import type {
  InterfaceRevision,
  PackageRevision,
  ValueType,
  DependencyPort,
  WorkspaceRevision,
} from "../capability-model/types.js";
import type { CompiledCapabilityResourceRepository } from "../capability-language/assembly.js";
import { genericImplementationType } from "./generics.js";
import { capabilityId } from "../capability-model/types.js";

/** Portable generator input. New backends consume this instead of the parser or TS runtime. */
export type BindingSchema = {
  format: "quixos-bindings";
  version: 1;
  interfaces: InterfaceRevision[];
  interfaceTemplates?: InterfaceRevision[];
  packages: PackageRevision[];
};
export const bindingSchema = (compiled: Pick<CompiledCapabilityResourceRepository, "resources">): BindingSchema => ({
  format: "quixos-bindings",
  version: 1,
  interfaceTemplates: compiled.resources.flatMap((node) =>
    node.resource.kind === "interface" && node.resource.revision.template ? [node.resource.revision] : [],
  ),
  interfaces: [
    ...new Map(
      compiled.resources
        .flatMap((node) => [
          ...(node.resource.kind === "interface" ? [node.resource.revision] : []),
          ...(node.resource.specializations ?? []),
        ])
        .filter((entry) => !entry.template)
        .map((entry) => [entry.revisionId, entry]),
    ).values(),
  ],
  packages: compiled.resources.flatMap((node) => (node.resource.kind === "package" ? [node.resource.revision] : [])),
});

export const specializeBindingSchema = (
  base: BindingSchema,
  workspace: WorkspaceRevision,
  revisionId: string,
): BindingSchema => {
  const pkg = workspace.packageImports.find((entry) => entry.revisionId === revisionId);
  if (!pkg) throw new Error(`Missing candidate package ${revisionId}`);
  const needed = new Set<string>();
  const visit = (value: unknown): void => {
    if (!value || typeof value !== "object") return;
    if ("interfaceRevisionId" in value && typeof value.interfaceRevisionId === "string")
      needed.add(value.interfaceRevisionId);
    Object.values(value).forEach(visit);
  };
  visit(pkg.exports);
  const interfaces = new Map<string, InterfaceRevision>(base.interfaces.map((entry) => [entry.revisionId, entry]));
  for (const id of needed) {
    const iface = workspace.interfaceImports.find((entry) => entry.revisionId === id);
    if (iface) {
      interfaces.set(id, iface);
      visit(iface.members);
    }
  }
  return {
    ...base,
    interfaces: [...interfaces.values()],
    packages: base.packages.map((entry) => {
      const candidate = workspace.packageImports.find((value) => value.revisionId === entry.revisionId);
      if (!candidate) throw new Error(`Missing dependency package ${entry.revisionId}`);
      return candidate;
    }),
  };
};
export type TypeScriptBindingOptions = {
  runtimeModule?: string;
  /** Each export must implement MessageBinding<T>, providing both TS type and wire codec. */
  messages?: Record<string, { module: string; export: string }>;
};
export function generatePackageDescriptor(schema: BindingSchema, revisionId: string): string {
  const pkg = schema.packages.find((entry) => entry.revisionId === revisionId);
  if (!pkg) throw new Error(`Unknown package revision ${revisionId}`);
  return (
    `# Generated from the checked package contract\npackage_id: ${JSON.stringify(pkg.packageId)}\npackage_revision_id: ${JSON.stringify(pkg.revisionId)}\nruntime_protocol_version: "quixos-capabilities-v1"\n` +
    pkg.exports
      .map(
        (entry) =>
          `exports: { export_id: ${JSON.stringify(entry.id)} runtime_symbol: ${JSON.stringify(entry.displayName)} }\n`,
      )
      .join("")
  );
}
const q = JSON.stringify;
const object = (entries: [string, string][]) =>
  `{ ${entries.map(([key, value]) => `${q(key)}: ${value}`).join("; ")} }`;
const unit = (type: ValueType) => type.kind === "builtin" && type.name === "unit";

export const generateTypeScriptBindings = (
  schema: BindingSchema,
  packageRevisionId: string,
  options: TypeScriptBindingOptions = {},
) => {
  if (schema.format !== "quixos-bindings" || schema.version !== 1)
    throw new Error("Unsupported binding schema version");
  if (schema.interfaces.some((entry) => entry.template))
