"use strict";

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


let scanning = 0;

let photoDB = null;

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

const processQueue = [], triedClean = [];

//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);
      }
    });
  });
}

function _scanDir(parent, path) {
  let re = new RegExp("\.((" + extensions.join(")|(") + "))$", "i"),
    replacements = {
      path: path.slice(picturesPath.length),
      name: path.replace(/.*\//, "").replace(/_/g, " "),
      parent: parent || null
    };

  /* Ensure that top level images are placed into an album with a root path */
  replacements.path = replacements.path || "/";

  let query = "SELECT id FROM albums WHERE path=:path AND ";
  if (!parent) {
    query += "parentId IS NULL";
  } else {
    query += "parentId=:parent";
  }

  return photoDB.sequelize.query(query, {
    replacements: replacements,
    type: photoDB.sequelize.QueryTypes.SELECT
  }).then(function(results) {
    if (results.length == 0) {
//      console.log("Adding " + path + " under " + parent, replacements);
      return photoDB.sequelize.query("INSERT INTO albums (path,parentId,name) VALUES(:path,:parent,:name)", {
        replacements: replacements
      }).spread(function(results, metadata) {
        return metadata.lastID;
      });
    } else {
      return results[0].id;
    }
  }).then(function(parent) {
    return new Promise(function(resolve, reject) {
      console.log("Scanning ..." + replacements.path);

      fs.readdir(path, function(err, files) {
        if (err) {
          console.warn("Could not readdir " + path);
          return resolve([]);
        }

        return resolve(files);
      });
    }).then(function(files) {
      scanning++;

      /* 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 mkdir(path + "/thumbs/scaled").then(function() {
        return Promise.map(files, function(file) {
          let filepath = path + "/" + file;

          return stat(filepath).then(function(stats) {
            if (stats.isDirectory()) {
              return scanDir(parent, filepath).catch(function(error) {
                console.warn("Could not scanDir " + filepath + ": " + error);
              });
            }

            /* Check file extensions */
            if (!re.exec(file)) {
              return;
            }
        
            const replacements = {
              path: path.slice(picturesPath.length),
              filename: file.replace(rawExtension, ".jpg") /* We will be converting from NEF/ORF => JPG */
            };

            replacements.path = replacements.path || "/";

            return photoDB.sequelize.query("SELECT id FROM photos WHERE path=:path AND filename=:filename", {
              replacements: replacements,
              type: photoDB.sequelize.QueryTypes.SELECT
            }).then(function(photo) {
              if (photo.length == 0) {
                processQueue.push([ replacements.path, file, stats.mtime, parent ]);
              }
            }).catch(function(error) {
              console.error("Sequelize.query failed: ", error);
            });
          }).catch(function(error) {
            console.warn("Could not stat " + filepath + ": " + error);
          });
        }, {
          concurrency: 1
        }).then(function() {
          scanning--;
          if (scanning == 0) {
            const endStamp = Date.now();
            console.log("Scanning completed in " + Math.round(((endStamp - startStamp))) + "ms. " + processQueue.length + " items to process.");
          }
        });
      });
    });
  });
}

const startStamp = Date.now();

let processRunning = false;

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

const sharp = require("sharp"), exif = require("exif-reader");
const stat = function (path) {
  if (path.indexOf(picturesPath) != 0) {
    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 + 1);
  }

  let parts = _path.split("/"), path;
  parts.unshift(picturesPath);
  return Promise.mapSeries(parts, function (part) {
    if (!path) {
      path = picturesPath;
    } 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 triggerWatcher() {
  setTimeout(triggerWatcher, 1000);
  
  if (!processRunning && processQueue.length) {
    let lastMessage = moment(), toProcess = processQueue.length, processing = processQueue.splice(0);
    processRunning = true;

    /* Sort to newest files to be processed first */
    processing.sort(function(a, b) {
      return b[2] - a[2];
    });

    return Promise.map(processing, function(entry) {
      var path = entry[0], file = entry[1], created = entry[2], albumId = entry[3];
        
      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 + "]";
              }
            }
          }

          let replacements = {
            albumId: albumId,
            name: file.replace(/.[^.]*$/, ""),
            path: path,
            filename: file,
            width: metadata.width,
            height: metadata.height,
            added: moment().format()
          };

          /* Ensure that top level images are placed into an album with a root path */
          replacements.path = replacements.path || "/";

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

            if (replacements.taken == "Invalid date" || replacements.taken.replace(/T.*/, "") == "1899-11-30") {
              console.log("Invalid EXIF date information: ", JSON.stringify(metadata.exif.exif));
              replacements.taken = replacements.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();
              }
            }
            replacements.taken = replacements.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("INSERT INTO photos " +
              "(albumId,path,filename,added,modified,taken,width,height,name)" +
              "VALUES(:albumId,:path,:filename,DATETIME(:added),DATETIME(:modified),DATETIME(:taken),:width,:height,:name)", {
              replacements: replacements
            });
          }).then(function() {
            toProcess--;
            if (moment().add(-5, 'seconds') > lastMessage) {
              console.log("Items to be processed: "  + toProcess);
              lastMessage = moment();
            }
          });
        }).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(entry[1])) {
              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, entry[1]);

