/* global cachedStyles: true */
'use strict';

const RX_NAMESPACE = new RegExp([/[\s\r\n]*/,
  /(@namespace[\s\r\n]+(?:[^\s\r\n]+[\s\r\n]+)?url\(http:\/\/.*?\);)/,
  /[\s\r\n]*/].map(rx => rx.source).join(''), 'g');
const RX_CSS_COMMENTS = /\/\*[\s\S]*?\*\//g;
const SLOPPY_REGEXP_PREFIX = '\0';

// Note, only 'var'-declared variables are visible from another extension page
// eslint-disable-next-line no-var
var cachedStyles = {
  list: null,
  byId: new Map(),
  filters: new Map(),
  regexps: new Map(),
  urlDomains: new Map(),
  emptyCode: new Map(), // entire code is comments/whitespace/@namespace
  mutex: {
    inProgress: false,
    onDone: [],
  },
};


function getDatabase(ready, error) {
  const dbOpenRequest = window.indexedDB.open('stylish', 2);
  dbOpenRequest.onsuccess = event => {
    ready(event.target.result);
  };
  dbOpenRequest.onerror = event => {
    console.warn(event.target.errorCode);
    if (error) {
      error(event);
    }
  };
  dbOpenRequest.onupgradeneeded = event => {
    if (event.oldVersion == 0) {
      event.target.result.createObjectStore('styles', {
        keyPath: 'id',
        autoIncrement: true,
      });
    }
  };
}


function getStyles(options, callback) {
  if (cachedStyles.list) {
    callback(filterStyles(options));
    return;
  }
  if (cachedStyles.mutex.inProgress) {
    cachedStyles.mutex.onDone.push({options, callback});
    return;
  }
  cachedStyles.mutex.inProgress = true;

  //const t0 = performance.now();
  getDatabase(db => {
    const tx = db.transaction(['styles'], 'readonly');
    const os = tx.objectStore('styles');
    os.getAll().onsuccess = event => {
      cachedStyles.list = event.target.result || [];
      cachedStyles.byId.clear();
      for (const style of cachedStyles.list) {
        cachedStyles.byId.set(style.id, style);
        compileStyleRegExps({style});
      }
      //console.debug('%s getStyles %s, invoking cached callbacks: %o', (performance.now() - t0).toFixed(1), JSON.stringify(options), cachedStyles.mutex.onDone.map(e => JSON.stringify(e.options))); // eslint-disable-line max-len
      callback(filterStyles(options));

      cachedStyles.mutex.inProgress = false;
      for (const {options, callback} of cachedStyles.mutex.onDone) {
        callback(filterStyles(options));
      }
      cachedStyles.mutex.onDone = [];
    };
  }, null);
}


function filterStyles({
  enabled,
  url = null,
  id = null,
  matchUrl = null,
  asHash = null,
  strictRegexp = true, // used by the popup to detect bad regexps
} = {}) {
  //const t0 = performance.now();
  enabled = fixBoolean(enabled);
  id = id === null ? null : Number(id);

  if (enabled === null
  && url === null
  && id === null
  && matchUrl === null
  && asHash != true) {
    //console.debug('%c%s filterStyles SKIPPED LOOP %s', 'color:gray', (performance.now() - t0).toFixed(1), enabled, id, asHash, strictRegexp, matchUrl); // eslint-disable-line max-len
    return cachedStyles.list;
  }
  // silence the inapplicable warning for async code
  // eslint-disable-next-line no-use-before-define
  const disableAll = asHash && prefs.get('disableAll', false);

  // add \t after url to prevent collisions (not sure it can actually happen though)
  const cacheKey = ' ' + enabled + url + '\t' + id + matchUrl + '\t' + asHash + strictRegexp;
  const cached = cachedStyles.filters.get(cacheKey);
  if (cached) {
    //console.debug('%c%s filterStyles REUSED RESPONSE %s', 'color:gray', (performance.now() - t0).toFixed(1), enabled, id, asHash, strictRegexp, matchUrl); // eslint-disable-line max-len
    cached.hits++;
    cached.lastHit = Date.now();

    return asHash
      ? Object.assign({disableAll}, cached.styles)
      : cached.styles;
  }

  if (matchUrl && !cachedStyles.urlDomains.has(matchUrl)) {
    cachedStyles.urlDomains.set(matchUrl, getDomains(matchUrl));
    for (let i = cachedStyles.urlDomains.size - 100; i > 0; i--) {
      const firstKey = cachedStyles.urlDomains.keys().next().value;
      cachedStyles.urlDomains.delete(firstKey);
    }
  }

