"use strict";

const Promise = require("bluebird"),
  fs = require("fs"),
  config = require("config"),
  moment = require("moment"),
  crypto = require("crypto");


let photoDB = null;

const picturesPath = config.get("picturesPath").replace(/\/$/, "") + "/";

let processQueue = [], triedClean = [], lastScan;

//const rawExtension = /\.(nef|orf)$/i, extensions = [ "jpg", "jpeg", "png", "gif", "nef", "orf" ];

const rawExtension = /\.nef$/i, extensions = [ "jpg", "jpeg", "png", "gif", "nef" ];

function removeNewerFile(path, fileA, fileB) {
  fs.stat(path + fileA, function(err, statsA) {
    if (err) {
      return;
    }
    fs.stat(path + fileB, function(err, statsB) {
      if (err) {
        return;
      }
      if (statsA.mtime > statsB.mtime) {
        console.log("Removing file by moving to 'corrupt':" + fileA);
        moveCorrupt(path, fileA);
      } else {
        console.log("Removing file by moving to 'corrupt':" + fileB);
        moveCorrupt(path, fileB);
      }
    });
  });
}

let processRunning = false;

const { spawn } = require('child_process');

const sharp = require("sharp"), exif = require("exif-reader");
const stat = function (_path) {
  if (_path.indexOf(picturesPath.replace(/\/$/, "")) == 0) {
    _path = _path.substring(picturesPath.length);
  }

  let path = picturesPath + _path;

  return new Promise(function (resolve, reject) {
    fs.stat(path, function (error, stats) {
      if (error) {
        return reject(error);
      }
      return resolve(stats);
    });
  });
}

const mkdir = function (_path) {
  if (_path.indexOf(picturesPath) == 0) {
    _path = _path.substring(picturesPath.length);
  }

  let parts = _path.split("/"), path;
  
  parts.unshift(picturesPath);
  return Promise.mapSeries(parts, function (part) {
    if (!path) {
      path = picturesPath.replace(/\/$/, "");
    } else {
      path += "/" + part;
    }

    return stat(path).catch(function (error) {
      if (error.code != "ENOENT") {
        throw error;
      }

      return new Promise(function (resolve, reject) {
        fs.mkdir(path, function (error) {
          if (error) {
            return reject(error);
          }

          return resolve();
        });
      });
    });
  });
}

const exists = function(path) {
  return stat(path).then(function() {
    return true;
  }).catch(function() {
    return false;
  });
}

function convertRawToJpg(path, file) {
  console.log("Converting " + path + file);

  path = picturesPath + path;

  return new Promise(function(resolve, reject) {
    return exists(path + file.replace(rawExtension, ".jpg")).then(function(exist) {
      if (exist) {
        console.log("Skipping already converted file: " + file);
        return;
      }

      const ufraw = spawn("ufraw-batch", [
        "--silent",
        "--wb=camera",
        "--rotate=camera",
        "--out-type=jpg",
        "--compression=90",
        "--exif",
        "--overwrite",
        "--output", path + file.replace(rawExtension, ".jpg"),
        path + file
      ]);

      const stderr = [];
      ufraw.stderr.on('data', function(data) {
        stderr.push(data);
      });

      return new Promise(function(ufraw, resolve, reject) {
        ufraw.on('exit', function(stderr, code, signal) {
          if (signal || code != 0) {
            let error = "UFRAW for " + path + file + " returned an error: " + code + "\n" + signal + "\n" + stderr.join("\n") + "\n";
            console.error(error);
            return moveCorrupt(path, file).then(function() {
              console.warn("ufraw failed");
              return reject(error);
            }).catch(function(error) {
              console.warn("moveCorrupt failed");
              return reject(error);
            });
          }
          return mkdir(path + "raw").then(function() {
            fs.rename(path + file, path + "raw/" + file, function(err) {
              if (err) {
                console.error("Unable to move RAW file: " + path + file);
                return reject(err);
              }
              return resolve();
            });
          }).catch(function(error) {
            console.warn("mkdir failed");
            return reject(error);
          });
        }.bind(this, ufraw));
      }.bind(this, stderr));
    });
  });
}

