// SPDX-FileCopyrightText: © 2026 LEDGER SAS
// SPDX-License-Identifier: Apache-2.0

import type { TezosCoinConfig } from '../config'
import type {
  APIAccount,
  APIBlock,
  APIDelegationType,
  APIOperation,
  APIOriginationType,
  APIRevealType,
  APIStakingType,
  APITokenTransfer,
  APITransactionType,
  APIUnstakeRequest,
  AccountsGetOperationsOptions,
  TokenTransfersGetOptions,
  APITokenBalance,
} from './types'
import URL from 'url'
import network from '@ledgerhq/live-network'
import { log } from '@ledgerhq/logs'

/** TzKT hard-caps `limit` at 10 000; we use a safer page size to stay well under that. */
const BLOCK_PAGE_SIZE = 1000

/** Maximum number of IDs per `id.in` request to keep URLs under the Cloudflare proxy limit (~16 KB). */
const ID_IN_CHUNK_SIZE = 100

/**
 * Coalesces concurrent `getAccountByAddress` calls for the same explorer+address into a
 * single request. During a sync both `getBalance` and the readiness hook hit this endpoint
 * in the same tick; the in-flight promise is dropped on settle, so there is no staleness.
 */
const accountByAddressInflight = new Map<string, Promise<APIAccount>>()

const clearUndefined = (obj: Record<string, unknown>) => {
  const newObj = { ...obj }
  Object.entries(newObj).forEach(([key, value]) => value === undefined && delete newObj[key])

  return newObj
}

/** Splits an array into chunks of at most `size` elements. */
function chunk<T>(arr: T[], size: number): T[][] {
  const result: T[][] = []
  for (let i = 0; i < arr.length; i += size) {
    result.push(arr.slice(i, i + size))
  }
  return result
}

/**
 * Builds the TzKT explorer client bound to the given coin config (ADR-019). The caller resolves the
 * config from its {@link Context} and passes it in, rather than the client reading a module-level
 * singleton.
 */
export function createTzktApi(config: TezosCoinConfig) {
  const explorerUrl = config.explorer.url

  /**
   * Internal helper shared by `getOperationsTransactions` and `getOperationsOrigination`.
   * Both endpoints accept the same query shape; only the URL path differs.
   */
  async function getOperationsByType(
    type: 'transactions' | 'originations',
    level: number,
    cursor?: number,
    apiQueryParams: Record<string, unknown> = {}
  ): Promise<(APITransactionType & { block: string; hash: string })[]> {
    // "sort.asc": "id" guarantees forward progress for cursor-based paging (offset.cr).
    // Without an explicit sort the API default may be descending, which would cause the
    // cursor to go backwards and produce duplicates or an infinite loop.
    const params: Record<string, unknown> = {
      'level.gte': level,
      limit: BLOCK_PAGE_SIZE,
      'sort.asc': 'id',
      ...clearUndefined(apiQueryParams),
    }
    if (cursor !== undefined) params['offset.cr'] = cursor
    const { data } = await network<(APITransactionType & { block: string; hash: string })[]>({
      url: `${explorerUrl}/v1/operations/${type}`,
      params,
    })
    return data
  }

  const api = {
    async getBlockCount(): Promise<number> {
      const { data } = await network<number>({
        url: `${explorerUrl}/v1/blocks/count`,
      })
      return data
    },
    async getLastBlock(): Promise<{ hash: string; level: number; date: Date }> {
      const { data } = await network<APIBlock[]>({
        url: `${explorerUrl}/v1/blocks`,
        params: {
          'sort.desc': 'level',
        },
      })

      return {
        hash: data[0].hash,
        level: data[0].level,
        date: new Date(data[0].timestamp),
      }
    },
    async getAccountByAddress(address: string): Promise<APIAccount> {
      const key = `${explorerUrl}|${address}`
      const existing = accountByAddressInflight.get(key)
      if (existing) return existing
      const request = network<APIAccount>({
        url: `${explorerUrl}/v1/accounts/${address}`,
      })
        .then(({ data }) => data)
        .finally(() => accountByAddressInflight.delete(key))
      accountByAddressInflight.set(key, request)
      return request
    },

