-- A Gen 2 export that moved maps carries the new map's object window
-- (data/maps/setup_scripts.asm MapSetupScript_Continue, home/map.asm
-- ReadObjectEvents). Same-map exports leave the template's window alone,
-- byte for byte, which is the #1852 guarantee these tests also pin.
package.path = "./?.lua;./?/init.lua;" .. package.path

local T = require("tests.modkit")
local Gen2Save = require("src.save_convert.Gen2Save")
local Gen2Layout = require("src.save_convert.Gen2Layout")
local Gen2MapContext = require("src.save_convert.Gen2MapContext")

local SIZE = Gen2Save.SAVE_SIZE
local MAPOBJECT = Gen2MapContext.MAPOBJECT_LENGTH
local STRUCT = Gen2MapContext.OBJECT_LENGTH

-- A sealed template standing on a chosen map, with a recognizable pattern
-- across its whole object window so both preservation and rebuild are
-- visible in the bytes. Synthesized, not checked in: a real .sav is
-- personal data, same rule tests/engine/gen2_save_import.lua follows.
local function template(L, O, group, number)
  local b = {}
  for i = 0, SIZE - 1 do b[i] = 0 end
  b[L.wMapGroup], b[L.wMapNumber] = group, number
  for i = 0, Gen2MapContext.NUM_OBJECTS * MAPOBJECT - 1 do
    b[O.mapObjects + i] = 0xA0 + i % 16
  end
  for i = 0, Gen2MapContext.NUM_OBJECT_STRUCTS * STRUCT - 1 do
    b[O.objectStructs + i] = 0xB0 + i % 16
  end
  for i = 0, Gen2MapContext.NUM_OBJECTS - 1 do b[O.objectMasks + i] = 0xC0 end
  b[O.objectFollow], b[O.objectFollow + 1] = 3, 4
  b[O.objectEventCount] = 9
  b[L.sCheckValue1] = 0x63
  b[L.sCheckValue2] = 0x7F
  local sum = 0
  for i = L.sGameData, L.sGameDataEnd - 1 do sum = (sum + b[i]) % 65536 end
  b[L.sChecksum] = sum % 256
  b[L.sChecksum + 1] = math.floor(sum / 256) % 256
  local out = {}
  for i = 0, SIZE - 1 do out[i + 1] = string.char(b[i]) end
  return table.concat(out)
end

-- The map the moved save lands on: two objects, one carrying every field a
-- real object_event can, one minimal.
local function fixtureData(group, number)
  return {
    pokemon = {}, moves = {}, items = {},
    maps = {
      FIX_HOUSE = {
        group = group, map = number,
        objectEventsAddr = 0x5A17,
        objects = {
          {
            index = 1, spriteId = 0x2F, x = 3, y = 5, movement = 0x07,
            radius = { y = 2, x = 1 }, hours = { -1, 20 },
            palette = 4, type = 2, sight = 0,
            script = 0x6BCD, eventFlag = 0x02A5,
          },
          {
            index = 2, spriteId = 0x11, x = 0, y = 0, movement = 0x01,
            radius = { y = 0, x = 0 }, hours = { -1, -1 },
            palette = 0, type = 5, sight = 3,
            script = 0x6BE0,
          },
        },
      },
    },
  }
end

local function save(group, number, x, y)
  return {
    player = { name = "TESTER" },
    position = { mapGroup = group, mapNumber = number, x = x, y = y },
  }
end

local function u8(bytes, at) return bytes:byte(at + 1) end

for _, spec in ipairs({
  { version = "crystal", L = Gen2Layout.crystal, O = Gen2MapContext.OFFSETS.crystal },
  { version = "gold", L = Gen2Layout.goldSilver, O = Gen2MapContext.OFFSETS.goldSilver },
}) do
  local L, O = spec.L, spec.O
  local tpl = template(L, O, 21, 14)

  -- Same map: the template's whole object window survives untouched.
  local bytes, err = Gen2Save.encode(save(21, 14, 6, 1), spec.version, tpl,
    fixtureData(21, 14))
  T.check(bytes, spec.version .. " same-map export succeeds: " .. tostring(err))
  local windowSame = true
  for i = 0, Gen2MapContext.NUM_OBJECTS * MAPOBJECT - 1 do
    if u8(bytes, O.mapObjects + i) ~= u8(tpl, O.mapObjects + i) then
      windowSame = false
      break
    end
  end
  T.check(windowSame, spec.version .. ": same-map export leaves wMapObjects byte-identical")
  T.eq(u8(bytes, O.objectEventCount), 9,
    spec.version .. ": same-map export leaves the object count alone")

