#!/usr/bin/env python3
from __future__ import annotations

import argparse
import json
import os
import re
import sys
import time
import urllib.error
import urllib.parse
import urllib.request
from pathlib import Path
from typing import Any

OPENHANDS_BASE_URL = os.environ.get('OPENHANDS_BASE_URL', 'https://app.all-hands.dev')
REPOSITORY_PATTERN = re.compile(r'^[a-zA-Z0-9_.-]+/[a-zA-Z0-9_.-]+$')
GITHUB_API_BASE_URL = os.environ.get('GITHUB_API_BASE_URL', 'https://api.github.com')
FAILED_EXECUTION_STATUSES = {
    'error',
    'errored',
    'failed',
    'stopped',
}
SUCCESSFUL_TERMINAL_EXECUTION_STATUSES = {
    'completed',
    'finished',
}
TERMINAL_EXECUTION_STATUSES = (
    FAILED_EXECUTION_STATUSES | SUCCESSFUL_TERMINAL_EXECUTION_STATUSES
)
EVENT_SEARCH_LIMIT = 1000
EVENT_SEARCH_LIMIT_HIT_MESSAGE = (
    f'Event search returned at least {EVENT_SEARCH_LIMIT} events; results may be '
    'incomplete'
)


def parse_args() -> argparse.Namespace:
    parser = argparse.ArgumentParser(
        description=(
            'Start an OpenHands Cloud conversation that checks a GitHub issue '
            'for duplicates.'
        )
    )
    parser.add_argument(
        '--repository', required=True, help='Repository in owner/repo form'
    )
    parser.add_argument(
        '--issue-number', required=True, type=int, help='Issue number to inspect'
    )
    parser.add_argument(
        '--output',
        default='duplicate-check-result.json',
        help='Path where the JSON result should be written',
    )
    parser.add_argument(
        '--poll-interval-seconds',
        default=5,
        type=int,
        help='Polling interval while waiting for the conversation to finish',
    )
    parser.add_argument(
        '--max-wait-seconds',
        default=900,
        type=int,
        help=(
            'Maximum time to wait per polling phase; if a start task must be awaited '
            'first, the total runtime can approach twice this value'
        ),
    )
    return parser.parse_args()


def github_headers() -> dict[str, str]:
    headers = {
        'Accept': 'application/vnd.github+json',
        'User-Agent': 'openhands-issue-duplicate-check',
        'X-GitHub-Api-Version': '2022-11-28',
    }
    github_token = os.environ.get('GITHUB_TOKEN')
    if github_token:
        headers['Authorization'] = f'Bearer {github_token}'
    return headers


def openhands_headers() -> dict[str, str]:
    api_key = os.environ.get('OPENHANDS_API_KEY')
    if not api_key:
        raise RuntimeError('OPENHANDS_API_KEY environment variable is required')
    return {
        'Authorization': f'Bearer {api_key}',
        'Content-Type': 'application/json',
    }


def request_json(
    base_url: str,
    path: str,
    *,
    method: str = 'GET',
    headers: dict[str, str] | None = None,
    body: dict[str, Any] | None = None,
) -> Any:
    data = json.dumps(body).encode('utf-8') if body is not None else None
    request = urllib.request.Request(
        f'{base_url}{path}',
        data=data,
        headers=headers or {},
        method=method,
    )
    try:
        with urllib.request.urlopen(request, timeout=60) as response:
            return json.load(response)
    except urllib.error.HTTPError as exc:
        error_body = exc.read().decode('utf-8', errors='replace')
        raise RuntimeError(
            f'{method} {base_url}{path} failed with HTTP {exc.code}: {error_body}'
        ) from exc
    except json.JSONDecodeError as exc:
        raise RuntimeError(
            f'Failed to parse JSON from {method} {base_url}{path}: {exc}'
        ) from exc
    except urllib.error.URLError as exc:
        raise RuntimeError(f'{method} {base_url}{path} failed: {exc}') from exc


def fetch_issue(repository: str, issue_number: int) -> dict[str, Any]:
    if not REPOSITORY_PATTERN.fullmatch(repository):
        raise ValueError(f'Invalid repository format: {repository}')
    return request_json(
        GITHUB_API_BASE_URL,
        f'/repos/{repository}/issues/{issue_number}',
        headers=github_headers(),
    )