    /**
     * Returns the total `actualAmount` (mutez) summed over the account's `finalizable`
     * unstake requests — the portion of `unstakedBalance` whose unlock cycle has been
     * reached and that can be reclaimed via `finalize_unstake`. The complementary
     * `unstakedBalance - finalizable` portion is still in the deactivation delay window.
     *
     * TzKT's account endpoint does not expose this split, so we sum from
     * `/v1/staking/unstake_requests`. https://api.tzkt.io/#operation/Staking_GetUnstakeRequests
     *
     * `limit=1000` covers any realistic number of concurrent finalizable requests for
     * a single staker — we do not paginate.
     */
    async getUnstakeRequestsFinalizable(address: string): Promise<bigint> {
      const { data } = await network<number[]>({
        url: `${explorerUrl}/v1/staking/unstake_requests`,
        params: {
          'staker.eq': address,
          status: 'finalizable',
          'select.values': 'actualAmount',
          limit: 1000,
        },
      })
      return data.reduce<bigint>((sum, n) => sum + BigInt(n), 0n)
    },

    /**
     * Pending + finalizable unstake requests, by id ascending. Uses `status.ne=finalized` because
     * TzKT ignores `status.in=pending,finalizable` on this endpoint and returns finalized requests.
     * https://api.tzkt.io/#operation/Staking_GetUnstakeRequests
     */
    async getUnstakeRequests(address: string): Promise<APIUnstakeRequest[]> {
      const { data } = await network<APIUnstakeRequest[]>({
        url: `${explorerUrl}/v1/staking/unstake_requests`,
        params: {
          'staker.eq': address,
          'status.ne': 'finalized',
          'sort.asc': 'id',
          limit: 1000,
        },
      })
      return data
    },
    // https://api.tzkt.io/#operation/Accounts_GetOperations
    async getAccountOperations(
      address: string,
      query: AccountsGetOperationsOptions
    ): Promise<APIOperation[]> {
      // Remove undefined from query
      Object.entries(query).forEach(
        ([key, value]) => value === undefined && delete query[key as keyof typeof query]
      )
      const { data } = await network<APIOperation[]>({
        url: URL.format({
          pathname: `${explorerUrl}/v1/accounts/${address}/operations`,
          query,
        }),
      })
      return data
    },

    // https://api.tzkt.io/#operation/Blocks_GetByLevel
    async getBlockByLevel(level: number): Promise<APIBlock> {
      const { data } = await network<APIBlock>({
        url: `${explorerUrl}/v1/blocks/${level}`,
      })
      return data
    },

    /**
     * Resolves block hashes for the given levels in a single request.
     * Uses `/v1/blocks?level.in=...&select.values=level,hash`, which TzKT honours
     * (unlike `/v1/blocks/{level}?select=...`, where `select` is ignored). Used
     * for cheap backfill of `block.hash` on operations whose level is known but
     * whose response omits the block field (e.g. `/accounts/{addr}/operations`
     * for staking ops). Levels that don't resolve are absent from the result map.
     */
    async getBlockHashesByLevels(levels: readonly number[]): Promise<Map<number, string>> {
      if (levels.length === 0) return new Map()
      const { data } = await network<[number, string][]>({
        url: `${explorerUrl}/v1/blocks`,
        params: {
          'level.in': levels.join(','),
          'select.values': 'level,hash',
          limit: levels.length,
        },
      })
      return new Map(data)
    },

    /**
     * Fetches a single page of `transaction` operations at the given block level.
     * Internal — used by `fetchBlockTransactions` which handles pagination.
     * https://api.tzkt.io/#operation/Operations_GetTransactions
     */
    async getBlockTransactionsPage(level: number, cursor?: number): Promise<APITransactionType[]> {
      // "sort.asc": "id" guarantees forward progress for cursor-based paging (offset.cr).
      // Without an explicit sort the API default may be descending, which would cause the
      // cursor to go backwards and produce duplicates or an infinite loop.
      const params: Record<string, unknown> = { level, limit: BLOCK_PAGE_SIZE, 'sort.asc': 'id' }
      if (cursor !== undefined) params['offset.cr'] = cursor
      const { data } = await network<APITransactionType[]>({
        url: `${explorerUrl}/v1/operations/transactions`,
        params,
      })
      return data
    },

