import { createHash } from "node:crypto";

import { z } from "zod";

export type AttemptStatus = number | "NETWORK_REJECTION" | "PENDING_ABORT";
export type RetryReason = "NETWORK_FAILURE" | "HTTP_429" | "HTTP_503";
export type BodyDisposition =
  | "FULLY_READ_WITHIN_BOUND"
  | "CANCELLED_WITHOUT_READ"
  | "REJECTED_LIMIT"
  | "NO_RESPONSE";

const attemptStatusSchema = z.union([
  z.number().int().min(100).max(599),
  z.literal("NETWORK_REJECTION"),
  z.literal("PENDING_ABORT"),
]);

export const httpScenarioAssertionGroupsSchema = z
  .object({
    status: z
      .object({
        attempts: z.array(attemptStatusSchema).min(1),
        final: attemptStatusSchema,
      })
      .strict(),
    outcome: z.object({ kind: z.string().min(1), detail: z.string().nullable() }).strict(),
    effect: z.object({ outcome: z.string().min(1), observer: z.string().min(1) }).strict(),
    retry: z
      .object({
        count: z.number().int().nonnegative(),
        reasons: z.array(z.enum(["NETWORK_FAILURE", "HTTP_429", "HTTP_503"])),
      })
      .strict(),
    fetch: z
      .object({
        count: z.number().int().positive(),
        observerAttempts: z.number().int().positive(),
        agrees: z.boolean(),
      })
      .strict(),
    media: z.object({ attempts: z.array(z.string().nullable()).min(1), final: z.string().nullable() }).strict(),
    body: z
      .object({
        attempts: z
          .array(
            z
              .object({
                disposition: z.enum([
                  "FULLY_READ_WITHIN_BOUND",
                  "CANCELLED_WITHOUT_READ",
                  "REJECTED_LIMIT",
                  "NO_RESPONSE",
                ]),
                pulledBytes: z.number().int().nonnegative(),
                ceiling: z.number().int().nonnegative(),
              })
              .strict(),
          )
          .min(1),
      })
      .strict(),
    scope: z
      .object({
        start: z.literal("CURRENT"),
        end: z.enum(["CURRENT", "STALE"]),
        signal: z.enum(["ACTIVE", "ABORTED"]),
        cancellationOwner: z.enum(["NONE", "CALLER", "SCOPE_FENCE", "DEADLINE"]),
      })
      .strict(),
  })
  .strict()
  .superRefine((groups, context) => {
    const fail = (path: (string | number)[], message: string) => {
      context.addIssue({ code: "custom", path, message });
    };
    if (groups.status.final !== groups.status.attempts.at(-1)) {
      fail(["status", "final"], "must equal the final attempt status");
    }
    if (groups.retry.count !== groups.retry.reasons.length) {
      fail(["retry", "count"], "must equal retry reasons length");
    }
    if (groups.retry.count !== groups.fetch.count - 1) {
      fail(["retry", "count"], "must equal the non-final fetch attempt count");
    }
    for (const [index, reason] of groups.retry.reasons.entries()) {
      const status = groups.status.attempts[index];
      const expectedReason =
        status === "NETWORK_REJECTION"
          ? "NETWORK_FAILURE"
          : status === 429
            ? "HTTP_429"
            : status === 503
              ? "HTTP_503"
              : null;
      if (reason !== expectedReason) {
        fail(
          ["retry", "reasons", index],
          "must match the corresponding non-final attempt status",
        );
      }
    }
    if (groups.fetch.count !== groups.status.attempts.length) {
      fail(["fetch", "count"], "must equal status attempts length");
    }
    if (groups.fetch.count !== groups.media.attempts.length) {
      fail(["media", "attempts"], "must equal fetch count");
    }
    if (groups.fetch.count !== groups.body.attempts.length) {
      fail(["body", "attempts"], "must equal fetch count");
    }
    if (groups.fetch.observerAttempts !== groups.fetch.count) {
      fail(["fetch", "observerAttempts"], "must equal physical fetch count");
    }
    if (!groups.fetch.agrees) {
      fail(["fetch", "agrees"], "must prove physical/observer agreement");
    }
    if (groups.media.final !== groups.media.attempts.at(-1)) {
      fail(["media", "final"], "must equal the final attempt media essence");
    }
  });

