Line chart

"use client"

import * as React from "react"
import { CartesianGrid, Line, LineChart as RechartsLineChart, XAxis, YAxis } from "recharts"

import { cn } from "@/lib/utils"
import {
  ChartLegend,
  ChartLegendContent,
  ChartTooltip,
  ChartTooltipContent,
} from "@/components/ui/chart"
import {
  ACTIVE_DOT,
  AXIS_TICK,
  axisProps,
  buildChartConfig,
  chartDefaults,
  chartRows,
  chartSummary,
  type CommonChartProps,
  defaultIndexFormatter,
  defaultValueFormatter,
  GRID_PROPS,
  STROKE_WIDTH,
  tooltipIndexLabel,
} from "@/components/ui/chart-core"
import { renderAnnotations } from "@/components/ui/chart-annotations"
import { ChartPlot, ChartRows } from "@/components/ui/chart-frame"
import {
  annotationHeadroom,
  directLabel,
  inlineLabelWidth,
  legendPlacement,
} from "@/components/ui/chart-labels"
import { COMPARE_STROKE, compareSeries, tooltipRow } from "@/components/ui/chart-tooltip"
import { type ChartBaseline, yAxisScale } from "@/components/ui/chart-scale"

export type LineChartProps = CommonChartProps & {
  /**
   * Where the value axis starts. `zero` takes zero in, as every chart does by
   * default; `auto` fits the axis to the data's own range, for a level — a
   * rate, a price — whose movement a zero floor would flatten.
   */
  baseline?: ChartBaseline
  curve?: "monotone" | "linear" | "step"
  /** Marks every point, not just the one under the pointer. Best under ~20 points. */
  dots?: boolean
  strokeWidth?: number
}

function LineChart({
  className,
  data,
  index,
  series,
  valueFormatter = defaultValueFormatter,
  indexFormatter = defaultIndexFormatter,
  height = chartDefaults.height,
  showLegend = chartDefaults.showLegend,
  showGrid = chartDefaults.showGrid,
  showXAxis = chartDefaults.showXAxis,
  showYAxis = chartDefaults.showYAxis,
  showTooltip = chartDefaults.showTooltip,
  legend = chartDefaults.legend,
  annotations,
  compare = false,
  baseline = "zero",
  curve = "monotone",
  dots = false,
  strokeWidth = STROKE_WIDTH,
  ...props
}: LineChartProps) {
  const ghosts = React.useMemo(() => compareSeries(series, compare), [series, compare])
  const config = React.useMemo(() => buildChartConfig([...series, ...ghosts]), [series, ghosts])
  const rows = chartRows({ data, index, series, valueFormatter, indexFormatter })
  const scale = yAxisScale(data, series, { compare, annotations, baseline })
  const summary = chartSummary("Line chart", { data, index, series, indexFormatter })
  const inline = showLegend ? legend : "none"

  return (
    <div
      data-slot="line-chart"
      data-baseline={baseline}
      data-curve={curve}
      data-dots={dots || undefined}
      className={cn("w-full", className)}
      {...props}
    >
      <ChartPlot
        height={height}
        config={config}
        role="img"
        aria-label={summary}
        className="aspect-auto w-full"
      >
        {(frame) => {
          const placement = legendPlacement(inline, series, frame.width)
          return (
          <RechartsLineChart
            // Named once, by the container's role="img" and its summary; recharts'
            // keyboard layer would add an unnamed role="application" tab stop inside it.
            accessibilityLayer={false}
            data={data}
            margin={{ top: annotationHeadroom(annotations), right: inlineLabelWidth(series, placement), bottom: 0, left: 12 }}
          >
            {showGrid ? <CartesianGrid vertical={false} {...GRID_PROPS} /> : null}

            {showXAxis ? (
              <XAxis
                tick={AXIS_TICK}
                dataKey={index}
                {...axisProps}
                minTickGap={16}
                tickFormatter={(value) => indexFormatter(value)}
              />
            ) : null}

            {frame.yAxis(showYAxis) ? (
              <YAxis
                tick={AXIS_TICK}
                {...axisProps}
                width="auto"
                domain={scale.domain}
                ticks={scale.ticks}
                tickFormatter={(value) => valueFormatter(Number(value))}
              />
            ) : baseline === "auto" ? (
              // No printed scale in a box this small, but a fitted plot still
              // has to span the data's range rather than recharts' own 0-up one.
              <YAxis hide domain={scale.domain} />
            ) : null}

            {showTooltip ? (
              <ChartTooltip
                content={
                  <ChartTooltipContent
                    labelFormatter={(_, payload) => tooltipIndexLabel(payload, index, indexFormatter)}
                    formatter={tooltipRow({ valueFormatter, series, compare })}
                  />
                }
              />
            ) : null}

            {/* The period before this one, behind its own series and dimmed. */}
            {ghosts.map((entry) => (
              <Line
                key={entry.key}
                dataKey={entry.key}
                name={entry.label}
                type={curve}
                stroke={`var(--color-${entry.key})`}
                {...COMPARE_STROKE}
              />
            ))}

