<?php
/**
 * Google Gemini, through the Gemini API.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Advisor;

defined( 'ABSPATH' ) || exit;

/**
 * Calls https://generativelanguage.googleapis.com from the server with the
 * agency's own key, sent in a header (never in the address, so it can't end
 * up in a log). The key never reaches the browser or an error message.
 */
final class Gemini extends HttpProvider {

	/** API base. */
	const BASE = 'https://generativelanguage.googleapis.com/v1beta/models'; // phpcs:ignore PluginCheck.CodeAnalysis.AIProvider.DirectIntegration -- Bring-your-own-key by design: called only when an administrator asks, and disclosed under External services in readme.txt.

	/**
	 * {@inheritDoc}
	 *
	 * @return string
	 */
	public function id() {
		return 'gemini';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return string
	 */
	public function label() {
		return 'Gemini (Google)';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return string[]
	 */
	public function models() {
		return array( 'gemini-3.5-flash-lite', 'gemini-3.8-flash', 'gemini-3.6-flash', 'gemini-3.1-flash-lite' );
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return string
	 */
	public function default_model() {
		return 'gemini-3.5-flash-lite';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return string
	 */
	public function console() {
		return 'aistudio.google.com';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return string
	 */
	public function key_placeholder() {
		return 'AIza…';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param string  $key          API key.
	 * @param string  $model        Model.
	 * @param string  $instructions Instructions.
	 * @param array[] $messages     Turns.
	 * @param int     $max_tokens   Longest answer.
	 * @return array
	 */
	protected function request( $key, $model, $instructions, array $messages, $max_tokens ) {
		$contents = array();
		foreach ( self::turns( $messages ) as $t ) {
			$contents[] = array(
				'role'  => 'assistant' === $t['role'] ? 'model' : 'user',
				'parts' => array( array( 'text' => $t['text'] ) ),
			);
		}
		$id = preg_replace( '#^models/#', '', (string) $model );
		return array(
			'url'     => self::BASE . '/' . rawurlencode( $id ) . ':generateContent',
			'headers' => array( 'x-goog-api-key' => $key ),
			'body'    => array(
				'systemInstruction' => array( 'parts' => array( array( 'text' => (string) $instructions ) ) ),
				'contents'          => $contents,
				// Thinking counts towards the output limit; leave room so the answer fits.
				'generationConfig'  => array( 'maxOutputTokens' => (int) $max_tokens + self::THINKING_ROOM ),
			),
		);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param array $data Decoded reply.
	 * @return array
	 */
	protected function parse( array $data ) {
		$c     = isset( $data['candidates'][0] ) && is_array( $data['candidates'][0] ) ? $data['candidates'][0] : array();
		$parts = array();
		foreach ( isset( $c['content']['parts'] ) && is_array( $c['content']['parts'] ) ? $c['content']['parts'] : array() as $p ) {
			if ( is_array( $p ) && isset( $p['text'] ) && is_string( $p['text'] ) && empty( $p['thought'] ) ) {
				$parts[] = (string) $p['text'];
			}
		}
		$u = isset( $data['usageMetadata'] ) && is_array( $data['usageMetadata'] ) ? $data['usageMetadata'] : array();
		return array(
			'text' => implode( '', $parts ),
			'in'   => isset( $u['promptTokenCount'] ) ? (int) $u['promptTokenCount'] : 0,
			'out'  => ( isset( $u['candidatesTokenCount'] ) ? (int) $u['candidatesTokenCount'] : 0 ) + ( isset( $u['thoughtsTokenCount'] ) ? (int) $u['thoughtsTokenCount'] : 0 ),
			'cut'  => isset( $c['finishReason'] ) && 'MAX_TOKENS' === $c['finishReason'],
		);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param int   $code HTTP status.
	 * @param array $data Decoded reply.
	 * @return string
	 */
	public function classify( $code, array $data ) {
		$status = isset( $data['error']['status'] ) ? strtoupper( (string) $data['error']['status'] ) : '';
		$msg    = isset( $data['error']['message'] ) ? strtolower( (string) $data['error']['message'] ) : '';
		$reason = strtoupper( (string) wp_json_encode( isset( $data['error']['details'] ) ? $data['error']['details'] : array() ) );
		if ( 401 === $code || 'UNAUTHENTICATED' === $status || false !== strpos( $reason, 'API_KEY_INVALID' ) || false !== strpos( $msg, 'api key not valid' ) ) {
			return 'auth';
		}
		if ( false !== strpos( $msg, 'location is not supported' ) || false !== strpos( $msg, 'user location' ) ) {
			return 'region';
		}
		if ( 429 === $code || 'RESOURCE_EXHAUSTED' === $status ) {
			return false !== strpos( $msg, 'billing' ) || false !== strpos( $msg, 'exceeded your current quota' ) ? 'quota' : 'rate_limit';
		}
		if ( false !== strpos( $msg, 'exceeds the maximum number of tokens' ) || false !== strpos( $msg, 'too long' ) ) {
			return 'too_large';
		}
		if ( 404 === $code || 'NOT_FOUND' === $status ) {
			return 'model';
		}
		if ( 403 === $code || 'PERMISSION_DENIED' === $status ) {
			return 'permission';
		}
		if ( $code >= 500 ) {
			return 'server';
		}
		return 'bad_request';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param array $data Decoded reply.
	 * @return array
	 */
	protected function said( array $data ) {
		return array(
			isset( $data['error']['message'] ) ? (string) $data['error']['message'] : '',
			isset( $data['error']['status'] ) ? (string) $data['error']['status'] : '',
		);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param string $key API key.
	 * @return array
	 */
	protected function models_request( $key ) {
		return array(
			'url'     => self::BASE . '?pageSize=200',
			'headers' => array( 'x-goog-api-key' => $key ),
		);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param array $data Decoded reply.
	 * @return string[]
	 */
	protected function models_parse( array $data ) {
		$out = array();
		foreach ( isset( $data['models'] ) && is_array( $data['models'] ) ? $data['models'] : array() as $m ) {
			$name = is_array( $m ) && isset( $m['name'] ) && is_string( $m['name'] ) ? preg_replace( '#^models/#', '', $m['name'] ) : '';
			$can  = is_array( $m ) && isset( $m['supportedGenerationMethods'] ) ? (array) $m['supportedGenerationMethods'] : array();
			if ( 0 === strpos( $name, 'gemini' ) && in_array( 'generateContent', $can, true ) && ! preg_match( '/(embedding|image|tts|audio|live)/', $name ) ) {
				$out[] = $name;
			}
		}
		return $out;
	}
}