<?php
/**
 * Anthropic Claude, through the Messages API.
 *
 * @package TurtleReport
 */

namespace TurtleReport\Advisor;

defined( 'ABSPATH' ) || exit;

/**
 * Calls https://api.anthropic.com/v1/messages from the server with the
 * agency's own key. The key never reaches the browser or an error message.
 */
final class Anthropic extends HttpProvider {

	/** Endpoint. */
	const URL = 'https://api.anthropic.com/v1/messages'; // 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.

	/** Model list. */
	const MODELS_URL = 'https://api.anthropic.com/v1/models'; // phpcs:ignore PluginCheck.CodeAnalysis.AIProvider.DirectIntegration -- Lists the models the agency's own key can use, on request in Settings.

	/** API version header. */
	const VERSION = '2023-06-01';

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

	/**
	 * {@inheritDoc}
	 *
	 * @return string
	 */
	public function label() {
		return 'Claude (Anthropic)';
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return string[]
	 */
	public function models() {
		return array( 'claude-haiku-5-5', 'claude-sonnet-5-5', 'claude-opus-5-5' );
	}

	/**
	 * {@inheritDoc}
	 *
	 * @return string
	 */
	public function default_model() {
		return 'claude-haiku-5-5';
	}

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

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

	/**
	 * {@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 ) {
		$turns = array();
		foreach ( self::turns( $messages ) as $t ) {
			$turns[] = array(
				'role'    => $t['role'],
				'content' => $t['text'],
			);
		}
		return array(
			'url'     => self::URL,
			'headers' => $this->headers( $key ),
			'body'    => array(
				'model'      => (string) $model,
				'system'     => (string) $instructions,
				'messages'   => $turns,
				// Thinking counts towards max_tokens; leave room so the answer fits.
				'max_tokens' => (int) $max_tokens + self::THINKING_ROOM,
			),
		);
	}

	/**
	 * Headers.
	 *
	 * @param string $key API key.
	 * @return array
	 */
	private function headers( $key ) {
		return array(
			'x-api-key'         => $key,
			'anthropic-version' => self::VERSION,
		);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param array $data Decoded reply.
	 * @return array
	 */
	protected function parse( array $data ) {
		$parts = array();
		foreach ( isset( $data['content'] ) && is_array( $data['content'] ) ? $data['content'] : array() as $block ) {
			if ( is_array( $block ) && isset( $block['type'], $block['text'] ) && is_string( $block['text'] ) && 'text' === $block['type'] ) {
				$parts[] = (string) $block['text'];
			}
		}
		return array(
			'text' => implode( "\n\n", $parts ),
			'in'   => isset( $data['usage']['input_tokens'] ) ? (int) $data['usage']['input_tokens'] : 0,
			'out'  => isset( $data['usage']['output_tokens'] ) ? (int) $data['usage']['output_tokens'] : 0,
			'cut'  => isset( $data['stop_reason'] ) && 'max_tokens' === $data['stop_reason'],
		);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param int   $code HTTP status.
	 * @param array $data Decoded reply.
	 * @return string
	 */
	public function classify( $code, array $data ) {
		$type = isset( $data['error']['type'] ) ? strtolower( (string) $data['error']['type'] ) : '';
		$msg  = isset( $data['error']['message'] ) ? strtolower( (string) $data['error']['message'] ) : '';
		if ( 401 === $code || 'authentication_error' === $type ) {
			return 'auth';
		}
		if ( false !== strpos( $msg, 'credit balance' ) || 'billing_error' === $type ) {
			return 'quota';
		}
		if ( 413 === $code || 'request_too_large' === $type || false !== strpos( $msg, 'prompt is too long' ) ) {
			return 'too_large';
		}
		if ( 429 === $code || 'rate_limit_error' === $type ) {
			return 'rate_limit';
		}
		if ( 404 === $code || 'not_found_error' === $type ) {
			return 'model';
		}
		if ( 403 === $code || 'permission_error' === $type ) {
			return false !== strpos( $msg, 'region' ) || false !== strpos( $msg, 'country' ) ? 'region' : 'permission';
		}
		if ( $code >= 500 || 'overloaded_error' === $type || 'api_error' === $type ) {
			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']['type'] ) ? (string) $data['error']['type'] : '',
		);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param string $key API key.
	 * @return array
	 */
	protected function models_request( $key ) {
		return array(
			'url'     => self::MODELS_URL . '?limit=100',
			'headers' => $this->headers( $key ),
		);
	}

	/**
	 * {@inheritDoc}
	 *
	 * @param array $data Decoded reply.
	 * @return string[]
	 */
	protected function models_parse( array $data ) {
		$out = array();
		foreach ( isset( $data['data'] ) && is_array( $data['data'] ) ? $data['data'] : array() as $m ) {
			if ( is_array( $m ) && isset( $m['id'] ) && is_string( $m['id'] ) && 0 === strpos( $m['id'], 'claude' ) ) {
				$out[] = (string) $m['id'];
			}
		}
		return $out;
	}
}