import * as fs from "node:fs";
import * as path from "node:path";
import type { UastLanguage } from "./uast-runtime-receipt.js";

export type StructuralNodeKind = "ScopeNode" | "ControlNode" | "StateNode" | "LeafNode";
export type StructuralPatchDecision = "surgical" | "blocked";

export interface StructuralNodeCoordinate {
  file: string;
  language: UastLanguage;
  nodeKind: StructuralNodeKind;
  languageKind: string;
  path: number[];
  start: number;
  end: number;
  baseSha: string;
}

export interface StructuralPatchCheck {
  name: string;
  command: string;
  status: "pass" | "fail";
}

export interface StructuralPatchReceiptOptions {
  taskLabel: string;
  target: StructuralNodeCoordinate;
  parserReceipt?: string;
  serializerReceipt?: string;
  checks: StructuralPatchCheck[];
  rawStringPatch?: boolean;
  deployAttempted?: boolean;
  now?: Date;
}

export interface StructuralPatchReceipt {
  schema: "fable.structural_patch.receipt.v1";
  createdAt: string;
  taskLabel: string;
  target: StructuralNodeCoordinate;
  parserReceipt?: string;
  serializerReceipt?: string;
  checks: StructuralPatchCheck[];
  lockedSurroundingTree: boolean;
  decision: StructuralPatchDecision;
  reasons: string[];
  skipped: string[];
  deployAttempted: false;
}

function hasText(value: string | undefined): boolean {
  return Boolean(value?.trim());
}

export function createStructuralPatchReceipt(opts: StructuralPatchReceiptOptions): StructuralPatchReceipt {
  const reasons: string[] = [];
  if (!hasText(opts.taskLabel)) reasons.push("missing task label");
  if (!hasText(opts.target.file)) reasons.push("missing target file");
  if (!hasText(opts.target.languageKind)) reasons.push("missing language node kind");
  if (!hasText(opts.target.baseSha)) reasons.push("missing base sha");
  if (opts.target.path.length === 0) reasons.push("missing node path coordinates");
  if (opts.target.path.some((segment) => !Number.isInteger(segment) || segment < 0)) reasons.push("invalid node path coordinates");
  if (!Number.isInteger(opts.target.start) || !Number.isInteger(opts.target.end) || opts.target.start < 0 || opts.target.end <= opts.target.start) {
    reasons.push("invalid target span");
  }
  if (!hasText(opts.parserReceipt)) reasons.push("missing parser support receipt");
  if (!hasText(opts.serializerReceipt)) reasons.push("missing serializer support receipt");
  if (opts.checks.length === 0) reasons.push("missing validation checks");
  if (opts.checks.some((check) => !hasText(check.name) || !hasText(check.command))) reasons.push("validation checks need names and commands");
  if (opts.checks.some((check) => check.status !== "pass")) reasons.push("validation checks must pass");
  if (opts.rawStringPatch) reasons.push("raw string patch is not surgical");
  if (opts.deployAttempted) reasons.push("deploy is out of scope for structural patch receipts");

  return {
    schema: "fable.structural_patch.receipt.v1",
    createdAt: (opts.now ?? new Date()).toISOString(),
    taskLabel: opts.taskLabel,
    target: opts.target,
    parserReceipt: opts.parserReceipt,
    serializerReceipt: opts.serializerReceipt,
    checks: opts.checks,
    lockedSurroundingTree: reasons.length === 0,
    decision: reasons.length === 0 ? "surgical" : "blocked",
    reasons,
    skipped: ["raw string concatenation", "full universal UAST runtime", "cross-language pristine writer", "deploy"],
    deployAttempted: false,
  };
}

export function writeStructuralPatchReceipt(file: string, receipt: StructuralPatchReceipt): string {
  fs.mkdirSync(path.dirname(file), { recursive: true });
  fs.writeFileSync(file, `${JSON.stringify(receipt, null, 2)}\n`);
  return file;
}