"""
Core functionality for repo-to-text
"""

import os
import subprocess
from typing import Tuple, Optional, List, Dict, Any, Set
from datetime import datetime, timezone
import logging
import yaml
import pathspec
from pathspec import PathSpec

from ..utils.utils import check_tree_command, is_ignored_path

def get_tree_structure(
        path: str = '.',
        gitignore_spec: Optional[PathSpec] = None,
        tree_and_content_ignore_spec: Optional[PathSpec] = None
    ) -> str:
    """Generate tree structure of the directory.
    
    Args:
        path: Directory path to generate tree for
        gitignore_spec: PathSpec object for gitignore patterns
        tree_and_content_ignore_spec: PathSpec object for tree and content ignore patterns
        
    Returns:
        str: Generated tree structure with empty directories and ignored files removed
    """
    if not check_tree_command():
        return ""

    logging.debug('Generating tree structure for path: %s', path)
    result = subprocess.run(
        ['tree', '-a', '-f', '--noreport', path],
        stdout=subprocess.PIPE,
        check=True
    )
    tree_output = result.stdout.decode('utf-8')
    logging.debug('Tree output generated:\n%s', tree_output)

    if not gitignore_spec and not tree_and_content_ignore_spec:
        logging.debug('No .gitignore or ignore-tree-and-content specification found')
        return tree_output

    logging.debug(
        'Filtering tree output based on .gitignore and ignore-tree-and-content specification'
    )
    lines: List[str] = tree_output.splitlines()
    non_empty_dirs: Set[str] = set()
    current_path: List[str] = []

    for line in lines:
        indent_level = len(line) - len(line.lstrip('│ ├└'))
        current_path = current_path[:indent_level]

        idx = line.find('./')
        if idx == -1:
            idx = line.find(path)
        if idx != -1:
            full_path = line[idx:].strip()
        else:
            continue

        if full_path == '.':
            continue

        relative_path = os.path.relpath(full_path, path)
        relative_path = relative_path.replace(os.sep, '/')

        # Skip if file should be ignored
        if should_ignore_file(
            full_path,
            relative_path,
            gitignore_spec,
            None,
            tree_and_content_ignore_spec
        ):
            logging.debug('Ignored: %s', relative_path)
            continue

        # If this is a file, mark all parent directories as non-empty
        if not os.path.isdir(full_path):
            dir_path = os.path.dirname(relative_path)
            while dir_path:
                non_empty_dirs.add(dir_path)
                dir_path = os.path.dirname(dir_path)

    # Second pass: build filtered output
    filtered_lines: List[str] = []
    current_path = []

    for line in lines:
        indent_level = len(line) - len(line.lstrip('│ ├└'))
        current_path = current_path[:indent_level]

        # Always include root path
        if indent_level == 0:
            filtered_lines.append(line)
            continue

        idx = line.find('./')
        if idx == -1:
            idx = line.find(path)
        if idx != -1:
            full_path = line[idx:].strip()
        else:
            continue

        relative_path = os.path.relpath(full_path, path)
        relative_path = relative_path.replace(os.sep, '/')

        # Skip if file should be ignored
        if should_ignore_file(
            full_path,
            relative_path,
            gitignore_spec,
            None,
            tree_and_content_ignore_spec
        ):
            continue

        # Include line if it's a file or a non-empty directory
        if not os.path.isdir(full_path) or os.path.dirname(relative_path) in non_empty_dirs:
            display_line = line.replace('./', '', 1)
            filtered_lines.append(display_line)

    filtered_tree_output = '\n'.join(filtered_lines)
    logging.debug('Filtered tree structure:\n%s', filtered_tree_output)
    return filtered_tree_output

def load_ignore_specs(
        path: str = '.',
        cli_ignore_patterns: Optional[List[str]] = None
    ) -> Tuple[Optional[PathSpec], Optional[PathSpec], PathSpec]:
    """Load ignore specifications from various sources.
    
    Args:
        path: Base directory path
        cli_ignore_patterns: List of patterns from command line
        
    Returns:
        Tuple[Optional[PathSpec], Optional[PathSpec], PathSpec]: Tuple of gitignore_spec, 
        content_ignore_spec, and tree_and_content_ignore_spec
    """
    gitignore_spec = None
    content_ignore_spec = None
    tree_and_content_ignore_list: List[str] = []
    use_gitignore = True

    repo_settings_path = os.path.join(path, '.repo-to-text-settings.yaml')
    if os.path.exists(repo_settings_path):
        logging.debug('Loading .repo-to-text-settings.yaml from path: %s', repo_settings_path)
        with open(repo_settings_path, 'r', encoding='utf-8') as f:
            settings: Dict[str, Any] = yaml.safe_load(f)
            use_gitignore = settings.get('gitignore-import-and-ignore', True)
            if 'ignore-content' in settings:
                content_ignore_spec: Optional[PathSpec] = pathspec.PathSpec.from_lines(
                    'gitwildmatch', settings['ignore-content']
                )
            if 'ignore-tree-and-content' in settings:
                tree_and_content_ignore_list.extend(settings.get('ignore-tree-and-content', []))

    if cli_ignore_patterns:
        tree_and_content_ignore_list.extend(cli_ignore_patterns)

    if use_gitignore:
        gitignore_path = os.path.join(path, '.gitignore')
        if os.path.exists(gitignore_path):
            logging.debug('Loading .gitignore from path: %s', gitignore_path)
            with open(gitignore_path, 'r', encoding='utf-8') as f:
                gitignore_spec = pathspec.PathSpec.from_lines('gitwildmatch', f)

    tree_and_content_ignore_spec = pathspec.PathSpec.from_lines(
        'gitwildmatch', tree_and_content_ignore_list
    )
    return gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec

def should_ignore_file(
    file_path: str,
    relative_path: str,
    gitignore_spec: Optional[PathSpec],
    content_ignore_spec: Optional[PathSpec],
    tree_and_content_ignore_spec: Optional[PathSpec]
) -> bool:
    """Check if a file should be ignored based on various ignore specifications.
    
