root = exports ? window

RegexpCache =
  cache: {}
  get: (pattern) ->
    if regexp = @cache[pattern]
      regexp
    else
      @cache[pattern] = new RegExp("^" + pattern.replace(/\*/g, ".*") + "$")

# The Exclusions class manages the exclusion rule setting.
# An exclusion is an object with two attributes: pattern and passKeys.
# The exclusions are an array of such objects (because the order matters).

root.Exclusions = Exclusions =

  rules: Settings.get("exclusionRules")

  # Return the first exclusion rule matching the URL, or null.
  getRule: (url) ->
    for rule in @rules
      return rule if url.match(RegexpCache.get(rule.pattern))
    return null

  setRules: (rules) ->
    # Callers map a rule to null to have it deleted, and rules without a pattern are useless.
    @rules = rules.filter (rule) -> rule and rule.pattern
    Settings.set("exclusionRules", @rules)

  postUpdateHook: (rules) ->
    @rules = rules

  # Update an existing rule or add a new rule.
  updateOrAdd: (newRule) ->
    seen = false
    @rules.push(newRule)
    @setRules @rules.map (rule) ->
      if rule.pattern == newRule.pattern
        if seen then null else seen = newRule
      else
        rule

  remove: (pattern) ->
    @setRules(@rules.filter((rule) -> rule and rule.pattern != pattern))

# Development and debug only.
# Enable this (temporarily) to restore legacy exclusion rules from backup.
if false and Settings.has("excludedUrlsBackup")
  Settings.clear("exclusionRules")
  Settings.set("excludedUrls", Settings.get("excludedUrlsBackup"))

if not Settings.has("exclusionRules") and Settings.has("excludedUrls")
  # Migration from the legacy representation of exclusion rules.
  #
  # In Vimium 1.45 and in github/master on 27 August, 2014, exclusion rules are represented by the setting:
  #   excludedUrls: "http*://www.google.com/reader/*\nhttp*://mail.google.com/* jk"
  #
  # The new (equivalent) settings is:
  #   exclusionRules: [ { pattern: "http*://www.google.com/reader/*", passKeys: "" }, { pattern: "http*://mail.google.com/*", passKeys: "jk" } ]

  parseLegacyRules = (lines) ->
    for line in lines.trim().split("\n").map((line) -> line.trim())
      if line.length and line.indexOf("#") != 0 and line.indexOf('"') != 0
        parse = line.split(/\s+/)
        { pattern: parse[0], passKeys: parse[1..].join("") }

  Exclusions.setRules(parseLegacyRules(Settings.get("excludedUrls")))
  # We'll keep a backup of the "excludedUrls" setting, just in case.
  Settings.set("excludedUrlsBackup", Settings.get("excludedUrls")) if not Settings.has("excludedUrlsBackup")
  Settings.clear("excludedUrls")