function moveCorrupt(path, file) {
  if (path.indexOf(picturesPath) != 0) {
    path = picturesPath + path;
  }

  console.warn("Moving corrupt file '" + file + "' to " + path + "corrupt");

  return mkdir(path + "corrupt").then(function() {
    return new Promise(function(resolve, reject) {
      fs.rename(path + file, path + "corrupt/" + file, function(err) {
        if (err) {
          console.error("Unable to move corrupt file: " + path + file);
          return reject(err);
        }
        return resolve();
      });
    });
  });
}

function processBlock(items) {
  
  if (items) {
    processQueue = processQueue.concat(items);
  }
  
  if (processRunning) {
    /* Invoke once per second to check if there are items to process */
    setTimeout(processBlock, 1000);
    return;
  }

  let processing = processQueue.splice(0), needsProcessing = [], duplicates = [];

  processRunning = true;

  /* Sort to newest files to be processed first */
  processing.sort(function(a, b) {
    return a.stats.mtime - b.stats.mtime;
  });

  let toProcess = processing.length, lastMessage = moment();
  console.log("Items to be processed: "  + toProcess);
  return Promise.mapSeries(processing, function(asset) {
    return computeHash(picturesPath + asset.album.path + asset.filename).then(function(hash) {
      asset.hash = hash;
      return asset;
    }).then(function(asset) {
      return photoDB.sequelize.query("SELECT photohashes.*,photos.filename,albums.path FROM photohashes " +
        "LEFT JOIN photos ON (photos.id=photohashes.photoId) " +
        "LEFT JOIN albums ON (albums.id=photos.albumId) " +
        "WHERE hash=:hash OR photoId=:id", {
        replacements: asset,
        type: photoDB.sequelize.QueryTypes.SELECT
      }).then(function(results) {
        let query;

        if (results.length == 0) {
          query = "INSERT INTO photohashes (hash,photoId) VALUES(:hash,:id)";
        } else if (results[0].hash != asset.hash) {
          query = "UPDATE photohashes SET hash=:hash WHERE photoId=:id)";
        } else if (results[0].photoId != asset.id) {
          console.log("Duplicate asset: " + 
            "'" + asset.album.path + asset.filename + "' is a copy of " +
            "'" + results[0].path + results[0].filename + "'");
          duplicates.push(asset);
          return null;
        }

        /* Even if the hash doesn't need to be updated, the entry needs to be scanned */
        needsProcessing.push(asset);

        if (!query) {
          return asset;
        }

        return photoDB.sequelize.query(query, {
          replacements: asset,
        }).then(function() {
          return asset;
        });
      });
    }).then(function(asset) {
      if (!asset) { /* The processed entry is a DUPLICATE. Skip it. */
        return;
      }

      var path = asset.album.path,
        file = asset.filename,
        created = asset.stats.mtime,
        albumId = asset.album.id;
        
      let tmp = Promise.resolve(file);
      /* If this is a Nikon RAW file, convert it to JPG and move to /raw dir */
      if (rawExtension.exec(file)) {
        tmp = exists(picturesPath + path + file.replace(rawExtension, ".jpg")).then(function(exist) {
          if (exist) {
            return file.replace(rawExtension, ".jpg"); /* We converted from NEF/ORF => JPG */
          }
          
          return mkdir(picturesPath + path + "raw").then(function() {
            return convertRawToJpg(path, file);
          }).then(function() {
            return file.replace(rawExtension, ".jpg"); /* We converted from NEF/ORF => JPG */
          });
        });
      }

      return tmp.then(function(file) {
        var src = picturesPath + path + file,
          image = sharp(src);

