Design a Simple Animal Chess (Jungle/Dou Shou Qi) Engine

Context

You are to design and implement a minimal-but-correct engine for Animal Chess (also known as Jungle/Dou Shou Qi) using object-oriented principles. The engine should model the 9×7 board (with rivers, traps, and dens), define the animal pieces (Elephant, Lion, Tiger, Leopard, Wolf, Dog, Cat, Rat) with their movement and capture rules, and expose a small API to initialize a game, place pieces, compute moves, make moves, and display state. Include test cases that exercise board setup, a lion capture via a river jump, and a short multi-move sequence.

Make minimal, explicit assumptions if a rule is ambiguous.

Requirements

1. Pieces and Ranks
   • Define classes for: Elephant(8), Lion(7), Tiger(6), Leopard(5), Wolf(4), Dog(3), Cat(2), Rat(1).
   • Use inheritance and a common base class with owner, position, and rank.
2. Board
   • 9 rows × 7 columns grid.
   • Terrain tiles:
     • Land
     • Rivers: two 3×2 blocks at rows 3–5 and columns 1–2 (left river), and columns 4–5 (right river) using 0-based indices.
     • Dens: top den at (0,3), bottom den at (8,3).
     • Traps: top traps at (0,2), (1,3), (0,4); bottom traps at (8,2), (7,3), (8,4).
3. Movement and Capture Rules
   • Orthogonal moves by one tile for all pieces except Lion/Tiger can jump across river along rank/file to the first non-river square if no rat blocks any intervening river square.
   • Only the Rat may enter river tiles.
   • Den and traps:
     • A player cannot enter their own den; entering the opponent’s den is a win.
     • Being on the opponent’s trap reduces a piece’s effective rank to 0 for capture comparisons.
   • Capture rules:
     • Normally, a piece can capture an enemy piece on its destination square if the attacker’s effective rank ≥ defender’s effective rank.
     • Special cases:
       • Rat(1) can capture Elephant(8) when the rat is on land. Elephant cannot capture Rat anywhere.
       • A rat in water cannot capture a piece on land; a piece on land cannot capture a rat in water (only a rat in the same water can capture that rat).
4. API
   • Initialize/reset game and board.
   • Place a piece on the board (validating terrain constraints, e.g., non-rats cannot be placed into rivers).
   • Compute legal moves for a piece.
   • Make a move (apply capture and win conditions).
   • Display the board state as ASCII.
5. Tests
   • Board setup demonstration (place multiple pieces and render).
   • A lion river-jump capture.
   • A short multi-move sequence of alternating turns (at least three moves) that exercises river movement and blocking.