// Agent personas — named, role-scoped sub-system prompts.
// Each persona stacks on top of the main systemPrompt to specialize the
// assistant for a task. Persisted in localStorage; reactive across tabs.

import { useEffect, useSyncExternalStore } from "react"

export type Agent = {
  id: string
  name: string
  role: string
  prompt: string
}

export const DEFAULT_AGENTS: Agent[] = [
  {
    id: "operator",
    name: "Atlas",
    role: "Platform Operator",
    prompt:
      "You're the platform admin's day-to-day operator inside Arcadia Admin. Treat the signed-in user as a senior platform administrator running a multi-tenant Arcadia deployment. Default to action: when the user asks about live data, call a tool; when they ask to do something, suggest the tool call and ask for confirmation if it's a write. Prefer tenant slugs over UUIDs in conversation. Keep replies tight — operators read fast.",
  },
  {
    id: "auditor",
    name: "Notary",
    role: "Auditor",
    prompt:
      "You're an audit-focused assistant inside Arcadia Admin. Specialise in audit logs, access reviews, and 'who did what when' questions. Always cite the actor_type (user / platform_admin / api_key / system) and timestamp when summarising audit entries. Be cautious about claims you can't back with a tool result — call a tool first.",
  },
  {
    id: "triage",
    name: "Tracer",
    role: "Incident Triage",
    prompt:
      "You're an incident-triage assistant inside Arcadia Admin. When the user reports a problem (a tenant member can't sign in, a billing call is 402'ing, a webhook is failing), walk the diagnostic tree: identify the tenant, check tenant status, check the user's roles, check the billing-config / api-metering / feature-flag overrides as relevant. Suggest impersonation only when it's the right escalation. Keep a clear hypothesis → check → result rhythm.",
  },
  {
    id: "analyst",
    name: "Census",
    role: "Platform Analyst",
    prompt:
      "You're an analyst inside Arcadia Admin. Answer numerical and aggregate questions across the platform: tenant counts by status, plan distribution, audit-log volume, growth. Always pull live data via tools — never guess from stale snapshots. Present findings in plain prose first, then a small table when the breakdown helps.",
  },
  {
    id: "ui-driver",
    name: "Pilot",
    role: "UI Operator",
    prompt:
      "You specialise in driving Arcadia Admin's UI on the operator's behalf. Prefer doing over explaining. When the user asks for an action that maps to a UI element, emit an action block immediately (using `data-action` ids the host has documented). For data questions, prefer tool calls over UI navigation.",
  },
]

const STORAGE_KEY = "crema.agents"
const ACTIVE_KEY = "crema.assistant.activeAgent"
const CHANGE_EVENT = "crema:agents-change"

function isAgent(v: unknown): v is Agent {
  return (
    !!v &&
    typeof v === "object" &&
    typeof (v as Agent).id === "string" &&
    typeof (v as Agent).name === "string" &&
    typeof (v as Agent).role === "string" &&
    typeof (v as Agent).prompt === "string"
  )
}

// Old Vibespace agent ids — used to auto-migrate operators stuck on the
// generic defaults from before Arcadia Admin had its own personas.
const LEGACY_AGENT_IDS = new Set(["generalist", "coder", "writer", "researcher"])

// Retired arcadia-era persona names. If we see any of these in storage, the
// operator hasn't customised their roster — re-seed with the current names
// so a rename in DEFAULT_AGENTS actually reaches the UI.
const RETIRED_AGENT_NAMES = new Set(["Ledger", "Beacon", "Tally", "Cursor"])

function isLegacyDefaultSet(agents: Agent[]): boolean {
  return (
    agents.some((a) => LEGACY_AGENT_IDS.has(a.id)) ||
    agents.some((a) => RETIRED_AGENT_NAMES.has(a.name))
  )
}

function readFromStorage(): Agent[] {
  if (typeof window === "undefined") return DEFAULT_AGENTS
  try {
    const raw = localStorage.getItem(STORAGE_KEY)
    if (!raw) return DEFAULT_AGENTS
    const parsed = JSON.parse(raw)
    if (!Array.isArray(parsed)) return DEFAULT_AGENTS
    const cleaned = parsed.filter(isAgent)
    if (cleaned.length === 0) return DEFAULT_AGENTS
    if (isLegacyDefaultSet(cleaned)) {
      // Auto-migrate: stored set still contains pre-arcadia personas.
      localStorage.setItem(STORAGE_KEY, JSON.stringify(DEFAULT_AGENTS))
      localStorage.removeItem(ACTIVE_KEY)
      return DEFAULT_AGENTS
    }
    return cleaned
  } catch {
    return DEFAULT_AGENTS
  }
}

export function loadAgents(): Agent[] {
  return readFromStorage()
}

export function saveAgents(next: Agent[]) {
  if (typeof window === "undefined") return
  localStorage.setItem(STORAGE_KEY, JSON.stringify(next))
  window.dispatchEvent(new CustomEvent(CHANGE_EVENT))
}

export function resetAgents() {
  saveAgents(DEFAULT_AGENTS)
}

let cached: Agent[] | null = null

function subscribe(cb: () => void): () => void {
  const onChange = () => {
    cached = null
    cb()
  }
  window.addEventListener(CHANGE_EVENT, onChange)
  window.addEventListener("storage", (e) => {
    if (e.key === STORAGE_KEY || e.key === ACTIVE_KEY) onChange()
  })
  return () => {
    window.removeEventListener(CHANGE_EVENT, onChange)
  }
}

function getSnapshot(): Agent[] {
  if (!cached) cached = readFromStorage()
  return cached
}

function getServerSnapshot(): Agent[] {
  return DEFAULT_AGENTS
}

export function useAgents(): Agent[] {
  const value = useSyncExternalStore(subscribe, getSnapshot, getServerSnapshot)
  useEffect(() => {
    cached = null
  }, [])
  return value
}

export function loadActiveAgentId(): string {
  if (typeof window === "undefined") return DEFAULT_AGENTS[0].id
  try {
    return localStorage.getItem(ACTIVE_KEY) ?? DEFAULT_AGENTS[0].id
  } catch {
    return DEFAULT_AGENTS[0].id
  }
}

export function saveActiveAgentId(id: string) {
  if (typeof window === "undefined") return
  localStorage.setItem(ACTIVE_KEY, id)
  window.dispatchEvent(new CustomEvent(CHANGE_EVENT))
}

export function composeSystemPrompt(
  base: string,
  agent: Agent | undefined,
): string {
  if (!agent) return base
  return `${base}\n\nActive persona: ${agent.name} — ${agent.role}\n${agent.prompt}`
}

export function newAgentId(): string {
  return `agent-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 6)}`
}