using System;
using System.Collections.Generic;
using System.Linq;
namespace PKHeX.Core;
///
/// Logic for finding a from inputs.
///
public static class FrameFinder
{
///
/// Checks a to see if any encounter frames can generate the spread. Requires further filtering against matched Encounter Slots and generation patterns.
///
/// Matched containing info and .
/// object containing various accessible information required for the encounter.
/// to yield possible encounter details for further filtering
public static IEnumerable GetFrames(PIDIV pidiv, PKM pk)
{
if (pk.Version == (int)GameVersion.CXD)
return Array.Empty();
var info = new FrameGenerator(pk) {Nature = pk.EncryptionConstant % 25};
var seeds = GetSeeds(pidiv, info, pk);
var frames = pidiv.Type == PIDType.CuteCharm
? FilterCuteCharm(seeds, info)
: FilterNatureSync(seeds, info);
return GetRefinedSeeds(frames, info, pidiv);
}
// gather possible nature determination seeds until a same-nature PID breaks the unrolling
private static IEnumerable GetSeeds(PIDIV pidiv, FrameGenerator info, PKM pk)
{
if (pk.Species == (int)Species.Unown && pk.FRLG) // Gen3 FRLG Unown: reversed await case
return SeedInfo.GetSeedsUntilUnownForm(pidiv, info, pk.Form);
if (pidiv.Type == PIDType.CuteCharm && info.FrameType != FrameType.MethodH) // Gen4: ambiguous seed due to gender-buffered PID
return SeedInfo.GetSeedsUntilNature4Cute(pk);
return SeedInfo.GetSeedsUntilNature(pidiv, info);
}
private static IEnumerable GetRefinedSeeds(IEnumerable frames, FrameGenerator info, PIDIV pidiv)
{
var refined = RefineFrames(frames, info);
if (pidiv.Type == PIDType.CuteCharm && info.FrameType != FrameType.MethodH) // only permit cute charm successful frames
return refined.Where(z => (z.Lead & ~LeadRequired.UsesLevelCall) == LeadRequired.CuteCharm);
return refined;
}
private static IEnumerable RefineFrames(IEnumerable frames, FrameGenerator info)
{
return info.FrameType == FrameType.MethodH
? RefineFrames3(frames, info)
: RefineFrames4(frames, info);
}
private static IEnumerable RefineFrames3(IEnumerable frames, FrameGenerator info)
{
// ESV
// Level
// Nature
// Current Seed of the frame is the Level Calc (frame before nature)
var list = new List();
foreach (var f in frames)
{
bool noLead = !info.AllowLeads && f.Lead != LeadRequired.None;
if (noLead)
continue;
var prev = info.RNG.Prev(f.Seed); // ESV
var rand = prev >> 16;
f.RandESV = rand;
f.RandLevel = f.Seed >> 16;
f.OriginSeed = info.RNG.Prev(prev);
if (f.Lead != LeadRequired.CuteCharm) // needs proc checking
yield return f;
// Generate frames for other slots after the regular slots
if (info.AllowLeads && (f.Lead is LeadRequired.CuteCharm or LeadRequired.None))
list.Add(f);
}
foreach (var f in list)
{
var leadframes = GenerateLeadSpecificFrames3(f, info);
foreach (var frame in leadframes)
yield return frame;
}
}
private static IEnumerable GenerateLeadSpecificFrames3(Frame f, FrameGenerator info)
{
// Check leads -- none in list if leads are not allowed
// Certain leads inject a RNG call
// 3 different rand places
LeadRequired lead;
var prev0 = f.Seed; // 0
var prev1 = info.RNG.Prev(f.Seed); // -1
var prev2 = info.RNG.Prev(prev1); // -2
var prev3 = info.RNG.Prev(prev2); // -3
// Rand call raw values
var p0 = prev0 >> 16;
var p1 = prev1 >> 16;
var p2 = prev2 >> 16;
// Cute Charm
// -2 ESV
// -1 Level
// 0 CC Proc (Random() % 3 != 0)
// 1 Nature
if (info.Gendered)
{
bool cc = p0 % 3 != 0;
if (f.Lead == LeadRequired.CuteCharm) // 100% required for frame base
{
if (cc)
yield return info.GetFrame(prev2, LeadRequired.CuteCharm, p2, p1, prev3);
yield break;
}
lead = cc ? LeadRequired.CuteCharm : LeadRequired.CuteCharmFail;
yield return info.GetFrame(prev2, lead, p2, p1, prev3);
}
if (f.Lead == LeadRequired.CuteCharm)
yield break;
// Pressure, Hustle, Vital Spirit = Force Maximum Level from slot
// -2 ESV
// -1 Level
// 0 LevelMax proc (Random() & 1)
// 1 Nature
bool max = p0 % 2 == 1;
lead = max ? LeadRequired.PressureHustleSpirit : LeadRequired.PressureHustleSpiritFail;
yield return info.GetFrame(prev2, lead, p2, p1, prev3);
// Keen Eye, Intimidate (Not compatible with Sweet Scent)
// -2 ESV
// -1 Level
// 0 Level Adequate Check !(Random() % 2 == 1) rejects -- rand%2==1 is adequate
// 1 Nature
// Note: if this check fails, the encounter generation routine is aborted.
