// SPDX-FileCopyrightText: Copyright (c) 2024-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: Apache-2.0

//! Tokenizer Tests
//!
//! This module contains tests for the Tokenizer.
//!
//! For each tokenizer we use in production, we should have either a url to or a local copy
//! of either the tokenizer.json or the .model file.
//!
//! For a small set of common prompts, we need to have a hashable representation of the the encoding
//! object. We will precompute the hashes for each of these prompts for each tokenizer and store them
//! in a hashmap. We will then use these hashes to test that the tokenizer is working correctly. This
//! will detect if upstream dependency changes result in different/new behavior.

use dynamo_llm::tokenizers::traits::{Decoder, Encoder, Tokenizer};
use dynamo_llm::tokenizers::*;
use rstest::rstest;
use std::collections::HashMap;
use std::path::Path;
use std::sync::Arc;

// ---------------------------------------------------------------------------
// Test data
// ---------------------------------------------------------------------------

const TEST_PROMPTS: [&str; 4] = [
    "deep learning is",
    "Deep learning is",
    "has anyone seen nemo lately",
    "another prompt",
];

const LONG_TEST_PROMPTS: [(&str, &str); 6] = [
    ("Tell me about the following text.", "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat."),
    ("Tell me about the following text.", "Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."),
    ("Tell me about the following text.", "Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt."),
    ("Tell me about the following text.", "Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem."),
    // Note(jthomson04): Ishan asked me to add this one.
    ("Tell me about the following text.", "In the ancient realm of Tennisia, the very magic of the land is drawn from the sport itself. Forehands light the skies, backhands carve the earth, and serves rumble like thunder across kingdoms. At the center of this balance lie four sacred Grand Slam relics: the Sapphire Trophy of Melbourne, the Emerald Chalice of Paris, the Ruby Crown of London, and the Diamond Orb of New York. Together, they keep the game's spirit alive.
    But the relics are scattered, guarded by champions of legendary skill. The first is the Fire King of Clay, ruler of the crimson courts, whose topspin arcs blaze high and heavy, scorching all who dare stand across from him. The second is the Tempest Trickster, master of the baseline fortress, whose footwork and precision can turn back any storm, and whose returns arrive as if pulled by invisible strings. The third is the Shadow-Dancer of the Highlands, a tactician who thrives in the long rallies of twilight, changing pace and spin until opponents lose their rhythm. The fourth and final guardian is a towering Diamond Titan, a net-charging colossus whose volleys shatter the air itself.
    Into this arena of gods steps the Silver-Wristed Knight — a player of impossible grace, whose game is an art form. His quest: to claim each relic not for glory, but to restore harmony to the rankings of the realm.
    He travels across the Kingdom of Clay, where the points stretch like marathons and the air tastes of iron; through the Grasslands of London, where the ball skids low and the margins are razor-thin; over the Hard Courts of the East, where rallies turn into duels of endurance; and finally to the Cathedral of Lights in New York, where night matches burn with fevered energy.
    Each battle is played under enchanted floodlights, the lines patrolled by spectral line judges whose calls are final. The crowd's roar swells with every break point, and the Silver-Wristed Knight's racket glows brightest when the match teeters at deuce. There are moments when doubt grips him — when his serve falters or his touch deserts him — but each challenge teaches a new stroke, culminating in the legendary Forehand of Dawn.
    When the last relic is claimed, he stands not as a conqueror but as a custodian of the game, knowing that rivalries forge the very magic he protects. The balance is restored — until the next season begins."),
    // Emoji stress test
    ("Tell me about the following text.", "😀😃😄😁😆🥹😅😂🤣🥲☺️😊😇🙂🙃😉🤩😎 🤪🥳🤓🙄🤪😵👻")
];

const MULTIBYTE_TEST_CASES: [&str; 14] = [
    "hello world",
    "deep learning is awesome",
    "The quick brown fox jumps over the lazy dog.",
    "line1\nline2\nline3",
    "你好世界",            // CJK: 3-byte UTF-8 chars
    "😀😃😄😁",            // Emoji: 4-byte UTF-8 chars
    "hello 你好 world 🌍", // Mixed ASCII + CJK + emoji
    "café résumé naïve",   // Latin with diacritics (2-byte UTF-8)
    "こんにちは",          // Japanese hiragana
    "Привет мир",          // Cyrillic
    "مرحبا",               // Arabic (RTL)
    "🧑‍💻👨‍👩‍👧‍👦",                // Emoji ZWJ sequences (complex multi-codepoint)
    "a你b😀c",             // Interleaved single-byte and multi-byte
    "",                    // Empty string
];

