import { useState } from "react"

import type { WidgetDef } from "@/client"
import { cn } from "@/lib/utils"
import { BarWidget } from "./BarWidget"
import { ChartWidget } from "./ChartWidget"
import { ClockWidget } from "./ClockWidget"
import { ColorWidget } from "./ColorWidget"
import { useBoundValue } from "./dataContext"
// The grid's own rules live beside the components that use them; CSS is
// chunked per entry, so the sheet is pulled in wherever a widget is drawn.
import "./dashboard.css"
import { ForecastWidget } from "./ForecastWidget"
import { IconWidget } from "./IconWidget"
import { MediaWidget } from "./MediaWidget"
import { usePublish } from "./publish"
import { useUi } from "./ui"
import { COLOR_DTYPES, colorFormatOf } from "./ui/core/color"
import { config, num, rowsOf, text } from "./ui/core/config"

/** Widget types that put a value into the graph rather than read one. */
export const INPUT_WIDGETS = new Set([
  "button",
  "switch",
  "slider",
  "input",
  "dropdown",
  "color",
])

export type WidgetKind = WidgetDef["type"]

/**
 * What a widget can be pointed at, by payload type.
 *
 * A switch that reads a float has nothing to show and nothing safe to send, so
 * the pairing is part of the document rather than a matter of taste. The same
 * table is enforced on the server (`app/flow/dashboards.py`); a type missing
 * from it takes anything.
 */
export const WIDGET_DTYPES: Partial<Record<WidgetKind, string[]>> = {
  gauge: ["float", "int"],
  // A chart reading the engine's ring. One that queries binds a `series`
  // answer and a `record` request instead, checked in `widgetIssue`.
  chart: ["float", "int"],
  slider: ["float", "int"],
  switch: ["bool"],
  agenda: ["list"],
  notification: ["record"],
  bar: ["float", "int"],
  forecast: ["list"],
  // Either shape a colour can travel as; its `format` decides which of the two
  // this widget means, which `widgetIssue` holds the binding to.
  color: ["list", "str"],
  // A camera frame, a clip, a segment. What it draws follows the type it is
  // bound to; a plain artifact is taken as well, since the media type on the
  // reference is what says what the bytes are.
  media: ["image", "audio", "video", "artifact"],
  // An icon maps weather strings, bool hints and numbers alike, and a clock
  // binds nothing at all, so neither has a row to be held to.
}

/** Whether a message of this payload type may drive this kind of widget. */
export function acceptsDtype(kind: WidgetKind, dtype: string | undefined) {
  const allowed = WIDGET_DTYPES[kind]
  return !allowed || !dtype || allowed.includes(dtype)
}

export const WIDGET_LABELS: Record<WidgetKind, string> = {
  stat: "Value",
  gauge: "Gauge",
  chart: "Chart",
  markdown: "Text",
  agenda: "Agenda",
  notification: "Notification",
  bar: "Bar",
  icon: "Icon",
  forecast: "Forecast",
  clock: "Clock",
  media: "Media",
  button: "Button",
  switch: "Switch",
  slider: "Slider",
  input: "Input",
  dropdown: "Selector",
  color: "Colour",
}

/** Default footprint per type, in grid units. */
export const WIDGET_SIZES: Record<WidgetKind, { w: number; h: number }> = {
  stat: { w: 3, h: 2 },
  gauge: { w: 3, h: 3 },
  chart: { w: 6, h: 4 },
  markdown: { w: 6, h: 2 },
  agenda: { w: 4, h: 4 },
  notification: { w: 4, h: 2 },
  bar: { w: 4, h: 2 },
  icon: { w: 2, h: 2 },
  forecast: { w: 6, h: 2 },
  clock: { w: 3, h: 2 },
  media: { w: 4, h: 4 },
  button: { w: 3, h: 2 },
  switch: { w: 3, h: 2 },
  slider: { w: 4, h: 2 },
  input: { w: 4, h: 2 },
  dropdown: { w: 4, h: 2 },
  color: { w: 4, h: 4 },
}