  -- Moved: the window is the NEW map's, exactly as ReadObjectEvents lays
  -- it out.
  bytes, err = Gen2Save.encode(save(21, 15, 6, 1), spec.version, tpl,
    fixtureData(21, 15))
  T.check(bytes, spec.version .. " moved export succeeds: " .. tostring(err))

  local slot1 = O.mapObjects + MAPOBJECT
  local expected = {
    0xFF, 0x2F, 5 + 4, 3 + 4, 0x07,
    2 * 16 + 1, 0xFF, 20, 4 * 16 + 2, 0x00,
    0xCD, 0x6B, 0xA5, 0x02, 0, 0,
  }
  for i, want in ipairs(expected) do
    T.eq(u8(bytes, slot1 + i - 1), want,
      ("%s: object 1 byte %d"):format(spec.version, i))
  end
  T.eq(u8(bytes, slot1 + MAPOBJECT + 1), 0x11, spec.version .. ": object 2 sprite")
  -- An object with no event flag writes the -1 the game uses for "none".
  T.eq(u8(bytes, slot1 + MAPOBJECT + 12), 0xFF, spec.version .. ": no-flag object writes $FFFF")
  T.eq(u8(bytes, slot1 + MAPOBJECT + 13), 0xFF, spec.version .. ": no-flag object writes $FFFF hi")
  -- The first empty slot carries ReadObjectEvents' 0 / -1 pattern.
  local empty = slot1 + 2 * MAPOBJECT
  T.eq(u8(bytes, empty), 0, spec.version .. ": empty slot struct id")
  T.eq(u8(bytes, empty + 1), 0xFF, spec.version .. ": empty slot sprite")

  -- The player: map object coordinates re-anchored, sprite untouched.
  T.eq(u8(bytes, O.mapObjects + 2), 1 + 4, spec.version .. ": player map object y")
  T.eq(u8(bytes, O.mapObjects + 3), 6 + 4, spec.version .. ": player map object x")
  T.eq(u8(bytes, O.mapObjects + 1), u8(tpl, O.mapObjects + 1),
    spec.version .. ": player map object sprite keeps the template's byte")

  -- The player struct moves with them; the NPC structs are cleared.
  T.eq(u8(bytes, O.objectStructs + Gen2MapContext.STRUCT_MAP_X), 6 + 4,
    spec.version .. ": player struct map x")
  T.eq(u8(bytes, O.objectStructs + Gen2MapContext.STRUCT_MAP_Y), 1 + 4,
    spec.version .. ": player struct map y")
  T.eq(u8(bytes, O.objectStructs + STRUCT), 0, spec.version .. ": NPC struct 1 cleared")
  T.eq(u8(bytes, O.objectStructs + 12 * STRUCT + STRUCT - 1), 0,
    spec.version .. ": NPC struct 12 cleared to its last byte")

  -- Masks, follow, count and pointer.
  T.eq(u8(bytes, O.objectMasks), 0, spec.version .. ": object masks cleared")
  T.eq(u8(bytes, O.objectMasks + 15), 0, spec.version .. ": all sixteen of them")
  T.eq(u8(bytes, O.objectFollow), 0xFF, spec.version .. ": follow leader reset")
  T.eq(u8(bytes, O.objectFollow + 1), 0xFF, spec.version .. ": follow follower reset")
  T.eq(u8(bytes, O.objectEventCount), 2, spec.version .. ": object count")
  T.eq(u8(bytes, O.objectEventsPointer), 0x17, spec.version .. ": events pointer lo")
  T.eq(u8(bytes, O.objectEventsPointer + 1), 0x5A, spec.version .. ": events pointer hi")

  -- And the checksum still seals the block the game verifies.
  T.check(Gen2Save.checksumValid(bytes, L), spec.version .. ": moved export checksums")

  -- Refusals: an unknown map, and a cache from before the extractor kept
  -- the object-table address.
  local refused, why = Gen2Save.encode(save(9, 9, 0, 0), spec.version, tpl,
    fixtureData(21, 15))
  T.check(refused == nil and why:find("unknown map 9/9", 1, true),
    spec.version .. ": unknown map refuses: " .. tostring(why))

  local stale = fixtureData(21, 15)
  stale.maps.FIX_HOUSE.objectEventsAddr = nil
  refused, why = Gen2Save.encode(save(21, 15, 0, 0), spec.version, tpl, stale)
  T.check(refused == nil and why:find("re%-import the ROM"),
    spec.version .. ": stale cache refuses with the re-import hint: " .. tostring(why))
end

T.finish("gen2 save export map objects")