"""Tests for flow.core.stow — GNU Stow-style tree folding/unfolding."""

import os
from pathlib import Path

import pytest

from flow.core.stow import LinkOperation, LinkTree, TreeFolder


@pytest.fixture
def temp_home(tmp_path):
    """Create a temporary home directory."""
    home = tmp_path / "home"
    home.mkdir()
    return home


@pytest.fixture
def temp_dotfiles(tmp_path):
    """Create a temporary dotfiles repository."""
    dotfiles = tmp_path / "dotfiles"
    dotfiles.mkdir()
    return dotfiles


def test_linktree_add_remove():
    """Test basic LinkTree operations."""
    tree = LinkTree()
    source = Path("/dotfiles/zsh/.zshrc")
    target = Path("/home/user/.zshrc")

    tree.add_link(target, source, "zsh", is_dir_link=False)
    assert target in tree.links
    assert tree.links[target] == source
    assert tree.packages[target] == "zsh"
    assert not tree.is_directory_link(target)

    tree.remove_link(target)
    assert target not in tree.links
    assert target not in tree.packages


def test_linktree_directory_link():
    """Test directory link tracking."""
    tree = LinkTree()
    source = Path("/dotfiles/nvim/.config/nvim")
    target = Path("/home/user/.config/nvim")

    tree.add_link(target, source, "nvim", is_dir_link=True)
    assert tree.is_directory_link(target)


def test_linktree_can_fold_single_package():
    """Test can_fold with single package."""
    tree = LinkTree()
    target_dir = Path("/home/user/.config/nvim")

    # Add files from same package
    tree.add_link(target_dir / "init.lua", Path("/dotfiles/nvim/.config/nvim/init.lua"), "nvim")
    tree.add_link(target_dir / "lua" / "config.lua", Path("/dotfiles/nvim/.config/nvim/lua/config.lua"), "nvim")

    # Should be able to fold since all files are from same package
    assert tree.can_fold(target_dir, "nvim")


def test_linktree_can_fold_multiple_packages():
    """Test can_fold with multiple packages."""
    tree = LinkTree()
    target_dir = Path("/home/user/.config")

    # Add files from different packages
    tree.add_link(target_dir / "nvim", Path("/dotfiles/nvim/.config/nvim"), "nvim", is_dir_link=True)
    tree.add_link(target_dir / "tmux", Path("/dotfiles/tmux/.config/tmux"), "tmux", is_dir_link=True)

    # Cannot fold .config since it has files from multiple packages
    assert not tree.can_fold(target_dir, "nvim")


def test_linktree_from_state_old_format_rejected():
    """Old state format should be rejected (no backward compatibility)."""
    state = {
        "links": {
            "zsh": {
                "/home/user/.zshrc": "/dotfiles/zsh/.zshrc",
                "/home/user/.zshenv": "/dotfiles/zsh/.zshenv",
            }
        }
    }

    with pytest.raises(RuntimeError, match="Unsupported linked state format"):
        LinkTree.from_state(state)


def test_linktree_from_state_new_format():
    """Test loading from new state format (with is_directory_link)."""
    state = {
        "version": 2,
        "links": {
            "nvim": {
                "/home/user/.config/nvim": {
                    "source": "/dotfiles/nvim/.config/nvim",
                    "is_directory_link": True,
                }
            }
        }
    }

    tree = LinkTree.from_state(state)
    target = Path("/home/user/.config/nvim")
    assert target in tree.links
    assert tree.is_directory_link(target)
    assert tree.packages[target] == "nvim"


def test_linktree_to_state():
    """Test converting LinkTree to state format."""
    tree = LinkTree()
    tree.add_link(
        Path("/home/user/.config/nvim"),
        Path("/dotfiles/nvim/.config/nvim"),
        "nvim",
        is_dir_link=True,
    )
    tree.add_link(
        Path("/home/user/.zshrc"),
        Path("/dotfiles/zsh/.zshrc"),
        "zsh",
        is_dir_link=False,
    )

    state = tree.to_state()
    assert state["version"] == 2
    assert "nvim" in state["links"]
    assert "zsh" in state["links"]

    nvim_link = state["links"]["nvim"]["/home/user/.config/nvim"]
    assert nvim_link["is_directory_link"] is True

    zsh_link = state["links"]["zsh"]["/home/user/.zshrc"]
    assert zsh_link["is_directory_link"] is False


def test_treefolder_plan_link_simple(temp_home, temp_dotfiles):
    """Test planning a simple file link."""
    tree = LinkTree()
    folder = TreeFolder(tree)

    source = temp_dotfiles / "zsh" / ".zshrc"
    target = temp_home / ".zshrc"

