"use strict";

const express = require("express"),
  Promise = require("bluebird");

let photoDB;

require("../db/photos").then(function(db) {
  photoDB = db;
});

const router = express.Router();

const addOrUpdateIdentity = async(id, {
    displayName,
    firstName,
    lastName,
    middleName
  }, res) => {

  if (displayName === undefined
    || firstName === undefined
    || lastName === undefined
    || middleName === undefined) {
    res.status(400).send({ message: `Missing fields` });
    return undefined;
  }

  const identity = {
    displayName,
    firstName,
    lastName,
    middleName,
    id
  };

  if (id === -1 || !id) {
    const [results, { lastId }] = await photoDB.sequelize.query(
      `INSERT INTO identities ` +
      '(displayName,firstName,lastName,middleName)' +
      'VALUES(:displayName,:firstName,:lastName,:middleName)', {
      replacements: identity
    });
    identity.id = lastId;
  } else {
   await photoDB.sequelize.query(
      `UPDATE identities ` +
      'SET ' +
      'displayName=:displayName, ' +
      'firstName=:firstName, ' +
      'lastName=:lastName, ' +
      'middleName=:middleName ' +
      'WHERE id=:id', {
      replacements: identity
    });
  }

  return identity;
};


const populateRelatedFaces = async (identity, count) => {
  let limit = '';
  if (count) {
    limit = ` LIMIT ${count} `;
  }
  /* If this is a new identity, no faces are being requested --
   * just return the empty 'unknown face'. 
   * 
   * Otherwise, query the DB for 'count' faces */
  if (count === undefined) {
    identity.relatedFaces = await photoDB.sequelize.query(
      "SELECT id AS faceId,photoId,faceConfidence " +
      "FROM faces " +
      "WHERE identityId=:identityId " +
      limit, {
        replacements: { identityId: identity.id },
        type: photoDB.Sequelize.QueryTypes.SELECT,
        raw: true
    });
  } else {
    identity.relatedFaces = [];
  }

  /* If there are no faces, return the 'unknown face' */
  if (identity.relatedFaces.length === 0) {
    identity.relatedFaces.push({
      faceId: -1,
      photoId: -1,
      faceConfidence: 0
    });
  }

  identity.relatedFaces.forEach(face => {
    face.identityId = identity.id;
    face.distance = face.faceConfidence;
    face.descriptors = [];
    delete face.faceConfidence;
  });
}

router.post('/', async (req, res) => {
  console.log(`POST ${req.url}`)
  if (!req.user.maintainer) {
    console.warn(`${req.user.name} attempted to modify photos.`);
    return res.status(401).send({ message: "Unauthorized to modify photos." });
  }

  const identity = await addOrUpdateIdentity(-1, req.body, res);
  if (!identity) {
    return;
  }
  populateRelatedFaces(identity, 1);
  return res.status(200).send(identity);
});

router.put('/:id', async (req, res) => {
  console.log(`PUT ${req.url}`)
  if (!req.user.maintainer) {
    console.warn(`${req.user.name} attempted to modify photos.`);
    return res.status(401).send({ message: "Unauthorized to modify photos." });
  }

  const { id } = req.params;
  if (!id || isNaN(+id)) {
    return res.status(400).send({ message: `Invalid identity id ${id}` });
  }

  const identity = await addOrUpdateIdentity(id, req.body, res);
  if (!identity) {
    return;
  }
  populateRelatedFaces(identity);
  return res.status(200).send(identity);
});

router.put("/faces/remove/:id", (req, res) => {
  console.log(`PUT ${req.url}`)
  if (!req.user.maintainer) {
    console.warn(`${req.user.name} attempted to modify photos.`);
    return res.status(401).send({ message: "Unauthorized to modify photos." });
  }

  const id = parseInt(req.params.id);
  if (id != req.params.id) {
    return res.status(400).send({ message: "Invalid identity id." });
  }

  if (!Array.isArray(req.body.faces) || req.body.faces.length == 0) {
    return res.status(400).send({ message: "No faces supplied." });
  }

