#!/usr/bin/env python3
"""
Standard Mathematical Fractal Generator & Cryptographic Chain Verifier

This script provides two functional, objective programming tools:
1. A standard Julia Set generator that computes complex plane iterations and
   saves the resulting fractal visualization as a text-based ASCII art representation.
2. A basic cryptographic ledger simulation demonstrating how blocks of data are
   sequentially linked using standard SHA-256 hashing to verify integrity.
"""

import hashlib
import json
import time

# ==============================================================================
# 1. STANDARD CRYPTOGRAPHIC LEDGER SIMULATION
# ==============================================================================

class SimpleBlock:
    def __init__(self, index, previous_hash, timestamp, data):
        self.index = index
        self.previous_hash = previous_hash
        self.timestamp = timestamp
        self.data = data
        self.hash = self.calculate_hash()

    def calculate_hash(self):
        """Computes a standard SHA-256 hash of the block contents."""
        block_string = json.dumps({
            "index": self.index,
            "previous_hash": self.previous_hash,
            "timestamp": self.timestamp,
            "data": self.data
        }, sort_keys=True)
        return hashlib.sha256(block_string.encode('utf-8')).hexdigest()


class SimpleLedger:
    def __init__(self):
        self.chain = [self.create_genesis_block()]

    def create_genesis_block(self):
        """Initializes the chain with a standard static starting block."""
        return SimpleBlock(0, "0", 1718300000, "Genesis Data")

    def get_latest_block(self):
        return self.chain[-1]

    def add_data(self, data):
        """Appends a new block containing arbitrary verification data."""
        latest = self.get_latest_block()
        new_block = SimpleBlock(
            index=latest.index + 1,
            previous_hash=latest.hash,
            timestamp=int(time.time()),
            data=data
        )
        self.chain.append(new_block)
        return new_block

    def verify_integrity(self):
        """
        Walks the chain block-by-block to confirm that hashes match
        and the cryptographic sequence is unbroken.
        """
        for i in range(1, len(self.chain)):
            current = self.chain[i]
            previous = self.chain[i-1]

            # Recalculate hash to detect data tampering
            if current.hash != current.calculate_hash():
                return False, f"Block {i} data has been altered."

            # Verify the chain linkage
            if current.previous_hash != previous.hash:
                return False, f"Block {i} link to Block {i-1} is broken."

        return True, "Ledger integrity verified. Sequence is intact."


# ==============================================================================
# 2. JULIA SET FRACTAL GENERATOR (ASCII REPRESENTATION)
# ==============================================================================

def generate_ascii_julia(width=80, height=40, max_iter=30, c_real=-0.7, c_imag=0.27015):
    """
    Generates a standard Julia set fractal using the quadratic formula f(z) = z^2 + c.
    Outputs a text-based (ASCII) representation of the fractal boundaries.
    """
    # Define complex plane boundaries
    x_min, x_max = -1.5, 1.5
    y_min, y_max = -1.0, 1.0

    # ASCII scale representation
    chars = " .:-=+*#%@"

    output = []
    for y_img in range(height):
        row = ""
        # Map grid index to the imaginary component of z
        zy = y_min + (y_img / (height - 1)) * (y_max - y_min)
        for x_img in range(width):
            # Map grid index to the real component of z
            zx = x_min + (x_img / (width - 1)) * (x_max - x_min)

            z = complex(zx, zy)
            c = complex(c_real, c_imag)

            n = 0
            # Standard escape velocity check (divergence threshold = 2.0)
            while abs(z) <= 2.0 and n < max_iter:
                z = z**2 + c
                n += 1

            # Map iteration count to ASCII shading character
            char_index = int((n / max_iter) * (len(chars) - 1))
            row += chars[char_index]
        output.append(row)

    return "\n".join(output)


# ==============================================================================
# 3. EXECUTION CONTROL
# ==============================================================================

if __name__ == "__main__":
    print("=" * 80)
    print("                OBJECTIVE MATHEMATICS & LOGIC PLATFORM")
    print("=" * 80)

    # Execute and display the Julia Set Fractal
    print("\n[1] Generating Julia Set Fractal (c = -0.7 + 0.27i)...")
    print("-" * 80)
    fractal_text = generate_ascii_julia()
    print(fractal_text)
    print("-" * 80)
    print("Fractal computed successfully using standard complex iteration: z(n+1) = z(n)^2 + c")

    # Execute and verify the cryptographic chain simulation
    print("\n[2] Initializing Cryptographic Verification Ledger...")
    ledger = SimpleLedger()

    # Simulate adding records
    ledger.add_data("System initialization verified.")
    ledger.add_data("Parameter constraints checked.")
    ledger.add_data("Heartbeat event recorded.")

    # Audit sequence integrity
    is_valid, report = ledger.verify_integrity()
    print(f"Total blocks in ledger: {len(ledger.chain)}")
    print(f"Audit Status: {'PASS' if is_valid else 'FAIL'}")
    print(f"Audit Report: {report}")

    # Display sample block data
    print("\nSample block entry data (Block #2):")
    sample_block = ledger.chain[2]
    print(json.dumps({
        "Index": sample_block.index,
        "Timestamp": sample_block.timestamp,
        "Previous Hash": sample_block.previous_hash[:16] + "...",
        "Block Hash": sample_block.hash[:16] + "...",
        "Payload": sample_block.data
    }, indent=4))
    print("=" * 80)