"""Tests for the restructured MemoryStore — pure file I/O layer."""

from datetime import datetime
import json
from pathlib import Path

import pytest

from nanobot.agent.memory import MemoryStore


@pytest.fixture
def store(tmp_path):
    return MemoryStore(tmp_path)


class TestMemoryStoreBasicIO:
    def test_read_memory_returns_empty_when_missing(self, store):
        assert store.read_memory() == ""

    def test_write_and_read_memory(self, store):
        store.write_memory("hello")
        assert store.read_memory() == "hello"

    def test_read_soul_returns_empty_when_missing(self, store):
        assert store.read_soul() == ""

    def test_write_and_read_soul(self, store):
        store.write_soul("soul content")
        assert store.read_soul() == "soul content"

    def test_read_user_returns_empty_when_missing(self, store):
        assert store.read_user() == ""

    def test_write_and_read_user(self, store):
        store.write_user("user content")
        assert store.read_user() == "user content"

    def test_get_memory_context_returns_empty_when_missing(self, store):
        assert store.get_memory_context() == ""

    def test_get_memory_context_returns_formatted_content(self, store):
        store.write_memory("important fact")
        ctx = store.get_memory_context()
        assert "Long-term Memory" in ctx
        assert "important fact" in ctx


class TestHistoryWithCursor:
    def test_append_history_returns_cursor(self, store):
        cursor = store.append_history("event 1")
        assert cursor == 1
        cursor2 = store.append_history("event 2")
        assert cursor2 == 2

    def test_append_history_includes_cursor_in_file(self, store):
        store.append_history("event 1")
        content = store.read_file(store.history_file)
        data = json.loads(content)
        assert data["cursor"] == 1

    def test_cursor_persists_across_appends(self, store):
        store.append_history("event 1")
        store.append_history("event 2")
        cursor = store.append_history("event 3")
        assert cursor == 3

    def test_read_unprocessed_history(self, store):
        store.append_history("event 1")
        store.append_history("event 2")
        store.append_history("event 3")
        entries = store.read_unprocessed_history(since_cursor=1)
        assert len(entries) == 2
        assert entries[0]["cursor"] == 2

    def test_read_unprocessed_history_returns_all_when_cursor_zero(self, store):
        store.append_history("event 1")
        store.append_history("event 2")
        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 2

    def test_compact_history_drops_oldest(self, tmp_path):
        store = MemoryStore(tmp_path, max_history_entries=2)
        store.append_history("event 1")
        store.append_history("event 2")
        store.append_history("event 3")
        store.append_history("event 4")
        store.append_history("event 5")
        store.compact_history()
        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 2
        assert entries[0]["cursor"] in {4, 5}


class TestDreamCursor:
    def test_initial_cursor_is_zero(self, store):
        assert store.get_last_dream_cursor() == 0

    def test_set_and_get_cursor(self, store):
        store.set_last_dream_cursor(5)
        assert store.get_last_dream_cursor() == 5

    def test_cursor_persists(self, store):
        store.set_last_dream_cursor(3)
        store2 = MemoryStore(store.workspace)
        assert store2.get_last_dream_cursor() == 3


class TestLegacyHistoryMigration:
    def test_read_unprocessed_history_handles_entries_without_cursor(self, store):
        """JSONL entries with cursor=1 are correctly parsed and returned."""
        store.history_file.write_text(
            '{"cursor": 1, "timestamp": "2026-03-30 14:30", "content": "Old event"}\n',
            encoding="utf-8")
        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 1
        assert entries[0]["cursor"] == 1

    def test_migrates_legacy_history_md_preserving_partial_entries(self, tmp_path):
        memory_dir = tmp_path / "memory"
        memory_dir.mkdir()
        legacy_file = memory_dir / "HISTORY.md"
        legacy_content = (
            "[2026-04-01 10:00] User prefers dark mode.\n\n"
            "[2026-04-01 10:05] [RAW] 2 messages\n"
            "[2026-04-01 10:04] USER: hello\n"
            "[2026-04-01 10:04] ASSISTANT: hi\n\n"
            "Legacy chunk without timestamp.\n"
            "Keep whatever content we can recover.\n"
        )
        legacy_file.write_text(legacy_content, encoding="utf-8")

        store = MemoryStore(tmp_path)
        fallback_timestamp = datetime.fromtimestamp(
            (memory_dir / "HISTORY.md.bak").stat().st_mtime,
        ).strftime("%Y-%m-%d %H:%M")

        entries = store.read_unprocessed_history(since_cursor=0)
        assert [entry["cursor"] for entry in entries] == [1, 2, 3]
        assert entries[0]["timestamp"] == "2026-04-01 10:00"
        assert entries[0]["content"] == "User prefers dark mode."
        assert entries[1]["timestamp"] == "2026-04-01 10:05"
        assert entries[1]["content"].startswith("[RAW] 2 messages")
        assert "USER: hello" in entries[1]["content"]
        assert entries[2]["timestamp"] == fallback_timestamp
        assert entries[2]["content"].startswith("Legacy chunk without timestamp.")
        assert store.read_file(store._cursor_file).strip() == "3"
        assert store.read_file(store._dream_cursor_file).strip() == "3"
        assert not legacy_file.exists()
        assert (memory_dir / "HISTORY.md.bak").read_text(encoding="utf-8") == legacy_content

