local app = require("lapis").Application()

local db = require("lapis.db")
local constants = require("constants")

local util = require("util")

local bcrypt = require("bcrypt")
local rand = require("openssl.rand")

local models = require("models")
local Users = models.Users
local Sessions = models.Sessions
local Avatars = models.Avatars

local function authenticate_user(user, password)
  return bcrypt.verify(password, user.password_hash)
end

local function create_session_key()
  return rand.bytes(16):gsub(".", function(c) return string.format("%02x", string.byte(c)) end)
end

local function create_session(user_id)
  local days = 30
  local expires_at = os.time() + (days * 24 * 60 * 60)

  return Sessions:create({
    key = create_session_key(),
    user_id = user_id,
    expires_at = expires_at,
  })
end

local function validate_password(password)
  if #password < 10 or password:match("%s") then
    return false
  end

  if #password > 255 then
    return false
  end

  local r = password:match("%u+") and
            password:match("%l+") and
            password:match("%d+") and
            password:match("%p+")
  return r ~= nil and true
end

local function validate_username(username)
  if #username < 3 or #username > 20 then
    return false
  end

  return username:match("^[%w_-]+$") and true
end

local function validate_url(url)
  return url:match('^https?://.+$') and true
end

app:get("user", "/:username", function(self)
  local user = Users:find({username = self.params.username})
  if not user then
    return {status = 404}
  end

  if self.session.flash ~= nil and self.session.flash.just_logged_in then
    self.just_logged_in = true
    self.session.flash = {}
  end

  -- local me = validate_session(self.session.session_key) or TransientUser
  local me = util.get_logged_in_user(self) or util.TransientUser
  self.user = user
  self.me = me

  self.user_is_me = me.id == user.id

  if user.permission == constants.PermissionLevel.GUEST then
    if not (self.user_is_me or me:is_mod()) then
      return {status = 404}
    end
  end

  self.page_title = user.username

  return {render = "user.user"}
end)

app:post("user_delete", "/:username/delete", function(self)
  local me = util.get_logged_in_user(self)
  if me == nil then
    self.session.flash = {error = "You must be logged in to perform this action."}
    return {redirect_to = self:url_for("user_login")}
  end
  local target_user = Users:find({username = self.params.username})
  if not me:is_mod() then
    if me.id ~= target_user.id then
      return {redirect_to = self:url_for("user", {username = self.params.username})}
    end
    
    if not authenticate_user(target_user, self.params.password) then
      self.session.flash = {error = "The password you entered is incorrect."}
      return {redirect_to = self:url_for("user_delete_confirm", {username = me.username})}
    end
    
    util.transfer_and_delete_user(target_user)
    self.session.flash = {error = "Your account has been added to the deletion queue."}
    return {redirect_to = self:url_for("user_signup")}
  else
    if target_user.permission >= me.permission then
      self.session.flash = {error = "You can not delete another moderator."}
      return {redirect_to = self:url_for("user", {username = me.username})}
    end
  end
end)

app:get("user_delete_confirm", "/:username/delete_confirm", function(self)
  local me = util.get_logged_in_user(self)
  if me == nil then
    self.session.flash = {error = "You must be logged in to perform this action."}
    return {redirect_to = self:url_for("user_login")}
  end
  local target_user = Users:find({username = self.params.username})
  if me.id ~= target_user.id then
    return {redirect_to = self:url_for("user", {username = self.params.username})}
  end
  if self.session.flash then
    self.err = self.session.flash.error
    self.session.flash = {}
  end
  self.me = target_user
  self.page_title = "confirm deletion"

  return {render = "user.delete_confirm"}
end)

app:post("user_clear_avatar", "/:username/clear_avatar", function(self)
  local me = util.get_logged_in_user(self)
  if me == nil then
    self.session.flash = {error = "You must be logged in to perform this action."}
    return {redirect_to = self:url_for("user_login")}
  end
  local target_user = Users:find({username = self.params.username})
  if me.id ~= target_user.id then
    return {redirect_to = self:url_for("user", {username = self.params.username})}
  end
  target_user:update({
    avatar_id = db.NULL,
  })
  self.session.flash = {success = true, msg = "Avatar cleared."}
  return {redirect_to = self:url_for("user_settings", {username = self.params.username})}
end)

