--[[
  ReAction bar state driver interface

--]]

-- local imports
local addonName, addonTable = ...
local ReAction = addonTable.ReAction
local L = ReAction.L
local _G = _G
local format = string.format
local InCombatLockdown = InCombatLockdown
local RegisterStateDriver = RegisterStateDriver

-- module declaration
local moduleID = "State"
local module = ReAction:NewModule( moduleID, "AceEvent-3.0" )

-- Utility --

-- traverse a table tree by key list and fetch the result or first nil
local function tfetch(t, ...)
  for i = 1, select('#', ...) do
    t = t and t[select(i, ...)]
  end
  return t
end

-- traverse a table tree by key list and build tree as necessary
local function tbuild(t, ...)
  for i = 1, select('#', ...) do
    local key = select(i, ...)
    if not t[key] then t[key] = { } end
    t = t[key]
  end
  return t
end

-- return a new array of keys of table 't', sorted by comparing 
-- sub-fields (obtained via tfetch) of the table values
local function fieldsort( t, ... )
  local r = { }
  for k in pairs(t) do
    table.insert(r,k)
  end
  local path = { ... }
  table.sort(r, function(lhs, rhs)
     local olhs = tfetch(t[lhs], unpack(path)) or 0
     local orhs = tfetch(t[rhs], unpack(path)) or 0
     return olhs < orhs
    end)
  return r
end


local ApplyStates, CleanupStates, SetProperty, GetProperty, RegisterProperty

-- PRIVATE --
do
  function GetProperty( bar, state, propname )
    return tfetch(module.db.profile.bars, bar:GetName(), "states", state, propname)
  end

  function SetProperty( bar, state, propname, value )
    local s = tbuild(module.db.profile.bars, bar:GetName(), "states", state)
    s[propname] = value
    bar:SetSecureStateData(state, propname, value)
  end

  function RegisterProperty( propname, snippet )
    for _, bar in ReAction:IterateBars() do
      if type(snippet) == "string" then
        bar:SetSecureStateExtension(propname,snippet)
      end
      ApplyStates(bar)
    end
  end

  function UnregisterProperty( propname )
    for _, bar in ReAction:IterateBars() do
      bar:SetSecureStateExtension(propname,nil)
      ApplyStates(bar)
    end
  end

  function ApplyStates( bar )
    local states = tfetch(module.db.profile.bars, bar:GetName(), "states")
    if states then
      bar:SetStateDriver(states)
    end
  end

  function CleanupStates( bar )
    bar:SetStateDriver(nil)
  end
end



-- module event handlers --

function module:OnInitialize()
  self.db = ReAction.db:RegisterNamespace( moduleID, 
    {
      profile = { 
        bars = { },
      }
    }
  )

  self:RegisterEvent("UPDATE_SHAPESHIFT_FORMS")

  ReAction:RegisterBarOptionGenerator(self, "GetBarOptions")

  ReAction.RegisterCallback(self, "OnCreateBar","OnRefreshBar")
  ReAction.RegisterCallback(self, "OnDestroyBar")
  ReAction.RegisterCallback(self, "OnRefreshBar")
  ReAction.RegisterCallback(self, "OnEraseBar")
  ReAction.RegisterCallback(self, "OnRenameBar")
end

function module:OnEnable()
  self:UPDATE_SHAPESHIFT_FORMS() -- it doesn't fire on a /reloadui
end

function module:UPDATE_SHAPESHIFT_FORMS()
  -- Re-parse the rules table according to the new form list.
  -- This happens both at initial login (after PLAYER_ENTERING_WORLD)
  -- as well as when gaining new abilities. 
  ReAction.Bar.InitRuleFormats()
  for _, bar in ReAction:IterateBars() do
    ApplyStates(bar)
  end
end

function module:OnRefreshBar(event, bar, name)
  local c = self.db.profile.bars[name]
  if c then
    ApplyStates(bar)
  end
end

function module:OnDestroyBar(event, bar, name)
  CleanupStates(bar)
end

function module:OnEraseBar(event, bar, name)
  self.db.profile.bars[name] = nil
end

function module:OnRenameBar(event, bar, oldname, newname)
  local bars = self.db.profile.bars
  bars[newname], bars[oldname] = bars[oldname], nil
end