    def test_migrates_consecutive_entries_without_blank_lines(self, tmp_path):
        memory_dir = tmp_path / "memory"
        memory_dir.mkdir()
        legacy_file = memory_dir / "HISTORY.md"
        legacy_content = (
            "[2026-04-01 10:00] First event.\n"
            "[2026-04-01 10:01] Second event.\n"
            "[2026-04-01 10:02] Third event.\n"
        )
        legacy_file.write_text(legacy_content, encoding="utf-8")

        store = MemoryStore(tmp_path)

        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 3
        assert [entry["content"] for entry in entries] == [
            "First event.",
            "Second event.",
            "Third event.",
        ]

    def test_raw_archive_stays_single_entry_while_following_events_split(self, tmp_path):
        memory_dir = tmp_path / "memory"
        memory_dir.mkdir()
        legacy_file = memory_dir / "HISTORY.md"
        legacy_content = (
            "[2026-04-01 10:05] [RAW] 2 messages\n"
            "[2026-04-01 10:04] USER: hello\n"
            "[2026-04-01 10:04] ASSISTANT: hi\n"
            "[2026-04-01 10:06] Normal event after raw block.\n"
        )
        legacy_file.write_text(legacy_content, encoding="utf-8")

        store = MemoryStore(tmp_path)

        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 2
        assert entries[0]["content"].startswith("[RAW] 2 messages")
        assert "USER: hello" in entries[0]["content"]
        assert entries[1]["content"] == "Normal event after raw block."

    def test_nonstandard_date_headers_still_start_new_entries(self, tmp_path):
        memory_dir = tmp_path / "memory"
        memory_dir.mkdir()
        legacy_file = memory_dir / "HISTORY.md"
        legacy_content = (
            "[2026-03-25–2026-04-02] Multi-day summary.\n"
            "[2026-03-26/27] Cross-day summary.\n"
        )
        legacy_file.write_text(legacy_content, encoding="utf-8")

        store = MemoryStore(tmp_path)
        fallback_timestamp = datetime.fromtimestamp(
            (memory_dir / "HISTORY.md.bak").stat().st_mtime,
        ).strftime("%Y-%m-%d %H:%M")

        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 2
        assert entries[0]["timestamp"] == fallback_timestamp
        assert entries[0]["content"] == "[2026-03-25–2026-04-02] Multi-day summary."
        assert entries[1]["timestamp"] == fallback_timestamp
        assert entries[1]["content"] == "[2026-03-26/27] Cross-day summary."

    def test_existing_history_jsonl_skips_legacy_migration(self, tmp_path):
        memory_dir = tmp_path / "memory"
        memory_dir.mkdir()
        history_file = memory_dir / "history.jsonl"
        history_file.write_text(
            '{"cursor": 7, "timestamp": "2026-04-01 12:00", "content": "existing"}\n',
            encoding="utf-8",
        )
        legacy_file = memory_dir / "HISTORY.md"
        legacy_file.write_text("[2026-04-01 10:00] legacy\n\n", encoding="utf-8")

        store = MemoryStore(tmp_path)

        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 1
        assert entries[0]["cursor"] == 7
        assert entries[0]["content"] == "existing"
        assert legacy_file.exists()
        assert not (memory_dir / "HISTORY.md.bak").exists()

    def test_empty_history_jsonl_still_allows_legacy_migration(self, tmp_path):
        memory_dir = tmp_path / "memory"
        memory_dir.mkdir()
        history_file = memory_dir / "history.jsonl"
        history_file.write_text("", encoding="utf-8")
        legacy_file = memory_dir / "HISTORY.md"
        legacy_file.write_text("[2026-04-01 10:00] legacy\n\n", encoding="utf-8")

        store = MemoryStore(tmp_path)

        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 1
        assert entries[0]["cursor"] == 1
        assert entries[0]["timestamp"] == "2026-04-01 10:00"
        assert entries[0]["content"] == "legacy"
        assert not legacy_file.exists()
        assert (memory_dir / "HISTORY.md.bak").exists()

    def test_migrates_legacy_history_with_invalid_utf8_bytes(self, tmp_path):
        memory_dir = tmp_path / "memory"
        memory_dir.mkdir()
        legacy_file = memory_dir / "HISTORY.md"
        legacy_file.write_bytes(
            b"[2026-04-01 10:00] Broken \xff data still needs migration.\n\n"
        )

        store = MemoryStore(tmp_path)

        entries = store.read_unprocessed_history(since_cursor=0)
        assert len(entries) == 1
        assert entries[0]["timestamp"] == "2026-04-01 10:00"
        assert "Broken" in entries[0]["content"]
        assert "migration." in entries[0]["content"]
