# Player AI System Documentation

This document provides a comprehensive overview of the AI decision-making system for hockey players in the game, including detailed flowcharts showing how player states and behaviors are determined.

## Overview

The Player AI system uses a sophisticated Entity-Component-System (ECS) pattern with context-aware decision making. Each player has multiple layers of state management:

- **Physical State**: Position, velocity, energy, puck possession
- **AI State**: Current behavior, target, reaction timing
- **Game Context**: Team possession, puck location, game situation

## Core AI Decision Flow

```mermaid
flowchart TD
    A[Player Update Called] --> B{Is Goalie?}
    B -->|Yes| C[Update Goalie AI]
    B -->|No| D[Check Reaction Time]
    D --> E{Reaction Time Met?}
    E -->|No| F[Skip AI Update]
    E -->|Yes| G{Is Faceoff Active?}
    G -->|Yes| H[Handle Faceoff Positioning]
    G -->|No| I[Determine Puck Possession]
    I --> J{Who Has Puck?}
    J -->|My Team| K[Team Has Puck Behavior]
    J -->|Opponent Team| L[Opponent Has Puck Behavior]
    J -->|Loose Puck| M[Loose Puck Behavior]

    C --> N[Position in Crease]
    H --> O[Move to Faceoff Position]
    K --> P[Offensive Strategy]
    L --> Q[Defensive Strategy]
    M --> R[Puck Competition]

    F --> S[End Update]
    N --> S
    O --> S
    P --> S
    Q --> S
    R --> S
```

## Team Possession States

### When Team Has Puck

```mermaid
flowchart TD
    A[Team Has Puck] --> B{Do I Have Puck?}
    B -->|Yes| C[Offensive Behavior With Puck]
    B -->|No| D[Support Offensive Behavior]

    C --> E{Distance to Goal < 250?}
    E -->|Yes| F{Good Shooting Angle?}
    F -->|Yes| G{Distance < 150 OR Random < 0.5?}
    G -->|Yes| H[SHOOT]
    G -->|No| I[Consider Pass]
    F -->|No| I
    E -->|No| I

    I --> J{Teammate Closer to Goal?}
    J -->|Yes| K{Random < 0.7?}
    K -->|Yes| L[PASS to Closer Teammate]
    K -->|No| M[Check Pressure]
    J -->|No| M

    M --> N{Opponent Distance < 100?}
    N -->|Yes| O{Find Good Pass Target?}
    O -->|Yes| P{Random < 0.8?}
    P -->|Yes| Q[PASS to Best Target]
    P -->|No| R[ADVANCE to Goal]
    O -->|No| R
    N -->|No| R

    D --> S[Calculate Support Position]
    S --> T[Move to Support Position]

    H --> U[End Turn]
    L --> U
    Q --> U
    R --> U
    T --> U
```

### When Opponent Has Puck

```mermaid
flowchart TD
    A[Opponent Has Puck] --> B{Am I Closest Defender?}
    B -->|Yes| C[Aggressive Pressure]
    B -->|No| D[Defensive Positioning]

    C --> E[Target Puck Carrier]
    C --> F[Set Behavior: aggressive_pressure]

    D --> G[Calculate Defend Position]
    D --> H[Set Behavior: defending]

    E --> I[End Turn]
    F --> I
    G --> I
    H --> I
```

### When Puck is Loose

```mermaid
flowchart TD
    A[Puck is Loose] --> B{Am I Closest to Puck?}
    B -->|Yes| C{Distance < 200?}
    C -->|Yes| D[Chase Puck]
    C -->|No| E[Formation Position]
    B -->|No| E

    D --> F[Set Behavior: chasing]
    E --> G[Calculate Formation Position]
    E --> H[Set Behavior: formation]

    F --> I[End Turn]
    G --> I
    H --> I
```

## Formation System

### Team State Determination

```mermaid
flowchart TD
    A[Determine Team State] --> B{Does Teammate Have Puck?}
    B -->|Yes| C[ATTACKING]
    B -->|No| D{Does Opponent Have Puck?}
    D -->|Yes| E[DEFENDING]
    D -->|No| F[Check Puck Location]

    F --> G{Team Side}
    G -->|Home| H{Puck X > 67% Width?}
    G -->|Away| I{Puck X < 33% Width?}

    H -->|Yes| C
    H -->|No| E
    I -->|Yes| C
    I -->|No| E
```

