import fs from 'node:fs';
import path from 'node:path';

type MonitorOptions = {
    hours: number;
    intervalSec: number;
    outFile: string;
    healthUrl: string;
    stateFile: string;
};

type HealthSnapshot = {
    tradingLoopHealthy?: boolean;
    monitorLoopHealthy?: boolean;
    reconciliationLoopHealthy?: boolean;
    reconciliationMismatchCount?: number;
    reconciliationMissingFromExchange?: number;
    reconciliationMissingInDb?: number;
    reconciliationNoGoTrades?: number;
    reconciliationIntegrityWatchdogTriggered?: boolean;
    tradingControl?: {
        mode?: string;
        lastChangedBy?: string;
        lastChangedAt?: number;
        reason?: string;
    };
};

const toNumber = (value: unknown, fallback: number): number => {
    const parsed = Number(value);
    return Number.isFinite(parsed) ? parsed : fallback;
};

const parseArgs = (argv: string[]): MonitorOptions => {
    let hours = 12;
    let intervalSec = 60;
    let outFile = '';
    let healthUrl = 'http://127.0.0.1:5000/internal/health';
    let stateFile = path.resolve(process.cwd(), 'bot_state.json');

    for (const arg of argv) {
        if (arg.startsWith('--hours=')) {
            hours = Math.max(1, Math.floor(toNumber(arg.slice('--hours='.length), 12)));
            continue;
        }
        if (arg.startsWith('--interval-sec=')) {
            intervalSec = Math.max(15, Math.floor(toNumber(arg.slice('--interval-sec='.length), 60)));
            continue;
        }
        if (arg.startsWith('--out=')) {
            outFile = String(arg.slice('--out='.length) || '').trim();
            continue;
        }
        if (arg.startsWith('--health-url=')) {
            healthUrl = String(arg.slice('--health-url='.length) || '').trim() || healthUrl;
            continue;
        }
        if (arg.startsWith('--state-file=')) {
            const candidate = String(arg.slice('--state-file='.length) || '').trim();
            if (candidate) stateFile = path.resolve(process.cwd(), candidate);
        }
    }

    if (!outFile) {
        const stamp = new Date().toISOString().replace(/[:]/g, '-');
        outFile = path.resolve(process.cwd(), `logs/fresh-window-monitor-${stamp}.jsonl`);
    } else {
        outFile = path.resolve(process.cwd(), outFile);
    }

    return {
        hours,
        intervalSec,
        outFile,
        healthUrl,
        stateFile
    };
};

const wait = async (ms: number): Promise<void> => {
    await new Promise((resolve) => setTimeout(resolve, ms));
};

const readStateEventSummary = (stateFile: string, fromTimestampMs: number): {
    operationalEventsCount: number;
    latestEventType: string;
    latestEventSeverity: string;
    latestEventMessage: string;
    latestEventAt: number;
} => {
    try {
        if (!fs.existsSync(stateFile)) {
            return {
                operationalEventsCount: 0,
                latestEventType: '',
                latestEventSeverity: '',
                latestEventMessage: '',
                latestEventAt: 0
            };
        }
        const raw = fs.readFileSync(stateFile, 'utf8');
        const parsed = JSON.parse(raw);
        const allEvents = Array.isArray(parsed?.operationalEvents) ? parsed.operationalEvents : [];
        const events = allEvents.filter((row: any) => {
            const ts = Number(row?.timestamp || 0);
            return ts >= fromTimestampMs;
        });
        const latest = events.length > 0 ? events[events.length - 1] : null;
        return {
            operationalEventsCount: events.length,
            latestEventType: String(latest?.type || '').trim(),
            latestEventSeverity: String(latest?.severity || '').trim(),
            latestEventMessage: String(latest?.message || '').trim(),
            latestEventAt: Number(latest?.timestamp || 0) || 0
        };
    } catch {
        return {
            operationalEventsCount: 0,
            latestEventType: 'STATE_READ_ERROR',
            latestEventSeverity: 'WARN',
            latestEventMessage: 'Failed to parse bot_state.json',
            latestEventAt: Date.now()
        };
    }
};

