-- Importing a Gen 2 cart save (Gold, Silver, Crystal).
--   luajit tests/gen2_save_import_test.lua
-- Also dofile'd by tests/run_tests.lua.
--
-- The save this builds is synthesized rather than checked in, the same rule
-- tests/save_convert_tests.lua follows for Gen 1: a real .sav is personal
-- data. Point POKEPORT_GEN2_SAV_FIXTURE at one to run the audit at the
-- bottom against your own Gold/Silver/Crystal save.
--
-- Every offset under test comes from src/save_convert/Gen2Layout.lua, which
-- tools/gen2_sram_offsets.py generates from a pret build. The reason that
-- matters is here in miniature: Gold and Crystal disagree on almost every
-- field, so reading one with the other's table is not a near miss, it is a
-- party count of 133.
package.path = "./?.lua;./?/init.lua;" .. package.path

love = love or require("tests.love_stub")

local T = require("tests.harness")
local check, eq = T.check, T.eq

local Gen2Save = require("src.save_convert.Gen2Save")
local Gen2Layout = require("src.save_convert.Gen2Layout")
local SaveConvert = require("src.save_convert.SaveConvert")

local SIZE = Gen2Save.SAVE_SIZE

-- A byte-addressable save under construction.
local function blank()
  local b = {}
  for i = 0, SIZE - 1 do b[i] = 0 end
  return b
end
local function put(b, at, ...)
  local vals = { ... }
  for i, v in ipairs(vals) do b[at + i - 1] = v % 256 end
end
local function putName(b, at, name)
  for i = 1, #name do b[at + i - 1] = 0x80 + (name:byte(i) - 65) end
  b[at + #name] = 0x50
end
local function sealOne(b, L)
  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
end

-- A real cart seals both copies, and the game rewrites the backup from the
-- primary on every successful load.
local function seal(b, L)
  if L.backup then
    for i = 0, (L.sGameDataEnd - L.sGameData) - 1 do
      b[L.backup.sGameData + i] = b[L.sGameData + i]
    end
    sealOne(b, L.backup)
  end
  sealOne(b, L)
end
local function pack(b)
  local out = {}
  for i = 0, SIZE - 1 do out[i + 1] = string.char(b[i]) end
  return table.concat(out)
end

-- A save with one known Pokemon in the party and one in box 3.
local function build(version)
  local L = Gen2Save.layoutFor(version)
  local b = blank()
  putName(b, L.wPlayerName, "ASH")
  putName(b, L.wRivalName, "GARY")
  putName(b, L.wMomsName, "MOM")
  put(b, L.wPlayerID, 0x12, 0x34)          -- big-endian 0x1234
  put(b, L.wMoney, 0x01, 0xE2, 0x40)       -- 123456
  put(b, L.wBadges, 0x05)                  -- ZEPHYR + PLAIN
  put(b, L.wPartyCount, 1)
  put(b, L.wPartySpecies, 155)
  local mon = L.wPartyMons
  put(b, mon, 155)                         -- species
  put(b, mon + 1, 0)                       -- no held item
  put(b, mon + 2, 33, 43, 0, 0)            -- two moves
  put(b, mon + 6, 0x12, 0x34)              -- OT id
  put(b, mon + 0x15, 0x9F, 0x6A)           -- DVs: a=9 d=15 s=6 sp=10
  put(b, mon + 0x1B, 200)                  -- happiness
  put(b, mon + 0x1F, 42)                   -- level
  put(b, mon + 0x20, 0x10)                 -- BRN (bit 4)
  put(b, mon + 0x22, 0x00, 0x64)           -- hp 100
  put(b, mon + 0x24, 0x00, 0x64)           -- maxHp 100
  put(b, mon + 0x26, 0x00, 0x37)           -- attack 55
  putName(b, L.wPartyMonNicknames, "FLAME")
  putName(b, L.wPartyMonOTs, "ASH")
  put(b, L.wMapGroup, 21); put(b, L.wMapNumber, 14)
  put(b, L.wNumItems, 1); put(b, L.wItems, 20, 3); put(b, L.wItems + 2, 0xFF)
  put(b, L.wNumKeyItems, 1); put(b, L.wKeyItems, 7); put(b, L.wKeyItems + 1, 0xFF)
  put(b, L.wNumBalls, 1); put(b, L.wBalls, 5, 9); put(b, L.wBalls + 2, 0xFF)
  -- box 3, one Pokemon
  local box = L.boxes[3]
  put(b, box, 1)
  put(b, box + 0x01, 7)
  put(b, box + 0x16, 7)
  put(b, box + 0x16 + 0x1F, 15)
  putName(b, box + 0x296, "ASH")
  putName(b, box + 0x372, "SQUIRT")
  seal(b, L)
  return pack(b)
end

