"""
ClaimSense — Agent 11: Triage & Routing Agent
===============================================
Deterministic rules engine. Makes final triage decision based on
outputs of all prior agents. No ML — pure business logic.

Outputs:
  AUTO_SETTLE      — low fraud, covered, minor/moderate → auto pay
  ADJUSTER_REVIEW  — standard review required
  SIU_REFERRAL     — Special Investigation Unit — high fraud score
  DENY             — excluded, invalid FNOL, or uncovered peril
"""

import logging
from datetime import datetime

log = logging.getLogger(__name__)


# ── Triage rules ─────────────────────────────────────────────
def _determine_outcome(fnol: dict, coverage: dict,
                       fraud: dict, severity: dict) -> tuple:
    """
    Returns (triage_outcome, priority, reasons)
    """
    reasons  = []
    outcome  = 'ADJUSTER_REVIEW'
    priority = 'MEDIUM'

    coverage_status = coverage.get('coverage_status', 'PENDING')
    fraud_score     = int(fraud.get('fraud_score') or 0)
    fraud_band      = fraud.get('fraud_band', 'LOW')
    severity_band   = severity.get('severity_band', 'MODERATE')
    reserve         = float(severity.get('reserve_estimate') or 0)
    fnol_status     = fnol.get('status', 'FNOL_ACCEPTED')
    fraud_flags     = fraud.get('fraud_flags', [])
    exclusions      = coverage.get('exclusions', [])

    # ── DENY conditions ───────────────────────────────────────
    if fnol_status == 'FNOL_INVALID':
        outcome  = 'DENY'
        priority = 'LOW'
        reasons.append("FNOL is invalid — missing required fields")
        return outcome, priority, reasons

    if coverage_status == 'EXCLUDED':
        outcome  = 'DENY'
        priority = 'LOW'
        reasons.append("Peril is excluded from coverage")
        reasons.extend(exclusions)
        return outcome, priority, reasons

    # ── SIU Referral ─────────────────────────────────────────
    if fraud_score >= 70:
        outcome  = 'SIU_REFERRAL'
        priority = 'HIGH'
        reasons.append(f"High fraud score: {fraud_score}/100")
        reasons.extend(fraud_flags[:3])
        return outcome, priority, reasons

    # ── Auto-settle conditions ────────────────────────────────
    if (
        coverage_status == 'COVERED'
        and fraud_band == 'LOW'
        and fraud_score < 25
        and severity_band in ('MINOR', 'MODERATE')
        and reserve < 25000
        and fnol_status == 'FNOL_ACCEPTED'
    ):
        outcome  = 'AUTO_SETTLE'
        priority = 'LOW'
        reasons.append("All checks passed — eligible for automated settlement")
        reasons.append(f"Fraud score {fraud_score}/100 (LOW band)")
        reasons.append(f"Reserve estimate ${reserve:,.0f} below auto-settle threshold")
        return outcome, priority, reasons

    # ── Adjuster review ───────────────────────────────────────
    if severity_band == 'CATASTROPHIC':
        priority = 'URGENT'
        reasons.append("CATASTROPHIC severity — executive escalation")
    elif severity_band == 'MAJOR':
        priority = 'HIGH'
        reasons.append("MAJOR severity — senior adjuster required")
    elif fraud_band == 'MEDIUM':
        priority = 'HIGH'
        reasons.append(f"Moderate fraud indicators detected (score: {fraud_score})")
    elif coverage_status == 'PARTIAL':
        reasons.append("Partial coverage — adjuster must determine applicable amount")
    else:
        reasons.append("Standard claim routed to adjuster queue")

    return outcome, priority, reasons


def _assign_queue(outcome: str, severity_band: str,
                  incident_type: str) -> str:
    """Map outcome + severity to adjuster queue name."""
    if outcome == 'AUTO_SETTLE':
        return 'AUTOMATED_SETTLEMENT'
    if outcome == 'SIU_REFERRAL':
        return 'SPECIAL_INVESTIGATIONS_UNIT'
    if outcome == 'DENY':
        return 'CLAIMS_DENIAL_REVIEW'