                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);
            processQueue.push([ path, file, created, albumId ]);
          });
        });
      }).catch(function() {
        console.warn("Continuing file processing.");
      });
    }, {
      concurrency: 1
    }).then(function() {
      console.log("Completed processing queue.");
    });
  }
}
/*******************************************************************************************************/
function scanDir(parent, path) {
  let re = new RegExp("\.((" + extensions.join(")|(") + "))$", "i"),
    album = {
      path: path.slice(picturesPath.length) + "/",
      name: path.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()) {
          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;
        }
    
        assets.push({
          filename: file.replace(rawExtension, ".jpg"), /* We will be converting from NEF/ORF => JPG */
          name: file.replace(/.[^.]*$/, ""),
          stats: stats,
          album: album
        });
      });
    });
  }).then(function() {
    return [ albums, assets ];
  });
}

function findOrCreateDBAlbum(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: " + album.path);
      }
      return photoDB.sequelize.query("INSERT INTO albums (path,parentId,name) VALUES(:path,:parentId,:name)", {
        replacements: album
      }).spread(function(results, metadata) {
        return metadata.lastID;
      });
    } else {
      return results[0].id;
    }
  }).then(function(id) {
    album.id = id;
    return id;
  });
}

function findOrUpdateDBAsset(asset) {
  let query = "SELECT id,scanned 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) {
      /* Not in DB at all; HASH needs to be created. We could use the sharp loader to create
       * a buffer, then pass that around. It would complicate our code, so instead we will
       * leverage the OS' ability to cache read-only file assets in the cache and to pass
       * those to the sharp layer later :) Accordingly, we will load the file here, create a SHA
       * and create that HASH entry (unless it already exists, in which case DUPLICATE!!!! Gah.) */
      return photoDB.sequelize.query("INSERT INTO photos " +
        "(albumId,filename,name) " +
        "VALUES(:albumId,:filename,:name)", {
        replacements: asset
      }).spread(function(results, metadata) {
        return [ metadata.lastID, null ];
      });
    } else {
      return [ results[0].id, results[0].scanned ];
    }
  }).spread(function(id, scanned) {
    asset.id = id;
    asset.scanned = scanned;
    return asset;
  });
}

function computeHash(filepath) {
  return new Promise(function(resolve, reject) {
    try {
      const 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 {
          resolve(hash.digest("hex"));
        }
      });
    } catch(error) {
      console.error("Unable to create hash: " + error);
      return reject(error);
    }
  });
}

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, compute HASH of the file
     * 4. Check for HASH in photohash -- skip?
     * 5. Check for and create thumbs/FILE thumbs/scaled/FILE
     * 6. If necessary, create JPG from RAW
     * 7. Update last-scanned date in DB for entry
     * 8. 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();
    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();

      return Promise.mapSeries(albums, function(album) {
        return findOrCreateDBAlbum(album);
      }).then(function() {
        console.log("Processed " + albums.length + " album DB entries in " + 
          ((Date.now() - now) / 1000) + "s");
        now = Date.now();

        let processed = 0, start = Date.now(), last = 0, hashNeeded = [];
        return Promise.map(assets, function(asset) {
          return findOrUpdateDBAsset(asset).then(function(asset) {
            if (asset.scanned < asset.stats.mtime) {
              hashNeeded.push(asset);
            }
          }).then(function(asset) {
            processed++;

            let elapsed = Date.now() - start;
            if (elapsed < 5000) {
              return asset;
            }

            let remaining = assets.length - processed;
            console.log(remaining + " assets remaining. ETA " + 
              Math.ceil((elapsed / 1000) * remaining / (processed - last)) + "s");
            last = processed;
            start = Date.now();
          });
        }, {
          concurrency: 5
        }).then(function() {
          console.log(hashNeeded.length + " assets need HASH computed");
          return Promise.map(hashNeeded, function(asset) {
            return computeHash(picturesPath + asset.album.path + asset.filename).then(function(hash) {
              asset.hash = hash;
            });
          }).then(function() {
            let needsProcessing = [];
            return Promise.map(hashNeeded, function(asset) {
              return db.sequelize.query("SELECT hash FROM photohashes WHERE 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 {
                  return;
                }

                return db.sequelize.query(query, {
                  replacements: asset
                }).then(function() {
                  /* HASH has been updated; add to the needsProcessing array */
                  needsProcessing.push(asset.id);
                });
              });
            }, {
              concurrency: 5
            }).then(function() {
              if (!needsProcessing.length) {
                return;
              }

              /* 'needsProcessing' should only have their scanned stamp updated once thumbnails
               * have been created. */
              console.log(needsProcessing.length + " had their HASH updated. Updating scanned stamp.");
              return db.sequelize.query("UPDATE photos SET scanned=CURRENT_TIMESTAMP WHERE id IN (:scanned)", {
                replacements: {
                  scanned: needsProcessing
                }
              });
            });
          });
        }).then(function() {
          console.log("Processed " + assets.length + " asset DB entries in " + 
            ((Date.now() - now) / 1000) + "s");
        });
      });
      /*triggerWatcher();*/
    }).then(function() {
      console.log("Total time to initialize DB and all scans: " + ((Date.now() - initialized) / 1000) + "s");
    });
  }
};