import type {
  ValueType,
  InitializationField,
  PersistentAttachment,
  DependencyBinding,
  BoundDependency,
  PackageExport,
} from "../capability-model/types.js";
import { type ExecutionPlan, ExecutionPlanError, hexDigest } from "./plan.js";
import { portableValueSchema } from "../bindings/portable.js";
function preparedInputPaths(type: ValueType, path: (string | null)[] = []): (string | null)[][] {
  if (type.kind === "change") return [path];
  if (type.kind === "optional") return preparedInputPaths(type.value, path);
  if (type.kind === "list") return preparedInputPaths(type.value, [...path, null]);
  if (type.kind === "record")
    return Object.entries(type.fields).flatMap(([key, value]) => preparedInputPaths(value, [...path, key]));
  return [];
}
/** Small data-only interpreter input; no compiler, parser, Node module or SQL dependency reaches the browser. */
export function compileKernelProgram(plan: ExecutionPlan): unknown {
  if (hexDigest(plan.definition) !== plan.digest)
    throw new ExecutionPlanError("INVALID_PLAN", "kernel", "Plan digest mismatch");
  const workspace = plan.definition.workspace;
  if (workspace.sharedAttachments.length)
    throw new ExecutionPlanError(
      "UNSUPPORTED_SHARED_STORAGE",
      "kernel",
      "Stage 0 requires explicit conformance-owned storage",
    );
  const schema = (type: ValueType): unknown | null => {
    try {
      return portableValueSchema(type);
    } catch {
      return null;
    }
  };
  const ownerBySlot = new Map<string, string>();
  const edges: unknown[] = [];
  const owners = plan.definition.owners.map((owner) => {
    const slots: unknown[] = [];
    for (const storage of owner.storage as PersistentAttachment[]) {
      if (storage.kind === "state") {
        const shape = schema(storage.valueType);
        if (!shape)
          throw new ExecutionPlanError("UNSUPPORTED_STORAGE_CODEC", storage.id, "Unsupported canonical value type");
        ownerBySlot.set(storage.id, owner.id);
        slots.push({
          id: storage.id,
          schema: shape,
          policy: storage.storagePolicy.kind === "register" ? "register" : "crdt",
          ...(Object.hasOwn(storage, "defaultValue") ? { defaultLiteral: storage.defaultValue } : {}),
        });
      } else {
        const endpoints = storage.endpoints.map((endpoint) => {
          if (endpoint.ordered || endpoint.keyType || endpoint.retainOther)
            throw new ExecutionPlanError(
              "UNSUPPORTED_GRAPH_FEATURE",
              storage.id,
              "Ordered/keyed relations and automatic retention are not implemented",
            );
          return {
            projection: endpoint.projectionId,
            constraint: {
              kind: endpoint.constraint.kind,
              id:
                endpoint.constraint.kind === "atom"
                  ? endpoint.constraint.atomId
                  : endpoint.constraint.interfaceRevisionId,
            },
            cardinality: endpoint.cardinality,
            ...(endpoint.onDelete ? { onDelete: endpoint.onDelete } : {}),
          };
        });
        edges.push({ id: storage.id, owner: owner.id, a: endpoints[0], b: endpoints[1] });
      }
    }
    return {
      id: owner.id,
      atom: owner.atom,
      interface: owner.interface,
      slots,
      initialize: (owner.initialization as InitializationField[]).map((field) => ({
        input: field.input,
        binding:
          field.binding.kind === "state"
            ? { kind: "state", slot: field.binding.slotId }
            : { kind: "edge", edge: field.binding.edgeTypeId, projection: field.binding.projectionId },
      })),
    };
  });
  const slotOwner = (slot: string) => {
    const owner = ownerBySlot.get(slot);
    if (!owner) throw new ExecutionPlanError("MISSING_STORAGE_OWNER", slot, "No checked owner");
    return owner;
  };
  const via = (binding: DependencyBinding) =>
    "via" in binding && binding.via
      ? { via: { edge: binding.via.edgeTypeId, projection: binding.via.projectionId } }
      : {};
  const operations = plan.definition.operations.map((operation) => {
    const binding = operation.binding;
    let target: unknown;
    let unsupported: string | null = null;
    if (binding.kind === "lifecycle") target = { kind: "lifecycle", primitive: binding.primitive };
    else if (binding.kind === "state")
      target = { kind: "state", owner: slotOwner(binding.slotId), slot: binding.slotId, primitive: binding.primitive };
    else if (binding.kind === "edge")
      target = {
        kind: "edge",
        edge: binding.edgeTypeId,
        projection: binding.projectionId,
        primitive: binding.primitive,
      };
    else {
