/**
 * Mock client — intercepts fetch calls when mock mode is enabled.
 * Replaces the real Ollama-powered API with pre-recorded scenario fixtures.
 * Pure ESM + browser-compatible (no require(), no Node-only APIs).
 */

import { buildScenarioFixture, AVAILABLE_SCENARIOS } from "@/lib/mocks/scenarios.js";

/* ── helpers ─────────────────────────────────────────────── */

function getMockFlag() {
  if (typeof window !== "undefined") return !!window.__MOCK_ENABLED;
  return process.env.NEXT_PUBLIC_CONFIDENCE_ENGINE_MOCKS === "true";
}

function getDelay() {
  var d = typeof window !== "undefined" ? window.__MOCK_DELAY : process.env.NEXT_PUBLIC_CONFIDENCE_MOCK_DELAY;
  if (d === "instant") return 0;
  if (d === "slow") return 2500;
  return 700;
}

function getScenario() {
  var s = typeof window !== "undefined" ? window.__MOCK_SCENARIO : process.env.NEXT_PUBLIC_CONFIDENCE_ENGINE_MOCK_SCENARIO;
  return s || "";
}

/* ── node / edge factories (re-exported for scenario files) ─ */

export function mkNode(id, label, opts) {
  var kind = (opts && opts.kind) || "unknown";
  var status = (opts && opts.status) || (kind === "unknown" ? "unknown" : "known");
  var confidence = (opts && opts.confidence) || "low";
  return {
    id:id, label:label, description:label, kind:kind, status:status, confidence:confidence,
    confidenceAssessment:{ evidenceConfidence:confidence, completenessStatus:"partial", conclusionConfidence:confidence },
    value:(opts && opts.value !== undefined) ? opts.value : null,
    unit:(opts && opts.unit) || null, evidenceIds:[], dependsOn:[], affects:[], childIds:[]
  };
}

export function mkEdge(id, a, b, rel) {
  var r = rel || "supports";
  return { id:id, fromNodeId:a, toNodeId:b, relationship:r, confidence:"medium", description:a+" -> "+b };
}

/* ── fixture builders ─────────────────────────────────────── */

function buildErrorFixture() {
  return { success:false, situationGraph:null, selectedQuestion:null, noQuestionReason:null, newlySurfacedNodeIds:[], error:"Mock provider error: structured response unavailable.", diagnostics:null };
}

/* ── delay shim (browser only) ──────────────────────────── */

function delay(ms) {
  return new Promise(function(r) {
    if (typeof setTimeout === "function") setTimeout(r, ms);
    else r(); // server fallback — skip wait
  });
}

/* ── case handlers ──────────────────────────────────────── */

var _turnIndex = 0;

function handleStartCase(scenario) {
  _turnIndex = 0;
  var scenarioName = getScenario();
  if (scenarioName === "error") return delay(getDelay()).then(function() {
    return Promise.resolve({ success:true, data:buildErrorFixture() });
  });
  return delay(getDelay()).then(function() {
    return Promise.resolve({ success:true, data: buildScenarioFixture(scenarioName, 0) || buildDefaultFallback(0) });
  });
}

function handleUpdateCase(data) {
  var scenarioName = getScenario();
  if (scenarioName === "error") return delay(getDelay()).then(function() {
    return Promise.resolve({ success:true, data:{ success:false, stage:"provider", error:"Mock provider error: structured response unavailable.", providerErrors:["Mock provider error: structured response unavailable."], updatedSituationGraph:null, selectedQuestion:null, affectedNodeIds:[], resolvedUnknownNodeIds:[], changesApplied:null, summary:null, diagnostics:{ promptVersion:"v0.4", modelName:"mock-ollama", responseDurationMs:0 } } });
  });
  _turnIndex++;
  return delay(getDelay()).then(function() {
    var fixture = buildScenarioFixture(scenarioName, _turnIndex);
    if (fixture) {
      return Promise.resolve({
        success:true, stage:"update_applied",
        updatedSituationGraph:fixture.situationGraph,
        selectedQuestion:fixture.selectedQuestion,
        affectedNodeIds:[],
        resolvedUnknownNodeIds:(fixture.situationGraph.resolvedNodeIds||[]).slice(),
        changesApplied:{ addedNodeCount:0, updatedNodeCount:0, addedEdgeCount:0, removedEdgeCount:0 },
        summary:fixture.situationGraph.currentSummary||null,
        diagnostics:fixture.diagnostics
      });
    }
    // Fallback to original default if scenario not found
    return Promise.resolve({ success:true, data:buildUpdateFallback(scenarioName) });
  });
}

