/**
 * .prproj Remapper Module
 *
 * Decompresses a Premiere Pro project file (gzipped XML), parses the media references,
 * and swaps .gves file paths with their paired high-res media paths using the
 * proxy linkage structure embedded in the project.
 *
 * The .prproj structure for FramelightX imports:
 *   - Each clip has a .gves Media block (the active media during editing)
 *   - Each clip also has a paired high-res Media block (marked IsProxy=true, OfflineReason=1)
 *   - AudioProxy/VideoProxy elements link .gves blocks → high-res blocks via ProxyMedia ObjectURef
 *
 * This module:
 *   1. Finds all .gves Media blocks
 *   2. Follows proxy linkages to find paired high-res paths
 *   3. Replaces .gves paths with high-res UNC paths
 *   4. Removes IsProxy/OfflineReason flags so AME treats high-res as online
 *   5. Clears the FramelightX ImplementationID so AME uses native importers
 */

const zlib = require('zlib');
const { XMLParser, XMLBuilder } = require('fast-xml-parser');

// FramelightX plugin importer GUID
const FRAMELIGHTX_IMPL_ID = '1fa18bfa-255c-44b1-ad73-56bcd99fceaf';
const NULL_IMPL_ID = '00000000-0000-0000-0000-000000000000';

/**
 * Remap a .prproj buffer, swapping .gves references with high-res media paths.
 * Uses string-based XML manipulation to preserve the exact XML structure that
 * Premiere expects (XML parsers tend to reformat and break .prproj files).
 *
 * @param {Buffer} prprojBuffer - The raw .prproj file (gzipped)
 * @param {Object} options - Optional config { hiresMediaFolder: string, fsModule?: fs }
 * @returns {Object} { buffer: Buffer, report: Object }
 */
async function remapPrproj(prprojBuffer, options = {}) {
  // Step 1: Decompress
  const xml = zlib.gunzipSync(prprojBuffer).toString('utf-8');

  // Step 2: Build a map of all Media blocks by ObjectUID
  const mediaBlocks = parseMediaBlocks(xml);

  // Step 3: Build proxy linkage map (gves ObjectUID → high-res ObjectUID)
  const proxyLinks = parseProxyLinks(xml, mediaBlocks);

  // Step 4: Perform the path swaps
  const { remappedXml, swaps } = performSwaps(xml, mediaBlocks, proxyLinks, options);

  // Step 5: Recompress
  const outputBuffer = zlib.gzipSync(Buffer.from(remappedXml, 'utf-8'));

  const report = {
    totalMediaBlocks: Object.keys(mediaBlocks).length,
    gvesBlocks: Object.values(mediaBlocks).filter(m => m.isGves).length,
    highResBlocks: Object.values(mediaBlocks).filter(m => m.isProxy).length,
    swapsPerformed: swaps.length,
    swaps: swaps,
    // "Unmapped" = .gves paths that were NOT covered by any swap (path-level, not block-level).
    // Multiple Media blocks can share the same .gves path (video+audio streams), which is fine
    // because the global string replacement catches all of them.
    unmappedGves: (() => {
      const swappedPaths = new Set(swaps.map(s => s.oldPath.toLowerCase()));
      const unmapped = Object.values(mediaBlocks)
        .filter(m => m.isGves && !swappedPaths.has(m.filePath.toLowerCase()));
      // Deduplicate by path
      const seen = new Set();
      return unmapped.filter(m => {
        if (seen.has(m.filePath.toLowerCase())) return false;
        seen.add(m.filePath.toLowerCase());
        return true;
      }).map(m => ({ uid: m.objectUid, path: m.filePath }));
    })()
  };

  return { buffer: outputBuffer, report };
}

/**
 * Parse all <Media> blocks from the XML and extract key properties.
 * Uses regex to avoid XML parser reformatting issues.
 */
function parseMediaBlocks(xml) {
  const blocks = {};
  // Match Media blocks with ObjectUID attribute
  const mediaRegex = /<Media\s+ObjectUID="([^"]+)"[^>]*>([\s\S]*?)<\/Media>/g;
  let match;

