import { literal, safeSql, type SafeSqlFragment } from '@supabase/pg-meta/src/pg-format'
import { useQuery } from '@tanstack/react-query'
import { z } from 'zod'

import { databaseKeys } from './keys'
import { filterProtectedSchemaIndexAdvisorResult } from '@/components/interfaces/QueryPerformance/IndexAdvisor/index-advisor.utils'
import { executeSql } from '@/data/sql/execute-sql-mutation'
import type { ResponseError, UseCustomQueryOptions } from '@/types'

export type GetIndexAdvisorResultVariables = {
  projectRef?: string
  connectionString?: string | null
  query: string
}

const IndexAdvisorResultSchema = z.object({
  errors: z.array(z.string()),
  index_statements: z.array(z.string()),
  startup_cost_before: z
    .number()
    .nullable()
    .transform((v) => v ?? 0),
  startup_cost_after: z
    .number()
    .nullable()
    .transform((v) => v ?? 0),
  total_cost_before: z
    .number()
    .nullable()
    .transform((v) => v ?? 0),
  total_cost_after: z
    .number()
    .nullable()
    .transform((v) => v ?? 0),
})

export type GetIndexAdvisorResultResponse = z.infer<typeof IndexAdvisorResultSchema> & {
  index_statements: SafeSqlFragment[]
}

function markDatabaseSqlSafe(
  indexAdvisorResult: z.infer<typeof IndexAdvisorResultSchema>
): GetIndexAdvisorResultResponse {
  return indexAdvisorResult as GetIndexAdvisorResultResponse
}

export async function getIndexAdvisorResult({
  projectRef,
  connectionString,
  query,
}: GetIndexAdvisorResultVariables) {
  if (!projectRef) throw new Error('Project ref is required')

  const { result: results } = await executeSql({
    projectRef,
    connectionString,
    sql: safeSql`set search_path to public, extensions; select * from index_advisor(${literal(query)});`,
  })

  if (!results || results.length === 0) {
    console.error('[index_advisor > getIndexAdvisorResult] No results from index_advisor')
    return null
  }

  const parsed = IndexAdvisorResultSchema.safeParse(results[0])
  if (!parsed.success) {
    const firstError = parsed.error.errors[0]
    const errorPath = firstError.path.length > 0 ? ` at path: ${firstError.path.join('.')}` : ''
    console.error(
      `Invalid index advisor response${errorPath}: ${firstError.message}. Received: ${JSON.stringify(results[0])}`
    )
    return null
  }

  return filterProtectedSchemaIndexAdvisorResult(markDatabaseSqlSafe(parsed.data))
}

export type GetIndexAdvisorResultData = Awaited<ReturnType<typeof getIndexAdvisorResult>>
export type GetIndexAdvisorResultError = ResponseError

export const useGetIndexAdvisorResult = <TData = GetIndexAdvisorResultData>(
  { projectRef, connectionString, query }: GetIndexAdvisorResultVariables,
  {
    enabled = true,
    ...options
  }: UseCustomQueryOptions<GetIndexAdvisorResultData, GetIndexAdvisorResultError, TData> = {}
) => {
  const formattedQuery = (query ?? '').trim().toLowerCase()
  const isValidQueryForIndexing =
    formattedQuery.startsWith('select') || formattedQuery.startsWith('with pgrst_source')

  return useQuery<GetIndexAdvisorResultData, GetIndexAdvisorResultError, TData>({
    queryKey: databaseKeys.indexAdvisorFromQuery(projectRef, query),
    queryFn: () => getIndexAdvisorResult({ projectRef, connectionString, query }),
    retry: false,
    enabled:
      enabled &&
      typeof projectRef !== 'undefined' &&
      typeof query !== 'undefined' &&
      isValidQueryForIndexing,
    ...options,
  })
}