/** Read the world config at every run boundary. All real requests retain the host proxy transport. */
import { AgentDoc, defineExtension, GenerationTask, hook } from '@earendil-works/pi-durable'
import { CONFIG, definitionRuns, parseConfig, toolsFor } from '../core/agents.ts'
import { ModelsApi, Pin, Profile } from './api.ts'

export const order = -200
export default function models(host: any) {
  const read = async (_cwd: string) => {
    const config = parseConfig(await host.fs.read(CONFIG))
    return {...config, definitions:config.definitions.map((definition: any)=>({...definition,
      resident:definition.name === config.standing || definition.resident,
      runs:definitionRuns(definition)})), errors:[], replaced:[]}
  }
  const register = (ref: any) => {
    const store = host.models()
    if (store.getModel(ref.provider, ref.modelId)) return
    const transport = store.getProvider(ref.provider)
    const template = store.getModels(ref.provider)[0]
    if (!transport || !template) throw new Error(`No proxy transport for ${ref.provider}/${ref.modelId}`)
    const prior = store.getModels(ref.provider)
    store.setProvider({...transport, getModels:()=>[...prior, {...template, id:ref.modelId, name:ref.modelId,
      cost:{input:0,output:0,cacheRead:0,cacheWrite:0}}]})
  }
  const apply = async (tx: any, id: number) => {
    const state = await tx.doc(AgentDoc, id)
    const profile = await tx.doc(Profile, id)
    const config = await read(state.cwd ?? '/')
    if (profile.standing) profile.agent = config.standing
    const definition = profile.agent ? config.definitions.find(d => d.name === profile.agent) : undefined
    if (profile.agent && !definition) throw new Error(`Unknown agent ${profile.agent}: ${JSON.stringify(config.errors)}`)
    const selected = (definition ?? config.definitions.find((d: any)=>d.name === config.standing)).runs
    const pinned = await host.want(Pin)?.pin(tx, id)
    const ref = pinned ?? profile.model ?? selected.model
    register(ref)
    state.model = ref
    if (profile.thinking ?? selected.thinking) state.thinkingLevel = profile.thinking ?? selected.thinking
    else delete state.thinkingLevel
    state.instructions = [config.prompt, definition ? `You are @${definition.name}.\n\n${definition.instructions}` : ''].filter(Boolean).join('\n\n')
    if (definition) {
      if (profile.inheritedTools === undefined) profile.inheritedTools = state.tools ?? null
      const inherited = profile.inheritedTools
      if (definition.tools || Array.isArray(inherited)) state.tools = toolsFor(definition,inherited ?? []).filter(name=>!profile.excludeTools?.includes(name))
      else state.tools = {remove:[...new Set([...(inherited?.remove ?? []),...(definition.denyTools ?? []),...(profile.excludeTools ?? [])])]}
    }
    return ref
  }
  host.implement(ModelsApi, {
    discover: read,
    configure: async (tx: any, id: number, options: any) => {
      const profile = await tx.doc(Profile,id)
      profile.agent = options.agent
      profile.standing = options.standing ?? false
      profile.inheritedTools = options.inheritedTools
      profile.excludeTools = options.excludeTools ?? []
      if (options.model) profile.model = options.model
      else delete profile.model
      if (options.thinking) profile.thinking = options.thinking
      else delete profile.thinking
      return apply(tx,id)
    },
    resolve: apply,
    start: async ({agent, cwd, ownership = {kind:'ownerless'}}: any, context: any) => {
      const conversation = await host.harness().createConversation({ownership, agent:{cwd}, init:async (tx: any, id: number)=>{
        (await tx.doc(Profile,id)).agent = agent
        await apply(tx,id)
      }}, context)
      return conversation
    },
  })
  return defineExtension({name:'models', hooks:[hook(GenerationTask,{beforeInput:async (_input, {tx,conversationId})=>{await apply(tx,conversationId)}})]})
}