#!/usr/bin/env node
/*
 * Generate a Mermaid UML class diagram from the synced LinkML schemas.
 *
 * Output: frontend/public/data/heritage_custodian_ontology.mmd
 *
 * The Visualize page loads this file from /data/heritage_custodian_ontology.mmd.
 */

const fs = require('fs');
const path = require('path');

const SCHEMA_DIR = path.join(__dirname, '../public/schemas/20251121/linkml');
const MANIFEST_PATH = path.join(SCHEMA_DIR, 'manifest.json');
const OUTPUT_PATH = path.join(__dirname, '../public/data/heritage_custodian_ontology.mmd');

function readJson(p) {
  return JSON.parse(fs.readFileSync(p, 'utf8'));
}

function readText(p) {
  return fs.readFileSync(p, 'utf8');
}

function ensureDir(p) {
  const dir = path.dirname(p);
  if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
}

function safeArray(v) {
  return Array.isArray(v) ? v : [];
}

function indentOf(line) {
  const m = line.match(/^ */);
  return m ? m[0].length : 0;
}

function isBlankOrComment(line) {
  const t = line.trim();
  return t === '' || t.startsWith('#');
}

function stripInlineComment(v) {
  // Conservative: only strip comments when preceded by whitespace.
  // This avoids clobbering URLs like http://example.com#fragment.
  return v.replace(/\s+#.*$/, '').trim();
}

function stripQuotes(v) {
  const s = v.trim();
  if ((s.startsWith('"') && s.endsWith('"')) || (s.startsWith("'") && s.endsWith("'"))) {
    return s.slice(1, -1);
  }
  return s;
}

function collectIndentedBlock(lines, startIndex, startIndent) {
  const block = [lines[startIndex]];
  for (let i = startIndex + 1; i < lines.length; i++) {
    const line = lines[i];
    if (isBlankOrComment(line)) {
      block.push(line);
      continue;
    }

    const ind = indentOf(line);
    if (ind <= startIndent) break;
    block.push(line);
  }
  return block;
}

function findScalarInBlock(blockLines, key, minIndent) {
  // Returns a single-line scalar value for `${key}: value`.
  // Ignores folded/literal multi-line scalars (>- / |).
  for (const line of blockLines) {
    if (isBlankOrComment(line)) continue;
    if (indentOf(line) < minIndent) continue;
    const m = line.match(new RegExp(`^\\s*${key}:\\s*(.+)\\s*$`));
    if (!m) continue;
    const raw = stripInlineComment(m[1]);
    if (raw === '' || raw === '|' || raw === '>-') continue;
    return stripQuotes(raw);
  }
  return null;
}

function findListInBlock(blockLines, key, minIndent) {
  // Parses:
  //   key:
  //     - item
  //     - item2
  const out = [];
  for (let i = 0; i < blockLines.length; i++) {
    const line = blockLines[i];
    if (isBlankOrComment(line)) continue;
    const ind = indentOf(line);
    if (ind < minIndent) continue;
    const keyMatch = line.match(new RegExp(`^\\s*${key}:\\s*$`));
    if (!keyMatch) continue;
    const keyIndent = ind;

    for (let j = i + 1; j < blockLines.length; j++) {
      const l = blockLines[j];
      if (isBlankOrComment(l)) continue;
      const li = indentOf(l);
      if (li <= keyIndent) break;
      const m = l.match(/^\s*-\s*(.+)\s*$/);
      if (m) {
        out.push(stripQuotes(stripInlineComment(m[1])));
      }
    }

    break;
  }
  return out;
}

function parseSlotUsageOverrides(classBlockLines, minIndent) {
  // Parses:
  //   slot_usage:
  //     slot_name:
  //       range: SomeClass
  const overrides = new Map();

  for (let i = 0; i < classBlockLines.length; i++) {
    const line = classBlockLines[i];
    if (isBlankOrComment(line)) continue;
    const ind = indentOf(line);
    if (ind < minIndent) continue;

    if (!line.match(/^\s*slot_usage:\s*$/)) continue;
    const usageIndent = ind;

    let currentSlot = null;
    let currentSlotIndent = null;

    for (let j = i + 1; j < classBlockLines.length; j++) {
      const l = classBlockLines[j];
      if (isBlankOrComment(l)) continue;
      const li = indentOf(l);
      if (li <= usageIndent) break;

      // Slot key line: `  slot_name:`
      if (li === usageIndent + 2) {
        const mKey = l.trim().match(/^([^\s:]+):\s*$/);
        if (mKey) {
          currentSlot = mKey[1];
          currentSlotIndent = li;
          continue;
        }
      }

      if (currentSlot && currentSlotIndent !== null && li > currentSlotIndent) {
        const mRange = l.match(/^\s*range:\s*(.+)\s*$/);
        if (mRange) {
          const range = stripQuotes(stripInlineComment(mRange[1]));
          if (range) overrides.set(currentSlot, range);
        }
      }
    }

    break;
  }

  return overrides;
}

function extractNamedMappingBlock(text, rootKey, itemName) {
  // Extract the YAML-ish block for `rootKey: { itemName: {...} }` without parsing YAML.
  // This is resilient to invalid YAML elsewhere in the file.
  const lines = text.split(/\r?\n/);
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i];
    if (isBlankOrComment(line)) continue;

    const rootMatch = line.match(new RegExp(`^\\s*${rootKey}:\\s*$`));
    if (!rootMatch) continue;
    const rootIndent = indentOf(line);

    for (let j = i + 1; j < lines.length; j++) {
      const l = lines[j];
      if (isBlankOrComment(l)) continue;
      const li = indentOf(l);
      if (li <= rootIndent) break;

