/**
 * Debugging each language's `fixtures/` project the way the editor does: a breakpoint on the
 * entry point's "Set a breakpoint here" line, Debug from the file's context (or a saved
 * configuration, when the debugger is an explicit choice), then the paused frame, its
 * variables, evaluation, Step Over and Resume, with the debugger the IDE installs (GDB:
 * the toolchain's own, 14+ for its DAP interpreter).
 */
import { execFileSync } from "node:child_process";
import { cpSync, existsSync, mkdtempSync, readdirSync, readFileSync, realpathSync, rmSync, statSync } from "node:fs";
import { get } from "node:http";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { afterAll, afterEach, beforeAll, expect, test } from "vitest";
import { Channel } from "@tauri-apps/api/core";
import { commands, type HeapProgress, type InstallEvent } from "@/bindings";
import { executeAction } from "@/platform/actions";
import { call, nextRequestId, onIdeEvent } from "@/platform/ipc";
import { useBuildModel } from "@/platform/buildModel";
import { openProject, useProject } from "@/platform/project";
import { activate as activateBuildTools } from "@/features/build-tools";
import { useBuild } from "@/features/build-tools/store";
import { activate as activateDebugger } from "@/features/debugger";
import { addBreakpoint } from "@/features/debugger/breakpoints/store";
import { activeSession, evaluate, rootOf, sessionSupports, useDebug } from "@/features/debugger/state";
import { activate as activateRun } from "@/features/run";
import { resetRuns, useRun } from "@/features/run/store";
import { activateWorkbench } from "@/workbench/activate";
import { useNotifications } from "@/workbench/notificationStore";
import { connectDesktop } from "./desktop";
import { repoRoot, Server } from "./server";

interface Case {
  fixture: string;
  /** Runs in the project copy first (installs its dependencies). */
  setup?: (root: string) => void;
  /** The IDE's tools that debug it, installed unless found. */
  tools: string[];
  /** The adapter of the session Debug starts. */
  adapter: string;
  /** A system tool that ships with the toolchain (the IDE does not install it): `adapter` is run to check it. */
  system?: boolean;
  /** A saved configuration to debug (the debugger is its explicit choice), instead of the file's context. */
  configId?: string;
  /** Global settings (key: value) written before the project opens. */
  settings?: Record<string, unknown>;
  /** The title of a notification Debug shows. */
  notice?: string;
  /** Instances, fields and referrers may answer `timedOut` while the adapter is still busy after a stop. */
  retryTimedOut?: boolean;
  /** The entry point, debugged from its context. */
  file: string;
  /** A variable of the paused frame. */
  variable: string;
  /** Its value once the adapter has filled in a placeholder (`invalidated`), as the Variables pane shows it. */
  filledValue?: RegExp;
  /** An expression evaluated there (Evaluate Expression), and its value. */
  evaluate: [string, RegExp];
  /** A server: the breakpoint is in this request's handler, and the session is stopped at the end. */
  request?: string;
  /** JVM languages: the live instances of a class the paused program holds (Memory tab). */
  memory?: { className: string; instances: number };
  /** JVM languages: a class of the heap snapshot captured there and its instance count. */
  heap?: { className: string; instances: number };
  /** JVM languages: that class's instances, a field of the first one and its referrers (Show Instances). */
  instances?: { className: string; count: number; field: string };
}

/** Debugging the Kotlin fixture, with either debugger. */
const kotlin = {
  fixture: "kotlin-gradle",
  file: "src/main/kotlin/com/example/library/App.kt",
  variable: "library",
  evaluate: ["library", /Library/] as [string, RegExp],
  // Gradle forks the JVM and the debugger attaches to it: the attach-session path.
  memory: { className: "com.example.library.Book", instances: 3 },
  heap: { className: "com.example.library.Book", instances: 3 },
  instances: { className: "com.example.library.Book", count: 3, field: "title" },
};