  while ((match = mediaRegex.exec(xml)) !== null) {
    const uid = match[1];
    const body = match[2];

    const filePath = extractTag(body, 'FilePath');
    const actualMediaFilePath = extractTag(body, 'ActualMediaFilePath');
    const isProxy = extractTag(body, 'IsProxy') === 'true';
    const offlineReason = extractTag(body, 'OfflineReason');
    const implementationID = extractTag(body, 'ImplementationID');
    const title = extractTag(body, 'Title');
    const relativePath = extractTag(body, 'RelativePath');

    const isGves = filePath && filePath.toLowerCase().endsWith('.gves');

    blocks[uid] = {
      objectUid: uid,
      filePath,
      actualMediaFilePath,
      relativePath,
      isProxy,
      offlineReason,
      implementationID,
      title,
      isGves,
      fullMatch: match[0],
      startIndex: match.index
    };
  }

  return blocks;
}

/**
 * Parse AudioProxy and VideoProxy elements to build the linkage map.
 * Structure: The proxy element is a child of a clip content block that references
 * a .gves Media block. The proxy element's ProxyMedia ObjectURef points to the
 * high-res Media block.
 */
function parseProxyLinks(xml, mediaBlocks) {
  const links = {}; // highResUid → Set of gvesUids it's proxied by

  // Find all AudioProxy elements
  const proxyRegex = /<(?:Audio|Video)Proxy\s+ObjectID="[^"]*"[^>]*>([\s\S]*?)<\/(?:Audio|Video)Proxy>/g;
  let match;

  while ((match = proxyRegex.exec(xml)) !== null) {
    const body = match[1];
    const proxyMediaRef = extractAttr(body, 'ProxyMedia', 'ObjectURef');

    if (proxyMediaRef && mediaBlocks[proxyMediaRef]) {
      // proxyMediaRef points to the high-res (IsProxy=true) block
      if (!links[proxyMediaRef]) {
        links[proxyMediaRef] = new Set();
      }
    }
  }

  // Now we need to figure out which .gves block maps to which high-res block.
  // The relationship is: a clip's content references a .gves Media block AND has
  // AudioProxy/VideoProxy children that point to high-res blocks.
  //
  // Simpler approach: match by file name/title similarity, or by the fact that
  // .gves and high-res blocks for the same clip appear in sequence and share
  // the same Start timecode.
  //
  // Most reliable: match by Start timecode, which is identical for paired blocks.

  const gvesBlocks = Object.values(mediaBlocks).filter(m => m.isGves);
  const hiresBlocks = Object.values(mediaBlocks).filter(m => m.isProxy);

  // Build a map from .gves UID → high-res block by matching via AudioProxy structure.
  // We look for content blocks that contain both a Media ObjectURef (to .gves) and
  // AudioProxy elements (pointing to high-res).
  const gvesToHires = {};

  // Strategy: find <Content> blocks that tie .gves Media to AudioProxy
  const contentRegex = /<Content[^>]*>([\s\S]*?)<\/Content>/g;
  while ((match = contentRegex.exec(xml)) !== null) {
    const body = match[1];

    // Find the Media ObjectURef in this content block
    const mediaRef = extractAttr(body, 'Media', 'ObjectURef');
    if (!mediaRef || !mediaBlocks[mediaRef] || !mediaBlocks[mediaRef].isGves) continue;

    // Find AudioProxy references in this content block
    const audioProxyRefs = [];
    const apRegex = /<AudioProxyItem[^>]*ObjectRef="([^"]*)"[^>]*\/>/g;
    let apMatch;
    while ((apMatch = apRegex.exec(body)) !== null) {
      audioProxyRefs.push(apMatch[1]);
    }

    // For each AudioProxy ObjectRef, find the actual AudioProxy element and its ProxyMedia
    for (const apRef of audioProxyRefs) {
      const apRegex2 = new RegExp(
        `<(?:Audio|Video)Proxy\\s+ObjectID="${apRef}"[^>]*>([\\s\\S]*?)<\\/(?:Audio|Video)Proxy>`
      );
      const apMatch2 = apRegex2.exec(xml);
      if (apMatch2) {
        const proxyMediaRef = extractAttr(apMatch2[1], 'ProxyMedia', 'ObjectURef');
        if (proxyMediaRef && mediaBlocks[proxyMediaRef] && mediaBlocks[proxyMediaRef].isProxy) {
          gvesToHires[mediaRef] = proxyMediaRef;
          break;
        }
      }
    }
  }

