"""Unit tests for `history_injection` helpers.

Pure functions, no claude / no filesystem. The seed-JSONL shape is regression
tested against the same minimal contract that `probe_jsonl_injection.py`
proved out empirically (see FINDINGS § *Native JSONL injection works on
--resume*).
"""

from __future__ import annotations

import json

import pytest

from claude_code_api.injection import (
    build_concat_prompt,
    build_seed_jsonl,
    hash_history,
)

# --- hash_history ---------------------------------------------------------


def test_hash_history_empty_is_stable() -> None:
    assert hash_history([]) == hash_history([])


def test_hash_history_distinguishes_content() -> None:
    a = [{"role": "user", "content": "hi"}]
    b = [{"role": "user", "content": "bye"}]
    assert hash_history(a) != hash_history(b)


def test_hash_history_ignores_block_key_order() -> None:
    """Two clients that serialize the same block in different key orders
    must collide. Canonical-JSON serialization handles this."""
    a = [
        {
            "role": "assistant",
            "content": [{"type": "tool_use", "id": "t1", "name": "echo", "input": {"x": 1}}],
        }
    ]
    b = [
        {
            "role": "assistant",
            "content": [{"input": {"x": 1}, "name": "echo", "id": "t1", "type": "tool_use"}],
        }
    ]
    assert hash_history(a) == hash_history(b)


def test_hash_history_rejects_unknown_role() -> None:
    with pytest.raises(ValueError, match="role"):
        hash_history([{"role": "system", "content": "x"}])


def test_hash_history_text_blocks_collide_with_string_form() -> None:
    """A bare string `content` and the equivalent single text block hash to
    DIFFERENT values. They represent the same semantic content but appear
    on the wire differently — the gateway must pick one form per role and
    stay consistent. We don't try to paper over that here."""
    a = [{"role": "user", "content": "hello"}]
    b = [{"role": "user", "content": [{"type": "text", "text": "hello"}]}]
    assert hash_history(a) != hash_history(b)


# --- build_seed_jsonl -----------------------------------------------------


def test_build_seed_jsonl_empty_is_empty_string() -> None:
    assert build_seed_jsonl([], session_id="s", cwd="/tmp") == ""


def test_build_seed_jsonl_two_records_for_one_turn() -> None:
    seed = build_seed_jsonl(
        [
            {"role": "user", "content": "My name is Beaver."},
            {"role": "assistant", "content": "Got it."},
        ],
        session_id="sid-1",
        cwd="/work",
    )
    lines = [json.loads(line) for line in seed.strip().splitlines()]
    assert len(lines) == 2
    user_rec, asst_rec = lines

    assert user_rec["type"] == "user"
    assert user_rec["sessionId"] == "sid-1"
    assert user_rec["cwd"] == "/work"
    assert user_rec["parentUuid"] is None
    assert user_rec["message"] == {"role": "user", "content": "My name is Beaver."}
    assert user_rec["isMeta"] is False
    assert "uuid" in user_rec and "timestamp" in user_rec

    assert asst_rec["type"] == "assistant"
    assert asst_rec["parentUuid"] == user_rec["uuid"]
    assert asst_rec["message"]["role"] == "assistant"
    assert asst_rec["message"]["content"] == [{"type": "text", "text": "Got it."}]
    assert asst_rec["message"]["stop_reason"] == "end_turn"
    assert asst_rec["sessionId"] == "sid-1"


def test_build_seed_jsonl_chains_parent_uuids_across_turns() -> None:
    """The parentUuid graph must form a linear chain across turns — that's
    how claude reconstructs conversation order on resume."""
    seed = build_seed_jsonl(
        [
            {"role": "user", "content": "u1"},
            {"role": "assistant", "content": "a1"},
            {"role": "user", "content": "u2"},
            {"role": "assistant", "content": "a2"},
        ],
        session_id="s",
        cwd="/tmp",
    )
    recs = [json.loads(line) for line in seed.strip().splitlines()]
    assert len(recs) == 4
    assert recs[0]["parentUuid"] is None
    assert recs[1]["parentUuid"] == recs[0]["uuid"]
    assert recs[2]["parentUuid"] == recs[1]["uuid"]
    assert recs[3]["parentUuid"] == recs[2]["uuid"]


def test_build_seed_jsonl_passes_list_content_through_for_user() -> None:
    """A user record with a tool_result block (the only list-form user
    content claude itself writes) must round-trip verbatim."""
    seed = build_seed_jsonl(
        [
            {
                "role": "user",
                "content": [
                    {"type": "tool_result", "tool_use_id": "t1", "content": "42"},
                ],
            }
        ],
        session_id="s",
        cwd="/tmp",
    )
    rec = json.loads(seed.strip())
    assert rec["message"]["content"] == [
        {"type": "tool_result", "tool_use_id": "t1", "content": "42"},
    ]


def test_build_seed_jsonl_rejects_unknown_role() -> None:
    with pytest.raises(ValueError, match="role"):
        build_seed_jsonl([{"role": "system", "content": "x"}], session_id="s", cwd="/tmp")


# --- build_concat_prompt --------------------------------------------------


def test_build_concat_prompt_empty_history_returns_just_last_user() -> None:
    assert build_concat_prompt([], "hello") == "hello"


def test_build_concat_prompt_renders_alternating_history() -> None:
    out = build_concat_prompt(
        [
            {"role": "user", "content": "u1"},
            {"role": "assistant", "content": "a1"},
            {"role": "user", "content": "u2"},
            {"role": "assistant", "content": "a2"},
        ],
        "u3",
    )
    assert "Previous conversation context:" in out
    assert "[User]: u1" in out
    assert "[Assistant]: a1" in out
    assert "[User]: u2" in out
    assert "[Assistant]: a2" in out
    assert "Continue from here. New user message: u3" in out
    # The new prompt must come after the history, not interleaved.
    assert out.index("[Assistant]: a2") < out.index("Continue from here")


def test_build_concat_prompt_flattens_text_blocks_and_skips_tools() -> None:
    """Content-as-list with text blocks gets flattened; tool blocks are
    skipped (they don't round-trip through stdin in any useful form)."""
    out = build_concat_prompt(
        [
            {
                "role": "assistant",
                "content": [
                    {"type": "text", "text": "hello"},
                    {"type": "tool_use", "id": "t1", "name": "x", "input": {}},
                    {"type": "text", "text": "world"},
                ],
            },
        ],
        "ping",
    )
    assert "[Assistant]: hello world" in out