/**
 * 规则包归一化。
 *
 * `GET /api/rules/export` 返回裸 YAML（服务端 rules.Marshal），这里把解析出的
 * unknown 收敛成 shared 的 RulePack 契约：补齐缺省值、丢弃未知字段。
 * 校验口径与服务端 rules.Canonical 对齐，避免前端拿到的规则包和实际生效规则不一致。
 */

import { normalizeCountToTeam } from './channels'
import {
  asRecord,
  emptyToNull,
  firstBool,
  firstNumber,
  firstNumberOrNull,
  firstString,
  isRecord,
} from './internal'
import type {
  ChannelBasis,
  ChannelScope,
  ChannelTemplate,
  EventOverride,
  EventType,
  RecordBonusLevel,
  RecordBonusMode,
  ResultType,
  RuleChannel,
  RulePack,
  RulePackManualAdjustment,
  RulePackMeta,
  RulePackRecordBonus,
  RulePackStandings,
  RuleProfile,
  ScoringProfileRule,
  TieBreakKey,
  TieMode,
} from './types'

const TIE_BREAK_KEYS: readonly TieBreakKey[] = [
  'points',
  'gold',
  'silver',
  'bronze',
  'teamCode',
  'name',
]
const DEFAULT_TIE_BREAK: TieBreakKey[] = ['points', 'gold', 'silver', 'bronze', 'teamCode']
const TIE_MODES: readonly TieMode[] = ['skip', 'average', 'higher']
const RECORD_BONUS_MODES: readonly RecordBonusMode[] = ['max', 'sum']
const SCOPES: readonly ChannelScope[] = ['athlete', 'team']
const BASES: readonly ChannelBasis[] = ['result', 'manual', 'aggregate']
const EVENT_TYPES: readonly EventType[] = ['individual', 'team', 'match', 'individual_team']
const RESULT_TYPES: readonly ResultType[] = ['time', 'distance', 'count', 'score', 'none']

export function normalizeRulePack(raw: unknown): RulePack | null {
  if (!isRecord(raw)) return null
  if (firstString(raw.format) !== 'scoreboard-rules') return null
  if (firstNumber(0, raw.formatVersion) !== 1) return null
  return {
    format: 'scoreboard-rules',
    formatVersion: 1,
    meta: normalizeMeta(raw.meta),
    standings: normalizeStandings(raw.standings),
    profiles: normalizeProfiles(raw.profiles),
    recordBonus: normalizeRecordBonus(raw.recordBonus),
    manualAdjustment: normalizeManualAdjustment(raw.manualAdjustment),
    channelTemplates: normalizeTemplates(raw.channelTemplates),
    eventOverrides: normalizeOverrides(raw.eventOverrides),
  }
}

function oneOf<T extends string>(value: unknown, allowed: readonly T[], fallback: T): T {
  return typeof value === 'string' && (allowed as readonly string[]).includes(value)
    ? (value as T)
    : fallback
}

function optionalOneOf<T extends string>(value: unknown, allowed: readonly T[]): T | undefined {
  return typeof value === 'string' && (allowed as readonly string[]).includes(value)
    ? (value as T)
    : undefined
}

function normalizeMeta(raw: unknown): RulePackMeta {
  const rec = asRecord(raw)
  return {
    code: firstString(rec.code) ?? '',
    name: firstString(rec.name) ?? '',
    version: firstString(rec.version) ?? '',
    updatedAt: firstString(rec.updatedAt) ?? '',
    author: emptyToNull(firstString(rec.author)),
    note: emptyToNull(firstString(rec.note)),
  }
}

function normalizeStandings(raw: unknown): RulePackStandings {
  const rec = asRecord(raw)
  const tieBreakRaw = rec.tieBreak
  const tieBreak = Array.isArray(tieBreakRaw)
    ? tieBreakRaw.filter(
        (item): item is TieBreakKey =>
          typeof item === 'string' && (TIE_BREAK_KEYS as readonly string[]).includes(item),
      )
    : []
  return {
    individualToTeamWeight: firstNumber(1, rec.individualToTeamWeight),
    tieBreak: tieBreak.length > 0 ? tieBreak : [...DEFAULT_TIE_BREAK],
    medalCountsTeamEvents: firstBool(true, rec.medalCountsTeamEvents),
    showIndividualBoard: firstBool(true, rec.showIndividualBoard),
    showIndividualMedals: firstBool(true, rec.showIndividualMedals),
  }
}