-- Options --

local CreateBarOptions, RegisterPropertyOptions
do
  -- pre-sorted by the order they should appear in
  local rules = {
    --  rule       fields
    { "stance",  { {battle = L["Battle Stance"]}, {defensive = L["Defensive Stance"]}, {berserker = L["Berserker Stance"]} } },
    { "form",    { {caster = L["Caster Form"]}, {bear = L["Bear Form"]}, {cat = L["Cat Form"]}, {tree = L["Tree of Life"]}, {moonkin = L["Moonkin Form"]} } },
    { "stealth", { {stealth = L["Stealth"]}, {nostealth = L["No Stealth"]}, {shadowdance = L["Shadow Dance"]} } },
    { "shadow",  { {shadowform = L["Shadowform"]}, {noshadowform = L["No Shadowform"]} } },
    { "demon",   { {demon = L["Demon Form"]}, {nodemon = L["No Demon Form"]} } },
    { "pet",     { {pet = L["With Pet"]}, {nopet = L["Without Pet"]} } },
    { "target",  { {harm = L["Hostile Target"]}, {help = L["Friendly Target"]}, {notarget = L["No Target"]} } },
    { "focus",   { {focusharm = L["Hostile Focus"]}, {focushelp = L["Friendly Focus"]}, {nofocus = L["No Focus"]} } },
    { "possess", { {possess = L["Mind Control"]} } },
    { "vehicle", { {vehicle = L["In a Vehicle"]} } },
    { "group",   { {raid = L["Raid"]}, {party = L["Party"]}, {solo = L["Solo"]} } },
    { "combat",  { {combat = L["In Combat"]}, {nocombat = L["Out of Combat"]} } },
  }

  local ruleSelect = { }
  local ruleMap    = { }
  local optionMap  = setmetatable({},{__mode="k"})

  local pointTable = {
    NONE        = " ",
    CENTER      = L["Center"], 
    LEFT        = L["Left"],
    RIGHT       = L["Right"],
    TOP         = L["Top"],
    BOTTOM      = L["Bottom"],
    TOPLEFT     = L["Top Left"],
    TOPRIGHT    = L["Top Right"],
    BOTTOMLEFT  = L["Bottom Left"],
    BOTTOMRIGHT = L["Bottom Right"],
  }

  -- unpack rules table into ruleSelect and ruleMap
  for _, c in ipairs(rules) do
    local rule, fields = unpack(c)
    for _, field in ipairs(fields) do
      local key, label = next(field)
      table.insert(ruleSelect, label)
      table.insert(ruleMap, key)
    end
  end