const appendJsonLine = (file: string, row: Record<string, unknown>): void => {
    const dir = path.dirname(file);
    if (!fs.existsSync(dir)) {
        fs.mkdirSync(dir, { recursive: true });
    }
    fs.appendFileSync(file, `${JSON.stringify(row)}\n`, 'utf8');
};

const fetchHealth = async (healthUrl: string): Promise<HealthSnapshot | null> => {
    try {
        const response = await fetch(healthUrl, { method: 'GET' });
        if (!response.ok) return null;
        const payload = await response.json();
        return payload as HealthSnapshot;
    } catch {
        return null;
    }
};

const run = async (): Promise<void> => {
    const options = parseArgs(process.argv.slice(2));
    const startedAtMs = Date.now();
    const endAtMs = startedAtMs + (options.hours * 60 * 60 * 1000);

    appendJsonLine(options.outFile, {
        type: 'monitor_started',
        at: startedAtMs,
        iso: new Date(startedAtMs).toISOString(),
        options
    });

    while (Date.now() < endAtMs) {
        const now = Date.now();
        const health = await fetchHealth(options.healthUrl);
        const stateSummary = readStateEventSummary(options.stateFile, startedAtMs);
        const mode = String(health?.tradingControl?.mode || 'UNKNOWN').toUpperCase();
        const mismatch = Number(health?.reconciliationMismatchCount || 0);
        const missingDb = Number(health?.reconciliationMissingInDb || 0);
        const noGo = Number(health?.reconciliationNoGoTrades || 0);
        const watchdog = Boolean(health?.reconciliationIntegrityWatchdogTriggered);
        const healthyLoops = Boolean(health?.tradingLoopHealthy) && Boolean(health?.monitorLoopHealthy) && Boolean(health?.reconciliationLoopHealthy);
        const severity = (mode !== 'RUNNING' || mismatch > 0 || missingDb > 0 || noGo > 0 || watchdog || !healthyLoops) ? 'WARN' : 'INFO';

        appendJsonLine(options.outFile, {
            type: 'monitor_tick',
            severity,
            at: now,
            iso: new Date(now).toISOString(),
            mode,
            tradingLoopHealthy: Boolean(health?.tradingLoopHealthy),
            monitorLoopHealthy: Boolean(health?.monitorLoopHealthy),
            reconciliationLoopHealthy: Boolean(health?.reconciliationLoopHealthy),
            reconciliationMismatchCount: mismatch,
            reconciliationMissingFromExchange: Number(health?.reconciliationMissingFromExchange || 0),
            reconciliationMissingInDb: missingDb,
            reconciliationNoGoTrades: noGo,
            reconciliationIntegrityWatchdogTriggered: watchdog,
            tradingControlChangedBy: String(health?.tradingControl?.lastChangedBy || ''),
            tradingControlReason: String(health?.tradingControl?.reason || ''),
            operationalEventsCount: stateSummary.operationalEventsCount,
            latestEventType: stateSummary.latestEventType,
            latestEventSeverity: stateSummary.latestEventSeverity,
            latestEventMessage: stateSummary.latestEventMessage,
            latestEventAt: stateSummary.latestEventAt
        });

        await wait(options.intervalSec * 1000);
    }

    const endedAtMs = Date.now();
    appendJsonLine(options.outFile, {
        type: 'monitor_finished',
        at: endedAtMs,
        iso: new Date(endedAtMs).toISOString(),
        elapsedSec: Math.floor((endedAtMs - startedAtMs) / 1000)
    });

    console.log(JSON.stringify({
        success: true,
        outFile: options.outFile,
        startedAt: new Date(startedAtMs).toISOString(),
        endedAt: new Date(endedAtMs).toISOString()
    }, null, 2));
};

run().catch((error) => {
    console.error(JSON.stringify({
        success: false,
        error: error instanceof Error ? error.message : String(error)
    }, null, 2));
    process.exit(1);
});