/** One line of a chart, as the document stores it. */
export type Series = { message?: string; dtype?: string; label?: string }

export const seriesOf = (widget: WidgetDef): Series[] =>
  (config(widget).series ?? []) as Series[]

/**
 * What is wrong with this widget's wiring, if anything.
 *
 * Both halves are checked from the document alone — the picker records the
 * payload type it bound — so a wall panel can flag a broken tile without
 * fetching the message catalogue first.
 */
export function widgetIssue(widget: WidgetDef): string | null {
  // Neither draws a message: a clock reads the wall, markdown its own text.
  if (widget.type === "markdown" || widget.type === "clock") return null
  const cfg = config(widget)

  if (widget.type === "chart" && cfg.source === "runs") {
    const runs = (cfg.runs ?? {}) as {
      metric?: string
      flow?: string
      group?: string
      ids?: string[]
    }
    if (!runs.metric) return "This chart names no run metric yet."
    if (!runs.ids?.length && !runs.group && !runs.flow) {
      return "Say which runs: a flow, a sweep, or run ids."
    }
    return null
  }

  if (widget.type === "chart" && cfg.source === "query") {
    if (!text(cfg.request)) return "This chart does not ask for anything yet."
    if (!text(cfg.message)) return "This chart has no answer to draw yet."
    const answer = text(cfg.dtype)
    if (answer && answer !== "series") {
      return `${text(cfg.message)} is a ${answer}; a chart that queries draws a series.`
    }
    const asked = text(cfg.request_dtype)
    if (asked && asked !== "record") {
      return `${text(cfg.request)} is a ${asked}; a request is a record.`
    }
    return null
  }

  if (widget.type === "chart") {
    const series = seriesOf(widget)
    if (series.length === 0) return "This chart has no series yet."
    const wrong = series.find(
      (entry) => !entry.message || !acceptsDtype("chart", entry.dtype),
    )
    if (wrong) {
      return wrong.message
        ? `${wrong.message} is a ${wrong.dtype}; a chart can only draw numbers.`
        : "One of the series is not bound to a message."
    }
    return null
  }

  // A bar draws a row per reading, so it is judged row by row — the same way
  // a chart is judged series by series.
  if (widget.type === "bar") {
    const rows = rowsOf(widget)
    if (rows.length === 0) return "This bar has no rows yet."
    const wrong = rows.find(
      (row) => !row.message || !acceptsDtype("bar", row.dtype),
    )
    if (wrong) {
      return wrong.message
        ? `${wrong.message} is a ${wrong.dtype}; a bar draws numbers.`
        : "One of the rows is not bound to a message."
    }
    return null
  }

  // A media tile playing a camera's own stream binds no message: the browser
  // fetches it from the source, and the engine is not in the way of it.
  if (widget.type === "media" && text(cfg.stream_url) && !text(cfg.message)) {
    return null
  }

  const input = INPUT_WIDGETS.has(widget.type)
  const bound = text(cfg[input ? "target" : "message"])
  if (!bound) {
    return input
      ? "This control does not publish to a message yet."
      : "This widget is not bound to a message yet."
  }
  const dtype = cfg.dtype === undefined ? undefined : text(cfg.dtype)
  if (!acceptsDtype(widget.type, dtype)) {
    return `${bound} is a ${dtype}; a ${WIDGET_LABELS[widget.type].toLowerCase()} cannot carry that.`
  }
  if (widget.type === "color") {
    const want = COLOR_DTYPES[colorFormatOf(widget)]
    if (dtype && dtype !== want) {
      return `${bound} is a ${dtype}; this disc sends ${colorFormatOf(widget)}, which is a ${want}.`
    }
  }
  if (widget.type === "icon" && !(cfg.rules as unknown[] | undefined)?.length) {
    return "This icon has nothing mapped yet."
  }
  return null
}

function Unbound() {
  return <p className="text-muted-foreground">Pick a message.</p>
}

// ---------------------------------------------------------------------------
// Display
// ---------------------------------------------------------------------------

function StatWidget({ widget }: WidgetProps) {
  const { Readout } = useUi()
  const cfg = config(widget)
  const message = text(cfg.message)
  const live = useBoundValue(message || undefined)
  if (!message) return <Unbound />

  return (
    <Readout
      value={live?.value}
      precision={cfg.precision === undefined ? null : num(cfg.precision, 1)}
      unit={cfg.unit ? text(cfg.unit) : undefined}
    />
  )
}

