import Foundation
import Testing
@testable import IrdAPI

@Suite struct PaginatorTests {
    @Test func cursorFollowsNextCursorUntilNil() async throws {
        let (client, http) = captureClient(script: [
            json(200, #"{"registrations":[{"id":"r1"}],"next_cursor":"c2"}"#),
            json(200, #"{"registrations":[{"id":"r2"}],"next_cursor":null}"#),
        ])
        let rows: [JSONValue] = try await Paginator.cursor(
            fetch: { (cursor: String?) in
                var q = [QueryItem("limit", "100")]
                if let cursor { q.append(QueryItem("cursor", cursor)) }
                return try await client.raw.request(method: .get, path: "/domains/registrations", query: q)
            },
            items: { $0["registrations"]?.arrayValue ?? [] },
            next: { $0["next_cursor"]?.stringValue })
        #expect(rows.map { $0["id"]?.stringValue } == ["r1", "r2"])
        #expect(http.trail == ["GET /domains/registrations?limit=100", "GET /domains/registrations?limit=100&cursor=c2"])
    }

    @Test func offsetWalksPagesUntilAShortOne() async throws {
        let (client, http) = captureClient(script: [
            json(200, #"{"pins":[{"id":"p1"},{"id":"p2"}],"total":3}"#),
            json(200, #"{"pins":[{"id":"p3"}],"total":3}"#),
        ])
        let rows: [JSONValue] = try await Paginator.offset(limit: 2,
            fetch: { limit, offset in
                try await client.raw.request(method: .get, path: "/ipfs/pins",
                                             query: [QueryItem("status", "pinned"), QueryItem("limit", String(limit)), QueryItem("offset", String(offset))])
            },
            items: { $0["pins"]?.arrayValue ?? [] })
        #expect(rows.count == 3)
        #expect(http.trail == ["GET /ipfs/pins?status=pinned&limit=2&offset=0", "GET /ipfs/pins?status=pinned&limit=2&offset=2"])
    }

    @Test func exactlyFullLastPageCostsOneEmptyRequest() async throws {
        let (client, http) = captureClient(script: [
            json(200, #"{"pins":[{"id":"p1"},{"id":"p2"}]}"#),
            json(200, #"{"pins":[]}"#),
        ])
        let rows: [JSONValue] = try await Paginator.offset(limit: 2,
            fetch: { limit, offset in
                try await client.raw.request(method: .get, path: "/ipfs/pins", query: [QueryItem("limit", String(limit)), QueryItem("offset", String(offset))])
            },
            items: { $0["pins"]?.arrayValue ?? [] })
        #expect(rows.count == 2)
        #expect(http.count == 2)
    }

    @Test func offsetDefaultsTo100And0() async throws {
        let (client, http) = captureClient(script: [json(200, #"{"pins":[]}"#)])
        let rows: [JSONValue] = try await Paginator.offset(
            fetch: { limit, offset in
                try await client.raw.request(method: .get, path: "/ipfs/pins", query: [QueryItem("limit", String(limit)), QueryItem("offset", String(offset))])
            },
            items: { $0["pins"]?.arrayValue ?? [] })
        #expect(rows.isEmpty)
        #expect(http.trail == ["GET /ipfs/pins?limit=100&offset=0"])
    }
}