import Foundation
import UIKit

@MainActor
final class GitCallbackHandler {

    private let store: GitStore
    init(store: GitStore) { self.store = store }

    func handle(url: URL) {
        guard url.scheme == "padxcode", url.host == "git-callback" else { return }
        let params = parseQuery(url)
        store.pendingOperation = nil
        switch params["action"] ?? "" {
        case "repos":    handleRepos(params)
        case "status":   handleStatus(params)
        case "log":      handleLog(params)
        case "branches": handleBranches(params)
        case "checkout": NotificationCenter.default.post(name: .gitCheckoutCompleted, object: nil)
        case "commit":   store.fileStatuses = []; NotificationCenter.default.post(name: .gitCommitCompleted, object: nil)
        case "push":     NotificationCenter.default.post(name: .gitPushCompleted, object: nil)
        case "pull","fetch": NotificationCenter.default.post(name: .gitSyncCompleted, object: nil)
        case "merge":    NotificationCenter.default.post(name: .gitMergeCompleted, object: nil)
        case "write":    NotificationCenter.default.post(name: .gitWriteCompleted, object: nil)
        case "read":     handleRead(params)
        case "error":
            let msg = params["errorMessage"] ?? "Working Copy error."
            store.lastError = msg
            NotificationCenter.default.post(name: .gitOperationFailed, object: nil,
                                            userInfo: ["message": msg])
        default: break
        }
    }

    private func handleRepos(_ p: [String: String]) {
        guard let json = extractJSON(p),
              let repos = try? JSONDecoder().decode([GitRepository].self, from: json) else { return }
        store.repositories = repos
    }
    private func handleStatus(_ p: [String: String]) {
        guard let json = extractJSON(p),
              let statuses = try? JSONDecoder().decode([GitFileStatus].self, from: json) else { return }
        store.fileStatuses = statuses.filter { $0.status != "unchanged" }
    }
    private func handleLog(_ p: [String: String]) {
        guard let json = extractJSON(p),
              let commits = try? JSONDecoder().decode([GitCommit].self, from: json) else { return }
        store.commitLog = commits
    }
    private func handleBranches(_ p: [String: String]) {
        guard let json = extractJSON(p),
              let branches = try? JSONDecoder().decode([GitBranch].self, from: json) else { return }
        store.branches = branches
        if let current = branches.first(where: { !$0.isRemote }) { store.currentBranch = current.name }
    }
    private func handleRead(_ p: [String: String]) {
        guard let repo = p["repo"], let path = p["path"], let text = p["text"] else { return }
        let decoded = text.removingPercentEncoding ?? text
        NotificationCenter.default.post(name: .gitReadCompleted, object: nil,
                                        userInfo: ["repo": repo, "path": path, "content": decoded])
    }

    private func extractJSON(_ params: [String: String]) -> Data? {
        let raw = params[""] ?? params["text"] ?? ""
        return (raw.removingPercentEncoding ?? raw).data(using: .utf8)
    }
    private func parseQuery(_ url: URL) -> [String: String] {
        guard let items = URLComponents(url: url, resolvingAgainstBaseURL: false)?.queryItems
        else { return [:] }
        var result: [String: String] = [:]
        for item in items { result[item.name] = item.value ?? "" }
        return result
    }
}