/**
 * A dial, drawn as an arc.
 *
 * The number is always written out as well: a reading that only exists as an
 * angle is unreadable to anyone who cannot judge one.
 */
function GaugeWidget({ widget }: WidgetProps) {
  const { Gauge } = useUi()
  const cfg = config(widget)
  const message = text(cfg.message)
  const live = useBoundValue(message || undefined)
  if (!message) return <Unbound />

  return (
    <Gauge
      value={typeof live?.value === "number" ? live.value : null}
      min={num(cfg.min, 0)}
      max={num(cfg.max, 100)}
      precision={cfg.precision === undefined ? 1 : num(cfg.precision, 1)}
      unit={cfg.unit ? text(cfg.unit) : undefined}
      label={widget.title || message}
    />
  )
}

/**
 * A very small markdown subset, read a line at a time: headings and list items.
 * Inline spans — bold, code, links — are not parsed and read as written.
 *
 * Enough for the labels and notes a dashboard carries, and not worth a parser.
 */
function MarkdownWidget({ widget }: WidgetProps) {
  const content = text(config(widget).content)
  const lines = content.split("\n")
  return (
    <div className="grid gap-1 break-words">
      {lines.map((line, index) => {
        const heading = /^(#{1,3})\s+(.*)$/.exec(line)
        const body = heading ? heading[2] : line.replace(/^[-*]\s+/, "")
        const bullet = !heading && /^[-*]\s+/.test(line)
        return (
          <p
            // Plain text: position is the only identity a line has.
            key={`line-${index}`}
            className={cn(
              heading?.[1] === "#" && "font-medium",
              heading?.[1] === "##" && "font-medium",
              heading?.[1] === "###" && "text-muted-foreground",
              bullet && "pl-4",
            )}
            // Relative to the widget's own size, so an inline value rather
            // than an arbitrary Tailwind class.
            style={heading?.[1] === "#" ? { fontSize: "1.35em" } : undefined}
          >
            {bullet ? "• " : ""}
            {body}
          </p>
        )
      })}
    </div>
  )
}

/** One item of an agenda, as the `list` message declares it. */
type AgendaItem = { title: string; ts: number; all_day?: boolean }

const DAY_MS = 86_400_000

/**
 * Which day something falls on, said the way a person would.
 *
 * Today and tomorrow by name, the rest of the week by weekday, and anything
 * further out by date — past a week "Thursday" stops telling you which one.
 */
function dayLabel(when: Date, now: Date): string {
  const midnight = new Date(now).setHours(0, 0, 0, 0)
  const days = Math.floor(
    (new Date(when).setHours(0, 0, 0, 0) - midnight) / DAY_MS,
  )
  if (days === 0) return "Today"
  if (days === 1) return "Tomorrow"
  if (days < 7) return when.toLocaleDateString(undefined, { weekday: "long" })
  return when.toLocaleDateString()
}

/**
 * What is coming up, from a `list` of items the message declares.
 *
 * The shape is the widget's contract rather than a path per binding: every
 * item is `{title, ts}` with an optional `all_day`, so a flow answering with
 * a calendar decides what an entry is called and this only has to draw it.
 */
function AgendaWidget({ widget }: WidgetProps) {
  const cfg = config(widget)
  const message = text(cfg.message)
  const live = useBoundValue(message || undefined)
  if (!message) return <Unbound />

  const now = new Date()
  const today = new Date(now).setHours(0, 0, 0, 0) / 1000
  const items = (Array.isArray(live?.value) ? live.value : [])
    .filter(
      (item): item is AgendaItem =>
        typeof item?.title === "string" && Number.isFinite(item?.ts),
    )
    .filter((item) => item.ts >= today)
    .sort((a, b) => a.ts - b.ts)
    .slice(0, num(cfg.count, 5))

  if (items.length === 0) {
    return <p className="text-muted-foreground">Nothing coming up.</p>
  }

