"""Deterministic claim analysis: a 0-100 score, a plain-English narrative,
a recommended starting tier, and a recommended collection letter assembled
from the tier templates in /root/.hermes/references/dre-letter-templates.md.

Transparent rules engine (no external LLM) so every score is explainable and
auditable for FDCPA/TDCPA compliance. To move to an LLM later, swap the
generator behind these functions and keep the return shape identical.
"""
from __future__ import annotations

import json
import uuid
from datetime import datetime, timezone

TIER_ORDER = ["TIER_1", "TIER_2", "TIER_2_5", "TIER_3", "TIER_4"]

TIER_LABELS = {
    "TIER_1": "Tier 1 - Soft Touch",
    "TIER_2": "Tier 2 - Formal Demand",
    "TIER_2_5": "Tier 2.5 - Lien Threat",
    "TIER_3": "Tier 3 - Escalation",
    "TIER_4": "Tier 4 - Legal Action",
}

TIER_DESCRIPTIONS = {
    "TIER_1": "Friendly reminder email + ACH payment link (Day 1-5)",
    "TIER_2": "Formal demand letter via certified mail (Day 7-14)",
    "TIER_2_5": "Pre-lien notice for construction claims (Day 15-21)",
    "TIER_3": "Final notice before legal action (Day 21-30)",
    "TIER_4": "Referral to partner law firm (Day 30+)",
}


def next_tier(current: str) -> str | None:
    """Return the tier after `current` in the escalation order, or None at Tier 4."""
    if current not in TIER_ORDER:
        return None
    i = TIER_ORDER.index(current)
    return TIER_ORDER[i + 1] if i + 1 < len(TIER_ORDER) else None


def _age_days(invoice_date: str | None) -> int | None:
    if not invoice_date:
        return None
    try:
        d = datetime.strptime(invoice_date[:10], "%Y-%m-%d")
        d = d.replace(tzinfo=timezone.utc)
        return (datetime.now(timezone.utc) - d).days
    except (ValueError, TypeError):
        return None


def score_claim(*, amount_cents: int, business_type: str, doc_count: int,
                description: str | None, invoice_date: str | None,
                client_reference: str | None) -> dict:
    """Compute a 0-100 analysis score with a component breakdown and narrative.

    Returns:
        {"score": int, "components": {name: {points, max, note}}, "summary": str,
         "recommended_tier": str}
    """
    components: dict[str, dict] = {}

    # 1. Amount (0-25) — higher balance = higher recovery priority.
    if amount_cents >= 1_000_000:
        components["amount"] = {"points": 25, "max": 25, "note": "High-value claim ($10k+)"}
    elif amount_cents >= 500_000:
        components["amount"] = {"points": 20, "max": 25, "note": "Significant balance ($5k-$10k)"}
    elif amount_cents >= 250_000:
        components["amount"] = {"points": 15, "max": 25, "note": "Moderate balance ($2.5k-$5k)"}
    elif amount_cents >= 100_000:
        components["amount"] = {"points": 10, "max": 25, "note": "Low balance ($1k-$2.5k)"}
    elif amount_cents >= 50_000:
        components["amount"] = {"points": 6, "max": 25, "note": "Small balance ($500-$1k)"}
    else:
        components["amount"] = {"points": 3, "max": 25, "note": "Minimal balance (<$500)"}

    # 2. Documentation (0-25) — evidence quality drives collectability.
    if doc_count >= 4:
        components["documentation"] = {"points": 25, "max": 25, "note": f"{doc_count} documents on file"}
    elif doc_count >= 2:
        components["documentation"] = {"points": 18, "max": 25, "note": f"{doc_count} documents on file"}
    elif doc_count == 1:
        components["documentation"] = {"points": 12, "max": 25, "note": "1 document on file"}
    else:
        components["documentation"] = {"points": 5, "max": 25, "note": "No evidence uploaded yet"}

    # 3. Collectability by debtor entity type (0-20).
    collect = {
        "LLC": (20, "Registered LLC - assets traceable"),
        "CORPORATION": (20, "Registered corporation - assets traceable"),
        "PARTNERSHIP": (16, "Partnership"),
        "SOLE_PROPRIETORSHIP": (12, "Sole proprietorship"),
        "INDIVIDUAL": (8, "Individual debtor"),
        "OTHER": (10, "Other entity type"),
    }
    pts, note = collect.get(business_type, (10, "Other entity type"))
    components["collectability"] = {"points": pts, "max": 20, "note": note}

    # 4. Claim completeness (0-20) — how fully the intake form was filled.
    comp = 0
    if description:
        comp += 8
    if invoice_date:
        comp += 6
    if client_reference:
        comp += 6
    components["completeness"] = {
        "points": comp, "max": 20,
        "note": "Description, invoice date, and client reference provided",
    }

