<?php
/**
 * Builds the file set for a Capacitor WebView-wrapper Android project
 * from a Mobile_App_Config — the exact bytes Esipher commits into the
 * app repo, where the bundled GitHub Actions workflow
 * (templates/capacitor-build.yml.tpl) turns them into a debug APK and a
 * signed release AAB.
 *
 * The generated project deliberately commits only source: package.json,
 * capacitor.config.json, a tiny offline fallback page, the icon/splash
 * source images, and the workflow. `android/` is recreated from scratch
 * in CI (`npx cap add android`), so it's git-ignored, not committed.
 *
 * @package Esipher
 */

namespace Esipher;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * One entry point: files().
 */
class Mobile_App_Project {

	const CAP_VERSION    = '^6.1.0';
	const ASSETS_VERSION = '^3.0.5';

	const ICON_SIZE   = 1024;
	const SPLASH_SIZE = 2732;

	/**
	 * @param Mobile_App_Config $config
	 *
	 * @return array<string,array{content:string,is_base64:bool}>|\WP_Error
	 *         Map of repo-relative path => file. Text files carry raw
	 *         content (is_base64 false); the two PNGs carry base64.
	 */
	public function files( Mobile_App_Config $config, $include_ios = false ) {
		$icon_src = $this->load_icon_bytes( $config->icon_attachment_id );

		if ( is_wp_error( $icon_src ) ) {
			return $icon_src;
		}

		$icon_png   = $this->normalize_icon( $icon_src, $config->background_color );
		$splash_png = $this->render_splash( $icon_png, $config->background_color );

		$workflow_tpl = ESIPHER_PLUGIN_DIR . 'templates/capacitor-build.yml.tpl';
		$workflow     = is_file( $workflow_tpl ) ? (string) file_get_contents( $workflow_tpl ) : ''; // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- reading this plugin's own bundled template.

		if ( '' === $workflow ) {
			return new \WP_Error( 'esipher_app_template_missing', __( 'Esipher\'s bundled app-build workflow template is missing — reinstall the plugin.', 'esipher' ) );
		}

		$files = array(
			'package.json'                     => $this->text( $this->package_json( $config, $include_ios ) ),
			'capacitor.config.json'            => $this->text( $this->capacitor_config( $config ) ),
			'www/index.html'                   => $this->text( $this->fallback_page( $config ) ),
			'resources/icon.png'               => $this->binary( $icon_png ),
			'resources/splash.png'             => $this->binary( $splash_png ),
			'resources/splash-dark.png'        => $this->binary( $splash_png ),
			'.github/workflows/build-app.yml'  => $this->text( $workflow ),
			'.gitignore'                       => $this->text( "node_modules/\nandroid/\nios/\n_out/\n_out_ios/\n*.log\n" ),
			'README.md'                        => $this->text( $this->readme( $config ) ),
		);

		// The iOS job in build-app.yml only runs when this marker file
		// is present (it's the one thing a GitHub Actions `if:` can
		// cheaply check). exportOptions.plist drives xcodebuild's
		// -exportArchive step.
		if ( $include_ios ) {
			$files['.esipher-ios.json']    = $this->text(
				wp_json_encode(
					array(
						'teamId'   => $config->apple_team_id,
						'bundleId' => $config->app_id,
					),
					JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES
				) . "\n"
			);
			$files['exportOptions.plist'] = $this->text( $this->export_options_plist( $config ) );
		}

		return $files;
	}

	/**
	 * @param string $raw
	 *
	 * @return array{content:string,is_base64:bool}
	 */
	private function text( $raw ) {
		return array( 'content' => $raw, 'is_base64' => false );
	}

	/**
	 * @param string $bytes
	 *
	 * @return array{content:string,is_base64:bool}
	 */
	private function binary( $bytes ) {
		return array( 'content' => base64_encode( $bytes ), 'is_base64' => true ); // phpcs:ignore WordPress.PHP.DiscouragedPHPFunctions.obfuscation_base64_encode -- packaging binary image bytes for the Git blobs API.
	}

	/**
	 * @param Mobile_App_Config $config
	 *
	 * @return string
	 */
	private function package_json( Mobile_App_Config $config, $include_ios = false ) {
		$dependencies = array(
			'@capacitor/core'    => self::CAP_VERSION,
			'@capacitor/android' => self::CAP_VERSION,
		);

		if ( $include_ios ) {
			$dependencies['@capacitor/ios'] = self::CAP_VERSION;
		}

		return wp_json_encode(
			array(
				'name'        => $config->package_slug(),
				'version'     => '1.0.0',
				'private'     => true,
				'description' => 'WebView wrapper app for ' . $config->site_url . ' — generated by Esipher.',
				'dependencies' => $dependencies,
				'devDependencies' => array(
					'@capacitor/cli'     => self::CAP_VERSION,
					'@capacitor/assets'  => self::ASSETS_VERSION,
				),
			),
			JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES
		) . "\n";
	}

