-- Minimal Tiled (TMX) map loader for simple orthogonal maps with CSV layers.
local TMX = {}

local function attr(tag, name)
  local v = tag:match(name .. '="([^"]*)"')
  return v and tonumber(v) or nil
end

function TMX.load(path)
  local text = love.filesystem.read(path)

  local header = text:match('<map%s-[^>]*>')
  if not header then
    error('TMX.load: no <map> tag in ' .. path)
  end

  local map = {
    width = attr(header, 'width'),
    height = attr(header, 'height'),
    tileWidth = attr(header, 'tilewidth') or 16,
    tileHeight = attr(header, 'tileheight') or 16,
  }

  local imgSrc = text:match('<image%s-[^>]*source="([^"]+)"')
  if not imgSrc then
    error('TMX.load: no <image> tag in ' .. path)
  end
  map.imagePath = imgSrc

  local csv = text:match('<data encoding="csv">(.-)</data>')
  if not csv then
    error('TMX.load: no CSV layer data in ' .. path)
  end

  local tiles = {}
  for gid in csv:gmatch('%d+') do
    tiles[#tiles + 1] = tonumber(gid)
  end
  map.tiles = tiles

  local expected = map.width * map.height
  if #tiles ~= expected then
    error(('TMX.load: %s has %d tiles, expected %d'):format(path, #tiles, expected))
  end

  return map
end

function TMX.isSolid(map, tx, ty)
  if tx < 0 or ty < 0 or tx >= map.width or ty >= map.height then
    return true -- out of bounds counts as solid so the player can't leave
  end
  return (map.tiles[ty * map.width + tx + 1] or 0) > 0 -- tiles are 1-indexed
end

return TMX