    throw new Error("Package bindings require closed interface applications, not generic definitions");
  const pkg = schema.packages.find((entry) => entry.revisionId === packageRevisionId);
  if (!pkg) throw new Error(`Unknown package revision ${packageRevisionId}`);
  const messages = new Map<string, string>();
  const type = (value: ValueType): string => {
    switch (value.kind) {
      case "builtin":
        return value.name === "unit" ? "null" : "QxWatchHandle";
      case "scalar":
        return {
          bool: "boolean",
          bytes: "Uint8Array",
          string: "string",
          int64: "bigint",
          uint64: "bigint",
          double: "number",
          int32: "number",
          uint32: "number",
        }[value.name];
      case "object-ref":
        return `QxObjectRef<${q(value.expectation.kind === "atom" ? `atom:${value.expectation.atomId}` : `interface:${value.expectation.interfaceRevisionId}`)}>`;
      case "optional":
        return `(${type(value.value)} | null)`;
      case "list":
        return `Array<${type(value.value)}>`;
      case "record":
        return `{ ${Object.entries(value.fields)
          .map(([name, field]) => `${q(name)}: ${type(field)}`)
          .join("; ")} }`;
      case "message": {
        if (!options.messages?.[value.descriptorId])
          throw new Error(`Missing TypeScript message binding for ${value.descriptorId}`);
        if (!messages.has(value.descriptorId)) messages.set(value.descriptorId, `message${messages.size}`);
        return `BindingValue<typeof ${messages.get(value.descriptorId)}>`;
      }
    }
  };
  const ref = (target: { kind: "atom"; atomId: string } | { kind: "interface"; interfaceRevisionId: string }) =>
    `QxObjectRef<${q(target.kind === "atom" ? `atom:${target.atomId}` : `interface:${target.interfaceRevisionId}`)}>`;
  const params = (input: ValueType) => (unit(input) ? "" : `input: ${type(input)}`);
  const port = (entry: DependencyPort): { type: string; spec: unknown } => {
    const requirement = entry.requirement;
    switch (requirement.kind) {
      case "state": {
        const methods = requirement.primitives.map((primitive): [string, string] => {
          if (primitive === "read") return ["get", `() => Promise<${type(requirement.valueType)}>`];
          if (primitive === "write") return ["set", `(value: ${type(requirement.valueType)}) => Promise<void>`];
          throw new Error(`State primitive ${primitive} is not supported by the TypeScript runtime binding yet`);
        });
        if (requirement.primitives.includes("read")) methods.push(["live", "() => Promise<QxLiveValue>"]);
        return { type: object(methods), spec: { ...requirement, id: entry.id } };
      }
      case "edge": {
        const methods = requirement.primitives.map((primitive): [string, string] => {
          if (primitive === "resolve") return [primitive, `() => Promise<Array<${ref(requirement.target)}>>`];
          if (primitive === "connect" || primitive === "disconnect")
            return [primitive, `(target: ${ref(requirement.target)}) => Promise<void>`];
          throw new Error(`Edge primitive ${primitive} is not supported by the TypeScript runtime binding yet`);
        });
        if (requirement.primitives.includes("resolve"))
          methods.push(["collection", `() => Promise<RelationshipCollection<${ref(requirement.target)}>>`]);
        if (
          ["resolve", "connect", "disconnect"].every((primitive) =>
            requirement.primitives.includes(primitive as "resolve"),
          )
        )
          methods.push([
            "replace",
            `(entries: RelationshipEntry<${ref(requirement.target)}>[], expectedRevision: bigint) => Promise<RelationshipCollection<${ref(requirement.target)}>>`,
          ]);
        return { type: object(methods), spec: { kind: "edge", id: entry.id, primitives: requirement.primitives } };
      }
      case "interface": {
        const contract = schema.interfaces.find(
          (candidate) => candidate.revisionId === requirement.interfaceRevisionId,
        );
        if (!contract) throw new Error(`Missing imported interface contract ${requirement.interfaceRevisionId}`);
        // Streaming ports need a future streaming ABI; ordinary calls are fully typed today.