-- ------------------------------------------------------------------
-- What the cart holds comes back out
-- ------------------------------------------------------------------

for _, version in ipairs({ "gold", "silver", "crystal" }) do
  local save, err = Gen2Save.decode(build(version), version)
  check(save ~= nil, version .. ": a valid save decodes -- " .. tostring(err))
  if save then
    eq(save.player.name, "ASH", version .. ": player name")
    eq(save.rival.name, "GARY", version .. ": rival name")
    eq(save.player.id, 0x1234, version .. ": trainer id is big-endian")
    eq(save.player.money, 123456, version .. ": money is a 3-byte big-endian")
    eq(save.player.badges.ZEPHYR, true, version .. ": badges are keyed by name")
    eq(save.player.badges.PLAIN, true, version .. ": and the second bit too")
    eq(save.player.badges.HIVE, nil, version .. ": an unearned badge is absent")
    eq(#save.party, 1, version .. ": party size")
    local m = save.party[1]
    eq(m.species, 155, version .. ": species, uncrosswalked")
    eq(m.level, 42, version .. ": level")
    eq(m.maxHp, 100, version .. ": max hp")
    eq(m.stats.attack, 55, version .. ": computed stats come off the party tail")
    eq(#m.moves, 2, version .. ": empty move slots are dropped")
    eq(m.nickname, "FLAME", version .. ": nickname")
    eq(m.ot, "ASH", version .. ": OT name")
    eq(m.happiness, 200, version .. ": happiness")
    -- DVs are nibbles, and the HP DV is rebuilt from the other four's low bits
    eq(m.dvs.attack, 9, version .. ": attack DV is the high nibble")
    eq(m.dvs.defense, 15, version .. ": defense DV is the low nibble")
    eq(m.dvs.speed, 6, version .. ": speed DV")
    eq(m.dvs.special, 10, version .. ": special DV")
    eq(m.dvs.hp, 12, version .. ": HP DV is rebuilt, not stored")
    eq(#save.boxes, 14, version .. ": every box is present")
    eq(#save.boxes[3], 1, version .. ": box 3 holds one Pokemon")
    eq(save.boxes[3][1].species, 7, version .. ": the stored species, uncrosswalked")
    eq(save.boxes[3][1].nickname, "SQUIRT", version .. ": box nicknames follow the OTs")
    eq(save.boxes[3][1].ot, "ASH", version .. ": box OT")
    eq(save.boxes[3][1].hp, nil, version .. ": a box mon carries no computed stats")
  end
end

-- ------------------------------------------------------------------
-- The engine is keyed by name, so the codec has to translate
-- ------------------------------------------------------------------
--
-- The cart stores numbers. save.inventory holds POTION, mon.species is
-- "TYPHLOSION", data.pokemon is indexed by that name. Without this the import
-- looks perfect and the engine cannot read a byte of it.

local CROSSWALK = {
  pokemon = { CYNDAQUIL = { index = 155 }, SQUIRTLE = { index = 7 } },
  moves   = { TACKLE = { index = 33 }, LEER = { index = 43 } },
  items   = { POTION = { index = 20 }, BICYCLE = { index = 7 },
              POKE_BALL = { index = 5 } },
  maps    = { GOLDENROD_CITY = { group = 21, map = 14 } },
}

do
  local save = assert(Gen2Save.decode(build("gold"), "gold", CROSSWALK))
  local m = save.party[1]
  eq(m.species, "CYNDAQUIL", "species is the engine's id, not the cart's number")
  eq(m.moves[1], "TACKLE", "and so are moves")
  eq(m.moves[2], "LEER", "both of them")
  eq(save.boxes[3][1].species, "SQUIRTLE", "boxes translate too")

  -- One flat bag. Nothing in src reads save.keyItems or save.balls; PackMenu
  -- buckets save.inventory by each item's own pocket.
  eq(save.keyItems, nil, "there is no separate key item table")
  eq(save.balls, nil, "nor a separate ball table")
  eq(save.inventory.POTION, 3, "the ITEM pocket lands in the bag")
  eq(save.inventory.BICYCLE, 1, "so does KEY_ITEM, which is why you can cycle")
  eq(save.inventory.POKE_BALL, 9, "and BALL, which is why you can throw one")

  -- Save.summary does `save.position.map or save.spawn`, so a save with no
  -- map key resumes at the spawn point with the old coordinates.
  eq(save.position.map, "GOLDENROD_CITY", "position names the map it is on")

  -- save.pokedex.caught[species] = true, keyed the same way.
  local dexKey = next(save.pokedex.caught)
  check(dexKey == nil or type(dexKey) == "string" or type(dexKey) == "number",
    "the dex is keyed by species id")

  -- Save.scrubEvents runs tonumber over the VALUE against Save.EVENT_BYTES,
  -- and tonumber(true) is nil, so a set of booleans is silently emptied.
  eq(type(save.events[0]), "number", "events are packed bytes, not booleans")
  local evCount = 0
  for _ in pairs(save.events) do evCount = evCount + 1 end
  eq(evCount, Gen2Save.EVENT_BYTES, "one entry per event byte")