            {series.map((entry) => (
              <Line
                key={entry.key}
                dataKey={entry.key}
                name={entry.label}
                type={curve}
                stroke={`var(--color-${entry.key})`}
                strokeWidth={strokeWidth}
                strokeLinecap="round"
                strokeLinejoin="round"
                // A hollow dot: the series' own ring around the surface the
                // chart sits on (--chart-surface, falling back to the card), so
                // a marker reads as a point on the line rather than a bead.
                dot={dots ? { r: 4, strokeWidth: 2, fill: "var(--chart-surface, var(--card))" } : false}
                activeDot={ACTIVE_DOT}
                isAnimationActive={false}
              >
                {directLabel(entry, { legend: placement, count: data.length })}
              </Line>
            ))}

            {renderAnnotations(annotations)}

            {showLegend && placement === "bottom" && series.length > 1 ? (
              <ChartLegend content={<ChartLegendContent />} />
            ) : null}
          </RechartsLineChart>
          )
        }}
      </ChartPlot>

      <ChartRows
        slot="line-chart-data"
        label="Line chart data"
        rows={rows}
        annotations={annotations}
        valueFormatter={valueFormatter}
        indexFormatter={indexFormatter}
      />
    </div>
  )
}

export { LineChart }

import * as React from "react"

import { formatNumber } from "@/lib/format"
import type { ChartConfig } from "@/components/ui/chart"
import { isChartToken, type ChartToken } from "@/components/ui/percentage-bar"

/** One point of a chart: the index value plus one number per series key. */
export type ChartDatum = Record<string, string | number | null | undefined>

/** One plotted measure — which key to read, what to call it, what to paint it. */
export type ChartSeries = {
  key: string
  label: string
  /** A chart token, or any CSS colour for a brand hue. Defaults to the palette in order. */
  color?: ChartToken | string
  /**
   * The key holding the same measure over the period before this one. Drawn as
   * a dashed ghost behind the series and printed in its tooltip row as a delta.
   */
  compareKey?: string
  /**
   * The colour the ghost is drawn in: a chart token or any CSS colour. Left
   * out, the ghost wears the series' own colour; `var(--chart-neutral)` keeps
   * the period before out of the palette, grey under every preset — including
   * one whose first slot follows a coloured accent.
   */
  compareColor?: ChartToken | string
}

/** The props every cartesian chart in the set accepts. */
export type CommonChartProps = React.ComponentProps<"div"> & {
  data: ChartDatum[]
  /** The key holding each point's category — the month, the day, the source. */
  index: string
  series: ChartSeries[]
  /** Formats every number the chart prints: axis ticks, tooltips, and the text summary. */
  valueFormatter?: (n: number) => string
  /** Formats every index label, e.g. an ISO date into "Sep 4". */
  indexFormatter?: (v: string | number) => string
  /** Plot height in pixels, axis band included. */
  height?: number
  showLegend?: boolean
  showGrid?: boolean
  showXAxis?: boolean
  showYAxis?: boolean
  showTooltip?: boolean
  /** Where the series are named: beside their last point, under the plot, or nowhere. */
  legend?: ChartLegendPlacement
  /** Goal lines, event markers and bands drawn over the plot and read out as text. */
  annotations?: ChartAnnotation[]
  /** Draws each series' `compareKey` as a dashed ghost behind it, in the series' `compareColor` if it names one, its own colour if not. */
  compare?: boolean
  className?: string
}

// The palette wraps rather than inventing a ninth hue: past eight series the
// colours stop being distinguishable, so fold the tail into an "Other" series.
const PALETTE_SIZE = 8

/**
 * A series' colour: a chart token becomes its CSS variable, any other string is
 * taken as a raw CSS colour, and a series that names none takes the next slot in
 * the palette, wrapping past the eighth.
 */
export function seriesColor(series: ChartSeries, i: number): string {
  const color = series.color
  if (color === undefined) return `var(--chart-${(i % PALETTE_SIZE) + 1})`
  return isChartToken(color) ? `var(--${color})` : color
}

/**
 * The ChartConfig the chart primitive needs — it turns each entry into a
 * `--color-<key>` custom property that recharts marks reference.
 */
export function buildChartConfig(series: ChartSeries[]): ChartConfig {
  // fromEntries defines own properties, so a series keyed "__proto__" lands as
  // data instead of reassigning the config object's prototype.
  return Object.fromEntries(
    series.map((entry, i) => [entry.key, { label: entry.label, color: seriesColor(entry, i) }])
  )
}

/**
 * The shared starting point: a 280px plot with both axes, a grid, direct labels
 * at the end of each series, and a tooltip. The value axis is on — a chart
 * without a printed scale is a shape, not a measurement — and the charts turn it
 * off themselves when the plot is too small to carry one (`fitsYAxis`).
 */
export const chartDefaults = {
  height: 280,
  showLegend: true,
  showGrid: true,
  showXAxis: true,
  showYAxis: true,
  showTooltip: true,
  legend: "inline-end",
} as const

/**
 * A drawn line: 2px with round caps and joins reads as a stroke at any size
 * and holds its own on a white sheet, where 1.5px thinned to a hair on a
 * high-density screen.
 */
export const STROKE_WIDTH = 2

