import Foundation
import SaplingCore
import SaplingWorkspace
import XCTest

final class WorkspaceManagerTests: XCTestCase {
    private var temporaryRoots: [URL] = []

    override func tearDownWithError() throws {
        for url in temporaryRoots {
            try? FileManager.default.removeItem(at: url)
        }
        temporaryRoots = []
    }

    func testOpenWorkspaceBuildsFilesystemTree() async throws {
        let rootURL = try makeTemporaryWorkspace()
        try createDirectory("Notes", in: rootURL)
        try writeFile("Notes/Index.md", in: rootURL, contents: "# Notes")
        try writeFile("Notes/todo.txt", in: rootURL, contents: "todo")
        try createDirectory("Research/Archive", in: rootURL)
        try writeFile("Research/Archive/Paper.markdown", in: rootURL, contents: "# Paper")

        let workspace = try await LocalWorkspaceManager().openWorkspace(at: rootURL)

        XCTAssertEqual(workspace.rootURL, rootURL)
        XCTAssertEqual(workspace.items.map(\.displayName), ["Notes", "Research"])

        let notes = try XCTUnwrap(workspace.folder(named: "Notes"))
        XCTAssertEqual(notes.children.map(\.displayName), ["Index.md", "todo.txt"])
        XCTAssertEqual(try XCTUnwrap(notes.file(named: "Index.md")).kind, .markdown)
        XCTAssertEqual(try XCTUnwrap(notes.file(named: "todo.txt")).kind, .other)

        let archive = try XCTUnwrap(workspace.folder(named: "Research")?.folder(named: "Archive"))
        XCTAssertEqual(try XCTUnwrap(archive.file(named: "Paper.markdown")).kind, .markdown)
    }

    func testGitRepositoriesAreDetectedAsProjectsWithChildren() async throws {
        let rootURL = try makeTemporaryWorkspace()
        try createGitRepository("Sapling", in: rootURL)
        try writeFile("Sapling/README.md", in: rootURL, contents: "# Sapling")
        try createGitRepository("Research", in: rootURL)
        try writeFile("Research/Notes.md", in: rootURL, contents: "# Research")
        try createDirectory("Ordinary", in: rootURL)

        let workspace = try await LocalWorkspaceManager().openWorkspace(at: rootURL)

        XCTAssertEqual(workspace.items.map(\.displayName), ["Ordinary", "Research", "Sapling"])
        let research = try XCTUnwrap(workspace.project(named: "Research"))
        let sapling = try XCTUnwrap(workspace.project(named: "Sapling"))
        XCTAssertEqual(research.gitRepository.statusSummary, .unknown)
        XCTAssertEqual(sapling.gitRepository.rootURL.lastPathComponent, "Sapling")
        XCTAssertEqual(research.children.map(\.displayName), ["Notes.md"])
        XCTAssertNil(research.folder(named: ".git"))
    }

    func testHiddenFilesAndGitInternalsAreExcluded() async throws {
        let rootURL = try makeTemporaryWorkspace()
        try writeFile(".hidden.md", in: rootURL, contents: "# Hidden")
        try createGitRepository("Project", in: rootURL)
        try writeFile("Project/.git/config", in: rootURL, contents: "[core]")
        try writeFile("Project/Visible.md", in: rootURL, contents: "# Visible")

        let workspace = try await LocalWorkspaceManager().openWorkspace(at: rootURL)

        XCTAssertEqual(workspace.items.map(\.displayName), ["Project"])
        let project = try XCTUnwrap(workspace.project(named: "Project"))
        XCTAssertEqual(project.children.map(\.displayName), ["Visible.md"])
    }

    func testLargeFolderHierarchyScansWithinReasonableTime() async throws {
        let rootURL = try makeTemporaryWorkspace()
        for index in 0..<250 {
            let folderPath = String(format: "Folder-%03d/Nested", index)
            try createDirectory(folderPath, in: rootURL)
            try writeFile("\(folderPath)/Note-\(index).md", in: rootURL, contents: "# \(index)")
        }
        try createGitRepository("Project-000", in: rootURL)
        try writeFile("Project-000/README.md", in: rootURL, contents: "# Project")

        let start = Date()
        let workspace = try await LocalWorkspaceManager().openWorkspace(at: rootURL)
        let duration = Date().timeIntervalSince(start)

        XCTAssertEqual(workspace.items.count, 251)
        XCTAssertNotNil(workspace.project(named: "Project-000"))
        XCTAssertLessThan(duration, 2.0)
    }

    private func makeTemporaryWorkspace() throws -> URL {
        let url = FileManager.default.temporaryDirectory
            .appendingPathComponent("SaplingWorkspaceTests-\(UUID().uuidString)", isDirectory: true)
        try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
        temporaryRoots.append(url)
        return url
    }

    private func createDirectory(_ path: String, in rootURL: URL) throws {
        try FileManager.default.createDirectory(
            at: rootURL.appendingPathComponent(path, isDirectory: true),
            withIntermediateDirectories: true
        )
    }

    private func createGitRepository(_ path: String, in rootURL: URL) throws {
        try createDirectory(path, in: rootURL)
        try createDirectory("\(path)/.git", in: rootURL)
    }

    private func writeFile(_ path: String, in rootURL: URL, contents: String) throws {
        let url = rootURL.appendingPathComponent(path)
        try FileManager.default.createDirectory(
            at: url.deletingLastPathComponent(),
            withIntermediateDirectories: true
        )
        try contents.write(to: url, atomically: true, encoding: .utf8)
    }
}

private extension Workspace {
    func folder(named name: String) -> WorkspaceFolder? {
        items.compactMap { item -> WorkspaceFolder? in
            guard case .folder(let folder) = item, folder.name == name else { return nil }
            return folder
        }.first
    }

    func project(named name: String) -> Project? {
        items.compactMap { item -> Project? in
            guard case .project(let project) = item, project.name == name else { return nil }
            return project
        }.first
    }
}

private extension WorkspaceFolder {
    func folder(named name: String) -> WorkspaceFolder? {
        children.compactMap { item -> WorkspaceFolder? in
            guard case .folder(let folder) = item, folder.name == name else { return nil }
            return folder
        }.first
    }

    func file(named name: String) -> WorkspaceFile? {
        children.compactMap { item -> WorkspaceFile? in
            guard case .file(let file) = item, file.name == name else { return nil }
            return file
        }.first
    }
}

private extension Project {
    func folder(named name: String) -> WorkspaceFolder? {
        children.compactMap { item -> WorkspaceFolder? in
            guard case .folder(let folder) = item, folder.name == name else { return nil }
            return folder
        }.first
    }
}