"""Tests for repeated -r ranges: unit window intersection, plain item slicing."""

import asyncio
import json
from datetime import UTC, datetime

from kanta.serialization import JsonSerializer
from kanta.structs import META_FORMAT, ChangeRecord, Snapshot
from tests.support import Data, make_kanta

# The CLI reads files with its own JSON Kanta instance unless -k is given.
JSON = ("json", JsonSerializer)

T0 = datetime(2026, 1, 1, tzinfo=UTC)


def _run_cli(path, *args):
    from kanta.__main__ import main

    return main([str(path), *args])


def _build(path, increments=3):
    async def build():
        kanta = make_kanta(path, Data, JSON)
        await kanta.open(log=False)
        for i in range(increments):
            with kanta.transaction(f"inc{i}", log=False) as data:
                data.counter += 1
        await kanta.close()

    asyncio.run(build())


def test_plain_range_restricts_dump_to_last_printed(tmp_path, capsys):
    """The JSON dump holds the state after the last printed item."""
    path = tmp_path / "data.kantadb"
    _build(path)
    capsys.readouterr()

    # Items are bootstrap, inc0, inc1, inc2: 1:3 prints inc0 and inc1.
    assert _run_cli(path, "-r", "1:3", "-o", "-") == 0
    out = capsys.readouterr()
    assert "bootstrap" not in out.err
    assert "inc0" in out.err
    assert "inc1" in out.err
    assert "inc2" not in out.err
    # The dump is the state after inc1, the last printed record.
    assert json.loads(out.out) == {"users": {}, "counter": 2}

    # Inclusive end.
    assert _run_cli(path, "-r", "0..1") == 0
    err = capsys.readouterr().err
    assert "bootstrap" in err
    assert "inc0" in err
    assert "inc1" not in err


def test_plain_single_index(tmp_path, capsys):
    path = tmp_path / "data.kantadb"
    _build(path)
    capsys.readouterr()

    assert _run_cli(path, "-r", "0") == 0
    err = capsys.readouterr().err
    assert "bootstrap" in err
    assert "inc0" not in err

    # Negative index counts from the end of the filtered output.
    assert _run_cli(path, "-r", "-1") == 0
    err = capsys.readouterr().err
    assert "inc2" in err
    assert "inc1" not in err

    # A single index must exist; out of range is exit 2.
    assert _run_cli(path, "-r", "99") == 2
    assert "99" in capsys.readouterr().err


def test_plain_ranges_intersect(tmp_path, capsys):
    path = tmp_path / "data.kantadb"
    _build(path)
    capsys.readouterr()

    # [1:) and [:3) intersect to items 1 and 2.
    assert _run_cli(path, "-r", "1:", "-r", ":3") == 0
    err = capsys.readouterr().err
    assert "bootstrap" not in err
    assert "inc0" in err
    assert "inc1" in err
    assert "inc2" not in err

    # An empty intersection prints nothing, exit 0 (truncation, not error).
    assert _run_cli(path, "-r", ":1", "-r", "3:") == 0
    err = capsys.readouterr().err
    assert "inc" not in err
    assert "bootstrap" not in err


def test_plain_applies_after_grep(tmp_path, capsys):
    """Plain numbers index into what survives --grep, order-independently."""
    path = tmp_path / "data.kantadb"
    _build(path)
    capsys.readouterr()

    # Grep leaves inc0..inc2; plain 0 picks the first of those.
    assert _run_cli(path, "--grep", "inc", "-r", "0") == 0
    first = capsys.readouterr().err
    assert "inc0" in first
    assert "inc1" not in first
    assert "bootstrap" not in first

    assert _run_cli(path, "-r", "0", "--grep", "inc") == 0
    assert capsys.readouterr().err == first

    # Negative index from the filtered end.
    assert _run_cli(path, "--grep", "inc", "-r", "-1") == 0
    err = capsys.readouterr().err
    assert "inc2" in err
    assert "inc1" not in err


def test_unit_specs_intersect(tmp_path, capsys):
    path = tmp_path / "data.kantadb"
    _build(path)
    capsys.readouterr()

    # r1:r4 = bootstrap..inc1, r2:r5 = inc0..inc2; intersection is inc0, inc1.
    assert _run_cli(path, "-r", "r1:r4", "-r", "r2:r5", "-o", "-") == 0
    out = capsys.readouterr()
    assert "bootstrap" not in out.err
    assert "inc0" in out.err
    assert "inc1" in out.err
    assert "inc2" not in out.err
    # The replay end is the intersected window end (state after inc1).
    assert json.loads(out.out) == {"users": {}, "counter": 2}


def test_unit_and_plain_combine(tmp_path, capsys):
    """Unit window first, then plain slicing over the window's items."""
    path = tmp_path / "data.kantadb"
    _build(path)
    capsys.readouterr()