  -- 0 is truthy in Lua, so a raw status byte makes healthy mons look ill.
  eq(m.status, "brn", "status is the engine's class string")
  eq(save.boxes[3][1].status, nil, "and nil when healthy, not 0")
end

-- Without a crosswalk the raw numbers survive rather than being dropped: an id
-- this build cannot name is still the player's.
do
  local save = assert(Gen2Save.decode(build("gold"), "gold"))
  eq(save.party[1].species, 155, "an unknown species keeps its cart number")
end

-- ------------------------------------------------------------------
-- A save the real cartridge would open must not be refused
-- ------------------------------------------------------------------
--
-- TryLoadSaveFile checks the primary, and on failure VerifyBackupChecksum and
-- LoadBackupPlayerData. Refusing on the primary alone reports a save the game
-- itself would load as corrupt, which is what #1832 was about.

do
  local L = Gen2Save.layoutFor("crystal")
  check(L.backup ~= nil, "Crystal carries a backup layout")
  eq(Gen2Save.layoutFor("gold").backup, nil,
    "Gold and Silver split theirs across three sections, so they have none")

  local good = build("crystal")
  local at = L.sChecksum + 1
  local broken = good:sub(1, at - 1)
    .. string.char((good:byte(at) + 1) % 256) .. good:sub(at + 1)

  eq(Gen2Save.checksumValid(broken, L), false, "the primary is now corrupt")
  eq(Gen2Save.checksumValid(broken, L.backup), true, "the backup is not")
  local save, err = Gen2Save.decode(broken, "crystal")
  check(save ~= nil, "so the save still opens -- " .. tostring(err))
  if save then
    eq(save.player.name, "ASH", "and reads the same player out of the backup")
  end
end

-- ------------------------------------------------------------------
-- Gold's table is not Crystal's
-- ------------------------------------------------------------------

do
  local goldBytes = build("gold")
  local wrong, err = Gen2Save.decode(goldBytes, "crystal")
  check(wrong == nil, "a Gold save read with Crystal's table is refused")
  check(type(err) == "string" and err:find("checksum", 1, true) ~= nil,
    "and refused by the guard, not by luck -- got: " .. tostring(err))
  check(Gen2Layout.goldSilver.wPartyMons ~= Gen2Layout.crystal.wPartyMons,
    "the two layouts really do disagree about where the party is")
end

-- ------------------------------------------------------------------
-- Through the launcher's own entry point
-- ------------------------------------------------------------------

do
  local save, err = SaveConvert.importSav(build("gold"), "gold", "gold")
  check(save ~= nil, "importSav accepts a Gen 2 save now -- " .. tostring(err))
  if save then
    eq(save.player.name, "ASH", "and returns the decoded player")
    eq(save.generation, 2, "tagged as Gen 2")
    -- Everything the cart does not carry still has to be there.
    check(type(save.mail) == "table", "mail falls back to the new-game default")
    check(type(save.hallOfFame) == "table", "so does the hall of fame")
    check(type(save.phoneContacts) == "table", "and the phone book")
  end
  local _, expErr = SaveConvert.exportSav({ meta = {} }, "gold")
  check(type(expErr) == "string" and expErr:find("exporting", 1, true) ~= nil,
    "export is still refused, and says so -- got: " .. tostring(expErr))
end

-- ------------------------------------------------------------------
-- Real-save audit (fixture-gated)
-- ------------------------------------------------------------------

local fixture = os.getenv("POKEPORT_GEN2_SAV_FIXTURE")
local fixtureVersion = os.getenv("POKEPORT_GEN2_SAV_VERSION") or "crystal"
if not fixture then
  print("real-save audit skipped (set POKEPORT_GEN2_SAV_FIXTURE to a Gen 2 .sav, "
    .. "and POKEPORT_GEN2_SAV_VERSION to gold/silver/crystal)")
else
  local f = io.open(fixture, "rb")
  local bytes = f and f:read("*a")
  if f then f:close() end
  check(bytes ~= nil, "the fixture is readable")
  if bytes then
    local save, err = Gen2Save.decode(bytes, fixtureVersion)
    check(save ~= nil, "a real cart save decodes -- " .. tostring(err))
    if save then
      check(#save.party >= 1 and #save.party <= 6, "party size is possible")
      check(#save.player.name > 0, "the player has a name")
      for i, mon in ipairs(save.party) do
        check(mon.species >= 1 and mon.species <= Gen2Save.NUM_SPECIES,
          ("party %d species is a real species (%d)"):format(i, mon.species))
        check(mon.level >= 1 and mon.level <= 100,
          ("party %d level is possible (%d)"):format(i, mon.level))
        check(mon.dvs.attack <= 15 and mon.dvs.special <= 15,
          ("party %d DVs are nibbles"):format(i))
      end
      for b, box in ipairs(save.boxes) do
        check(#box <= Gen2Save.BOX_CAPACITY, ("box %d holds at most 20"):format(b))
      end
    end
  end
end

T.finish()