-- CastBar.lua
local _;
local unpack = unpack;
local ssub = string.sub;
local min = math.min;
local ceil = math.ceil;
local UnitCastingInfo, UnitChannelInfo = UnitCastingInfo, UnitChannelInfo;
local GetTime = GetTime;

local barTexture = "Interface\\AddOns\\OmaRF\\images\\minimalist";
local castingColor = {1, 0.49, 0}; -- from Quartz defaults
local nointerruptColor = {0.6, 0.6, 0.6};
local channelingColor = {0.32, 0.3, 1};

local M = {};
OmaUFCastBar = M;

-- TODO trade skill bar updates as well, check Quartz modules/Tradeskill.lua
local function onUpdate(bar)
    if not bar:IsShown() then return end
    local width = bar.icon:IsShown() and bar.cast.width or bar.cast.width; -- TODO fullwidth
    local startTime, endTime = bar.startTime, bar.endTime;
    local currentClamped = min(GetTime(), endTime);
    local remaining = endTime - currentClamped;
    local percent;
    if bar.channeling then
        percent = remaining / (endTime - startTime);
    else
        percent = (currentClamped - startTime) / (endTime - startTime);
    end

    width = percent*width;
    if width <= 0 then
        bar.cast:SetWidth(0.1);
    else
        bar.cast:SetWidth(width);
    end
    bar.time:SetFormattedText("%.1f", remaining);
end

local function showBar(bar)
    bar:Show();
    bar:SetScript("OnUpdate", onUpdate);
end

local function hideBar(bar)
    bar:Hide();
    bar:SetScript("OnUpdate", nil);
end

local function toggleInterruptible(bar, nointr)
    if bar.unit == "player" then return end
    if nointr then
        bar.cast:SetVertexColor(unpack(nointerruptColor));
        bar.shield:Show();
    else
        bar.cast:SetVertexColor(unpack(bar.cast.color));
        bar.shield:Hide();
    end
end

local function startCast(bar, unit, channeling)
    local name, icon, startTime, endTime, noInterrupt, id;
    if channeling then
        name, _, _, icon, startTime, endTime, _, noInterrupt = UnitChannelInfo(unit);
        if not startTime or not endTime then return nil end
        bar.channeling = true;
        bar.cast.color = channelingColor;
    else
        _, _, name, icon, startTime, endTime, _, _, noInterrupt, id = UnitCastingInfo(unit);
        if not startTime or not endTime then return nil end
        bar.channeling = nil;
        bar.cast.color = castingColor;
    end
    bar.startTime = startTime / 1000;
    bar.endTime = endTime / 1000;
    -- don't show samwise for non-existent icons
    if icon ~= "Interface\\Icons\\Temp" then
        bar.icon:SetTexture(icon);
        bar.icon:Show();
        bar.cast:SetWidth(channeling and bar.cast.width or 0.1);
    else
        bar.icon:Hide();
        bar.cast:SetWidth(channeling and bar.cast.width or 0.1); -- TODO use fullwidth
    end
    bar.spell:SetText(ssub(name, 1, bar.spell.count));
    bar.time:SetFormattedText("%.1f", (endTime - startTime)/1000);
    bar.cast:SetVertexColor(unpack(bar.cast.color));
    showBar(bar);
    toggleInterruptible(bar, noInterrupt);
    return true;
end

local function applyDelay(bar, unit, channeling)
    local startTime, endTime;
    if channeling then
        _, _, _, _, startTime, endTime = UnitChannelInfo(unit);
    else
        _, _, _, _, startTime, endTime = UnitCastingInfo(unit);
    end
    if not startTime or not endTime then return hideBar(bar) end
    bar.startTime = startTime / 1000;
    bar.endTime = endTime / 1000;
    -- TODO show delay text
end

local events = {
    ["UNIT_SPELLCAST_START"] = function(bar, unit)
        startCast(bar, unit);
    end,
    ["PLAYER_TARGET_CHANGED"] = function(bar)
        hideBar(bar);
        if not startCast(bar, bar.unit) then
            startCast(bar, bar.unit, true);
        end
    end,
    ["UNIT_SPELLCAST_CHANNEL_START"] = function(bar, unit)
        startCast(bar, unit, true);
    end,
    ["UNIT_SPELLCAST_STOP"] = function(bar)
        hideBar(bar);
    end,
    ["UNIT_SPELLCAST_DELAYED"] = function(bar, unit)
        applyDelay(bar, unit);
    end,
    ["UNIT_SPELLCAST_CHANNEL_UPDATE"] = function(bar, unit)
        applyDelay(bar, unit, true);
    end,
    ["UNIT_SPELLCAST_INTERRUPTIBLE"] = function(bar)
        toggleInterruptible(bar, false);
    end,
    ["UNIT_SPELLCAST_NOT_INTERRUPTIBLE"] = function(bar)
        toggleInterruptible(bar, true);
    end,
};
events["UNIT_SPELLCAST_CHANNEL_STOP"] = events["UNIT_SPELLCAST_STOP"];