  // Fallback: if Content-based matching didn't catch everything, try Start timecode matching
  for (const gves of gvesBlocks) {
    if (gvesToHires[gves.objectUid]) continue;

    const gvesStart = extractTag(
      xml.substring(gves.startIndex, gves.startIndex + gves.fullMatch.length),
      'Start'
    );

    if (!gvesStart) continue;

    for (const hires of hiresBlocks) {
      if (Object.values(gvesToHires).includes(hires.objectUid)) continue;

      const hiresStart = extractTag(
        xml.substring(hires.startIndex, hires.startIndex + hires.fullMatch.length),
        'Start'
      );

      if (hiresStart === gvesStart) {
        gvesToHires[gves.objectUid] = hires.objectUid;
        break;
      }
    }
  }

  return gvesToHires;
}

/**
 * Try to find a high-res file in the media folder when the .prproj doesn't have a path.
 * Strategy: Look for files in the high-res media folder that might correspond to this .gves.
 *
 * For example:
 *   - .gves file: "01KMR6YXTCJHG0AGMWVF98JRMWC--01.gves"
 *   - Media blocks may have metadata (Title) like "ZacIsCool--File7"
 *   - High-res folder has: "ZacIsCool--File7.mp4"
 *
 * Fallback strategy:
 *   1. If hiresBlock has a Title, search for that title in the high-res folder
 *   2. Search for common video/audio extensions (.mp4, .mov, .wav, etc.)
 *   3. If still not found, return null (path won't be swapped)
 *
 * @param {string} gvesPath - The .gves file path
 * @param {string} hiresTitle - Title from the high-res Media block
 * @param {string} hiresMediaFolder - UNC/SMB path to search
 * @param {Object} fs - File system module
 * @returns {string|null} The high-res file path if found, null otherwise
 */
function findHighResFileForGves(gvesPath, hiresTitle, hiresMediaFolder, fs) {
  if (!hiresMediaFolder) return null;

  try {
    // Normalize the folder path
    const searchFolder = hiresMediaFolder.replace(/\\/g, '/').replace(/\/$/, '');

    // If Title is provided, search for files containing that title
    if (hiresTitle) {
      try {
        const files = fs.readdirSync(searchFolder);
        const videoExts = new Set(['.mp4', '.mov', '.mxf', '.wav', '.aif', '.aiff']);
        const titleLower = hiresTitle.toLowerCase();

        // Look for files that contain the title as a substring
        for (const file of files) {
          const ext = '.' + file.split('.').pop().toLowerCase();
          if (!videoExts.has(ext)) continue;

          const fileLower = file.toLowerCase();
          // Match if filename contains the title
          if (fileLower.includes(titleLower)) {
            const fullPath = `${searchFolder}/${file}`;
            return fullPath.replace(/\//g, '\\');
          }
        }
      } catch (e) {
        // Ignore folder read failures, fall through to secondary search
      }
    }

    // Fallback: list files in the folder and try to match by base name
    try {
      const files = fs.readdirSync(searchFolder);
      const videoExts = new Set(['.mp4', '.mov', '.mxf', '.wav', '.aif', '.aiff']);

      // Extract base name from .gves path (without extension)
      const gvesFilename = gvesPath.split('\\').pop().split('/').pop();
      const gvesBaseName = gvesFilename.replace(/\.[^.]+$/, '').toLowerCase();

      // Look for files that might match
      for (const file of files) {
        const ext = '.' + file.split('.').pop().toLowerCase();
        if (!videoExts.has(ext)) continue;

        const fileBaseName = file.replace(/\.[^.]+$/, '').toLowerCase();

