/**
 * Deterministic situation graph builder — builds initial graph from scenario text.
 * Takes v0.2/v0.3 analysis output (from analyseScenario) and constructs a SituationGraph.
 */

import {
  situationNodeSchema,
  situationEdgeSchema,
  makeNodeId,
} from "./schema.js";

/**
 * Build an initial situation graph from a v0.3 reconstruction result.
 * @param {{ reconstruction: object, evidence: object[] | undefined }} analysisData
 * @returns {{ nodes: import("./schema.js").SituationNode[], edges: import("./schema.js").SituationEdge[] }}
 */
export function buildInitialGraph(analysisData) {
  const { reconstruction, evidence = [] } = analysisData;

  if (!reconstruction || !reconstruction.summary) {
    return { nodes: [], edges: [] };
  }

  const nodeMap = new Map(); // label -> node
  const sourceIdToNodeId = new Map();

  function mapSourceId(sourceId, node) {
    if (sourceId) sourceIdToNodeId.set(sourceId, node.id);
    return node;
  }

  // ── Helper: register or get a node by label ────────────

  function ensureNode(
    label,
    kind,
    status,
    description,
    value,
    unit,
    confidence,
  ) {
    if (nodeMap.has(label)) return nodeMap.get(label);

    const id = makeNodeId(label);
    const node = situationNodeSchema.parse({
      id,
      label,
      description: description ?? label,
      kind,
      status,
      confidence,
      value: value ?? null,
      unit: unit ?? null,
      evidenceIds: [],
      dependsOn: [],
      affects: [],
      parentId: null,
      childIds: [],
    });
    nodeMap.set(label, node);
    return node;
  }

  // ── Evidence lookup ────────────────────────────────────

  const evidenceMap = new Map();
  for (const ev of evidence) {
    if (ev.id) evidenceMap.set(ev.id, ev);
  }

  function addEvidenceToNode(nodeId, evidenceId) {
    const node = Object.values(nodeMap).find((n) => n.id === nodeId);
    if (node && !node.evidenceIds.includes(evidenceId)) {
      node.evidenceIds.push(evidenceId);
    }
  }

  // ── Extract observed states as nodes ────────────────────

  const summaryNode = ensureNode(
    reconstruction.summary || "Situation Summary",
    "state",
    "provisional",
    "Summary of the situation from the scenario text",
    null,
    null,
    "medium",
  );

  // Collect all observable quantities as metric nodes
  const metrics = new Map();

  if (reconstruction.observedStates) {
    for (const obs of reconstruction.observedStates) {
      const node = ensureNode(
        obs.description || obs.label,
        "observation",
        "supported",
        obs.description || obs.label,
        null,
        null,
        obs.confidence || "medium",
      );

      if (obs.id) {
        node.evidenceIds.push(obs.id);
        mapSourceId(obs.id, node);
      }
    }
  }

  // Actors as states/nodes
  if (reconstruction.actors) {
    for (const actor of reconstruction.actors) {
      mapSourceId(actor.id, ensureNode(
        actor.description || actor.label,
        "observation",
        "supported",
        actor.description || actor.label,
        null,
        null,
        actor.confidence || "medium",
      ));
    }
  }

  if (reconstruction.systemsOrObjects) {
    for (const sys of reconstruction.systemsOrObjects) {
      mapSourceId(sys.id, ensureNode(
        sys.description || sys.label,
        "metric",
        "known",
        sys.description || sys.label,
        null,
        null,
        sys.confidence || "medium",
      ));
    }
  }

  // Differences as relationship nodes
  if (reconstruction.differences) {
    for (const diff of reconstruction.differences) {
      const node = ensureNode(
        diff.description || "Difference",
        "relationship",
        "supported",
        diff.description || "Difference",
        null,
        null,
        diff.confidence || "medium",
      );
      mapSourceId(diff.id, node);
    }
  }

  // Contradictions as nodes
  if (reconstruction.contradictions) {
    for (const c of reconstruction.contradictions) {
      const node = ensureNode(
        c.description || c.label,
        "relationship",
        "supported",
        c.description || c.label,
        null,
        null,
        c.confidence || "medium",
      );
      mapSourceId(c.id, node);
    }
  }

  // Important unknowns as unknown nodes
  const unknownNodes = [];
  if (reconstruction.importantUnknowns) {
    for (const unk of reconstruction.importantUnknowns) {
      const node = ensureNode(
        unk.description || unk.label,
        "unknown",
        "unknown",
        unk.description || "Unknown factor in the situation",
        null,
        null,
        unk.confidence || "low",
      );
      mapSourceId(unk.id, node);
      unknownNodes.push(node);
    }
  }

