// Settlement Trigger: connects verification approval to point reward + escrow + ledger
// Patent claims 1, 5: verification → settlement automatic binding

import { supabase } from './supabase'
import { getNatureSubject, getDefaultNatureSubject } from './natureSubjects'
import type { Campaign } from './database.types'
import { appendLedgerEntry } from './ledger'

/**
 * 캠페인에 등록된 자연 주체로 크레딧을 상쇄(retire)한다.
 * receiver는 반드시 `nature:*` ID — 자연이 원장 거래 당사자로 기록됨.
 * 특허 청구항 1·4: 자연 권리 기록 모듈.
 */
export async function retireCreditToNature(params: {
  transactionId: string
  campaign: Pick<Campaign, 'id' | 'nature_beneficiary_id' | 'nature_beneficiary_name'>
  senderId: string
  senderName: string
  amountTon: number
  idempotencyKey: string
  description?: string
  scope3CertId?: string
}): Promise<void> {
  const nature =
    getNatureSubject(params.campaign.nature_beneficiary_id) ?? getDefaultNatureSubject()
  await appendLedgerEntry({
    transactionId: params.transactionId,
    campaignId: params.campaign.id,
    senderId: params.senderId,
    senderName: params.senderName,
    receiverId: nature.id,
    receiverName: params.campaign.nature_beneficiary_name ?? nature.name,
    category: 'CREDIT_RETIRE',
    asset: 'TON',
    amount: params.amountTon,
    idempotencyKey: params.idempotencyKey,
    description:
      params.description ??
      `${params.senderName} → ${nature.name}로 ${params.amountTon.toFixed(4)} tCO₂e 회복`,
    referenceData: {
      natureBeneficiary: nature.id,
      scope3CertId: params.scope3CertId,
    },
  })
}

// --- Reward calculation ---

export function calculateRewardPoints(
  co2Grams: number,
  missionRewardPoints: number | null,
  campaign: { budget_krw: number; reward_pool_rate: number; target_co2_kg: number },
): { points: number; krw: number } {
  // Fixed points per mission if defined
  if (missionRewardPoints != null && missionRewardPoints > 0) {
    return { points: missionRewardPoints, krw: missionRewardPoints }
  }

  // Dynamic: proportional to CO2 contribution vs campaign target
  const rewardPool = campaign.budget_krw * campaign.reward_pool_rate
  const co2Kg = co2Grams / 1000
  const targetKg = campaign.target_co2_kg || 1 // avoid division by zero
  const points = Math.max(1, Math.floor((co2Kg / targetKg) * rewardPool))
  return { points, krw: points }
}

// --- Settlement pipeline (atomic via RPC) ---

export async function processApprovedSubmission(params: {
  submissionId: string
  userId: string
  campaignId: string
  co2Grams: number
  rewardPoints: number
  rewardKrw: number
}): Promise<void> {
  const { error } = await supabase.rpc('process_approved_submission', {
    p_submission_id: params.submissionId,
    p_user_id: params.userId,
    p_campaign_id: params.campaignId,
    p_co2_grams: params.co2Grams,
    p_reward_points: params.rewardPoints,
    p_reward_krw: params.rewardKrw,
  })
  if (error) throw error
}

// --- Query helpers ---

export async function getUserPointBalance(userId: string, campaignId: string): Promise<{
  totalEarned: number
  totalUsed: number
  available: number
} | null> {
  const { data, error } = await supabase
    .from('point_balances')
    .select('*')
    .eq('user_id', userId)
    .eq('campaign_id', campaignId)
    .maybeSingle()
  if (error) throw error
  if (!data) return null
  return {
    totalEarned: data.total_earned,
    totalUsed: data.total_used,
    available: data.available,
  }
}

export async function getPointTransactions(userId: string, campaignId?: string): Promise<Array<{
  id: string
  type: string
  amount: number
  description: string | null
  createdAt: string
}>> {
  let query = supabase
    .from('point_transactions')
    .select('*')
    .eq('user_id', userId)
    .order('created_at', { ascending: false })

  if (campaignId) query = query.eq('campaign_id', campaignId)

  const { data, error } = await query
  if (error) throw error
  return (data ?? []).map((row) => ({
    id: row.id,
    type: row.type,
    amount: row.amount,
    description: row.description,
    createdAt: row.created_at,
  }))
}



// --- Verification & Credit Issuance automatic binding ---

/**
 * VCS/Gold Standard 등 외부 레지스트리 프로젝트 매핑이 최종 VVB approved 승인되었을 때,
 * 해당 캠페인에 대한 감축 실적을 바탕으로 공식 탄소 크레딧(TON)을 발행 및 정산 분배합니다.
 * 특허 청구항 1, 5: verification → settlement automatic binding
 */
export async function triggerCampaignSettlementOnApproval(mappingId: string): Promise<void> {
  // 1. 매핑 정보 및 연결된 캠페인 조회
  const { data: mapping, error: mapErr } = await supabase
    .from('external_project_mappings')
    .select('*, campaigns:internal_id(id, title, nature_beneficiary_id, nature_beneficiary_name, target_co2_kg)')
    .eq('id', mappingId)
    .single()

  if (mapErr || !mapping) {
    throw new Error(`[triggerCampaignSettlementOnApproval] 매핑 정보를 찾을 수 없습니다. (ID: ${mappingId})`)
  }

