#!/usr/bin/env node

const fs = require("fs");
const path = require("path");
const { spawn } = require("child_process");
const { chromium } = require("playwright");

const serverPort = 4173;
const baseUrl = `http://127.0.0.1:${serverPort}`;
const repoRoot = path.resolve(__dirname, "../../..");

function readArg(name, fallback) {
    const idx = process.argv.indexOf(name);
    if (idx < 0 || idx + 1 >= process.argv.length) return fallback;
    return process.argv[idx + 1];
}

function parsePositiveInt(name, fallback) {
    const value = Number.parseInt(readArg(name, String(fallback)), 10);
    if (Number.isNaN(value) || value <= 0) return fallback;
    return value;
}

function parseOptionalNumber(name) {
    const raw = readArg(name, null);
    if (raw === null) return null;
    const value = Number.parseFloat(raw);
    return Number.isFinite(value) ? value : null;
}

function hasFlag(name) {
    return process.argv.includes(name);
}

function buildSummary(results) {
    return {
        games_played: results.length,
        won: results.filter((r) => r.terminal === "won").length,
        no_moves: results.filter((r) => r.terminal === "no_moves").length,
        cycle: results.filter((r) => r.terminal === "cycle").length,
        step_budget: results.filter((r) => r.terminal === "step_budget").length,
        apply_failed: results.filter((r) => r.terminal === "apply_failed").length,
        invariant_failed: results.filter((r) => r.terminal === "invariant_failed").length,
        missing_snapshot: results.filter((r) => r.terminal === "missing_snapshot").length,
        games_with_issues: results.filter((r) => r.issues.length > 0).length,
        with_page_errors: results.filter((r) => r.page_errors > 0).length,
        with_console_errors: results.filter((r) => r.console_errors > 0).length,
        draw1: results.filter((r) => !r.draw3).length,
        draw3: results.filter((r) => r.draw3).length,
    };
}

function withRates(results, predicate) {
    const subset = results.filter(predicate);
    const won = subset.filter((r) => r.terminal === "won").length;
    const cycle = subset.filter((r) => r.terminal === "cycle").length;
    const stepBudget = subset.filter((r) => r.terminal === "step_budget").length;
    return {
        games: subset.length,
        won,
        win_rate_pct: subset.length === 0 ? 0 : Number(((won / subset.length) * 100).toFixed(1)),
        cycle,
        cycle_rate_pct:
            subset.length === 0 ? 0 : Number(((cycle / subset.length) * 100).toFixed(1)),
        step_budget: stepBudget,
        step_budget_rate_pct:
            subset.length === 0 ? 0 : Number(((stepBudget / subset.length) * 100).toFixed(1)),
    };
}

async function waitForHealth(timeoutMs = 120_000) {
    const start = Date.now();
    while (Date.now() - start < timeoutMs) {
        try {
            const res = await fetch(`${baseUrl}/health`);
            if (res.ok) return true;
        } catch {
            // server not ready yet
        }
        await new Promise((resolve) => setTimeout(resolve, 400));
    }
    return false;
}

function startServer() {
    return spawn("cargo", ["run", "-p", "solitaire_server", "--quiet"], {
        cwd: repoRoot,
        env: {
            ...process.env,
            SQLX_OFFLINE: "true",
            DATABASE_URL: "sqlite://ferrous-solitaire-e2e.db",
            JWT_SECRET: "ferrous_solitaire_e2e_secret_32_chars_long",
            SERVER_PORT: String(serverPort),
        },
        stdio: ["ignore", "pipe", "pipe"],
    });
}

async function main() {
    const games = parsePositiveInt("--games", 1000);
    const maxSteps = parsePositiveInt("--steps", 350);
    const maxVisitsPerState = parsePositiveInt("--max-visits", 2);
    const policyArg = readArg("--policy", "loop_aware");
    const policy = policyArg === "baseline" ? "baseline" : "loop_aware";
    const outPath = readArg("--out", "/tmp/playwright-cycle-metrics.json");
    // --route play-classic (default) or --route play
    const routeArg = readArg("--route", "play-classic");
    const route = routeArg === "play" ? "play" : "play-classic";
    const maxCycleRateAll = parseOptionalNumber("--max-cycle-rate-all");
    const maxCycleRateDraw1 = parseOptionalNumber("--max-cycle-rate-draw1");
    const maxCycleRateDraw3 = parseOptionalNumber("--max-cycle-rate-draw3");
    const maxStepBudgetRateAll = parseOptionalNumber("--max-step-budget-rate-all");
    const maxStepBudgetRateDraw1 = parseOptionalNumber("--max-step-budget-rate-draw1");
    const maxStepBudgetRateDraw3 = parseOptionalNumber("--max-step-budget-rate-draw3");
    const minWinRateAll = parseOptionalNumber("--min-win-rate-all");
    const requireZeroIssues = hasFlag("--require-zero-issues");

