/** Resolve world families and definitions at each run boundary. All real requests retain the host proxy transport. */
import { AgentDoc, defineExtension, GenerationTask, hook } from '@earendil-works/pi-durable'
import { definitionRuns, discoverAgents, parseDefinition, parseOverlay, parseFamilies, parseFrontmatter, toolsFor } from '../core/agents.ts'
import { ModelsApi, Pin, Profile } from './api.ts'
import { repoRoot } from './files.ts'
export const order = -200
export default function models(host: any) {
  const read = async (cwd: string) => {
    const families = parseFamilies(await host.fs.read('/src/sausage/agents/models.json'))
    const root = await repoRoot(host.fs, cwd)
    const files = []
    for (const folder of ['/src/sausage/agents', `${root}/.sausage/agents`]) {
      let entries
      try { entries = await host.fs.list(folder) } catch (error) { if (error.code !== 'not_found') throw error; entries = [] }
      for (const entry of entries) if (entry.kind === 'file' && entry.name.endsWith('.md')) {
        const path = `${folder}/${entry.name}`
        files.push({path, text:await host.fs.read(path)})
      }
    }
    const refs = Object.values(families).map(spec => spec.model.replace(/:(off|minimal|low|medium|high|xhigh|max)$/, ''))
    // Explicit pins can name a proxy model outside the families.
    for (const file of files) {
      try {
        const parsed = 'addTools' in parseFrontmatter(file.text).frontmatter ? parseOverlay(file.text,file.path).settings : parseDefinition(file.text,file.path)
        if (parsed.model) refs.push(parsed.model.replace(/:(off|minimal|low|medium|high|xhigh|max)$/, ''))
      } catch { /* discoverAgents records invalid files without replacing valid definitions. */ }
    }
    const found = discoverAgents(files, '/src/sausage', root, families, refs)
    return {families, ...found}
  }
  const transport = host.models().getProvider('openai')
  const template = host.models().getModels('openai')[0]
  const register = (ref: any) => {
    const store = host.models()
    if (store.getModel(ref.provider, ref.modelId)) return
    if (!transport || !template) throw new Error(`No proxy transport for ${ref.provider}/${ref.modelId}`)
    const prior = store.getModels(ref.provider)
    store.setProvider({...transport, id:ref.provider, getModels:()=>[...prior, {...template, provider:ref.provider, id:ref.modelId, name:ref.modelId}]})
  }
  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 ?? '/')
    const definition = profile.agent ? config.definitions.find(d => d.name === profile.agent) : undefined
    if (profile.agent && !definition) throw new Error(`Unknown agent ${profile.agent}: ${JSON.stringify(config.errors)}`)
    const selected = definition?.runs ?? definitionRuns({} as any,config.families,Object.values(config.families).map(spec=>spec.model.replace(/:(off|minimal|low|medium|high|xhigh|max)$/, '')))
    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
    if (definition) {
      state.instructions = definition.instructions
      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.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)}})]})
}