/**
 * The gridline: the grid token, dashed, so a rule under the data reads as a
 * guide rather than as a border. Every cartesian chart spreads this onto its
 * CartesianGrid.
 */
export const GRID_PROPS = { stroke: "var(--chart-grid)", strokeDasharray: "3 3" } as const

/**
 * The dot under the pointer: 3.5px of the series' own colour, ringed in the
 * surface it sits on so it stays legible where two lines cross.
 * --chart-surface falls back to the card a chart normally lives on; set it on
 * any ancestor when the chart sits on another plane.
 */
export const ACTIVE_DOT = { r: 3.5, strokeWidth: 2, stroke: "var(--chart-surface, var(--card))" } as const

/**
 * The corner a column turns, and the gap between two segments of one stack. A
 * stack is rounded as one shape — the top corners on the topmost segment, the
 * bottom corners on the lowest — so a bar reads as a printed block rather than
 * a pile of separately rounded tiles.
 */
export const BAR_RADIUS = 6
export const BAR_GAP = 1

/** Axis chrome: no rule and no tick marks, so only the labels carry the scale. */
export const axisProps = { tickLine: false, axisLine: false, tickMargin: 8, fontSize: 12 } as const

/**
 * The paint every axis label takes: --chart-axis, the token §3.8 names for the
 * printed scale. recharts writes fill="#666" onto its own
 * tick text, and the primitive's `.recharts-cartesian-axis-tick text` rule does
 * not reach it — recharts 3 nests labels under
 * `.recharts-cartesian-axis-tick-labels` instead — so #666 survived on the card
 * at 3.16:1 in dark. Passing the fill as a tick prop puts it on the element
 * itself, where nothing has to match a selector.
 */
export const AXIS_TICK = { fill: "var(--chart-axis)" } as const

/** Chart numbers fall back to thousands-separated values when no valueFormatter is given. */
export function defaultValueFormatter(value: number): string {
  return formatNumber(value)
}

/** Index labels print as they arrive unless the chart is given an indexFormatter. */
export function defaultIndexFormatter(value: string | number): string {
  return String(value)
}

/** What the text helpers need to turn a chart's data back into words. */
export type ChartTextOptions = {
  data: ChartDatum[]
  index: string
  series: ChartSeries[]
  valueFormatter?: (n: number) => string
  indexFormatter?: (v: string | number) => string
}

function readIndex(datum: ChartDatum, index: string, format: (v: string | number) => string) {
  const raw = datum[index]
  return typeof raw === "string" || typeof raw === "number" ? format(raw) : ""
}

function readValue(raw: ChartDatum[string], format: (n: number) => string) {
  return typeof raw === "number" && Number.isFinite(raw) ? format(raw) : "no data"
}

function joinLabels(labels: string[]): string {
  if (labels.length < 2) return labels.join("")
  return `${labels.slice(0, -1).join(", ")} and ${labels[labels.length - 1]}`
}

/**
 * The plotted data as text, one row per point. Every chart renders this into a
 * visually hidden list, so the numbers are readable without pointing at a tooltip.
 */
export function chartRows(options: ChartTextOptions): { label: string; readings: string }[] {
  const {
    data,
    index,
    series,
    valueFormatter = defaultValueFormatter,
    indexFormatter = defaultIndexFormatter,
  } = options

  return data.map((datum) => ({
    label: readIndex(datum, index, indexFormatter),
    readings: series
      .map((entry) => `${entry.label} ${readValue(datum[entry.key], valueFormatter)}`)
      .join(", "),
  }))
}

/**
 * The heading for a tooltip: the point's own index value, read straight off the
 * datum. The primitive resolves its label through the config, which only works
 * when the index is a string — reading the datum keeps numeric indexes intact.
 */
export function tooltipIndexLabel(
  payload: ReadonlyArray<{ payload?: unknown }> | undefined,
  index: string,
  format: (v: string | number) => string = defaultIndexFormatter
): string {
  const datum = payload?.[0]?.payload
  const raw = datum && typeof datum === "object" ? (datum as ChartDatum)[index] : undefined
  return typeof raw === "string" || typeof raw === "number" ? format(raw) : ""
}

/** A one-sentence description of what a chart plots, used as its accessible name. */
export function chartSummary(kind: string, options: ChartTextOptions): string {
  const { data, index, series, indexFormatter = defaultIndexFormatter } = options
  if (series.length === 0) return `${kind} with no series.`

  const labels = joinLabels(series.map((entry) => entry.label))
  if (data.length === 0) return `${kind} of ${labels} by ${index}. No data.`

  const first = readIndex(data[0], index, indexFormatter)
  const last = readIndex(data[data.length - 1], index, indexFormatter)
  const count = `${data.length} point${data.length === 1 ? "" : "s"}`
  return `${kind} of ${labels} by ${index}, ${count} from ${first} to ${last}.`
}

/* -------------------------------------------------------------------------- */
/* Annotations                                                                 */
/* -------------------------------------------------------------------------- */

/** Where a chart names its series. */
export type ChartLegendPlacement = "inline-end" | "bottom" | "none"

