import { spawn } from 'child_process';
import { resolve } from 'path';
import { normalizePath } from 'vite';
import picomatch from 'picomatch';

// Build queue to prevent overlapping builds
class BuildQueue {
    constructor() {
        this.queue = [];
        this.pending = false;
    }

    enqueue(buildFn) {
        return new Promise((resolve, reject) => {
            this.queue.push({ buildFn, resolve, reject });
            this.process();
        });
    }

    async process() {
        if (this.pending || this.queue.length === 0) return;

        this.pending = true;
        const { buildFn, resolve, reject } = this.queue.shift();

        try {
            await buildFn();
            resolve();
        } catch (error) {
            reject(error);
        } finally {
            this.pending = false;
            this.process();
        }
    }
}

const buildQueue = new BuildQueue();

export default function hotReloadPlugin(options = {}) {
    const config = {
        // Files to watch for changes
        watchFiles: [
            "./site/**/*.blade.php",
            "./site/**/*.md",
            "./site/**/*.html",
            "./config/**/*.php",
            "./app/**/*.php",
            "./zap.yml"
        ],

        // Files to ignore
        ignoreFiles: [
            'node_modules/**',
            'build_local/**',
            '.git/**',
            'vendor/**'
        ],

        // Build command
        buildCommand: 'php zap build',

        // Delay before refresh (ms)
        refreshDelay: 100,

        // Always do full page reload
        always: true,

        // Override with user options
        ...options
    };

    function runSiteBuild() {
        return new Promise((resolve, reject) => {
            const [command, ...args] = config.buildCommand.split(' ');

            const build = spawn(command, args, {
                stdio: 'inherit',
                shell: true
            });

            build.on('exit', (code) => {
                if (code === 0) resolve();
                else reject(new Error(`Build failed with code ${code}`));
            });
        });
    }

    return {
        name: 'static-site-hot-reload',

        config() {
            return {
                server: {
                    watch: {
                        disableGlobbing: false,
                        ignored: config.ignoreFiles.map(pattern =>
                            resolve(process.cwd(), pattern)
                        ).map(normalizePath)
                    }
                }
            };
        },

        configureServer(server) {
            // Normalize file paths
            const watchFiles = config.watchFiles.map(pattern =>
                resolve(process.cwd(), pattern)
            ).map(normalizePath);

            const shouldReload = picomatch(watchFiles);

            // Add files to Vite's watcher
            server.watcher.add(watchFiles);

            const handleFileChange = async (filePath) => {
                if (!shouldReload(filePath)) return;

                const start = performance.now();

                try {
                    // Queue the build to prevent overlaps
                    await buildQueue.enqueue(() => runSiteBuild());

                    const duration = Math.round(performance.now() - start);

                    // Delay the refresh
                    setTimeout(() => {
                        server.config.logger.info(
                            `full reload for ${filePath} - build: ${duration}ms`,
                            { timestamp: true, clear: true }
                        );

                        // Send full reload command
                        server.ws.send({
                            type: 'full-reload',
                            path: config.always ? '*' : filePath
                        });
                    }, config.refreshDelay);

                } catch (error) {
                    server.config.logger.error(`Build failed: ${error.message}`);
                }
            };

            // Listen for file changes
            server.watcher.on('add', handleFileChange);
            server.watcher.on('change', handleFileChange);

            // Initial build
            runSiteBuild().then(() => {
                server.config.logger.info('Initial build completed');
            }).catch((error) => {
                server.config.logger.error(`Initial build failed: ${error.message}`);
            });
        },

        // Handle hot updates
        handleHotUpdate({ file }) {
            const watchFiles = config.watchFiles.map(pattern =>
                resolve(process.cwd(), pattern)
            ).map(normalizePath);

            const shouldReload = picomatch(watchFiles);

            if (shouldReload(file)) {
                // Return empty array to prevent HMR, we'll do full reload instead
                return [];
            }

            // Let Vite handle other files normally
            return undefined;
        }
    };
}