api/main.py

"""
main.py
-------
Phase 3 Section 5 — FastAPI dashboard for RingGuard.

Endpoints:
  GET /                  — HTML dashboard: table of all cases
  GET /cases             — JSON list of all cases (from cases_demo.json)
  GET /cases/{case_id}   — JSON detail for one case + full audit chain
  GET /health            — health check

The dashboard reads directly from cases_demo.json and audit_log.jsonl.
No database, no auth — demo only.

Usage:
    uvicorn api.main:app --reload --port 7860
"""

import json
import os
from typing import Optional

from fastapi import FastAPI, HTTPException
from fastapi.responses import HTMLResponse, JSONResponse

BASE_DIR    = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
CASES_PATH  = os.path.join(BASE_DIR, "data", "synthetic", "cases_demo.json")
AUDIT_PATH  = os.path.join(BASE_DIR, "audit", "audit_log.jsonl")

app = FastAPI(
    title="RingGuard Dashboard",
    description="Phase 3 — Fraud ring detection results and audit trail",
    version="3.0.0",
)


# ---------------------------------------------------------------------------
# Data loaders
# ---------------------------------------------------------------------------

def _load_cases() -> list:
    if not os.path.exists(CASES_PATH):
        return []
    with open(CASES_PATH, encoding="utf-8") as f:
        return json.load(f)


def _load_audit() -> list:
    if not os.path.exists(AUDIT_PATH):
        return []
    records = []
    with open(AUDIT_PATH, encoding="utf-8") as f:
        for line in f:
            line = line.strip()
            if line:
                records.append(json.loads(line))
    return records


# ---------------------------------------------------------------------------
# API endpoints
# ---------------------------------------------------------------------------

@app.get("/health")
def health():
    return {"status": "ok", "version": "3.0.0"}


@app.get("/cases", response_class=JSONResponse)
def get_cases():
    """Return all cases as a JSON list."""
    cases = _load_cases()
    audit_all = _load_audit()
    # Build a lookup: case_id -> first audit record
    audit_map = {}
    for r in audit_all:
        cid = r.get("case_id")
        if cid and cid not in audit_map:
            audit_map[cid] = r
    # Return a summary view (without full narrative for list)
    summary = []
    for c in cases:
        case_id = c.get("case_id")
        # Prefer action_taken from audit record when case has null
        action = c.get("action_taken") or audit_map.get(case_id, {}).get("action_taken") or {}
        summary.append({
            "case_id":        case_id,
            "cluster_id":     c.get("cluster_id"),
            "cluster_size":   len(c.get("customer_ids", [])),
            "risk_score":     round(c.get("risk_probability", 0), 4),
            "policy_decision": c.get("policy_decision"),
            "action_taken":   bool(action.get("order_id")),
            "timestamp":      c.get("timestamp"),
        })
    return summary


@app.get("/cases/{case_id}", response_class=JSONResponse)
def get_case_detail(case_id: str):
    """Return full detail for one case, including audit chain."""
    cases = _load_cases()
    case = next((c for c in cases if c.get("case_id") == case_id), None)
    if not case:
        raise HTTPException(status_code=404, detail=f"Case {case_id} not found")

    # Find audit records for this case
    audit_records = [r for r in _load_audit() if r.get("case_id") == case_id]

    return {
        "case": case,
        "audit_chain": audit_records,
    }


# ---------------------------------------------------------------------------
# HTML dashboard
# ---------------------------------------------------------------------------

def _decision_badge(decision: str) -> str:
    colours = {
        "auto_hold": "#c0392b",
        "escalate":  "#e67e22",
        "log_only":  "#27ae60",
    }
    colour = colours.get(decision, "#7f8c8d")
    return (
        f'<span style="background:{colour};color:#fff;padding:2px 8px;'
        f'border-radius:4px;font-size:11px;font-weight:600;">'
        f'{decision.upper()}</span>'
    )


def _build_dashboard(cases: list, audit_map: dict = None) -> str:
    if audit_map is None:
        audit_map = {}
    rows = ""
    for c in cases:
        decision = c.get("policy_decision", "")
        badge    = _decision_badge(decision)
        risk     = round(c.get("risk_probability", 0) * 100, 1)
        cluster  = c.get("cluster_id", "")
        case_id  = c.get("case_id", "")
        size     = len(c.get("customer_ids", []))
        # Prefer action_taken from audit record when case JSON has null
        action   = c.get("action_taken") or audit_map.get(case_id, {}).get("action_taken") or {}
        order_id = action.get("order_id") or "—"
        verified_val = action.get("notes_verified")
        if verified_val is True:
            verified = '<span style="color:#27ae60;font-weight:600">✓ Yes</span>'
        elif action:
            verified = '<span style="color:#c0392b">No</span>'
        else:
            verified = "—"

