//! Property tests for cryptographic operations

#![allow(clippy::unwrap_used, clippy::expect_used)]

use super::config::*;
use super::generators::*;
use proptest::prelude::*;

proptest! {
    #![proptest_config(default_config())]

    /// Property: Key derivation produces consistent results
    #[test]
    fn key_derivation_consistency(
        secret in arb_bytes(32..33),
        label in "[a-z]{1,20}",
        context in arb_bytes(0..100),
    ) {
        // Simulate key derivation
        let mut derived1 = vec![0u8; 32];
        let mut derived2 = vec![0u8; 32];

        // Mock HKDF expand with index-dependent mixing
        for (i, byte) in derived1.iter_mut().enumerate() {
            *byte = secret[i % secret.len()]
                .wrapping_add(label.len() as u8)
                .wrapping_add(context.len() as u8)
                .wrapping_add(i as u8); // Add index for mixing
        }

        for (i, byte) in derived2.iter_mut().enumerate() {
            *byte = secret[i % secret.len()]
                .wrapping_add(label.len() as u8)
                .wrapping_add(context.len() as u8)
                .wrapping_add(i as u8);
        }

        // Property: Same inputs produce same outputs
        prop_assert_eq!(&derived1, &derived2,
            "Key derivation not deterministic");
    }

    /// Property: Packet number encoding sizes
    #[test]
    fn packet_number_encoding_sizes(
        pn in 0u64..1_000_000,
    ) {
        // Test that packet numbers are encoded with appropriate sizes
        let pn_len = if pn < 128 {
            1
        } else if pn < 32768 {
            2
        } else {
            4
        };

        // Property: Encoding length should be sufficient to hold the value
        let max_representable = match pn_len {
            1 => 127,
            2 => 32767,
            4 => u32::MAX as u64,
            _ => unreachable!(),
        };

        prop_assert!(pn <= max_representable,
            "Packet number {} exceeds capacity of {}-byte encoding", pn, pn_len);

        // Property: Encoding should be minimal (no smaller encoding works)
        if pn_len > 1 {
            let smaller_max = match pn_len {
                2 => 127,
                4 => 32767,
                _ => 0,
            };
            prop_assert!(pn > smaller_max,
                "Packet number {} could use smaller encoding", pn);
        }
    }

    /// Property: AEAD nonce uniqueness
    #[test]
    fn aead_nonce_uniqueness(
        num_packets in 1usize..100,
    ) {
        let base_nonce = [0u8; 12];
        let mut nonces = HashSet::new();

        // Use sequential packet numbers to ensure uniqueness
        for pn in 0..num_packets as u64 {
            let mut nonce = base_nonce;

            // XOR packet number into nonce (simplified)
            for i in 0..8 {
                nonce[4 + i] ^= ((pn >> (i * 8)) & 0xFF) as u8;
            }

            // Property: Each packet number produces unique nonce
            prop_assert!(nonces.insert(nonce),
                "Duplicate nonce for packet number {}", pn);
        }

        // Property: All nonces should be unique
        prop_assert_eq!(nonces.len(), num_packets);
    }

    /// Property: Header protection mask
    #[test]
    fn header_protection(
        first_byte in any::<u8>(),
        packet_number in 0u32..1_000_000,
        sample in arb_bytes(16..17),
    ) {
        // Simulate header protection (pn_length computed for validation but not used directly)
        let _pn_length = if packet_number < 128 { 1 }
                        else if packet_number < 32768 { 2 }
                        else { 4 };

        // Create mask from sample (simplified)
        let mut mask = [0u8; 5];
        for i in 0..5 {
            mask[i] = sample[i % sample.len()];
        }

        // Apply protection
        let protected_first = first_byte ^ (mask[0] & 0x0f);

        // Property: Protection should be reversible
        let unprotected_first = protected_first ^ (mask[0] & 0x0f);
        prop_assert_eq!(first_byte, unprotected_first,
            "Header protection not reversible");

        // Property: Only low 4 bits should be affected
        prop_assert_eq!(first_byte & 0xf0, protected_first & 0xf0,
            "Header protection affected high bits");
    }
}

proptest! {
    #![proptest_config(default_config())]

    /// Property: TLS message fragmentation
    #[test]
    fn tls_fragmentation(
        message in arb_bytes(0..10000),
        fragment_size in 100usize..1500,
    ) {
        if message.is_empty() {
            return Ok(());
        }

        // Fragment the message
        let mut fragments = vec![];
        let mut offset = 0;

        while offset < message.len() {
            let end = (offset + fragment_size).min(message.len());
            fragments.push(&message[offset..end]);
            offset = end;
        }

        // Property: All fragments together equal original
        let reconstructed: Vec<u8> = fragments.iter()
            .flat_map(|f| f.iter().copied())
            .collect();
        prop_assert_eq!(&reconstructed, &message,
            "Fragmentation lost data");

        // Property: No fragment exceeds size limit
        for fragment in &fragments {
            prop_assert!(fragment.len() <= fragment_size,
                "Fragment {} exceeds size limit {}", fragment.len(), fragment_size);
        }

        // Property: No empty fragments except possibly the last
        for (i, fragment) in fragments.iter().enumerate() {
            if i < fragments.len() - 1 {
                prop_assert!(!fragment.is_empty(),
                    "Empty fragment at position {}", i);
            }
        }
    }

    /// Property: Certificate validation chain
    #[test]
    fn cert_chain_validation(
        chain_length in 1usize..5,
        has_root in any::<bool>(),
    ) {
        // Simulate certificate chain validation
        let mut depth = 0;

        for i in 0..chain_length {
            depth = i;

            // Last cert should be root if has_root
            let is_root = has_root && i == chain_length - 1;

            if is_root {
                // Self-signed (no additional validation needed in simplified model)
                break;
            }
        }

        // Property: Chain depth should be reasonable
        prop_assert!(depth < 10, "Certificate chain too deep: {}", depth);

        // Property: Valid chains need root or trusted intermediate
        if chain_length > 0 {
            // Chain exists, validation would depend on trust anchors
            prop_assert!(depth < chain_length, "Depth should be within chain length");
        }
    }

    /// Property: Session ticket size limits
    #[test]
    fn session_ticket_size(
        ticket_data in arb_bytes(0..1000),
        age_add in any::<u32>(),
        nonce_len in 0usize..32,
    ) {
        // Calculate ticket size
        let base_size = 4 + 4 + 2; // age_add + lifetime + ticket_len
        let ticket_size = base_size + ticket_data.len() + nonce_len + 2; // +2 for extensions

        // Property: Ticket size should be reasonable
        prop_assert!(ticket_size < 65535, "Session ticket too large: {}", ticket_size);

        // Property: Nonce should be reasonable
        prop_assert!(nonce_len <= 255, "Nonce too long: {}", nonce_len);

        // Property: Age add should affect ticket properties
        let obfuscated_age = age_add.wrapping_add(1000); // Add 1 second
        prop_assert_ne!(obfuscated_age, 1000, "Age obfuscation failed");
    }
}

use std::collections::HashSet;
