package game

import (
	"strings"
	"testing"
)

func genLevel(t *testing.T, seed int32) *RogueGame {
	t.Helper()
	g := NewGame(Config{Seed: seed})
	g.NewLevel()
	return g
}

// renderMap draws the raw level map (not the screen) as text.
func renderMap(g *RogueGame) string {
	var sb strings.Builder
	for y := 0; y < NumLines; y++ {
		for x := 0; x < NumCols; x++ {
			ch := g.Level.Char(y, x)
			if m := g.Level.MonsterAt(y, x); m != nil {
				ch = m.Type
			}
			sb.WriteByte(ch)
		}
		sb.WriteByte('\n')
	}
	return sb.String()
}

func TestNewLevelInvariants(t *testing.T) {
	for _, seed := range []int32{1, 12345, 2026, 99999} {
		g := genLevel(t, seed)

		// The staircase is somewhere real.
		st := g.Level.Stairs
		if g.Level.Char(st.Y, st.X) != Stairs {
			t.Errorf("seed %d: no staircase at recorded stairs position", seed)
		}

		// The hero stands on a walkable, monster-free cell.
		hp := g.Player.Pos
		if !stepOk(g.Level.Char(hp.Y, hp.X)) {
			t.Errorf("seed %d: hero on unwalkable cell %q", seed,
				g.Level.Char(hp.Y, hp.X))
		}
		if g.Level.MonsterAt(hp.Y, hp.X) != nil {
			t.Errorf("seed %d: hero standing on a monster", seed)
		}
		if g.Player.Room == nil {
			t.Errorf("seed %d: hero not in any room", seed)
		}

		// Some rooms exist and are drawn.
		m := renderMap(g)
		if !strings.Contains(m, "|") || !strings.Contains(m, "-") {
			t.Errorf("seed %d: no room walls drawn", seed)
		}
		if !strings.Contains(m, ".") && !strings.Contains(m, "#") {
			t.Errorf("seed %d: no floor or passages drawn", seed)
		}

		// Every monster is indexed on the map and placed in a room.
		for _, mon := range g.Level.Monsters {
			if g.Level.MonsterAt(mon.Pos.Y, mon.Pos.X) != mon {
				t.Errorf("seed %d: monster %c not indexed at its position",
					seed, mon.Type)
			}
			if mon.Room == nil {
				t.Errorf("seed %d: monster %c has no room", seed, mon.Type)
			}
		}

		// Every level object sits on a cell displaying its type (items can
		// share cells only with monsters standing on them).
		for _, obj := range g.Level.Objects {
			ch := g.Level.Char(obj.Pos.Y, obj.Pos.X)
			if ch != obj.Kind.Glyph() &&
				g.Level.MonsterAt(obj.Pos.Y, obj.Pos.X) == nil {
				t.Errorf("seed %d: object %v at (%d,%d) but map shows %q",
					seed, obj.Kind, obj.Pos.Y, obj.Pos.X, ch)
			}
		}

		// The player has her starting kit: food, armor, mace, bow, arrows.
		if len(g.Player.Pack) != 5 {
			t.Errorf("seed %d: starting pack has %d items, want 5",
				seed, len(g.Player.Pack))
		}
		if g.Player.CurWeapon == nil ||
			g.Player.CurWeapon.WeaponKind() != WeaponMace {
			t.Errorf("seed %d: not wielding the starting mace", seed)
		}
		if g.Player.CurArmor == nil ||
			g.Player.CurArmor.ArmorKind() != ArmorRingMail {
			t.Errorf("seed %d: not wearing the starting ring mail", seed)
		}
	}
}

func TestNewLevelDeterministic(t *testing.T) {
	a := renderMap(genLevel(t, 12345))
	b := renderMap(genLevel(t, 12345))
	if a != b {
		t.Error("same seed produced different levels")
	}
	c := renderMap(genLevel(t, 54321))
	if a == c {
		t.Error("different seeds produced identical levels")
	}
}

// TestDeeperLevels exercises generation across many depths and seeds —
// mazes, dark rooms, traps, treasure rooms — as a crash/invariant sweep.
func TestDeeperLevels(t *testing.T) {
	for _, seed := range []int32{7, 42, 1000, 31337} {
		g := NewGame(Config{Seed: seed})
		for depth := 1; depth <= 30; depth++ {
			g.Depth = depth
			g.NewLevel()
			st := g.Level.Stairs
			if g.Level.Char(st.Y, st.X) != Stairs {
				t.Fatalf("seed %d depth %d: missing staircase", seed, depth)
			}
		}
	}
}