        return image.limitInputPixels(1073741824).metadata().then(function(metadata) {
          if (metadata.exif) {
            metadata.exif = exif(metadata.exif);
            delete metadata.exif.thumbnail;
            delete metadata.exif.image;
            for (var key in metadata.exif.exif) {
              if (Buffer.isBuffer(metadata.exif.exif[key])) {
                metadata.exif.exif[key] = "Buffer[" + metadata.exif.exif[key].length + "]";
              }
            }
          }

          asset.width = metadata.width;
          asset.height = metadata.height;
          asset.added = moment().format();

          if (metadata.exif && metadata.exif.exif && metadata.exif.exif.DateTimeOriginal && !isNaN(metadata.exif.exif.DateTimeOriginal.valueOf())) {
            asset.taken = moment(metadata.exif.exif.DateTimeOriginal).format();
            asset.modified = moment(metadata.exif.exif.DateTimeOriginal).format();

            if (asset.taken == "Invalid date" || asset.taken.replace(/T.*/, "") == "1899-11-30") {
              console.log("Invalid EXIF date information for " + asset.album.path + asset.filename);
              asset.taken = asset.modified = moment(created).format();
            }
          } else {
            /* Attempt to infer the datestamp from the filename */
            let date = moment(created).format();

            let match = file.match(/WhatsApp Image (20[0-9][0-9]-[0-9][0-9]-[0-9][0-9]) at (.*).(jpeg|jpg)/);
            if (match) {
              date = moment((match[1]+" "+match[2]), "YYYY-MM-DD h.mm.ss a").format();
              if (date == "Invalid date") {
                date = moment(created).format();
              }
            } else {
              match = file.match(/(20[0-9][0-9]-?[0-9][0-9]-?[0-9][0-9])[_\-]?([0-9]{6})?/);
              if (match) {
                if (match[2]) { /* Stamp had time in it */
                  date = moment((match[1]+""+match[2]).replace(/-/g, ""), "YYYYMMDDHHmmss").format();
                } else {
                  date = moment(match[1].replace(/-/g, ""), "YYYYMMDD").format();
                }
                if (date == "Invalid date") {
                  date = moment(created).format();
                }
              } else {
                date = moment(created).format();
              }
            }
            asset.taken = asset.modified = date;
          }

          let dst = picturesPath + path + "thumbs/" + file;

          return exists(dst).then(function(exist) {
            if (exist) {
              return;
            }

            return image.resize(256, 256).toFile(dst).catch(function(error) {
              console.error("Error resizing image: " + dst, error);
              throw error;
            });
          }).then(function() {
            let dst = picturesPath + path + "thumbs/scaled/" + file;
            return exists(dst).then(function(exist) {
              if (exist) {
                return;
              }
  
              return image.resize(Math.min(1024, metadata.width)).toFile(dst).catch(function(error) {
                console.error("Error resizing image: " + dst, error);
                throw error;
              });
            });
          }).then(function() {
            return photoDB.sequelize.query("UPDATE photos SET " +
              "added=:added,modified=:modified,taken=:taken,width=:width,height=:height,scanned=CURRENT_TIMESTAMP " +
              "WHERE id=:id", {
              replacements: asset,
            });
          });
        }).catch(function(error) {
          console.error("Error reading image " + src + ": ", error);
          return moveCorrupt(path, file).then(function() {

            /* If the original file was not a NEF/ORF, we are done... */
            if (!rawExtension.exec(asset.filename)) {
              return;
            }

