'use strict';

var PromiseA;
try {
  PromiseA = require('bluebird');
} catch(e) {
  PromiseA = global.Promise;
}
var promisify = PromiseA.promisify || require('util').promisify;
var fs = {
  existsSync: require('fs').existsSync
, mkdirSync: require('fs').mkdirSync
, readdirAsync: promisify(require('fs').readdir)
, writeFileAsync: promisify(require('fs').writeFile)
, unlinkAsync: promisify(require('fs').unlink)
};
var path = require('path');

module.exports = {
  create: function (loc/*, opts*/) {
    var oauth3dir;
    if (!loc.pathname) {
      loc.pathname = require('os').hostname();
      oauth3dir = path.join(loc.pathname, '.config/oauth3.org');
    } else {
      oauth3dir = path.join(loc.pathname, 'oauth3.org', 'v1');
    }
    var sessionsdir = path.join(oauth3dir, 'sessions');
    var directivesdir = path.join(oauth3dir, 'directives');
    var metadir = path.join(oauth3dir, 'meta');

    // We can reasonably assume the existence of the home directory, but we can't assume
    // that there will already be a `.oauth3` directory or anything inside of it.
    if (!fs.existsSync(path.join(oauth3dir, '..'))) {
      fs.mkdirSync(path.join(oauth3dir, '..'));
    }
    if (!fs.existsSync(oauth3dir)) {
      fs.mkdirSync(oauth3dir);
    }
    if (!fs.existsSync(directivesdir)) {
      fs.mkdirSync(directivesdir);
    }
    if (!fs.existsSync(sessionsdir)) {
      fs.mkdirSync(sessionsdir);
    }
    if (!fs.existsSync(metadir)) {
      fs.mkdirSync(metadir);
    }

    var OAUTH3 = {};
    OAUTH3.directives = {
      all: function () {
        return fs.readdirAsync(directivesdir).then(function (nodes) {
          return nodes.map(function (node) {
            try {
              return require(path.join(directivesdir, node));
            } catch(e) {
              return null;
            }
          }).filter(Boolean);
        });
      }
    , get: function (providerUri) {
        // TODO make safe
        try {
          return require(path.join(directivesdir, providerUri + '.json'));
        } catch(e) {
          return null;
        }
      }
    , set: function (providerUri, directives) {
        return fs.writeFileAsync(
          path.join(directivesdir, providerUri + '.json')
        , JSON.stringify(directives, null, 2)
        ).then(function () {
          return directives;
        });
      }
    , clear: function () {
        return fs.readdirAsync(directivesdir).then(function (nodes) {
          return PromiseA.all(nodes.map(function (node) {
            return fs.unlinkAsync(path.join(directivesdir, node)).then(function () { }, function () { });
          }));
        });
      }
    };
    OAUTH3.sessions = {
      all: function (providerUri) {
        return fs.readdirAsync(sessionsdir).then(function (nodes) {
          return nodes.map(function (node) {
            var result = require(path.join(sessionsdir, node));
            if (result.link) {
              return null;
            }
          }).filter(Boolean).filter(function (result) {
            if (!providerUri || providerUri === result.issuer) {
              return result;
            }
          });
        });
      }
    , get: function (providerUri, id) {
        var result;
        try {
          if (id) {
            return PromiseA.resolve(require(path.join(sessionsdir, providerUri + '.' + id + '.json')));
          }
          else {
            result = require(path.join(sessionsdir, providerUri + '.json'));
            // TODO make safer
            if (result.link && '/' !== result.link[0] && !/\.\./.test(result.link)) {
              result = require(path.join(sessionsdir, result.link));
            }
          }
        } catch(e) {
          return PromiseA.resolve(null);
        }
        return PromiseA.resolve(result);
      }
    , set: function (providerUri, session, id) {
        var p;

        if (id) {
          p = fs.writeFileAsync(path.join(sessionsdir, providerUri + '.' + id + '.json'), JSON.stringify(session, null, 2));
        }
        else {
          p = fs.writeFileAsync(path.join(sessionsdir, providerUri + '.json'), JSON.stringify(session, null, 2));
        }
        return p.then(function () {
          return session;
        });
      }
    , clear: function () {
        return fs.readdirAsync(sessionsdir).then(function (nodes) {
          return PromiseA.all(nodes.map(function (node) {
            return fs.unlinkAsync(path.join(sessionsdir, node));
          }));
        });
      }
    };
    OAUTH3.meta = {
      get: function (key) {
        // TODO make safe
        try {
          return PromiseA.resolve(require(path.join(metadir, key + '.json')));
        } catch(e) {
          return PromiseA.resolve(null);
        }
      }
    , set: function (key, value) {
        return fs.writeFileAsync(path.join(metadir, key + '.json'), JSON.stringify(value, null, 2)).then(function () {
          return value;
        });
      }
    };

    return OAUTH3;
  }
};