    /**
     * Fetches a list of `transaction` operations after the given level.
     * https://api.tzkt.io/#operation/Operations_GetTransactions
     */
    async getOperationsTransactions(
      level: number,
      cursor?: number,
      apiQueryParams: Record<string, unknown> = {}
    ): Promise<(APITransactionType & { block: string; hash: string })[]> {
      return getOperationsByType('transactions', level, cursor, apiQueryParams)
    },

    /**
     * Fetches a list of `originations` operations after the given level.
     * https://api.tzkt.io/#operation/Operations_GetOriginations
     */
    async getOperationsOrigination(
      level: number,
      cursor?: number,
      apiQueryParams: Record<string, unknown> = {}
    ): Promise<(APITransactionType & { block: string; hash: string })[]> {
      return getOperationsByType('originations', level, cursor, apiQueryParams)
    },

    /**
     * Fetches a single page of FA token transfers at the given block level.
     * Internal — used by `fetchBlockTokenTransfers` which handles pagination.
     * https://api.tzkt.io/#operation/Tokens_GetTokenTransfers
     */
    async getBlockTokenTransfersPage(level: number, cursor?: number): Promise<APITokenTransfer[]> {
      // Same rationale as getBlockTransactionsPage: explicit ascending sort keeps the
      // offset.cr cursor advancing forward regardless of the API's default ordering.
      const params: Record<string, unknown> = {
        level,
        limit: BLOCK_PAGE_SIZE,
        'sort.asc': 'id',
        'token.standard': 'fa2',
      }
      if (cursor !== undefined) params['offset.cr'] = cursor
      const { data } = await network<APITokenTransfer[]>({
        url: `${explorerUrl}/v1/tokens/transfers`,
        params,
      })
      return data
    },

    /**
     * Fetches the latest FA token transfers since the given level.
     * https://api.tzkt.io/#operation/Tokens_GetTokenTransfers
     */
    async getTokenTransfers(
      apiQueryParams: Record<string, unknown> = {}
    ): Promise<APITokenTransfer[]> {
      const params = {
        ...clearUndefined(apiQueryParams),
      }
      const { data } = await network<APITokenTransfer[]>({
        url: `${explorerUrl}/v1/tokens/transfers`,
        params,
      })
      return data
    },

    /**
     * Fetches a single page of `origination` operations at the given block level.
     * Internal — used by `fetchBlockOriginations` which handles pagination.
     * https://api.tzkt.io/#operation/Operations_GetOriginations
     */
    async getBlockOriginationsPage(level: number, cursor?: number): Promise<APIOriginationType[]> {
      const params: Record<string, unknown> = { level, limit: BLOCK_PAGE_SIZE, 'sort.asc': 'id' }
      if (cursor !== undefined) params['offset.cr'] = cursor
      const { data } = await network<APIOriginationType[]>({
        url: `${explorerUrl}/v1/operations/originations`,
        params,
      })
      return data
    },

    /**
     * Fetches a single page of `reveal` operations at the given block level.
     * Internal — used by `fetchBlockReveals` which handles pagination.
     * https://api.tzkt.io/#operation/Operations_GetReveals
     */
    async getBlockRevealsPage(level: number, cursor?: number): Promise<APIRevealType[]> {
      const params: Record<string, unknown> = { level, limit: BLOCK_PAGE_SIZE, 'sort.asc': 'id' }
      if (cursor !== undefined) params['offset.cr'] = cursor
      const { data } = await network<APIRevealType[]>({
        url: `${explorerUrl}/v1/operations/reveals`,
        params,
      })
      return data
    },