const CASES: Record<string, Case> = {
  typescript: {
    fixture: "ts-app",
    setup: (root) => execFileSync("npm", ["install", "--no-audit", "--no-fund"], { cwd: root, stdio: "ignore" }),
    tools: ["js-debug"],
    adapter: "js-debug",
    file: "src/index.ts",
    variable: "cart",
    evaluate: ["cart.items.length", /^2$/],
  },
  python: {
    fixture: "python-app",
    setup: (root) => execFileSync("python3", ["-m", "venv", ".venv"], { cwd: root, stdio: "ignore" }),
    tools: ["debugpy"],
    adapter: "debugpy",
    file: "src/tasks/cli.py",
    variable: "tasks",
    evaluate: ["len(tasks.pending())", /^3$/],
  },
  rust: {
    fixture: "rust-app",
    tools: ["codelldb"],
    adapter: "codelldb",
    file: "src/main.rs",
    variable: "inventory",
    evaluate: ["inventory", /\S/],
  },
  go: {
    fixture: "go-app",
    tools: ["delve"],
    adapter: "delve",
    file: "cmd/server/main.go",
    variable: "r",
    evaluate: ["r.Method", /^"GET"$/],
    request: "http://127.0.0.1:8080/notes?q=openidea",
  },
  java: {
    fixture: "java-app",
    tools: ["java-debug"],
    adapter: "java-debug",
    file: "src/main/java/com/example/orders/App.java",
    variable: "book",
    evaluate: ["book.size()", /^3$/],
    memory: { className: "com.example.orders.OrderBook", instances: 1 },
    heap: { className: "com.example.orders.OrderBook", instances: 1 },
    instances: { className: "com.example.orders.OrderBook", count: 1, field: "orders" },
  },
  kotlin: {
    ...kotlin,
    tools: ["kotlin-lsp"],
    adapter: "kotlin-lsp",
    // kotlin-lsp evaluates for itself after each stop, which the inspector's link waits out.
    retryTimedOut: true,
    // First "Collecting data…", then the `toString` kotlin-lsp invokes.
    filledValue: /Library@/,
  },
  "kotlin-fwcd": {
    ...kotlin,
    tools: ["kotlin-debug-adapter"],
    adapter: "kotlin-debug-adapter",
    settings: { languageServers: { "kotlin-lsp": { enabled: false } } },
    notice: "Debugging Kotlin with kotlin-debug-adapter",
  },
  // GDB's own DAP interpreter (GDB 14+), the configuration's explicit debugger choice:
  // the C/C++ default stays lldb-dap. GDB 15.0.50.20240403-0ubuntu1 says `15`.
  c: {
    fixture: "c-app",
    setup: (root) => execFileSync("make", ["app-c"], { cwd: root, stdio: "ignore" }),
    tools: [],
    adapter: "gdb",
    system: true,
    configId: "user:app-c",
    file: "src/main.c",
    variable: "value",
    evaluate: ["print value", / = [0-9]/],
  },
  cpp: {
    fixture: "c-app",
    setup: (root) => execFileSync("make", ["app-cpp"], { cwd: root, stdio: "ignore" }),
    tools: [],
    adapter: "gdb",
    system: true,
    configId: "user:app-cpp",
    file: "src/main.cpp",
    variable: "line",
    evaluate: ["print line", / = /],
  },
  php: {
    fixture: "php-app",
    setup: (root) =>
      execFileSync("composer", ["install", "--no-interaction", "--no-progress"], { cwd: root, stdio: "ignore" }),
    tools: ["php-debug"],
    adapter: "php-debug",
    file: "bin/quote.php",
    variable: "$shipment",
    evaluate: ["count($shipment)", /^3$/],
  },
};

let deactivate: (() => void) | null = null;
let server: Server | null = null;
let disconnect: (() => void) | null = null;
let base = "";