    const server = startServer();
    let serverLog = "";
    server.stdout.on("data", (d) => {
        serverLog += d.toString();
    });
    server.stderr.on("data", (d) => {
        serverLog += d.toString();
    });

    const cleanup = async () => {
        if (!server.killed) {
            server.kill("SIGTERM");
            await new Promise((resolve) => setTimeout(resolve, 500));
            if (!server.killed) server.kill("SIGKILL");
        }
    };

    try {
        if (!(await waitForHealth())) {
            throw new Error("server_failed_health_check");
        }

        const browser = await chromium.launch({ headless: true });
        const context = await browser.newContext();
        const page = await context.newPage();
        const results = [];

        for (let i = 0; i < games; i++) {
            const seed = i;
            const draw3 = i % 2 === 1;
            const suffix = draw3 ? "&draw3=" : "";

            const pageErrors = [];
            const consoleErrors = [];
            page.removeAllListeners("pageerror");
            page.removeAllListeners("console");
            page.on("pageerror", (err) => pageErrors.push(String(err)));
            page.on("console", (msg) => {
                if (msg.type() === "error") {
                    consoleErrors.push(msg.text());
                }
            });

            await page.goto(`${baseUrl}/${route}?seed=${seed}${suffix}`, {
                waitUntil: "domcontentloaded",
            });

            if (route === "play-classic") {
                const resumeVisible = await page
                    .locator("#resume-overlay:not(.hidden)")
                    .isVisible()
                    .catch(() => false);
                if (resumeVisible) {
                    await page.evaluate(() => localStorage.removeItem("fs_game_save"));
                    await page.reload({ waitUntil: "domcontentloaded" });
                }
            }

            await page.waitForFunction(
                () =>
                    typeof window.__FERROUS_DEBUG__ === "object" &&
                    window.__FERROUS_DEBUG__.seed() !== null,
                null,
                { timeout: 30_000 }
            );

            const run = await page.evaluate(({ stepCap, policyName, maxVisits }) => {
                const debug = window.__FERROUS_DEBUG__;
                const run = debug.runAutoplay({
                    maxSteps: stepCap,
                    maxVisitsPerState: maxVisits,
                    policy: policyName,
                });
                const snap = run.snapshot || debug.snapshot();
                const payload = debug.replayPayload();

                return {
                    terminal: run.terminal || "unknown",
                    step: run.step ?? -1,
                    error: run.error || run.reason || null,
                    ok: !!run.ok,
                    score: snap?.state?.score ?? null,
                    move_count: snap?.state?.move_count ?? null,
                    invariant_ok: !!snap?.invariants?.state_ok,
                    history_len: Array.isArray(snap?.move_history) ? snap.move_history.length : null,
                    replay_payload_present: payload !== null,
                    replay_moves_len: Array.isArray(payload?.moves) ? payload.moves.length : 0,
                };
            }, { stepCap: maxSteps, policyName: policy, maxVisits: maxVisitsPerState });

            const issues = [];
            if (!run.ok) issues.push(`autoplay_failed:${run.error || run.terminal || "unknown"}`);
            if (!run.invariant_ok) issues.push("invariant_not_ok");
            if (run.terminal === "invariant_failed") issues.push("invariant_failed_terminal");
            if (run.terminal === "missing_snapshot") issues.push("missing_snapshot_terminal");
            if (run.terminal === "apply_failed") issues.push(`apply_failed:${run.error}`);
            if (run.history_len > 0 && !run.replay_payload_present) {
                issues.push("missing_replay_payload_after_moves");
            }
            if (
                run.replay_payload_present &&
                run.history_len !== null &&
                run.replay_moves_len !== run.history_len
            ) {
                issues.push(`replay_history_mismatch:${run.replay_moves_len}/${run.history_len}`);
            }
            if (pageErrors.length > 0) issues.push(`page_errors:${pageErrors.length}`);
            if (consoleErrors.length > 0) issues.push(`console_errors:${consoleErrors.length}`);

            results.push({
                game_index: i,
                seed,
                draw3,
                ...run,
                page_errors: pageErrors.length,
                console_errors: consoleErrors.length,
                issues,
            });

            if ((i + 1) % 100 === 0) {
                console.error(`progress ${i + 1}/${games}`);
            }
        }