  return photoDB.sequelize.query(
    "UPDATE faces SET identityId=null " +
    "WHERE id IN (:faceIds)", {
    replacements: {
      identityId: id,
      faceIds: req.body.faces
    }
  }).then(() => {
    const identity = {
      id: id,
      faces: req.body.faces
    };
    return res.status(200).json(identity);
  }).catch((error) => {
    console.error(error);
    return res.status(500).send({message: "Error processing request." });
  });
});

router.put("/faces/add/:id", async (req, res) => {
  if (!req.user.maintainer) {
    console.warn(`${req.user.name} attempted to modify photos.`);
    return res.status(401).send("Unauthorized to modify photos.");
  }

  const id = parseInt(req.params.id);
  if (id != req.params.id) {
    return res.status(400).send("Invalid identity id.");
  }
  
  if (!Array.isArray(req.body.faces) || req.body.faces.length == 0) {
    return res.status(400).send("No faces supplied.");
  }

  try {
    await photoDB.sequelize.query(
      "UPDATE faces SET identityId=:identityId,classifiedBy='human' " +
      "WHERE id IN (:faceIds)", {
      replacements: {
        identityId: id,
        faceIds: req.body.faces
      }
    });
    const identity = {
      id: id,
      faces: req.body.faces
    };
    return res.status(200).json([identity]);
  } catch (error) {
    console.error(error);
    return res.status(500).send("Error processing request.");
  };
});

router.post("/", (req, res) => {
  if (!req.user.maintainer) {
    console.warn(`${req.user.name} attempted to modify photos.`);
    return res.status(401).send("Unauthorized to modify photos.");
  }
  const identity = {
    lastName: req.body.lastName || "",
    firstName: req.body.firstName || "",
    middleName: req.body.middleName || ""
  };
  identity.name = req.body.name || (identity.firstName + " " + identity.lastName);

  let fields = [];
  for (let key in identity) {
    fields.push(key);
  }

  if (!Array.isArray(req.body.faces) || req.body.faces.length == 0) {
    return res.status(400).send("No faces supplied.");
  }

  return photoDB.sequelize.query("INSERT INTO identities " +
    "(" + fields.join(",") + ") " +
    "VALUES(:" + fields.join(",:") + ")", {
    replacements: identity,
  }).then(([ results, metadata ]) => {
    identity.id = metadata.lastID;
    return photoDB.sequelize.query(
      "UPDATE faces SET identityId=:identityId " +
      "WHERE id IN (:faceIds)", {
      replacements: {
        identityId: identity.id,
        faceIds: req.body.faces
      }
    }).then(() => {
      identity.faces = req.body.faces;
      return res.status(200).json([identity]);
    });
  }).catch((error) => {
    console.error(error);
    return res.status(500).send("Error processing request.");
  });
});

function bufferToFloat32Array(buffer) {
  return new Float64Array(buffer.buffer, buffer.byteOffset, buffer.byteLength / Float64Array.BYTES_PER_ELEMENT);
}

function euclideanDistance(a, b) {
  let A = bufferToFloat32Array(a);
  let B = bufferToFloat32Array(b);
  let sum = 0;
  for (let i = 0; i < A.length; i++) {
    let delta = A[i] - B[i];
    sum += delta * delta;
  }
  return Math.sqrt(sum);
}

const getUnknownIdentity = async (faceCount) => {
  const unknownIdentity = {
    identityId: -1,
    lastName: '',
    firstName: '',
    middleName: '',
    displayName: 'Unknown',
    descriptors: [],
    relatedFaces: []
  };
  const limit = faceCount 
  ? ` LIMIT ${faceCount} ` 
  : ' ORDER BY faceConfidence DESC ';
  unknownIdentity.relatedFaces = await photoDB.sequelize.query(
    "SELECT id AS faceId,photoId,faceConfidence " +
    "FROM faces WHERE identityId IS NULL AND classifiedBy != 'not-a-face' " +
    limit, {
    type: photoDB.Sequelize.QueryTypes.SELECT,
    raw: true
  });
  if (unknownIdentity.relatedFaces.length === 0) {
    unknownIdentity.relatedFaces.push({
      faceId: -1,
      photoId: -1,
      faceConfidence: 0
    });
  }
  unknownIdentity.relatedFaces.forEach(face => {
    face.identityId = -1;
    face.distance = face.faceConfidence;
    face.descriptors = [];
    delete face.faceConfidence;
  });
  return unknownIdentity;
}

