import { useMutation, useQueryClient } from "@tanstack/react-query"

import { OpenAPI, RunsService } from "@/client"
import { apiToken } from "@/lib/portal"

/**
 * How deep one page of the run list is read.
 *
 * The endpoint caps a page at 500; asking for a hundred at a time keeps the
 * first paint quick and leaves "Load more" something to do.
 */
export const PAGE = 100

/** How far the list will page before it stops offering to go deeper. */
export const LIST_CAP = 500

export type RunFilters = {
  flow?: string
  status?: string
  group?: string
}

export const runKeys = {
  all: ["runs"] as const,
  overview: ["runs", "overview"] as const,
  list: (filters: RunFilters) => ["runs", "list", filters] as const,
  detail: (id: string) => ["runs", "detail", id] as const,
  metrics: (id: string, name: string) =>
    ["runs", "detail", id, "metrics", name] as const,
  compare: (ids: string[], metric: string, x: string) =>
    ["runs", "compare", ids.join(","), metric, x] as const,
}

/** The resting surface these screens are built from, as Health names it. */
export const CARD = "rounded-lg border border-border bg-card p-4 shadow-e1"

/** The statuses a run passes through, as the filter offers them. */
export const STATUSES = [
  "queued",
  "running",
  "ok",
  "error",
  "cancelled",
  "abandoned",
] as const

/** A run that has not settled is still worth re-reading. */
export const isLive = (status: string) =>
  status === "queued" || status === "running"

export const runsInfiniteQueryOptions = (filters: RunFilters) => ({
  queryKey: runKeys.list(filters),
  queryFn: ({ pageParam }: { pageParam: number }) =>
    RunsService.readRuns({ ...filters, limit: PAGE, offset: pageParam }),
  initialPageParam: 0,
  getNextPageParam: (last: unknown[], all: unknown[][]) => {
    const read = all.reduce((total, page) => total + page.length, 0)
    // A short page is the end of the history; the cap is the end of what this
    // list will show of it.
    return last.length < PAGE || read >= LIST_CAP ? undefined : read
  },
})

/** One page of runs, for a caller that pages nothing — a pinned chart. */
export const runsListQueryOptions = (
  filters: RunFilters & { limit?: number },
) => ({
  queryKey: [...runKeys.all, "pinned", filters] as const,
  queryFn: () => RunsService.readRuns(filters),
})

export const runOverviewQueryOptions = () => ({
  queryKey: runKeys.overview,
  queryFn: () => RunsService.readOverview(),
  refetchInterval: 30_000,
})

export const runQueryOptions = (id: string) => ({
  queryKey: runKeys.detail(id),
  queryFn: () => RunsService.readRun({ runId: id }),
  // A finished run never changes again, so only a live one is polled. The
  // socket's run_finished lands the last transition either way; this covers
  // the metrics and node rows filling in while it runs.
  refetchInterval: (query: { state: { data?: { status: string } } }) =>
    query.state.data && isLive(query.state.data.status)
      ? 5_000
      : (false as const),
})

/** One run's series, or every one of them when `name` is empty. */
export const runMetricsQueryOptions = (id: string, name = "") => ({
  queryKey: runKeys.metrics(id, name),
  queryFn: () => RunsService.readMetrics({ runId: id, name }),
})

/** What a comparison can be plotted against, beside another metric's name. */
export const STEP_AXIS = "step"
export const TIME_AXIS = "time"

export const compareQueryOptions = (
  ids: string[],
  metric: string,
  x = STEP_AXIS,
  refetchInterval?: number,
) => ({
  queryKey: runKeys.compare(ids, metric, x),
  queryFn: () => RunsService.compareMetric({ ids: ids.join(","), metric, x }),
  enabled: ids.length > 0 && Boolean(metric),
  ...(refetchInterval ? { refetchInterval } : {}),
})

/**
 * How many runs one selection carries.
 *
 * The selection is the address, which is what makes a comparison a link — and
 * a URL is not a place to put five hundred 22-character ids. A chart draws
 * five of them anyway; the rest of the room is for changing your mind.
 */
export const MAX_SELECTION = 50

export function useCancelRun() {
  const client = useQueryClient()
  return useMutation({
    mutationFn: (runId: string) => RunsService.cancelRun({ runId }),
    onSuccess: () => client.invalidateQueries({ queryKey: runKeys.all }),
  })
}

/**
 * Save an artifact to disk.
 *
 * Not a plain link: `/artifacts/{digest}` takes a bearer token, which an
 * anchor cannot carry. The bytes come through fetch and leave as an object
 * URL — the same trip the browser would have made, with the header on it.
 */
export async function downloadArtifact(digest: string, name: string) {
  const token = apiToken()
  const answer = await fetch(`${OpenAPI.BASE}/api/v1/artifacts/${digest}`, {
    headers: token ? { Authorization: `Bearer ${token}` } : {},
  })
  if (!answer.ok) throw new Error(`Could not read ${name}`)
  const url = URL.createObjectURL(await answer.blob())
  const link = document.createElement("a")
  link.href = url
  link.download = name
  link.click()
  URL.revokeObjectURL(url)
}

/**
 * Why a finished run can have nothing to draw.
 *
 * A cache hit replays no emissions, so a restored node's curve is read back
 * from the run that recorded it. Deleting that run — deleting its flow does —
 * takes the curve with it, and then a reused run has a result and nothing to
 * draw. Said out loud rather than left as an empty chart, which reads as a fault.
 */
export const NO_CURVE =
  "No curve was recorded. A node restored from the cache is read back from the run that produced it, so this draws nothing once that run has been deleted — its outputs are still on the result."

/** A run id, short enough for a table cell. The tail is the random half. */
export const shortId = (id: string) => id.slice(-8)

/**
 * A series label from the comparison endpoint, cut down to fit a legend.
 *
 * It leads with the whole run id, which is 22 characters of mostly timestamp
 * beside four others.
 */
export const shortenRunLabel = (label: string) =>
  label.replace(/^\S+/, (id) => shortId(id))

/** A commit, at the length everyone reads one at. */
export const shortCommit = (commit: string) => commit.slice(0, 7)

/**
 * The parameter keys that differ across these runs.
 *
 * What makes a sweep readable: fifty runs of one flow share everything but the
 * two knobs that were swept, and those two are the only columns worth drawing.
 */
export function varyingKeys(runs: { params: Record<string, unknown> }[]) {
  if (runs.length < 2) return []
  const keys = new Set<string>()
  for (const run of runs)
    for (const key of Object.keys(run.params)) keys.add(key)
  return [...keys].filter((key) => {
    const first = JSON.stringify(runs[0].params[key])
    return runs.some((run) => JSON.stringify(run.params[key]) !== first)
  })
}

/** A parameter value, as narrow as it can be written. */
export function paramText(value: unknown): string {
  if (value === null || value === undefined) return "—"
  if (typeof value === "number" || typeof value === "boolean")
    return String(value)
  if (typeof value === "string") return value
  return JSON.stringify(value)
}

/** A run's parameters on one line, for a table cell. */
export const paramsSummary = (params: Record<string, unknown>) =>
  Object.entries(params)
    .map(([key, value]) => `${key}=${paramText(value)}`)
    .join("  ")