        // Partial match: if the file name contains a key part of the gves name
        if (fileBaseName.includes(gvesBaseName.substring(0, Math.min(8, gvesBaseName.length)))) {
          const fullPath = `${searchFolder}/${file}`;
          return fullPath.replace(/\//g, '\\');
        }
      }
    } catch (e) {
      // Folder read failed, return null
      return null;
    }
  } catch (e) {
    // Any errors during lookup, return null
    return null;
  }

  return null;
}

/**
 * Perform the actual path swaps in the XML string.
 * @param {string} xml - The project XML
 * @param {Object} mediaBlocks - Parsed media blocks
 * @param {Object} proxyLinks - Proxy linkage map
 * @param {Object} options - { hiresMediaFolder?: string, fsModule?: fs }
 */
function performSwaps(xml, mediaBlocks, proxyLinks, options = {}) {
  let remappedXml = xml;
  const swaps = [];
  const fs = options.fsModule || require('fs');

  // Collect all unique .gves UIDs that have a mapped high-res block
  const gvesUids = Object.keys(proxyLinks);

  for (const gvesUid of gvesUids) {
    const hiresUid = proxyLinks[gvesUid];
    const gvesBlock = mediaBlocks[gvesUid];
    const hiresBlock = mediaBlocks[hiresUid];

    if (!gvesBlock || !hiresBlock) continue;

    let hiresPath = hiresBlock.filePath;

    // Fallback: if high-res path is null, try to find it in the media folder
    if (!hiresPath && options.hiresMediaFolder && gvesBlock.filePath) {
      hiresPath = findHighResFileForGves(
        gvesBlock.filePath,
        hiresBlock.title || gvesBlock.title,
        options.hiresMediaFolder,
        fs
      );
    }

    if (!hiresPath) continue;

    const hiresTitle = hiresBlock.title || pathToTitle(hiresPath);

    // Calculate relative path for the high-res file
    const hiresRelativePath = hiresPath; // UNC paths don't use relative paths

    swaps.push({
      gvesUid,
      hiresUid,
      oldPath: gvesBlock.filePath,
      newPath: hiresPath,
      newTitle: hiresTitle
    });

    // Replace ALL occurrences of this .gves path in the entire XML.
    // This catches FilePath, ActualMediaFilePath, and any other references.
    const gvesPath = gvesBlock.filePath;
    const gvesPathEscaped = escapeRegex(gvesPath);

    // Replace FilePath tags containing this .gves path
    remappedXml = remappedXml.replace(
      new RegExp(`<FilePath>${gvesPathEscaped}</FilePath>`, 'g'),
      `<FilePath>${hiresPath}</FilePath>`
    );

    // Replace ActualMediaFilePath tags
    remappedXml = remappedXml.replace(
      new RegExp(`<ActualMediaFilePath>${gvesPathEscaped}</ActualMediaFilePath>`, 'g'),
      `<ActualMediaFilePath>${hiresPath}</ActualMediaFilePath>`
    );

    // Replace RelativePath tags for this .gves
    if (gvesBlock.relativePath) {
      const relPathEscaped = escapeRegex(gvesBlock.relativePath);
      remappedXml = remappedXml.replace(
        new RegExp(`<RelativePath>${relPathEscaped}</RelativePath>`, 'g'),
        `<RelativePath>${hiresPath}</RelativePath>`
      );
    }

    // Replace Title tags that match the .gves filename
    const gvesFilename = gvesPath.split('\\').pop().split('/').pop();
    if (gvesFilename) {
      const gvesTitleEscaped = escapeRegex(gvesFilename);
      remappedXml = remappedXml.replace(
        new RegExp(`<Title>${gvesTitleEscaped}</Title>`, 'g'),
        `<Title>${hiresTitle}</Title>`
      );
    }

    // Replace ImplementationID (FramelightX → null GUID so AME uses native importer)
    remappedXml = remappedXml.replace(
      new RegExp(`<ImplementationID>${escapeRegex(FRAMELIGHTX_IMPL_ID)}</ImplementationID>`, 'g'),
      `<ImplementationID>${NULL_IMPL_ID}</ImplementationID>`
    );
  }

