import Foundation
import Observation

/// `repo commit` — one commit with its patch, signature verdict and
/// checks.
nonisolated struct CommitDetail: Decodable, Sendable, Hashable {
    let path: String
    let sha: String
    let subject: String
    let message: String?
    let authorName: String
    let authorEmail: String
    let committerEmail: String?
    let date: Date
    let signature: Commit.Signature
    let checks: [Check]?
    /// The unified patch, parsed client-side exactly like `mr diff`.
    let diff: String

    enum CodingKeys: String, CodingKey {
        case path, sha, subject, message, date, signature, checks, diff
        case authorName = "author_name"
        case authorEmail = "author_email"
        case committerEmail = "committer_email"
    }

    var shortSHA: String { String(sha.prefix(10)) }

    nonisolated struct Check: Decodable, Sendable, Hashable, Identifiable {
        let context: String
        let state: String
        let url: String?
        var id: String { context }
    }
}

@Observable
@MainActor
final class CommitDetailViewModel {

    private(set) var state: LoadState<CommitDetail> = .loading
    private(set) var diff: UnifiedDiff?

    private let client: GitbayClient
    let repoPath: String
    let sha: String

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

    func load() async {
        do {
            let commit = try await client.read(
                ["repo", "commit", repoPath, sha], as: CommitDetail.self)
            diff = UnifiedDiff.parse(commit.diff)
            state = .loaded(commit)
        } catch {
            state = .from(error)
        }
    }
}