### Position Calculation by Role

```mermaid
flowchart TD
    A[Calculate Position] --> B{Team State}
    B -->|Attacking| C[Attacking Formation]
    B -->|Defending| D[Defending Formation]

    C --> E{Player Role}
    E -->|Center| F[Attack Zone, Center Y]
    E -->|Left Wing| G[Attack Zone - 50, Center Y - 120]
    E -->|Right Wing| H[Attack Zone - 50, Center Y + 120]
    E -->|Left Defense| I[Attack Zone - 150, Center Y - 80]
    E -->|Right Defense| J[Attack Zone - 150, Center Y + 80]

    D --> K{Player Role}
    K -->|Center| L[Defense Zone, Center Y]
    K -->|Left Wing| M[Defense Zone + Side*50, Center Y - 100]
    K -->|Right Wing| N[Defense Zone + Side*50, Center Y + 100]
    K -->|Left Defense| O[Defense Zone + Side*100, Center Y - 60]
    K -->|Right Defense| P[Defense Zone + Side*100, Center Y + 60]

    F --> Q[Apply Puck Influence]
    G --> Q
    H --> Q
    I --> Q
    J --> Q
    L --> Q
    M --> Q
    N --> Q
    O --> Q
    P --> Q

    Q --> R[Clamp to Rink Bounds]
    R --> S[Final Position]
```

## Decision Making Algorithms

### Pass Target Selection

```mermaid
flowchart TD
    A[Find Best Pass Target] --> B[Loop Through Teammates]
    B --> C{Distance 50-300?}
    C -->|No| D[Skip Teammate]
    C -->|Yes| E[Check Pass Blocking]

    E --> F[Loop Through Opponents]
    F --> G{Opponent Blocks Pass Line?}
    G -->|Yes| H[Mark as Blocked]
    G -->|No| I[Continue Check]

    I --> J{More Opponents?}
    J -->|Yes| F
    J -->|No| K{Pass Blocked?}

    K -->|Yes| D
    K -->|No| L[Calculate Score]
    L --> M[Score = Skill / Distance]
    M --> N{Best Score So Far?}
    N -->|Yes| O[Update Best Target]
    N -->|No| P[Continue]

    D --> Q{More Teammates?}
    P --> Q
    O --> Q
    Q -->|Yes| B
    Q -->|No| R[Return Best Target]

    H --> D
```

### Shooting Decision

```mermaid
flowchart TD
    A[Check Shooting Angle] --> B[Calculate Direction to Goal]
    B --> C[Loop Through Opponents]
    C --> D{Opponent Distance < 150?}
    D -->|No| E[Skip Opponent]
    D -->|Yes| F[Calculate Direction to Opponent]
    F --> G[Calculate Dot Product]
    G --> H{Dot > 0.8 AND Distance < 80?}
    H -->|Yes| I[Shot Blocked]
    H -->|No| J{More Opponents?}

    E --> J
    J -->|Yes| C
    J -->|No| K[Clear Shot]

    I --> L[Return False]
    K --> M[Return True]
```

## Goalie AI System

```mermaid
flowchart TD
    A[Goalie Update] --> B[Calculate Goal Position]
    B --> C[Define Crease Area]
    C --> D{Puck Distance < 80?}
    D -->|Yes| E[Aggressive Position]
    D -->|No| F[Standard Position]

    E --> G[Lerp Between Puck and Goal (0.3)]
    F --> H[Goal + Offset Based on Puck Y]

    G --> I[Clamp to Crease Bounds]
    H --> I
    I --> J[Set Target Position]
```

## Faceoff Positioning

```mermaid
flowchart TD
    A[Faceoff Active] --> B{Player Role}
    B -->|Center| C[Position at Faceoff Dot]
    B -->|Left Wing| D[Outside Circle + Buffer, Left Side]
    B -->|Right Wing| E[Outside Circle + Buffer, Right Side]
    B -->|Left Defense| F[Well Outside, Left Side]
    B -->|Right Defense| G[Well Outside, Right Side]
    B -->|Goalie| H[Stay in Net]

    C --> I[Set as Faceoff Participant]
    D --> J[Legal Position Outside Circle]
    E --> J
    F --> J
    G --> J
    H --> J

    I --> K[Set Behavior: faceoff]
    J --> K
```

## AI Behavior States

The AI system uses several behavior states to track what each player is currently doing:

- **`aggressive_pressure`**: Actively pursuing the puck carrier
- **`defending`**: Positioning defensively between opponent and goal
- **`chasing`**: Moving directly toward loose puck
- **`formation`**: Moving to calculated formation position
- **`offensive_support`**: Supporting teammate with puck
- **`checking`**: Performing body check on opponent
- **`faceoff`**: Positioned for faceoff situation

## Key AI Features

### Reaction Time System
- Each player has a unique reaction time (50-150ms)
- Prevents all players from reacting simultaneously
- Creates more realistic, staggered decision making

### Energy Management
- Energy affects maximum speed
- Players with low energy (< 20) move 30% slower
- Energy recovers when moving slowly
- Creates realistic fatigue simulation

### Contextual Decision Making
- Decisions based on multiple factors: distance, player attributes, game situation
- Probabilistic choices add unpredictability
- Different strategies for different scenarios

### Formation Intelligence
- Dynamic formations based on puck possession
- Role-specific positioning (forwards vs defensemen)
- Puck influence affects positioning slightly
- Maintains team structure while allowing individual decisions

This AI system creates realistic hockey gameplay with players that react intelligently to game situations while maintaining team strategy and individual characteristics.