  local stateOptions = {
    ordering = {
      name = L["Info"],
      order = 1,
      type = "group",
      args = {
        delete = {
          name = L["Delete this State"],
          order = -1,
          type = "execute",
          func = "DeleteState",
        },
        rename = {
          name = L["Name"],
          order = 1,
          type = "input",
          get  = "GetName",
          set  = "SetStateName",
          pattern = "^%w*$",
          usage = L["State names must be alphanumeric without spaces"],
        },
        ordering = {
          name = L["Evaluation Order"],
          desc = L["State transitions are evaluated in the order listed:\nMove a state up or down to change the order"],
          order = 2,
          type = "group",
          inline = true,
          args = {
            up = {
              name  = L["Up"],
              order = 1,
              type  = "execute",
              width = "half",
              func  = "MoveStateUp",
            },
            down = {
              name  = L["Down"],
              order = 2,
              type  = "execute",
              width = "half",
              func  = "MoveStateDown",
            }
          }
        }
      }
    },
    properties = {
      name = L["Properties"],
      order = 2,
      type = "group",
      args = { 
        desc = {
          name = L["Set the properties for the bar when in this state"],
          order = 1,
          type = "description"
        },
        hide = {
          name = L["Hide Bar"],
          order = 90,
          type = "toggle",
          set  = "SetProp",
          get  = "GetProp",
        },
        --[[ BROKEN
        keybindState = {
          name  = L["Override Keybinds"],
          desc  = L["Set this state to maintain its own set of keybinds which override the defaults when active"],
          order = 91,
          type  = "toggle",
          set   = "SetProp",
          get   = "GetProp",
        }, ]]
        position = {
          name  = L["Position"],
          order = 92,
          type  = "group",
          inline = true,
          args = {
            anchorEnable = {
              name  = L["Reposition"],
              order = 1,
              type  = "toggle",
              set   = "SetProp",
              get   = "GetProp",
            },
            anchorFrame = {
              name   = L["Anchor Frame"],
              order  = 2,
              type   = "select",
              values = "GetAnchorFrames",
              set    = "SetAnchorFrame",
              get    = "GetAnchorFrame",
              disabled = "GetAnchorDisabled",
              hidden = "GetAnchorDisabled",
            },
            anchorPoint = {
              name  = L["Point"],
              order = 3,
              type  = "select",
              values = pointTable,
              set   = "SetAnchorPointProp",
              get   = "GetAnchorPointProp",
              disabled = "GetAnchorDisabled",
              hidden = "GetAnchorDisabled",
            },
            anchorRelPoint = {
              name  = L["Relative Point"],
              order = 4,
              type  = "select",
              values = pointTable,
              set   = "SetAnchorPointProp",
              get   = "GetAnchorPointProp",
              disabled = "GetAnchorDisabled",
              hidden = "GetAnchorDisabled",
            },
            anchorX = {
              name  = L["X Offset"],
              order = 5,
              type  = "range",
              min   = -100,
              max   = 100,
              step  = 1,
              set   = "SetProp",
              get   = "GetProp",
              disabled = "GetAnchorDisabled",
              hidden = "GetAnchorDisabled",
            },
            anchorY = {
              name  = L["Y Offset"],
              order = 6,
              type  = "range",
              min   = -100,
              max   = 100,
              step  = 1,
              set   = "SetProp",
              get   = "GetProp",
              disabled = "GetAnchorDisabled",
              hidden = "GetAnchorDisabled",
            },
          },
        },
        scale = {
          name  = L["Scale"],
          order = 93,
          type  = "group",
          inline = true,
          args = {
            enableScale = {
              name  = L["Set New Scale"],
              order = 1,
              type  = "toggle",
              set   = "SetProp",
              get   = "GetProp",
            },
            scale = {
              name  = L["Scale"],
              order = 2,
              type  = "range",
              min   = 0.25,
              max   = 2.5,
              step  = 0.05,
              isPercent = true,
              set   = "SetProp",
              get   = "GetScale",
              disabled = "GetScaleDisabled",
              hidden = "GetScaleDisabled",
            },
          },
        },
        alpha = {
          name  = L["Transparency"],
          order = 94,
          type  = "group",
          inline = true,
          args = {
            enableAlpha = {
              name  = L["Set Transparency"],
              order = 1,
              type  = "toggle",
              set   = "SetProp",
              get   = "GetProp",
            },
            alpha = {
              name  = L["Transparency"],
              order = 2,
              type  = "range",
              min   = 0,
              max   = 1,
              step  = 0.01,
              bigStep = 0.05,
              isPercent = true,
              set   = "SetProp",
              get   = "GetAlpha",
              disabled = "GetAlphaDisabled",
              hidden = "GetAlphaDisabled",
            },
          },
        },
      },
      plugins = { }
    },
    rules = {
      name   = L["Rule"],
      order  = 3,
      type   = "group",
      args   = {
        mode = {
          name   = L["Select this state"],
          order  = 2,
          type   = "select",
          style  = "radio",
          values = { 
            default = L["by default"], 
            any = L["when ANY of these"], 
            all = L["when ALL of these"], 
            custom = L["via custom rule"],
            keybind = L["via keybinding"],
          },
          set    = "SetType",
          get    = "GetType",
        },
        clear = {
          name     = L["Clear All"],
          order    = 3,
          type     = "execute",
          hidden   = "GetClearAllDisabled",
          disabled = "GetClearAllDisabled",
          func     = "ClearAllConditions",
        },
        inputs = {
          name     = L["Conditions"],
          order    = 4,
          type     = "multiselect",
          hidden   = "GetConditionsDisabled",
          disabled = "GetConditionsDisabled",
          values   = ruleSelect,
          set      = "SetCondition",
          get      = "GetCondition",
        },
        custom = {
          name = L["Custom Rule"],
          order = 5,
          type = "input",
          multiline = true,
          hidden = "GetCustomDisabled",
          disabled = "GetCustomDisabled",
          desc = L["Syntax like macro rules: see preset rules for examples"],
          set  = "SetCustomRule",
          get  = "GetCustomRule",
          validate = "ValidateCustomRule",
        },
        keybind = {
          name = L["Keybinding"],
          order = 6,
          inline = true,
          hidden = "GetKeybindDisabled",
          disabled = "GetKeybindDisabled",
          type = "group",
          args = {
            desc = {
              name = L["Invoking a state keybind toggles an override of all other transition rules."],
              order = 1,
              type = "description",
            },
            keybind = {
              name = L["State Hotkey"],
              desc = L["Define an override toggle keybind"],
              order = 2,
              type = "keybinding",
              set  = "SetKeybind",
              get  = "GetKeybind",
            },
          },
        },
      },
    },
  }

