proxy.php

<?php
// SSE proxy between Kobo frontend and OpenCode server
// Persists session ID in a file so chat history is preserved across messages

// CORS: default allow-all for compatibility; set OPENCODE_CORS_ORIGIN to tighten.
$corsOrigin = getenv('OPENCODE_CORS_ORIGIN');
if (!$corsOrigin) {
    $corsOrigin = '*';
}
header('Access-Control-Allow-Origin: ' . $corsOrigin);
header('Access-Control-Allow-Methods: GET, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type');

if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') {
    http_response_code(200);
    exit;
}

while (ob_get_level()) ob_end_clean();

$prompt = isset($_GET['prompt']) ? $_GET['prompt'] : '';
$opencode = getenv('OPENCODE_URL');
if (!$opencode) {
    $opencode = 'http://127.0.0.1:4096';
}
$opencode = rtrim($opencode, '/');
$sessionFile = __DIR__ . '/.opencode_session';

if (empty($prompt) && !isset($_GET['history']) && !isset($_GET['sessions']) && !isset($_GET['load'])) {
    header('Content-Type: text/event-stream');
    header('Cache-Control: no-cache');
    header('Connection: keep-alive');
    echo "data: " . json_encode(array('error' => 'No prompt provided')) . "\n\n";
    echo "data: [DONE]\n\n";
    flush();
    exit;
}

// Helper: make a JSON request to the OpenCode server using curl CLI
function opencode_request($method, $url, $body = null) {
    $cmd = 'curl -s -X ' . escapeshellarg($method) . ' ' . escapeshellarg($url);
    $cmd .= ' -H "Content-Type: application/json"';
    if ($body !== null) {
        $cmd .= ' -d ' . escapeshellarg(json_encode($body));
    }

    $descriptors = array(
        0 => array('pipe', 'r'),
        1 => array('pipe', 'w'),
        2 => array('pipe', 'w')
    );

    $proc = proc_open($cmd, $descriptors, $pipes);
    if (!is_resource($proc)) {
        return null;
    }
    fclose($pipes[0]);
    $output = stream_get_contents($pipes[1]);
    fclose($pipes[1]);
    fclose($pipes[2]);
    proc_close($proc);

    return json_decode($output, true);
}

// Handle history/import request (returns JSON, not SSE)
if (isset($_GET['history'])) {
    header('Content-Type: application/json');

    if (!file_exists($sessionFile)) {
        echo json_encode(array('error' => 'No session found'));
        exit;
    }

    $savedID = trim(file_get_contents($sessionFile));
    if ($savedID === '') {
        echo json_encode(array('error' => 'Empty session ID'));
        exit;
    }

    // GET /session/{id}/message returns array of {info: {role, ...}, parts: [{type, text, ...}]}
    $messages = opencode_request('GET', $opencode . '/session/' . $savedID . '/message');
    if ($messages === null) {
        echo json_encode(array('error' => 'Failed to fetch messages from server'));
        exit;
    }

    echo json_encode($messages);
    exit;
}

// Handle sessions list request (returns JSON list of recent sessions)
if (isset($_GET['sessions'])) {
    header('Content-Type: application/json');

    $limit = isset($_GET['limit']) ? intval($_GET['limit']) : 20;
    $sessions = opencode_request('GET', $opencode . '/session?limit=' . $limit);
    if ($sessions === null) {
        echo json_encode(array('error' => 'Failed to fetch sessions'));
        exit;
    }

    echo json_encode($sessions);
    exit;
}

// Handle load session request (switches to an existing session and returns its messages)
if (isset($_GET['load'])) {
    header('Content-Type: application/json');

    $loadID = $_GET['load'];
    if ($loadID === '') {
        echo json_encode(array('error' => 'No session ID provided'));
        exit;
    }

    // Verify session exists
    $session = opencode_request('GET', $opencode . '/session/' . $loadID);
    if (!$session || !isset($session['id'])) {
        echo json_encode(array('error' => 'Session not found'));
        exit;
    }