if (max) // same result as above, no need to recalculate
{
lead = LeadRequired.IntimidateKeenEye;
yield return info.GetFrame(prev2, lead, p2, p1, prev3);
}
// Static or Magnet Pull
// -2 SlotProc (Random % 2 == 0)
// -1 ESV (select slot)
// 0 Level
// 1 Nature
bool force = p2 % 2 == 0;
if (force)
{
// Since a failed proc is indistinguishable from the default frame calls, only generate if it succeeds.
lead = LeadRequired.StaticMagnet;
yield return info.GetFrame(prev2, lead, p1, p0, prev3);
}
}
private static IEnumerable RefineFrames4(IEnumerable frames, FrameGenerator info)
{
var list = new List();
foreach (var f in frames)
{
// Current Seed of the frame is the ESV.
var rand = f.Seed >> 16;
f.RandESV = rand;
f.RandLevel = rand; // unused
f.OriginSeed = info.RNG.Prev(f.Seed);
yield return f;
// Create a copy for level; shift ESV and origin back
var esv = f.OriginSeed >> 16;
var origin = info.RNG.Prev(f.OriginSeed);
var withLevel = info.GetFrame(f.Seed, f.Lead | LeadRequired.UsesLevelCall, esv, f.RandLevel, origin);
yield return withLevel;
if (f.Lead != LeadRequired.None)
continue;
// Generate frames for other slots after the regular slots
list.Add(f);
}
foreach (var f in list)
{
var leadframes = GenerateLeadSpecificFrames4(f, info);
foreach (var frame in leadframes)
yield return frame;
}
}
private static IEnumerable GenerateLeadSpecificFrames4(Frame f, FrameGenerator info)
{
LeadRequired lead;
var prev0 = f.Seed; // 0
var prev1 = info.RNG.Prev(f.Seed); // -1
var prev2 = info.RNG.Prev(prev1); // -2
var prev3 = info.RNG.Prev(prev2); // -3
// Rand call raw values
var p0 = prev0 >> 16;
var p1 = prev1 >> 16;
var p2 = prev2 >> 16;
// Cute Charm
// -2 ESV
// -1 Level (Optional)
// 0 CC Proc (Random() % 3 != 0)
// 1 Nature
if (info.Gendered)
{
bool cc = (info.DPPt ? p0 / 0x5556 : p0 % 3) != 0;
if (f.Lead == LeadRequired.CuteCharm) // 100% required for frame base
{
if (!cc) yield break;
yield return info.GetFrame(prev2, LeadRequired.CuteCharm, p1, p1, prev2);
yield return info.GetFrame(prev2, LeadRequired.CuteCharm | LeadRequired.UsesLevelCall, p2, p1, prev3);
yield break;
}
lead = cc ? LeadRequired.CuteCharm : LeadRequired.CuteCharmFail;
yield return info.GetFrame(prev2, lead, p1, p1, prev2);
yield return info.GetFrame(prev2, lead | LeadRequired.UsesLevelCall, p2, p1, prev3);
}
if (f.Lead == LeadRequired.CuteCharm)
yield break;
// Pressure, Hustle, Vital Spirit = Force Maximum Level from slot
// -2 ESV
// -1 Level (Optional)
// 0 LevelMax proc (Random() & 1)
// 1 Nature
bool max = (info.DPPt ? p0 >> 15 : p0 & 1) == 1;
lead = max ? LeadRequired.PressureHustleSpirit : LeadRequired.PressureHustleSpiritFail;
yield return info.GetFrame(prev2, lead, p1, p1, prev2);
yield return info.GetFrame(prev2, lead | LeadRequired.UsesLevelCall, p2, p1, prev3);
// Keen Eye, Intimidate (Not compatible with Sweet Scent)
// -2 ESV
// -1 Level (Optional)
// 0 Level Adequate Check !(Random() % 2 == 1) rejects -- rand%2==1 is adequate
// 1 Nature
// Note: if this check fails, the encounter generation routine is aborted.
if (max) // same result as above, no need to recalculate
{
lead = LeadRequired.IntimidateKeenEye;
yield return info.GetFrame(prev2, lead, p1, p1, prev2);
yield return info.GetFrame(prev2, lead | LeadRequired.UsesLevelCall, p2, p1, prev3);
}
// Static or Magnet Pull
// -2 SlotProc (Random % 2 == 0)
// -1 ESV (select slot)
// 0 Level (Optional)
// 1 Nature
var force1 = (info.DPPt ? p1 >> 15 : p1 & 1) == 1;
lead = force1 ? LeadRequired.StaticMagnet : LeadRequired.StaticMagnetFail;
yield return info.GetFrame(prev2, lead, p0, p0, prev3);
var force2 = (info.DPPt ? p2 >> 15 : p2 & 1) == 1;
lead = (force2 ? LeadRequired.StaticMagnet : LeadRequired.StaticMagnetFail) | LeadRequired.UsesLevelCall;
yield return info.GetFrame(prev2, lead, p1, p0, prev3);
}
///
/// Filters the input according to a Nature Lock frame generation pattern.