function normalizeProfiles(raw: unknown): RuleProfile[] {
  if (!Array.isArray(raw)) return []
  const out: RuleProfile[] = []
  for (const item of raw) {
    const rec = asRecord(item)
    const code = firstString(rec.code)
    if (code === null || code === '') continue
    out.push({
      code,
      name: firstString(rec.name) ?? code,
      awardRanks: firstNumber(0, rec.awardRanks),
      lastPlaceZero: firstBool(false, rec.lastPlaceZero),
      tieMode: oneOf(rec.tieMode, TIE_MODES, 'skip'),
      recordBonusMode: optionalOneOf(rec.recordBonusMode, RECORD_BONUS_MODES),
      rules: normalizeScoringRules(rec.rules),
    })
  }
  return out
}

function normalizeScoringRules(raw: unknown): ScoringProfileRule[] {
  if (!Array.isArray(raw)) return []
  const out: ScoringProfileRule[] = []
  for (const item of raw) {
    const rec = asRecord(item)
    const rank = firstNumberOrNull(rec.rank)
    const points = firstNumberOrNull(rec.points)
    if (rank === null || points === null) continue
    out.push({ rank, points })
  }
  return out
}

function normalizeRecordBonus(raw: unknown): RulePackRecordBonus {
  const rec = asRecord(raw)
  return {
    enabled: firstBool(false, rec.enabled),
    mode: oneOf(rec.mode, RECORD_BONUS_MODES, 'max'),
    levels: normalizeLevels(rec.levels),
  }
}

function normalizeLevels(raw: unknown): RecordBonusLevel[] {
  if (!Array.isArray(raw)) return []
  const out: RecordBonusLevel[] = []
  for (const item of raw) {
    const rec = asRecord(item)
    const code = firstString(rec.code)
    if (code === null || code === '') continue
    out.push({ code, name: firstString(rec.name) ?? code, points: firstNumber(0, rec.points) })
  }
  return out
}

function normalizeManualAdjustment(raw: unknown): RulePackManualAdjustment {
  const rec = asRecord(raw)
  return {
    enabled: firstBool(false, rec.enabled),
    reasonRequired: firstBool(true, rec.reasonRequired),
  }
}

function normalizeTemplates(raw: unknown): ChannelTemplate[] {
  if (!Array.isArray(raw)) return []
  return raw.map((item) => {
    const rec = asRecord(item)
    const match = asRecord(rec.match)
    return {
      match: {
        eventType: optionalOneOf(match.eventType, EVENT_TYPES),
        resultType: optionalOneOf(match.resultType, RESULT_TYPES),
        sportCode: firstString(match.sportCode) ?? undefined,
      },
      channels: normalizeChannels(rec.channels),
    }
  })
}

function normalizeOverrides(raw: unknown): EventOverride[] {
  if (!Array.isArray(raw)) return []
  const out: EventOverride[] = []
  for (const item of raw) {
    const rec = asRecord(item)
    const eventCode = firstString(rec.eventCode)
    if (eventCode === null || eventCode === '') continue
    const override: EventOverride = { eventCode }
    const name = firstString(rec.name)
    if (name !== null) override.name = name
    if (typeof rec.scored === 'boolean') override.scored = rec.scored
    const multiplier = firstNumberOrNull(rec.multiplier)
    if (multiplier !== null) override.multiplier = multiplier
    // 三态：缺省表示不动该小项已有的奖牌开关，只有显式写了才落到覆盖对象上。
    if (typeof rec.awardMedals === 'boolean') override.awardMedals = rec.awardMedals
    if (Array.isArray(rec.channels)) override.channels = normalizeChannels(rec.channels)
    out.push(override)
  }
  return out
}

function normalizeChannels(raw: unknown): RuleChannel[] {
  if (!Array.isArray(raw)) return []
  const out: RuleChannel[] = []
  for (const item of raw) {
    const rec = asRecord(item)
    const profile = firstString(rec.profile)
    if (profile === null || profile === '') continue
    const channel: RuleChannel = {
      scope: oneOf(rec.scope, SCOPES, 'athlete'),
      basis: oneOf(rec.basis, BASES, 'result'),
      profile,
      // 旧规则包不写这个字段，缺省按「计入单位总分」处理。
      countToTeam: normalizeCountToTeam(rec.countToTeam),
    }
    // 两个奖牌开关同样是「缺省即开」；只有规则包显式写了才落到对象上，
    // 保留「未配置」与「显式开启」的区别，导出页才能如实显示规则包原文口径。
    if (typeof rec.countToMedals === 'boolean') channel.countToMedals = rec.countToMedals
    if (typeof rec.countToTeamMedals === 'boolean') channel.countToTeamMedals = rec.countToTeamMedals
    out.push(channel)
  }
  return out
}