import { createContext, useContext } from "react"

import type { DashboardDef_Output, SettingDef } from "@/client"
import { NO_PALETTE } from "@/components/Common/UplotChart"
import { useLiveValue } from "@/components/Flow/liveStore"
import { isLight, parsePalette, rolesOf } from "./ui/core/theme"

/**
 * The dashboard's own settings channel.
 *
 * A widget is a receiver a dashboard *contains*; this is the dashboard itself
 * as one. Each setting is a value plus an optional binding:
 *
 * - **Unbound** — no message — the setting is simply its value. That is what
 *   gives a wall panel which is always dark without a flow behind it.
 * - **Bound** — a flow drives it live, and the stored value is the fallback:
 *   what the dashboard uses until something arrives, and whenever the message
 *   is silent.
 *
 * A schedule is not a third case. A node publishing to the bound message on a
 * cron *is* the schedule here, which is the whole reason this is a channel
 * rather than a switching rule bolted onto each setting.
 *
 * A bound setting is read the way a widget reads a value — the same live store
 * and the same socket — so a panel's own settings messages are part of what
 * its credential is entitled to (`flow/panels.py`, `messages_for`).
 */

/**
 * What a setting may be driven by, by payload type. The same table is enforced
 * on the server (`app/flow/dashboards.py`); a name missing from it is a
 * setting this build does not act on rather than an error.
 */
export const SETTING_DTYPES = {
  theme: "str",
  locked: "bool",
  /** `fluksio`, `material` or `glass`; anything else is `fluksio`. */
  look: "str",
  /** Hex colours, roles by position — see `ui/core/theme.ts`. */
  palette: "list",
  /** The URL of an image drawn under the widgets. */
  background: "str",
  /** Bigger controls, for a panel that is touched rather than pointed at. */
  touch: "bool",
} as const satisfies Record<string, string>

/** The settings this build actually wires up. */
export type SettingName = keyof typeof SETTING_DTYPES

/** What `theme` may be set to. `system` follows whatever the device says. */
export const THEME_CHOICES = [
  ["system", "System"],
  ["light", "Light"],
  ["dark", "Dark"],
] as const

/** The generated client marks the map optional, because the server fills it in. */
export function settingOf(
  dashboard: DashboardDef_Output | undefined,
  name: SettingName,
): SettingDef {
  return dashboard?.settings?.[name] ?? {}
}

/**
 * What is wrong with a setting's binding, if anything.
 *
 * Judged from the document alone — the picker records the payload type beside
 * the name — so this is the same rule `widgetIssue` holds a tile to, and the
 * editor cannot author a document the server would refuse.
 */
export function settingIssue(name: string, setting: SettingDef): string | null {
  const want = SETTING_DTYPES[name as SettingName] as string | undefined
  if (!want || !setting.message || !setting.dtype) return null
  if (setting.dtype === want) return null
  return `${setting.message} is a ${setting.dtype}; ${name} is driven by a ${want}.`
}

/** What the setting is worth now: live if it is bound, stored otherwise. */
export function useSetting(
  dashboard: DashboardDef_Output | undefined,
  name: SettingName,
): unknown {
  const setting = settingOf(dashboard, name)
  // `undefined` while nothing has arrived, which is exactly when the stored
  // value is meant to stand in.
  const live = useLiveValue(setting.message || undefined)
  return live?.value ?? setting.value
}

/** What a dashboard is drawn as. Anything unrecorded wears the app's own. */
export type Look = "fluksio" | "glass" | "material"

/** The looks, as the editor offers them. The dashboard's own comes first. */
export const LOOK_CHOICES = [
  ["fluksio", "Fluksio"],
  ["material", "Material"],
  ["glass", "Glass"],
] as const

export const lookOf = (value: unknown): Look =>
  value === "glass" ? "glass" : value === "material" ? "material" : "fluksio"

/** Which of the two component sets draws this dashboard. */
export const useDashboardLook = (
  dashboard: DashboardDef_Output | undefined,
): Look => lookOf(useSetting(dashboard, "look"))

