import Foundation
import Testing
@testable import gitbay

private func makeClient() throws -> (GitbayClient, StubProtocol.Box) {
    let box = StubProtocol.box()
    let client = GitbayClient(
        instance: try GitbayInstance(url: "https://gitbay.org"),
        token: "test-token",
        session: box.session()
    )
    return (client, box)
}

private let emptyPage = #"{"protocol_version":1,"data":{"items":[]},"exit_code":0}"#
/// A refusal, not a 5xx: the client retries a 5xx once, which would
/// take the next stub and hide the failure.
private let refusal = #"{"protocol_version":1,"error":"denied","exit_code":4}"#

private func reads(_ stub: StubProtocol.Box, _ command: String) -> Int {
    stub.seen.count { $0.url.query()?.contains(command) == true }
}

/// Returning to a list from a pushed detail screen runs its `.task`
/// again. `loadIfNeeded()` reads the list only when nothing is shown yet,
/// so the pages and scroll position the user left are still there.
@MainActor
struct ListReturnTests {

    @Test func theIssueListLoadsOnce() async throws {
        let (client, stub) = try makeClient()
        stub.enqueue(.init(status: 200, json: emptyPage, match: "argv=issue&argv=list"))
        let model = IssueListViewModel(client: client, repoPath: "krz/gitbay")

        await model.loadIfNeeded()
        await model.loadIfNeeded()

        #expect(reads(stub, "argv=issue&argv=list") == 1)
    }

    @Test func theMRListLoadsOnce() async throws {
        let (client, stub) = try makeClient()
        stub.enqueue(.init(status: 200, json: emptyPage, match: "argv=mr&argv=list"))
        let model = MRListViewModel(client: client, repoPath: "krz/gitbay")

        await model.loadIfNeeded()
        await model.loadIfNeeded()

        #expect(reads(stub, "argv=mr&argv=list") == 1)
    }

    @Test func theBuildListLoadsOnce() async throws {
        let (client, stub) = try makeClient()
        stub.enqueue(.init(status: 200, json: emptyPage, match: "argv=build&argv=list"))
        let model = BuildListViewModel(client: client, repoPath: "krz/gitbay")

        await model.loadIfNeeded()
        await model.loadIfNeeded()

        #expect(reads(stub, "argv=build&argv=list") == 1)
    }

    @Test func aFailedLoadIsTriedAgainOnReturn() async throws {
        let (client, stub) = try makeClient()
        stub.enqueue(.init(status: 403, json: refusal, match: "argv=mr&argv=list"))
        stub.enqueue(.init(status: 200, json: emptyPage, match: "argv=mr&argv=list"))
        let model = MRListViewModel(client: client, repoPath: "krz/gitbay")

        await model.loadIfNeeded()
        await model.loadIfNeeded()

        #expect(reads(stub, "argv=mr&argv=list") == 2)
        guard case .empty = model.state else {
            Issue.record("expected .empty after the retry, got \(model.state)")
            return
        }
    }

    /// Pull-to-refresh still calls `load()`, which always reads.
    @Test func loadStillReloads() async throws {
        let (client, stub) = try makeClient()
        stub.enqueue(.init(status: 200, json: emptyPage, match: "argv=issue&argv=list"))
        stub.enqueue(.init(status: 200, json: emptyPage, match: "argv=issue&argv=list"))
        let model = IssueListViewModel(client: client, repoPath: "krz/gitbay")

        await model.loadIfNeeded()
        await model.load()

        #expect(reads(stub, "argv=issue&argv=list") == 2)
    }
}