import { config } from '../config/index.js';
import logger from '../utils/logger.js';
import { healthTracker } from './healthTracker.js';
import { observabilityService } from './observabilityService.js';

export interface WatchdogAutoResumeCycleMetrics {
    success: boolean;
    mismatchCount: number;
    missingFromExchange: number;
    missingInDb: number;
    noGoTrades: number;
    parityMismatchTrades: number;
    parityQuarantinedTrades: number;
    failedProfiles: number;
    integrityWatchdogTriggered: boolean;
}

export interface WatchdogAutoResumeDecision {
    attempted: boolean;
    resumed: boolean;
    reason?: string;
    cleanStreak: number;
}

const toPositiveInt = (value: unknown, fallback: number): number => {
    const parsed = Number(value);
    if (!Number.isFinite(parsed)) return fallback;
    return Math.max(0, Math.floor(parsed));
};

export class ReconciliationWatchdogAutoResumeService {
    private cleanCycleStreak = 0;
    private lastAutoResumeAt = 0;

    private isCleanCycle(metrics: WatchdogAutoResumeCycleMetrics): boolean {
        return metrics.success
            && metrics.failedProfiles === 0
            && metrics.mismatchCount === 0
            && metrics.missingFromExchange === 0
            && metrics.missingInDb === 0
            && metrics.noGoTrades === 0
            && metrics.parityMismatchTrades === 0
            && metrics.parityQuarantinedTrades === 0
            && !metrics.integrityWatchdogTriggered;
    }

    public evaluateCycle(metrics: WatchdogAutoResumeCycleMetrics): WatchdogAutoResumeDecision {
        if (!config.ENABLE_RECON_WATCHDOG_AUTO_RESUME) {
            this.cleanCycleStreak = 0;
            return { attempted: false, resumed: false, reason: 'disabled', cleanStreak: 0 };
        }

        const snapshot = healthTracker.getSnapshot();
        const control = snapshot.tradingControl;
        if (control.mode !== 'PAUSED') {
            this.cleanCycleStreak = 0;
            return { attempted: false, resumed: false, reason: 'not_paused', cleanStreak: 0 };
        }

        const changedBy = String(control.lastChangedBy || '').trim();
        if (!changedBy.startsWith('system:recon_parity_watchdog')) {
            this.cleanCycleStreak = 0;
            return { attempted: false, resumed: false, reason: 'pause_not_from_parity_watchdog', cleanStreak: 0 };
        }

        const now = Date.now();
        const minPauseMs = toPositiveInt(config.RECON_WATCHDOG_AUTO_RESUME_MIN_PAUSE_MS, 900_000);
        const pauseAgeMs = Math.max(0, now - Number(control.lastChangedAt || 0));
        if (pauseAgeMs < minPauseMs) {
            this.cleanCycleStreak = 0;
            return { attempted: true, resumed: false, reason: 'min_pause_window', cleanStreak: 0 };
        }

        if (!this.isCleanCycle(metrics)) {
            this.cleanCycleStreak = 0;
            return { attempted: true, resumed: false, reason: 'cycle_not_clean', cleanStreak: 0 };
        }

        const requiredCleanCycles = Math.max(1, toPositiveInt(config.RECON_WATCHDOG_AUTO_RESUME_CLEAN_CYCLES, 2));
        this.cleanCycleStreak += 1;
        if (this.cleanCycleStreak < requiredCleanCycles) {
            return {
                attempted: true,
                resumed: false,
                reason: `awaiting_clean_streak_${this.cleanCycleStreak}_of_${requiredCleanCycles}`,
                cleanStreak: this.cleanCycleStreak
            };
        }

        const cooldownMs = toPositiveInt(config.RECON_WATCHDOG_AUTO_RESUME_COOLDOWN_MS, 1_800_000);
        const sinceLastResumeMs = Math.max(0, now - this.lastAutoResumeAt);
        if (cooldownMs > 0 && this.lastAutoResumeAt > 0 && sinceLastResumeMs < cooldownMs) {
            return { attempted: true, resumed: false, reason: 'resume_cooldown', cleanStreak: this.cleanCycleStreak };
        }

        const reason = `Auto-resume after ${requiredCleanCycles} clean reconciliation cycles (pause_age_ms=${pauseAgeMs}, source=${changedBy}).`;
        healthTracker.recordTradingControl({
            mode: 'RUNNING',
            lastChangedBy: 'system:recon_parity_auto_resume',
            lastChangedAt: now,
            reason
        });

        logger.info(`[Reconcile] ${reason}`);
        observabilityService.emitEvent({
            type: 'PARITY_WARNING',
            severity: 'INFO',
            message: reason
        });

        this.lastAutoResumeAt = now;
        this.cleanCycleStreak = 0;
        return { attempted: true, resumed: true, reason: 'resumed', cleanStreak: 0 };
    }
}

export const reconciliationWatchdogAutoResumeService = new ReconciliationWatchdogAutoResumeService();