  const styles = id === null
    ? cachedStyles.list
    : [cachedStyles.byId.get(id)];
  const filtered = asHash ? {} : [];
  if (!styles) {
    // may happen when users [accidentally] reopen an old URL
    // of edit.html with a non-existent style id parameter
    return filtered;
  }
  const needSections = asHash || matchUrl !== null;

  for (let i = 0, style; (style = styles[i]); i++) {
    if ((enabled === null || style.enabled == enabled)
      && (url === null || style.url == url)
      && (id === null || style.id == id)) {
      const sections = needSections &&
        getApplicableSections({style, matchUrl, strictRegexp, stopOnFirst: !asHash});
      if (asHash) {
        if (sections.length) {
          filtered[style.id] = sections;
        }
      } else if (matchUrl === null || sections.length) {
        filtered.push(style);
      }
    }
  }
  //console.debug('%s filterStyles %s', (performance.now() - t0).toFixed(1), enabled, id, asHash, strictRegexp, matchUrl); // eslint-disable-line max-len
  cachedStyles.filters.set(cacheKey, {
    styles: filtered,
    lastHit: Date.now(),
    hits: 1,
  });
  if (cachedStyles.filters.size > 10000) {
    cleanupCachedFilters();
  }
  return asHash
    ? Object.assign({disableAll}, filtered)
    : filtered;
}


function saveStyle(style) {
  return new Promise(resolve => {
    getDatabase(db => {
      const tx = db.transaction(['styles'], 'readwrite');
      const os = tx.objectStore('styles');

      const id = style.id !== undefined && style.id !== null ? Number(style.id) : null;
      const reason = style.reason;
      const notify = style.notify !== false;
      delete style.method;
      delete style.reason;
      delete style.notify;
      if (!style.name) {
        delete style.name;
      }

      // Update
      if (id !== null) {
        style.id = id;
        os.get(id).onsuccess = eventGet => {
          const existed = Boolean(eventGet.target.result);
          const oldStyle = Object.assign({}, eventGet.target.result);
          const codeIsUpdated = 'sections' in style && !styleSectionsEqual(style, oldStyle);
          style = Object.assign(oldStyle, style);
          addMissingStyleTargets(style);
          os.put(style).onsuccess = eventPut => {
            style.id = style.id || eventPut.target.result;
            invalidateCache(notify, existed ? {updated: style} : {added: style});
            compileStyleRegExps({style});
            if (notify) {
              notifyAllTabs({
                method: existed ? 'styleUpdated' : 'styleAdded',
                style, codeIsUpdated, reason,
              });
            }
            resolve(style);
          };
        };
        return;
      }

      // Create
      delete style.id;
      style = Object.assign({
        // Set optional things if they're undefined
        enabled: true,
        updateUrl: null,
        md5Url: null,
        url: null,
        originalMd5: null,
      }, style);
      addMissingStyleTargets(style);
      os.add(style).onsuccess = event => {
        // Give it the ID that was generated
        style.id = event.target.result;
        invalidateCache(notify, {added: style});
        compileStyleRegExps({style});
        if (notify) {
          notifyAllTabs({method: 'styleAdded', style, reason});
        }
        resolve(style);
      };
    });
  });
}


function deleteStyle({id, notify = true}) {
  return new Promise(resolve =>
    getDatabase(db => {
      const tx = db.transaction(['styles'], 'readwrite');
      const os = tx.objectStore('styles');
      os.delete(Number(id)).onsuccess = () => {
        invalidateCache(notify, {deletedId: id});
        if (notify) {
          notifyAllTabs({method: 'styleDeleted', id});
        }
        resolve(id);
      };
    }));
}