    # Create source file
    source.parent.mkdir(parents=True)
    source.write_text("# zshrc")

    ops = folder.plan_link(source, target, "zsh")
    assert len(ops) == 1
    assert ops[0].type == "create_symlink"
    assert ops[0].source == source
    assert ops[0].target == target
    assert ops[0].package == "zsh"


def test_treefolder_detect_conflicts_existing_file(temp_home, temp_dotfiles):
    """Test conflict detection for existing files."""
    tree = LinkTree()
    folder = TreeFolder(tree)

    source = temp_dotfiles / "zsh" / ".zshrc"
    target = temp_home / ".zshrc"

    # Create existing file
    target.parent.mkdir(parents=True, exist_ok=True)
    target.write_text("# existing")

    source.parent.mkdir(parents=True)
    source.write_text("# zshrc")

    ops = folder.plan_link(source, target, "zsh")
    conflicts = folder.detect_conflicts(ops)

    assert len(conflicts) == 1
    assert "already exists" in conflicts[0]


def test_treefolder_detect_conflicts_different_package(temp_home, temp_dotfiles):
    """Test conflict detection for links from different packages."""
    tree = LinkTree()
    target = temp_home / ".bashrc"

    # Add existing link from different package
    tree.add_link(target, Path("/dotfiles/bash/.bashrc"), "bash")

    folder = TreeFolder(tree)
    source = temp_dotfiles / "zsh" / ".bashrc"
    source.parent.mkdir(parents=True)
    source.write_text("# bashrc")

    ops = folder.plan_link(source, target, "zsh")
    conflicts = folder.detect_conflicts(ops)

    assert len(conflicts) == 1
    assert "bash" in conflicts[0]


def test_treefolder_execute_operations_dry_run(temp_home, temp_dotfiles, capsys):
    """Test dry-run mode."""
    tree = LinkTree()
    folder = TreeFolder(tree)

    source = temp_dotfiles / "zsh" / ".zshrc"
    target = temp_home / ".zshrc"

    source.parent.mkdir(parents=True)
    source.write_text("# zshrc")

    ops = folder.plan_link(source, target, "zsh")
    folder.execute_operations(ops, dry_run=True)

    # Check output
    captured = capsys.readouterr()
    assert "FILE LINK" in captured.out
    assert str(target) in captured.out

    # No actual symlink created
    assert not target.exists()


def test_treefolder_execute_operations_create_symlink(temp_home, temp_dotfiles):
    """Test creating actual symlinks."""
    tree = LinkTree()
    folder = TreeFolder(tree)

    source = temp_dotfiles / "zsh" / ".zshrc"
    target = temp_home / ".zshrc"

    source.parent.mkdir(parents=True)
    source.write_text("# zshrc")

    ops = folder.plan_link(source, target, "zsh")
    folder.execute_operations(ops, dry_run=False)

    # Check symlink created
    assert target.is_symlink()
    assert target.resolve() == source.resolve()

    # Check tree updated
    assert target in folder.tree.links


def test_treefolder_plan_unlink(temp_home, temp_dotfiles):
    """Test planning unlink operations."""
    tree = LinkTree()
    target = temp_home / ".zshrc"
    source = temp_dotfiles / "zsh" / ".zshrc"

    tree.add_link(target, source, "zsh")

    folder = TreeFolder(tree)
    ops = folder.plan_unlink(target, "zsh")

    assert len(ops) == 1
    assert ops[0].type == "remove"
    assert ops[0].target == target


def test_treefolder_plan_unlink_directory_link(temp_home, temp_dotfiles):
    """Test planning unlink for directory symlink."""
    tree = LinkTree()
    target = temp_home / ".config" / "nvim"
    source = temp_dotfiles / "nvim" / ".config" / "nvim"

    tree.add_link(target, source, "nvim", is_dir_link=True)

    folder = TreeFolder(tree)
    ops = folder.plan_unlink(target, "nvim")

    # Should remove the directory link
    assert len(ops) >= 1
    assert ops[-1].type == "remove"
    assert ops[-1].is_directory_link


def test_linkoperation_str():
    """Test LinkOperation string representation."""
    op1 = LinkOperation(
        type="create_symlink",
        source=Path("/src"),
        target=Path("/dst"),
        package="test",
        is_directory_link=False,
    )
    assert "FILE LINK" in str(op1)

    op2 = LinkOperation(
        type="create_symlink",
        source=Path("/src"),
        target=Path("/dst"),
        package="test",
        is_directory_link=True,
    )
    assert "DIR LINK" in str(op2)

    op3 = LinkOperation(
        type="unfold",
        source=Path("/src"),
        target=Path("/dst"),
        package="test",
    )
    assert "UNFOLD" in str(op3)