/** Backend events received, for failure messages. */
const events: string[] = [];
beforeAll(() => {
  onIdeEvent("*", (e) =>
    events.push(
      e.type === "debug"
        ? `debug ${e.session} ${e.event.kind}`
        : e.type === "task"
          ? `task ${e.title}${e.done ? " (done)" : ""}`
          : e.type,
    ),
  );
  const disposers = [activateWorkbench(), activateBuildTools(), activateRun(), activateDebugger()];
  deactivate = () => disposers.reverse().forEach((d) => d());
});
afterAll(() => deactivate?.());

afterEach(async () => {
  resetRuns();
  disconnect?.();
  // `close` kills the server and what it started (debug adapters, language servers)
  // and waits until they're gone, so the removal below can't race their writes.
  await server?.close();
  if (base) rmSync(base, { recursive: true, force: true, maxRetries: 5, retryDelay: 200 });
});

async function open(c: Case): Promise<string> {
  base = realpathSync(mkdtempSync(join(tmpdir(), "openidea-smoke-")));
  const root = join(base, c.fixture);
  cpSync(join(repoRoot, "fixtures", c.fixture), root, { recursive: true });
  c.setup?.(root);
  server = await Server.start(join(base, "home"));
  disconnect = connectDesktop(server);
  for (const [key, value] of Object.entries(c.settings ?? {}))
    await call(commands.settingsSet("global", key, JSON.stringify(value)));
  await openProject(root);
  const trusted = await commands.projectTrustSet(root, true, false);
  if (trusted.status !== "ok") throw new Error(trusted.error.message);
  useProject.setState({ project: { ...useProject.getState().project!, trusted: true } });
  // Run and Debug follow the build (a Gradle project's Application runs through Gradle).
  await until(
    "the build model",
    () => {
      const error = useBuild.getState().error;
      if (error) throw new Error(`the build model did not load: ${error}`);
      return useBuildModel.getState().root === root && useBuildModel.getState().model;
    },
    5 * 60_000,
  );
  return root;
}

async function install(tool: string) {
  const tools = await call(commands.toolsList());
  // CI puts its pinned kotlin-lsp on `PATH`: that one is tested, not the latest release.
  const status = tools.find((t) => t.name === tool)?.status;
  if (status === "installed" || status === "onPath") return;
  const channel = new Channel<InstallEvent>();
  const info = await call(commands.toolsInstall(tool, nextRequestId(), channel));
  expect(info.status, `${tool} installs`).toBe("installed");
}

/** What the Debug and Run tool windows show, for failure messages. */
function shown(): string {
  const { sessions, console } = useDebug.getState();
  const debug = Object.values(sessions).map(
    (s) =>
      `debug ${s.id} ${s.name} ${s.status} ${s.stopReason ?? ""}\n` +
      (console[s.id] ?? [])
        .slice(-40)
        .map((l) => `  ${l.text}`)
        .join(""),
  );
  const runs = useRun.getState().sessions.map((s) => `run ${s.id} ${s.config.name} ${s.status} ${s.exitCode ?? ""}`);
  const notes = useNotifications.getState().items.map((n) => `${n.level}: ${n.title} ${n.body ?? ""}`);
  return [...debug, ...runs, ...notes, `events: ${events.slice(-60).join(", ")}`, server?.log() ?? ""].join("\n");
}

/** Waits for `value` to be truthy; fails with what the tool windows show. */
async function until<T>(what: string, value: () => T | null | undefined | false, timeoutMs = 60_000): Promise<T> {
  const end = Date.now() + timeoutMs;
  for (;;) {
    const v = value();
    if (v) return v;
    if (Date.now() > end) throw new Error(`timed out waiting for ${what}\n${shown()}`);
    await new Promise((r) => setTimeout(r, 200));
  }
}

/** Requests `url` once the debugged server accepts connections (the response waits for Resume). */
async function requestWhenListening(url: string) {
  for (let i = 0; i < 600; i++) {
    const connected = await new Promise<boolean>((resolve) => {
      const req = get(url, (res) => {
        res.resume();
        resolve(true);
      });
      req.on("socket", (socket) => socket.on("connect", () => resolve(true)));
      req.on("error", () => resolve(false));
    });
    if (connected) return;
    await new Promise((r) => setTimeout(r, 500));
  }
}

const paused = () => {
  const s = activeSession();
  return s?.status === "paused" && s.frames.length > 0 ? s : null;
};