/** The meanings an annotation can carry; each resolves to a token, never a literal. */
export type ChartAnnotationTone = "neutral" | "brand" | "positive" | "negative" | "warning" | "info"

export type ChartAnnotation =
  /** A threshold across the plot: a goal, a limit, an included allowance. */
  | { kind: "line"; axis?: "x" | "y"; value: number | string; label: string; tone?: ChartAnnotationTone }
  /** A moment on the index axis: a launch, a deploy, an incident. */
  | { kind: "event"; x: number | string; label: string; tone?: ChartAnnotationTone; href?: string }
  /**
   * A stretch of the index axis: a freeze, an outage, a campaign. The label
   * reads from the band's start; `align: "end"` hangs it from the band's end
   * instead, for a band that runs to the edge of the plot — a 59px word over
   * a 30px band at the right edge otherwise runs out of the plot.
   */
  | {
      kind: "band"
      from: number | string
      to: number | string
      label: string
      tone?: ChartAnnotationTone
      align?: "start" | "end"
    }

const ANNOTATION_PAINT: Record<ChartAnnotationTone, string> = {
  neutral: "var(--faint-foreground)",
  brand: "var(--brand)",
  positive: "var(--chart-positive)",
  negative: "var(--chart-negative)",
  warning: "var(--warning)",
  info: "var(--info)",
}

/**
 * The paint a *meaning* takes, as opposed to a category.
 *
 * A series that is coded by status — 200/429/500, up/down, paid/overdue — is
 * not one of eight interchangeable hues: it has to resolve to the semantic
 * tokens, or a reader learns the wrong colour for "failed" on one page and
 * carries it to the next. Categories keep the palette; meanings come from here.
 */
export const CHART_TONES = {
  positive: "var(--chart-positive)",
  negative: "var(--chart-negative)",
  neutral: "var(--chart-neutral)",
  warning: "var(--warning)",
  info: "var(--info)",
} as const

export type ChartTone = keyof typeof CHART_TONES

export function chartTone(tone: ChartTone): string {
  return CHART_TONES[tone]
}

/** The token an annotation's tone paints in. */
export function annotationPaint(tone: ChartAnnotationTone = "neutral"): string {
  return ANNOTATION_PAINT[tone] ?? ANNOTATION_PAINT.neutral
}

/** The numbers an annotation pins to the value axis, so the scale can hold them. */
export function annotationValues(annotation: ChartAnnotation): number[] {
  if (annotation.kind === "line" && annotation.axis !== "x" && typeof annotation.value === "number")
    return [annotation.value]
  return []
}

/**
 * Every annotation as a line of text, appended to a chart's visually hidden
 * rows: a goal line a sighted reader can see has to be readable too.
 */
export function annotationRows(
  annotations: ChartAnnotation[] = [],
  options: {
    valueFormatter?: (n: number) => string
    indexFormatter?: (v: string | number) => string
  } = {}
): string[] {
  const {
    valueFormatter = defaultValueFormatter,
    indexFormatter = defaultIndexFormatter,
  } = options
  const at = (value: number | string) =>
    typeof value === "number" ? valueFormatter(value) : indexFormatter(value)

  return annotations.map((annotation) => {
    if (annotation.kind === "line")
      return `${annotation.label}: ${
        annotation.axis === "x" ? indexFormatter(annotation.value) : at(annotation.value)
      }`
    if (annotation.kind === "event") return `${annotation.label} at ${indexFormatter(annotation.x)}`
    return `${annotation.label}: ${indexFormatter(annotation.from)} to ${indexFormatter(annotation.to)}`
  })
}

import {
  annotationValues,
  type ChartAnnotation,
  type ChartDatum,
  type ChartSeries,
} from "@/components/ui/chart-core"

// A printed scale lands on steps a reader can add up in their head. Anything
// else — recharts' own 0/650/1.3K/2K/2.6K — makes the reader do arithmetic to
// place a point between two gridlines.
const NICE_STEPS = [1, 2, 2.5, 5, 10] as const

/** Rounds a rough interval up to the next 1, 2, 2.5 or 5 × 10ⁿ. */
export function niceStep(rough: number): number {
  if (!Number.isFinite(rough) || rough <= 0) return 1
  const magnitude = 10 ** Math.floor(Math.log10(rough))
  const scaled = rough / magnitude
  const step = NICE_STEPS.find((candidate) => scaled <= candidate * (1 + 1e-9)) ?? 10
  return step * magnitude
}

// Summing a float step accumulates error, so each tick is computed from the
// index and then snapped back to the precision the step itself carries.
const snap = (value: number): number => Number(value.toPrecision(12))

/**
 * Where a value axis starts. `zero` — the default everywhere — always takes
 * zero in, because a count, a sum or a share is read against nothing, and a
 * bar that does not start there lies about its length. `auto` fits the axis
 * to the data's own range, on the same nice steps, for a level whose
 * movement is the reading — a rate, a price, a temperature — and which a
 * zero floor would flatten into a line along the top of the plot.
 */
export type ChartBaseline = "zero" | "auto"