            /* ... otherwise, attempt to re-convert the NEF/ORF->JPG and then resize again */
            for (var i = 0; i < triedClean.length; i++) {
              if (triedClean[i] == path + file) {
                /* Move the NEF/ORF to /corrupt as well so it isn't re-checked again and again... */
                // return moveCorrupt(path, asset.filename);

                console.error("Already attempted to convert NEF/ORF to JPG: " + path + file);
                return;
              }
            }

            console.warn("Adding " + path + file + " back onto processing queue.");
            triedClean.push(path + file);
            processBlock([ path, file, created, albumId ]);
          });
        });
      }).catch(function() {
        console.warn("Continuing file processing.");
      });
    }).then(function() {
      toProcess--;
      if (moment().add(-5, 'seconds') > lastMessage) {
        console.log("Items to be processed: "  + toProcess);
        lastMessage = moment();
      }
    });
  }).catch(function(error) {
    console.log("Error processing file. Continuing.");
    throw error;
  }).then(function() {
    console.log("Completed processing queue. Marking " + duplicates.length + " duplicates.");
    let dups = [];
    duplicates.forEach(function(asset) {
      /* If not already marked as a duplicate, mark it. */
      if (!asset.duplicate) {
        dups.push(asset.id);
      }
    });

    if (dups.length == 0) {
      return;
    }

    return photoDB.sequelize.query("UPDATE photos SET duplicate=1,modified=CURRENT_TIMESTAMP,scanned=CURRENT_TIMESTAMP WHERE id IN (:dups)", {
      replacements: {
        dups: dups
      }
    });
  }).then(function() {
    console.log("Looking for removed assets");
    return photoDB.sequelize.query("SELECT photos.scanned,photos.id,photos.filename,albums.path FROM photos " +
        "LEFT JOIN albums ON (albums.id=photos.albumId) " +
        "WHERE photos.deleted=0 AND DATETIME(photos.scanned)<DATETIME(:lastScan)", {
      replacements: {
        lastScan: lastScan
      },
      type: photoDB.sequelize.QueryTypes.SELECT
    }).then(function(results) {
      let deleted = [];
      console.log("Checking " + results.length + " assets to see if they are on disk.");
      return Promise.map(results, function(asset) {
        return exists(asset.path + asset.filename).then(function(exist) {
          if (!exist) {
            console.log(asset.path + asset.filename + " no longer exists on disk. Marking as deleted.");
            deleted.push(asset.id);
          }
        });
      }).then(function() {
        return photoDB.sequelize.query("UPDATE photos SET deleted=1,scanned=CURRENT_TIMESTAMP WHERE id IN (:deleted)", {
          replacements: {
            deleted: deleted
          }
        }).then(function() {
          return photoDB.sequelize.query("DELETE FROM photohashes WHERE photoId IN (:deleted)", {
            replacements: {
              deleted: deleted
            }
          });
        }).then(function() {
          console.log(deleted.length + " assets deleted.");
        });
      });
    });
  }).then(function() {
    processRunning = false;
  });
}

function scanDir(parent, path) {
  let re = new RegExp("\.((" + extensions.join(")|(") + "))$", "i"),
    album = {
      path: path.slice(picturesPath.length), /* path already ends in '/' */
      name: path.replace(/\/$/, "").replace(/.*\//, "").replace(/_/g, " "),
      parent: parent,
      allAssetCount: 0,
      allAlbumCount: 0
    }, albums = [ album ], assets = [];
  
  return new Promise(function(resolve, reject) {
    fs.readdir(path, function(error, files) {
      if (error) {
        console.warn("Could not readdir: " + path);
        return resolve([]);
      }

      /* Remove 'thumbs' and 'raw' directories from being processed */
      files = files.filter(function(file) {
        for (var i = 0; i < files.length; i++) {
          /* If this file has an original NEF/ORF on the system, don't add the JPG to the DB */
          if (rawExtension.exec(files[i]) && file == files[i].replace(rawExtension, ".jpg")) {
            return false;
          }
          