app:post("user_set_avatar", "/:username/set_avatar", function(self)
  local me = util.get_logged_in_user(self)
  if me == nil then
    self.session.flash = {error = "You must be logged in to perform this action."}
    return {redirect_to = self:url_for("user_login")}
  end
  local target_user = Users:find({username = self.params.username})
  if me.id ~= target_user.id then
    return {redirect_to = self:url_for("user", {username = self.params.username})}
  end
  local file = self.params.avatar
  if not file then
    self.session.flash = {error = "Something went wrong. Try again later."}
    return {redirect_to = self:url_for("user_settings", {username = self.params.username})}
  end
  local time = os.time()
  local filename = "u" .. target_user.id .. "d" .. time .. ".webp"
  local proxied_filename = "/avatars/" .. filename
  local save_path = "static" .. proxied_filename
  local res = util.validate_and_create_image(file.content, save_path)
  if not res then
    self.session.flash = {error = "Something went wrong. Try again later."}
    return {redirect_to = self:url_for("user_settings", {username = self.params.username})}
  end

  self.session.flash = {success = true, msg = "Avatar updated."}
  local avatar = Avatars:create({
    file_path = proxied_filename,
    uploaded_at = time,
  })

  target_user:update({
    avatar_id = avatar.id
  })

  return {redirect_to = self:url_for("user_settings", {username = self.params.username})}
end)

app:get("user_settings", "/:username/settings", function(self)
  local me = util.get_logged_in_user(self)
  if me == nil then
    self.session.flash = {error = "You must be logged in to perform this action."}
    return {redirect_to = self:url_for("user_login")}
  end
  local target_user = Users:find({username = self.params.username})
  if me.id ~= target_user.id then
    return {redirect_to = self:url_for("user", {username = self.params.username})}
  end
  if self.session.flash then
    local flash = self.session.flash
    self.session.flash = nil
    if flash.success then
      self.flash_msg = flash.msg
    elseif flash.error then
      self.flash_msg = flash.error
    end
  end
  self.me = target_user
  self.page_title = "settings"

  return {render = "user.settings"}
end)

app:post("user_settings", "/:username/settings", function(self)
  local me = util.get_logged_in_user(self)
  if me == nil then
    self.session.flash = {error = "You must be logged in to perform this action."}
    return {redirect_to = self:url_for("user_login")}
  end
  local target_user = Users:find({username = self.params.username})
  if me.id ~= target_user.id then
    return {redirect_to = self:url_for("user", {username = self.params.username})}
  end

  local status = self.params.status:sub(1, 100)

  target_user:update({
    status = status,
  })
  self.session.flash = {
    success = true,
    msg = "Settings updated."
  }
  return {redirect_to = self:url_for("user_settings", {username = self.params.username})}
end)

app:get("user_login", "/login", function(self)
  if self.session.session_key then
    local user = util.get_logged_in_user(self)
    if user ~= nil then
      return {redirect_to = self:url_for("user", {username = user.username})}
    end
  end

  if self.session.flash then
    self.err = self.session.flash.error
    self.session.flash = {}
  end

  self.page_title = "log in"

  return {render = "user.login"}
end)

app:post("user_login", "/login", function(self)
  if self.session.session_key then
    local user = util.get_logged_in_user(self)
    if user ~= nil then
      return {redirect_to = self:url_for("user", {username = user.username})}
    end
  end
  local username = self.params.username
  local password = self.params.password
  local user = Users:find({username = username})
  if not user then
    self.session.flash = {error = "Invalid username or password"}
    return {redirect_to = self:url_for("user_login")}
  end
  if user.permission == constants.PermissionLevel.SYSTEM then
    self.session.flash = {error = "Invalid username or password"}
    return {redirect_to = self:url_for("user_login")}
  end
  if not authenticate_user(user, password) then
    self.session.flash = {error = "Invalid username or password"}
    return {redirect_to = self:url_for("user_login")}
  end
  local session = create_session(user.id)
  self.session.flash = {just_logged_in = true}
  self.session.session_key = session.key
  return {redirect_to = self:url_for("user", {username = username})}
end)