/** Ticks from `bottom` to `top` on `step`, both ends included. */
function ticksBetween(bottom: number, top: number, step: number): number[] {
  const ticks: number[] = []
  for (let i = 0; bottom + i * step <= top + step / 2; i += 1) ticks.push(snap(bottom + i * step))
  return ticks
}

/** The ticks and the domain for a range, on nice steps, both ends included. */
export function niceDomain(
  min: number,
  max: number,
  count = 4,
  options: { baseline?: ChartBaseline } = {}
): { domain: [number, number]; ticks: number[] } {
  if (options.baseline === "auto") return fittedDomain(min, max, count)

  const low = Math.min(0, Number.isFinite(min) ? min : 0)
  const high = Math.max(Number.isFinite(max) ? max : 0, low)
  // A flat series at zero still needs two gridlines, or the plot has no scale.
  if (high === low) return { domain: [low, low + 1], ticks: [low, low + 1] }

  const step = niceStep((high - low) / Math.max(1, count))
  const bottom = Math.floor(low / step + 1e-9) * step
  const top = Math.ceil(high / step - 1e-9) * step
  return { domain: [snap(bottom), snap(top)], ticks: ticksBetween(bottom, top, step) }
}

/**
 * The `auto` baseline: the data's own range, widened out to the nice steps
 * either side of it, so 1.05–1.11 prints 1.04 / 1.06 / … / 1.12 rather than
 * 0 / 0.5 / 1 / 1.5. A flat level still gets a scale — a step either side of
 * it — and nothing to plot falls back to the zero baseline's 0 / 1.
 *
 * A peak drawn on the frame's edge reads as clipped, so an extreme within a
 * quarter of a step of the edge gets one step more: 1.05–1.12 prints up to
 * 1.14. That air never takes the axis across zero, which a level that does
 * not cross it has no business reaching past.
 */
function fittedDomain(min: number, max: number, count: number): { domain: [number, number]; ticks: number[] } {
  const lowest = Number.isFinite(min) ? min : 0
  const highest = Number.isFinite(max) ? Math.max(max, lowest) : lowest
  let low = lowest
  let high = highest
  if (high === low) {
    if (low === 0) return niceDomain(0, 0, count)
    const pad = niceStep(Math.abs(low) / 10)
    low -= pad
    high += pad
  }

  const step = niceStep((high - low) / Math.max(1, count))
  let bottom = Math.floor(low / step + 1e-9) * step
  let top = Math.ceil(high / step - 1e-9) * step
  if (lowest - bottom < step / 4) bottom = lowest >= 0 ? Math.max(0, bottom - step) : bottom - step
  if (top - highest < step / 4) top = highest <= 0 ? Math.min(0, top + step) : top + step
  return { domain: [snap(bottom), snap(top)], ticks: ticksBetween(bottom, top, step) }
}

/** The printed scale from 0 to `max`: `niceTicks(2_900, 4)` is 0, 1000, 2000, 3000. */
export function niceTicks(max: number, count = 4): number[] {
  return niceDomain(0, max, count).ticks
}

/**
 * The lowest and highest number a set of series reaches, stacked or laid over
 * one another. On the zero baseline the extent always takes zero in, so a
 * hole in the data or a series of nothing reads as 0 / 0; on `auto` it is the
 * data's own range, and ±Infinity when there is nothing to read.
 */
export function chartExtent(
  data: ChartDatum[],
  series: ChartSeries[],
  options: { stacked?: boolean; compare?: boolean; baseline?: ChartBaseline } = {}
): { min: number; max: number } {
  const keys = series.flatMap((entry) =>
    options.compare && entry.compareKey ? [entry.key, entry.compareKey] : [entry.key]
  )
  const fitted = options.baseline === "auto"
  let min = fitted ? Infinity : 0
  let max = fitted ? -Infinity : 0
  for (const datum of data) {
    let stack = 0
    // A row of holes is no stack at all — not a stack of zero, which a
    // fitted axis would otherwise have to reach down to.
    let stacked = false
    for (const key of keys) {
      const raw = datum[key]
      if (typeof raw !== "number" || !Number.isFinite(raw)) continue
      if (options.stacked) {
        stack += raw
        stacked = true
      } else {
        if (raw < min) min = raw
        if (raw > max) max = raw
      }
    }
    if (stacked) {
      if (stack < min) min = stack
      if (stack > max) max = stack
    }
  }
  return { min, max }
}

/** A y axis' explicit domain and ticks for the data it has to hold. */
export function yAxisScale(
  data: ChartDatum[],
  series: ChartSeries[],
  options: {
    stacked?: boolean
    compare?: boolean
    count?: number
    annotations?: ChartAnnotation[]
    /** Where the axis starts; zero unless the chart asks to fit its data. */
    baseline?: ChartBaseline
  } = {}
): { domain: [number, number]; ticks: number[] } {
  const { min, max } = chartExtent(data, series, options)
  // A goal line above every plotted point still has to fit inside the plot.
  let low = min
  let high = max
  for (const annotation of options.annotations ?? []) {
    for (const value of annotationValues(annotation)) {
      if (value < low) low = value
      if (value > high) high = value
    }
  }
  return niceDomain(low, high, options.count ?? 4, { baseline: options.baseline })
}