    // Save this session ID so subsequent prompts go to it
    file_put_contents($sessionFile, $loadID);

    // Return its messages
    $messages = opencode_request('GET', $opencode . '/session/' . $loadID . '/message');
    if ($messages === null) {
        echo json_encode(array('error' => 'Failed to fetch messages'));
        exit;
    }

    echo json_encode($messages);
    exit;
}

// Streaming response (SSE)
header('Content-Type: text/event-stream');
header('Cache-Control: no-cache');
header('Connection: keep-alive');

// 1. Get or create session
$sessionID = null;

// Try to reuse existing session
if (file_exists($sessionFile)) {
    $savedID = trim(file_get_contents($sessionFile));
    if ($savedID !== '') {
        // Verify session still exists
        $check = opencode_request('GET', $opencode . '/session/' . $savedID);
        if ($check && isset($check['id'])) {
            $sessionID = $savedID;
        }
    }
}

// Create new session if needed
if ($sessionID === null) {
    $session = opencode_request('POST', $opencode . '/session', new stdClass());
    if (!$session || !isset($session['id'])) {
        echo "data: " . json_encode(array('error' => 'Failed to create session')) . "\n\n";
        echo "data: [DONE]\n\n";
        flush();
        exit;
    }
    $sessionID = $session['id'];
    file_put_contents($sessionFile, $sessionID);
}

// 2. Connect to the /event SSE stream via curl subprocess (long-lived)
$sseCmd = 'curl -sN ' . escapeshellarg($opencode . '/event');
$sseDescriptors = array(
    0 => array('pipe', 'r'),
    1 => array('pipe', 'w'),
    2 => array('pipe', 'w')
);
$sseProc = proc_open($sseCmd, $sseDescriptors, $ssePipes);
if (!is_resource($sseProc)) {
    echo "data: " . json_encode(array('error' => 'Failed to connect to event stream')) . "\n\n";
    echo "data: [DONE]\n\n";
    flush();
    exit;
}
fclose($ssePipes[0]);

// Wait for SSE connection to establish (server.connected event)
// Read lines until we see server.connected, discarding any buffered events
stream_set_blocking($ssePipes[1], true);
stream_set_timeout($ssePipes[1], 5);
$connected = false;
$connectAttempts = 0;
while (!$connected && $connectAttempts < 20) {
    $connectLine = fgets($ssePipes[1]);
    $connectAttempts++;
    if ($connectLine === false) break;
    $connectLine = trim($connectLine);
    if (strpos($connectLine, 'data: ') === 0) {
        $connectData = json_decode(substr($connectLine, 6), true);
        if ($connectData && isset($connectData['type']) && $connectData['type'] === 'server.connected') {
            $connected = true;
            fgets($ssePipes[1]); // consume trailing blank line
        }
    }
}
if (!$connected) {
    echo "data: " . json_encode(array('error' => 'Failed to establish SSE connection')) . "\n\n";
    echo "data: [DONE]\n\n";
    flush();
    fclose($ssePipes[1]);
    fclose($ssePipes[2]);
    proc_close($sseProc);
    exit;
}

// 3. Send the prompt asynchronously
// Read provider/model from query params, fall back to anthropic/claude-haiku-4-5
$providerID = isset($_GET['provider']) ? $_GET['provider'] : 'anthropic';
$modelID = isset($_GET['model']) ? $_GET['model'] : 'claude-haiku-4-5';

$promptBody = array(
    'model' => array(
        'providerID' => $providerID,
        'modelID' => $modelID
    ),
    'parts' => array(
        array(
            'type' => 'text',
            'text' => $prompt
        )
    )
);
$promptJson = json_encode($promptBody);
$promptUrl = $opencode . '/session/' . $sessionID . '/prompt_async';
$promptCmd = 'curl -s -X POST ' . escapeshellarg($promptUrl)
    . ' -H "Content-Type: application/json"'
    . ' -d ' . escapeshellarg($promptJson)
    . ' -o /dev/null -w "%{http_code}"';
$promptDescriptors = array(
    0 => array('pipe', 'r'),
    1 => array('pipe', 'w'),
    2 => array('pipe', 'w')
);
$promptProc = proc_open($promptCmd, $promptDescriptors, $promptPipes);
if (is_resource($promptProc)) {
    fclose($promptPipes[0]);
    $httpCode = trim(stream_get_contents($promptPipes[1]));
    fclose($promptPipes[1]);
    fclose($promptPipes[2]);
    proc_close($promptProc);

