//// The repo-storage envelope around any generated record type: addressing
//// (`uri`/`cid`/`rkey`) plus the decoded record `value`. Not a lexicon concept,
//// so it's hand-written and generic over the record.

import atproto/uri
import gleam/dynamic/decode
import gleam/json

pub type StoredItem(record) {
  StoredItem(uri: String, cid: String, rkey: String, value: record)
}

/// Build a `StoredItem` for a `listRecords` row, deriving `rkey` from the
/// record's at-uri. The single home for that derivation, shared by the row
/// decoder below and by callers that already hold a decoded value.
pub fn stored_row(
  at_uri: String,
  cid: String,
  value: record,
) -> StoredItem(record) {
  StoredItem(uri: at_uri, cid:, rkey: uri.rkey(at_uri), value:)
}

/// Decode one `com.atproto.repo.listRecords` row (`uri`/`cid`/`value`) into a
/// `StoredItem`. `value_decoder` decodes the row's record body.
pub fn list_records_row_decoder(
  value_decoder: decode.Decoder(record),
) -> decode.Decoder(StoredItem(record)) {
  use at_uri <- decode.field("uri", decode.string)
  use cid <- decode.field("cid", decode.string)
  use value <- decode.field("value", value_decoder)
  decode.success(stored_row(at_uri, cid, value))
}

pub fn encode_stored_item(
  stored: StoredItem(record),
  encode_value: fn(record) -> json.Json,
) -> json.Json {
  json.object([
    #("uri", json.string(stored.uri)),
    #("cid", json.string(stored.cid)),
    #("rkey", json.string(stored.rkey)),
    #("value", encode_value(stored.value)),
  ])
}

pub fn stored_item_decoder(
  value_decoder: decode.Decoder(record),
) -> decode.Decoder(StoredItem(record)) {
  use uri <- decode.field("uri", decode.string)
  use cid <- decode.field("cid", decode.string)
  use rkey <- decode.field("rkey", decode.string)
  use value <- decode.field("value", value_decoder)
  decode.success(StoredItem(uri:, cid:, rkey:, value:))
}