// Below these the axis band costs more than the scale it prints: the labels
// crowd the plot at 120px tall and eat a third of the width at 240px wide.
const MIN_AXIS_HEIGHT = 120
const MIN_AXIS_WIDTH = 240

/**
 * Whether a y axis fits. Width 0 means "not measured yet" — on the server, and
 * in a test with no layout — and is never taken as "too narrow".
 */
export function fitsYAxis(height: number, width = 0): boolean {
  if (height < MIN_AXIS_HEIGHT) return false
  return width === 0 || width >= MIN_AXIS_WIDTH
}

"use client"

import * as React from "react"

import { cn } from "@/lib/utils"
import { useReducedMotion } from "@/hooks/use-reduced-motion"
import { ChartContainer } from "@/components/ui/chart"
import { annotationRows, type ChartAnnotation } from "@/components/ui/chart-core"
import { fitsYAxis } from "@/components/ui/chart-scale"
import { ChartSkeleton } from "@/components/ui/loading-skeletons"

/* -------------------------------------------------------------------------- */
/* The frame: measure, then draw                                              */
/* -------------------------------------------------------------------------- */


// A ChartSkeleton is a legend, a plot and a row of tick labels; the two text
// rows and their gaps take about this much, so the skeleton reserves the same
// box the finished chart will fill.
const SKELETON_CHROME = 56

/** What a chart's body is told about the box it is being drawn into. */
export type ChartFrame = {
  /** The plot's own width in px, or 0 before it has been measured. */
  width: number
  /** False until one layout has happened — the skeleton holds the space until then. */
  measured: boolean
  reduced: boolean
  /** Whether the value axis both was asked for and fits in the box. */
  yAxis: (asked: boolean) => boolean
}

export type ChartPlotProps = Omit<React.ComponentProps<typeof ChartContainer>, "children"> & {
  height: number
  /** The recharts chart to draw, given what is known about the box. */
  children: (frame: ChartFrame) => React.ComponentProps<typeof ChartContainer>["children"]
}

/**
 * A chart's box: measured first, drawn second.
 *
 * Nothing can be measured on the server, so the skeleton holds the chart's
 * space until the first client layout, and the ChartContainer inside then
 * measures its own box and draws at that size — which is also what makes the
 * mount fade a fade of the finished chart rather than of a mis-sized one. The
 * width measured here is what decides whether a value axis fits, so that
 * decision is handed to the chart body rather than guessed at.
 */
function ChartPlot({ height, className, style, children, ...props }: ChartPlotProps) {
  const [width, setWidth] = React.useState(0)
  const [measured, setMeasured] = React.useState(false)
  const plot = React.useRef<HTMLDivElement | null>(null)
  // Asked of the plot itself, so a frame that asked for less motion on its own
  // wrapper is heard; the document root would not have carried it.
  const reduced = useReducedMotion(plot)

  const ref = React.useCallback((node: HTMLDivElement | null) => {
    plot.current = node
    if (!node) return
    const read = () => setWidth(Math.round(node.getBoundingClientRect().width))
    read()
    // One layout has now happened, whether or not it produced a number: an
    // environment with no layout engine reports 0 forever, and holding a
    // skeleton there would mean no chart is ever drawn at all.
    setMeasured(true)
    if (typeof ResizeObserver !== "function") return
    const observer = new ResizeObserver(read)
    observer.observe(node)
    return () => observer.disconnect()
  }, [])

  return (
    <div ref={ref} data-slot="chart-plot" className="w-full">
      {measured ? (
        <ChartContainer
          // The one piece of motion a chart has: it fades in when it first has a
          // size, and never again — a re-render on new data leaves the element
          // mounted, so the animation does not restart. Duration and easing are
          // the theme's tokens, which are zeroed under reduced motion.
          className={cn(
            !reduced && "animate-in fade-in-0 duration-(--duration-base) ease-(--ease-standard)",
            className
          )}
          style={{ height, ...style }}
          {...props}
        >
          {children({
            width,
            measured,
            reduced,
            yAxis: (asked: boolean) => asked && fitsYAxis(height, width),
          })}
        </ChartContainer>
      ) : (
        <ChartSkeleton height={Math.max(80, height - SKELETON_CHROME)} />
      )}
    </div>
  )
}

export type ChartRowsProps = {
  slot: string
  label: string
  rows: { label: string; readings: string }[]
  annotations?: ChartAnnotation[]
  valueFormatter?: (n: number) => string
  indexFormatter?: (v: string | number) => string
}

/**
 * A chart's numbers as text. Every plotted point, then every annotation drawn
 * over them — a goal line a sighted reader can see has to be readable too.
 */
function ChartRows({
  slot,
  label,
  rows,
  annotations,
  valueFormatter,
  indexFormatter,
}: ChartRowsProps) {
  const notes = annotationRows(annotations, { valueFormatter, indexFormatter })

  return (
    <ul data-slot={slot} aria-label={label} className="sr-only">
      {rows.map((row, i) => (
        <li key={`row-${i}`}>{`${row.label}: ${row.readings}`}</li>
      ))}
      {notes.map((note, i) => (
        <li key={`note-${i}`} data-slot="chart-annotation-row">
          {note}
        </li>
      ))}
    </ul>
  )
}


export { ChartPlot, ChartRows }

"use client"

import * as React from "react"
import { ReferenceArea, ReferenceLine } from "recharts"

import { annotationPaint, type ChartAnnotation } from "@/components/ui/chart-core"