///
/// Seed Information for the frame
/// Search Info for the frame
/// Possible matches to the Nature Lock frame generation pattern
private static IEnumerable FilterNatureSync(IEnumerable seeds, FrameGenerator info)
{
foreach (var seed in seeds)
{
var s = seed.Seed;
if (info.Safari3)
{
// successful pokeblock activation
bool result = IsValidPokeBlockNature(s, info.Nature, out uint blockSeed);
if (result)
yield return info.GetFrame(blockSeed, seed.Charm3 ? LeadRequired.CuteCharm : LeadRequired.None);
// if no pokeblocks present (or failed call), fall out of the safari specific code and generate via the other scenarios
}
var rand = s >> 16;
bool sync = info.AllowLeads && !seed.Charm3 && (info.DPPt ? rand >> 15 : rand & 1) == 0;
bool reg = (info.DPPt ? rand / 0xA3E : rand % 25) == info.Nature;
if (!sync && !reg) // doesn't generate nature frame
continue;
uint prev = RNG.LCRNG.Prev(s);
if (info.AllowLeads && reg) // check for failed sync
{
var failsync = (info.DPPt ? prev >> 31 : (prev >> 16) & 1) != 1;
if (failsync)
yield return info.GetFrame(RNG.LCRNG.Prev(prev), LeadRequired.SynchronizeFail);
}
if (sync)
yield return info.GetFrame(prev, LeadRequired.Synchronize);
if (reg)
{
if (seed.Charm3)
{
yield return info.GetFrame(prev, LeadRequired.CuteCharm);
}
else
{
if (info.Safari3)
prev = RNG.LCRNG.Prev(prev); // wasted RNG call
yield return info.GetFrame(prev, LeadRequired.None);
}
}
}
}
private static bool IsValidPokeBlockNature(uint seed, uint nature, out uint natureOrigin)
{
if (nature % 6 == 0) // neutral
{
natureOrigin = 0;
return false;
}
// unroll the RNG to a stack of seeds
var stack = new Stack();
for (uint i = 0; i < 25; i++)
{
for (uint j = 1 + i; j < 25; j++)
stack.Push(seed = RNG.LCRNG.Prev(seed));
}
natureOrigin = RNG.LCRNG.Prev(stack.Peek());
if (natureOrigin >> (16 % 100) >= 80) // failed proc
return false;
// init natures
uint[] natures = new uint[25];
for (uint i = 0; i < 25; i++)
natures[i] = i;
// shuffle nature list
for (uint i = 0; i < 25; i++)
{
for (uint j = 1 + i; j < 25; j++)
{
var s = stack.Pop();
if (((s >> 16) & 1) == 0)
continue; // only swap if 1
(natures[i], natures[j]) = (natures[j], natures[i]);
}
}
var likes = Pokeblock.GetLikedBlockFlavor(nature);
// best case scenario is a perfect flavored pokeblock for the nature.
// has liked flavor, and all other non-disliked flavors are present.
// is it possible to skip this step?
for (int i = 0; i < 25; i++)
{
var n = natures[i];
if (n == nature)
break;
var nl = Pokeblock.GetLikedBlockFlavor(natures[i]);
if (nl == likes) // next random nature likes the same block as the desired nature
return false; // current nature is chosen instead, fail!
}
// unroll once more to hit the level calc (origin with respect for beginning the nature calcs)
natureOrigin = RNG.LCRNG.Prev(natureOrigin);
return true;
}
///
/// Filters the input according to a Cute Charm frame generation pattern.
///
/// Seed Information for the frame
/// Search Info for the frame
/// Possible matches to the Cute Charm frame generation pattern
private static IEnumerable FilterCuteCharm(IEnumerable seeds, FrameGenerator info)
{
foreach (var seed in seeds)
{
var s = seed.Seed;
var rand = s >> 16;
var nature = info.DPPt ? rand / 0xA3E : rand % 25;
if (nature != info.Nature)
continue;
var prev = RNG.LCRNG.Prev(s);
var proc = prev >> 16;
bool charmProc = (info.DPPt ? proc / 0x5556 : proc % 3) != 0; // 2/3 odds
if (!charmProc)
continue;
yield return info.GetFrame(RNG.LCRNG.Prev(prev), LeadRequired.CuteCharm);
}
}
}