/** Paused, failing as soon as every session has ended instead. */
const pausedOrEnded = () => {
  const sessions = Object.values(useDebug.getState().sessions);
  if (sessions.length > 0 && sessions.every((s) => s.status === "terminated"))
    throw new Error(`the debugger ended before the breakpoint\n${shown()}`);
  return paused();
};

async function smoke(language: string) {
  const c = CASES[language]!;
  const root = await open(c);
  // GDB ships with the toolchain (14+ for its DAP interpreter); the IDE does not install it.
  if (c.system) execFileSync(c.adapter, ["--version"], { stdio: "pipe" });
  for (const tool of c.tools) await install(tool);

  const path = join(root, c.file);
  const content = readFileSync(path, "utf8");
  const marker = content.split("\n").findIndex((l) => l.includes("Set a breakpoint here"));
  const line = marker + 1;
  addBreakpoint(path, line);

  const started = Date.now();
  const begun = events.length;
  if (c.configId) {
    const config = (await call(commands.runConfigs())).find((cfg) => cfg.id === c.configId);
    expect(config, c.configId).toBeTruthy();
    await executeAction("debug.startConfig", config);
  } else {
    await executeAction("run.debugContext", { path, content });
  }
  if (c.request) void requestWhenListening(c.request);
  const s = await until("the breakpoint", pausedOrEnded, 5 * 60_000);
  const firstStop = Date.now() - started;
  expect(s.stopReason, `${s.stopDescription}\n${shown()}`).toBe("breakpoint");
  expect(rootOf(s).adapter, shown()).toBe(c.adapter);
  if (c.notice) {
    const titles = useNotifications.getState().items.map((n) => n.title);
    expect(titles, shown()).toContain(c.notice);
  }
  const top = s.frames[0]!;
  expect(top.path).toBe(path);
  expect(top.line).toBe(line);

  const scopes = await call(commands.debugScopes(s.id, top.id));
  let locals = await call(commands.debugVariables(s.id, scopes[0]!.variablesReference));
  expect(locals.map((v) => v.name)).toContain(c.variable);
  let filled = "";
  if (c.filledValue) {
    const since = Date.now();
    let epoch: number | null = null;
    let last = locals.find((v) => v.name === c.variable)?.value;
    while (!c.filledValue.test(last ?? "")) {
      if (Date.now() - since > 10_000) throw new Error(`${c.variable} stayed ${JSON.stringify(last)}\n${shown()}`);
      const now = useDebug.getState().variablesEpoch;
      if (now === epoch) {
        await new Promise((r) => setTimeout(r, 100));
        continue;
      }
      // What the Variables pane does on each `invalidated`: pull the frame's locals again.
      epoch = now;
      const again = await call(commands.debugScopes(s.id, top.id));
      locals = await call(commands.debugVariables(s.id, again.find((sc) => !sc.expensive)!.variablesReference));
      last = locals.find((v) => v.name === c.variable)?.value;
    }
    filled = ` (filled in after ${((Date.now() - since) / 1000).toFixed(1)} s)`;
  }

  // The value, not kotlin-lsp's "Collecting data…" placeholder.
  const value = await evaluate(c.evaluate[0], "repl", s);
  expect(value.value, c.evaluate[0]).toMatch(c.evaluate[1]);
  if (c.adapter === "gdb") {
    const expression = await evaluate(c.variable, "watch", s);
    expect(expression.value).toBeTruthy();
    const environment = await evaluate("environment_ok", "watch", s);
    expect(environment.value).toBe("1");
  }

  const filters = (await call(commands.debugExceptionFilters())).find((f) => f.session === rootOf(s).id);
  const filterIds = filters?.filters.map((f) => f.filter) ?? [];
  // The JVM debuggers offer caught / uncaught exceptions; Delve offers none.
  if (c.memory) expect(filterIds, `exception filters of ${c.adapter}`).not.toHaveLength(0);
  const waits = events.slice(begun).filter((e) => e.startsWith("task Waiting for")).length;
  console.info(
    `${language}: ${c.adapter} stopped after ${(firstStop / 1000).toFixed(1)} s (${waits} wait task events); ` +
      `${c.variable} = ${locals.find((v) => v.name === c.variable)?.value}${filled}; evaluated ${value.value}; ` +
      `exception filters [${filterIds.join(", ")}]`,
  );