/* ── fallback for when scenarios.js is not available ─────── */

var _fallbackTurns = [
  { nodes:[mkNode("obs-1","Complaints increased by 35%",{kind:"observation",status:"known",confidence:"high"}),mkNode("obs-2","Production increased by 40%",{kind:"observation",status:"known",confidence:"high"}),mkNode("state-1","Current situation",{kind:"state",status:"provisional",confidence:"medium"})], edges:[mkEdge("e-1","obs-1","state-1"),mkEdge("e-2","obs-2","state-1")], resolved:[], active:"u-1", question:{ nodeId:"u-1", question:"Were the complaint and production figures measured over the same period?", reason:"If different periods, comparing movement could be misleading.", reasoningPattern:"comparability_check" }, noQReason:null, summary:"Two changes have been reported, but we do not yet know whether the figures are directly comparable." },
  { nodes:[mkNode("obs-1","Complaints increased by 35%",{kind:"observation",status:"known",confidence:"high"}),mkNode("obs-2","Production increased by 40%",{kind:"observation",status:"known",confidence:"high"}),mkNode("obs-3","Both figures cover the same three-month period",{kind:"observation",status:"known",confidence:"high"}),mkNode("state-1","Current situation",{kind:"state",status:"provisional",confidence:"medium"})], edges:[mkEdge("e-1","obs-1","state-1"),mkEdge("e-2","obs-2","state-1"),mkEdge("e-3","obs-3","u-1")], resolved:["u-1"], active:"u-2", question:{ nodeId:"u-2", question:"Were both percentages calculated from comparable baseline counts?", reason:"Establishing the reference point is essential.", reasoningPattern:"baseline_comparability" }, noQReason:null, summary:"The timing basis is now clear." }
];

function buildDefaultFallback(idx) {
  var d = _fallbackTurns[Math.min(idx, _fallbackTurns.length - 1)];
  return { success:true, summary:d.summary || null, situationGraph:{ centralStatement:"Complaints increased by 35% while production increased by 40%.", currentSummary:d.summary, nodes:d.nodes, edges:d.edges, activeUnknownNodeId:d.active, resolvedNodeIds:d.resolved }, selectedQuestion:d.question||null, noQuestionReason:d.noQReason, newlySurfacedNodeIds:[], diagnostics:{ promptVersion:"v0.4", modelName:"mock-ollama", responseDurationMs:0, validationStatus:"valid", nodeCount:d.nodes.length, edgeCount:d.edges.length } };
}

function buildUpdateFallback(scenarioName) {
  var f = buildDefaultFallback(Math.min(_turnIndex, _fallbackTurns.length - 1));
  return { success:true, stage:"update_applied", updatedSituationGraph:f.situationGraph, selectedQuestion:f.selectedQuestion, affectedNodeIds:[], resolvedUnknownNodeIds:(f.situationGraph.resolvedNodeIds||[]).slice(), changesApplied:{ addedNodeCount:0, updatedNodeCount:0, addedEdgeCount:0, removedEdgeCount:0 }, summary:f.situationGraph.currentSummary||null, diagnostics:f.diagnostics };
}

/* ── public intercept function ──────────────────────────── */

export async function mockFetch(url, options) {
  if (!getMockFlag()) return fetch(url, options);

  var body = null;
  if (options && options.body) { try { body = JSON.parse(options.body); } catch(_) {} }

  if (url.indexOf("/api/cases/start") === 0 && options && options.method === "POST") {
    var r1 = await handleStartCase(body && body.scenario);
    return new Response(JSON.stringify(r1.data), { status: r1.success ? 200 : 500, headers:{ "Content-Type":"application/json" } });
  }

  if (url.indexOf("/api/cases/update") === 0 && options && options.method === "POST") {
    var r2 = await handleUpdateCase(body);
    return new Response(JSON.stringify(r2.data), { status: r2.data.success ? 200 : 500, headers:{ "Content-Type":"application/json" } });
  }

  return fetch(url, options);
}

export { AVAILABLE_SCENARIOS };