          /* If there is a different CASE (eg. JPG vs jpg) don't add it, and remove the 'lower case' 
            * version from disk. */
          if (file != files[i] && file.toUpperCase() == files[i]) {
            removeNewerFile(path, file, files[i]);
            console.log("Duplicate file in " + path + ": ", file, files[i]);
            return false;
          }
        }

        return file != "raw" && file != "thumbs" && file != ".git" && file != "corrupt";
      });

      return resolve(files);
    });
  }).then(function(files) {
    return Promise.map(files, function(file) {
      let filepath = path + file;  
      return stat(filepath).then(function(stats) {
        if (stats.isDirectory()) {
          filepath += "/";
          return scanDir(album, filepath).spread(function(_albums, _assets) {
            album.allAssetCount += _assets.length;
            album.allAlbumCount += _albums.length + 1;
            albums = albums.concat(_albums);
            assets = assets.concat(_assets);
          }).catch(function(error) {
            console.warn("Could not scanDir " + filepath + ": " + error);
          });
        }

        /* Check file extensions */
        if (!re.exec(file)) {
          return;
        }

        album.hasAssets = true;

        assets.push({
          filename: file.replace(rawExtension, ".jpg"), /* We will be converting from NEF/ORF => JPG */
          name: file.replace(/.[^.]*$/, ""),
          stats: {
            mtime: stats.mtime
          },
          album: album
        });
      });
    });
  }).then(function() {
    return Promise.map(albums, function(album) {
      if (album.hasAssets) {
        return mkdir(album.path + "thumbs/scaled");
      }
    });
  }).then(function() {
    return [ albums, assets ];
  });
}

function findOrCreateDBAlbum(transaction, album) {
  let query = "SELECT id FROM albums WHERE path=:path AND ";
  if (!album.parent) {
    query += "parentId IS NULL";
    album.parentId = null;
  } else {
    if (!album.parent.id) {
      let error = "Albums in array in non ancestral order!";
      console.error(error);
      throw error;
    }
    album.parentId = album.parent.id;
    query += "parentId=:parentId";
  }

  return photoDB.sequelize.query(query, {
    replacements: album,
    type: photoDB.sequelize.QueryTypes.SELECT
  }).then(function(results) {
    if (results.length == 0) {
      if (!album.parent) {
        console.warn("Creating top level album: " + picturesPath);
      }
      return photoDB.sequelize.query("INSERT INTO albums (path,parentId,name) VALUES(:path,:parentId,:name)", {
        replacements: album,
        transaction: transaction
      }).spread(function(results, metadata) {
        return metadata.lastID;
      });
    } else {
      return results[0].id;
    }
  }).then(function(id) {
    album.id = id;
    return id;
  });
}

function findOrUpdateDBAsset(transaction, asset) {
  let query = "SELECT id,scanned,modified FROM photos WHERE albumId=:albumId AND filename=:filename";
  if (!asset.album || !asset.album.id) {
    let error = "Asset being processed without an album";
    console.error(error);
    throw error;
  }
  asset.albumId = asset.album.id;
  return photoDB.sequelize.query(query, {
    replacements: asset,
    type: photoDB.sequelize.QueryTypes.SELECT
  }).then(function(results) {
    if (results.length == 0) {
      return photoDB.sequelize.query("INSERT INTO photos " +
        "(albumId,filename,name) " +
        "VALUES(:albumId,:filename,:name)", {
        replacements: asset,
        transaction: transaction
      }).spread(function(results, metadata) {
        asset.id = metadata.lastID;
      });
    } else {
      asset.id = results[0].id;
      asset.scanned = results[0].scanned;
      asset.modified = results[0].modified;
    }
  }).then(function() {
    return asset;
  });
}

function computeHash(filepath) {
  return new Promise(function(resolve, reject) {
    let input = fs.createReadStream(filepath),
      hash = crypto.createHash("sha256");
    if (!input) {
      return reject()
    }

    input.on("readable", function() {
      const data = input.read();
      if (data) {
        hash.update(data);
      } else {
        input.close();
        resolve(hash.digest("hex"));
        hash = null;
        input = null;
      }
    });
  });
}

