import Foundation
import RastrilloApple

@MainActor extension SheetModel {
  @discardableResult func write(_ writes: [CellWrite], retrying: Bool = false) async -> Bool {
    guard failedWrites.isEmpty || retrying else {
      error = "Retry or discard the pending edits before making another change."
      return false
    }
    guard mayWrite && !busy else { return false }
    guard writes.allSatisfy({ $0.raw.utf8.count <= 8192 }) else {
      error = "A cell exceeds the input size limit. Nothing was changed."
      return false
    }
    if writes.isEmpty { return true }
    busy = true
    defer { busy = false }
    var offset = 0
    do {
      while offset < writes.count {
        let batch = try await wire.encode(writes, startingAt: offset)
        let count = batch.count
        let data = batch.data
        let (bytes, status) = try await client.response(
          grid + "/cells/batch", method: "POST", body: data, maxBytes: 64 << 20)
        guard (200..<300).contains(status) else {
          throw NativeClientError.message("The server did not confirm the edit.")
        }
        let response = try await wire.decode(bytes)
        await accept(response)
        offset += count
      }
      failedWrites = []
      error = ""
      notice = "Saved"
      if showTable { await loadTable() }
      return true
    } catch {
      failedWrites = Array(writes.dropFirst(offset))
      self.error =
        "\(offset) cells confirmed; \(failedWrites.count) still need saving. "
        + error.localizedDescription
      return false
    }
  }
  func retryWrites() async {
    let pending = failedWrites
    if await write(pending, retrying: true), pending.count == 1, let value = pending.first,
      value.r == selection.start.r, value.c == selection.start.c, value.raw == draft
    {
      originalDraft = draft
    }
  }
}