    /**
     * Fetches a single page of `delegation` operations at the given block level.
     * Internal — used by `fetchBlockDelegations` which handles pagination.
     * https://api.tzkt.io/#operation/Operations_GetDelegations
     */
    async getBlockDelegationsPage(level: number, cursor?: number): Promise<APIDelegationType[]> {
      const params: Record<string, unknown> = { level, limit: BLOCK_PAGE_SIZE, 'sort.asc': 'id' }
      if (cursor !== undefined) params['offset.cr'] = cursor
      const { data } = await network<APIDelegationType[]>({
        url: `${explorerUrl}/v1/operations/delegations`,
        params,
      })
      return data
    },

    /**
     * Fetches a single page of `staking` operations at the given block level.
     * Internal — used by `fetchBlockStaking` which handles pagination.
     * https://api.tzkt.io/#operation/Operations_GetStaking
     */
    async getBlockStakingPage(level: number, cursor?: number): Promise<APIStakingType[]> {
      const params: Record<string, unknown> = { level, limit: BLOCK_PAGE_SIZE, 'sort.asc': 'id' }
      if (cursor !== undefined) params['offset.cr'] = cursor
      const { data } = await network<APIStakingType[]>({
        url: `${explorerUrl}/v1/operations/staking`,
        params,
      })
      return data
    },

    /**
     * Fetches FA2 token transfers for a given account.
     * Translates `query.sort` to TzKT's `sort.asc=id` / `sort.desc=id`.
     * The lower-level `getTokenTransfers` helper is a generic pass-through and does not pin the sort.
     * https://api.tzkt.io/#operation/Tokens_GetTokenTransfers
     */
    async getAccountTokenTransfers(
      address: string,
      query: TokenTransfersGetOptions
    ): Promise<(APITokenTransfer & { hash: string; block: string })[]> {
      const sortKey = query.sort === 'Descending' ? 'sort.desc' : 'sort.asc'
      const params: Record<string, unknown> = {
        'anyof.from.to': address,
        'token.standard': 'fa2',
        [sortKey]: 'id',
        limit: query.limit,
        'level.ge': query['level.ge'],
        'level.lt': query['level.lt'],
        'level.gt': query['level.gt'],
        'id.lt': query['id.lt'],
        'id.gt': query['id.gt'],
      }

      const data = await api.getTokenTransfers(clearUndefined(params))

      const transactionIds = data
        .map((t) => t.transactionId)
        .filter((id): id is number => typeof id === 'number')

      const originationIds = data
        .map((t) => t.originationId)
        .filter((id): id is number => typeof id === 'number')

      if (transactionIds.length === 0 && originationIds.length === 0) {
        return []
      }

      const transactions = transactionIds.length
        ? (
            await Promise.all(
              chunk(transactionIds, ID_IN_CHUNK_SIZE).map((ids) =>
                api.getOperationsTransactions(query['level.ge'] || 0, undefined, {
                  'id.in': ids.join(','),
                })
              )
            )
          ).flat()
        : []

      const originations = originationIds.length
        ? (
            await Promise.all(
              chunk(originationIds, ID_IN_CHUNK_SIZE).map((ids) =>
                api.getOperationsOrigination(query['level.ge'] || 0, undefined, {
                  'id.in': ids.join(','),
                })
              )
            )
          ).flat()
        : []

      // Build id -> operation maps once so per-transfer lookups are O(1) instead of O(n).
      // Keys are widened to `number | undefined` so lookups with a missing id naturally
      // return `undefined` (no entry is ever stored under the `undefined` key).
      const transactionsById = new Map<number | undefined, (typeof transactions)[number]>(
        transactions.map((t) => [t.id, t])
      )
      const originationsById = new Map<number | undefined, (typeof originations)[number]>(
        originations.map((o) => [o.id, o])
      )

      return data.map((token) => {
        const transaction = transactionsById.get(token.transactionId)
        const origination = originationsById.get(token.originationId)

        return {
          ...token,
          hash: transaction?.hash ?? origination?.hash ?? '',
          block: transaction?.block ?? origination?.block ?? '',
        }
      })
    },