    # ADJUSTER_REVIEW
    if severity_band == 'CATASTROPHIC':
        return 'MAJOR_LOSS_TEAM'
    if severity_band == 'MAJOR':
        return 'SENIOR_ADJUSTER_QUEUE'
    if incident_type in ('FIRE', 'STRUCTURAL', 'EARTHQUAKE', 'FLOOD'):
        return 'PROPERTY_DAMAGE_QUEUE'
    if incident_type in ('LIABILITY',):
        return 'LIABILITY_CLAIMS_QUEUE'
    return 'STANDARD_ADJUSTER_QUEUE'


def _build_triage_summary(claim_id: str, outcome: str, priority: str,
                          fraud: dict, severity: dict,
                          coverage: dict, reasons: list) -> str:
    fraud_score   = fraud.get('fraud_score', 0)
    severity_band = severity.get('severity_band', '')
    reserve       = severity.get('reserve_estimate', 0)
    cov_status    = coverage.get('coverage_status', '')

    outcome_text = {
        'AUTO_SETTLE':     'approved for automated settlement',
        'ADJUSTER_REVIEW': 'routed to adjuster review',
        'SIU_REFERRAL':    'referred to the Special Investigation Unit',
        'DENY':            'recommended for denial',
    }.get(outcome, outcome)

    return (
        f"Claim {claim_id} has been {outcome_text}. "
        f"Coverage status is {cov_status}. "
        f"Fraud score: {fraud_score}/100. "
        f"Severity: {severity_band}. "
        f"Initial reserve estimate: ${float(reserve):,.0f}. "
        f"Priority: {priority}. "
        + (" ".join(reasons[:2]) if reasons else "")
    )


# ── Main agent function ───────────────────────────────────────
def run_triage_agent(fnol_result: dict, coverage_result: dict,
                     fraud_result: dict, severity_result: dict) -> dict:
    claim_id = fnol_result.get('claim_id', '')
    log.info(f"[TRIAGE] Agent 11 running for {claim_id}")

    outcome, priority, reasons = _determine_outcome(
        fnol_result, coverage_result, fraud_result, severity_result
    )

    incident_type    = fnol_result.get('incident_type', 'OTHER')
    severity_band    = severity_result.get('severity_band', 'MODERATE')
    adjuster_queue   = _assign_queue(outcome, severity_band, incident_type)
    reserve          = float(severity_result.get('reserve_estimate') or 0)
    fraud_score      = int(fraud_result.get('fraud_score') or 0)

    overall_summary = _build_triage_summary(
        claim_id, outcome, priority,
        fraud_result, severity_result, coverage_result, reasons
    )

    # ── Decision factors for AXIOM audit ─────────────────────
    decision_factors = [
        {
            'agent':   'FNOL Intake Agent',
            'factor':  'FNOL Completeness',
            'outcome': fnol_result.get('status', ''),
            'detail':  (
                f"Completeness score: {fnol_result.get('completeness_score', 0)}%. "
                f"Days to report: {fnol_result.get('days_to_report', 0)}. "
                f"Issues: {len(fnol_result.get('validation_issues', []))}."
            )
        },
        {
            'agent':   'Coverage Verification Agent',
            'factor':  'Policy Coverage Check',
            'outcome': coverage_result.get('coverage_status', ''),
            'detail':  coverage_result.get('summary', '')
        },
        {
            'agent':   'Fraud Signal Agent',
            'factor':  'Fraud Risk Scoring',
            'outcome': fraud_result.get('fraud_band', ''),
            'detail':  (
                f"Fraud score: {fraud_score}/100. "
                f"Band: {fraud_result.get('fraud_band', '')}. "
                f"Flags: {len(fraud_result.get('fraud_flags', []))}."
            )
        },
        {
            'agent':   'Severity & Reserve Agent',
            'factor':  'Severity Classification',
            'outcome': severity_band,
            'detail':  (
                f"Severity: {severity_band}. "
                f"Reserve estimate: ${reserve:,.0f}. "
                f"{severity_result.get('reserve_note', '')}."
            )
        },
        {
            'agent':   'Triage & Routing Agent',
            'factor':  'Final Triage Decision',
            'outcome': outcome,
            'detail':  " ".join(reasons)
        },
    ]

    result = {
        'claim_id':          claim_id,
        'status':            'TRIAGE_COMPLETE',
        'triage_outcome':    outcome,
        'triage_priority':   priority,
        'adjuster_queue':    adjuster_queue,
        'triage_reasons':    reasons,
        'overall_summary':   overall_summary,
        'decision_factors':  decision_factors,
        'reserve_estimate':  reserve,
        'fraud_score':       fraud_score,
        'severity_band':     severity_band,
        'coverage_status':   coverage_result.get('coverage_status', ''),
        'triaged_at':        datetime.utcnow().isoformat(),
    }

    log.info(
        f"[TRIAGE] {claim_id}: outcome={outcome} priority={priority} "
        f"queue={adjuster_queue}"
    )
    return result