import { createHash } from "node:crypto";

import { describe, expect, it } from "vitest";

import { compareBrowserScenarios } from "./browserScenarioDiff.js";
import {
  compareBrowserScenariosInputSchema,
  browserScenarioDiffSchema,
} from "./browserScenarioDiffValues.js";
import {
  browserScenarioCaptureSchema,
  type BrowserScenarioCapture,
} from "./browserScenarioCapture.js";

const networkCapture = (sourceSequence: number, receiptStep: number) => {
  const base = scenarioCapture({});
  const events = [
    {
      sequence: sourceSequence,
      step_index: 0,
      kind: "request",
      method: "POST",
      url: {
        url: "https://app.example.test/api",
        origin: "https://app.example.test",
        query_parameter_names: [],
        redacted: false,
      },
      resource_type: "fetch",
      transaction_id: "request-1",
      redirected_from_transaction_id: null,
      header_names: [],
      status: null,
      failure: null,
    },
    {
      sequence: sourceSequence + 1,
      step_index: receiptStep,
      kind: "network-content",
      transaction_id: "request-1",
      phase: "request",
      source_event_sequence: sourceSequence,
      headers: { state: "not_requested" },
      body: {
        state: "captured",
        representation: "browser-exposed-request-bytes",
        encoding: "base64",
        content: "eA==",
        bytes: 1,
        sha256: createHash("sha256").update("x").digest("hex"),
        media_type: null,
        redacted: false,
      },
    },
  ];
  return browserScenarioCaptureSchema.parse({
    ...base,
    scenario: {
      ...base.scenario,
      network_content: {
        request_body: true,
        response_body: false,
        header_values: false,
      },
    },
    events: { items: events, retained: 2, dropped: 0 },
  });
};

it("normalizes network content anchors and attributes late content to its source step", () => {
  const before = networkCapture(3, 0);
  const after = networkCapture(90, 1);
  expect(
    compareBrowserScenarios(
      compareBrowserScenariosInputSchema.parse({
        before_scenario: before,
        after_scenario: after,
      }),
    ).overall_status,
  ).toBe("unchanged");
  const content = after.events.items[1];
  if (content?.kind !== "network-content")
    throw new Error("Expected content fixture");
  for (const mutation of [
    { transaction_id: "another-request" },
    { source_event_sequence: 91 },
    { phase: "response" },
  ])
    expect(
      browserScenarioCaptureSchema.safeParse({
        ...after,
        events: {
          ...after.events,
          items: [after.events.items[0], { ...content, ...mutation }],
        },
      }).success,
    ).toBe(false);
});

it("reports content-selection mismatch as unknown instead of a website change", () => {
  const withBody = networkCapture(1, 0);
  const metadataOnly = browserScenarioCaptureSchema.parse({
    ...withBody,
    scenario: {
      ...withBody.scenario,
      network_content: {
        request_body: false,
        response_body: false,
        header_values: false,
      },
    },
    events: {
      ...withBody.events,
      items: withBody.events.items.filter(
        (event) => event.kind !== "network-content",
      ),
      retained: 1,
    },
  });
  const compared = compareBrowserScenarios(
    compareBrowserScenariosInputSchema.parse({
      before_scenario: metadataOnly,
      after_scenario: withBody,
    }),
  );
  expect(compared.overall_status).toBe("unknown");
  expect(compared.steps.flatMap((step) => step.artifact_diffs)).toContainEqual(
    expect.objectContaining({
      artifact: "events",
      status: "unknown",
      reason: expect.stringContaining("content selections differ"),
    }),
  );
  for (const networkContent of [undefined, {}, { request_body: false }])
    expect(
      compareBrowserScenariosInputSchema.safeParse({
        before_scenario: {
          ...metadataOnly,
          scenario: {
            ...metadataOnly.scenario,
            network_content: networkContent,
          },
        },
        after_scenario: withBody,
      }).success,
    ).toBe(false);
});

describe("browser scenario comparison", () => {
  it("records canonical literal normalization and ignores declared volatile fields", () => {
    const before = scenarioCapture({
      domText: "<main data-build='build-123'>Settings</main>",
      elapsedMs: 11,
      eventSequence: 3,
    });
    const after = scenarioCapture({
      domText: "<main data-build='build-456'>Settings</main>",
      elapsedMs: 900,
      eventSequence: 88,
    });
    const rules = [
      {
        rule_id: "new-build",
        artifacts: ["dom"] as const,
        match: "build-456",
        replacement: "[BUILD]",
      },
      {
        rule_id: "old-build",
        artifacts: ["dom"] as const,
        match: "build-123",
        replacement: "[BUILD]",
      },
    ];