  if (c.memory) {
    const memory = await call(commands.debugJvmMemoryClasses(s.id));
    if (memory.status === "ready") {
      const row = memory.snapshot.rows.find((r) => r.name === c.memory!.className);
      expect(row?.instances, `${c.memory.className} in the histogram\n${shown()}`).toBe(c.memory.instances);
    } else {
      // Attaching to a suspended JVM older than 17 hangs, so the backend refuses it by design.
      const { reason } = memory;
      const refused = reason.kind === "unsafeWhileSuspended" && reason.javaMajor > 0 && reason.javaMajor < 17;
      expect(refused, `memory unavailable: ${JSON.stringify(reason)}\n${shown()}`).toBe(true);
    }
  }

  if (c.heap) {
    const { className, instances } = c.heap;
    const snapshots = join(base, "home", "data", "cache", "heap-snapshots");
    const dirs = () =>
      existsSync(snapshots)
        ? readdirSync(snapshots, { withFileTypes: true })
            .filter((e) => e.isDirectory())
            .map((e) => e.name)
        : [];
    const phases: string[] = [];
    const progress = new Channel<HeapProgress>();
    progress.onmessage = (p) => {
      const phase = p.type === "dumping" ? "dumping" : p.phase;
      if (phases.at(-1) !== phase) phases.push(phase);
    };
    const since = Date.now();
    const captured = await call(commands.debugHeapCapture(s.id, nextRequestId(), progress));
    const captureMs = Date.now() - since;
    if (captured.status === "unavailable") {
      // The same refusal as the class table's, for the same reason.
      const { reason } = captured;
      const refused =
        reason.kind === "memory" &&
        reason.reason.kind === "unsafeWhileSuspended" &&
        reason.reason.javaMajor > 0 &&
        reason.reason.javaMajor < 17;
      expect(refused, `heap unavailable: ${JSON.stringify(reason)}\n${shown()}`).toBe(true);
    } else {
      if (captured.status !== "ready") throw new Error(`heap capture: ${JSON.stringify(captured)}\n${shown()}`);
      const { snapshot } = captured;
      const held = dirs();
      expect(held, "snapshot directories while open").toHaveLength(1);
      const dumpBytes = statSync(join(snapshots, held[0]!, "dump.hprof")).size;
      const classes = await call(commands.debugHeapClasses(snapshot.id));
      const row = classes.find((r) => r.name === className);
      expect(row?.count, `${className} in the heap snapshot`).toBe(instances);
      expect(row!.shallow, `${className} shallow size`).toBeGreaterThan(0);
      expect(row!.retained, `${className} retained size`).toBeGreaterThanOrEqual(row!.shallow);
      const page = await call(commands.debugHeapDominators(snapshot.id, null, row!.classIndex, 0, 1));
      expect(page.rows, `${className} dominator rows`).toHaveLength(1);
      const path = await call(commands.debugHeapPath(snapshot.id, page.rows[0]!.object));
      const last = path?.steps.at(-1)?.via;
      expect(last?.kind, `path to a GC root: ${JSON.stringify(path)}`).toBe("root");
      await call(commands.debugHeapClose(snapshot.id));
      expect(dirs(), "snapshot directories after close").toEqual([]);
      const origin = snapshot.origin;
      const java = origin.kind === "captured" ? `JDK ${origin.javaVersion}, dump ${origin.dumpMs} ms` : origin.kind;
      console.info(
        `${language}: heap snapshot in ${captureMs} ms (${java}, analysis ${snapshot.summary.analysisMs} ms, ` +
          `${dumpBytes} bytes, ${snapshot.summary.objects} objects; ${phases.join(" → ")}); ` +
          `${className} ${row!.count} / ${row!.shallow} B / retained ${row!.retained} B, ${page.total} reachable; ` +
          `path ${path!.steps.length + path!.omitted} steps to ${last?.kind === "root" ? last.root : "?"}`,
      );
    }
  }