def escape_json_text(value: str | None) -> str:
    return json.dumps(value or '', ensure_ascii=False)


def build_prompt(repository: str, issue: dict[str, Any]) -> str:
    issue_number = issue['number']
    issue_title = issue.get('title', '')
    issue_body = issue.get('body') or ''
    issue_url = issue.get('html_url', '')
    issue_title_json = escape_json_text(issue_title)
    issue_body_json = escape_json_text(issue_body)

    return '\n'.join(
        [
            'You are investigating whether a GitHub issue should be redirected '
            'to an existing issue because it is either:',
            '- an exact or near-exact duplicate, or',
            '- so overlapping in scope that discussion or fix planning would '
            'likely be better kept in one canonical issue.',
            '',
            'Be conservative about auto-close decisions, but do investigate '
            'seriously before deciding.',
            '',
            f'Repository: {repository}',
            f'New issue number: #{issue_number}',
            f'New issue URL: {issue_url}',
            f'New issue title (JSON-escaped string): {issue_title_json}',
            f'New issue body (JSON-escaped string): {issue_body_json}',
            '',
            'Task:',
            '1. Understand the core problem, user-facing outcome, likely root '
            'cause, and requested fix or behavior.',
            "2. Investigate this repository's open issues and issues closed "
            'in the last 90 days for exact duplicates, near-duplicates, or '
            'strong scope overlap.',
            '3. Use multiple search approaches with diverse keywords and '
            'phrasings rather than a single literal search.',
            '4. Ignore pull requests.',
            '5. Distinguish carefully between:',
            '   - duplicate: essentially the same report, request, or root cause',
            '   - overlapping-scope: not identical, but likely to fragment '
            'discussion or produce competing fixes',
            '   - related-but-distinct: similar area, but should stay separate',
            '   - no-match: no strong candidate worth redirecting to',
            '6. Inspect the strongest 1-3 candidates carefully. If needed, '
            'inspect comments on the strongest candidates to disambiguate '
            'false positives.',
            '7. Do not post comments, do not modify files, and do not change '
            'repository state.',
            '8. Useful API shapes include:',
            f'   - GET https://api.github.com/repos/{repository}/issues?state=open&per_page=100',
            '   - GET https://api.github.com/repos/'
            f'{repository}/issues?state=closed&since=<ISO-8601 timestamp>&per_page=100',
            '   - GET https://api.github.com/search/issues?q=<query>',
            f'   - GET https://api.github.com/repos/{repository}/issues/<number>/comments',
            '9. Return exactly one JSON object and nothing else. Do not wrap '
            'it in markdown fences.',
            '',
            'Return schema:',
            '{',
            f'  "issue_number": {issue_number},',
            '  "should_comment": true or false,',
            '  "is_duplicate": true or false,',
            '  "auto_close_candidate": true or false,',
            '  "classification": "duplicate" | "overlapping-scope" | '
            '"related-but-distinct" | "no-match",',
            '  "confidence": "high" | "medium" | "low",',
            '  "summary": "short explanation",',
            '  "canonical_issue_number": 123 or null,',
            '  "candidate_issues": [',
            '    {',
            '      "number": 123,',
            f'      "url": "https://github.com/{repository}/issues/123",',
            '      "title": "issue title",',
            '      "state": "open or closed",',
            '      "closed_at": "ISO timestamp or null",',
            '      "similarity_reason": "why it looks similar"',
            '    }',
            '  ]',
            '}',
            '',
            'Rules:',
            '- `should_comment` should be true only when redirecting the '
            'author would likely help.',
            '- `is_duplicate` should be true only for exact or near-exact duplicates.',
            '- `auto_close_candidate` should be true only when:',
            '  - classification is `duplicate`',
            '  - confidence is `high`',
            '  - one canonical issue clearly stands out',
            '  - a maintainer would likely be comfortable closing this issue '
            'after a waiting period',
            '- For `overlapping-scope`, `auto_close_candidate` must be false.',
            '- `candidate_issues` must contain at most 3 issues, sorted best-first.',
            '- If no strong match exists, return `should_comment: false`, '
            '`classification: "no-match"`, `canonical_issue_number: null`, '
            'and an empty candidate list.',
            '- Be especially careful not to collapse broad meta, tracking, '
            'feedback, or umbrella issues with specific bug reports unless '
            'the new issue clearly belongs in that exact thread.',
        ]
    )


