import difflib
import os
import subprocess
import tempfile

from ..ui.diff_display import display_diff, get_diff_stats


def apply_patch(filepath, patch_content, db_conn=None):
    """Apply a patch to a file.

    Args:
        filepath: Path to the file to patch.
        patch_content: The patch content as a string.
        db_conn: Database connection (optional).

    Returns:
        Dict with status and output.
    """
    try:
        path = os.path.expanduser(filepath)
        if db_conn:
            from pr.tools.database import db_get

            read_status = db_get("read:" + path, db_conn)
            if read_status.get("status") != "success" or read_status.get("value") != "true":
                return {
                    "status": "error",
                    "error": "File must be read before writing. Please read the file first.",
                }
        # Write patch to temp file
        with tempfile.NamedTemporaryFile(mode="w", delete=False, suffix=".patch") as f:
            f.write(patch_content)
            patch_file = f.name
        # Run patch command
        result = subprocess.run(
            ["patch", path, patch_file],
            capture_output=True,
            text=True,
            cwd=os.path.dirname(path),
        )
        os.unlink(patch_file)
        if result.returncode == 0:
            return {"status": "success", "output": result.stdout.strip()}
        else:
            return {"status": "error", "error": result.stderr.strip()}
    except Exception as e:
        return {"status": "error", "error": str(e)}


def create_diff(
    file1, file2, fromfile="file1", tofile="file2", visual=False, format_type="unified"
):
    """Create a unified diff between two files.

    Args:
        file1: Path to the first file.
        file2: Path to the second file.
        fromfile: Label for the first file.
        tofile: Label for the second file.
        visual: Whether to include visual diff.
        format_type: Diff format type.

    Returns:
        Dict with status and diff content.
    """
    try:
        path1 = os.path.expanduser(file1)
        path2 = os.path.expanduser(file2)
        with open(path1) as f1, open(path2) as f2:
            content1 = f1.read()
            content2 = f2.read()

        if visual:
            visual_diff = display_diff(content1, content2, fromfile, format_type)
            stats = get_diff_stats(content1, content2)
            lines1 = content1.splitlines(keepends=True)
            lines2 = content2.splitlines(keepends=True)
            plain_diff = list(
                difflib.unified_diff(lines1, lines2, fromfile=fromfile, tofile=tofile)
            )
            return {
                "status": "success",
                "diff": "".join(plain_diff),
                "visual_diff": visual_diff,
                "stats": stats,
            }
        else:
            lines1 = content1.splitlines(keepends=True)
            lines2 = content2.splitlines(keepends=True)
            diff = list(difflib.unified_diff(lines1, lines2, fromfile=fromfile, tofile=tofile))
            return {"status": "success", "diff": "".join(diff)}
    except Exception as e:
        return {"status": "error", "error": str(e)}


def display_file_diff(filepath1, filepath2, format_type="unified", context_lines=3):
    try:
        path1 = os.path.expanduser(filepath1)
        path2 = os.path.expanduser(filepath2)

        with open(path1) as f1:
            old_content = f1.read()
        with open(path2) as f2:
            new_content = f2.read()

        visual_diff = display_diff(old_content, new_content, filepath1, format_type)
        stats = get_diff_stats(old_content, new_content)

        return {"status": "success", "visual_diff": visual_diff, "stats": stats}
    except Exception as e:
        return {"status": "error", "error": str(e)}


def display_content_diff(old_content, new_content, filename="file", format_type="unified"):
    try:
        visual_diff = display_diff(old_content, new_content, filename, format_type)
        stats = get_diff_stats(old_content, new_content)

        return {"status": "success", "visual_diff": visual_diff, "stats": stats}
    except Exception as e:
        return {"status": "error", "error": str(e)}