  local handlers = { }
  local meta = {
    __index = function(self, key)
      for _, h in pairs(handlers) do
        if h[key] then
          return h[key]
        end
      end
    end,
  }
  local StateHandler = setmetatable({ }, meta)
  local proto        = { __index = StateHandler }

  function RegisterPropertyOptions( field, options, handler )
    stateOptions.properties.plugins[field] = options
    handlers[field] = handler
  end

  function UnregisterPropertyOptions( field )
    stateOptions.properties.plugins[field] = nil
    handlers[field] = nil
  end

  function StateHandler:New( bar, opts )
    local self = setmetatable(
      { 
        bar = bar 
      }, 
      proto )

    function self:GetName()
      return opts.name
    end

    function self:SetName(name)
      opts.name = name
    end

    function self:GetOrder()
      return opts.order
    end

    -- get reference to states table: even if the bar
    -- name changes the states table ref won't
    self.states = tbuild(module.db.profile.bars, bar:GetName(), "states")
    self.state  = tbuild(self.states, opts.name)

    opts.order = self:GetRuleField("order")
    if opts.order == nil then
      -- add after the highest
      opts.order = 100
      for _, state in pairs(self.states) do
        local x = tonumber(tfetch(state, "rule", "order"))
        if x and x >= opts.order then
          opts.order = x + 1
        end
      end
      self:SetRuleField("order",opts.order)
    end

    return self
  end

  -- helper methods

  function StateHandler:SetRuleField( key, value, ... )
    tbuild(self.state, "rule", ...)[key] = value
  end

  function StateHandler:GetRuleField( ... )
    return tfetch(self.state, "rule", ...)
  end

  function StateHandler:FixAll( setkey )
    -- if multiple selections in the same group are chosen when 'all' is selected,
    -- keep only one of them. If changing the mode, the first in the fields list will 
    -- be chosen arbitrarily. Otherwise, if selecting a new checkbox from the field-set,
    -- it will be retained.
    local notified = false
    if self:GetRuleField("type") == "all" then
      for _, c in ipairs(rules) do
        local rule, fields = unpack(c)
        local once = false
        if setkey then
          for idx, field in ipairs(fields) do
            if next(field) == setkey then
              once = true
            end
          end
        end
        for idx, field in ipairs(fields) do
          local key = next(field)
          if self:GetRuleField("values",key) then
            if once and key ~= setkey then
              self:SetRuleField(key,false,"values")
              if not setkey and not notified then
                ReAction:UserError(L["Warning: one or more incompatible rules were turned off"])
                notified = true
              end
            end
            once = true
          end
        end
      end
    end
  end

  function StateHandler:GetNeighbors()
    local before, after
    for k, v in pairs(self.states) do
      local o = tonumber(tfetch(v, "rule", "order"))
      if o and k ~= self:GetName() then
        local obefore = tfetch(self.states,before,"rule","order")
        local oafter  = tfetch(self.states,after,"rule","order")
        if o < self:GetOrder() and (not obefore or obefore < o) then
          before = k
        end
        if o > self:GetOrder() and (not oafter or oafter > o) then
          after = k
        end
      end
    end
    return before, after
  end

  function StateHandler:SwapOrder( a, b )
    -- do options table
    local args = optionMap[self.bar].args
    args[a].order, args[b].order = args[b].order, args[a].order
    -- do profile
    a = tbuild(self.states, a, "rule")
    b = tbuild(self.states, b, "rule")
    a.order, b.order = b.order, a.order
  end

