Initial commit

oAI/Services/WebSearchService.swift

@@ -0,0 +1,143 @@
+//
+//  WebSearchService.swift
+//  oAI
+//
+//  DuckDuckGo web search for non-OpenRouter providers
+//
+
+import Foundation
+import os
+
+struct SearchResult: Sendable {
+    let title: String
+    let url: String
+    let snippet: String
+}
+
+final class WebSearchService: Sendable {
+    nonisolated static let shared = WebSearchService()
+
+    private let session: URLSession
+
+    nonisolated private init() {
+        let config = URLSessionConfiguration.default
+        config.timeoutIntervalForRequest = 10
+        session = URLSession(configuration: config)
+    }
+
+    /// Search DuckDuckGo HTML interface (no API key needed)
+    nonisolated func search(query: String, maxResults: Int = 5) async -> [SearchResult] {
+        Log.search.info("Web search: \(query)")
+        guard let encoded = query.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed),
+              let url = URL(string: "https://html.duckduckgo.com/html/?q=\(encoded)")
+        else { return [] }
+
+        var request = URLRequest(url: url)
+        request.httpMethod = "GET"
+        request.setValue(
+            "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36",
+            forHTTPHeaderField: "User-Agent"
+        )
+
+        do {
+            let (data, _) = try await session.data(for: request)
+            guard let html = String(data: data, encoding: .utf8) else { return [] }
+            return parseResults(from: html, maxResults: maxResults)
+        } catch {
+            Log.search.error("Web search failed: \(error.localizedDescription)")
+            return []
+        }
+    }
+
+    /// Format search results as markdown for prompt injection
+    nonisolated func formatResults(_ results: [SearchResult], maxLength: Int = 2000) -> String {
+        if results.isEmpty { return "No search results found." }
+
+        var formatted = "**Web Search Results:**\n\n"
+
+        for (i, result) in results.enumerated() {
+            var entry = "\(i + 1). **\(result.title)**\n"
+            entry += "   URL: \(result.url)\n"
+            if !result.snippet.isEmpty {
+                entry += "   \(result.snippet)\n"
+            }
+            entry += "\n"
+
+            if formatted.count + entry.count > maxLength {
+                formatted += "... (\(results.count - i) more results truncated)\n"
+                break
+            }
+
+            formatted += entry
+        }
+
+        return formatted.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    // MARK: - HTML Parsing
+
+    private nonisolated func parseResults(from html: String, maxResults: Int) -> [SearchResult] {
+        var results: [SearchResult] = []
+
+        // Match result blocks: <div class="result results_links ...">
+        let blockPattern = #"<div class="result results_links.*?(?=<div class="result results_links|<div id="links")"#
+        guard let blockRegex = try? NSRegularExpression(pattern: blockPattern, options: .dotMatchesLineSeparators) else {
+            return []
+        }
+
+        let range = NSRange(html.startIndex..., in: html)
+        let blocks = blockRegex.matches(in: html, range: range)
+
+        for match in blocks.prefix(maxResults) {
+            guard let blockRange = Range(match.range, in: html) else { continue }
+            let block = String(html[blockRange])
+
+            // Extract title and URL from <a class="result__a" href="...">Title</a>
+            let titlePattern = #"<a[^>]*class="result__a"[^>]*href="([^"]+)"[^>]*>([^<]+)</a>"#
+            guard let titleRegex = try? NSRegularExpression(pattern: titlePattern),
+                  let titleMatch = titleRegex.firstMatch(in: block, range: NSRange(block.startIndex..., in: block)),
+                  let urlRange = Range(titleMatch.range(at: 1), in: block),
+                  let titleRange = Range(titleMatch.range(at: 2), in: block)
+            else { continue }
+
+            var resultURL = String(block[urlRange])
+            let title = decodeHTMLEntities(String(block[titleRange]).trimmingCharacters(in: .whitespaces))
+
+            // Extract snippet from <a class="result__snippet" ...>text</a>
+            let snippetPattern = #"<a[^>]*class="result__snippet"[^>]*>([^<]+)</a>"#
+            var snippet = ""
+            if let snippetRegex = try? NSRegularExpression(pattern: snippetPattern),
+               let snippetMatch = snippetRegex.firstMatch(in: block, range: NSRange(block.startIndex..., in: block)),
+               let snippetRange = Range(snippetMatch.range(at: 1), in: block) {
+                snippet = decodeHTMLEntities(String(block[snippetRange]).trimmingCharacters(in: .whitespaces))
+            }
+
+            // Decode DDG redirect URL
+            if resultURL.contains("uddg=") {
+                let uddgPattern = #"uddg=([^&]+)"#
+                if let uddgRegex = try? NSRegularExpression(pattern: uddgPattern),
+                   let uddgMatch = uddgRegex.firstMatch(in: resultURL, range: NSRange(resultURL.startIndex..., in: resultURL)),
+                   let uddgRange = Range(uddgMatch.range(at: 1), in: resultURL) {
+                    resultURL = String(resultURL[uddgRange]).removingPercentEncoding ?? resultURL
+                }
+            }
+
+            results.append(SearchResult(title: title, url: resultURL, snippet: snippet))
+        }
+
+        return results
+    }
+
+    private nonisolated func decodeHTMLEntities(_ string: String) -> String {
+        var result = string
+        let entities: [(String, String)] = [
+            ("&amp;", "&"), ("&lt;", "<"), ("&gt;", ">"),
+            ("&quot;", "\""), ("&#39;", "'"), ("&apos;", "'"),
+            ("&#x27;", "'"), ("&#x2F;", "/"), ("&nbsp;", " "),
+        ]
+        for (entity, char) in entities {
+            result = result.replacingOccurrences(of: entity, with: char)
+        }
+        return result
+    }
+}