        const operations = contract.members.flatMap((member) =>
          member.operations
            .filter((operation) => operation.mode === "call" && operation.scope !== "class")
            .map((operation) => ({ ...operation, name: `${member.displayName}.${operation.displayName}` })),
        );
        const methods: [string, string][] = [
          ["objectId", ref({ kind: "interface", interfaceRevisionId: requirement.interfaceRevisionId })],
          [
            "live",
            object(
              operations.map((operation) => [
                operation.name,
                `(${params(operation.inputType)}) => Promise<QxLiveValue>`,
              ]),
            ),
          ],
          ...operations.map((operation): [string, string] => [
            operation.name,
            `(${params(operation.inputType)}) => Promise<${type(operation.outputType)}>`,
          ]),
        ];
        return {
          type: object([...methods, ["contract", `QxInterfaceContract<${object(methods)}>`]]),
          spec: {
            kind: "interface",
            id: entry.id,
            interfaceRevisionId: requirement.interfaceRevisionId,
            operations: Object.fromEntries(
              operations.map(({ name, id, inputType, outputType }) => [name, { id, inputType, outputType }]),
            ),
          },
        };
      }
      case "constructor": {
        const input = requirement.inputType;
        if (!input)
          throw new Error(
            `Constructor port ${entry.id} needs an explicit input contract: add 'input TYPE' after ${requirement.atomId} in QX`,
          );
        return {
          type: object([
            ["construct", `(${params(input)}) => Promise<${ref({ kind: "atom", atomId: requirement.atomId })}>`],
          ]),
          spec: { kind: "constructor", id: entry.id, inputType: input },
        };
      }
    }
  };
  const exports = [...pkg.exports].sort((a, b) => (a.id < b.id ? -1 : a.id > b.id ? 1 : 0));
  const names = new Set<string>();
  const specs: Record<string, unknown> = {};
  const contexts: [string, string][] = [];
  const handlers: [string, string][] = [];
  const results: [string, string][] = [];
  for (const entry of exports) {
    if (names.has(entry.displayName)) throw new Error(`Duplicate export name ${entry.displayName}`);
    names.add(entry.displayName);
    const ports = entry.dependencyPorts.map((dependency) => ({ name: dependency.displayName, ...port(dependency) }));
    if (new Set(ports.map((p) => p.name)).size !== ports.length)
      throw new Error(`Duplicate dependency name in ${entry.displayName}`);
    const receiver =
      entry.kind === "constructor"
        ? ref({ kind: "atom", atomId: entry.constructsAtom })
        : entry.kind === "operation" && entry.receiverRequirement.kind === "exact-atom"
          ? ref({ kind: "atom", atomId: entry.receiverRequirement.atomId })
          : entry.kind === "operation" && entry.receiverRequirement.kind === "all-interfaces"
            ? `QxObjectRef<${entry.receiverRequirement.interfaceRevisionIds.map((id) => q(`interface:${id}`)).join(" | ") || "never"}>`
            : "QxObjectRef<string>";
    const contextShape = object([
      ["conform", "QxConformer"],
      ...(entry.kind === "function" ? [] : [["objectId", receiver] as [string, string]]),
      ["input", type(entry.inputType)],
      ["ports", object(ports.map((port) => [port.name, port.type]))],
    ]);
    contexts.push([
      entry.displayName,
      entry.kind === "function"
        ? `${contextShape} & {signal?: AbortSignal}`
        : `${contextShape} & QxContextLifecycle<${contextShape} & {signal?: AbortSignal}>`,
    ]);
    const event = entry.kind === "operation" ? entry.eventType : undefined;
    const contextType = `Contexts[${q(entry.displayName)}]`;
    const outputType = type(event ?? entry.outputType);
    results.push([entry.displayName, outputType]);
    // Watch-start handlers produce events through the runtime's derived stream protocol.
    if (!entry.application)
      handlers.push([
        entry.displayName,
        event
          ? `QxDerived<${contextType}, ${outputType}>`
          : `QxHandler<${contextType}, ${outputType}>${entry.kind === "operation" && entry.mode === "call" ? ` | QxDerived<${contextType}, ${outputType}>` : ""}`,
      ]);
    specs[entry.displayName] = {
      ...(entry.kind === "function" ? { receiver: "none" } : {}),
      inputType: entry.inputType,
      outputType: entry.outputType,
      ...(event ? { eventType: event } : {}),
      ports: Object.fromEntries(ports.map((port) => [port.name, port.spec])),
    };
  }
  for (const definition of pkg.genericExports ?? []) {
    handlers.push([
      definition.displayName,
      genericImplementationType(definition, [...schema.interfaces, ...(schema.interfaceTemplates ?? [])], type),
    ]);
  }
  // Unused imported interfaces must not introduce new message-codec obligations.