        const summary = buildSummary(results);
        const rates = {
            all: withRates(results, () => true),
            draw1: withRates(results, (r) => !r.draw3),
            draw3: withRates(results, (r) => r.draw3),
        };
        const regressionFailures = [];
        if (maxCycleRateAll !== null && rates.all.cycle_rate_pct > maxCycleRateAll) {
            regressionFailures.push(
                `all.cycle_rate_pct ${rates.all.cycle_rate_pct}% > ${maxCycleRateAll}%`
            );
        }
        if (maxCycleRateDraw1 !== null && rates.draw1.cycle_rate_pct > maxCycleRateDraw1) {
            regressionFailures.push(
                `draw1.cycle_rate_pct ${rates.draw1.cycle_rate_pct}% > ${maxCycleRateDraw1}%`
            );
        }
        if (maxCycleRateDraw3 !== null && rates.draw3.cycle_rate_pct > maxCycleRateDraw3) {
            regressionFailures.push(
                `draw3.cycle_rate_pct ${rates.draw3.cycle_rate_pct}% > ${maxCycleRateDraw3}%`
            );
        }
        if (minWinRateAll !== null && rates.all.win_rate_pct < minWinRateAll) {
            regressionFailures.push(
                `all.win_rate_pct ${rates.all.win_rate_pct}% < ${minWinRateAll}%`
            );
        }
        if (maxStepBudgetRateAll !== null && rates.all.step_budget_rate_pct > maxStepBudgetRateAll) {
            regressionFailures.push(
                `all.step_budget_rate_pct ${rates.all.step_budget_rate_pct}% > ${maxStepBudgetRateAll}%`
            );
        }
        if (
            maxStepBudgetRateDraw1 !== null &&
            rates.draw1.step_budget_rate_pct > maxStepBudgetRateDraw1
        ) {
            regressionFailures.push(
                `draw1.step_budget_rate_pct ${rates.draw1.step_budget_rate_pct}% > ${maxStepBudgetRateDraw1}%`
            );
        }
        if (
            maxStepBudgetRateDraw3 !== null &&
            rates.draw3.step_budget_rate_pct > maxStepBudgetRateDraw3
        ) {
            regressionFailures.push(
                `draw3.step_budget_rate_pct ${rates.draw3.step_budget_rate_pct}% > ${maxStepBudgetRateDraw3}%`
            );
        }
        if (requireZeroIssues) {
            if (summary.games_with_issues > 0) {
                regressionFailures.push(`games_with_issues ${summary.games_with_issues} > 0`);
            }
            if (summary.apply_failed > 0) {
                regressionFailures.push(`apply_failed ${summary.apply_failed} > 0`);
            }
            if (summary.invariant_failed > 0) {
                regressionFailures.push(`invariant_failed ${summary.invariant_failed} > 0`);
            }
            if (summary.missing_snapshot > 0) {
                regressionFailures.push(`missing_snapshot ${summary.missing_snapshot} > 0`);
            }
            if (summary.with_page_errors > 0) {
                regressionFailures.push(`with_page_errors ${summary.with_page_errors} > 0`);
            }
            if (summary.with_console_errors > 0) {
                regressionFailures.push(`with_console_errors ${summary.with_console_errors} > 0`);
            }
        }

        const out = {
            config: {
                games,
                max_steps: maxSteps,
                policy,
                max_visits_per_state: maxVisitsPerState,
            },
            summary,
            rates,
            regression: {
                pass: regressionFailures.length === 0,
                thresholds: {
                    max_cycle_rate_all: maxCycleRateAll,
                    max_cycle_rate_draw1: maxCycleRateDraw1,
                    max_cycle_rate_draw3: maxCycleRateDraw3,
                    max_step_budget_rate_all: maxStepBudgetRateAll,
                    max_step_budget_rate_draw1: maxStepBudgetRateDraw1,
                    max_step_budget_rate_draw3: maxStepBudgetRateDraw3,
                    min_win_rate_all: minWinRateAll,
                    require_zero_issues: requireZeroIssues,
                },
                failures: regressionFailures,
            },
            issue_samples: results
                .filter((r) => r.issues.length > 0)
                .slice(0, 25)
                .map((r) => ({
                    seed: r.seed,
                    draw3: r.draw3,
                    terminal: r.terminal,
                    issues: r.issues,
                    score: r.score,
                    move_count: r.move_count,
                })),
            cycle_samples: results
                .filter((r) => r.terminal === "cycle")
                .slice(0, 25)
                .map((r) => ({
                    seed: r.seed,
                    draw3: r.draw3,
                    step: r.step,
                    score: r.score,
                    move_count: r.move_count,
                })),
        };

        fs.mkdirSync(path.dirname(outPath), { recursive: true });
        fs.writeFileSync(outPath, JSON.stringify({ out, results }, null, 2));
        console.log(JSON.stringify(out, null, 2));
        if (regressionFailures.length > 0) {
            console.error(`regression check failed: ${regressionFailures.join("; ")}`);
            await browser.close();
            await cleanup();
            process.exit(2);
        }

        await browser.close();
        await cleanup();
    } catch (err) {
        const errorOut = {
            error: String(err),
            server_log_tail: serverLog.slice(-5000),
        };
        fs.mkdirSync(path.dirname(outPath), { recursive: true });
        fs.writeFileSync(outPath, JSON.stringify(errorOut, null, 2));
        console.error(JSON.stringify(errorOut, null, 2));
        await cleanup();
        process.exit(1);
    }
}

main();