import type {
  BoundDependency,
  Conformance,
  DependencyPort,
  InitializationField,
  ValueType,
  WorkspaceRevision,
} from "./types.js";
import type { CapabilityValidationIssue } from "./validation.js";
import { cardinalityValueType, valueTypesEqual } from "./validation.js";

/** Creation grants seed inputs on new objects, never general private-state authority. */
export function validateInitialization(workspace: WorkspaceRevision): CapabilityValidationIssue[] {
  const issues: CapabilityValidationIssue[] = [];
  const fail = (path: string, message: string) => issues.push({ code: "invalid-initialization", path, message });
  const ownerKey = (owner: Conformance) => `${owner.atomId}/${owner.interfaceRevisionId}`;
  const shapes = new Map<string, ValueType>();
  const fieldType = (owner: Conformance, field: InitializationField): ValueType | undefined => {
    const binding = field.binding;
    const attachment = owner.privateAttachments.find(
      (a) => a.kind === binding.kind && a.id === (binding.kind === "state" ? binding.slotId : binding.edgeTypeId),
    );
    if (!attachment) {
      fail(ownerKey(owner), `Initialization input ${field.input} must name an attachment owned by this conformance`);
      return;
    }
    if (attachment.kind === "state") return attachment.valueType;
    if (binding.kind !== "edge") return;
    const index = attachment.endpoints.findIndex((e) => e.projectionId === binding.projectionId);
    const endpoint = attachment.endpoints[index];
    const target = attachment.endpoints[1 - index];
    if (!endpoint || !target || endpoint.constraint.kind !== "atom" || endpoint.constraint.atomId !== owner.atomId) {
      fail(ownerKey(owner), `Initialization input ${field.input} must name an edge projection on the newborn atom`);
      return;
    }
    if (target.keyType) {
      fail(
        ownerKey(owner),
        "Initialize a keyed relationship through its keyed projection; inverse seeds cannot supply a map key",
      );
      return;
    }
    if (endpoint.cardinality === "many" || endpoint.cardinality === "many-unique") {
      const fields: Record<string, ValueType> = {
        key: { kind: "scalar", name: "string" },
        target: cardinalityValueType(target.constraint, "exactly-one"),
      };
      if (endpoint.keyType)
        fields.mapKey = { kind: "scalar", name: endpoint.keyType === "boolean" ? "bool" : endpoint.keyType };
      return { kind: "list", value: { kind: "record", fields } };
    }
    return cardinalityValueType(target.constraint, endpoint.cardinality);
  };
  for (const owner of workspace.conformances) {
    if (!owner.initialization) continue;
    const fields: Record<string, ValueType> = Object.create(null);
    const destinations = new Set<string>();
    for (const field of owner.initialization) {
      const path = `${ownerKey(owner)}/${field.input}`;
      if (!field.input || Object.hasOwn(fields, field.input))
        fail(path, "Initialization input names must be nonempty and distinct");
      const destination = JSON.stringify(field.binding);
      if (destinations.has(destination)) fail(path, "An attachment may have only one initialization input");
      destinations.add(destination);
      const type = fieldType(owner, field);
      if (type) fields[field.input] = type;
    }
    shapes.set(ownerKey(owner), { kind: "record", fields });
  }
  const checkBindings = (ports: DependencyPort[], dependencies: BoundDependency[], path: string) => {
    for (const dependency of dependencies) {
      if (dependency.binding.kind !== "creation") continue;
      const binding = dependency.binding;
      const requirement = ports.find((p) => p.id === dependency.portId)?.requirement;
      if (requirement?.kind !== "creation") continue; // General binding validation reports the kind mismatch.
      const portPath = `${path}/${dependency.portId}`;
      if (binding.atomId !== requirement.atomId) fail(portPath, `Creation port requires atom ${requirement.atomId}`);
      const initialized = new Set<string>();
      const supplied = new Set<string>();
      for (const mapping of binding.owners) {
        const key = `${binding.atomId}/${mapping.interfaceRevisionId}`;
        if (supplied.has(key)) fail(portPath, `Duplicate initialization owner ${key}`);
        supplied.add(key);
        const owner = workspace.conformances.find((o) => ownerKey(o) === key);
        const shape = shapes.get(key);
        if (!owner || !shape) {
          fail(portPath, `Owner ${key} has no declared initialization mapping`);
          continue;
        }
        let seed: ValueType | undefined = requirement.inputType;
        for (const component of mapping.inputPath) seed = seed?.kind === "record" ? seed.fields[component] : undefined;
        if (!seed || !valueTypesEqual(seed, shape))
          fail(
            portPath,
            `Seed input${mapping.inputPath.map((p) => `.${p}`).join("")} does not match initialization inputs of ${key}`,
          );
        for (const field of owner.initialization!)
          if (field.binding.kind === "state") initialized.add(field.binding.slotId);
      }
      const states = [
        ...workspace.sharedAttachments,
        ...workspace.conformances.flatMap((o) => o.privateAttachments),
      ].filter((a) => a.kind === "state" && a.attachedTo === binding.atomId);
      for (const state of states)
        if (state.kind === "state" && state.defaultValue === undefined && !initialized.has(state.id))
          fail(portPath, `Required state ${state.id} has no default or declared seed mapping`);
    }
  };
  const exports = new Map(
    workspace.packageImports.flatMap((p) => p.exports.map((e) => [`${p.revisionId}/${e.id}`, e] as const)),
  );
  for (const owner of workspace.conformances)
    for (const operation of owner.operationBindings) {
      if (operation.binding.kind !== "package") continue;
      const entry = exports.get(`${operation.binding.packageRevisionId}/${operation.binding.exportId}`);
      if (entry)
        checkBindings(
          entry.dependencyPorts,
          operation.binding.dependencies,
          `${ownerKey(owner)}/${operation.operationId}`,
        );
    }
  for (const constructor of workspace.constructors) {
    const entry = exports.get(`${constructor.packageRevisionId}/${constructor.exportId}`);
    if (entry) checkBindings(entry.dependencyPorts, constructor.dependencies, `constructor/${constructor.atomId}`);
  }
  return issues;
}