  // Remove IsProxy and OfflineReason from high-res blocks so they're treated as online
  remappedXml = remappedXml.replace(/\s*<IsProxy>true<\/IsProxy>/g, '');
  remappedXml = remappedXml.replace(/\s*<OfflineReason>\d+<\/OfflineReason>/g, '');

  return { remappedXml, swaps };
}

// ─── Utility functions ─────────────────────────────────────────────

function extractTag(xml, tagName) {
  const regex = new RegExp(`<${tagName}>([^<]*)</${tagName}>`);
  const match = regex.exec(xml);
  return match ? match[1] : null;
}

function extractAttr(xml, tagName, attrName) {
  const regex = new RegExp(`<${tagName}\\s+${attrName}="([^"]*)"`, '');
  const match = regex.exec(xml);
  return match ? match[1] : null;
}

function escapeRegex(str) {
  return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

function pathToTitle(filePath) {
  const filename = filePath.split('\\').pop().split('/').pop();
  // Remove extension
  return filename.replace(/\.[^.]+$/, '');
}

/**
 * Analyze a .prproj file without modifying it.
 * Returns a report of all media references and their linkages.
 */
async function analyzePrproj(prprojBuffer) {
  const xml = zlib.gunzipSync(prprojBuffer).toString('utf-8');
  const mediaBlocks = parseMediaBlocks(xml);
  const proxyLinks = parseProxyLinks(xml, mediaBlocks);

  const gvesEntries = Object.values(mediaBlocks).filter(m => m.isGves);
  const hiresEntries = Object.values(mediaBlocks).filter(m => m.isProxy);

  // Debug: log all media blocks found
  console.log('=== DEBUG: All Media Blocks ===');
  Object.entries(mediaBlocks).forEach(([uid, block]) => {
    console.log(`UID: ${uid}`);
    console.log(`  FilePath: ${block.filePath}`);
    console.log(`  IsGves: ${block.isGves}`);
    console.log(`  IsProxy: ${block.isProxy}`);
    console.log(`  Title: ${block.title}`);
    console.log('---');
  });
  console.log('=== DEBUG: Proxy Links ===');
  console.log(JSON.stringify(proxyLinks, null, 2));

  // Deduplicate mappings by .gves path (multiple blocks can share the same path)
  const mappings = [];
  const seenGvesPaths = new Set();
  for (const [gvesUid, hiresUid] of Object.entries(proxyLinks)) {
    const gves = mediaBlocks[gvesUid];
    const hires = mediaBlocks[hiresUid];
    const gvesPath = gves ? gves.filePath.toLowerCase() : '';
    if (seenGvesPaths.has(gvesPath)) continue;
    seenGvesPaths.add(gvesPath);
    mappings.push({
      gvesPath: gves ? gves.filePath : 'unknown',
      hiresPath: hires ? hires.filePath : 'unknown',
      hiresExtension: hires ? hires.filePath.split('.').pop().toLowerCase() : 'unknown'
    });
  }

  // Count unique unmapped .gves paths
  const unmappedPaths = new Set();
  for (const g of gvesEntries) {
    if (!seenGvesPaths.has(g.filePath.toLowerCase())) {
      unmappedPaths.add(g.filePath.toLowerCase());
    }
  }

  // Debug: include all media blocks so we can see the structure
  const allMediaBlocks = Object.entries(mediaBlocks).map(([uid, block]) => ({
    uid,
    filePath: block.filePath,
    isGves: block.isGves,
    isProxy: block.isProxy,
    title: block.title,
    implementationID: block.implementationID
  }));

  return {
    totalMediaBlocks: Object.keys(mediaBlocks).length,
    gvesReferences: gvesEntries.length,
    hiresReferences: hiresEntries.length,
    mappedPairs: mappings.length,
    unmappedGves: unmappedPaths.size,
    mappings,
    hiresFormats: [...new Set(mappings.map(m => m.hiresExtension))],
    // Debug: include raw media blocks
    _debug_mediaBlocks: allMediaBlocks,
    _debug_proxyLinks: proxyLinks
  };
}

module.exports = { remapPrproj, analyzePrproj };