    if ($httpCode !== '204' && $httpCode !== '200') {
        echo "data: " . json_encode(array('error' => 'Failed to send prompt (HTTP ' . $httpCode . ')')) . "\n\n";
        echo "data: [DONE]\n\n";
        flush();
        fclose($ssePipes[1]);
        fclose($ssePipes[2]);
        proc_close($sseProc);
        exit;
    }
} else {
    echo "data: " . json_encode(array('error' => 'Failed to start prompt request')) . "\n\n";
    echo "data: [DONE]\n\n";
    flush();
    fclose($ssePipes[1]);
    fclose($ssePipes[2]);
    proc_close($sseProc);
    exit;
}

// 4. Read SSE events and forward text deltas to the frontend
$wordBuffer = '';
$done = false;
$assistantMsgID = '';
$sawAssistantText = false;
$sentTools = array(); // Track which tool parts we've already sent 'running' for (keyed by part ID)
$timeout = 120; // seconds
$startTime = time();

stream_set_timeout($ssePipes[1], 2);

while (!$done && (time() - $startTime) < $timeout) {
    $line = fgets($ssePipes[1]);

    if ($line === false) {
        $status = proc_get_status($sseProc);
        if (!$status['running']) {
            break;
        }
        continue;
    }

    $line = trim($line);

    // Skip empty lines and SSE comments
    if ($line === '' || $line[0] === ':') {
        continue;
    }

    if (strpos($line, 'data: ') !== 0) {
        continue;
    }

    $data = substr($line, 6);
    $event = json_decode($data, true);
    if (!$event || !isset($event['type'])) {
        continue;
    }

    $type = $event['type'];
    $props = isset($event['properties']) ? $event['properties'] : array();

    // Track the assistant message ID so we only forward its text parts
    if ($type === 'message.updated') {
        $info = isset($props['info']) ? $props['info'] : array();
        if (isset($info['role']) && $info['role'] === 'assistant' &&
            isset($info['sessionID']) && $info['sessionID'] === $sessionID) {
            $assistantMsgID = $info['id'];
        }

        // Check for errors on the assistant message
        if (isset($info['error']) && isset($info['id']) && $info['id'] === $assistantMsgID) {
            $errMsg = 'AI error';
            if (isset($info['error']['data']['message'])) {
                $errMsg = $info['error']['data']['message'];
            } elseif (isset($info['error']['name'])) {
                $errMsg = $info['error']['name'];
            }
            echo "data: " . json_encode(array('error' => $errMsg)) . "\n\n";
            flush();
            $done = true;
        }
    }

    // Forward text deltas and tool status from the assistant message only
    if ($type === 'message.part.updated') {
        $part = isset($props['part']) ? $props['part'] : null;
        $delta = isset($props['delta']) ? $props['delta'] : null;

        // Forward tool steps (just name + status), deduplicated by part ID
        if ($part && isset($part['type']) && $part['type'] === 'tool' &&
            isset($part['messageID']) && $part['messageID'] === $assistantMsgID) {

            $partID = isset($part['id']) ? $part['id'] : '';
            $toolName = isset($part['tool']) ? $part['tool'] : 'unknown';
            $state = isset($part['state']) ? $part['state'] : array();
            $toolStatus = isset($state['status']) ? $state['status'] : '';
            $title = isset($state['title']) ? $state['title'] : '';
            if ($title === '' && isset($state['input']) && isset($state['input']['description'])) {
                $title = $state['input']['description'];
            }