	/**
	 * @param Mobile_App_Config $config
	 *
	 * @return string
	 */
	private function capacitor_config( Mobile_App_Config $config ) {
		$is_https = 0 === stripos( $config->site_url, 'https://' );

		$conf = array(
			'appId'   => $config->app_id,
			'appName' => $config->app_name,
			'webDir'  => 'www',
			'server'  => array(
				'url'            => $config->site_url,
				'cleartext'      => ! $is_https,
				'androidScheme'  => $is_https ? 'https' : 'http',
				'errorPath'      => 'index.html',
			),
			'android' => array(
				'backgroundColor' => $config->background_color,
			),
			'backgroundColor' => $config->background_color,
		);

		return wp_json_encode( $conf, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES ) . "\n";
	}

	/**
	 * Shown only when the device is offline or the site is unreachable
	 * (Capacitor's server.errorPath). Kept deliberately tiny and
	 * dependency-free.
	 *
	 * @param Mobile_App_Config $config
	 *
	 * @return string
	 */
	private function fallback_page( Mobile_App_Config $config ) {
		$template = ESIPHER_PLUGIN_DIR . 'templates/app-fallback.html.tpl';
		$html     = is_file( $template ) ? (string) file_get_contents( $template ) : ''; // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- reading this plugin's own bundled template.

		return strtr(
			$html,
			array(
				'{{NAME}}' => esc_html( $config->app_name ),
				'{{BG}}'   => esc_attr( $config->background_color ),
				'{{FG}}'   => esc_attr( $config->theme_color ),
			)
		);
	}

	/**
	 * @param Mobile_App_Config $config
	 *
	 * @return string
	 */
	private function readme( Mobile_App_Config $config ) {
		return implode(
			"\n",
			array(
				'# ' . $config->app_name . ' - mobile app',
				'',
				'A [Capacitor](https://capacitorjs.com/) WebView wrapper around',
				'<' . $config->site_url . '>, generated and maintained by the Esipher',
				'plugin. Don\'t edit these files by hand - change the app\'s settings under',
				'Esipher -> Mobile App in wp-admin and Esipher re-pushes them here.',
				'',
				'## Builds',
				'',
				'The bundled workflow (.github/workflows/build-app.yml) is run from the',
				'plugin. It outputs an "esipher-app" artifact (app-debug.apk to sideload,',
				'app-release.aab for the Google Play Console) and, when iOS is configured,',
				'an "esipher-app-ios" artifact (App.ipa for App Store Connect).',
				'',
				'Grab them from the newest green run under the repo\'s Actions tab, or via',
				'Esipher -> Mobile App -> Download latest build.',
				'',
				'## Signing',
				'',
				'The workflow signs with keys Esipher generated and stored as repo',
				'secrets. Keep them - the app stores permanently bind your app to them.',
				'',
				'Repo: ' . $config->full_name(),
				'',
			)
		);
	}

	/**
	 * The plist xcodebuild's -exportArchive step consumes. Automatic
	 * signing + the App Store Connect API key (passed on the xcodebuild
	 * command line by the workflow) means no certificate or provisioning
	 * profile has to be prepared by hand.
	 *
	 * @param Mobile_App_Config $config
	 *
	 * @return string
	 */
	private function export_options_plist( Mobile_App_Config $config ) {
		$team    = esc_html( $config->apple_team_id );
		$bundle  = esc_html( $config->app_id );
		$profile = esc_html( $config->ios_profile_name );

		return implode(
			"\n",
			array(
				'<?xml version="1.0" encoding="UTF-8"?>',
				'<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">',
				'<plist version="1.0">',
				'<dict>',
				'	<key>method</key>',
				'	<string>app-store</string>',
				'	<key>teamID</key>',
				'	<string>' . $team . '</string>',
				'	<key>signingStyle</key>',
				'	<string>manual</string>',
				'	<key>signingCertificate</key>',
				'	<string>Apple Distribution</string>',
				'	<key>provisioningProfiles</key>',
				'	<dict>',
				'		<key>' . $bundle . '</key>',
				'		<string>' . $profile . '</string>',
				'	</dict>',
				'	<key>destination</key>',
				'	<string>export</string>',
				'	<key>generateAppStoreInformation</key>',
				'	<false/>',
				'	<key>stripSwiftSymbols</key>',
				'	<true/>',
				'</dict>',
				'</plist>',
				'',
			)
		);
	}

	/**
	 * @param int $attachment_id
	 *
	 * @return string|\WP_Error Raw image bytes.
	 */
	private function load_icon_bytes( $attachment_id ) {
		$attachment_id = (int) $attachment_id;

		if ( $attachment_id <= 0 ) {
			return new \WP_Error( 'esipher_app_no_icon', __( 'Choose an app icon first (a square PNG, at least 512×512).', 'esipher' ) );
		}

		$path = get_attached_file( $attachment_id );

		if ( ! $path || ! is_file( $path ) ) {
			return new \WP_Error( 'esipher_app_icon_missing', __( 'The selected app icon file could not be found in the media library.', 'esipher' ) );
		}

		$bytes = file_get_contents( $path ); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_get_contents_file_get_contents -- reading a local media-library file chosen by the admin.