    /**
     * Fetches FA2 token balances for a given account.
     * When `tokenFilter` is omitted, all FA2 token balances are returned.
     * Pass `tokenFilter` to query a specific FA2 contract + token id (e.g. send-max for FA2).
     * https://api.tzkt.io/#operation/Tokens_GetTokenBalances
     */
    async getTokensBalances(
      address: string,
      tokenFilter?: { contractAddress: string; tokenId: number }
    ): Promise<APITokenBalance[]> {
      const params: Record<string, unknown> = {
        account: address,
        'token.standard': 'fa2',
      }
      if (tokenFilter) {
        params['token.contract'] = tokenFilter.contractAddress
        params['token.tokenId'] = String(tokenFilter.tokenId)
      }
      const { data } = await network<APITokenBalance[]>({
        url: `${explorerUrl}/v1/tokens/balances`,
        params,
      })
      return data
    },
  }

  return api
}

/** The TzKT explorer client bound to a coin config, as returned by {@link createTzktApi}. */
export type TzktApi = ReturnType<typeof createTzktApi>

// TODO this has same purpose as api/listOperations
export const fetchAllTransactions = async (
  config: TezosCoinConfig,
  address: string,
  lastId?: number
): Promise<APIOperation[]> => {
  const api = createTzktApi(config)
  let ops: APIOperation[] = []
  let maxIteration = config.explorer.maxTxQuery
  do {
    const newOps = await api.getAccountOperations(address, {
      lastId,
      sort: 'Ascending',
      'level.ge': 0,
    })
    if (newOps.length === 0) return ops
    ops = ops.concat(newOps)
    const last = ops[ops.length - 1]
    if (!last) return ops
    lastId = last.id
    if (!lastId) {
      log('tezos', 'id missing!')
      return ops
    }
  } while (--maxIteration)
  return ops
}

/**
 * Generic paginated fetcher for block-level operations.
 *
 * TzKT hard-caps a single request at 10 000 items. This function issues multiple
 * requests when needed and is therefore safe for dense blocks.
 * A safety cap (`maxTxQuery`) prevents infinite loops on pathological responses.
 */
async function fetchBlockPaginated<T extends { id: number }>(
  config: TezosCoinConfig,
  pageFn: (level: number, cursor?: number) => Promise<T[]>,
  level: number,
  label: string
): Promise<T[]> {
  const items: T[] = []
  let cursor: number | undefined
  let maxIteration = config.explorer.maxTxQuery
  do {
    const page = await pageFn(level, cursor)
    if (page.length === 0) break
    items.push(...page)
    if (page.length < BLOCK_PAGE_SIZE) break
    cursor = page.at(-1)!.id
  } while (--maxIteration > 0)
  if (maxIteration === 0) {
    log('tezos', `${label}: maxTxQuery limit reached at level ${level}, result may be incomplete`)
  }
  return items
}

export const fetchBlockTransactions = (config: TezosCoinConfig, level: number) =>
  fetchBlockPaginated(
    config,
    createTzktApi(config).getBlockTransactionsPage,
    level,
    'fetchBlockTransactions'
  )

export const fetchBlockTokenTransfers = (config: TezosCoinConfig, level: number) =>
  fetchBlockPaginated(
    config,
    createTzktApi(config).getBlockTokenTransfersPage,
    level,
    'fetchBlockTokenTransfers'
  )

export const fetchBlockDelegations = (config: TezosCoinConfig, level: number) =>
  fetchBlockPaginated(
    config,
    createTzktApi(config).getBlockDelegationsPage,
    level,
    'fetchBlockDelegations'
  )

export const fetchBlockStaking = (config: TezosCoinConfig, level: number) =>
  fetchBlockPaginated(config, createTzktApi(config).getBlockStakingPage, level, 'fetchBlockStaking')

export const fetchBlockOriginations = (config: TezosCoinConfig, level: number) =>
  fetchBlockPaginated(
    config,
    createTzktApi(config).getBlockOriginationsPage,
    level,
    'fetchBlockOriginations'
  )

export const fetchBlockReveals = (config: TezosCoinConfig, level: number) =>
  fetchBlockPaginated(config, createTzktApi(config).getBlockRevealsPage, level, 'fetchBlockReveals')