const { describe, it } = require('node:test');
const assert = require('node:assert');
const { createBrowserContext, loadSource } = require('./helpers');
const vm = require('vm');

/**
 * Load Events + Extensions into a browser context.
 * Returns an object with Events, Extensions, and the sandbox.
 * Note: const declarations in vm contexts aren't sandbox properties,
 * so we extract them via vm.runInContext.
 */
function loadExtensions(overrides = {}) {
    const sandbox = createBrowserContext(overrides);
    loadSource(sandbox, 'events.js');
    loadSource(sandbox, 'extensions.js');
    // Extract const globals from the vm context
    const ctx = vm.createContext(sandbox); // idempotent on already-contextified sandbox
    return {
        Extensions: vm.runInContext('Extensions', ctx),
        Events: vm.runInContext('Events', ctx),
        sandbox,
    };
}

// ── Registration ─────────────────────────────

describe('Extensions.register', () => {
    it('registers an extension by id', () => {
        const ctx = loadExtensions();
        ctx.Extensions.register({ id: 'test-ext', init() {} });
        assert.ok(ctx.Extensions._registry.has('test-ext'));
    });

    it('rejects duplicate registrations', () => {
        const ctx = loadExtensions();
        ctx.Extensions.register({ id: 'dup', init() {} });
        ctx.Extensions.register({ id: 'dup', init() {} });
        assert.strictEqual(ctx.Extensions._registry.size, 1);
    });

    it('rejects registration without id', () => {
        const ctx = loadExtensions();
        ctx.Extensions.register({ init() {} });
        assert.strictEqual(ctx.Extensions._registry.size, 0);
    });
});

// ── Lifecycle ────────────────────────────────

describe('Extensions.initAll', () => {
    it('calls init on registered extensions', async () => {
        const ctx = loadExtensions();
        let initialized = false;
        ctx.Extensions.register({
            id: 'lifecycle-test',
            init(extCtx) { initialized = true; },
        });
        await ctx.Extensions.initAll();
        assert.ok(initialized);
    });

    it('marks extensions as active after init', async () => {
        const ctx = loadExtensions();
        ctx.Extensions.register({ id: 'active-test', init() {} });
        await ctx.Extensions.initAll();
        const entry = ctx.Extensions._registry.get('active-test');
        assert.strictEqual(entry.active, true);
    });

    it('survives init errors without crashing', async () => {
        const ctx = loadExtensions();
        ctx.Extensions.register({
            id: 'bad-ext',
            init() { throw new Error('init failed'); },
        });
        ctx.Extensions.register({
            id: 'good-ext',
            init() {},
        });
        await ctx.Extensions.initAll();
        assert.strictEqual(ctx.Extensions._registry.get('bad-ext').active, false);
        assert.strictEqual(ctx.Extensions._registry.get('good-ext').active, true);
    });
});

describe('Extensions.destroyAll', () => {
    it('calls destroy and deactivates extensions', async () => {
        const ctx = loadExtensions();
        let destroyed = false;
        ctx.Extensions.register({
            id: 'destroy-test',
            init() {},
            destroy() { destroyed = true; },
        });
        await ctx.Extensions.initAll();
        ctx.Extensions.destroyAll();
        assert.ok(destroyed);
        assert.strictEqual(ctx.Extensions._registry.get('destroy-test').active, false);
    });
});

// ── Context Object ──────────────────────────

describe('Extension context', () => {
    it('provides scoped events', async () => {
        const ctx = loadExtensions();
        let receivedPayload = null;
        ctx.Extensions.register({
            id: 'events-test',
            init(extCtx) {
                extCtx.events.on('test.event', (payload) => {
                    receivedPayload = payload;
                });
            },
        });
        await ctx.Extensions.initAll();
        ctx.Events.emit('test.event', { data: 42 }, { localOnly: true });
        assert.deepStrictEqual(receivedPayload, { data: 42 });
    });

    it('provides scoped storage', async () => {
        const ctx = loadExtensions();
        let storage = null;
        ctx.Extensions.register({
            id: 'storage-test',
            init(extCtx) {
                extCtx.storage.set('key1', { foo: 'bar' });
                storage = extCtx.storage.get('key1');
            },
        });
        await ctx.Extensions.initAll();
        assert.strictEqual(storage.foo, 'bar');
        // Verify namespacing
        assert.ok(ctx.sandbox.localStorage._data['ext::storage-test::key1']);
    });

    it('provides frozen settings from defaults', async () => {
        const ctx = loadExtensions();
        let settings = null;
        ctx.Extensions.register({
            id: 'settings-test',
            manifest: {
                settings: {
                    showInline: { type: 'boolean', default: true },
                    limit: { type: 'number', default: 100 },
                },
            },
            init(extCtx) { settings = extCtx.settings; },
        });
        await ctx.Extensions.initAll();
        assert.strictEqual(settings.showInline, true);
        assert.strictEqual(settings.limit, 100);
        // Frozen — assignment silently ignored in sloppy mode
        settings.showInline = false;
        assert.strictEqual(settings.showInline, true, 'frozen settings should not change');
    });
});

