import type { UIEnvelope, UIEnvelopePayload, UIRegistry, UISurface } from "./types";

const surfaces = new Set<UISurface>(["chat_inline", "side_panel", "canvas", "map_overlay"]);

export function parseUiEnvelopePayload(value: unknown): UIEnvelopePayload | null {
  if (!isRecord(value)) {
    return null;
  }

  const envelope = parseUiEnvelope(value.envelope);
  if (!envelope) {
    return null;
  }

  return {
    session_id: typeof value.session_id === "string" ? value.session_id : "",
    envelope_id: typeof value.envelope_id === "string" ? value.envelope_id : "",
    created_at: typeof value.created_at === "number" ? value.created_at : Date.now(),
    envelope
  };
}

export function parseUiEnvelope(value: unknown): UIEnvelope | null {
  if (!isRecord(value) || value.schemaVersion !== "agent-ui@1") {
    return null;
  }

  if (value.kind === "registered_component") {
    if (typeof value.component !== "string" || !isSurface(value.surface)) {
      return null;
    }

    return {
      kind: "registered_component",
      schemaVersion: "agent-ui@1",
      component: value.component,
      surface: value.surface,
      props: value.props,
      data: value.data,
      fallbackText: optionalString(value.fallbackText)
    };
  }

  if (value.kind === "chart") {
    if (value.grammar !== "echarts-safe-subset" || !isChartSurface(value.surface)) {
      return null;
    }

    return {
      kind: "chart",
      schemaVersion: "agent-ui@1",
      grammar: "echarts-safe-subset",
      surface: value.surface,
      spec: value.spec,
      data: value.data,
      fallbackText: optionalString(value.fallbackText)
    };
  }

  if (value.kind === "map_action") {
    if (typeof value.action !== "string" || value.surface !== "map_overlay") {
      return null;
    }

    return {
      kind: "map_action",
      schemaVersion: "agent-ui@1",
      action: value.action,
      surface: "map_overlay",
      params: value.params,
      fallbackText: optionalString(value.fallbackText)
    };
  }

  return null;
}

export function isUiEnvelopeAllowed(envelope: UIEnvelope, registry: UIRegistry | null) {
  if (!registry) {
    return true;
  }

  if (envelope.kind === "registered_component") {
    const manifest = registry.components.find((item) => item.id === envelope.component);
    return Boolean(manifest?.supportedSurfaces.includes(envelope.surface));
  }

  if (envelope.kind === "chart") {
    return registry.chart_grammars.includes(envelope.grammar);
  }

  const manifest = registry.actions.find((item) => item.id === envelope.action);
  return Boolean(manifest?.supportedSurfaces.includes(envelope.surface));
}

export function parseUiRegistry(value: unknown): UIRegistry | null {
  if (!isRecord(value) || value.schema_version !== "agent-ui-registry@1") {
    return null;
  }

  return {
    schema_version: "agent-ui-registry@1",
    chart_grammars: stringArray(value.chart_grammars),
    components: manifestArray(value.components),
    actions: manifestArray(value.actions)
  };
}

function manifestArray(value: unknown) {
  if (!Array.isArray(value)) {
    return [];
  }

  return value.flatMap((item) => {
    if (!isRecord(item) || typeof item.id !== "string") {
      return [];
    }

    return [{ id: item.id, supportedSurfaces: stringArray(item.supportedSurfaces).filter(isSurface) }];
  });
}

function stringArray(value: unknown) {
  return Array.isArray(value) ? value.filter((item): item is string => typeof item === "string") : [];
}

function isChartSurface(value: unknown): value is "chat_inline" | "side_panel" | "canvas" {
  return value === "chat_inline" || value === "side_panel" || value === "canvas";
}

function isSurface(value: unknown): value is UISurface {
  return typeof value === "string" && surfaces.has(value as UISurface);
}

function optionalString(value: unknown) {
  return typeof value === "string" ? value : undefined;
}

function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === "object" && value !== null;
}