"""Tests for context_compactor.py — constants and prompt templates.
Uses mock imports to avoid loading the full app stack."""

import sys
from unittest.mock import MagicMock

# Mock heavy dependencies before importing
for mod in [
    'sqlalchemy', 'sqlalchemy.orm', 'sqlalchemy.ext', 'sqlalchemy.ext.declarative',
    'sqlalchemy.ext.hybrid', 'sqlalchemy.sql', 'sqlalchemy.sql.expression',
    'src.database',
    'core.models', 'core.database',
]:
    if mod not in sys.modules:
        sys.modules[mod] = MagicMock()

from src.context_compactor import (
    COMPACT_THRESHOLD,
    SELF_SUMMARY_SYSTEM_PROMPT,
    SUMMARY_MAX_TOKENS,
    trim_for_context,
)


class TestCompactThreshold:
    def test_value(self):
        assert COMPACT_THRESHOLD == 0.85

    def test_summary_max_tokens(self):
        assert SUMMARY_MAX_TOKENS == 1024


class TestSelfSummaryPrompt:
    def test_contains_goal_section(self):
        assert "### User Goal" in SELF_SUMMARY_SYSTEM_PROMPT

    def test_contains_what_was_done_section(self):
        assert "### What Was Done" in SELF_SUMMARY_SYSTEM_PROMPT

    def test_contains_current_state_section(self):
        assert "### Current State" in SELF_SUMMARY_SYSTEM_PROMPT

    def test_contains_pending_section(self):
        assert "### Pending / Next Steps" in SELF_SUMMARY_SYSTEM_PROMPT

    def test_contains_key_context_section(self):
        assert "### Key Context" in SELF_SUMMARY_SYSTEM_PROMPT

    def test_count_placeholder(self):
        assert "{count}" in SELF_SUMMARY_SYSTEM_PROMPT

    def test_n_placeholder(self):
        assert "{n}" in SELF_SUMMARY_SYSTEM_PROMPT

    def test_mentions_compactions(self):
        assert "Compactions so far" in SELF_SUMMARY_SYSTEM_PROMPT


class TestTrimForContext:
    def test_keeps_current_large_user_message_by_truncating(self):
        huge = "A" * 20000
        messages = [
            {"role": "system", "content": "You are helpful."},
            {"role": "user", "content": huge},
        ]

        trimmed = trim_for_context(messages, context_length=2048, reserve_tokens=512)

        user_msgs = [m for m in trimmed if m.get("role") == "user"]
        assert len(user_msgs) == 1
        content = user_msgs[0]["content"]
        assert "pasted message was too large" in content
        assert content.startswith("A")
        assert len(content) < len(huge)

    def test_drops_older_messages_before_latest_user_paste(self):
        huge = "B" * 12000
        messages = [{"role": "system", "content": "You are helpful."}]
        messages.extend({"role": "user", "content": f"old-{i} " + ("x" * 1000)} for i in range(8))
        messages.append({"role": "user", "content": huge})

        trimmed = trim_for_context(messages, context_length=2048, reserve_tokens=512)

        assert trimmed[-1]["role"] == "user"
        assert "pasted message was too large" in trimmed[-1]["content"]
        assert "old-0" not in "\n".join(str(m.get("content", "")) for m in trimmed)