/* -------------------------------------------------------------------------- */
/* Annotations                                                                 */
/* -------------------------------------------------------------------------- */


// The eyebrow register, drawn in SVG: 11px, 600, the tone's own ink.
const EYEBROW = {
  fontSize: 11,
  fontWeight: 600,
  letterSpacing: "0.06em",
} as const

/** The one dash on a chart: reference lines and the compare ghost share it. */
export const DASH = "4 4"

/**
 * A halo round a label in the plane the chart sits on: the stroke is painted
 * under the fill, so the words stay legible where they cross a column, a
 * line or the wash under an area. --chart-surface falls back to the card, as
 * the active dot's ring does.
 */
export const LABEL_HALO = {
  stroke: "var(--chart-surface, var(--card))",
  strokeWidth: 4,
  strokeLinejoin: "round",
  paintOrder: "stroke",
} as const

function annotationLabel(
  text: string,
  paint: string,
  position: "insideTopLeft" | "insideTopRight" | "top"
) {
  return {
    value: text.toUpperCase(),
    position,
    fill: paint,
    offset: 6,
    ...EYEBROW,
    ...LABEL_HALO,
  }
}

/**
 * Goal lines, event markers and bands as recharts elements.
 *
 * An array rather than a fragment: recharts reads its children by type, and
 * `React.Children` flattens an array into that list while a fragment arrives as
 * one opaque child it does not look inside.
 */
export function renderAnnotations(
  annotations: ChartAnnotation[] = [],
  options: { yAxisId?: string } = {}
): React.ReactElement[] {
  const { yAxisId } = options

  return annotations.map((annotation, i) => {
    const paint = annotationPaint(annotation.tone)

    if (annotation.kind === "band") {
      return (
        <ReferenceArea
          key={`band-${i}`}
          yAxisId={yAxisId}
          x1={annotation.from}
          x2={annotation.to}
          fill={paint}
          fillOpacity={0.1}
          stroke="none"
          aria-label={annotation.label}
          label={annotationLabel(
            annotation.label,
            paint,
            annotation.align === "end" ? "insideTopRight" : "insideTopLeft"
          )}
        />
      )
    }

    if (annotation.kind === "event") {
      return (
        <ReferenceLine
          key={`event-${i}`}
          yAxisId={yAxisId}
          x={annotation.x}
          stroke={paint}
          strokeWidth={1}
          strokeDasharray={DASH}
          label={annotationLabel(annotation.label, paint, "top")}
        />
      )
    }

    const onX = annotation.axis === "x"
    return (
      <ReferenceLine
        key={`line-${i}`}
        yAxisId={yAxisId}
        x={onX ? annotation.value : undefined}
        y={onX ? undefined : annotation.value}
        stroke={paint}
        strokeWidth={1}
        strokeDasharray={DASH}
        label={annotationLabel(annotation.label, paint, onX ? "top" : "insideTopLeft")}
      />
    )
  })
}

"use client"

import * as React from "react"
import { LabelList } from "recharts"

import {
  type ChartAnnotation,
  type ChartLegendPlacement,
  type ChartSeries,
} from "@/components/ui/chart-core"

/* -------------------------------------------------------------------------- */
/* Direct labels                                                               */
/* -------------------------------------------------------------------------- */


// An 8px swatch and 12px text: the series colour carries the identity and the
// ink carries the reading, because slots 5–8 as 13px coloured text miss AA.
const SWATCH = 8
const LABEL_GAP = 6
const CHAR_WIDTH = 6.4

type DirectLabelProps = {
  x?: number
  y?: number
  index?: number
  last?: number
  text?: string
  paint?: string
}

function DirectLabelMark({ x = 0, y = 0, index, last, text = "", paint }: DirectLabelProps) {
  if (index !== last) return null

  return (
    <g transform={`translate(${x + LABEL_GAP}, ${y})`} data-slot="chart-direct-label">
      <rect y={-SWATCH / 2} width={SWATCH} height={SWATCH} rx={2} fill={paint} />
      <text
        x={SWATCH + 4}
        dy="0.32em"
        fill="var(--foreground)"
        fontSize={12}
        data-slot="chart-direct-label-text"
      >
        {text}
      </text>
    </g>
  )
}

/**
 * A series' name set beside its own last point, so a reader never has to match a
 * swatch in a legend to a line in a plot. Returns null unless the chart is
 * drawing its legend inline, which is what makes it safe to write into every mark.
 */
export function directLabel(
  entry: ChartSeries,
  options: { legend: ChartLegendPlacement; count: number }
): React.ReactElement | null {
  if (options.legend !== "inline-end" || options.count === 0) return null

  return (
    <LabelList
      key={`label-${entry.key}`}
      dataKey={entry.key}
      content={
        <DirectLabelMark
          last={options.count - 1}
          text={entry.label}
          paint={`var(--color-${entry.key})`}
        />
      }
    />
  )
}