    Args:
        file_path: Full path to the file
        relative_path: Path relative to the repository root
        gitignore_spec: PathSpec object for gitignore patterns
        content_ignore_spec: PathSpec object for content ignore patterns
        tree_and_content_ignore_spec: PathSpec object for tree and content ignore patterns
        
    Returns:
        bool: True if file should be ignored, False otherwise
    """
    relative_path = relative_path.replace(os.sep, '/')

    if relative_path.startswith('./'):
        relative_path = relative_path[2:]

    if os.path.isdir(file_path):
        relative_path += '/'

    result = (
        is_ignored_path(file_path) or
        bool(
            gitignore_spec and
            gitignore_spec.match_file(relative_path)
        ) or
        bool(
            content_ignore_spec and
            content_ignore_spec.match_file(relative_path)
        ) or
        bool(
            tree_and_content_ignore_spec and
            tree_and_content_ignore_spec.match_file(relative_path)
        ) or
        os.path.basename(file_path).startswith('repo-to-text_')
    )

    logging.debug('Checking if file should be ignored:')
    logging.debug('    file_path: %s', file_path)
    logging.debug('    relative_path: %s', relative_path)
    logging.debug('    Result: %s', result)
    return result

def save_repo_to_text(
        path: str = '.',
        output_dir: Optional[str] = None,
        to_stdout: bool = False,
        cli_ignore_patterns: Optional[List[str]] = None
    ) -> str:
    """Save repository structure and contents to a text file.
    
    Args:
        path: Repository path
        output_dir: Directory to save output file
        to_stdout: Whether to output to stdout instead of file
        cli_ignore_patterns: List of patterns from command line
        
    Returns:
        str: Path to the output file or the output text if to_stdout is True
    """
    logging.debug('Starting to save repo structure to text for path: %s', path)
    gitignore_spec, content_ignore_spec, tree_and_content_ignore_spec = load_ignore_specs(
        path, cli_ignore_patterns
    )
    tree_structure: str = get_tree_structure(
        path, gitignore_spec, tree_and_content_ignore_spec
    )
    logging.debug('Final tree structure to be written: %s', tree_structure)

    timestamp = datetime.now(timezone.utc).strftime('%Y-%m-%d-%H-%M-%S-UTC')
    output_file = f'repo-to-text_{timestamp}.txt'

    if output_dir:
        if not os.path.exists(output_dir):
            os.makedirs(output_dir)
        output_file = os.path.join(output_dir, output_file)

    output_content: List[str] = []
    project_name = os.path.basename(os.path.abspath(path))
    output_content.append(f'Directory: {project_name}\n\n')
    output_content.append('Directory Structure:\n')
    output_content.append('```\n.\n')

    if os.path.exists(os.path.join(path, '.gitignore')):
        output_content.append('├── .gitignore\n')

    output_content.append(tree_structure + '\n' + '```\n')
    logging.debug('Tree structure written to output content')

    for root, _, files in os.walk(path):
        for filename in files:
            file_path = os.path.join(root, filename)
            relative_path = os.path.relpath(file_path, path)

            if should_ignore_file(
                file_path,
                relative_path,
                gitignore_spec,
                content_ignore_spec,
                tree_and_content_ignore_spec
            ):
                continue

            relative_path = relative_path.replace('./', '', 1)

            output_content.append(f'\nContents of {relative_path}:\n')
            output_content.append('```\n')
            try:
                with open(file_path, 'r', encoding='utf-8') as f:
                    output_content.append(f.read())
            except UnicodeDecodeError:
                logging.debug('Could not decode file contents: %s', file_path)
                output_content.append('[Could not decode file contents]\n')
            output_content.append('\n```\n')

    output_content.append('\n')
    logging.debug('Repository contents written to output content')

    output_text = ''.join(output_content)

    if to_stdout:
        print(output_text)
        return output_text

    with open(output_file, 'w', encoding='utf-8') as file:
        file.write(output_text)

    try:
        import importlib.util # pylint: disable=import-outside-toplevel
        if importlib.util.find_spec("pyperclip"):
            import pyperclip # pylint: disable=import-outside-toplevel # type: ignore
            pyperclip.copy(output_text) # type: ignore
            logging.debug('Repository structure and contents copied to clipboard')
        else:
            print("Tip: Install 'pyperclip' package to enable automatic clipboard copying:")
            print("     pip install pyperclip")
    except (ImportError) as e:
        logging.warning(
            'Could not copy to clipboard. You might be running this '
            'script over SSH or without clipboard support.'
        )
        logging.debug('Clipboard copy error: %s', e)

    print(
        "[SUCCESS] Repository structure and contents successfully saved to "
        f"file: \"./{output_file}\""
    )

    return output_file