import type { FinancialStatementKind } from '@/lib/types';
import type { TaxonomyNamespaceMap, TaxonomyPresentationConcept } from '@/lib/server/taxonomy/types';

function decodeXmlEntities(value: string) {
  return value
    .replace(/&/gi, '&')
    .replace(/&lt;/gi, '<')
    .replace(/&gt;/gi, '>')
    .replace(/&quot;/gi, '"')
    .replace(/&#39;/gi, "'")
    .replace(/&#160;|&nbsp;/gi, ' ')
    .trim();
}

function parseNamespaceMap(raw: string): TaxonomyNamespaceMap {
  const map: TaxonomyNamespaceMap = {};
  const rootStart = raw.match(/<[^>]*linkbase[^>]*>/i)?.[0] ?? raw.slice(0, 1200);

  for (const match of rootStart.matchAll(/xmlns:([a-zA-Z0-9_\-]+)=["']([^"']+)["']/g)) {
    const prefix = (match[1] ?? '').trim();
    const uri = (match[2] ?? '').trim();
    if (!prefix || !uri) {
      continue;
    }

    map[prefix] = uri;
  }

  return map;
}

function qnameFromHref(href: string) {
  const fragment = href.includes('#') ? href.slice(href.indexOf('#') + 1) : href;
  if (!fragment) {
    return null;
  }

  const cleaned = fragment.trim().replace(/^loc_+/i, '');
  if (!cleaned) {
    return null;
  }

  if (cleaned.includes(':')) {
    return cleaned;
  }

  if (cleaned.includes('_')) {
    const idx = cleaned.indexOf('_');
    return `${cleaned.slice(0, idx)}:${cleaned.slice(idx + 1)}`;
  }

  return null;
}

function conceptFromQName(qname: string, namespaces: TaxonomyNamespaceMap) {
  const [prefix, ...rest] = qname.split(':');
  const localName = rest.join(':');
  if (!prefix || !localName) {
    return null;
  }

  const namespaceUri = namespaces[prefix] ?? `urn:unknown:${prefix}`;

  return {
    qname,
    namespaceUri,
    localName,
    conceptKey: `${namespaceUri}#${localName}`
  };
}

function labelPriority(role: string | null) {
  const normalized = (role ?? '').toLowerCase();
  if (!normalized) {
    return 0;
  }

  if (normalized.endsWith('/label')) {
    return 4;
  }

  if (normalized.endsWith('/terselabel')) {
    return 3;
  }

  if (normalized.endsWith('/verboselabel')) {
    return 2;
  }

  return 1;
}

export function classifyStatementRole(roleUri: string): FinancialStatementKind | null {
  const normalized = roleUri.toLowerCase();

  if (/cash\s*flow|statementsof?cashflows|netcash/.test(normalized)) {
    return 'cash_flow';
  }

  if (/shareholders?|stockholders?|equity|retainedearnings/.test(normalized)) {
    return 'equity';
  }

  if (/comprehensive\s*income/.test(normalized)) {
    return 'comprehensive_income';
  }

  if (/balance\s*sheet|financial\s*position|assets?andliabilities/.test(normalized)) {
    return 'balance';
  }

  if (/operations|income\s*statement|statementsofincome|profit/.test(normalized)) {
    return 'income';
  }

  return null;
}

export function parseLabelLinkbase(raw: string): Map<string, string> {
  const namespaces = parseNamespaceMap(raw);
  const preferredLabelByConcept = new Map<string, { text: string; priority: number }>();

  const linkPattern = /<(?:[a-z0-9_\-]+:)?labelLink\b[^>]*>([\s\S]*?)<\/(?:[a-z0-9_\-]+:)?labelLink>/gi;
  for (const linkMatch of raw.matchAll(linkPattern)) {
    const block = linkMatch[1] ?? '';
    const locByLabel = new Map<string, string>();
    const resourceByLabel = new Map<string, { text: string; role: string | null }>();

    for (const locMatch of block.matchAll(/<(?:[a-z0-9_\-]+:)?loc\b([^>]*)\/?>/gi)) {
      const attrs = locMatch[1] ?? '';
      const label = attrs.match(/\bxlink:label=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      const href = attrs.match(/\bxlink:href=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      if (!label || !href) {
        continue;
      }

      const qname = qnameFromHref(href);
      if (!qname) {
        continue;
      }

      const concept = conceptFromQName(qname, namespaces);
      if (!concept) {
        continue;
      }

      locByLabel.set(label, concept.conceptKey);
    }

    for (const resourceMatch of block.matchAll(/<(?:[a-z0-9_\-]+:)?label\b([^>]*)>([\s\S]*?)<\/(?:[a-z0-9_\-]+:)?label>/gi)) {
      const attrs = resourceMatch[1] ?? '';
      const body = decodeXmlEntities(resourceMatch[2] ?? '').replace(/\s+/g, ' ').trim();
      if (!body) {
        continue;
      }

