<?php
header('Content-Type: application/json');
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: POST, GET, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type, x-api-key, anthropic-version, Authorization');
if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') { http_response_code(200); exit; }

$input = json_decode(file_get_contents('php://input'), true);
$uri = $_SERVER['REQUEST_URI'] ?? '';
$is_msg = ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($input['messages']));

if ($is_msg) {
    $msgs = $input['messages'] ?? [];
    $sys = $input['system'] ?? '';
    $max = $input['max_tokens'] ?? 4096;
    $stream = $input['stream'] ?? false;
    $model = $input['model'] ?? 'wevia-sovereign';
    $tools = $input['tools'] ?? [];

    // Convert Anthropic system (can be string or array of blocks)
    $oai = [];
    if ($sys) {
        $t = is_array($sys) ? implode("\n", array_map(fn($b) => $b['text'] ?? '', $sys)) : $sys;
        // For Paperclip agents: add strong instruction preamble
        $t = "IMPORTANT: You are an AI agent in the Paperclip orchestration platform. Follow ALL instructions in this system prompt precisely. Execute tasks, not conversation.\n\n" . $t;
        $oai[] = ['role' => 'system', 'content' => $t];
    }

    // Convert messages, handling tool_use and tool_result blocks
    foreach ($msgs as $m) {
        $c = $m['content'];
        if (is_array($c)) {
            $p = [];
            foreach ($c as $b) {
                if (is_string($b)) { $p[] = $b; continue; }
                $type = $b['type'] ?? '';
                if ($type === 'text') { $p[] = $b['text']; }
                elseif ($type === 'tool_use') {
                    $p[] = "[TOOL_CALL: " . ($b['name'] ?? '?') . "] Input: " . json_encode($b['input'] ?? []);
                }
                elseif ($type === 'tool_result') {
                    $content = $b['content'] ?? '';
                    if (is_array($content)) {
                        $content = implode("\n", array_map(fn($x) => $x['text'] ?? json_encode($x), $content));
                    }
                    $p[] = "[TOOL_RESULT: " . ($b['tool_use_id'] ?? '?') . "] " . $content;
                }
                else { $p[] = json_encode($b); }
            }
            $c = implode("\n", $p);
        }
        $oai[] = ['role' => $m['role'], 'content' => $c];
    }

    // If tools are defined, append tool descriptions to system
    if (!empty($tools)) {
        $tool_desc = "\n\n## Available Tools\n";
        foreach ($tools as $tool) {
            $name = $tool['name'] ?? '?';
            $desc = $tool['description'] ?? '';
            $tool_desc .= "- {$name}: {$desc}\n";
        }
        $tool_desc .= "\nTo use a tool, respond with a JSON block: {\"tool\": \"name\", \"input\": {...}}\n";
        if (!empty($oai) && $oai[0]['role'] === 'system') {
            $oai[0]['content'] .= $tool_desc;
        }
    }

    $secrets=[]; foreach(@file('/etc/weval/secrets.env',FILE_IGNORE_NEW_LINES|FILE_SKIP_EMPTY_LINES)?:[] as $_l){if($_l[0]==='#'||strpos($_l,'=')===false)continue;$_p=explode('=',$_l,2);$secrets[trim($_p[0])]=trim($_p[1]);}

    // CASCADE: Anthropic Claude (real) -> Cerebras 235B -> Groq
    $anthropic_key = $secrets['ANTHROPIC_KEY'] ?? '';
    $providers = [];
    if ($anthropic_key) {
        $providers[] = ['url' => 'https://api.anthropic.com/v1/messages', 'key' => $anthropic_key, 'model' => 'claude-sonnet-4-20250514', 'is_anthropic' => true];
    }
    $providers[] = ['url' => 'https://api.cerebras.ai/v1/chat/completions', 'key' => '', 'model' => 'qwen-3-235b-a22b-instruct-2507'];

    // Load keys and set in providers
    $cerebras_key = $secrets['CEREBRAS_API_KEY'] ?? '';
    $groq_key = $secrets['GROQ_KEY'] ?? '';
    // Set Cerebras key in the Cerebras provider (index depends on Anthropic presence)
    foreach ($providers as &$p) {
        if (strpos($p['url'], 'cerebras') !== false && $cerebras_key) {
            $p['key'] = $cerebras_key;
        }
    }
    unset($p);
    // Add Groq as final fallback
    if ($groq_key) {
        $providers[] = ['url' => 'https://api.groq.com/openai/v1/chat/completions', 'key' => $groq_key, 'model' => 'llama-3.3-70b-versatile'];
    }