export type HttpScenarioAssertionGroups = Readonly<{
  status: Readonly<{ attempts: readonly AttemptStatus[]; final: AttemptStatus }>;
  outcome: Readonly<{ kind: string; detail: string | null }>;
  effect: Readonly<{ outcome: string; observer: string }>;
  retry: Readonly<{ count: number; reasons: readonly RetryReason[] }>;
  fetch: Readonly<{
    count: number;
    observerAttempts: number;
    agrees: boolean;
  }>;
  media: Readonly<{
    attempts: readonly (string | null)[];
    final: string | null;
  }>;
  body: Readonly<{
    attempts: readonly Readonly<{
      disposition: BodyDisposition;
      pulledBytes: number;
      ceiling: number;
    }>[];
  }>;
  scope: Readonly<{
    start: "CURRENT";
    end: "CURRENT" | "STALE";
    signal: "ACTIVE" | "ABORTED";
    cancellationOwner: "NONE" | "CALLER" | "SCOPE_FENCE" | "DEADLINE";
  }>;
}>;

export const httpScenarioExpectationSchema = z
  .object({
    executionId: z.string().min(1),
    operationId: z.string().min(1),
    scenarioId: z.string().min(1),
    expected: httpScenarioAssertionGroupsSchema,
    testDeadlineOverrideMs: z.number().int().positive().nullable(),
  })
  .strict()
  .superRefine((entry, context) => {
    if (entry.executionId !== `${entry.operationId}::${entry.scenarioId}`) {
      context.addIssue({
        code: "custom",
        path: ["executionId"],
        message: "must equal operationId::scenarioId",
      });
    }
  });

export type HttpScenarioExpectation = Readonly<{
  executionId: string;
  operationId: string;
  scenarioId: string;
  expected: HttpScenarioAssertionGroups;
  testDeadlineOverrideMs: number | null;
}>;

export const httpScenarioReceiptRowSchema = z
  .object({
    executionId: z.string().min(1),
    expected: httpScenarioAssertionGroupsSchema,
    observed: httpScenarioAssertionGroupsSchema,
    testDeadlineOverrideMs: z.number().int().positive().nullable(),
  })
  .strict();

export const httpScenarioReceiptSchema = z
  .object({
    schemaVersion: z.number().int().positive(),
    catalogDigest: z.string().regex(/^sha256:[0-9a-f]{64}$/),
    catalogTotal: z.number().int().nonnegative(),
    executedIds: z.array(z.string().min(1)),
    rows: z.array(httpScenarioReceiptRowSchema),
  })
  .strict()
  .superRefine((receipt, context) => {
    const rowIds = receipt.rows.map((row) => row.executionId);
    const sortedIds = [...receipt.executedIds].sort((left, right) =>
      left.localeCompare(right),
    );
    const sortedRowIds = [...rowIds].sort((left, right) =>
      left.localeCompare(right),
    );
    if (!sameScenarioJson(receipt.executedIds, sortedIds)) {
      context.addIssue({
        code: "custom",
        path: ["executedIds"],
        message: "must be sorted by execution ID",
      });
    }
    if (!sameScenarioJson(rowIds, sortedRowIds)) {
      context.addIssue({
        code: "custom",
        path: ["rows"],
        message: "must be sorted by execution ID",
      });
    }
    if (!sameScenarioJson(receipt.executedIds, rowIds)) {
      context.addIssue({
        code: "custom",
        path: ["rows"],
        message: "row IDs must exactly equal executed IDs",
      });
    }
  });

export type HttpScenarioReceipt = Readonly<{
  schemaVersion: number;
  catalogDigest: string;
  catalogTotal: number;
  executedIds: readonly string[];
  rows: readonly Readonly<{
    executionId: string;
    expected: HttpScenarioAssertionGroups;
    observed: HttpScenarioAssertionGroups;
    testDeadlineOverrideMs: number | null;
  }>[];
}>;

export function stableScenarioJson(value: unknown): string {
  const normalize = (candidate: unknown): unknown => {
    if (Array.isArray(candidate)) return candidate.map(normalize);
    if (candidate && typeof candidate === "object") {
      return Object.fromEntries(
        Object.entries(candidate as Readonly<Record<string, unknown>>)
          .sort(([left], [right]) => left.localeCompare(right))
          .map(([key, nested]) => [key, normalize(nested)]),
      );
    }
    return candidate;
  };
  return JSON.stringify(normalize(value));
}

export function sameScenarioJson(left: unknown, right: unknown): boolean {
  return stableScenarioJson(left) === stableScenarioJson(right);
}

export function computeHttpScenarioCatalogDigest(
  schemaVersion: number,
  expectations: readonly HttpScenarioExpectation[],
): `sha256:${string}` {
  const tuples = [...expectations]
    .sort((left, right) => left.executionId.localeCompare(right.executionId))
    .map((entry) => [
      entry.executionId,
      entry.expected.status,
      entry.expected.outcome,
      entry.expected.effect,
      entry.expected.retry,
      entry.expected.fetch,
      entry.expected.media,
      entry.expected.body,
      entry.expected.scope,
      entry.testDeadlineOverrideMs,
    ]);
  return `sha256:${createHash("sha256")
    .update(stableScenarioJson([schemaVersion, ...tuples]))
    .digest("hex")}`;
}