        rows += (
            f'<tr onclick="window.location=\'/cases/{case_id}/detail\'" style="cursor:pointer">'
            f'<td><a href="/cases/{case_id}/detail" style="color:#1f2328;font-weight:500">{case_id}</a></td>'
            f'<td style="color:#57606a">{cluster}</td>'
            f'<td style="text-align:center">{size}</td>'
            f'<td style="text-align:right;font-weight:600">{risk}%</td>'
            f'<td>{badge}</td>'
            f'<td style="font-size:11px;font-family:monospace;color:#57606a">{order_id}</td>'
            f'<td style="text-align:center">{verified}</td>'
            f'</tr>\n'
        )

    auto_holds = sum(1 for c in cases if c.get("policy_decision") == "auto_hold")
    escalates  = sum(1 for c in cases if c.get("policy_decision") == "escalate")
    log_only   = sum(1 for c in cases if c.get("policy_decision") == "log_only")

    return f"""<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>RingGuard — Fraud Detection Dashboard</title>
<style>
  * {{ box-sizing: border-box; margin: 0; padding: 0; }}
  body {{ font-family: -apple-system, "Segoe UI", system-ui, sans-serif;
         font-size: 14px; line-height: 1.6; background: #f7f8fa; color: #1f2328; }}
  .container {{ max-width: 960px; margin: 0 auto; padding: 24px 16px; }}
  h1 {{ font-size: 22px; font-weight: 700; margin-bottom: 4px; }}
  .subtitle {{ color: #57606a; font-size: 13px; margin-bottom: 24px; }}
  .stats {{ display: flex; gap: 16px; margin-bottom: 24px; flex-wrap: wrap; }}
  .stat-card {{ background: #fff; border: 1px solid #e5e7eb; border-radius: 6px;
               padding: 12px 20px; flex: 1; min-width: 140px; }}
  .stat-card .label {{ font-size: 11px; color: #57606a; text-transform: uppercase;
                       letter-spacing: 0.05em; }}
  .stat-card .value {{ font-size: 24px; font-weight: 700; }}
  .stat-card.hold .value {{ color: #c0392b; }}
  .stat-card.escalate .value {{ color: #e67e22; }}
  .stat-card.log .value {{ color: #27ae60; }}
  table {{ width: 100%; border-collapse: collapse; background: #fff;
           border: 1px solid #e5e7eb; border-radius: 6px; overflow: hidden; }}
  th {{ background: #f7f8fa; border-bottom: 2px solid #e5e7eb; padding: 8px 12px;
       text-align: left; font-size: 12px; font-weight: 600; color: #57606a;
       text-transform: uppercase; letter-spacing: 0.04em; }}
  td {{ padding: 8px 12px; border-bottom: 1px solid #f0f0f0; vertical-align: middle; }}
  tr:last-child td {{ border-bottom: none; }}
  tr:hover td {{ background: #f7f8fa; }}
  .footer {{ text-align: center; font-size: 12px; color: #57606a; margin-top: 32px;
            padding-top: 16px; border-top: 1px solid #e5e7eb; }}
  a {{ color: #3b82d4; text-decoration: none; }}
  a:hover {{ text-decoration: underline; }}
</style>
</head>
<body>
<div class="container">
  <h1>RingGuard — Fraud Detection Dashboard</h1>
  <p class="subtitle">Phase 3 · {len(cases)} cases · LightGBM + LangGraph + Razorpay test-mode</p>

  <div class="stats">
    <div class="stat-card hold">
      <div class="label">Auto Hold</div>
      <div class="value">{auto_holds}</div>
    </div>
    <div class="stat-card escalate">
      <div class="label">Escalate</div>
      <div class="value">{escalates}</div>
    </div>
    <div class="stat-card log">
      <div class="label">Log Only</div>
      <div class="value">{log_only}</div>
    </div>
    <div class="stat-card">
      <div class="label">Total Cases</div>
      <div class="value">{len(cases)}</div>
    </div>
  </div>

  <table>
    <thead>
      <tr>
        <th>Case</th>
        <th>Cluster</th>
        <th style="text-align:center">Size</th>
        <th style="text-align:right">Risk Score</th>
        <th>Decision</th>
        <th>Razorpay Order</th>
        <th style="text-align:center">Verified</th>
      </tr>
    </thead>
    <tbody>
{rows}    </tbody>
  </table>