def start_conversation(
    prompt: str, repository: str, issue_number: int
) -> dict[str, Any]:
    body = {
        'title': f'Issue duplicate check #{issue_number}',
        'selected_repository': repository,
        'initial_message': {
            'content': [
                {
                    'type': 'text',
                    'text': prompt,
                }
            ]
        },
    }
    return request_json(
        OPENHANDS_BASE_URL,
        '/api/v1/app-conversations',
        method='POST',
        headers=openhands_headers(),
        body=body,
    )


def extract_first_item(payload: Any) -> dict[str, Any] | None:
    if isinstance(payload, list):
        first_item = payload[0] if payload else None
        return first_item if isinstance(first_item, dict) else None
    if not isinstance(payload, dict):
        return None

    items = payload.get('items')
    if isinstance(items, list):
        first_item = items[0] if items else None
        return first_item if isinstance(first_item, dict) else None
    return payload


def poll_start_task(
    start_task_id: str, poll_interval_seconds: int, max_wait_seconds: int
) -> dict[str, Any]:
    deadline = time.time() + max_wait_seconds
    while time.time() < deadline:
        payload = request_json(
            OPENHANDS_BASE_URL,
            f'/api/v1/app-conversations/start-tasks?ids={urllib.parse.quote(start_task_id)}',
            headers={'Authorization': openhands_headers()['Authorization']},
        )
        item = extract_first_item(payload)
        if item is None:
            time.sleep(poll_interval_seconds)
            continue
        status = item.get('status')
        if status == 'READY' and item.get('app_conversation_id'):
            return item
        if status in {'ERROR', 'FAILED'}:
            raise RuntimeError(f'OpenHands start task failed: {json.dumps(item)}')
        time.sleep(poll_interval_seconds)
    raise TimeoutError(
        f'Timed out waiting for start task {start_task_id} to become ready'
    )


def poll_conversation(
    app_conversation_id: str, poll_interval_seconds: int, max_wait_seconds: int
) -> dict[str, Any]:
    deadline = time.time() + max_wait_seconds
    while time.time() < deadline:
        payload = request_json(
            OPENHANDS_BASE_URL,
            f'/api/v1/app-conversations?ids={urllib.parse.quote(app_conversation_id)}',
            headers={'Authorization': openhands_headers()['Authorization']},
        )
        item = extract_first_item(payload)
        if item is None:
            time.sleep(poll_interval_seconds)
            continue
        execution_status = str(item.get('execution_status', '')).lower()
        if execution_status in FAILED_EXECUTION_STATUSES:
            raise RuntimeError(
                'OpenHands conversation ended with '
                f'{execution_status}: {json.dumps(item)}'
            )
        if execution_status in SUCCESSFUL_TERMINAL_EXECUTION_STATUSES:
            return item
        time.sleep(poll_interval_seconds)
    raise TimeoutError(
        f'Timed out waiting for conversation {app_conversation_id} to finish running'
    )


def validate_event_search_results(events: list[dict[str, Any]]) -> list[dict[str, Any]]:
    if len(events) >= EVENT_SEARCH_LIMIT:
        raise RuntimeError(EVENT_SEARCH_LIMIT_HIT_MESSAGE)
    return events


def fetch_app_server_events(app_conversation_id: str) -> list[dict[str, Any]]:
    payload = request_json(
        OPENHANDS_BASE_URL,
        f'/api/v1/conversation/{urllib.parse.quote(app_conversation_id)}/events/search?limit={EVENT_SEARCH_LIMIT}',
        headers={'Authorization': openhands_headers()['Authorization']},
    )
    if isinstance(payload, dict):
        items = payload.get('items')
        return validate_event_search_results(items) if isinstance(items, list) else []
    if isinstance(payload, list):
        return validate_event_search_results(payload)
    return []


def fetch_agent_server_events(
    app_conversation_id: str, agent_server_url: str, session_api_key: str
) -> list[dict[str, Any]]:
    payload = request_json(
        agent_server_url,
        f'/api/conversations/{urllib.parse.quote(app_conversation_id)}/events/search?limit={EVENT_SEARCH_LIMIT}',
        headers={'X-Session-API-Key': session_api_key},
    )
    if isinstance(payload, dict):
        items = payload.get('items')
        return validate_event_search_results(items) if isinstance(items, list) else []
    if isinstance(payload, list):
        return validate_event_search_results(payload)
    return []