      const resourceLabel = attrs.match(/\bxlink:label=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      const role = attrs.match(/\bxlink:role=["']([^"']+)["']/i)?.[1]?.trim() ?? null;
      if (!resourceLabel) {
        continue;
      }

      resourceByLabel.set(resourceLabel, {
        text: body,
        role
      });
    }

    for (const arcMatch of block.matchAll(/<(?:[a-z0-9_\-]+:)?labelArc\b([^>]*)\/?>/gi)) {
      const attrs = arcMatch[1] ?? '';
      const from = attrs.match(/\bxlink:from=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      const to = attrs.match(/\bxlink:to=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      if (!from || !to) {
        continue;
      }

      const conceptKey = locByLabel.get(from);
      const resource = resourceByLabel.get(to);
      if (!conceptKey || !resource) {
        continue;
      }

      const priority = labelPriority(resource.role);
      const current = preferredLabelByConcept.get(conceptKey);
      if (!current || priority > current.priority) {
        preferredLabelByConcept.set(conceptKey, {
          text: resource.text,
          priority
        });
      }
    }
  }

  return new Map(
    [...preferredLabelByConcept.entries()].map(([conceptKey, value]) => [conceptKey, value.text])
  );
}

export function parsePresentationLinkbase(raw: string): TaxonomyPresentationConcept[] {
  const namespaces = parseNamespaceMap(raw);
  const rows: TaxonomyPresentationConcept[] = [];

  const linkPattern = /<(?:[a-z0-9_\-]+:)?presentationLink\b([^>]*)>([\s\S]*?)<\/(?:[a-z0-9_\-]+:)?presentationLink>/gi;
  for (const linkMatch of raw.matchAll(linkPattern)) {
    const linkAttrs = linkMatch[1] ?? '';
    const block = linkMatch[2] ?? '';
    const roleUri = linkAttrs.match(/\bxlink:role=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
    if (!roleUri) {
      continue;
    }

    const locByLabel = new Map<string, { conceptKey: string; qname: string; isAbstract: boolean }>();
    for (const locMatch of block.matchAll(/<(?:[a-z0-9_\-]+:)?loc\b([^>]*)\/?>/gi)) {
      const attrs = locMatch[1] ?? '';
      const label = attrs.match(/\bxlink:label=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      const href = attrs.match(/\bxlink:href=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      if (!label || !href) {
        continue;
      }

      const qname = qnameFromHref(href);
      if (!qname) {
        continue;
      }

      const concept = conceptFromQName(qname, namespaces);
      if (!concept) {
        continue;
      }

      locByLabel.set(label, {
        conceptKey: concept.conceptKey,
        qname: concept.qname,
        isAbstract: /abstract/i.test(concept.localName)
      });
    }

    const childrenByLabel = new Map<string, Array<{ label: string; order: number }>>();
    const incoming = new Set<string>();
    const allReferenced = new Set<string>();

    for (const arcMatch of block.matchAll(/<(?:[a-z0-9_\-]+:)?presentationArc\b([^>]*)\/?>/gi)) {
      const attrs = arcMatch[1] ?? '';
      const from = attrs.match(/\bxlink:from=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      const to = attrs.match(/\bxlink:to=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      const orderRaw = attrs.match(/\border=["']([^"']+)["']/i)?.[1]?.trim() ?? '';
      const order = Number.parseFloat(orderRaw);

      if (!from || !to || !locByLabel.has(from) || !locByLabel.has(to)) {
        continue;
      }

      const group = childrenByLabel.get(from) ?? [];
      group.push({ label: to, order: Number.isFinite(order) ? order : group.length + 1 });
      childrenByLabel.set(from, group);

      incoming.add(to);
      allReferenced.add(from);
      allReferenced.add(to);
    }

    const roots = [...allReferenced].filter((label) => !incoming.has(label));
    const visited = new Set<string>();

    function dfs(label: string, depth: number, parentLabel: string | null, baseOrder: number) {
      const node = locByLabel.get(label);
      if (!node) {
        return;
      }

      const pathKey = `${parentLabel ?? 'root'}::${label}::${depth}`;
      if (visited.has(pathKey)) {
        return;
      }
      visited.add(pathKey);

      const parentConceptKey = parentLabel ? (locByLabel.get(parentLabel)?.conceptKey ?? null) : null;
      rows.push({
        conceptKey: node.conceptKey,
        qname: node.qname,
        roleUri,
        order: baseOrder,
        depth,
        parentConceptKey,
        isAbstract: node.isAbstract
      });

      const children = [...(childrenByLabel.get(label) ?? [])].sort((left, right) => left.order - right.order);
      for (let i = 0; i < children.length; i += 1) {
        const child = children[i];
        if (!child) {
          continue;
        }

        dfs(child.label, depth + 1, label, baseOrder + (i + 1) / 1000);
      }
    }

    for (let i = 0; i < roots.length; i += 1) {
      const root = roots[i];
      if (!root) {
        continue;
      }

      dfs(root, 0, null, i + 1);
    }
  }

  return rows;
}