    # Window r2:r4 yields inc0, inc1; plain item 0 prints only inc0.
    assert _run_cli(path, "-r", "r2:r4", "-r", "0", "-o", "-") == 0
    out = capsys.readouterr()
    assert "inc0" in out.err
    assert "inc1" not in out.err
    # The dump is the state after the last printed item (inc0).
    assert json.loads(out.out) == {"users": {}, "counter": 1}


def test_context_expands_after_grep(tmp_path, capsys):
    """Context records come from the whole file, free of --grep."""
    path = tmp_path / "data.kantadb"
    _build(path, increments=5)
    capsys.readouterr()

    assert _run_cli(path, "--grep", "inc2", "--context", "1") == 0
    err = capsys.readouterr().err
    assert "inc1" in err
    assert "inc2" in err
    assert "inc3" in err
    assert "inc0" not in err
    assert "inc4" not in err
    assert "bootstrap" not in err

    # Context 0 (default) changes nothing.
    assert _run_cli(path, "--grep", "inc2") == 0
    err = capsys.readouterr().err
    assert "inc1" not in err
    assert "inc2" in err

    # Context is clamped at the start of the file.
    assert _run_cli(path, "--grep", "bootstrap", "--context", "2") == 0
    err = capsys.readouterr().err
    assert "bootstrap" in err
    assert "inc0" in err
    assert "inc1" in err
    assert "inc2" not in err


def test_context_expands_past_unit_window(tmp_path, capsys):
    """Context expands whatever a unit selection would show, past the window."""
    path = tmp_path / "data.kantadb"
    _build(path)
    capsys.readouterr()

    # -r r2 alone shows only inc0 (the record producing state 2); context 1
    # expands past the window to bootstrap and inc1, and the dump follows
    # the last printed record.
    assert _run_cli(path, "-r", "r2", "--context", "1", "-o", "-") == 0
    out = capsys.readouterr()
    assert "bootstrap" in out.err
    assert "inc0" in out.err
    assert "inc1" in out.err
    assert "inc2" not in out.err
    assert json.loads(out.out) == {"users": {}, "counter": 2}


def test_context_expands_snapshot_selection(tmp_path, capsys):
    """-r sN --context N shows the snapshot plus its neighbors."""
    path = tmp_path / "data.kantadb"
    serializer = JsonSerializer()
    framer = serializer.framer_cls()
    out_bytes = bytearray()
    out_bytes += framer.frame_change(
        serializer.encode(ChangeRecord(ts=T0, a="inc0", v=0, diff={"counter": 1})),
        record_offset=len(out_bytes),
    )
    snap = Snapshot(ts=T0, v=0, state={"counter": 1}, r=1, k=META_FORMAT)
    out_bytes += framer.frame_snapshot(
        serializer.encode(snap), record_offset=len(out_bytes)
    )
    out_bytes += framer.frame_change(
        serializer.encode(ChangeRecord(ts=T0, a="inc1", v=0, diff={"counter": 2})),
        record_offset=len(out_bytes),
    )
    path.write_bytes(bytes(out_bytes))
    capsys.readouterr()

    # Without context, s1 (the file starts with a change, so s0 is l0)
    # shows just the snapshot and its state.
    assert _run_cli(path, "-r", "s1", "-o", "-") == 0
    out = capsys.readouterr()
    assert "snapshot s1" in out.err
    assert "inc0" not in out.err
    assert json.loads(out.out) == {"counter": 1}

    # With context, the selection expands past the snapshot line.
    assert _run_cli(path, "-r", "s1", "--context", "1", "-o", "-") == 0
    out = capsys.readouterr()
    assert "inc0" in out.err
    assert "snapshot s1" in out.err
    assert "inc1" in out.err
    assert json.loads(out.out) == {"counter": 2}


def test_context_merges_overlaps(tmp_path, capsys):
    """Nearby matches share context instead of duplicating records."""
    path = tmp_path / "data.kantadb"
    _build(path, increments=5)
    capsys.readouterr()

    # Grep leaves inc0..inc4; plain 1:3 selects inc1, inc2; context 1
    # expands to inc0..inc3, each printed exactly once (overlaps merged).
    assert _run_cli(path, "--grep", "inc", "-r", "1:3", "--context", "1") == 0
    err = capsys.readouterr().err
    for action in ["inc0", "inc1", "inc2", "inc3"]:
        assert err.count(action) == 1
    assert "bootstrap" not in err
    assert "inc4" not in err


def test_grep_and_context_shift_dump_to_last_printed(tmp_path, capsys):
    """Grep and --context are display filters, but the dump follows the
    last printed record, so they move it too."""
    path = tmp_path / "data.kantadb"
    _build(path)
    capsys.readouterr()

    # Only inc1 prints; the dump is the state after inc1.
    assert _run_cli(path, "--grep", "inc1", "-o", "-") == 0
    out = capsys.readouterr()
    assert "inc0" not in out.err
    assert json.loads(out.out) == {"users": {}, "counter": 2}

    # Context extends the printout past the match; the dump follows it.
    assert _run_cli(path, "--grep", "inc1", "--context", "1", "-o", "-") == 0
    out = capsys.readouterr()
    assert "inc2" in out.err
    assert json.loads(out.out) == {"users": {}, "counter": 3}

    # Nothing printed: the dump falls back to the range-end state.
    assert _run_cli(path, "--grep", "zzz", "-o", "-") == 0
    out = capsys.readouterr()
    assert json.loads(out.out) == {"users": {}, "counter": 3}