      const pkg = workspace.packageImports.find((p) => p.revisionId === binding.packageRevisionId)!;
      const entry = pkg.exports.find((e) => e.id === binding.exportId)!;
      const compilePorts = (entry: PackageExport, dependencies: BoundDependency[]) =>
        dependencies.map((dependency) => {
          const requirement = entry.dependencyPorts.find((p) => p.id === dependency.portId)!.requirement;
          const bound = dependency.binding;
          const common = { id: dependency.portId, ...via(bound) };
          if (bound.kind === "state" && requirement.kind === "state")
            return {
              ...common,
              kind: "state",
              owner: slotOwner(bound.slotId),
              slot: bound.slotId,
              primitives: requirement.primitives,
            };
          if (bound.kind === "edge" && requirement.kind === "edge")
            return {
              ...common,
              kind: "edge",
              edge: bound.edgeTypeId,
              projection: bound.projectionId,
              primitives: requirement.primitives,
            };
          if (bound.kind === "interface" && requirement.kind === "interface") {
            const iface = workspace.interfaceImports.find((i) => i.revisionId === bound.interfaceRevisionId)!;
            return {
              ...common,
              kind: "interface",
              interface: bound.interfaceRevisionId,
              ...(bound.receiver ? { receiver: bound.receiver } : {}),
              operations: requirement.operations ?? iface.members.flatMap((m) => m.operations.map((o) => o.id)),
            };
          }
          if (bound.kind === "creation" && requirement.kind === "creation")
            return {
              ...common,
              kind: "creation",
              atom: bound.atomId,
              schema: portableValueSchema(requirement.inputType),
              recipe: hexDigest({ plan: plan.digest, operation: operation.key, port: dependency.portId }),
              owners: bound.owners.map((seed) => {
                const owner = owners.find((o) => o.atom === bound.atomId && o.interface === seed.interfaceRevisionId);
                if (!owner)
                  throw new ExecutionPlanError(
                    "MISSING_STORAGE_OWNER",
                    dependency.portId,
                    "Creation has no initialization owner",
                  );
                return { owner: owner.id, inputPath: seed.inputPath };
              }),
            };
          unsupported = `UNSUPPORTED_EXECUTION_PORT:${bound.kind}`;
          return { ...common, kind: "unavailable" };
        });
      const ports = compilePorts(entry, binding.dependencies);
      const check = entry.acceptanceExportId
        ? pkg.exports.find((candidate) => candidate.id === entry.acceptanceExportId)!
        : undefined;
      target = {
        kind: "package",
        package: binding.packageRevisionId,
        export: binding.exportId,
        ports,
        ...(check
          ? { acceptance: { export: check.id, ports: compilePorts(check, binding.acceptanceDependencies ?? []) } }
          : {}),
      };
    }
    const inputChanges = preparedInputPaths(operation.input);
    const input = schema(operation.input),
      output = schema(operation.output);
    return {
      key: operation.key,
      atom: operation.atomId,
      interface: operation.interfaceRevisionId,
      operation: operation.operationId,
      scope: operation.scope,
      effect: operation.execution.kind,
      targets: operation.execution.kind === "remote" ? [] : operation.execution.targets,
      input,
      ...(inputChanges.length ? { inputChanges } : {}),
      output,
      unsupported: unsupported ?? (input && output ? null : "UNSUPPORTED_OPERATION_CODEC"),
      binding: target,
    };
  });
  const packages = workspace.packageImports.map((pkg) => ({
    revision: pkg.revisionId,
    exports: pkg.exports.map((entry) => ({
      id: entry.id,
      ...(entry.acceptanceExportId ? { acceptance: entry.acceptanceExportId } : {}),
      effect: entry.execution?.kind ?? "remote",
      targets: entry.execution && entry.execution.kind !== "remote" ? entry.execution.targets : [],
      receiver:
        entry.kind === "function"
          ? null
          : entry.kind === "operation" && entry.receiverRequirement.kind === "exact-atom"
            ? { kind: "atom", id: entry.receiverRequirement.atomId }
            : "object",
      input: schema(entry.inputType),
      output: schema(entry.outputType),
    })),
  }));
  return {
    codec: "camino-kernel-program-v1",
    plan: plan.digest,
    model: { workspace: workspace.workspaceId, atoms: workspace.atoms.map((atom) => atom.id), owners, edges },
    operations,
    packages,
  };
}