    const compared = compareBrowserScenarios(
      compareBrowserScenariosInputSchema.parse({
        before_scenario: before,
        after_scenario: after,
        normalization: { rules },
      }),
    );
    const reordered = compareBrowserScenarios(
      compareBrowserScenariosInputSchema.parse({
        before_scenario: before,
        after_scenario: after,
        normalization: {
          rules: [...rules].reverse().map((rule) => ({
            ...rule,
            artifacts: [...rule.artifacts].reverse(),
          })),
        },
      }),
    );

    expect(compared.overall_status).toBe("unchanged");
    expect(compared.alignment.status).toBe("aligned");
    expect(compared.artifact_diffs.total).toBe(0);
    expect(compared.normalization).toMatchObject({
      rules: [
        { rule_id: "new-build", artifacts: ["dom"] },
        { rule_id: "old-build", artifacts: ["dom"] },
      ],
    });
    expect(reordered.normalization.sha256).toBe(compared.normalization.sha256);
  });

  it("exposes action mismatches and normalized artifact-level changes", () => {
    const before = scenarioCapture({
      domText: "<main>Settings</main>",
    });
    const after = scenarioCapture({
      action: "dblclick",
      domText: "<main>Advanced settings</main>",
    });

    const compared = compareBrowserScenarios(
      compareBrowserScenariosInputSchema.parse({
        before_scenario: before,
        after_scenario: after,
      }),
    );
    const step = compared.steps.find(
      ({ step_id: stepId }) => stepId === "open-settings",
    );

    expect(compared.overall_status).toBe("changed");
    expect(compared.alignment).toMatchObject({
      status: "partial",
      failures: [
        expect.objectContaining({
          code: "action_mismatch",
          step_id: "open-settings",
        }),
      ],
    });
    expect(step).toMatchObject({
      status: "changed",
      artifact_diffs: [
        expect.objectContaining({
          artifact: "action_state",
          status: "changed",
        }),
        expect.objectContaining({ artifact: "dom", status: "changed" }),
      ],
    });
    expect(compared.artifact_diffs).toEqual({ total: 2 });
  });
});

describe("browser scenario comparison text values", () => {
  it("accepts long normalization values and comparison diagnostics", () => {
    const longText = "x".repeat(5_000);
    const ruleId = "r".repeat(100);
    const capture = scenarioCapture({});
    const compared = compareBrowserScenarios(
      compareBrowserScenariosInputSchema.parse({
        before_scenario: capture,
        after_scenario: capture,
        normalization: {
          rules: [
            {
              rule_id: ruleId,
              artifacts: ["dom"],
              match: longText,
              replacement: longText,
            },
          ],
        },
      }),
    );
    const stepId = "s".repeat(100);
    const diagnostic = browserScenarioDiffSchema.parse({
      ...compared,
      alignment: {
        ...compared.alignment,
        before_only: [stepId],
        after_only: [stepId],
        failures: [
          {
            code: "missing_before_step",
            step_id: stepId,
            reason: longText,
          },
        ],
      },
      steps: compared.steps.map((step) => ({
        ...step,
        step_id: stepId,
        artifact_diffs: [
          {
            artifact: "dom",
            status: "unknown",
            before_state: "missing",
            after_state: "missing",
            before_sha256: null,
            after_sha256: null,
            reason: longText,
          },
        ],
      })),
      limitations: [longText],
    });

    expect(diagnostic.normalization.rules[0]).toMatchObject({
      rule_id: ruleId,
      match: longText,
      replacement: longText,
    });
    expect(diagnostic.alignment.failures[0]?.reason).toBe(longText);
    expect(diagnostic.steps[0]?.artifact_diffs[0]?.reason).toBe(longText);
    expect(diagnostic.limitations).toEqual([longText]);
  });
});

describe("browser scenario comparison validation", () => {
  it("does not accept caller limits that would omit difference records", () => {
    const capture = scenarioCapture({});
    expect(
      compareBrowserScenariosInputSchema.safeParse({
        before_scenario: capture,
        after_scenario: capture,
        max_changes: 1,
      }).success,
    ).toBe(false);
  });

  it("returns every aligned step beyond the former capture ceiling", () => {
    const before = multiStepScenarioCapture(130, "before");
    const after = multiStepScenarioCapture(130, "after");
    const result = compareBrowserScenarios(
      compareBrowserScenariosInputSchema.parse({
        before_scenario: before,
        after_scenario: after,
      }),
    );

    expect(result.alignment).toMatchObject({
      status: "aligned",
      aligned_steps: 131,
    });
    expect(result.steps).toHaveLength(131);
    expect(result.steps.at(-1)).toMatchObject({
      before_step_index: 130,
      after_step_index: 130,
      status: "changed",
    });
    expect(result.artifact_diffs.total).toBe(130);
  });

  it("reports missing aligned steps without claiming equality", () => {
    const before = scenarioCapture({});
    const after = scenarioCapture({ stepId: "open-profile" });