  -- handler methods 

  function StateHandler:GetProp( info )
    -- gets property of the same name as the options arg
    return GetProperty(self.bar, self:GetName(), info[#info])
  end

  function StateHandler:SetProp( info, value )
    -- sets property of the same name as the options arg
    SetProperty(self.bar, self:GetName(), info[#info], value)
  end

  function StateHandler:DeleteState()
    if self.states[self:GetName()] then
      self.states[self:GetName()] = nil
      ApplyStates(self.bar)
    end
    optionMap[self.bar].args[self:GetName()] = nil
  end

  function StateHandler:SetStateName(info, value)
    -- check for existing state name
    if self.states[value] then
      ReAction:UserError(format(L["State named '%s' already exists"],value))
      return
    end
    local args = optionMap[self.bar].args
    local name = self:GetName()
    self.states[value], args[value], self.states[name], args[name] = self.states[name], args[name], nil, nil
    self:SetName(value)
    ApplyStates(self.bar)
    ReAction:ShowEditor(self.bar, moduleID, value)
    end

  function StateHandler:MoveStateUp()
    local before, after = self:GetNeighbors()
    if before then
      self:SwapOrder(before, self:GetName())
      ApplyStates(self.bar)
    end
  end

  function StateHandler:MoveStateDown()
    local before, after = self:GetNeighbors()
    if after then
      self:SwapOrder(self:GetName(), after)
      ApplyStates(self.bar)
    end
  end

  function StateHandler:GetAnchorDisabled()
    return not GetProperty(self.bar, self:GetName(), "anchorEnable")
  end

  function StateHandler:GetAnchorFrames(info)
    self._anchorframes = self._anchorframes or { }
    table.wipe(self._anchorframes)

    table.insert(self._anchorframes, "UIParent")
    for name, bar in ReAction:IterateBars() do
      table.insert(self._anchorframes, bar:GetFrame():GetName())
    end
    return self._anchorframes
  end

  function StateHandler:GetAnchorFrame(info)
    local value = self:GetProp(info)
    for k,v in pairs(self._anchorframes) do
      if v == value then
        return k
      end
    end
  end

  function StateHandler:SetAnchorFrame(info, value)
    local f = _G[self._anchorframes[value]]
    if f then
      self.bar:SetFrameRef("anchor-"..self:GetName(), f)
      self:SetProp(info, f:GetName())
    end
  end

  function StateHandler:SetAnchorPointProp(info, value)
    self:SetProp(info, value ~= "NONE" and value or nil)
  end

  function StateHandler:GetAnchorPointProp(info)
    return self:GetProp(info) or "NONE"
  end

  function StateHandler:GetScale(info)
    return self:GetProp(info) or 1.0
  end

  function StateHandler:GetScaleDisabled()
    return not GetProperty(self.bar, self:GetName(), "enableScale")
  end

  function StateHandler:GetAlpha(info)
    return self:GetProp(info) or 1.0
  end

  function StateHandler:GetAlphaDisabled()
    return not GetProperty(self.bar, self:GetName(), "enableAlpha")
  end

  function StateHandler:SetType(info, value)
    self:SetRuleField("type", value)
    self:FixAll()
    ApplyStates(self.bar)
  end

  function StateHandler:GetType()
    return self:GetRuleField("type")
  end

  function StateHandler:GetClearAllDisabled()
    local t = self:GetRuleField("type")
    return not( t == "any" or t == "all" or t == "custom")
  end

  function StateHandler:ClearAllConditions()
    local t = self:GetRuleField("type")
    if t == "custom" then
      self:SetRuleField("custom","")
    elseif t == "any" or t == "all" then
      self:SetRuleField("values", {})
    end
    ApplyStates(self.bar)
  end

  function StateHandler:GetConditionsDisabled()
    local t = self:GetRuleField("type")
    return not( t == "any" or t == "all")
  end

  function StateHandler:SetCondition(info, key, value)
    self:SetRuleField(ruleMap[key], value or nil, "values")
    if value then
      self:FixAll(ruleMap[key])
    end
    ApplyStates(self.bar)
  end

