database.query(
    "SELECT k.TABLE_NAME FROM information_schema.KEY_COLUMN_USAGE k JOIN information_schema.COLUMNS c ON c.TABLE_SCHEMA=k.TABLE_SCHEMA AND c.TABLE_NAME=k.TABLE_NAME AND c.COLUMN_NAME=k.COLUMN_NAME WHERE k.CONSTRAINT_SCHEMA=DATABASE() AND k.REFERENCED_TABLE_SCHEMA=DATABASE() AND k.REFERENCED_TABLE_NAME='resources' AND c.IS_NULLABLE='YES' AND (SELECT COUNT(*) FROM information_schema.KEY_COLUMN_USAGE p WHERE p.CONSTRAINT_SCHEMA=k.CONSTRAINT_SCHEMA AND p.TABLE_NAME=k.TABLE_NAME AND p.CONSTRAINT_NAME=k.CONSTRAINT_NAME)>1",
    { type: QueryTypes.SELECT }
  );

  if (nullable.length) {
    throw new Error(
      "Migración Resource scope detenida: componente nullable en una FK operativa compuesta."
    );
  }
}