def fetch_agent_server_final_response(
    app_conversation_id: str, agent_server_url: str, session_api_key: str
) -> str:
    payload = request_json(
        agent_server_url,
        f'/api/conversations/{urllib.parse.quote(app_conversation_id)}/agent_final_response',
        headers={'X-Session-API-Key': session_api_key},
    )
    if not isinstance(payload, dict):
        return ''
    return str(payload.get('response') or '').strip()


def extract_agent_server_url(conversation_url: str) -> str | None:
    marker = '/api/conversations/'
    if marker not in conversation_url:
        return None
    return conversation_url.rsplit(marker, 1)[0]


def extract_last_agent_text(events: list[dict[str, Any]]) -> str:
    agent_events = [
        event
        for event in events
        if event.get('kind') == 'MessageEvent' and event.get('source') == 'agent'
    ]
    if not agent_events:
        raise RuntimeError(
            'No assistant text message was found in the conversation events'
        )

    llm_message = agent_events[-1].get('llm_message')
    if not isinstance(llm_message, dict):
        raise RuntimeError('Last agent message has no llm_message field')
    content = llm_message.get('content')
    if not isinstance(content, list):
        raise RuntimeError('Last agent message content is not a list')

    text_parts: list[str] = []
    for part in content:
        if not isinstance(part, dict):
            continue
        if part.get('type') == 'text' and part.get('text'):
            text_parts.append(str(part['text']))
    if not text_parts:
        raise RuntimeError('Last agent message contains no text content')
    return ''.join(text_parts).strip()


def parse_agent_json(text: str) -> dict[str, Any]:
    cleaned = text.strip()
    try:
        return json.loads(cleaned)
    except json.JSONDecodeError:
        decoder = json.JSONDecoder()
        for start, character in enumerate(cleaned):
            if character != '{':
                continue
            try:
                candidate, end = decoder.raw_decode(cleaned[start:])
            except json.JSONDecodeError:
                continue
            trailing = cleaned[start + end :].strip()
            if trailing not in {'', '```'}:
                continue
            if isinstance(candidate, dict):
                return candidate
        raise ValueError('No valid JSON object found in the agent response')


def as_bool(value: Any) -> bool:
    if isinstance(value, bool):
        return value
    if isinstance(value, str):
        return value.strip().lower() in {'true', '1', 'yes'}
    if isinstance(value, (int, float)):
        return bool(value)
    return False


def normalize_result(result: dict[str, Any]) -> dict[str, Any]:
    normalized = dict(result)
    normalized['should_comment'] = as_bool(normalized.get('should_comment'))
    normalized['is_duplicate'] = as_bool(normalized.get('is_duplicate'))
    normalized['auto_close_candidate'] = as_bool(normalized.get('auto_close_candidate'))

    classification = str(normalized.get('classification') or 'no-match').strip().lower()
    if classification not in {
        'duplicate',
        'overlapping-scope',
        'related-but-distinct',
        'no-match',
    }:
        classification = 'no-match'
    normalized['classification'] = classification

    confidence = str(normalized.get('confidence') or 'low').strip().lower()
    if confidence not in {'high', 'medium', 'low'}:
        confidence = 'low'
    normalized['confidence'] = confidence

    try:
        canonical_issue_number = normalized.get('canonical_issue_number')
        if canonical_issue_number in {None, ''}:
            normalized['canonical_issue_number'] = None
        else:
            normalized['canonical_issue_number'] = int(str(canonical_issue_number))
    except (TypeError, ValueError):
        normalized['canonical_issue_number'] = None

    candidate_issues = normalized.get('candidate_issues')
    if not isinstance(candidate_issues, list):
        candidate_issues = []
    normalized['candidate_issues'] = candidate_issues[:3]

