"""Export functionality for detected patterns."""

from datetime import datetime
from pathlib import Path
from typing import Optional

from shellhist.core import HistoryStore
from shellhist.core.patterns import CommandPattern


def generate_script(
    patterns: list[CommandPattern],
    script_name: str = "shellhist_script",
    output_dir: Optional[str] = None,
    dry_run: bool = False,
) -> str:
    """Generate a shell script from detected patterns.
    
    Args:
        patterns: List of CommandPattern objects to export.
        script_name: Name for the output script (without extension).
        output_dir: Optional output directory. If not provided, uses current directory.
        dry_run: If True, return script content without writing to file.
        
    Returns:
        Path to the generated script or script content if dry_run.
    """
    script_content = _build_script_content(patterns, script_name)
    
    if dry_run:
        return script_content
    
    output_path = Path(output_dir) if output_dir else Path.cwd()
    output_path.mkdir(parents=True, exist_ok=True)
    
    script_file = output_path / f"{script_name}.sh"
    script_file.write_text(script_content, encoding="utf-8")
    
    return str(script_file)


def _build_script_content(patterns: list[CommandPattern], script_name: str) -> str:
    """Build the content of the generated shell script."""
    lines = [
        f"#!/bin/bash",
        f"# Generated by Shell History Automation Tool",
        f"# Date: {datetime.now().strftime('%Y-%m-%d %H:%M:%S')}",
        "",
        f"# {script_name} - Automated shell script from detected patterns",
        "",
    ]
    
    for i, pattern in enumerate(patterns, 1):
        if len(pattern.commands) == 1:
            cmd = pattern.commands[0]
            lines.append(f"# Pattern {i}: Command run {pattern.frequency} times")
            lines.append(f"{cmd}")
        else:
            cmds = " && ".join(pattern.commands)
            lines.append(f"# Pattern {i}: Sequence run {pattern.frequency} times")
            lines.append(f"{cmds}")
        lines.append("")
    
    lines.extend([
        "# End of generated script",
        "echo 'Script execution completed.'",
    ])
    
    return "\n".join(lines)