    # 5. Debt age (0-10) — fresher debt is more collectable.
    age = _age_days(invoice_date)
    if age is None:
        age_pts, age_note = 2, "Invoice date not provided"
    elif age <= 90:
        age_pts, age_note = 10, f"{age} days old (fresh)"
    elif age <= 180:
        age_pts, age_note = 8, f"{age} days old"
    elif age <= 365:
        age_pts, age_note = 6, f"{age} days old"
    elif age <= 730:
        age_pts, age_note = 3, f"{age} days old (stale)"
    else:
        age_pts, age_note = 2, f"{age} days old (very stale)"
    components["age"] = {"points": age_pts, "max": 10, "note": age_note}

    score = sum(c["points"] for c in components.values())

    # Recommended starting tier from score band.
    if score >= 75:
        rec = "TIER_1"
        rec_note = "Strong case; soft touch should resolve"
    elif score >= 60:
        rec = "TIER_2"
        rec_note = "Solid case; begin with formal demand"
    elif score >= 40:
        rec = "TIER_3"
        rec_note = "Moderate case; escalate if initial contact fails"
    else:
        rec = "TIER_4"
        rec_note = "Weak or high-effort case; review carefully before accepting"

    summary = (
        f"Analysis score {score}/100. {rec_note}. "
        f"Key factors: {components['amount']['note']}; "
        f"{components['documentation']['note']}; "
        f"{components['collectability']['note']}; "
        f"{components['age']['note']}."
    )

    return {
        "score": score,
        "components": components,
        "summary": summary,
        "recommended_tier": rec,
    }


def analyze_and_store(conn, claim_id: str, actor: str = "staff") -> dict:
    """Run score_claim for a claim and persist score/approval + audit row.

    Single source of truth for analysis persistence, shared by the staff
    /analyze endpoint (actor="staff") and post-intake auto-analysis
    (actor="system"). Returns the score_claim() result dict.

    Assumes the caller owns the transaction and will commit.
    """
    row = conn.execute(
        "SELECT c.id, c.amount_cents, c.description, c.invoice_date, c.client_reference, "
        "d.business_type FROM claims c JOIN debtors d ON d.id = c.debtor_id "
        "WHERE c.id = ?",
        (claim_id,),
    ).fetchone()
    if row is None:
        raise ValueError(f"claim not found: {claim_id}")
    doc_count = conn.execute(
        "SELECT COUNT(*) AS n FROM documents WHERE claim_id = ?", (claim_id,)
    ).fetchone()["n"]
    result = score_claim(
        amount_cents=row["amount_cents"],
        business_type=row["business_type"],
        doc_count=doc_count,
        description=row["description"],
        invoice_date=row["invoice_date"],
        client_reference=row["client_reference"],
    )
    now = datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%SZ")
    conn.execute(
        "UPDATE claims SET analysis_score = ?, analysis_summary = ?, analysis_components = ?, "
        "analysis_at = ?, recommended_tier = ?, approval_status = 'PENDING', updated_at = ? WHERE id = ?",
        (result["score"], result["summary"], json.dumps(result["components"]),
         now, result["recommended_tier"], now, claim_id),
    )
    conn.execute(
        "INSERT INTO audit_log (id, entity_type, entity_id, action, field, old_value, new_value, actor, reason, created_at) "
        "VALUES (?, 'claim', ?, 'analysis', 'analysis_score', NULL, ?, ?, NULL, ?)",
        (str(uuid.uuid4()), claim_id, str(result["score"]), actor, now),
    )
    return result


# ---------------------------------------------------------------
# Letter templates (Tier 1-4 + 2.5). Placeholders are filled from claim data.
# FDCPA disclosure + payment link required on every queued letter.
# ---------------------------------------------------------------
_FDCPA = "This communication is from a debt collector attempting to collect a debt. Any information obtained will be used for that purpose."
_PAY = "Payment can be made at: https://pay.debtrecoveryexperts.com"