  <p style="margin-top:12px;font-size:12px;color:#57606a">
    Click any row to view the full evidence bundle, LLM narrative, and audit chain.
  </p>

  <div class="footer">Built by <a href="https://github.com/rohitdecodes" target="_blank">Rohit</a> &middot; RingGuard v3.0</div>
</div>
</body>
</html>"""


@app.get("/", response_class=HTMLResponse)
def dashboard():
    """Serve the HTML dashboard."""
    cases     = _load_cases()
    audit_all = _load_audit()
    audit_map = {}
    for r in audit_all:
        cid = r.get("case_id")
        if cid and cid not in audit_map:
            audit_map[cid] = r
    html = _build_dashboard(cases, audit_map)
    return HTMLResponse(content=html)


def _build_cluster_svg(customer_ids: list, strong_link_count: int, weak_link_count: int,
                       formation_type: str, decision: str) -> str:
    """
    Build a simple SVG diagram of the cluster:
    - One circle per customer, arranged in a ring layout
    - Red lines for strong links (shared device/instrument), grey dashed for weak (address)
    - Node colour reflects decision
    """
    import math

    n = len(customer_ids)
    if n == 0:
        return ""

    W, H = 420, 260
    cx, cy = W // 2, H // 2
    r = min(cx, cy) - 44

    node_colour = {
        "auto_hold": "#c0392b",
        "escalate":  "#e67e22",
        "log_only":  "#27ae60",
    }.get(decision, "#7c5cd8")

    # Place nodes on a circle; single node goes centre
    angles = [2 * math.pi * i / n - math.pi / 2 for i in range(n)]
    positions = [(cx + r * math.cos(a), cy + r * math.sin(a)) for a in angles] if n > 1 else [(cx, cy)]

    lines = []
    # Strong edges between every pair (fully connected if strong_link_count == n*(n-1)/2)
    # For simplicity: draw strong edges between consecutive nodes to represent links
    # Real topology is cluster-wide; we show it proportionally
    total_possible = n * (n - 1) // 2 if n > 1 else 0
    drawn_strong = 0
    drawn_weak   = 0
    if total_possible > 0:
        for i in range(n):
            for j in range(i + 1, n):
                x1, y1 = positions[i]
                x2, y2 = positions[j]
                if drawn_strong < strong_link_count:
                    lines.append(
                        f'<line x1="{x1:.1f}" y1="{y1:.1f}" x2="{x2:.1f}" y2="{y2:.1f}" '
                        f'stroke="#c0392b" stroke-width="2" opacity="0.7"/>'
                    )
                    drawn_strong += 1
                elif drawn_weak < weak_link_count:
                    lines.append(
                        f'<line x1="{x1:.1f}" y1="{y1:.1f}" x2="{x2:.1f}" y2="{y2:.1f}" '
                        f'stroke="#adb5bd" stroke-width="1.5" stroke-dasharray="5,3" opacity="0.6"/>'
                    )
                    drawn_weak += 1

    nodes = []
    for i, (px, py) in enumerate(positions):
        label = customer_ids[i].replace("CUST", "C")
        nodes.append(
            f'<circle cx="{px:.1f}" cy="{py:.1f}" r="20" fill="{node_colour}" '
            f'stroke="#fff" stroke-width="2" opacity="0.92"/>'
            f'<text x="{px:.1f}" y="{py + 4:.1f}" text-anchor="middle" '
            f'font-size="9" fill="#fff" font-family="system-ui,sans-serif" font-weight="600">'
            f'{label}</text>'
        )

    legend = (
        f'<rect x="12" y="{H-38}" width="10" height="3" fill="#c0392b" rx="1"/>'
        f'<text x="26" y="{H-32}" font-size="10" fill="#57606a" font-family="system-ui,sans-serif">'
        f'Strong link (device/instrument)</text>'
        f'<line x1="12" y1="{H-22}" x2="22" y2="{H-22}" stroke="#adb5bd" '
        f'stroke-width="1.5" stroke-dasharray="4,2"/>'
        f'<text x="26" y="{H-18}" font-size="10" fill="#57606a" font-family="system-ui,sans-serif">'
        f'Weak link (address)</text>'
    )

    formation_label = formation_type.replace("_", " ").title() if formation_type else ""
    svg = (
        f'<svg width="{W}" height="{H}" viewBox="0 0 {W} {H}" '
        f'xmlns="http://www.w3.org/2000/svg" style="max-width:100%;height:auto;">'
        f'{"".join(lines)}'
        f'{"".join(nodes)}'
        f'<text x="{W//2}" y="16" text-anchor="middle" font-size="11" '
        f'fill="#57606a" font-family="system-ui,sans-serif">{formation_label} · '
        f'{strong_link_count} strong · {weak_link_count} weak</text>'
        f'{legend}'
        f'</svg>'
    )
    return svg