  return (
    // The frame centres a single reading in its card; a list reads from the
    // top, so it takes the slack below it.
    <ul className="mb-auto grid gap-1.5">
      {items.map((item, index) => {
        const when = new Date(item.ts * 1000)
        return (
          <li
            // Two entries can share a title and a time; position is the identity.
            key={`item-${index}`}
            className="flex min-w-0 items-baseline gap-2"
          >
            <span className="shrink-0 text-muted-foreground tabular-nums">
              {dayLabel(when, now)}
              {item.all_day
                ? ""
                : ` ${when.toLocaleTimeString(undefined, {
                    hour: "2-digit",
                    minute: "2-digit",
                  })}`}
            </span>
            <span className="truncate">{item.title}</span>
          </li>
        )
      })}
    </ul>
  )
}

/**
 * The last thing worth saying, held until something replaces it.
 *
 * No state of its own: the live store already keeps the latest value of a
 * message, so what was published stays on the panel until the next one lands.
 */
function NotificationWidget({ widget }: WidgetProps) {
  const cfg = config(widget)
  const message = text(cfg.message)
  const live = useBoundValue(message || undefined)
  if (!message) return <Unbound />

  const record = (live?.value ?? null) as Record<string, unknown> | null
  const title = text(record?.title)
  const body = text(record?.body)
  if (!title && !body) {
    return <p className="text-muted-foreground">Nothing to report.</p>
  }

  const failed = record?.severity === "error"
  return (
    <div className="grid gap-1 break-words">
      {title ? (
        <p
          className={cn(
            "flex items-baseline gap-1.5 font-medium",
            failed && "text-destructive",
          )}
        >
          {/* Never colour alone: a notice that went wrong says so in a word as
              well as in red. */}
          {failed ? <span className="sr-only">Error: </span> : null}
          {failed ? <span aria-hidden>⚠</span> : null}
          {title}
        </p>
      ) : null}
      {body ? <p className="text-muted-foreground">{body}</p> : null}
    </div>
  )
}

// ---------------------------------------------------------------------------
// Input
// ---------------------------------------------------------------------------

function ButtonWidget({ widget, dashboard }: WidgetProps) {
  const { Button } = useUi()
  const cfg = config(widget)
  const { target, send, pending, pulse, locked } = usePublish(widget, dashboard)
  if (!target) return <Unbound />
  // Nothing to hold: a button carries no reading, so the pulse and a refusal
  // are the whole of its feedback.
  return (
    <>
      {pulse}
      <Button
        variant="tonal"
        disabled={pending || locked}
        onClick={() => send(cfg.value ?? true)}
      >
        {text(cfg.label, widget.title || "Send")}
      </Button>
    </>
  )
}

/**
 * A bool, published and read back — a latch either way it is drawn.
 *
 * `style: "button"` is a control that stays in rather than a track; both name
 * the state in words, because a fill alone does not say what it means.
 */
function SwitchWidget({ widget, dashboard }: WidgetProps) {
  const { Button, Switch } = useUi()
  const cfg = config(widget)
  const { target, value, send, pulse, locked } = usePublish(widget, dashboard)
  if (!target) return <Unbound />

  const on = value === true
  return cfg.style === "button" ? (
    <>
      {pulse}
      <Button
        variant={on ? "filled" : "tonal"}
        pressed={on}
        label={widget.title || target}
        disabled={locked}
        onClick={() => send(!on)}
      >
        {on ? "On" : "Off"}
      </Button>
    </>
  ) : (
    <div className="flex items-center justify-between gap-2">
      {pulse}
      <span>{on ? "On" : "Off"}</span>
      <Switch
        checked={on}
        label={widget.title || target}
        disabled={locked}
        onChange={(checked) => send(checked)}
      />
    </div>
  )
}

function SliderWidget({ widget, dashboard }: WidgetProps) {
  const { Readout, Slider } = useUi()
  const cfg = config(widget)
  const { target, value, send, pulse, locked } = usePublish(widget, dashboard)
  const min = num(cfg.min, 0)
  if (!target) return <Unbound />