            // Only send on meaningful status changes, and deduplicate 'running'
            $shouldSend = false;
            if ($toolStatus === 'running') {
                if ($partID !== '' && !isset($sentTools[$partID])) {
                    $sentTools[$partID] = 'running';
                    $shouldSend = true;
                } elseif ($partID === '') {
                    // No part ID available, fall back to sending
                    $shouldSend = true;
                }
                // If already sent 'running' for this partID, skip
            } elseif ($toolStatus === 'completed' || $toolStatus === 'error') {
                $shouldSend = true;
                if ($partID !== '') {
                    $sentTools[$partID] = $toolStatus;
                }
            }

            if ($shouldSend) {
                $sawAssistantText = true;
                // Flush any pending text buffer first
                if ($wordBuffer !== '') {
                    echo "data: " . json_encode(array('text' => $wordBuffer)) . "\n\n";
                    flush();
                    $wordBuffer = '';
                }
                $toolEvent = array(
                    'tool' => $toolName,
                    'status' => $toolStatus,
                    'title' => $title
                );
                if ($partID !== '') {
                    $toolEvent['id'] = $partID;
                }
                echo "data: " . json_encode($toolEvent) . "\n\n";
                flush();
            }
        }

        if ($part && isset($part['type']) && $part['type'] === 'text' &&
            isset($part['messageID']) && $part['messageID'] === $assistantMsgID) {

            if ($delta !== null && $delta !== '') {
                $sawAssistantText = true;
                $wordBuffer .= $delta;

                // Count complete words and flush every ~5
                $trimmed = trim($wordBuffer);
                if ($trimmed !== '') {
                    $endsWithSpace = preg_match('/\s$/', $wordBuffer);
                    $words = preg_split('/\s+/', $trimmed);
                    $completeWordCount = $endsWithSpace ? count($words) : count($words) - 1;

                    if ($completeWordCount >= 5) {
                        echo "data: " . json_encode(array('text' => $wordBuffer)) . "\n\n";
                        flush();
                        $wordBuffer = '';
                    }
                }
            }

            // When a text part finishes, flush the buffer but do NOT stop --
            // there may be more steps (tool calls followed by more text)
            if (isset($part['time']) && isset($part['time']['end']) && $part['time']['end'] > 0) {
                if ($wordBuffer !== '') {
                    echo "data: " . json_encode(array('text' => $wordBuffer)) . "\n\n";
                    flush();
                    $wordBuffer = '';
                }
            }
        }
    }

    // Session error
    if ($type === 'session.error') {
        if (isset($props['sessionID']) && $props['sessionID'] === $sessionID) {
            $errMsg = 'Session error';
            if (isset($props['error']['data']['message'])) {
                $errMsg = $props['error']['data']['message'];
            } elseif (isset($props['error']['name'])) {
                $errMsg = $props['error']['name'];
            }
            echo "data: " . json_encode(array('error' => $errMsg)) . "\n\n";
            flush();
            $done = true;
        }
    }

    // Session idle = done (only after we've seen assistant text)
    if ($type === 'session.idle' || $type === 'session.status') {
        $matchSession = false;
        if ($type === 'session.idle' && isset($props['sessionID']) && $props['sessionID'] === $sessionID) {
            $matchSession = true;
        }
        if ($type === 'session.status' && isset($props['sessionID']) && $props['sessionID'] === $sessionID) {
            $statusObj = isset($props['status']) ? $props['status'] : array();
            $statusType = isset($statusObj['type']) ? $statusObj['type'] : '';
            if ($statusType === 'idle') {
                $matchSession = true;
            }
        }
        if ($matchSession && $sawAssistantText) {
            $done = true;
        }
    }

    if (connection_aborted()) {
        break;
    }
}

// Flush remaining buffer
if ($wordBuffer !== '') {
    echo "data: " . json_encode(array('text' => $wordBuffer)) . "\n\n";
    flush();
}

echo "data: [DONE]\n\n";
flush();

// Cleanup SSE connection (but NOT the session -- keep it for history)
fclose($ssePipes[1]);
fclose($ssePipes[2]);
proc_close($sseProc);
?>