function getApplicableSections({style, matchUrl, strictRegexp = true, stopOnFirst}) {
  //let t0 = 0;
  const sections = [];
  checkingSections:
  for (const section of style.sections) {
    andCollect:
    do {
      // only http, https, file, ftp, and chrome-extension://OWN_EXTENSION_ID allowed
      if (!matchUrl.startsWith('http')
      && !matchUrl.startsWith('ftp')
      && !matchUrl.startsWith('file')
      && !matchUrl.startsWith(URLS.ownOrigin)) {
        continue checkingSections;
      }
      if (section.urls.length == 0
      && section.domains.length == 0
      && section.urlPrefixes.length == 0
      && section.regexps.length == 0) {
        break andCollect;
      }
      if (section.urls.indexOf(matchUrl) != -1) {
        break andCollect;
      }
      for (const urlPrefix of section.urlPrefixes) {
        if (matchUrl.startsWith(urlPrefix)) {
          break andCollect;
        }
      }
      if (section.domains.length) {
        const urlDomains = cachedStyles.urlDomains.get(matchUrl) || getDomains(matchUrl);
        for (const domain of urlDomains) {
          if (section.domains.indexOf(domain) != -1) {
            break andCollect;
          }
        }
      }
      for (const regexp of section.regexps) {
        for (let pass = 1; pass <= (strictRegexp ? 1 : 2); pass++) {
          const cacheKey = pass == 1 ? regexp : SLOPPY_REGEXP_PREFIX + regexp;
          let rx = cachedStyles.regexps.get(cacheKey);
          if (rx == false) {
            // invalid regexp
            break;
          }
          if (!rx) {
            const anchored = pass == 1 ? '^(?:' + regexp + ')$' : '^' + regexp + '$';
            rx = tryRegExp(anchored);
            cachedStyles.regexps.set(cacheKey, rx || false);
            if (!rx) {
              // invalid regexp
              break;
            }
          }
          if (rx.test(matchUrl)) {
            break andCollect;
          }
        }
      }
      continue checkingSections;
    } while (0);
    // Collect the section if not empty or namespace-only.
    // We don't check long code as it's slow both for emptyCode declared as Object
    // and as Map in case the string is not the same reference used to add the item
    //const t0start = performance.now();
    const code = section.code;
    let isEmpty = code !== null && code.length < 1000 && cachedStyles.emptyCode.get(code);
    if (isEmpty === undefined) {
      isEmpty = !code || !code.trim()
        || code.indexOf('@namespace') >= 0
        && code.replace(RX_CSS_COMMENTS, '').replace(RX_NAMESPACE, '').trim() == '';
      cachedStyles.emptyCode.set(code, isEmpty);
    }
    //t0 += performance.now() - t0start;
    if (!isEmpty) {
      sections.push(section);
      if (stopOnFirst) {
        //t0 >= 0.1 && console.debug('%s emptyCode', t0.toFixed(1)); // eslint-disable-line no-unused-expressions
        return sections;
      }
    }
  }
  //t0 >= 0.1 && console.debug('%s emptyCode', t0.toFixed(1)); // eslint-disable-line no-unused-expressions
  return sections;
}


function styleSectionsEqual(styleA, styleB) {
  if (!styleA.sections || !styleB.sections) {
    return undefined;
  }
  if (styleA.sections.length != styleB.sections.length) {
    return false;
  }
  const propNames = ['code', 'urlPrefixes', 'urls', 'domains', 'regexps'];
  const typeBcaches = [];
  checkingEveryInA:
  for (const sectionA of styleA.sections) {
    const typeAcache = new Map();
    for (const name of propNames) {
      typeAcache.set(name, getType(sectionA[name]));
    }
    lookingForDupeInB:
    for (let i = 0, sectionB; (sectionB = styleB.sections[i]); i++) {
      const typeBcache = typeBcaches[i] = typeBcaches[i] || new Map();
      comparingProps:
      for (const name of propNames) {
        const propA = sectionA[name];
        const typeA = typeAcache.get(name);
        const propB = sectionB[name];
        let typeB = typeBcache.get(name);
        if (!typeB) {
          typeB = getType(propB);
          typeBcache.set(name, typeB);
        }
        if (typeA != typeB) {
          const bothEmptyOrUndefined =
            (typeA == 'undefined' || (typeA == 'array' && propA.length == 0)) &&
            (typeB == 'undefined' || (typeB == 'array' && propB.length == 0));
          if (bothEmptyOrUndefined) {
            continue comparingProps;
          } else {
            continue lookingForDupeInB;
          }
        }
        if (typeA == 'undefined') {
          continue comparingProps;
        }
        if (typeA == 'array') {
          if (propA.length != propB.length) {
            continue lookingForDupeInB;
          }
          for (const item of propA) {
            if (propB.indexOf(item) < 0) {
              continue lookingForDupeInB;
            }
          }
          continue comparingProps;
        }
        if (typeA == 'string' && propA != propB) {
          continue lookingForDupeInB;
        }
      }
      // dupe found
      continue checkingEveryInA;
    }
    // dupe not found
    return false;
  }
  return true;
}


