/** Loader configuration and deployment bounds. @module dsh-evolver/config */

import { join } from 'node:path'
import { resolveDshHome } from '@deepseek-ai/dsh-home-paths'
import z from '@deepseek-ai/schemastery'

/** User-configurable plugin settings. */
export interface Config {
  readonly dataDir?: string
  readonly maxEvidenceChars?: number
  readonly maxPromotedStrategies?: number
  readonly evaluationWindowSize?: number
  readonly minimumEvaluationSamples?: number
  readonly regressionThreshold?: number
  readonly reproposalAfterOccurrences?: number
  readonly generationReservationTimeoutMs?: number
}

/** Fully resolved settings used by runtime modules. */
export interface ResolvedConfig {
  readonly dataDir: string
  readonly maxEvidenceChars: number
  readonly maxPromotedStrategies: number
  readonly evaluationWindowSize: number
  readonly minimumEvaluationSamples: number
  readonly regressionThreshold: number
  readonly reproposalAfterOccurrences: number
  readonly generationReservationTimeoutMs: number
}

/** Loader-visible schema. */
export const Config = z.object({
  dataDir: z.string(),
  maxEvidenceChars: z.natural().default(512),
  maxPromotedStrategies: z.natural().default(8),
  evaluationWindowSize: z.natural().default(20),
  minimumEvaluationSamples: z.natural().default(5),
  regressionThreshold: z.number().default(0.15),
  reproposalAfterOccurrences: z.natural().default(5),
  generationReservationTimeoutMs: z.natural().default(300_000),
}) as unknown as z<Config>

function positiveSafe(value: number, field: string): number {
  if (!Number.isSafeInteger(value) || value < 1) {
    throw new Error(`dsh-evolver: ${field} must be a positive safe integer`)
  }
  return value
}

/** Resolve defaults and reject unsafe storage or prompt bounds. */
export function resolveConfig(config: Config): ResolvedConfig {
  const maxEvidenceChars = positiveSafe(config.maxEvidenceChars ?? 512, 'maxEvidenceChars')
  if (maxEvidenceChars > 4_096) {
    throw new Error('dsh-evolver: maxEvidenceChars must not exceed 4096')
  }
  const maxPromotedStrategies = positiveSafe(
    config.maxPromotedStrategies ?? 8,
    'maxPromotedStrategies',
  )
  if (maxPromotedStrategies > 32) {
    throw new Error('dsh-evolver: maxPromotedStrategies must not exceed 32')
  }
  const evaluationWindowSize = positiveSafe(
    config.evaluationWindowSize ?? 20,
    'evaluationWindowSize',
  )
  if (evaluationWindowSize > 200) {
    throw new Error('dsh-evolver: evaluationWindowSize must not exceed 200')
  }
  const minimumEvaluationSamples = positiveSafe(
    config.minimumEvaluationSamples ?? 5,
    'minimumEvaluationSamples',
  )
  if (minimumEvaluationSamples > evaluationWindowSize) {
    throw new Error('dsh-evolver: minimumEvaluationSamples must not exceed evaluationWindowSize')
  }
  const regressionThreshold = config.regressionThreshold ?? 0.15
  if (
    !Number.isFinite(regressionThreshold) ||
    regressionThreshold <= 0 ||
    regressionThreshold > 1
  ) {
    throw new Error('dsh-evolver: regressionThreshold must be greater than 0 and at most 1')
  }
  const reproposalAfterOccurrences = positiveSafe(
    config.reproposalAfterOccurrences ?? 5,
    'reproposalAfterOccurrences',
  )
  if (reproposalAfterOccurrences > 1_000) {
    throw new Error('dsh-evolver: reproposalAfterOccurrences must not exceed 1000')
  }
  const generationReservationTimeoutMs = positiveSafe(
    config.generationReservationTimeoutMs ?? 300_000,
    'generationReservationTimeoutMs',
  )
  if (generationReservationTimeoutMs > 86_400_000) {
    throw new Error('dsh-evolver: generationReservationTimeoutMs must not exceed 86400000')
  }
  const dataDir = config.dataDir ?? join(resolveDshHome(), 'evolver')
  if (dataDir.trim().length === 0) throw new Error('dsh-evolver: dataDir must be non-blank')
  return {
    dataDir,
    maxEvidenceChars,
    maxPromotedStrategies,
    evaluationWindowSize,
    minimumEvaluationSamples,
    regressionThreshold,
    reproposalAfterOccurrences,
    generationReservationTimeoutMs,
  }
}