  let timedOutRetries = 0;
  if (c.instances) {
    const { className, count, field } = c.instances;
    // The inspector comes up beside the session (jdtls bundle, Kotlin JDWP link).
    await until("the JVM inspector", () => {
      const session = useDebug.getState().sessions[s.id] ?? null;
      const backend = session?.jvmBackend;
      if (backend && backend.kind !== "ready") throw new Error(`JVM inspector ${JSON.stringify(backend)}\n${shown()}`);
      return sessionSupports("jvmInstances", session);
    });
    type Answer = { status: "ready" } | { status: "unavailable"; reason: { kind: string } };
    const ready = async <T extends Answer>(what: string, ask: () => Promise<T>) => {
      let r = await ask();
      for (let retry = 0; c.retryTimedOut && retry < 5; retry++) {
        if (r.status !== "unavailable" || r.reason.kind !== "timedOut") break;
        timedOutRetries++;
        await new Promise((resolve) => setTimeout(resolve, 500));
        r = await ask();
      }
      expect(r.status, `${what}: ${JSON.stringify(r)}\n${shown()}`).toBe("ready");
      return r as Extract<T, { status: "ready" }>;
    };
    const listed = await ready("instances", () => call(commands.debugJvmMemoryInstances(s.id, className, 1000)));
    expect(listed.instances, `${className} instances`).toHaveLength(count);
    const first = listed.instances[0]!;
    if (!("id" in first)) throw new Error(`${className} instance without an id: ${JSON.stringify(first)}`);
    const object = { generation: listed.generation, id: first.id };
    const fields = await ready("fields", () => call(commands.debugJvmMemoryFields(s.id, object)));
    const held = fields.fields.find((f) => f.name === field)?.value;
    if (!held || !("id" in held)) throw new Error(`${className}.${field}: ${JSON.stringify(fields.fields)}`);
    // Only objects count as referrers, not stack frames: Java's `OrderBook` is held by a local alone.
    await ready("referrers", () => call(commands.debugJvmMemoryReferrers(s.id, object, 50)));
    const heldRef = { generation: listed.generation, id: held.id };
    const referrers = await ready("referrers", () => call(commands.debugJvmMemoryReferrers(s.id, heldRef, 50)));
    const back = referrers.referrers.find((r) => "id" in r.value && r.value.id === first.id);
    expect(back?.via, `referrers of ${className}.${field}: ${JSON.stringify(referrers)}`).toContain(field);
  }

  const stepped = events.length;
  // Python 3.12 reports a conditional expression's line twice: Step Over may stop on it
  // (and its breakpoint) again.
  for (let step = 0; step < 3 && paused()!.frames[0]!.line === line; step++) {
    const stops = useDebug.getState().stopSeq;
    await executeAction("debug.stepOver");
    await until("Step Over", () => useDebug.getState().stopSeq > stops && paused());
  }
  const after = paused()!;
  expect(after.stopReason, shown()).toBe("step");
  expect(after.frames[0]!.line, shown()).toBeGreaterThan(line);

  const invalidated = (from: number, to = events.length) =>
    events.slice(from, to).filter((e) => e.endsWith(" invalidated")).length;
  console.info(
    `${language}: invalidated ${invalidated(begun, stepped)} at the breakpoint, ${invalidated(stepped)} after Step Over; ` +
      `${timedOutRetries} timedOut retries`,
  );

  await executeAction("debug.resume");
  if (c.request) {
    await until("the request to be served", () => useDebug.getState().sessions[s.id]?.status === "running");
    await executeAction("debug.stop");
  }
  // Every session ends (a JVM that listens again as its debugger detaches may be attached once more).
  await until("the end", () => Object.values(useDebug.getState().sessions).every((d) => d.status === "terminated"));
}

for (const language of Object.keys(CASES)) {
  test(language, () => smoke(language));
}