function compileStyleRegExps({style, compileAll}) {
  const t0 = performance.now();
  for (const section of style.sections || []) {
    for (const regexp of section.regexps) {
      for (let pass = 1; pass <= (compileAll ? 2 : 1); pass++) {
        const cacheKey = pass == 1 ? regexp : SLOPPY_REGEXP_PREFIX + regexp;
        if (cachedStyles.regexps.has(cacheKey)) {
          continue;
        }
        // according to CSS4 @document specification the entire URL must match
        const anchored = pass == 1 ? '^(?:' + regexp + ')$' : '^' + regexp + '$';
        const rx = tryRegExp(anchored);
        cachedStyles.regexps.set(cacheKey, rx || false);
        if (!compileAll && performance.now() - t0 > 100) {
          return;
        }
      }
    }
  }
}


function invalidateCache(andNotify, {added, updated, deletedId} = {}) {
  // prevent double-add on echoed invalidation
  const cached = added && cachedStyles.byId.get(added.id);
  if (cached) {
    return;
  }
  if (andNotify) {
    chrome.runtime.sendMessage({method: 'invalidateCache', added, updated, deletedId});
  }
  if (!cachedStyles.list) {
    return;
  }
  if (updated) {
    const cached = cachedStyles.byId.get(updated.id);
    if (cached) {
      Object.assign(cached, updated);
      //console.debug('cache: updated', updated);
    }
    cachedStyles.filters.clear();
    return;
  }
  if (added) {
    cachedStyles.list.push(added);
    cachedStyles.byId.set(added.id, added);
    //console.debug('cache: added', added);
    cachedStyles.filters.clear();
    return;
  }
  if (deletedId != undefined) {
    const deletedStyle = (cachedStyles.byId.get(deletedId) || {}).style;
    if (deletedStyle) {
      const cachedIndex = cachedStyles.list.indexOf(deletedStyle);
      cachedStyles.list.splice(cachedIndex, 1);
      cachedStyles.byId.delete(deletedId);
      //console.debug('cache: deleted', deletedStyle);
      cachedStyles.filters.clear();
      return;
    }
  }
  cachedStyles.list = null;
  //console.debug('cache cleared');
  cachedStyles.filters.clear();
}


function cleanupCachedFilters({force = false} = {}) {
  if (!force) {
    // sliding timer for 1 second
    clearTimeout(cleanupCachedFilters.timeout);
    cleanupCachedFilters.timeout = setTimeout(cleanupCachedFilters, 1000, {force: true});
    return;
  }
  const size = cachedStyles.filters.size;
  const oldestHit = cachedStyles.filters.values().next().value.lastHit;
  const now = Date.now();
  const timeSpan = now - oldestHit;
  const recencyWeight = 5 / size;
  const hitWeight = 1 / 4; // we make ~4 hits per URL
  const lastHitWeight = 10;
  // delete the oldest 10%
  [...cachedStyles.filters.entries()]
    .map(([id, v], index) => ({
      id,
      weight:
        index * recencyWeight +
        v.hits * hitWeight +
        (v.lastHit - oldestHit) / timeSpan * lastHitWeight,
    }))
    .sort((a, b) => a.weight - b.weight)
    .slice(0, size / 10 + 1)
    .forEach(({id}) => cachedStyles.filters.delete(id));
  cleanupCachedFilters.timeout = 0;
}


function addMissingStyleTargets(style) {
  style.sections = (style.sections || []).map(section =>
    Object.assign({
      urls: [],
      urlPrefixes: [],
      domains: [],
      regexps: [],
    }, section)
  );
}


function reportError(...args) {
  for (const arg of args) {
    if ('message' in arg) {
      console.log(arg.message);
    }
  }
}


function fixBoolean(b) {
  if (typeof b != 'undefined') {
    return b != 'false';
  }
  return null;
}


function getDomains(url) {
  if (url.indexOf('file:') == 0) {
    return [];
  }
  let d = /.*?:\/*([^/:]+)/.exec(url)[1];
  const domains = [d];
  while (d.indexOf('.') != -1) {
    d = d.substring(d.indexOf('.') + 1);
    domains.push(d);
  }
  return domains;
}


function getType(o) {
  if (typeof o == 'undefined' || typeof o == 'string') {
    return typeof o;
  }
  // with the persistent cachedStyles the Array reference is usually different
  // so let's check for e.g. type of 'every' which is only present on arrays
  // (in the context of our extension)
  if (o instanceof Array || typeof o.every == 'function') {
    return 'array';
  }
  console.warn('Unsupported type:', o);
  return 'undefined';
}