import os
import json
import subprocess
import sys
import pytest

from lib_py.layout import (
    compute_2xk_layout,
    extract_panes_and_focus,
    LayoutDecision,
    PaneInfo,
)


def test_empty_or_malformed_json_fallback():
    d = compute_2xk_layout({}, default_anchor_id="pane-123")
    assert d.target_pane_id == "pane-123"
    assert d.direction == "right"
    assert not d.is_overflow


def test_1_pane_split_down():
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 120, "height": 80}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=60, min_rows=20)
    assert d.target_pane_id == "p1"
    assert d.direction == "down"
    assert not d.is_overflow


def test_1_pane_height_constrained_splits_right():
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 160, "height": 30}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=60, min_rows=20)
    assert d.target_pane_id == "p1"
    assert d.direction == "right"
    assert not d.is_overflow


def test_1_pane_overflow():
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 50, "height": 30}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=60, min_rows=20)
    assert d.target_pane_id == "p1"
    assert d.direction == "overflow"
    assert d.is_overflow


def test_2_panes_to_3_panes_new_column_right():
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 160, "height": 40}},
                {"pane_id": "p2", "rect": {"x": 0, "y": 40, "width": 160, "height": 40}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=60, min_rows=20)
    assert d.target_pane_id == "p1"
    assert d.direction == "right"
    assert not d.is_overflow


def test_3_panes_to_4_panes_fill_singleton():
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 80, "height": 40}},
                {"pane_id": "p2", "rect": {"x": 0, "y": 40, "width": 80, "height": 40}},
                {"pane_id": "p3", "rect": {"x": 80, "y": 0, "width": 80, "height": 80}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=60, min_rows=20)
    assert d.target_pane_id == "p3"
    assert d.direction == "down"
    assert not d.is_overflow


def test_4_panes_to_5_panes_new_column():
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 120, "height": 40}},
                {"pane_id": "p2", "rect": {"x": 0, "y": 40, "width": 120, "height": 40}},
                {"pane_id": "p3", "rect": {"x": 120, "y": 0, "width": 120, "height": 40}},
                {"pane_id": "p4", "rect": {"x": 120, "y": 40, "width": 120, "height": 40}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=60, min_rows=20)
    assert d.target_pane_id == "p3"
    assert d.direction == "right"
    assert not d.is_overflow


def test_4_panes_overflow_when_width_constrained():
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 60, "height": 40}},
                {"pane_id": "p2", "rect": {"x": 0, "y": 40, "width": 60, "height": 40}},
                {"pane_id": "p3", "rect": {"x": 60, "y": 0, "width": 60, "height": 40}},
                {"pane_id": "p4", "rect": {"x": 60, "y": 40, "width": 60, "height": 40}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=60, min_rows=20)
    assert d.direction == "overflow"
    assert d.is_overflow


def test_max_columns_limit():
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 100, "height": 40}},
                {"pane_id": "p2", "rect": {"x": 0, "y": 40, "width": 100, "height": 40}},
                {"pane_id": "p3", "rect": {"x": 100, "y": 0, "width": 100, "height": 40}},
                {"pane_id": "p4", "rect": {"x": 100, "y": 40, "width": 100, "height": 40}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=30, min_rows=20, max_columns=2)
    assert d.direction == "overflow"
    assert d.is_overflow


def test_headless_0x0_transitions():
    # N=1 -> down
    p1 = {"result": {"panes": [{"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}}]}}
    assert compute_2xk_layout(p1).direction == "down"

    # N=2 -> right
    p2 = {"result": {"panes": [
        {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}},
        {"pane_id": "p2", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}}
    ]}}
    assert compute_2xk_layout(p2).direction == "right"

    # N=3 -> down
    p3 = {"result": {"panes": [
        {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}},
        {"pane_id": "p2", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}},
        {"pane_id": "p3", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}}
    ]}}
    assert compute_2xk_layout(p3).direction == "down"

    # N=4 -> right
    p4 = {"result": {"panes": [
        {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}},
        {"pane_id": "p2", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}},
        {"pane_id": "p3", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}},
        {"pane_id": "p4", "rect": {"x": 0, "y": 0, "width": 0, "height": 0}}
    ]}}
    assert compute_2xk_layout(p4).direction == "right"


def test_real_herdr_080_nested_layout_format():
    payload = {
        "result": {
            "layout": {
                "area": {"height": 78, "width": 120, "x": 26, "y": 1},
                "focused_pane_id": "wK:p1",
                "panes": [
                    {"pane_id": "wK:p1", "rect": {"height": 39, "width": 60, "x": 26, "y": 1, "focused": True}},
                    {"pane_id": "wK:p2", "rect": {"height": 39, "width": 60, "x": 26, "y": 40, "focused": False}},
                    {"pane_id": "wK:p3", "rect": {"height": 78, "width": 60, "x": 86, "y": 1, "focused": False}}
                ],
                "splits": [{"direction": "right", "id": "split_0_root", "ratio": 0.5}],
                "workspace_id": "wK",
                "tab_id": "wK:t1",
                "zoomed": False
            },
            "type": "pane_layout"
        }
    }
    d = compute_2xk_layout(payload, min_cols=30, min_rows=20)
    assert d.target_pane_id == "wK:p3"
    assert d.direction == "down"


def test_cli_invocation_pipe():
    payload = json.dumps({
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 120, "height": 80}}
            ]
        }
    })
    skills_dir = os.path.abspath(".agents/skills")
    env = {**os.environ, "PYTHONPATH": skills_dir}
    res = subprocess.run(
        [sys.executable, "-m", "lib_py.layout", "--min-cols", "60", "--min-rows", "20"],
        input=payload,
        capture_output=True,
        text=True,
        env=env
    )
    assert res.returncode == 0
    assert res.stdout.strip() == "down p1"

