// Instance settings data layer (#79): admin-only, instance-wide configuration.
//
// The GET/PATCH return both the stored settings and a read-only "effective" view
// — what's actually in force after layering the DB over the environment — so the
// form can say "inheriting ollama-cloud/glm-5.2:cloud from the environment" and
// whether the API key is present, without the key ever crossing the wire.

import { queryOptions, useMutation, useQuery, useQueryClient } from '@tanstack/react-query'
import { z } from 'zod'
import { ApiError, api } from './api'
import { capabilitiesKey } from './agent'

export const instanceSettingsSchema = z.object({
  // '' means "inherit the PANSY_AGENT_MODEL env var".
  agentModel: z.string(),
  // null means "inherit PANSY_AGENT_ENABLED"; true/false is an explicit override.
  agentEnabled: z.boolean().nullable(),
  version: z.number(),
  updatedAt: z.string(),
})
export type InstanceSettings = z.infer<typeof instanceSettingsSchema>

export const effectiveAgentSchema = z.object({
  model: z.string(),
  enabled: z.boolean(),
  hasApiKey: z.boolean(),
  agentLive: z.boolean(),
})
export type EffectiveAgent = z.infer<typeof effectiveAgentSchema>

export const settingsResponseSchema = z.object({
  settings: instanceSettingsSchema,
  effective: effectiveAgentSchema,
})
export type SettingsResponse = z.infer<typeof settingsResponseSchema>

export const settingsKey = ['settings'] as const

export const settingsQueryOptions = queryOptions({
  queryKey: settingsKey,
  queryFn: async (): Promise<SettingsResponse> =>
    settingsResponseSchema.parse(await api.get('/settings')),
})

export function useSettings() {
  return useQuery(settingsQueryOptions)
}

export interface SettingsUpdate {
  agentModel: string
  agentEnabled: boolean | null
  version: number
}

export function useUpdateSettings() {
  const qc = useQueryClient()
  return useMutation({
    mutationFn: async (input: SettingsUpdate): Promise<SettingsResponse> =>
      settingsResponseSchema.parse(await api.patch('/settings', input)),
    onSuccess: (res) => {
      qc.setQueryData(settingsKey, res)
      // The save may have turned the assistant on or off; the editor keys its
      // chat tab off /capabilities, so make it re-read rather than trust its
      // cached answer.
      qc.invalidateQueries({ queryKey: capabilitiesKey })
    },
  })
}

/** If err is a 409 version conflict, return the fresh settings it carries so a
 *  form can rebase; otherwise null. */
export function conflictSettings(err: unknown): InstanceSettings | null {
  if (err instanceof ApiError && err.isConflict && err.body && typeof err.body === 'object') {
    const current = (err.body as { current?: unknown }).current
    const parsed = instanceSettingsSchema.safeParse(current)
    if (parsed.success) return parsed.data
  }
  return null
}