		if ( false === $bytes || '' === $bytes ) {
			return new \WP_Error( 'esipher_app_icon_unreadable', __( 'The selected app icon could not be read.', 'esipher' ) );
		}

		$size = @getimagesizefromstring( $bytes );

		if ( false === $size ) {
			return new \WP_Error( 'esipher_app_icon_not_image', __( 'The selected app icon is not a readable image.', 'esipher' ) );
		}

		if ( $size[0] < 512 || $size[1] < 512 ) {
			return new \WP_Error(
				'esipher_app_icon_small',
				sprintf(
					/* translators: 1: width, 2: height. */
					__( 'The app icon is %1$d×%2$d — it needs to be at least 512×512 (1024×1024 recommended).', 'esipher' ),
					$size[0],
					$size[1]
				)
			);
		}

		return $bytes;
	}

	/**
	 * Produce a square 1024×1024 PNG: the source scaled to fit and
	 * centred on a background-colour canvas (so a non-square source
	 * isn't stretched). Falls back to the raw bytes if GD is missing.
	 *
	 * @param string $bytes Source image bytes.
	 * @param string $bg     "#rrggbb".
	 *
	 * @return string PNG bytes.
	 */
	private function normalize_icon( $bytes, $bg ) {
		if ( ! function_exists( 'imagecreatefromstring' ) ) {
			return $bytes;
		}

		$src = @imagecreatefromstring( $bytes );

		if ( false === $src ) {
			return $bytes;
		}

		$out = $this->blank_canvas( self::ICON_SIZE, self::ICON_SIZE, $bg );

		$sw = imagesx( $src );
		$sh = imagesy( $src );
		$scale = min( self::ICON_SIZE / $sw, self::ICON_SIZE / $sh );
		$dw = (int) round( $sw * $scale );
		$dh = (int) round( $sh * $scale );
		$dx = (int) round( ( self::ICON_SIZE - $dw ) / 2 );
		$dy = (int) round( ( self::ICON_SIZE - $dh ) / 2 );

		imagecopyresampled( $out, $src, $dx, $dy, 0, 0, $dw, $dh, $sw, $sh );

		$png = $this->png_bytes( $out );

		imagedestroy( $src );
		imagedestroy( $out );

		return '' !== $png ? $png : $bytes;
	}

	/**
	 * A 2732×2732 splash: background colour with the icon centred at
	 * ~24% width.
	 *
	 * @param string $icon_png Normalised icon PNG bytes.
	 * @param string $bg        "#rrggbb".
	 *
	 * @return string PNG bytes.
	 */
	private function render_splash( $icon_png, $bg ) {
		if ( ! function_exists( 'imagecreatefromstring' ) ) {
			return $icon_png;
		}

		$canvas = $this->blank_canvas( self::SPLASH_SIZE, self::SPLASH_SIZE, $bg );
		$icon   = @imagecreatefromstring( $icon_png );

		if ( false !== $icon ) {
			$target = (int) round( self::SPLASH_SIZE * 0.24 );
			$pos    = (int) round( ( self::SPLASH_SIZE - $target ) / 2 );
			imagecopyresampled( $canvas, $icon, $pos, $pos, 0, 0, $target, $target, imagesx( $icon ), imagesy( $icon ) );
			imagedestroy( $icon );
		}

		$png = $this->png_bytes( $canvas );
		imagedestroy( $canvas );

		return '' !== $png ? $png : $icon_png;
	}

	/**
	 * @param int    $w
	 * @param int    $h
	 * @param string $hex "#rrggbb"
	 *
	 * @return \GdImage|resource
	 */
	private function blank_canvas( $w, $h, $hex ) {
		$img = imagecreatetruecolor( $w, $h );
		list( $r, $g, $b ) = $this->hex_to_rgb( $hex );
		imagefilledrectangle( $img, 0, 0, $w, $h, imagecolorallocate( $img, $r, $g, $b ) );

		return $img;
	}

	/**
	 * @param \GdImage|resource $img
	 *
	 * @return string PNG bytes, or '' on failure.
	 */
	private function png_bytes( $img ) {
		ob_start();
		$ok = imagepng( $img );
		$out = (string) ob_get_clean();

		return $ok ? $out : '';
	}

	/**
	 * @param string $hex "#rrggbb" (a leading # optional).
	 *
	 * @return array{0:int,1:int,2:int}
	 */
	private function hex_to_rgb( $hex ) {
		$hex = ltrim( (string) $hex, '#' );

		if ( 3 === strlen( $hex ) ) {
			$hex = $hex[0] . $hex[0] . $hex[1] . $hex[1] . $hex[2] . $hex[2];
		}

		if ( 6 !== strlen( $hex ) || ! ctype_xdigit( $hex ) ) {
			return array( 255, 255, 255 );
		}

		return array(
			hexdec( substr( $hex, 0, 2 ) ),
			hexdec( substr( $hex, 2, 2 ) ),
			hexdec( substr( $hex, 4, 2 ) ),
		);
	}
}