const STREAM_TEST_CASES: [(&str, &str); 8] = [
    ("hello world", "deep learning is great"),
    ("summarize:", "The quick brown fox jumps over the lazy dog."),
    ("hello world", "你好世界"),
    ("prompt:", "😀😃😄😁"),
    ("translate this:", "hello 你好 world 🌍"),
    ("text:", "café résumé naïve"),
    ("say:", "こんにちは"),
    ("input:", "🧑‍💻👨‍👩‍👧‍👦"),
];

// ---------------------------------------------------------------------------
// Tokenizer paths
// ---------------------------------------------------------------------------

const TINYLLAMA_TOKENIZER_PATH: &str = "tests/data/sample-models/TinyLlama_v1.1/tokenizer.json";
const MOCK_TIKTOKEN_DIR: &str = "tests/data/sample-models/mock-tiktoken";

fn tinyllama_tokenizer() -> Arc<dyn Tokenizer> {
    Arc::new(
        HuggingFaceTokenizer::from_file(TINYLLAMA_TOKENIZER_PATH)
            .expect("Failed to load HuggingFace tokenizer"),
    )
}

fn mock_tiktoken_tokenizer() -> Arc<dyn Tokenizer> {
    let path = Path::new(env!("CARGO_MANIFEST_DIR"))
        .join(MOCK_TIKTOKEN_DIR)
        .join("tiktoken.model");
    Arc::new(
        TikTokenTokenizer::from_file_auto(path.to_str().unwrap())
            .expect("Failed to load tiktoken tokenizer"),
    )
}

// ---------------------------------------------------------------------------
// Parameterized scenario tests — every tokenizer must pass all of these
// ---------------------------------------------------------------------------

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_encode_decode_roundtrip(#[case] tokenizer: Arc<dyn Tokenizer>) {
    for &text in TEST_PROMPTS.iter() {
        let encoding = tokenizer
            .encode(text)
            .unwrap_or_else(|e| panic!("Failed to encode '{text}': {e}"));
        assert!(!encoding.token_ids().is_empty());

        let decoded: String = tokenizer
            .decode(encoding.token_ids(), false)
            .unwrap_or_else(|e| panic!("Failed to decode '{text}': {e}"))
            .into();
        assert_eq!(decoded, text, "Roundtrip failed for: '{text}'");
    }
}

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_encode_decode_roundtrip_multibyte(#[case] tokenizer: Arc<dyn Tokenizer>) {
    for &text in MULTIBYTE_TEST_CASES.iter() {
        let encoding = tokenizer
            .encode(text)
            .unwrap_or_else(|e| panic!("Failed to encode '{text}': {e}"));

        let decoded: String = tokenizer
            .decode(encoding.token_ids(), false)
            .unwrap_or_else(|e| panic!("Failed to decode '{text}': {e}"))
            .into();
        assert_eq!(decoded, text, "Roundtrip failed for: '{text}'");
    }
}

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_batch_encode_roundtrip(#[case] tokenizer: Arc<dyn Tokenizer>) {
    let inputs = &["hello", "world", "deep learning"];
    let encodings = tokenizer
        .encode_batch(inputs)
        .expect("Failed to batch encode");
    assert_eq!(encodings.len(), inputs.len());

    for (encoding, &input) in encodings.iter().zip(inputs.iter()) {
        let decoded: String = tokenizer
            .decode(encoding.token_ids(), false)
            .expect("Failed to decode")
            .into();
        assert_eq!(decoded, input);
    }
}

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_sequence_append_and_decode(#[case] tokenizer: Arc<dyn Tokenizer>) {
    let text = TEST_PROMPTS[0];
    let encoding = tokenizer.encode(text).expect("Failed to encode prompt");

