middleware.ts

import { defineMiddleware, HTTPError } from 'h3'
import type { Middleware } from 'h3'

import { createSupabaseContext } from '../../create-supabase-context.js'
import type { SupabaseContext, WithSupabaseConfig } from '../../types.js'

/**
 * H3 middleware that creates a {@link SupabaseContext} and stores it in `event.context.supabaseContext`.
 *
 * Skips if a previous middleware already set the context, enabling chained middleware via `app.use()`.
 * Throws an `HTTPError` on auth failure.
 *
 * @param config - Auth modes and optional environment overrides. CORS is excluded — use H3's CORS utilities.
 * @returns An H3 middleware.
 *
 * @example App-wide auth via app.use()
 * ```ts
 * import { H3 } from 'h3'
 * import { withSupabase } from '@supabase/server/adapters/h3'
 *
 * const app = new H3()
 * app.use(withSupabase({ auth: 'user' }))
 *
 * app.get('/games', async (event) => {
 *   const { supabase } = event.context.supabaseContext
 *   return supabase.from('favorite_games').select()
 * })
 *
 * export default { fetch: app.fetch }
 * ```
 *
 * @example Per-route auth via defineHandler
 * ```ts
 * import { defineHandler } from 'h3'
 * import { withSupabase } from '@supabase/server/adapters/h3'
 *
 * export default defineHandler({
 *   middleware: [withSupabase({ auth: 'user' })],
 *   handler: async (event) => {
 *     const { supabase } = event.context.supabaseContext
 *     return supabase.from('favorite_games').select()
 *   },
 * })
 * ```
 *
 * @category Adapters
 */
export function withSupabase(
  config?: Omit<WithSupabaseConfig, 'cors'>,
): Middleware {
  return defineMiddleware(async (event, next) => {
    const context = event.context as { supabaseContext?: SupabaseContext }
    if (context.supabaseContext) return next()
    const { data: ctx, error } = await createSupabaseContext(event.req, config)
    if (error) {
      throw new HTTPError(error.message, { status: error.status, cause: error })
    }
    context.supabaseContext = ctx
    return next()
  })
}