/**
 * The headroom an annotation label needs. A marker on the index axis writes its
 * eyebrow above the plot, and 12px of margin clips the ascender off it.
 */
export function annotationHeadroom(annotations: ChartAnnotation[] = []): number {
  return annotations.some((a) => a.kind === "event" || (a.kind === "line" && a.axis === "x"))
    ? 24
    : 12
}

/** The right margin the inline labels need, so the longest one is not clipped. */
export function inlineLabelWidth(series: ChartSeries[], legend: ChartLegendPlacement): number {
  if (legend !== "inline-end") return 12
  const longest = series.reduce((most, entry) => Math.max(most, entry.label.length), 0)
  return Math.min(180, LABEL_GAP + SWATCH + 4 + Math.ceil(longest * CHAR_WIDTH) + 8)
}

/**
 * Where the legend goes once the box is known. Inline labels that would take
 * more than a quarter of the plot — a 390px phone gave billing-usage 84px of a
 * 318px one — go under it instead; before the first measurement the answer is
 * what was asked for, so the server render and the client's first one agree.
 */
export function legendPlacement(
  asked: ChartLegendPlacement,
  series: ChartSeries[],
  width: number
): ChartLegendPlacement {
  // A lone series has no legend to fall back to — the charts draw one for two
  // or more — so it keeps its label, which is the cheaper of the two anyway.
  if (asked !== "inline-end" || width === 0 || series.length < 2) return asked
  return inlineLabelWidth(series, asked) > width / 4 ? "bottom" : asked
}


export { DirectLabelMark }

"use client"

import * as React from "react"

import { DASH } from "@/components/ui/chart-annotations"
import {
  defaultValueFormatter,
  seriesColor,
  type ChartDatum,
  type ChartSeries,
} from "@/components/ui/chart-core"
import { MetricDelta } from "@/components/ui/metric-delta"

/* -------------------------------------------------------------------------- */
/* Tooltip rows                                                                */
/* -------------------------------------------------------------------------- */


export type TooltipRowOptions = {
  valueFormatter?: (n: number) => string
  /** The chart's series, so a row can find its own compare key. */
  series?: ChartSeries[]
  compare?: boolean
}

/**
 * One tooltip row: swatch, series name, the value through the chart's own
 * formatter, and — when a compare period is drawn — how far it is from the same
 * point a period ago.
 */
export function tooltipRow(options: TooltipRowOptions = {}) {
  const { valueFormatter = defaultValueFormatter, series = [], compare = false } = options

  return function renderRow(value: unknown, name: unknown, item: unknown) {
    // recharts types the payload entry as widely as its own generics allow, so
    // the two fields this row reads are narrowed here rather than in the signature.
    const point = item as { color?: string; dataKey?: unknown; payload?: ChartDatum }
    const entry = series.find((candidate) => candidate.key === point.dataKey)
    const previous =
      compare && entry?.compareKey ? point.payload?.[entry.compareKey] : undefined
    const current = Number(value)
    const delta =
      typeof previous === "number" && previous !== 0 && Number.isFinite(current)
        ? current / previous - 1
        : undefined

    return (
      <>
        <span
          className="size-2.5 shrink-0 rounded-[2px]"
          style={{ backgroundColor: point.color }}
        />
        <div className="flex flex-1 items-center justify-between gap-3 leading-none">
          <span className="text-muted-foreground">{String(name)}</span>
          <span className="flex items-center gap-2">
            <span className="font-medium tabular-nums">{valueFormatter(current)}</span>
            {delta === undefined ? null : (
              <MetricDelta value={delta} size="sm" showIcon={false} className="text-2xs" />
            )}
          </span>
        </div>
      </>
    )
  }
}

/**
 * The ghost's stroke: dashed and dimmed, in the series' own colour — or in
 * its compareColor when it names one, as a page does to keep the period
 * before out of the palette with var(--chart-neutral). 0.75 is measured
 * rather than chosen — 0.65 of the default theme's first chart hue
 * composites to 2.73:1 on a white card and 2.96:1 on a dark one, both under
 * the 3:1 a line has to clear; 0.75 reads 3.24 light and 3.53 dark. The dash
 * is what carries the meaning anyway, so the opacity only has to stay out of
 * the way.
 */
export const COMPARE_STROKE = {
  strokeDasharray: DASH,
  strokeOpacity: 0.75,
  strokeWidth: 1.5,
  legendType: "none",
  tooltipType: "none",
  dot: false,
  activeDot: false,
  isAnimationActive: false,
} as const

/** The compare series a chart should draw behind its own: each in its series' compareColor, or the series' own colour when it names none. */
export function compareSeries(series: ChartSeries[], compare: boolean): ChartSeries[] {
  if (!compare) return []
  return series.flatMap((entry, i) =>
    entry.compareKey
      ? [{ key: entry.compareKey, label: `${entry.label} (prev)`, color: entry.compareColor ?? seriesColor(entry, i) }]
      : []
  )
}