local addonName, addon = ...
local L = addon.L

--local astrolabe = DongleStub("Astrolabe-1.0")
local mapdata = LibStub("LibMapData-1.0")

local PI2 = math.pi * 2

-- This file is an API abstraction over the mapping system in World of
-- Warcraft, however it does not aim to be a complete abstraction. Instead, we
-- merely provide those functions that are relevant to TomTom, and try to
-- provide a way for the necessary data to be obtained without care for how it
-- is obtained.

local function getDirection(xd, yd)
    if not xd or not yd then
        return nil
    end

    local angle = math.atan2(xd, -yd)
    if angle > 0 then
        angle = PI2 - angle
    else
        angle = -angle
    end

    return angle
end

-- Calculates the distance (in yards) and angle (in radians) between two points
-- on the map. This may be two points within the same map file, or two points
-- on different maps. In the case that the points are on different maps and
-- there's no 'distance' that quite makes sense, this function will simply
-- return nil

function addon:GetVector(sm, sf, sx, sy, dm, df, dx, dy)
    if smap == dmap and sfloor == dfloor then
        -- The waypoints are on the same map, so calculate directly using map data

        if mapdata then
            local dist, xd, yd = mapdata:Distance(sm, sf, sx, sy, dx, dy)
            local angle = getDirection(xd, yd)

            if dist and angle then
                return dist, angle
            end
        elseif astrolabe then
            local dist, xd, yd = astrolabe:ComputeDistance(sm, sf, sx, sy, dm, df, dx, dy)
            local angle = GetDirection(xd, yd)
            if dist and angle then
                return dist, angle
            end
        else
            error("No map data available for 'GetVector'")
        end
    else
        -- The waypoints are on different maps

        if mapdata then
            local dist, xd, yd = mapdata:DistanceWithinContinent(sm, sf, sx, sy, dm, df, dx, dy)
            local angle = GetDirection(xd, yd)
            if dist and angle then
                return dist, angle
            end
        elseif astrolabe then
            local dist, xd, yd = astrolabe:ComputeDistance(sm, sf, sx, sy, dm, df, dx, dy)
            local angle = GetDistance(xd, yd)
            if dist and angle then
                return dist, angle
            end
        else
            error("No map data available for 'GetVector'")
        end
    end
end

-- Get the distance (in yards) and angle (in radians) from the player's current
-- position to a position on the map.

function addon:GetVectorFromCurrent(map, floor, x, y)

    -- First we need to obtain the player's current position. Attempt, at all
    -- costs to do this without changing the map zoom, as it shouldn't be
    -- necessary.

    local cmap, cfloor = GetCurrentMapAreaID()
    local cx, cy = GetPlayerMapPosition("player")

    if map and floor and x and y then
        return self:GetVector(cmap, cfloor, cx, cy, map, floor, x, y)
    end
end

-- This function returns the display name for a given map. If the name is not
-- available, then "Unknown map: %d" is displayed
function addon:GetMapDisplayName(map)
    if mapdata then
        local name = mapdata:MapLocalize(map)
        return name or string.format("Unknown map: %d", map)
    elseif astrolabe then
        return string.format("Unknown map: %d", map)
    end
end

-- This data is hardcoded, and should be able to be automatically obtained
local continents = {
    -- Map for cosmic (both ways)
    [WORLDMAP_COSMIC_ID] = -1,   -- Cosmic map (-1)

    -- Map from mapId to continentIndex
    [13] = 1,                    -- Kalimdor (1)
    [14] = 2,                    -- Eastern Kingdoms (2)
    [466] = 3,                   -- Outland (3)
    [485] = 4,                   -- Northrend (4)
    [751] = 5,                   -- Maelstrom (5)

    -- Map from continentIndex to mapId
    [1] = 13,
    [2] = 14,
    [3] = 466,
    [4] = 485,
    [5] = 751,
}

-- Returns if a given map file is a continent map
function addon:IsContinentMap(map)
    return not not continents[map]
end

-- Returns the continent map that 'owns' a given map. This does NOT return the
-- continent index, but rather the continent map file.
function addon:GetMapContinentMap(map)
    if mapdata then
        local cindex = mapdata:GetContinentFromMap(map)
        local cmap = continents[cindex]
        return cmap
    elseif astrolabe then
    end
end