// ── Tool Registration ───────────────────────

describe('ctx.tools.handle', () => {
    it('registers a tool handler', async () => {
        const ctx = loadExtensions();
        ctx.Extensions.register({
            id: 'tool-test',
            init(extCtx) {
                extCtx.tools.handle('my_tool', async (args) => {
                    return { result: args.input * 2 };
                });
            },
        });
        await ctx.Extensions.initAll();
        assert.ok(ctx.Extensions._toolHandlers.has('my_tool'));
    });
});

// ── Tool Bridge ─────────────────────────────

describe('Tool bridge', () => {
    it('routes tool.call.* to registered handler and emits result', async () => {
        const ctx = loadExtensions();
        let resultEmitted = null;

        ctx.Extensions.register({
            id: 'bridge-test',
            init(extCtx) {
                extCtx.tools.handle('double', async (args) => {
                    return { value: args.n * 2 };
                });
            },
        });
        await ctx.Extensions.initAll();

        // Listen for the result event
        ctx.Events.on('tool.result.call-123', (payload) => {
            resultEmitted = payload;
        });

        // Simulate server sending tool.call
        ctx.Events.emit('tool.call.call-123', {
            call_id: 'call-123',
            tool: 'double',
            arguments: { n: 21 },
        }, { localOnly: true });

        // Allow async handler to complete
        await new Promise(r => setTimeout(r, 10));

        assert.ok(resultEmitted, 'result event should have been emitted');
        assert.strictEqual(resultEmitted.call_id, 'call-123');
        const parsed = JSON.parse(resultEmitted.result);
        assert.strictEqual(parsed.value, 42);
    });

    it('returns error for unknown tool', async () => {
        const ctx = loadExtensions();
        let resultEmitted = null;
        await ctx.Extensions.initAll();

        ctx.Events.on('tool.result.call-unknown', (payload) => {
            resultEmitted = payload;
        });

        ctx.Events.emit('tool.call.call-unknown', {
            call_id: 'call-unknown',
            tool: 'nonexistent_tool',
            arguments: {},
        }, { localOnly: true });

        await new Promise(r => setTimeout(r, 10));

        assert.ok(resultEmitted);
        assert.ok(resultEmitted.error, 'should have error field');
    });

    it('returns error when handler throws', async () => {
        const ctx = loadExtensions();
        let resultEmitted = null;

        ctx.Extensions.register({
            id: 'error-tool',
            init(extCtx) {
                extCtx.tools.handle('fail_tool', async () => {
                    throw new Error('something broke');
                });
            },
        });
        await ctx.Extensions.initAll();

        ctx.Events.on('tool.result.call-fail', (payload) => {
            resultEmitted = payload;
        });

        ctx.Events.emit('tool.call.call-fail', {
            call_id: 'call-fail',
            tool: 'fail_tool',
            arguments: {},
        }, { localOnly: true });

        await new Promise(r => setTimeout(r, 10));

        assert.ok(resultEmitted);
        assert.ok(resultEmitted.error);
        const parsed = JSON.parse(resultEmitted.error);
        assert.strictEqual(parsed.error, 'something broke');
    });
});

// ── Renderer Pipeline ───────────────────────

describe('Renderer pipeline', () => {
    it('registers and runs block renderers', async () => {
        const ctx = loadExtensions();
        let rendered = false;

        ctx.Extensions.register({
            id: 'renderer-test',
            init(extCtx) {
                extCtx.renderers.register('test-renderer', {
                    type: 'block',
                    pattern: 'mermaid',
                    render(lang, code, container) { rendered = true; },
                });
            },
        });
        await ctx.Extensions.initAll();

        const handled = ctx.Extensions.runBlockRenderers('mermaid', 'graph LR; A-->B', {});
        assert.ok(handled);
        assert.ok(rendered);
    });

    it('skips non-matching block renderers', async () => {
        const ctx = loadExtensions();
        ctx.Extensions.register({
            id: 'skip-test',
            init(extCtx) {
                extCtx.renderers.register('python-only', {
                    type: 'block',
                    pattern: 'python',
                    render() {},
                });
            },
        });
        await ctx.Extensions.initAll();

        const handled = ctx.Extensions.runBlockRenderers('javascript', 'code', {});
        assert.strictEqual(handled, false);
    });

    it('runs post renderers on container', async () => {
        const ctx = loadExtensions();
        let postRan = false;

        ctx.Extensions.register({
            id: 'post-test',
            init(extCtx) {
                extCtx.renderers.register('post-proc', {
                    type: 'post',
                    render(container) { postRan = true; },
                });
            },
        });
        await ctx.Extensions.initAll();

        ctx.Extensions.runPostRenderers({});
        assert.ok(postRan);
    });

    it('respects renderer priority ordering', async () => {
        const ctx = loadExtensions();
        const order = [];

        ctx.Extensions.register({
            id: 'priority-test',
            init(extCtx) {
                extCtx.renderers.register('low', {
                    type: 'post',
                    priority: 90,
                    render() { order.push('low'); },
                });
                extCtx.renderers.register('high', {
                    type: 'post',
                    priority: 10,
                    render() { order.push('high'); },
                });
            },
        });
        await ctx.Extensions.initAll();

        ctx.Extensions.runPostRenderers({});
        assert.deepStrictEqual(order, ['high', 'low']);
    });
});

