// What a reviewer reads and does: the document list, one document's lines, and an edit.
//
// Approving and rejecting are the proposals module's own procedures; this file adds only what that
// module has no word for. A document's status and counts are computed from the two places they
// live (the document row and the proposals), never stored twice.

import { notFound } from "@conusai-kit/core"
import { type FileView, getFile, listFiles } from "@conusai-kit/files"
import { editProposal, getProposal } from "@conusai-kit/proposals"
import {
  type DocumentView,
  documents,
  LINE_TARGET_KEY,
  type LineView,
  lineChangeSchema,
  READABLE_CONTENT_TYPES,
} from "../contract/index.js"
import {
  type DocumentScope,
  type DocumentsDeps,
  lineProposals,
  lineProposalsByDocument,
  lineViewOf,
  visibleLines,
} from "./lines.js"

const PAGE = 200
const readable = (file: FileView): boolean => (READABLE_CONTENT_TYPES as readonly string[]).includes(file.contentType)

async function allFiles(deps: DocumentsDeps, scope: DocumentScope): Promise<FileView[]> {
  const found: FileView[] = []
  let cursor: string | undefined
  do {
    const page = await listFiles(deps.files, scope, { limit: PAGE, ...(cursor === undefined ? {} : { cursor }) })
    found.push(...page.files)
    cursor = page.hasMore ? page.cursor : undefined
  } while (cursor !== undefined)
  return found.filter(readable)
}

async function allDocuments(deps: DocumentsDeps, scope: DocumentScope) {
  const found = []
  let cursor: string | undefined
  do {
    const page = await deps.data
      .forScope(scope)
      .of(documents)
      .list({ limit: PAGE, ...(cursor === undefined ? {} : { cursor }) })
    found.push(...page.items)
    cursor = page.hasMore ? page.cursor : undefined
  } while (cursor !== undefined)
  return found
}

function viewOf(
  file: FileView,
  row: Awaited<ReturnType<typeof allDocuments>>[number] | undefined,
  lines: readonly LineView[],
): DocumentView {
  return {
    fileId: file.fileId,
    filename: file.filename,
    // An upload the job has not picked up yet has no row: it is queued, which is a fact about the
    // queue and not a state the module stores.
    status: row?.status ?? "queued",
    failureCode: row?.failureCode ?? null,
    pageCount: row?.pageCount ?? null,
    skippedPages: row?.skippedPages ?? [],
    pending: lines.filter((line) => line.status === "pending").length,
    approved: lines.filter((line) => line.status === "approved").length,
    uploadedAt: file.storedAt,
  }
}

export async function listDocuments(deps: DocumentsDeps, scope: DocumentScope): Promise<DocumentView[]> {
  const [files, rows] = await Promise.all([allFiles(deps, scope), allDocuments(deps, scope)])
  // The proposals of these documents only, pre-indexed by document id: one indexed read of the
  // proposals table (its target index) and a Map lookup per document, instead of the project's
  // whole queue read into memory and re-filtered for every row (O(D * P)). The list itself is
  // answered whole because the `documents.document.list` contract takes no cursor; paging it
  // through the procedure is a contract change, and the read that was unbounded was this one.
  const byDocument = await lineProposalsByDocument(
    deps,
    scope,
    rows.map((row) => row.id),
  )
  const byFile = new Map(rows.map((row) => [row.fileId, row]))
  return files.map((file) => {
    const row = byFile.get(file.fileId)
    const own = row ? visibleLines(byDocument.get(row.id) ?? []) : []
    return viewOf(file, row, own)
  })
}

export async function getDocument(
  deps: DocumentsDeps,
  scope: DocumentScope,
  fileId: string,
): Promise<{ document: DocumentView; lines: LineView[] }> {
  // NotFound for another tenant's file id and for an id nobody has: the files module answers both
  // the same way, and so does this one (spec §3.3).
  const file = await getFile(deps.files, scope, fileId)
  if (!readable(file)) throw notFound("no such document")
  const row = (
    await deps.data
      .forScope(scope)
      .of(documents)
      .list({ where: [{ field: "fileId", op: "eq", value: file.fileId }], limit: 1 })
  ).items[0]
  const lines = row ? visibleLines(await lineProposals(deps, scope, row.id)) : []
  return { document: viewOf(file, row, lines), lines }
}

/**
 * A reviewer's correction of a pending line: the proposals module replaces the proposal's change with
 * the corrected one (validated by this module's own schema, audited, and refused once decided), and
 * what is approved afterwards is what the reviewer saw. The line keeps its id.
 */
export async function editLine(
  deps: DocumentsDeps,
  scope: DocumentScope,
  input: { lineId: string; label: string; value: string },
): Promise<LineView> {
  const current = await getProposal(deps.proposals, scope, input.lineId)
  if (current.targetKey !== LINE_TARGET_KEY) throw notFound("no such line")
  const change = lineChangeSchema.parse(current.change)
  const edited = await editProposal(deps.proposals, scope, current.proposalId, {
    ...change,
    label: input.label,
    value: input.value,
    edited: true,
  })
  return lineViewOf(edited)
}