  // A used port still fails above if its own required codec is missing.
  const hasCodec = (value: ValueType): boolean => {
    if (value.kind === "message") return !!options.messages?.[value.descriptorId];
    if (value.kind === "record") return Object.values(value.fields).every(hasCodec);
    if (value.kind === "list" || value.kind === "optional") return hasCodec(value.value);
    return true;
  };
  const contracts = schema.interfaces
    .filter((iface) =>
      iface.members.every((member) =>
        member.operations
          .filter((operation) => operation.mode === "call" && operation.scope !== "class")
          .every((operation) => hasCodec(operation.inputType) && hasCodec(operation.outputType)),
      ),
    )
    .map((iface) => {
      const generated = port({
        id: capabilityId.dependencyPort("contract"),
        displayName: iface.displayName,
        requirement: { kind: "interface", interfaceRevisionId: iface.revisionId },
      });
      const spec = generated.spec as { operations: unknown };
      return {
        iface,
        type: generated.type,
        code: `defineQxInterfaceContract<${generated.type}>(${q(iface.revisionId)}, ${JSON.stringify(spec.operations)})`,
      };
    });
  const imports = [...messages].map(([id, alias]) => {
    const binding = options.messages![id]!;
    if (!/^[A-Za-z_$][A-Za-z0-9_$]*$/.test(binding.export))
      throw new Error(`Invalid message binding export ${binding.export}`);
    return `import { ${binding.export} as ${alias} } from ${q(binding.module)};`;
  });
  const signatures = `${object(contexts)} ${object(handlers)} ${object(results)} ${contracts.map((entry) => entry.type).join(" ")}`;
  const typeImports = [
    "BindingValue",
    "QxObjectRef",
    "QxWatchHandle",
    "QxHandler",
    "QxDerived",
    "QxContextLifecycle",
    "QxConformer",
    "QxInterfaceContract",
    "QxLiveValue",
    "RelationshipCollection",
    "RelationshipEntry",
  ].filter((name) => new RegExp(`\\b${name}\\b`).test(signatures));
  return (
    `// Generated by quixos-codegen-ts. Do not edit. Binding ABI version 1.\n` +
    `import { ${contracts.length ? "defineQxInterfaceContract, " : ""}${exports.length ? "bindQxHandler, " : ""}${[...typeImports, "QxHandlerSpec", "QxMessages"].map((name) => `type ${name}`).join(", ")} } from ${q(options.runtimeModule ?? "@quixos/camino-package-runtime")};\n` +
    imports.join("\n") +
    `\nexport const packageRevisionId = ${q(pkg.revisionId)};\n` +
    `declare const appliedType: unique symbol;\ntype QxApplied<Definition extends string, Arguments extends readonly unknown[]> = string & {readonly [appliedType]: (value: [Definition, Arguments]) => [Definition, Arguments]};\n` +
    `export type Contexts = ${object(contexts)};\nexport type Results = ${object(results)};\nexport type Implementation = ${object(handlers)};\n` +
    `export const contracts = {${contracts.map((entry) => `${q(entry.iface.revisionId)}: ${entry.code}`).join(",\n")}};\n` +
    `export const interfaces = {${contracts
      .filter((entry) => contracts.filter((other) => other.iface.displayName === entry.iface.displayName).length === 1)
      .map((entry) => `${q(entry.iface.displayName)}: contracts[${q(entry.iface.revisionId)}]`)
      .join(",\n")}};\n` +
    `const messages = { ${[...messages].map(([id, alias]) => `${q(id)}: ${alias}`).join(", ")} } satisfies QxMessages;\n` +
    `const specs = ${JSON.stringify(specs, null, 2)} satisfies Record<string, QxHandlerSpec>;\n` +
    `export const createRuntime = (implementation: Implementation) => ({\n  packageRevisionId,\n  exports: {\n` +
    exports
      .map(
        (entry) =>
          `    ${q(entry.id)}: bindQxHandler(specs[${q(entry.displayName)}], implementation[${q(entry.application ? pkg.genericExports!.find((definition) => definition.id === entry.application!.exportId)!.displayName : entry.displayName)}], messages),`,
      )
      .join("\n") +
    `\n  },\n});\n`
  );
};