local function onEvent(bar, event, unit)
    if unit == bar.unit or (bar.unit == "player" and unit == "vehicle") then
        events[event](bar, unit);
    elseif event == "PLAYER_TARGET_CHANGED" then
        events[event](bar);
    end
end

function M.RegisterCastEvents(bar)
    --bar:RegisterEvent("UNIT_SPELLCAST_SENT");
    bar:RegisterEvent("UNIT_SPELLCAST_START");
    bar:RegisterEvent("UNIT_SPELLCAST_STOP");
    --bar:RegisterEvent("UNIT_SPELLCAST_FAILED");
    --bar:RegisterEvent("UNIT_SPELLCAST_INTERRUPTED");
    bar:RegisterEvent("UNIT_SPELLCAST_DELAYED");
    bar:RegisterEvent("UNIT_SPELLCAST_CHANNEL_START");
    bar:RegisterEvent("UNIT_SPELLCAST_CHANNEL_STOP");
    bar:RegisterEvent("UNIT_SPELLCAST_CHANNEL_UPDATE");
    bar:RegisterEvent("UNIT_SPELLCAST_INTERRUPTIBLE");
    bar:RegisterEvent("UNIT_SPELLCAST_NOT_INTERRUPTIBLE");
    if bar.unit == "target" then bar:RegisterEvent("PLAYER_TARGET_CHANGED") end
    -- trigger initial check
    if not startCast(bar, bar.unit) then
        startCast(bar, bar.unit, true);
    end
end

function M.UnregisterCastEvents(bar)
    bar:UnregisterAllEvents();
    hideBar(bar);
end

function M.CreateCastBar(parent, unit, yoffset)
    local bar = CreateFrame("Frame", parent:GetName().."CastBar", parent);
    bar.unit = unit;
    bar:SetPoint("BOTTOMLEFT", parent, "TOPLEFT", 0, yoffset);
    bar:SetPoint("BOTTOMRIGHT", parent, "TOPRIGHT", 0, yoffset);
    bar:SetHeight(22);
    bar:Hide();
    bar.back = bar:CreateTexture(nil, "BACKGROUND");
    bar.back:SetAllPoints();
    bar.back:SetColorTexture(0, 0, 0, 0.7);
    bar.icon = bar:CreateTexture(nil, "ARTWORK", 1);
    bar.icon:SetPoint("TOPLEFT", bar, "TOPLEFT", 1, -1);
    bar.icon:SetPoint("BOTTOMRIGHT", bar, "BOTTOMLEFT", 21, 1);
    bar.icon:SetTexCoord(0.07, 0.93, 0.07, 0.93); -- remove borders (from Quartz)
    bar.shield = bar:CreateTexture(nil, "ARTWORK");
    bar.shield:SetPoint("CENTER", bar.icon, "CENTER", -2, -1);
    bar.shield:SetWidth(28);
    bar.shield:SetHeight(50);
    bar.shield:SetTexture("Interface\\CastingBar\\UI-CastingBar-Small-Shield");
    bar.shield:SetTexCoord(0, 36/256, 0, 1);
    bar.shield:Hide();
    bar.cast = bar:CreateTexture(nil, "ARTWORK");
    bar.cast:SetPoint("TOPLEFT", bar.icon, "TOPRIGHT", 1, 0);
    bar.cast:SetPoint("BOTTOMLEFT", bar.icon, "BOTTOMRIGHT", 1, 0);
    bar.cast.width = bar:GetWidth() - bar.icon:GetWidth() - 3;
    bar.cast.fullwidth = bar:GetWidth() - 2; -- for casts without icon
    bar.cast:SetWidth(bar.cast.width);
    bar.cast:SetTexture(barTexture);
    bar.cast.color = castingColor;
    bar.spell = bar:CreateFontString(nil, "OVERLAY", "GameFontHighlight");
    bar.spell:SetPoint("LEFT", bar.icon, "RIGHT", 2, 0);
    bar.spell.count = ceil(bar.cast:GetWidth()/10);
    bar.time = bar:CreateFontString(nil, "OVERLAY", "GameFontHighlight");
    bar.time:SetPoint("RIGHT", bar, "RIGHT", -2, 0);
    bar:SetScript("OnEvent", onEvent);
    return bar;
end