  function StateHandler:GetCondition(info, key)
    return self:GetRuleField("values", ruleMap[key]) or false
  end

  function StateHandler:GetCustomDisabled()
    return self:GetRuleField("type") ~= "custom"
  end

  function StateHandler:SetCustomRule(info, value)
    self:SetRuleField("custom",value)
    ApplyStates(self.bar)
  end

  function StateHandler:GetCustomRule()
    return self:GetRuleField("custom") or ""
  end

  function StateHandler:ValidateCustomRule(info, value)
    local s = value:gsub("%s","") -- remove all spaces
    -- unfortunately %b and captures don't support the '+' notation, or this would be considerably simpler
    repeat
      if s == "" then
        return true
      end
      local c, r = s:match("(%b[])(.*)")
      if c == nil and s and #s > 0 then
        return format(L["Invalid custom rule '%s': each clause must appear within [brackets]"],value or "")
      end
      s = r
    until c == nil
    return true
  end

  function StateHandler:GetKeybindDisabled()
    return self:GetRuleField("type") ~= "keybind"
  end

  function StateHandler:GetKeybind()
    return self:GetRuleField("keybind")
  end

  function StateHandler:SetKeybind(info, value)
    if value and #value == 0 then
      value = nil
    end
    self:SetRuleField("keybind",value)
    ApplyStates(self.bar)
  end

  local function CreateStateOptions(bar, name)
    local opts = { 
      type = "group",
      name = name,
      childGroups = "tab",
      args = stateOptions
    }

    opts.handler = StateHandler:New(bar,opts)

    return opts
  end

  function module:GetBarOptions(bar)
    local private = { }
    local states = tbuild(module.db.profile.bars, bar:GetName(), "states")
    local options = {
      name = L["Dynamic State"],
      type = "group",
      order = -1,
      childGroups = "tree",
      disabled = InCombatLockdown,
      args = {
        __desc__ = {
          name = L["States are evaluated in the order they are listed"],
          order = 1,
          type = "description",
        },
        __new__ = {
          name = L["New State..."],
          order = 2,
          type = "group",
          args = {
            name = {
              name = L["State Name"],
              desc = L["Set a name for the new state"],
              order = 1,
              type = "input",
              get = function() return private.newstatename or "" end,
              set = function(info,value) private.newstatename = value end,
              pattern = "^%w*$",
              usage = L["State names must be alphanumeric without spaces"],
            },
            create = {
              name = L["Create State"],
              order = 2,
              type = "execute",
              func = function ()
                  local name = private.newstatename
                  if states[name] then
                    ReAction:UserError(format(L["State named '%s' already exists"],name))
                  else
                    -- TODO: select default state options and pass as final argument
                    states[name] = { }
                    optionMap[bar].args[name] = CreateStateOptions(bar,name)
                    ReAction:ShowEditor(bar, moduleID, name)
                    private.newstatename = ""
                  end
                end,
              disabled = function()
                  local name = private.newstatename or ""
                  return #name == 0 or name:find("%W")
                end,
            }
          }
        }
      }
    }
    for name, config in pairs(states) do
      options.args[name] = CreateStateOptions(bar,name)
    end
    optionMap[bar] = options
    return options
  end
end

-- Module API --

-- Pass in a property field-name, an implementation secure snippet, a static options table, and an 
-- optional options handler method-table
--
-- The options table is static, i.e. not bar-specific and should only reference handler method
-- strings (either existing ones or those added via optHandler). The existing options are ordered
-- 90-99. Order #1 is reserved for the heading.
--
-- The contents of optHandler, if provided, will be added to the existing StateHandler options metatable.
-- See above, for existing API. In particular see the properties set up in the New method: self.bar,
-- self.states, and self:GetName(), and the generic property handlers self:GetProp() and self:SetProp().
--
function module:RegisterStateProperty( field, snippetHandler, options, optHandler )
  RegisterProperty(field, snippetHandler)
  RegisterPropertyOptions(field, options, optHandler)
end

function module:UnregisterStateProperty( field )
  UnregisterProperty(field)
  UnregisterPropertyOptions(field)
end


-- Export methods to Bar class --

ReAction.Bar.GetStateProperty = GetProperty
ReAction.Bar.SetStateProperty = SetProperty