# http_client.py
#
# Copyright 2025 Pavel Baksy
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
# SPDX-License-Identifier: GPL-3.0-or-later

import subprocess
import time
from typing import Tuple, Optional
from .models import HttpRequest, HttpResponse


class HttpClient:
    """HTTP client using HTTPie as backend."""

    def execute_request(self, request: HttpRequest) -> Tuple[Optional[HttpResponse], Optional[str]]:
        """
        Execute HTTP request using HTTPie.

        Args:
            request: HttpRequest object with method, url, headers, body

        Returns:
            Tuple of (response, error_message)
            If successful: (HttpResponse, None)
            If failed: (None, error_message)
        """
        # Build command
        cmd = ['http', '--print=HhBb', request.method, request.url]

        # Add headers
        for key, value in request.headers.items():
            if key and value:  # Skip empty headers
                cmd.append(f'{key}:{value}')

        # Prepare stdin for body (if POST/PUT/DELETE and body exists)
        stdin_data = None
        if request.method in ['POST', 'PUT', 'DELETE'] and request.body.strip():
            stdin_data = request.body.encode('utf-8')
        else:
            # Only use --ignore-stdin when there's no body
            cmd.insert(2, '--ignore-stdin')

        # Execute with timing
        start_time = time.time()
        try:
            result = subprocess.run(
                cmd,
                input=stdin_data,
                capture_output=True,
                timeout=30,  # 30 second timeout
                text=False  # We'll decode manually
            )
            end_time = time.time()
            response_time = (end_time - start_time) * 1000  # Convert to ms

            # Parse output
            output = result.stdout.decode('utf-8', errors='replace')

            if result.returncode != 0:
                error_msg = result.stderr.decode('utf-8', errors='replace')
                return None, error_msg

            # Parse HTTPie output
            response = self._parse_httpie_output(output, response_time)
            return response, None

        except subprocess.TimeoutExpired:
            return None, "Request timeout (30 seconds)"
        except FileNotFoundError:
            return None, "HTTPie not installed. Please install with: pip install httpie"
        except Exception as e:
            return None, f"Error: {str(e)}"

    def _parse_httpie_output(self, output: str, response_time: float) -> HttpResponse:
        """
        Parse HTTPie --print=HhBb output format.

        Format:
        REQUEST HEADERS
        <blank line>
        REQUEST BODY
        <blank line>
        <blank line>
        RESPONSE HEADERS (starts with HTTP/1.1 200 OK)
        <blank line>
        RESPONSE BODY
        """
        # Split output into lines to manually find response section
        lines = output.split('\n')

        # Find where response headers start (line starting with HTTP/)
        response_header_start = 0
        for i, line in enumerate(lines):
            if line.startswith('HTTP/'):
                response_header_start = i
                break

        # Parse status line
        status_line = lines[response_header_start]
        parts = status_line.split(' ', 2)

        if len(parts) < 2:
            raise ValueError(f"Invalid status line: {status_line}")

        status_code = int(parts[1])
        status_text = parts[2] if len(parts) > 2 else ''

        # Find where response headers end (first empty line after response starts)
        response_body_start = response_header_start + 1
        for i in range(response_header_start + 1, len(lines)):
            if lines[i].strip() == '':
                response_body_start = i + 1
                break

        # Extract response headers (from HTTP/ line to first blank line)
        response_headers = '\n'.join(lines[response_header_start:response_body_start - 1])

        # Extract response body (everything after the blank line)
        response_body = '\n'.join(lines[response_body_start:])

        return HttpResponse(
            status_code=status_code,
            status_text=status_text,
            headers=response_headers,
            body=response_body.strip(),
            response_time_ms=response_time
        )