  // 이중 정산 발행 방지 가드
  if (mapping.verification_level === 'approved') {
    throw new Error(`[triggerCampaignSettlementOnApproval] 이미 승인 및 정산 완료된 매핑입니다. (ID: ${mappingId})`)
  }

  const camp = mapping.campaigns as any
  if (!camp) {
    throw new Error(`[triggerCampaignSettlementOnApproval] 매핑에 연결된 캠페인 정보가 없습니다. (ID: ${mappingId})`)
  }

  // 2. 해당 캠페인의 총 승인 감축량(CO2 grams) 계산
  const { data: activities, error: actErr } = await supabase
    .from('activities')
    .select('co2_grams')
    .eq('campaign_id', camp.id)
    .eq('status', 'approved')

  if (actErr) throw actErr

  let totalCo2Grams = 0
  if (activities && activities.length > 0) {
    totalCo2Grams = activities.reduce((sum, act) => sum + (act.co2_grams || 0), 0)
  }

  // 감축 실적이 0일 경우, 캠페인 목표치 target_co2_kg를 폴백으로 사용
  let amountTon = 0
  if (totalCo2Grams > 0) {
    amountTon = totalCo2Grams / 1000000 // 1,000,000 g = 1 tCO2e = 1 TON
  } else {
    const targetKg = Number(camp.target_co2_kg || 0)
    amountTon = targetKg / 1000 // 1,000 kg = 1 TON
  }

  // 발행할 톤수가 0이하이면 발행 불가
  if (amountTon <= 0) {
    amountTon = 1.0 // 기본 폴백 최소 1톤 보장
  }

  // 고유한 transactionId 생성 (mappingId + timestamp)
  const transactionId = `txn-issuance-${mappingId}-${Date.now()}`
  const idempotencyKey = `idem-issuance-${mappingId}`

  // 3. appendLedgerEntry를 통해 원장에 CREDIT_ISSUANCE 공식 발행 기록
  await appendLedgerEntry({
    transactionId,
    campaignId: camp.id,
    senderId: mapping.registry_code,
    senderName: mapping.registry_code,
    receiverId: camp.nature_beneficiary_id || 'nature:unspecified',
    receiverName: camp.nature_beneficiary_name || '자연 보존림',
    category: 'CREDIT_ISSUANCE',
    asset: 'TON',
    amount: amountTon,
    idempotencyKey,
    description: `공식 검증 통과에 따른 탄소 크레딧 발행: ${mapping.registry_code} → ${camp.nature_beneficiary_name || '자연'} (${amountTon.toFixed(2)} TON)`,
  })

  // 4. 캠페인 동적 분배 비율 조회
  const { data: rules } = await supabase
    .from('distribution_rules')
    .select('*')
    .eq('campaign_id', camp.id)
    .maybeSingle()

  const reserveRate = Number(rules?.reserve_rate ?? 0.70)
  const donationRate = Number(rules?.donation_rate ?? 0.20)
  const platformRate = Number(rules?.platform_rate ?? 0.10)

  // 5. 산출된 각 지분 비율에 맞춰 크레딧 지분 분배 원장 3회 순차 기록
  // 자바스크립트 부동소수점 오차 보정을 위해 소수점 4째 자리까지 반올림 정규화 처리
  const reserveAmount = Math.round(amountTon * reserveRate * 10000) / 10000
  if (reserveAmount > 0) {
    await appendLedgerEntry({
      transactionId,
      campaignId: camp.id,
      senderId: camp.nature_beneficiary_id || 'nature:unspecified',
      senderName: camp.nature_beneficiary_name || '자연',
      receiverId: camp.nature_beneficiary_id || 'nature:unspecified',
      receiverName: camp.nature_beneficiary_name || '자연',
      category: 'CREDIT_RETIRE', // 자연에 영구 귀속 및 상쇄
      asset: 'TON',
      amount: reserveAmount,
      idempotencyKey: `${idempotencyKey}-reserve`,
      description: `동적 지분 분배 [Reserve ${reserveRate * 100}%]: 자연 환원 크레딧 영구 상쇄 (${reserveAmount.toFixed(4)} TON)`,
    })
  }

  const donationAmount = Math.round(amountTon * donationRate * 10000) / 10000
  if (donationAmount > 0) {
    await appendLedgerEntry({
      transactionId,
      campaignId: camp.id,
      senderId: camp.nature_beneficiary_id || 'nature:unspecified',
      senderName: camp.nature_beneficiary_name || '자연',
      receiverId: 'sme:allocated',
      receiverName: 'SME ESG 지원 수혜 풀',
      category: 'CREDIT_DONATION',
      asset: 'TON',
      amount: donationAmount,
      idempotencyKey: `${idempotencyKey}-donation`,
      description: `동적 지분 분배 [SME ${donationRate * 100}%]: 수혜 중소기업 ESG Scope 3 할당 풀 이관 (${donationAmount.toFixed(4)} TON)`,
    })
  }

  const platformAmount = Math.round(amountTon * platformRate * 10000) / 10000
  if (platformAmount > 0) {
    await appendLedgerEntry({
      transactionId,
      campaignId: camp.id,
      senderId: camp.nature_beneficiary_id || 'nature:unspecified',
      senderName: camp.nature_beneficiary_name || '자연',
      receiverId: 'platform:fees',
      receiverName: 'Carboany 플랫폼 수수료 원장',
      category: 'FEE_DEDUCTION',
      asset: 'TON',
      amount: platformAmount,
      idempotencyKey: `${idempotencyKey}-platform`,
      description: `동적 지분 분배 [Platform ${platformRate * 100}%]: 플랫폼 운영 수수료 징수 (${platformAmount.toFixed(4)} TON)`,
    })
  }
}