  // Plausible interpretations
  if (reconstruction.plausibleInterpretations) {
    for (const interp of reconstruction.plausibleInterpretations) {
      mapSourceId(interp.id, ensureNode(
        interp.description || interp.label,
        "assumption",
        "provisional",
        interp.description || "Plausible interpretation",
        null,
        null,
        interp.confidence || "low",
      ));
    }
  }

  // Unexplained transitions remain unresolved transition nodes
  if (reconstruction.unexplainedTransitions) {
    for (const trans of reconstruction.unexplainedTransitions) {
      const label =
        trans.description ||
        `${trans.entity ?? "Unexplained transition"}: ${trans.previousState ?? "unknown"} → ${trans.currentState ?? "unknown"}`;
      mapSourceId(trans.id, ensureNode(
        label,
        "transition",
        "unknown",
        trans.description || label,
        null,
        null,
        trans.confidence || "low",
      ));
    }
  }

  // Known transitions
  if (reconstruction.knownTransitions) {
    for (const trans of reconstruction.knownTransitions) {
      mapSourceId(trans.id, ensureNode(
        `${trans.entity}: ${trans.previousState} → ${trans.currentState}`,
        "transition",
        trans.explanationStatus === "confirmed" ? "known" : "provisional",
        trans.description ||
          `Transition: ${trans.entity} from ${trans.previousState} to ${trans.currentState}`,
        null,
        null,
        trans.confidence || "medium",
      ));
    }
  }

  // ── Build edges between nodes ────────────────────────

  const nodeArr = Array.from(nodeMap.values());
  const edges = [];

  // Link actors → observed states as measures relationships
  let actorNodes = [];
  let metricNodes = [];
  let unknownNodeIds = [];

  for (const n of nodeArr) {
    if (n.kind === "observation" && n.status === "supported") {
      // These are observations — link to summary
      edges.push(
        situationEdgeSchema.parse({
          id: `e-sum-${n.id}`,
          fromNodeId: n.id,
          toNodeId: summaryNode.id,
          relationship: "supports",
          confidence: n.confidence || "medium",
          description: `${n.label} supports the summary`,
        }),
      );
    }
    if (n.kind === "unknown") {
      unknownNodeIds.push(n.id);
      edges.push(
        situationEdgeSchema.parse({
          id: `e-unk-${n.id}`,
          fromNodeId: n.id,
          toNodeId: summaryNode.id,
          relationship: "depends_on",
          confidence: n.confidence || "low",
          description: `${n.label} is an unresolved factor for this situation`,
        }),
      );
    }
  }

  const edgeIds = new Set(edges.map((edge) => edge.id));
  for (const relationship of reconstruction.relationships ?? []) {
    const fromNodeId = sourceIdToNodeId.get(relationship.fromId);
    const toNodeId = sourceIdToNodeId.get(relationship.toId);
    const id = `e-rel-${relationship.id}`;

    if (!fromNodeId || !toNodeId || edgeIds.has(id)) continue;

    edges.push(
      situationEdgeSchema.parse({
        id,
        fromNodeId,
        toNodeId,
        relationship: relationship.relationship,
        confidence: relationship.confidence,
        description: relationship.description,
      }),
    );
    edgeIds.add(id);
  }

  return { nodes: nodeArr, edges };
}

/**
 * Build a minimal starting graph for any scenario.
 * Used when analysis has no reconstruction data (e.g., error state).
 */
export function buildMinimalGraph(scenario) {
  const shortLabel = scenario.slice(0, 80);

  return {
    nodes: [
      situationNodeSchema.parse({
        id: "n0",
        label: shortLabel,
        description: `Initial situation from: "${scenario.slice(0, 200)}"`,
        kind: "state",
        status: "provisional",
        confidence: "low",
        value: null,
        unit: null,
        evidenceIds: [],
        dependsOn: [],
        affects: [],
        parentId: null,
        childIds: [],
      }),
    ],
    edges: [],
  };
}

/**
 * Convert graph nodes/edges to a human-readable summary for display.
 */
export function describeGraph(graph) {
  const parts = [];

  // Count by kind
  const byKind = {};
  for (const n of graph.nodes) {
    byKind[n.kind] = (byKind[n.kind] || 0) + 1;
  }

  parts.push(
    `Nodes: ${Object.entries(byKind)
      .map(([k, v]) => `${v} ${k}`)
      .join(", ")}`,
  );
  parts.push(`Edges: ${graph.edges.length} total`);
  parts.push(
    `Unknowns: ${graph.nodes.filter((n) => n.status === "unknown").length} unresolved`,
  );

  return parts.join(" | ");
}