/*
Copyright 2023-2024 SolarWinds Worldwide, LLC.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import { type SpanContext } from "@opentelemetry/api"

import { type SwConfiguration } from "."

export interface SpanCache {
  txname?: string
  txnameCustom?: string
  parentId?: string
  parentRemote?: boolean
}

class Cache {
  private readonly spanCache = new Map<string, SpanCache>()

  get(ctx: SpanContext): SpanCache | undefined {
    return this.spanCache.get(Cache.key(ctx))
  }

  getOrInit(ctx: SpanContext, init: SpanCache = {}): SpanCache {
    const k = Cache.key(ctx)
    let c = this.spanCache.get(k)
    if (!c) {
      c = init
      this.spanCache.set(k, c)
    }
    return c
  }

  getEntry(ctx: SpanContext): SpanCache | undefined {
    for (;;) {
      const c = this.get(ctx)

      if (!c) return undefined
      if (!c.parentId || c.parentRemote) return c

      ctx = { ...ctx, traceId: ctx.traceId, spanId: c.parentId }
    }
  }

  getTxname(ctx: SpanContext, config: SwConfiguration): string | undefined {
    const c = this.get(ctx)
    return c?.txnameCustom ?? config.transactionName ?? c?.txname
  }

  clear(ctx: SpanContext): void {
    this.spanCache.delete(Cache.key(ctx))
  }

  private static key(ctx: SpanContext): string {
    return `${ctx.traceId}-${ctx.spanId}`
  }
}
export const cache = new Cache()