    if classification not in {'duplicate', 'overlapping-scope'}:
        normalized['should_comment'] = False
    if classification != 'duplicate':
        normalized['is_duplicate'] = False
        normalized['auto_close_candidate'] = False
    if (
        classification in {'duplicate', 'overlapping-scope'}
        and normalized['candidate_issues']
        and confidence in {'high', 'medium'}
    ):
        normalized['should_comment'] = True
    if normalized['auto_close_candidate'] and confidence != 'high':
        normalized['auto_close_candidate'] = False
    if normalized['auto_close_candidate'] and not normalized['candidate_issues']:
        normalized['auto_close_candidate'] = False
    if (
        normalized['auto_close_candidate']
        and normalized['canonical_issue_number'] is None
    ):
        first_candidate = (
            normalized['candidate_issues'][0] if normalized['candidate_issues'] else {}
        )
        candidate_number = first_candidate.get('number')
        try:
            if candidate_number is None:
                raise ValueError('candidate number is missing')
            normalized['canonical_issue_number'] = int(str(candidate_number))
        except (TypeError, ValueError, AttributeError):
            normalized['auto_close_candidate'] = False

    normalized['summary'] = str(normalized.get('summary') or '').strip()
    return normalized


def main() -> int:
    args = parse_args()
    issue = fetch_issue(args.repository, args.issue_number)
    if issue.get('pull_request'):
        raise RuntimeError(f'#{args.issue_number} is a pull request, not an issue')

    prompt = build_prompt(args.repository, issue)
    start_task = start_conversation(prompt, args.repository, args.issue_number)
    app_conversation_id = start_task.get('app_conversation_id')
    conversation_url = ''

    if not app_conversation_id:
        task_id = start_task.get('id')
        if not task_id:
            raise RuntimeError(f'Missing id in start task response: {start_task}')
        ready_task = poll_start_task(
            task_id,
            args.poll_interval_seconds,
            args.max_wait_seconds,
        )
        app_conversation_id = ready_task.get('app_conversation_id')
        if not app_conversation_id:
            raise RuntimeError(f'Missing app_conversation_id in response: {ready_task}')

    conversation = poll_conversation(
        app_conversation_id,
        args.poll_interval_seconds,
        args.max_wait_seconds,
    )
    conversation_url = (
        conversation.get('conversation_url')
        or f'{OPENHANDS_BASE_URL}/conversations/{app_conversation_id}'
    )
    session_api_key_value = conversation.get('session_api_key')
    if session_api_key_value and not isinstance(session_api_key_value, str):
        raise RuntimeError(
            'session_api_key had unexpected type in the OpenHands conversation: '
            f'{type(session_api_key_value).__name__}'
        )
    session_api_key = session_api_key_value or ''
    agent_server_url = extract_agent_server_url(conversation_url)

    agent_text = ''
    if agent_server_url and session_api_key:
        try:
            agent_text = fetch_agent_server_final_response(
                app_conversation_id,
                agent_server_url,
                session_api_key,
            )
        except RuntimeError:
            agent_text = ''
    if not agent_text:
        events = fetch_app_server_events(app_conversation_id)
        try:
            agent_text = extract_last_agent_text(events)
        except RuntimeError as exc:
            if not session_api_key:
                raise RuntimeError(
                    'App server events did not contain assistant text and '
                    'session_api_key was missing from the OpenHands conversation'
                ) from exc
            if not agent_server_url:
                raise RuntimeError(
                    'App server events did not contain assistant text and cannot '
                    'extract agent server URL from conversation URL: '
                    f'{conversation_url}'
                ) from exc
            events = fetch_agent_server_events(
                app_conversation_id,
                agent_server_url,
                session_api_key,
            )
            agent_text = extract_last_agent_text(events)
    result = normalize_result(parse_agent_json(agent_text))

    result['issue_number'] = args.issue_number
    result['repository'] = args.repository
    result['app_conversation_id'] = app_conversation_id
    result['conversation_url'] = conversation_url
    result['agent_response'] = agent_text

    output_path = Path(args.output)
    try:
        output_path.write_text(json.dumps(result, indent=2, ensure_ascii=False) + '\n')
    except OSError as exc:
        raise RuntimeError(f'Failed to write output to {output_path}: {exc}') from exc

    print(
        json.dumps(
            {
                'issue_number': result.get('issue_number'),
                'should_comment': result.get('should_comment'),
                'is_duplicate': result.get('is_duplicate'),
                'auto_close_candidate': result.get('auto_close_candidate'),
                'classification': result.get('classification'),
                'confidence': result.get('confidence'),
                'conversation_url': result.get('conversation_url'),
                'output': str(output_path),
            },
            ensure_ascii=False,
        )
    )
    return 0


if __name__ == '__main__':
    try:
        raise SystemExit(main())
    except Exception as exc:  # noqa: BLE001
        print(f'error: {exc}', file=sys.stderr)
        raise