def _letter_template(tier: str) -> tuple[str, str]:
    """Return (subject, body) for the given tier. Body uses {placeholders}."""
    if tier == "TIER_1":
        subject = "Outstanding Balance - {debtor_name}"
        body = (
            "This is a friendly reminder regarding an outstanding balance with one of our clients.\n\n"
            "Client: {client_name}\n"
            "Amount Due: {amount_display}\n"
            "Invoice Reference: {invoice_ref}\n\n"
            "We understand things get overlooked. Please remit payment or contact us to discuss a "
            "resolution within 5 business days.\n\n"
            + _PAY + "\n\n" + _FDCPA + "\n\n"
            "- Debt Recovery Experts"
        )
    elif tier == "TIER_2":
        subject = "FORMAL DEMAND FOR PAYMENT - {debtor_name}"
        body = (
            "This letter constitutes formal demand for full payment of the outstanding balance described below.\n\n"
            "Client: {client_name}\n"
            "Amount Due: {amount_display}\n"
            "Invoice Reference: {invoice_ref}\n\n"
            "Despite previous attempts to resolve this matter amicably, the amount remains unpaid.\n\n"
            "PLEASE TAKE NOTICE that if the full balance is not received within fourteen (14) calendar days, "
            "we will proceed with escalated collection measures, including but not limited to referral to our "
            "legal department, filing of a civil suit to obtain judgment, and placement of liens against real "
            "or personal property.\n\n"
            "Contact our offices immediately to arrange payment or discuss a resolution.\n\n"
            + _PAY + "\n\n" + _FDCPA + "\n\n"
            "- Debt Recovery Experts\nCollections Department\ncollections@debtrecoveryexperts.com"
        )
    elif tier == "TIER_2_5":
        subject = "NOTICE OF INTENT TO FILE LIEN - {debtor_name}"
        body = (
            "This letter serves as formal notice of our intent to file a lien against the property described below.\n\n"
            "Client: {client_name}\n"
            "Property/Project: {debtor_address}\n"
            "Unpaid Amount: {amount_display}\n\n"
            "Texas Property Code allows for the filing of a mechanic's lien against real property where "
            "improvements were made and remain unpaid. We have been authorized to take the following actions:\n\n"
            "- Filing a Sworn Statement of Account with the county clerk\n"
            "- Recording a mechanic's lien against the property\n"
            "- Pursuing foreclosure on the lien if necessary\n\n"
            "A mechanic's lien will attach to the property title, affect your ability to sell or refinance, "
            "and appear on title searches.\n\n"
            "To avoid lien filing, full payment must be received within ten (10) calendar days.\n\n"
            + _PAY + "\n\n" + _FDCPA + "\n\n"
            "- Debt Recovery Experts\nCollections Department"
        )
    elif tier == "TIER_3":
        subject = "FINAL NOTICE - IMMEDIATE ACTION REQUIRED"
        body = (
            "FINAL NOTICE - This is your last opportunity to resolve this matter before legal action.\n\n"
            "Client: {client_name}\n"
            "Amount Due: {amount_display}\n"
            "Original Invoice Date: {invoice_date}\n\n"
            "Multiple attempts have been made to collect this debt. Despite these efforts, the full balance "
            "remains unpaid.\n\n"
            "UNLESS FULL PAYMENT IS RECEIVED WITHIN TEN (10) CALENDAR DAYS, we will refer this matter to our "
            "legal counsel, initiate civil litigation to obtain a judgment, pursue all available post-judgment "
            "remedies including wage garnishment, bank account levy, and asset seizure, and report this debt to "
            "credit reporting agencies.\n\n"
            "You may be held liable for court costs, attorney's fees, and additional interest.\n\n"
            "Contact our offices immediately. This is your final opportunity to resolve this without court "
            "intervention.\n\n"
            + _PAY + "\n\n" + _FDCPA + "\n\n"
            "- Debt Recovery Experts\nCollections Department"
        )
    else:  # TIER_4
        subject = "LEGAL ACTION - {debtor_name}"
        body = (
            "This letter confirms that your account has been referred for legal action.\n\n"
            "Client: {client_name}\n"
            "Amount Due: {amount_display}\n"
            "Legal Reference: {claim_number}\n\n"
            "Effective immediately, this matter has been forwarded to our legal counsel for lawsuit "
            "preparation. A civil petition will be filed seeking judgment for the full amount owed, "
            "pre-judgment interest as allowed by law, court costs and filing fees, and attorney's fees.\n\n"
            "Upon obtaining a judgment, we will pursue collection through all available legal channels, "
            "including wage garnishment, bank account levy, lien against real property, and post-judgment "
            "discovery of assets.\n\n"
            "All further communication regarding this matter should be directed to our legal counsel.\n\n"
            + _FDCPA + "\n\n"
            "- Debt Recovery Experts\nLegal Liaison Division"
        )
    return subject, body


def recommend_letter(*, tier: str, client_name: str, debtor_name: str,
                     amount_display: str, invoice_ref: str, claim_number: str,
                     debtor_address: str = "") -> dict:
    """Assemble the recommended letter for a claim's current tier."""
    if tier not in _letter_tier_map():
        tier = "TIER_1"
    subject, body = _letter_template(tier)
    subject = subject.format(debtor_name=debtor_name)
    body = body.format(
        debtor_name=debtor_name,
        client_name=client_name,
        amount_display=amount_display,
        invoice_ref=invoice_ref or "N/A",
        invoice_date=invoice_ref or "N/A",
        claim_number=claim_number,
        debtor_address=debtor_address or "Property address on file",
    )
    return {"subject": subject, "body": body, "tier": tier}


def _letter_tier_map() -> set[str]:
    return {"TIER_1", "TIER_2", "TIER_2_5", "TIER_3", "TIER_4"}