@app.get("/cases/{case_id}/detail", response_class=HTMLResponse)
def case_detail_html(case_id: str):
    """Serve HTML detail page for a single case."""
    cases = _load_cases()
    case  = next((c for c in cases if c.get("case_id") == case_id), None)
    if not case:
        raise HTTPException(status_code=404, detail=f"Case {case_id} not found")

    audit_records = [r for r in _load_audit() if r.get("case_id") == case_id]

    decision   = case.get("policy_decision", "")
    badge      = _decision_badge(decision)
    risk       = round(case.get("risk_probability", 0) * 100, 2)
    # Prefer audit narrative/confidence when case JSON has null
    audit_rec0     = audit_records[0] if audit_records else {}
    narrative  = (case.get("llm_narrative") or audit_rec0.get("llm_narrative")
                  or "<em>No narrative available for this case.</em>")
    confidence = (case.get("llm_confidence_statement") or
                  audit_rec0.get("llm_confidence_statement") or "—")
    members    = ", ".join(case.get("customer_ids", []))

    # Prefer action_taken from audit record when case JSON has null
    action    = case.get("action_taken") or audit_rec0.get("action_taken") or {}
    order_id  = action.get("order_id") or "—"
    verified  = "Yes" if action.get("notes_verified") else "No"
    tool_used = action.get("tool") or "—"
    timestamp = action.get("timestamp") or "—"

    # Pull graph score inputs from audit record for the cluster diagram
    audit_rec       = audit_rec0
    score_inputs    = audit_rec.get("graph_score_inputs", {})
    strong_links    = int(score_inputs.get("strong_link_count", case.get("strong_link_count", 0)))
    weak_links      = int(score_inputs.get("weak_link_count",   case.get("weak_link_count",   0)))
    # Resolve formation type label from strong_link_count
    formation_label = "strong_anchored" if strong_links > 0 else "weak_only"
    cluster_svg     = _build_cluster_svg(
        case.get("customer_ids", []), strong_links, weak_links, formation_label, decision
    )

    # Feature table rows from audit
    feature_keys = [
        ("order_count", "Order Count"), ("total_amount", "Total Amount (Rs.)"),
        ("avg_order_amount", "Avg Order Amount (Rs.)"), ("return_rate", "Return Rate"),
        ("chargeback_rate", "Chargeback Rate"), ("shared_coupon_count", "Shared Coupons"),
        ("order_velocity", "Order Velocity (orders/day)"), ("time_span_days", "Time Span (days)"),
    ]
    feature_rows_html = ""
    if score_inputs:
        for key, label in feature_keys:
            val = score_inputs.get(key)
            if val is not None:
                if isinstance(val, float):
                    display = f"{val:.3f}" if val < 100 else f"{val:,.0f}"
                else:
                    display = str(val)
                feature_rows_html += f'<tr><td style="color:#57606a">{label}</td><td style="font-weight:500">{display}</td></tr>'

    audit_rows_html = ""
    for rec in audit_records:
        ts = rec.get("timestamp", "")[:19].replace("T", " ")
        audit_rows_html += (
            f'<tr>'
            f'<td>{ts}</td>'
            f'<td>{rec.get("policy_decision","")}</td>'
            f'<td style="font-size:11px">{rec.get("reason_if_not_auto_actioned") or "—"}</td>'
            f'</tr>\n'
        )