    res_json = subprocess.run(
        [sys.executable, "-m", "lib_py.layout", "--json"],
        input=payload,
        capture_output=True,
        text=True,
        env=env
    )
    assert res_json.returncode == 0
    data = json.loads(res_json.stdout)
    assert data["target_pane_id"] == "p1"
    assert data["direction"] == "down"
    assert not data["is_overflow"]


def test_lib_sh_no_local_in_shim_heredoc():
    """Verify F-1: No 'local' declarations inside the top-level shim heredoc dispatcher."""
    import os
    lib_path = os.path.abspath(".agents/skills/lib.sh")
    with open(lib_path, "r", encoding="utf-8") as f:
        content = f.read()

    start_idx = content.find("cat <<'EOF' > \"$tmp_file\"")
    end_idx = content.find("\nEOF\n", start_idx)
    assert start_idx != -1 and end_idx != -1

    heredoc = content[start_idx:end_idx]
    # Check specifically in the layout block
    layout_idx = heredoc.find('split_dir=""')
    assert layout_idx != -1
    layout_block = heredoc[layout_idx:layout_idx + 800]
    assert "local " not in layout_block, f"Forbidden 'local' found in top-level shim heredoc:\n{layout_block}"


def test_5_panes_to_6_panes_fill_singleton_in_3rd_column():
    """Verify 5 panes (2x2 full + 1 singleton in 3rd col) -> splits 3rd col singleton down to make 2x3 grid."""
    payload = {
        "result": {
            "panes": [
                {"pane_id": "p1", "rect": {"x": 0, "y": 0, "width": 80, "height": 40}},
                {"pane_id": "p2", "rect": {"x": 0, "y": 40, "width": 80, "height": 40}},
                {"pane_id": "p3", "rect": {"x": 80, "y": 0, "width": 80, "height": 40}},
                {"pane_id": "p4", "rect": {"x": 80, "y": 40, "width": 80, "height": 40}},
                {"pane_id": "p5", "rect": {"x": 160, "y": 0, "width": 80, "height": 80}}
            ]
        }
    }
    d = compute_2xk_layout(payload, min_cols=60, min_rows=20)
    assert d.target_pane_id == "p5"
    assert d.direction == "down"
    assert not d.is_overflow


def test_lib_sh_layout_split_in_set_e_subshell(tmp_path):
    """Verify F-1 & F-2: lib.sh layout split block executes cleanly in set -euo pipefail top-level script."""
    import os
    skills_dir = os.path.abspath(".agents/skills")
    script = f"""#!/usr/bin/env bash
set -euo pipefail
export PYTHONPATH="{skills_dir}"

_real_herdr() {{
  if [ "${{1:-}}" = "pane" ] && [ "${{2:-}}" = "layout" ]; then
    echo '{{"result": {{"panes": [{{"pane_id": "p1", "rect": {{"x": 0, "y": 0, "width": 120, "height": 80}}}}]}}}}'
    return 0
  fi
  return 1
}}

sample_pane="p1"
split_dir=""

# Exact snippet from lib.sh:429-435
if [ -n "$sample_pane" ]; then
  layout_raw=$(_real_herdr pane layout --pane "$sample_pane" 2>/dev/null || echo "")
  read -r split_dir split_target < <(printf '%s' "$layout_raw" | python3 -m lib_py.layout --min-cols "${{MAM_MIN_PANE_COLS:-60}}" --min-rows "${{MAM_MIN_PANE_ROWS:-20}}" --sample-pane "$sample_pane" 2>/dev/null || echo "right $sample_pane")
  split_dir="${{split_dir:-right}}"
  sample_pane="${{split_target:-$sample_pane}}"
fi

echo "SPLIT_DIR=$split_dir"
echo "SAMPLE_PANE=$sample_pane"
"""
    res = subprocess.run(["bash", "-c", script], capture_output=True, text=True)
    assert res.returncode == 0, f"Script failed with code {res.returncode}. Stderr: {res.stderr}"
    assert "SPLIT_DIR=down" in res.stdout
    assert "SAMPLE_PANE=p1" in res.stdout


def test_real_generated_shim_layout_split(tmp_path):
    """Verify generated shim executes layout.py without command not found or local aborts."""
    import os
    skills_dir = os.path.abspath(".agents/skills")
    ws_dir = str(tmp_path / "ws")
    os.makedirs(ws_dir, exist_ok=True)

    test_script = f"""#!/usr/bin/env bash
set -euo pipefail
export WORKSPACE_ROOT="{ws_dir}"
export SKILL_DIR="{skills_dir}"
source "{skills_dir}/lib.sh"

_init_herdr_isolation

shim_path="$WORKSPACE_ROOT/.mam/shim/herdr"
if [ ! -x "$shim_path" ]; then
  echo "ERROR: shim not generated or not executable" >&2
  exit 1
fi

# Verify no 'local ' inside the shim heredoc body
if grep -E '^[[:space:]]*local layout_' "$shim_path"; then
  echo "ERROR: 'local layout_' found in generated shim" >&2
  exit 1
fi
echo "SHIM_OK"
"""
    res = subprocess.run(["bash", "-c", test_script], capture_output=True, text=True)
    assert res.returncode == 0, f"Shim test failed: {res.stderr}"
    assert "SHIM_OK" in res.stdout