      if (li === rootIndent + 2 && l.trim() === `${itemName}:`) {
        return {
          blockLines: collectIndentedBlock(lines, j, li),
          baseIndent: li,
        };
      }
    }
  }
  return null;
}

function extractAllNamedMappingBlocks(text, rootKey) {
  // Extract all mapping entry blocks under `rootKey:`
  // Example:
  //   classes:
  //     Foo:
  //       ...
  //     Bar:
  //       ...
  const lines = text.split(/\r?\n/);
  for (let i = 0; i < lines.length; i++) {
    const line = lines[i];
    if (isBlankOrComment(line)) continue;
    const rootMatch = line.match(new RegExp(`^\\s*${rootKey}:\\s*$`));
    if (!rootMatch) continue;

    const rootIndent = indentOf(line);
    const blocks = [];

    for (let j = i + 1; j < lines.length; j++) {
      const l = lines[j];
      if (isBlankOrComment(l)) continue;
      const li = indentOf(l);
      if (li <= rootIndent) break;

      if (li === rootIndent + 2) {
        const mKey = l.trim().match(/^([^\s:]+):\s*$/);
        if (mKey) {
          blocks.push({
            name: mKey[1],
            blockLines: collectIndentedBlock(lines, j, li),
            baseIndent: li,
          });
        }
      }
    }

    return blocks;
  }

  return [];
}

function main() {
  if (!fs.existsSync(MANIFEST_PATH)) {
    console.error(`[generate-ontology-uml] Missing manifest: ${MANIFEST_PATH}`);
    console.error('[generate-ontology-uml] Run pnpm run generate-manifest first.');
    process.exit(1);
  }

  const manifest = readJson(MANIFEST_PATH);

  const classCategory = (manifest.categories || []).find((c) => c.name === 'class');
  const slotCategory = (manifest.categories || []).find((c) => c.name === 'slot');

  const classFiles = safeArray(classCategory && classCategory.files);
  const slotFiles = safeArray(slotCategory && slotCategory.files);

  const slotIndex = new Map();
  for (const f of slotFiles) {
    const fullPath = path.join(SCHEMA_DIR, f.path);
    if (!fs.existsSync(fullPath)) continue;
    const text = readText(fullPath);
    const slotBlocks = extractAllNamedMappingBlocks(text, 'slots');
    for (const b of slotBlocks) {
      const range = findScalarInBlock(b.blockLines, 'range', b.baseIndent + 2);
      const multivaluedRaw = findScalarInBlock(b.blockLines, 'multivalued', b.baseIndent + 2);
      const multivalued = multivaluedRaw === 'true' || multivaluedRaw === 'True';

      if (!slotIndex.has(b.name)) {
        slotIndex.set(b.name, {
          range,
          multivalued,
        });
      }
    }
  }

  const classIndex = new Map();
  for (const f of classFiles) {
    const fullPath = path.join(SCHEMA_DIR, f.path);
    if (!fs.existsSync(fullPath)) continue;
    const text = readText(fullPath);
    const classBlocks = extractAllNamedMappingBlocks(text, 'classes');
    for (const b of classBlocks) {
      const baseIndent = b.baseIndent;
      const parent = findScalarInBlock(b.blockLines, 'is_a', baseIndent + 2);
      const slots = findListInBlock(b.blockLines, 'slots', baseIndent + 2);
      const overrides = parseSlotUsageOverrides(b.blockLines, baseIndent + 2);

      if (!classIndex.has(b.name)) {
        classIndex.set(b.name, {
          is_a: parent,
          slots,
          slot_usage_overrides: overrides,
        });
      }
    }
  }

  const classNames = [...classIndex.keys()].sort((a, b) => a.localeCompare(b));
  const lines = [];

  lines.push('```mermaid');
  lines.push('classDiagram');
  lines.push(`%% Generated from LinkML manifest: /schemas/20251121/linkml/manifest.json`);
  if (manifest.generated) {
    lines.push(`%% Manifest generated: ${manifest.generated}`);
  }
  lines.push('direction LR');

  for (const c of classNames) {
    lines.push(`class ${c}`);
  }

  const edgeSet = new Set();

  const addEdge = (a, b, kind, label) => {
    const key = `${a}|${b}|${kind}|${label || ''}`;
    if (edgeSet.has(key)) return;
    edgeSet.add(key);
    if (kind === 'inheritance') {
      lines.push(`${b} <|-- ${a}`);
      return;
    }
    if (kind === 'association') {
      lines.push(`${a} --> ${b} : ${label}`);
    }
  };

  for (const [className, classDef] of classIndex.entries()) {
    const parent = classDef.is_a;
    if (parent && classIndex.has(parent)) {
      addEdge(className, parent, 'inheritance');
    }

    const slots = safeArray(classDef.slots);
    const slotUsageOverrides = classDef.slot_usage_overrides instanceof Map ? classDef.slot_usage_overrides : new Map();

    for (const slotName of slots) {
      const slotDef = slotIndex.get(slotName) || {};
      const range = slotUsageOverrides.get(slotName) || slotDef.range;
      if (!range) continue;
      if (classIndex.has(range)) {
        addEdge(className, range, 'association', slotName);
      }
    }
  }

  lines.push('```');
  lines.push('');

  ensureDir(OUTPUT_PATH);
  fs.writeFileSync(OUTPUT_PATH, lines.join('\n'), 'utf8');
  console.log(`[generate-ontology-uml] Wrote ${OUTPUT_PATH}`);
  console.log(`[generate-ontology-uml] Classes: ${classIndex.size}, Slots indexed: ${slotIndex.size}, Edges: ${edgeSet.size}`);
}

main();