    // Append text and verify token count matches
    let mut sequence = Sequence::new(tokenizer.clone().into());
    sequence.append_text(text).expect("Failed to append prompt");
    assert_eq!(sequence.len(), encoding.token_ids().len());

    // Incremental token-by-token decode via Sequence::append_token_id
    let mut decoder = Sequence::new(tokenizer.clone().into());
    let mut output = String::new();
    for &token_id in encoding.token_ids() {
        let chunk = decoder
            .append_token_id(token_id)
            .expect("Failed to decode token_id");
        output.push_str(&chunk);
    }

    assert_eq!(decoder.len(), sequence.len());
    assert_eq!(decoder.token_ids(), sequence.token_ids());
    assert_eq!(output, text);
}

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_sequence_roundtrip_multibyte(#[case] tokenizer: Arc<dyn Tokenizer>) {
    // Skip empty string — Sequence doesn't produce output for zero tokens
    for &text in MULTIBYTE_TEST_CASES.iter().filter(|t| !t.is_empty()) {
        let encoding = tokenizer
            .encode(text)
            .unwrap_or_else(|e| panic!("Failed to encode '{text}': {e}"));

        let mut sequence = Sequence::new(tokenizer.clone().into());
        let mut output = String::new();
        for &token_id in encoding.token_ids() {
            let chunk = sequence
                .append_token_id(token_id)
                .unwrap_or_else(|e| panic!("append_token_id failed for '{text}': {e}"));
            output.push_str(&chunk);
        }
        assert_eq!(output, text, "Sequence roundtrip failed for: '{text}'");
    }
}

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_decode_stream_basic(#[case] tokenizer: Arc<dyn Tokenizer>) {
    let text = TEST_PROMPTS[0];
    let encoding = tokenizer.encode(text).expect("Failed to encode prompt");

    let mut stream = DecodeStream::new(tokenizer.clone(), &[], false);
    let mut output = String::new();
    for &token_id in encoding.token_ids() {
        if let Some(chunk) = stream.step(token_id).expect("Failed to decode token_id") {
            output.push_str(&chunk);
        }
    }
    assert_eq!(output, text);
}

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_decode_stream_with_prefill(#[case] tokenizer: Arc<dyn Tokenizer>) {
    for &(input_text, output_text) in LONG_TEST_PROMPTS.iter() {
        let input_encoding = tokenizer
            .encode(input_text)
            .unwrap_or_else(|e| panic!("Failed to encode prompt '{input_text}': {e}"));

        let output_encoding = tokenizer
            .encode(output_text)
            .unwrap_or_else(|e| panic!("Failed to encode output '{output_text}': {e}"));

        let mut stream = DecodeStream::new(tokenizer.clone(), input_encoding.token_ids(), false);

        let mut output = String::new();
        for &token_id in output_encoding.token_ids() {
            if let Some(chunk) = stream
                .step(token_id)
                .unwrap_or_else(|e| panic!("DecodeStream::step failed for '{output_text}': {e}"))
            {
                output.push_str(&chunk);
            }
        }

        assert_eq!(output.trim(), output_text.to_string());
    }
}

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_decode_stream_multibyte(#[case] tokenizer: Arc<dyn Tokenizer>) {
    for &(prompt, output_text) in STREAM_TEST_CASES.iter() {
        let prompt_encoding = tokenizer
            .encode(prompt)
            .unwrap_or_else(|e| panic!("Failed to encode prompt '{prompt}': {e}"));

        let output_encoding = tokenizer
            .encode(output_text)
            .unwrap_or_else(|e| panic!("Failed to encode output '{output_text}': {e}"));

        let mut stream = DecodeStream::new(tokenizer.clone(), prompt_encoding.token_ids(), false);

        let mut reassembled = String::new();
        for &token_id in output_encoding.token_ids() {
            if let Some(chunk) = stream
                .step(token_id)
                .unwrap_or_else(|e| panic!("DecodeStream::step failed for '{output_text}': {e}"))
            {
                reassembled.push_str(&chunk);
            }
        }

        assert_eq!(
            reassembled.trim(),
            output_text,
            "DecodeStream roundtrip failed for: '{output_text}'"
        );
    }
}