/** The dashboard's own colours, as the hexes a palette named. */
export const useDashboardPalette = (
  dashboard: DashboardDef_Output | undefined,
): string[] => parsePalette(useSetting(dashboard, "palette"))

/** An image drawn under the widgets, or `""` for the look's own ground. */
export function useDashboardBackground(
  dashboard: DashboardDef_Output | undefined,
): string {
  const value = useSetting(dashboard, "background")
  return typeof value === "string" ? value.trim() : ""
}

/** Whether this dashboard is drawn for a finger rather than a pointer. */
export const useDashboardTouch = (
  dashboard: DashboardDef_Output | undefined,
): boolean => useSetting(dashboard, "touch") === true

/**
 * The class that themes a dashboard's own surface, or `""` to follow the app.
 *
 * A class rather than the root, because inside the app shell this must not
 * flip the chrome around it. `.light` and `.dark` both redefine the tokens on
 * whatever carries them (`index.css`), so either direction works on a subtree.
 *
 * A palette decides this for itself: its first colour *is* the ground, so
 * whether the surface is light or dark is a fact about the palette rather than
 * a second setting that could disagree with it. The class still goes on,
 * because a chart canvas and the shadcn pieces inside the tile read it.
 */
export function useDashboardTheme(
  dashboard: DashboardDef_Output | undefined,
): "" | "light" | "dark" {
  const value = useSetting(dashboard, "theme")
  const roles = rolesOf(useDashboardPalette(dashboard))
  if (roles) return isLight(roles.background) ? "light" : "dark"
  return value === "dark" || value === "light" ? value : ""
}

/** Whether this dashboard is read-only, live if the setting is bound. */
export function useDashboardLocked(
  dashboard: DashboardDef_Output | undefined,
): boolean {
  return useSetting(dashboard, "locked") === true
}

const PaletteContext = createContext(NO_PALETTE)

/**
 * The data colours everything drawn under it uses.
 *
 * The colours a palette named, in draw order — the primary first, then the
 * accent, then whatever it listed after the roles. Empty when the dashboard
 * names no palette, which is not the same as "the ramp": a chart with no
 * palette spreads itself across the ramp by how many lines it draws
 * (`slotsFor`), and only a named palette overrides that.
 *
 * Mounted by the view *and* the editor: an editor drawing the automatic
 * spread while the panel beside it showed the dashboard's own palette would
 * be a preview that lies.
 *
 * Data colour only. A fault stays `--destructive` and a condition stays its
 * `ICON_COLORS` entry, because those name a state rather than tell one series
 * from another — a palette they followed could paint a failure the same blue
 * as a reading. Only the chart reads this today; a second consumer costs one
 * `usePalette()`.
 */
export function PaletteProvider({
  dashboard,
  children,
}: {
  dashboard: DashboardDef_Output | undefined
  children: React.ReactNode
}) {
  const palette = rolesOf(useDashboardPalette(dashboard))?.series ?? NO_PALETTE
  return (
    <PaletteContext.Provider value={palette}>
      {children}
    </PaletteContext.Provider>
  )
}

/** The ramp slots the dashboard around this widget named, or none. */
export const usePalette = () => useContext(PaletteContext)

const LockedContext = createContext(false)

/**
 * Marks everything drawn under it read-only.
 *
 * A context rather than a prop threaded through sixteen renderers: what a
 * control needs to know is one bit, and the one place it is acted on is
 * `usePublish`. Edit mode deliberately never mounts this — arranging a
 * dashboard is not the same as using it.
 */
export function LockedProvider({
  dashboard,
  children,
}: {
  dashboard: DashboardDef_Output | undefined
  children: React.ReactNode
}) {
  const locked = useDashboardLocked(dashboard)
  return (
    <LockedContext.Provider value={locked}>{children}</LockedContext.Provider>
  )
}

/** Whether the dashboard around this control is read-only. */
export const useLocked = () => useContext(LockedContext)