app:get("user_signup", "/signup", function(self)
  if self.session.session_key then
    local user = util.get_logged_in_user(self)
    if user ~= nil then
      return {redirect_to = self:url_for("user", {username = user.username})}
    end
  end
  if self.session.flash then
    self.err = self.session.flash.error
    self.session.flash = {}
  end

  self.page_title = "sign up"

  return {render = "user.signup"}
end)

app:post("user_signup", "/signup", function(self)
  if self.session.session_key then
    local user = util.get_logged_in_user(self)
    if user ~= nil then
      return {redirect_to = self:url_for("user", {username = user.username})}
    end
  end

  local username = self.params.username
  local password = self.params.password
  local password2 = self.params.password2
  local user = Users:find({username = username})
  if user then
    self.session.flash = {error = "Username '" .. username .. "' is already taken."}
    return {redirect_to = self:url_for("user_signup")}
  end

  if not validate_username(username) then
    self.session.flash = {error = "Username must be 3-20 characters with only upper and lowercase letters, hyphens, and underscores."}
    return {redirect_to = self:url_for("user_signup")}
  end

  if not validate_password(password) then
    self.session.flash = {error = "Password must be 10+ chars with: 1 uppercase, 1 lowercase, 1 number, 1 special char, and no spaces."}
    return {redirect_to = self:url_for("user_signup")}
  end

  if password ~= password2 then
    self.session.flash = {error = "Passwords do not match."}
    return {redirect_to = self:url_for("user_signup")}
  end

  local new_user = Users:create({
    username = username,
    password_hash = bcrypt.digest(password, constants.BCRYPT_ROUNDS),
    permission = constants.PermissionLevel.GUEST,
  })

  local session = create_session(new_user.id)
  self.session.flash = {just_logged_in = true}
  self.session.session_key = session.key
  return {redirect_to = self:url_for("user", {username = username})}
end)

app:post("user_logout", "/logout", function (self)
  local user = util.get_logged_in_user(self)
  if not user then
    return {redirect_to = self:url_for("user_login")}
  end

  local session = Sessions:find({key = self.session.session_key})
  session:delete()
  return {redirect_to = self:url_for("user_login")}
end)

app:post("confirm_user", "/confirm_user/:user_id", function (self)
  local user = util.get_logged_in_user(self)
  if not user then
    return {status = 403}
  end
  if not user:is_mod() then
    return {status = 403}
  end
  local target_user = Users:find(self.params.user_id)
  if not target_user then
    return {status = 404}
  end
  if target_user.permission > constants.PermissionLevel.GUEST then
    return {status = 404}
  end

  target_user:update({permission = constants.PermissionLevel.USER, confirmed_on = os.time()})
  return {redirect_to = self:url_for("user", {username = target_user.username})}
end)

app:post("mod_user", "/mod_user/:user_id", function(self)
  local user = util.get_logged_in_user(self)
  if not user then
    return {status = 403}
  end
  if not user:is_admin() then
    return {status = 403}
  end
  local target_user = Users:find(self.params.user_id)
  if not target_user then
    return {status = 404}
  end
  if target_user:is_mod() then
    return {status = 404}
  end
  
  target_user:update({permission = constants.PermissionLevel.MODERATOR})
  return {redirect_to = self:url_for("user", {username = target_user.username})}
end)

app:post("demod_user", "/demod_user/:user_id", function(self)
  local user = util.get_logged_in_user(self)
  if not user then
    return {status = 403}
  end
  if not user:is_admin() then
    return {status = 403}
  end
  local target_user = Users:find(self.params.user_id)
  if not target_user then
    return {status = 404}
  end
  if not target_user:is_mod() then
    return {status = 404}
  end
  
  target_user:update({permission = constants.PermissionLevel.USER})
  return {redirect_to = self:url_for("user", {username = target_user.username})}
end)

app:post("guest_user", "/guest_user/:user_id", function(self)
  local user = util.get_logged_in_user(self)
  if not user then
    return {status = 403}
  end
  if not user:is_mod() then
    return {status = 403}
  end
  local target_user = Users:find(self.params.user_id)
  if not target_user then
    return {status = 404}
  end
  if target_user:is_mod() then
    return {status = 404}
  end
  
  target_user:update({permission = constants.PermissionLevel.GUEST})
  return {redirect_to = self:url_for("user", {username = target_user.username})}
end)

return app