  const unit = cfg.unit ? text(cfg.unit) : undefined
  return (
    // Value beside the track rather than above it, the way a bar row reads —
    // one row instead of two, and the tile keeps the height for the control.
    <div className="flex items-start gap-3">
      {pulse}
      <div className="min-w-0 flex-1">
        <Slider
          value={typeof value === "number" ? value : min}
          min={min}
          max={num(cfg.max, 100)}
          step={num(cfg.step, 1)}
          unit={unit}
          // On by default, because a slider without them says how far along it
          // is and not what that means. Off is for a short tile: they are the
          // last row of a control that has three, and on a seven-inch panel
          // that row is the difference between fitting and being cut off.
          ticks={cfg.ticks !== false}
          label={widget.title || target}
          disabled={locked}
          onCommit={send}
        />
      </div>
      {/* Held to the control's own height, so the value sits on the track's
          midline whether or not there is a row of ticks under it. */}
      <div className="flex h-[var(--dui-control)] shrink-0 items-center">
        <Readout
          value={typeof value === "number" ? value : min}
          precision={null}
          unit={unit}
          size="inline"
        />
      </div>
    </div>
  )
}

function InputWidget({ widget, dashboard }: WidgetProps) {
  const { Input } = useUi()
  const cfg = config(widget)
  const { target, value, send, pulse, locked } = usePublish(widget, dashboard)
  const [draft, setDraft] = useState<string | null>(null)
  if (!target) return <Unbound />

  const asNumber = cfg.dtype === "float" || cfg.dtype === "int"
  return (
    <>
      {pulse}
      <Input
        value={draft ?? text(value)}
        type={asNumber ? "number" : "text"}
        label={widget.title || target}
        disabled={locked}
        onChange={setDraft}
        onCommit={() => {
          if (draft === null) return
          send(asNumber ? Number(draft) || 0 : draft)
          setDraft(null)
        }}
      />
    </>
  )
}

/**
 * One of N, published and read back.
 *
 * `style: "segmented"` shows every choice at once with the active one held —
 * the same exclusive group, drawn for a panel that is looked at across a room.
 */
function DropdownWidget({ widget, dashboard }: WidgetProps) {
  const { Segmented, Select } = useUi()
  const cfg = config(widget)
  const { target, value, send, pulse, locked } = usePublish(widget, dashboard)
  const options = (cfg.options ?? []) as { label?: string; value?: unknown }[]
  if (!target) return <Unbound />

  if (cfg.style === "segmented") {
    return (
      <>
        {pulse}
        <Segmented
          value={text(value)}
          options={options.map(
            (option) =>
              [text(option.value), option.label ?? text(option.value)] as const,
          )}
          label={widget.title || target}
          disabled={locked}
          onChange={(picked) =>
            send(options.find((o) => text(o.value) === picked)?.value ?? picked)
          }
        />
      </>
    )
  }

  return (
    <>
      {pulse}
      <Select
        value={text(value)}
        options={options}
        label={widget.title || target}
        disabled={locked}
        onChange={send}
      />
    </>
  )
}

// ---------------------------------------------------------------------------

export type WidgetProps = { widget: WidgetDef; dashboard: string }

const RENDERERS: Partial<
  Record<WidgetKind, (props: WidgetProps) => React.ReactNode>
> = {
  stat: StatWidget,
  gauge: GaugeWidget,
  chart: ChartWidget,
  markdown: MarkdownWidget,
  agenda: AgendaWidget,
  notification: NotificationWidget,
  bar: BarWidget,
  icon: IconWidget,
  forecast: ForecastWidget,
  clock: ClockWidget,
  media: MediaWidget,
  button: ButtonWidget,
  switch: SwitchWidget,
  slider: SliderWidget,
  input: InputWidget,
  dropdown: DropdownWidget,
  color: ColorWidget,
}

export function WidgetBody({ widget, dashboard }: WidgetProps) {
  const Renderer = RENDERERS[widget.type]
  if (!Renderer) {
    return (
      <p className="text-muted-foreground">
        {WIDGET_LABELS[widget.type]} widgets are not drawn yet.
      </p>
    )
  }
  return <Renderer widget={widget} dashboard={dashboard} />
}