<?php
declare(strict_types=1);

require_once __DIR__ . '/bootstrap.php';

/**
 * Maps tool names × user tiers to LiteLLM model names for Bedrock Claude.
 *
 * These names must match the model_name keys in Colin's litellm_config.yaml.
 * AWS credentials live only in LiteLLM — not in .env, not here.
 *
 * Both models are already in Colin's litellm_config.yaml:
 *   claude-sonnet-bedrock → bedrock/eu.anthropic.claude-sonnet-4-6  (Claude Sonnet 4.6)
 *   claude-haiku-bedrock  → bedrock/eu.anthropic.claude-haiku-4-5-20251001-v1:0 (Claude Haiku 4.5)
 * AWS IAM key: AKIA46PTFRQF2CQ47ANX (bnl-bedrock user, AmazonBedrockFullAccess)
 */
final class DbnBedrockModelRouter
{
    // LiteLLM model name constants (must match litellm_config.yaml on Colin)
    public const LITELLM_SONNET = 'claude-sonnet-bedrock';
    public const LITELLM_HAIKU  = 'claude-haiku-bedrock';
    // Opus — future premium tier; add 'claude-opus-bedrock' to litellm_config.yaml on Colin first
    public const LITELLM_OPUS   = 'claude-opus-bedrock';

    // Actual Bedrock model IDs routed by LiteLLM (for reference)
    public const BEDROCK_SONNET = 'eu.anthropic.claude-sonnet-4-6';
    public const BEDROCK_HAIKU  = 'eu.anthropic.claude-haiku-4-5-20251001-v1:0';
    public const BEDROCK_OPUS   = 'eu.anthropic.claude-opus-4-7'; // not yet in litellm_config.yaml

    // Models that support extended thinking (via LiteLLM thinking param passthrough)
    private const THINKING_MODELS = [
        self::LITELLM_SONNET,
        // self::LITELLM_OPUS, // uncomment after claude-opus-bedrock added to litellm_config.yaml
    ];

    // Tools pinned to Azure GPT-4o-mini regardless of DBN_BEDROCK_ENABLED.
    // These are mechanical/structural — regex, date extraction, translation — no quality gain from Claude.
    private const AZURE_PINNED = ['redact', 'translate', 'timeline', 'search-legal', 'search'];

    // Tools routed to Claude Haiku 4.5 (fast, good Norwegian comprehension, 4x cheaper than Sonnet).
    // Pro users escalate to Sonnet.
    private const HAIKU_TOOLS = ['ask', 'summarize', 'timeline-deep', 'citations'];

    /**
     * Returns ['gateway' => 'azure'|'bedrock', 'model' => string|null].
     * gateway='azure' means always use Azure regardless of DBN_BEDROCK_ENABLED.
     * gateway='bedrock' means use Bedrock when enabled, fall back to Azure when not.
     * model is null for azure-pinned tools (caller uses DbnAzureOpenAiGateway directly).
     */
    public static function routeForTool(string $tool, string $tier = 'free'): array
    {
        $tier = in_array($tier, ['free', 'plus', 'pro'], true) ? $tier : 'free';

        if (in_array($tool, self::AZURE_PINNED, true)) {
            return ['gateway' => 'azure', 'model' => null];
        }

        if (in_array($tool, self::HAIKU_TOOLS, true)) {
            // Pro users get Sonnet for these tools; free/plus get Haiku
            $model = ($tier === 'pro') ? self::LITELLM_SONNET : self::LITELLM_HAIKU;
            return ['gateway' => 'bedrock', 'model' => $model];
        }

        // All drafting/reasoning tools → Sonnet (korrespond, legal-analysis, deep-research,
        // barnevernet-analyze, discrepancy-find, advocate)
        return ['gateway' => 'bedrock', 'model' => self::LITELLM_SONNET];
    }

    /** @deprecated Use routeForTool() — kept for any direct callers outside the factory. */
    public static function modelForTool(string $tool, string $tier = 'free'): string
    {
        $route = self::routeForTool($tool, $tier);
        return $route['model'] ?? self::LITELLM_SONNET;
    }

    /**
     * Maps a quality-tier engine string to the LiteLLM deployment name passed to
     * withDeployment(). claude_haiku/claude_sonnet route to Bedrock Claude when the
     * active gateway is Bedrock; otherwise they degrade to the Azure GPT-4o family.
     */
    public static function deploymentForEngine(string $engine, bool $isBedrock): string
    {
        switch ($engine) {
            case 'claude_sonnet': return $isBedrock ? self::LITELLM_SONNET : 'gpt-4o';
            case 'claude_haiku':  return $isBedrock ? self::LITELLM_HAIKU  : 'gpt-4o-mini';
            case 'azure_full':    return 'gpt-4o';
            case 'azure_mini':
            default:              return 'gpt-4o-mini';
        }
    }

    public static function supportsThinking(string $modelName): bool
    {
        return in_array($modelName, self::THINKING_MODELS, true);
    }

    public static function maxTokensForTool(string $tool): int
    {
        return match ($tool) {
            'deep-research', 'barnevernet-analyze', 'advocate' => 4000,
            'legal-analysis', 'korrespond', 'discrepancy-find'  => 3000,
            default                                              => 2000,
        };
    }
}