    const compared = compareBrowserScenarios(
      compareBrowserScenariosInputSchema.parse({
        before_scenario: before,
        after_scenario: after,
      }),
    );

    expect(compared.overall_status).toBe("unknown");
    expect(compared.alignment).toMatchObject({
      status: "partial",
      aligned_steps: 1,
      before_only: ["open-settings"],
      after_only: ["open-profile"],
      failures: expect.arrayContaining([
        expect.objectContaining({
          code: "missing_before_step",
          step_id: "open-profile",
        }),
        expect.objectContaining({
          code: "missing_after_step",
          step_id: "open-settings",
        }),
      ]),
    });
  });

  it("rejects duplicate normalization rule IDs", () => {
    const capture = scenarioCapture({});
    expect(
      compareBrowserScenariosInputSchema.safeParse({
        before_scenario: capture,
        after_scenario: capture,
        normalization: {
          rules: [
            {
              rule_id: "volatile",
              artifacts: ["dom"],
              match: "one",
              replacement: "[VALUE]",
            },
            {
              rule_id: "volatile",
              artifacts: ["url"],
              match: "two",
              replacement: "[VALUE]",
            },
          ],
        },
      }).success,
    ).toBe(false);
  });
});

const multiStepScenarioCapture = (
  actionCount: number,
  content: string,
): BrowserScenarioCapture => {
  const capture = scenarioCapture({});
  const template = capture.steps[1];
  if (template === undefined) throw new Error("Expected scenario action step");
  const steps = [
    capture.steps[0],
    ...Array.from({ length: actionCount }, (_, index) => ({
      ...template,
      step_index: index + 1,
      step_id: `step-${String(index + 1)}`,
      event_sequence_start: index + 1,
      event_sequence_end: index + 1,
      artifacts: {
        ...template.artifacts,
        dom: {
          state: "captured" as const,
          value: textArtifact(`${content}-${String(index + 1)}`),
        },
      },
    })),
  ];
  return browserScenarioCaptureSchema.parse({
    ...capture,
    scenario: { ...capture.scenario, action_count: actionCount },
    steps,
  });
};

interface ScenarioCaptureOptions {
  readonly stepId?: string;
  readonly action?: string;
  readonly domText?: string;
  readonly elapsedMs?: number;
  readonly eventSequence?: number;
}

const scenarioCapture = (
  options: ScenarioCaptureOptions,
): BrowserScenarioCapture => {
  const url = {
    url: "https://app.example.test/settings",
    origin: "https://app.example.test",
    query_parameter_names: [],
    redacted: false,
  };
  const completeness = {
    status: "complete",
    equality_eligible: true,
    missing_sections: [],
    truncated_sections: [],
  };
  const artifacts = (text: string) => ({
    screenshot: { state: "not_requested" },
    dom: { state: "captured", value: textArtifact(text) },
    accessibility: { state: "not_requested" },
    url: { state: "captured", value: url },
    history: { state: "not_requested" },
    storage: { state: "not_requested" },
  });
  const eventSequence = options.eventSequence ?? 1;
  return browserScenarioCaptureSchema.parse({
    browser: {
      mode: "launch",
      process_ownership: "provider-owned",
      cleanup: "terminated-owned-process",
      product: "Chromium",
      version: "149.0",
    },
    scenario: {
      start_origin: "https://app.example.test",
      action_count: 1,
      secret_references: [],
      network_content: {
        request_body: false,
        response_body: false,
        header_values: false,
      },
    },
    duration_ms: options.elapsedMs ?? 10,
    steps: [
      {
        step_index: 0,
        step_id: "scenario_start",
        action: "scenario_start",
        status: "completed",
        elapsed_ms: 0,
        before_url: url,
        after_url: url,
        error: null,
        event_sequence_start: 1,
        event_sequence_end: 0,
        artifacts: artifacts("<main>Ready</main>"),
        completeness,
      },
      {
        step_index: 1,
        step_id: options.stepId ?? "open-settings",
        action: options.action ?? "click",
        status: "completed",
        elapsed_ms: options.elapsedMs ?? 10,
        before_url: url,
        after_url: url,
        error: null,
        event_sequence_start: eventSequence,
        event_sequence_end: eventSequence,
        artifacts: artifacts(options.domText ?? "<main>Settings</main>"),
        completeness,
      },
    ],
    events: {
      retained: 1,
      dropped: 0,
      items: [
        {
          sequence: eventSequence,
          step_index: 1,
          kind: "console",
          level: "info",
          text: "settings-ready",
          url: null,
        },
      ],
    },
    completeness,
    limitations: [],
  });
};

const textArtifact = (text: string) => {
  const bytes = Buffer.from(text);
  return {
    sha256: createHash("sha256").update(bytes).digest("hex"),
    bytes: bytes.byteLength,
    text,
  };
};