import * as assert from 'assert';
import * as vscode from 'vscode';
import { AIProvider, ChatOptions } from '../src/ai/providers/base';
import { aiFixReviewIssue } from '../src/fix/customFixEngine';
import type { ReviewIssueInput } from '../src/fix/fixPrompt';

class MockReviewFixProvider extends AIProvider {
  id = 'mock';
  name = 'mock';
  constructor(private responses: string[]) { super('key', 'url'); }
  async chat(_system: string, _user: string, _options: ChatOptions): Promise<string> {
    const next = this.responses.shift();
    return next ?? '{}';
  }
}

const options: ChatOptions = { model: 'mock', temperature: 0, maxTokens: 100, timeoutMs: 1000 };

function reviewDiag(message = 'bad code', line = 0): ReviewIssueInput {
  return { ruleId: 'custom:test-rule', line, message, suggestion: 'use GOOD instead' };
}

suite('Custom FixEngine Tests', () => {
  test('aiFixReviewIssue applies AI fix and converges after verify', async () => {
    const doc = await vscode.workspace.openTextDocument({
      content: 'const x = BAD;\n',
      language: 'javascript',
    });
    const provider = new MockReviewFixProvider([
      '{"originalText":"BAD","newText":"GOOD"}',
      '{"fixed":true}',
    ]);
    const result = await aiFixReviewIssue(doc, reviewDiag(), 3, provider, options, true);

    assert.strictEqual(result.success, true);
    assert.strictEqual(result.newText, 'const x = GOOD;\n');
    assert.strictEqual(result.appliedFixes.length, 1);
  });

  test('aiFixReviewIssue returns ai-match-failed when originalText not found', async () => {
    const doc = await vscode.workspace.openTextDocument({
      content: 'const x = BAD;\n',
      language: 'javascript',
    });
    const provider = new MockReviewFixProvider(['{"originalText":"NOPE","newText":"GOOD"}']);
    const result = await aiFixReviewIssue(doc, reviewDiag(), 3, provider, options, true);

    assert.strictEqual(result.success, false);
    assert.strictEqual(result.message, 'ai-match-failed');
  });

  test('aiFixReviewIssue retries until verify passes within maxIterations', async () => {
    const doc = await vscode.workspace.openTextDocument({
      content: 'const x = BAD;\n',
      language: 'javascript',
    });
    const provider = new MockReviewFixProvider([
      '{"originalText":"BAD","newText":"BAD2"}',
      '{"fixed":false,"reason":"still bad"}',
      '{"originalText":"BAD2","newText":"GOOD"}',
      '{"fixed":true}',
    ]);
    const result = await aiFixReviewIssue(doc, reviewDiag(), 3, provider, options, true);

    assert.strictEqual(result.success, true);
    assert.strictEqual(result.appliedFixes.length, 2);
    assert.strictEqual(result.newText, 'const x = GOOD;\n');
  });

  test('aiFixReviewIssue accepts last fix when verify never passes', async () => {
    const doc = await vscode.workspace.openTextDocument({
      content: 'const x = BAD;\n',
      language: 'javascript',
    });
    const provider = new MockReviewFixProvider([
      '{"originalText":"BAD","newText":"GOOD"}',
      '{"fixed":false,"reason":"still bad"}',
    ]);
    const result = await aiFixReviewIssue(doc, reviewDiag(), 1, provider, options, true);

    assert.strictEqual(result.success, true);
    assert.strictEqual(result.newText, 'const x = GOOD;\n');
    assert.strictEqual(result.appliedFixes.length, 1);
  });

  test('aiFixReviewIssue fails with ai-no-fix when AI provides empty fix', async () => {
    const doc = await vscode.workspace.openTextDocument({
      content: 'const x = BAD;\n',
      language: 'javascript',
    });
    const provider = new MockReviewFixProvider([
      '{"originalText":"","newText":""}',
      '{"originalText":"","newText":""}',
    ]);
    const result = await aiFixReviewIssue(doc, reviewDiag(), 3, provider, options, true);

    assert.strictEqual(result.success, false);
    assert.strictEqual(result.message, 'ai-no-fix');
  });
});