// ── Debug ────────────────────────────────────

describe('Extensions.debug', () => {
    it('returns extension info and renderer count', async () => {
        const ctx = loadExtensions();
        ctx.Extensions.register({
            id: 'debug-ext',
            init(extCtx) {
                extCtx.renderers.register('r1', { type: 'post', render() {} });
            },
        });
        await ctx.Extensions.initAll();

        const info = ctx.Extensions.debug();
        assert.ok(info.extensions['debug-ext']);
        assert.strictEqual(info.extensions['debug-ext'].active, true);
        assert.strictEqual(info.rendererCount, 1);
    });
});

// ── Mermaid Extension ─────────────────────────────

describe('Mermaid renderer extension', () => {
    function loadWithMermaid() {
        const ctx = loadExtensions();
        // Load the mermaid extension script into the same VM context
        const fs = require('fs');
        const path = require('path');
        // The script lives alongside the test as a fixture, or in the repo root
        // For CI, we inline the registration to avoid path issues
        ctx.Extensions.register({
            id: 'mermaid-renderer',
            _mermaidReady: false,
            _mermaidLoading: null,
            _escapeHtml(str) {
                return str.replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
            },
            init(extCtx) {
                const self = this;
                extCtx.renderers.register('mermaid', {
                    type: 'block',
                    pattern: 'mermaid',
                    priority: 10,
                    render(lang, code, container) {
                        const id = 'mmd-test';
                        container.innerHTML = `
                            <div class="mermaid-block" data-mermaid-id="${id}">
                                <div class="mermaid-diagram" data-mermaid-src="${encodeURIComponent(code.trim())}">
                                    <div class="mermaid-loading">Rendering diagram…</div>
                                </div>
                                <details class="mermaid-source">
                                    <summary>View source</summary>
                                    <pre><code>${self._escapeHtml(code.trim())}</code></pre>
                                </details>
                            </div>
                        `;
                    }
                });
                extCtx.renderers.register('mermaid-post', {
                    type: 'post',
                    priority: 10,
                    render(container) {
                        // In test, just mark that post-render ran
                        container._mermaidPostRan = true;
                    }
                });
            },
            destroy() {}
        });
        return ctx;
    }

    it('registers both block and post renderers', async () => {
        const ctx = loadWithMermaid();
        await ctx.Extensions.initAll();
        const info = ctx.Extensions.debug();
        assert.strictEqual(info.extensions['mermaid-renderer'].active, true);
        const renderers = info.extensions['mermaid-renderer'].renderers;
        assert.strictEqual(renderers.length, 2);
        assert.strictEqual(renderers[0], 'mermaid');
        assert.strictEqual(renderers[1], 'mermaid-post');
        assert.strictEqual(info.rendererCount, 2);
    });

    it('block renderer matches mermaid language', async () => {
        const ctx = loadWithMermaid();
        await ctx.Extensions.initAll();

        const container = { innerHTML: '' };
        const handled = ctx.Extensions.runBlockRenderers('mermaid', 'graph LR; A-->B', container);
        assert.ok(handled);
        assert.ok(container.innerHTML.includes('mermaid-block'));
        assert.ok(container.innerHTML.includes('mermaid-diagram'));
        assert.ok(container.innerHTML.includes(encodeURIComponent('graph LR; A-->B')));
    });

    it('block renderer does not match other languages', async () => {
        const ctx = loadWithMermaid();
        await ctx.Extensions.initAll();

        const container = { innerHTML: '' };
        const handled = ctx.Extensions.runBlockRenderers('javascript', 'const x = 1;', container);
        assert.strictEqual(handled, false);
        assert.strictEqual(container.innerHTML, '');
    });

    it('block renderer includes source in details element', async () => {
        const ctx = loadWithMermaid();
        await ctx.Extensions.initAll();

        const container = { innerHTML: '' };
        ctx.Extensions.runBlockRenderers('mermaid', 'sequenceDiagram\n  A->>B: Hello', container);
        assert.ok(container.innerHTML.includes('mermaid-source'));
        assert.ok(container.innerHTML.includes('View source'));
        assert.ok(container.innerHTML.includes('sequenceDiagram'));
    });

    it('block renderer escapes HTML in source view', async () => {
        const ctx = loadWithMermaid();
        await ctx.Extensions.initAll();

        const container = { innerHTML: '' };
        ctx.Extensions.runBlockRenderers('mermaid', 'graph LR; A["<script>alert(1)</script>"]-->B', container);
        assert.ok(container.innerHTML.includes('&lt;script&gt;'));
        assert.ok(!container.innerHTML.includes('<script>alert'));
    });

    it('post renderer runs on container', async () => {
        const ctx = loadWithMermaid();
        await ctx.Extensions.initAll();

        const container = {};
        ctx.Extensions.runPostRenderers(container);
        assert.strictEqual(container._mermaidPostRan, true);
    });
});