Lab II — enterprise claims
& the audit-chain kata

'use strict';
const { Contract } = require('fabric-contract-api');

const STATES = ['FNOL', 'ASSESSING', 'APPROVED', 'PAID', 'REPUDIATED'];
const NEXT = { FNOL: ['ASSESSING'], ASSESSING: ['APPROVED','REPUDIATED'], APPROVED: ['PAID'] };

class ClaimsContract extends Contract {

  async RegisterClaim(ctx, claimId, policyId, amountPhp) {
    const exists = await ctx.stub.getState(claimId);
    if (exists && exists.length) throw new Error(`claim ${claimId} exists`);
    const claim = {
      claimId, policyId,
      amountPhp: parseInt(amountPhp, 10),
      state: 'FNOL',
      handler: ctx.clientIdentity.getMSPID(),   // org that registered it
      history: [{ at: ctx.stub.getTxTimestamp().seconds.low, to: 'FNOL' }]
    };
    await ctx.stub.putState(claimId, Buffer.from(JSON.stringify(claim)));
    ctx.stub.setEvent('ClaimRegistered', Buffer.from(claimId));
    return JSON.stringify(claim);
  }

  async Transition(ctx, claimId, toState) {
    const raw = await ctx.stub.getState(claimId);
    if (!raw || !raw.length) throw new Error(`no claim ${claimId}`);
    const claim = JSON.parse(raw.toString());

    // 1 · state machine guard (compare Fig 4.1/4.2 — lifecycle as law)
    const allowed = NEXT[claim.state] || [];
    if (!allowed.includes(toState))
      throw new Error(`illegal ${claim.state} → ${toState}`);

    // 2 · role guard: only the handling insurer drives its own claims
    const caller = ctx.clientIdentity.getMSPID();
    if (caller !== claim.handler && caller !== 'ReinsurerRMSP')
      throw new Error(`${caller} may not act on this claim`);

    claim.state = toState;
    claim.history.push({ at: ctx.stub.getTxTimestamp().seconds.low, to: toState, by: caller });
    await ctx.stub.putState(claimId, Buffer.from(JSON.stringify(claim)));
    ctx.stub.setEvent('ClaimTransition', Buffer.from(claimId + '→' + toState));
    return JSON.stringify(claim);
  }

  async GetClaim(ctx, claimId) {
    const raw = await ctx.stub.getState(claimId);
    if (!raw || !raw.length) throw new Error(`no claim ${claimId}`);
    return raw.toString();
  }
}
module.exports = ClaimsContract;