router.get("/:id?", async (req, res) => {
  console.log(`GET ${req.url}`);

  let id;

  if (req.params.id) {
    id = parseInt(req.params.id);
    if (id != req.params.id) {
      return res.status(400).send({ message: "Usage /[id]"});
    }
  }

  /* If identityId requested is -1, this is the "Unknown" identity
   * where all unmapped faces live. */
  if (id === -1) {
    const unknownIdentity = await getUnknownIdentity()
    return res.status(200).json([ unknownIdentity ]);
  }

  const filter = id ? "WHERE identities.id=:id " : "";

  const identities = await photoDB.sequelize.query("SELECT " +
    "identities.*," +
    "GROUP_CONCAT(faces.id) AS relatedFaceIds," +
    "GROUP_CONCAT(faces.descriptorId) AS relatedFaceDescriptorIds," +
    "GROUP_CONCAT(faces.photoId) AS relatedFacePhotoIds " +
    "FROM identities " +
    "LEFT JOIN faces ON identities.id=faces.identityId " +
    filter +
    "GROUP BY identities.id", {
    replacements: { id },
    type: photoDB.Sequelize.QueryTypes.SELECT,
    raw: true
  });

  await Promise.map(identities, async (identity) => {
    [ 'firstName', 'middleName', 'lastName' ].forEach(key => {
      if (!identity[key]) {
        identity[key] = '';
      }
    });
    identity.identityId = identity.id;

    if (!identity.relatedFaceIds) {
      identity.relatedFaces = [];
    } else {
      const relatedFaces = identity.relatedFaceIds.split(","),
        relatedFacePhotos = identity.relatedFacePhotoIds.split(",");

      let descriptors = await photoDB.sequelize.query(
        `SELECT descriptors FROM facedescriptors WHERE id in (:ids)`, {
          replacements: {
            ids: identity.relatedFaceDescriptorIds.split(',')
          },
          type: photoDB.Sequelize.QueryTypes.SELECT,
          raw: true
        }
      );
     
      descriptors = descriptors.map(entry => entry.descriptors);

      identity.relatedFaces = relatedFaces.map((faceId, index) => {
        const distance = euclideanDistance(
          descriptors[index],
          identity.descriptors
        );

        return {
          identityId: identity.id,
          faceId,
          photoId: relatedFacePhotos[index],
          distance
        };
      });
    }

    if (identity.relatedFaces.length === 0) {
      identity.relatedFaces.push({
        faceId: -1,
        photoId: -1,
        identityId: identity.id,
        distance: 0,
        faceConfidence: 0
      });
    }
   
    identity
      .relatedFaces
      .sort((A, B) => {
        return A.distance - B.distance;
      });

    /* If no filter was specified, only return the best face for
     * the identity */
    if (!filter) {
      identity.relatedFaces = [ identity.relatedFaces[0] ];
    }

    delete identity.id;
    delete identity.descriptors;
    delete identity.relatedFaceIds;
    delete identity.relatedFacePhotoIds;
    delete identity.relatedFaceDescriptorIds;
    delete identity.relatedIdentityDescriptors;
  });

  /* If no ID was provided (so no 'filter') then this call is returning
   * a list of all identities -- we create a fake identity for all
   * unlabeled faces */
  if (!filter) {
    const unknownIdentity = await getUnknownIdentity(1) 
    identities.push(unknownIdentity);
  }

  return res.status(200).json(identities);
});

module.exports = router;