    html = f"""<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>RingGuard — {case_id}</title>
<style>
  * {{ box-sizing: border-box; margin: 0; padding: 0; }}
  body {{ font-family: -apple-system, "Segoe UI", system-ui, sans-serif;
         font-size: 14px; line-height: 1.6; background: #f7f8fa; color: #1f2328; }}
  .container {{ max-width: 800px; margin: 0 auto; padding: 24px 16px; }}
  h1 {{ font-size: 20px; font-weight: 700; margin-bottom: 4px; }}
  .back {{ font-size: 13px; color: #3b82d4; margin-bottom: 16px; display: block; }}
  .card {{ background: #fff; border: 1px solid #e5e7eb; border-radius: 6px;
           padding: 16px; margin-bottom: 16px; }}
  .card h2 {{ font-size: 12px; font-weight: 600; color: #57606a; text-transform: uppercase;
              letter-spacing: 0.06em; margin-bottom: 10px; border-bottom: 1px solid #f0f0f0;
              padding-bottom: 6px; }}
  .row {{ display: flex; gap: 24px; margin-bottom: 6px; flex-wrap: wrap; }}
  .kv {{ flex: 1; min-width: 160px; }}
  .kv .k {{ font-size: 11px; color: #57606a; margin-bottom: 2px; }}
  .kv .v {{ font-weight: 500; }}
  .narrative {{ background: #f7f8fa; border-left: 3px solid #3b82d4;
               padding: 10px 14px; border-radius: 0 4px 4px 0; font-style: italic;
               line-height: 1.7; }}
  .graph-wrap {{ display: flex; justify-content: center; padding: 8px 0 4px; }}
  table {{ width: 100%; border-collapse: collapse; }}
  th {{ text-align: left; font-size: 11px; color: #57606a; padding: 5px 8px;
        border-bottom: 1px solid #e5e7eb; text-transform: uppercase; letter-spacing: 0.04em; }}
  td {{ padding: 5px 8px; border-bottom: 1px solid #f0f0f0; font-size: 13px; }}
  tr:last-child td {{ border-bottom: none; }}
  .footer {{ text-align: center; font-size: 12px; color: #57606a; margin-top: 32px;
            padding-top: 16px; border-top: 1px solid #e5e7eb; }}
  span.badge {{ display: inline-block; }}
</style>
</head>
<body>
<div class="container">
  <a class="back" href="/">&#8592; Back to all cases</a>
  <h1>{case_id} &mdash; {case.get("cluster_id","")}</h1>

  <div class="card">
    <h2>Summary</h2>
    <div class="row">
      <div class="kv"><div class="k">Risk Score</div><div class="v">{risk}%</div></div>
      <div class="kv"><div class="k">Decision</div><div class="v">{badge}</div></div>
      <div class="kv"><div class="k">Cluster Size</div><div class="v">{len(case.get("customer_ids",[]))} accounts</div></div>
      <div class="kv"><div class="k">Formation</div><div class="v">{formation_label.replace("_"," ")}</div></div>
    </div>
    <div style="margin-top:6px;font-size:12px;color:#57606a">
      <strong>Members:</strong> {members}
    </div>
  </div>

  <div class="card">
    <h2>Cluster Graph</h2>
    <div class="graph-wrap">{cluster_svg}</div>
  </div>

  <div class="card">
    <h2>Evidence — Key Features</h2>
    {f'<table><tbody>{feature_rows_html}</tbody></table>' if feature_rows_html else '<p style="color:#57606a;font-size:13px">No feature data available.</p>'}
  </div>

  <div class="card">
    <h2>LLM Investigator Narrative</h2>
    <div class="narrative">{narrative}</div>
    <div style="margin-top:8px;font-size:12px;color:#57606a">
      <strong>Confidence:</strong> {confidence}
    </div>
  </div>

  <div class="card">
    <h2>Razorpay Action (Test Mode)</h2>
    <div class="row">
      <div class="kv"><div class="k">Order ID</div><div class="v" style="font-size:12px;font-family:monospace">{order_id}</div></div>
      <div class="kv"><div class="k">Notes Verified</div><div class="v">{verified}</div></div>
    </div>
    <div class="row" style="margin-top:4px">
      <div class="kv"><div class="k">Tool Used</div><div class="v" style="font-size:11px">{tool_used}</div></div>
      <div class="kv"><div class="k">Timestamp</div><div class="v" style="font-size:12px">{timestamp[:19] if len(timestamp)>=19 else timestamp}</div></div>
    </div>
  </div>

  <div class="card">
    <h2>Audit Chain</h2>
    {f'<table><thead><tr><th>Timestamp</th><th>Decision</th><th>Reason</th></tr></thead><tbody>{audit_rows_html}</tbody></table>' if audit_rows_html else '<p style="color:#57606a;font-size:13px">No audit records found for this case.</p>'}
  </div>

  <div class="footer">Built by <a href="https://github.com/rohitdecodes" target="_blank">Rohit</a> &middot; RingGuard v3.0</div>
</div>
</body>
</html>"""
    return HTMLResponse(content=html)