import Foundation
import Observation

/// `repo grep <owner/name> <query>` — server-side git grep, literal and
/// case-insensitive.
@Observable
@MainActor
final class GrepViewModel {

    nonisolated struct Match: Decodable, Sendable, Hashable, Identifiable {
        let path: String
        let line: Int
        let text: String
        var id: String { "\(path):\(line)" }
    }

    /// nil until the first search; distinct from an empty result.
    private(set) var state: LoadState<[Match]>?
    private(set) var lastQuery = ""

    private let client: GitbayClient
    let repoPath: String

    init(client: GitbayClient, repoPath: String) {
        self.client = client
        self.repoPath = repoPath
    }

    /// Matches grouped by file, in server order.
    var byFile: [(file: String, matches: [Match])] {
        guard let matches = state?.value else { return [] }
        var order: [String] = []
        var groups: [String: [Match]] = [:]
        for match in matches {
            if groups[match.path] == nil { order.append(match.path) }
            groups[match.path, default: []].append(match)
        }
        return order.map { ($0, groups[$0]!) }
    }

    func search(_ query: String) async {
        let trimmed = query.trimmingCharacters(in: .whitespaces)
        guard !trimmed.isEmpty else { return }
        lastQuery = trimmed
        state = .loading
        do {
            let matches = try await client.readList(
                ["repo", "grep", repoPath, trimmed], of: Match.self
            )
            state = matches.isEmpty
                ? .empty("No matches for \"\(trimmed)\".")
                : .loaded(matches)
        } catch {
            state = .from(error)
        }
    }
}