#[rstest]
#[case::huggingface(tinyllama_tokenizer())]
#[case::tiktoken(mock_tiktoken_tokenizer())]
fn test_hash_determinism(#[case] tokenizer: Arc<dyn Tokenizer>) {
    let prompts = &["hello world", "deep learning", "another prompt"];
    let hashes1 = compute_hashes_for_tokenizer(tokenizer.as_ref(), prompts);
    let hashes2 = compute_hashes_for_tokenizer(tokenizer.as_ref(), prompts);
    assert_eq!(hashes1, hashes2, "Hashes should be deterministic");
    assert!(hashes1.iter().all(|&h| h != 0), "Hashes should be non-zero");
}

// ---------------------------------------------------------------------------
// Tokenizer-specific tests (not parameterized)
// ---------------------------------------------------------------------------

fn compute_hashes_for_tokenizer<E: Encoder + ?Sized>(tokenizer: &E, prompts: &[&str]) -> Vec<u64> {
    prompts
        .iter()
        .map(|&prompt| {
            tokenizer
                .encode(prompt)
                .expect("Failed to encode prompt")
                .get_hash()
        })
        .collect()
}

const HF_TOKENIZERS_LOCAL: [&str; 1] = [TINYLLAMA_TOKENIZER_PATH];

const HASHES: [(&str, [u64; 4]); 1] = [(
    TINYLLAMA_TOKENIZER_PATH,
    [
        1209591529327510910,
        4181375434596349981,
        6245658446118930933,
        5097285695902185237,
    ],
)];

#[test]
fn compute_hashes_hf() {
    let hash_map: HashMap<&str, [u64; 4]> = HASHES.iter().cloned().collect();

    for &tokenizer_name in HF_TOKENIZERS_LOCAL.iter() {
        let tokenizer = HuggingFaceTokenizer::from_file(tokenizer_name)
            .expect("Failed to load HuggingFace tokenizer");

        let prompt_hashes = compute_hashes_for_tokenizer(&tokenizer, &TEST_PROMPTS);

        println!(
            "HF Tokenizer: {:?} Hashes: {:?}",
            tokenizer_name, prompt_hashes
        );

        assert_eq!(prompt_hashes, hash_map[tokenizer_name]);
    }
}

#[test]
fn test_decode_with_skip_special_tokens() {
    let tokenizer = HuggingFaceTokenizer::from_file(TINYLLAMA_TOKENIZER_PATH)
        .expect("Failed to load remote HuggingFace tokenizer");

    // Create a sequence with special tokens:
    // <s> (token_id: 1) + "Hello world" + </s> (token_id: 2)
    let text = "Hello world";
    let encoding = tokenizer.encode(text).expect("Failed to encode text");
    let mut token_ids = vec![1]; // <s>
    token_ids.extend(encoding.token_ids());
    token_ids.push(2); // </s>

    // Decode with skip_special_tokens = false (should keep special tokens)
    let decoded_with_special: String = tokenizer
        .decode(&token_ids, false)
        .expect("Failed to decode with skip_special_tokens=false")
        .into();

    // Decode with skip_special_tokens = true (should remove special tokens)
    let decoded_without_special: String = tokenizer
        .decode(&token_ids, true)
        .expect("Failed to decode with skip_special_tokens=true")
        .into();

    // Validate exact matches on the entire decoded strings
    assert_eq!(decoded_with_special, "<s> Hello world</s>");
    assert_eq!(decoded_without_special, "Hello world");
}

#[test]
fn test_tiktoken_create_from_file() {
    let path = Path::new(env!("CARGO_MANIFEST_DIR"))
        .join(MOCK_TIKTOKEN_DIR)
        .join("tiktoken.model");
    let tokenizer =
        create_tokenizer_from_file(path.to_str().unwrap()).expect("Failed to create tokenizer");

    let encoding = tokenizer
        .encode("hello")
        .expect("Failed to encode with factory-created tokenizer");
    assert!(!encoding.token_ids().is_empty());
}

#[test]
fn test_tiktoken_encoding_variant_is_sp() {
    let tokenizer = mock_tiktoken_tokenizer();
    let encoding = tokenizer.encode("hello world").expect("Failed to encode");
    match &encoding {
        Encoding::Sp(_) => {}
        other => panic!("Expected Encoding::Sp, got {:?}", other),
    }
}