module.exports = {
  scan: function (db) {
    photoDB = db;
    /* 1. Scan for all assets which will be managed by the system. readdir
     * 2. Check if entry in DB. Check mod-time in DB vs. stats from #1
     *  - For albums
     *  - For assets
     * 3. If not in DB, or mod-time changed, queue for HASH CHECK
     * 
     * HASH CHECK
     * 1. Compute HASH
     * 2. Check for HASH in photohash -- skip?
     * 3. Check for and create thumbs/FILE thumbs/scaled/FILE
     * 4. If necessary, create JPG from RAW
     * 5. Update last-scanned date in DB for entry
     * 6. Look up all DB entries with last-scanned date < NOW -- purge from DB (they were 
     *    removed on disk)? Also purge from the HASH table.
     */
    let initialized = Date.now();
    let now = Date.now();
    let needsProcessing = [];

    lastScan = new Date();
    return scanDir(null, picturesPath).spread(function(albums, assets) {
      console.log("Found " + assets.length + " assets in " + albums.length + " albums after " + 
        ((Date.now() - now) / 1000) + "s");
      /* One at a time, in series, as the album[] array has parents first, then descendants.
       * Operating in parallel could result in a child being searched for prior to the parent */
      now = Date.now();

      let toProcess = albums.length, lastMessage = moment();
      return photoDB.sequelize.transaction(function(transaction) {
        return Promise.mapSeries(albums, function(album) {
          return findOrCreateDBAlbum(transaction, album).then(function() {
            toProcess--;
            if (moment().add(-5, 'seconds') > lastMessage) {
              console.log("Albums to be created in DB: "  + toProcess);
              lastMessage = moment();
            }
          });
        });
      }).then(function() {
        console.log("Processed " + albums.length + " album DB entries in " + 
          ((Date.now() - now) / 1000) + "s");
        now = Date.now();

        console.log(assets.length + " assets remaining to be verified/updated. ETA N/A");

        let processed = 0, start = Date.now(), last = 0, updateScanned = [], newEntries = 0;
        return photoDB.sequelize.transaction(function(transaction) {
          return Promise.map(assets, function(asset) {
            return findOrUpdateDBAsset(transaction, asset).then(function(asset) {
              if (!asset.scanned) {
                newEntries++;
              }
              if (!asset.scanned || asset.scanned < asset.stats.mtime || !asset.modified) {
                needsProcessing.push(asset);
              } else {
                updateScanned.push(asset.id);
              }
            }).then(function(asset) {
              processed++;
  
              let elapsed = Date.now() - start;
              if (elapsed < 5000) {
                return asset;
              }
  
              let remaining = assets.length - processed, eta = Math.ceil((elapsed / 1000) * remaining / (processed - last));
              console.log(remaining + " assets remaining be verified/updated " +
                "(" + newEntries + " new entries, " + (processed - newEntries) + " up-to-date so far). ETA " + eta + "s");
              last = processed;
              start = Date.now();
            });
          }, {
            concurrency: 10
          });
        }).then(function() {
          if (updateScanned.length) {
            return photoDB.sequelize.query("UPDATE photos SET scanned=CURRENT_TIMESTAMP WHERE id IN (:ids)", {
              replacements: {
                ids: updateScanned
              }
            }).then(function() {
              console.log("Updated scan date of " + updateScanned.length + " assets");
              updateScanned = [];
            });
          }
        }).then(function() {
          console.log(newEntries + " assets are new. " + (needsProcessing.length - newEntries) + " assets have been modified.");
          console.log(needsProcessing.length + " assets need HASH computed. " + (assets.length - needsProcessing.length) + " need no update.");;
          processBlock(needsProcessing);
          needsProcessing = [];
        }).then(function() {
          console.log("Scanned " + assets.length + " asset DB entries in " + 
            ((Date.now() - now) / 1000) + "s");
          assets = [];
        });
      });
    }).then(function() {
      console.log("Total time to initialize DB and all scans: " + ((Date.now() - initialized) / 1000) + "s");
    });
  }
};