    $resp = null; $hc = 0;
    foreach ($providers as $prov) {
        $payload = [
            'model' => $prov['model'],
            'messages' => $oai,
            'max_tokens' => min($max, 8192),
            'temperature' => 0.1, // Low temp for agent tasks
        ];
        $headers = ['Content-Type: application/json'];
        if (isset($prov['is_anthropic']) && $prov['is_anthropic']) {
            $headers[] = 'x-api-key: ' . $prov['key'];
            $headers[] = 'anthropic-version: 2023-06-01';
            $payload = ['model' => $prov['model'], 'messages' => $oai, 'max_tokens' => min($max, 8192)];
        } elseif ($prov['key']) { $headers[] = 'Authorization: Bearer ' . $prov['key']; }

        $ch = curl_init($prov['url']);
        curl_setopt_array($ch, [
            CURLOPT_POST => true,
            CURLOPT_POSTFIELDS => json_encode($payload),
            CURLOPT_HTTPHEADER => $headers,
            CURLOPT_RETURNTRANSFER => true, CURLOPT_TIMEOUT => 120, CURLOPT_SSL_VERIFYPEER => false,
        ]);
        $resp = curl_exec($ch);
        $hc = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        curl_close($ch);
        if ($hc === 200 && $resp) break;
    }

    if ($hc !== 200 || !$resp) {
        http_response_code(500);
        die(json_encode(['error'=>['type'=>'api_error','message'=>'All providers failed. HC='.$hc]]));
    }

    $r = json_decode($resp, true);
    $txt = '';
    if (isset($r['content']) && is_array($r['content'])) { $txt = $r['content'][0]['text'] ?? ''; }
    elseif (isset($r['choices'])) { $txt = $r['choices'][0]['message']['content'] ?? ''; }
    $u = $r['usage'] ?? [];
    $mid = 'msg_wevia_' . substr(md5(uniqid()), 0, 12);

    if ($stream) {
        header('Content-Type: text/event-stream');
        header('Cache-Control: no-cache');
        echo "event: message_start\ndata: ".json_encode(['type'=>'message_start','message'=>['id'=>$mid,'type'=>'message','role'=>'assistant','content'=>[],'model'=>$model,'stop_reason'=>null,'usage'=>['input_tokens'=>$u['prompt_tokens']??0,'output_tokens'=>0]]])."\n\n";
        echo "event: content_block_start\ndata: ".json_encode(['type'=>'content_block_start','index'=>0,'content_block'=>['type'=>'text','text'=>'']])."\n\n";
        foreach (str_split($txt, 40) as $ck) {
            echo "event: content_block_delta\ndata: ".json_encode(['type'=>'content_block_delta','index'=>0,'delta'=>['type'=>'text_delta','text'=>$ck]])."\n\n";
            flush(); usleep(5000);
        }
        echo "event: content_block_stop\ndata: {\"type\":\"content_block_stop\",\"index\":0}\n\n";
        echo "event: message_delta\ndata: ".json_encode(['type'=>'message_delta','delta'=>['stop_reason'=>'end_turn'],'usage'=>['output_tokens'=>$u['completion_tokens']??0]])."\n\n";
        echo "event: message_stop\ndata: {\"type\":\"message_stop\"}\n\n";
        flush();
    } else {
        echo json_encode(['id'=>$mid,'type'=>'message','role'=>'assistant','content'=>[['type'=>'text','text'=>$txt]],'model'=>$model,'stop_reason'=>'end_turn','stop_sequence'=>null,'usage'=>['input_tokens'=>$u['prompt_tokens']??0,'output_tokens'=>$u['completion_tokens']??0]]);
    }
    exit;
}
if (strpos($uri,'models')!==false) {
    echo json_encode(['data'=>[
        ['id'=>'wevia-sovereign','object'=>'model','created'=>time()],
        ['id'=>'claude-sonnet-4-6','object'=>'model','created'=>time()],
        ['id'=>'claude-opus-4-6','object'=>'model','created'=>time()],
    ]]);
    exit;
}
echo json_encode(['status'=>'ok','engine'=>'WEVIA Anthropic Proxy','sovereign'=>true,'v'=>'3.0','note'=>'For full Paperclip agent functionality, set a real ANTHROPIC_API_KEY (sk-ant-*)']);