import Foundation
import XCTest

@testable import Cepis

#if canImport(FoundationNetworking)
import FoundationNetworking
#endif

let seAddressJSON = """
    {"cep":"01001000","logradouro":"Praça da Sé","complemento":"lado ímpar",
     "unidade":"","bairro":"Sé","localidade":"São Paulo","uf":"SP",
     "estado":"São Paulo","regiao":"Sudeste","ibge":"3550308","gia":"1004",
     "ddd":"11","siafi":"7107"}
    """

/// The 404 for `25845000`: the CEP the DNE itself lists as Areal's first, and
/// which nonetheless does not exist.
let arealNotFoundJSON = """
    {"erro":"cep_nao_encontrado","mensagem":"CEP não existe na base do DNE",
     "faixa":{"localidade":"Areal","uf":"RJ","estado":"Rio de Janeiro","regiao":"Sudeste",
     "ibge":"3300225","cep_ini":"25845001","cep_fim":"25849899","ceps":118}}
    """

let csvHeader =
    "cep,logradouro,complemento,unidade,bairro,localidade,uf,estado,regiao,ibge,gia,ddd,siafi"

func csvBody(_ rows: [String]) -> String {
    ([csvHeader] + rows).joined(separator: "\n") + "\n"
}

class ServerBackedTestCase: XCTestCase {
    var server: TestHTTPServer!
    var client: Client!

    var routes: Router { server.router }

    override func setUpWithError() throws {
        try super.setUpWithError()
        server = try TestHTTPServer()
        client = Client(
            baseURL: server.baseURL,
            timeout: 5,
            backoffBase: 0.001,
            backoffMax: 0.01
        )
    }

    override func tearDown() {
        server?.stop()
        server = nil
        client = nil
        super.tearDown()
    }
}

final class NormalisationTests: XCTestCase {
    func testAcceptsMaskedAndUnmasked() throws {
        for value in ["01001000", "01001-000", " 01001-000 ", "01001.000"] {
            XCTAssertEqual(try normalizeCEP(value), "01001000")
        }
    }

    func testRejectsBadFormat() {
        for value in ["", "123", "0100100a", "010010000", "abcdefgh"] {
            XCTAssertThrowsError(try normalizeCEP(value)) { error in
                guard case CepisError.invalidCEP = error else {
                    return XCTFail("expected invalidCEP for \"\(value)\", got \(error)")
                }
            }
        }
    }

    func testInvalidCEPIsNotRetriable() {
        XCTAssertFalse(CepisError.invalidCEP("x").isRetriable)
        XCTAssertFalse(CepisError.cepNotFound(message: "x", faixa: nil).isRetriable)
        XCTAssertTrue(CepisError.networkError(message: "x").isRetriable)
    }
}

final class LookupTests: ServerBackedTestCase {
    func testSuccessfulLookup() async throws {
        routes.respond("/01001000", body: seAddressJSON)
        let address = try await client.lookup("01001-000")
        XCTAssertEqual(address.localidade, "São Paulo")
        XCTAssertEqual(address.logradouro, "Praça da Sé")
        XCTAssertEqual(address.uf, "SP")
        XCTAssertEqual(address.formattedCEP, "01001-000")
        XCTAssertNil(address.geo)
    }

    func testReadsTheCoordinateWhenPresent() async throws {
        routes.respond(
            "/01310100",
            body: """
                {"cep":"01310100","logradouro":"Avenida Paulista","localidade":"São Paulo",
                 "uf":"SP","geo":{"lat":-23.5,"lon":-46.6,"raio_m":120,
                 "precisao":"logradouro"}}
                """)
        let address = try await client.lookup("01310100")
        let geo = try XCTUnwrap(address.geo)
        XCTAssertEqual(geo.lat, -23.5, accuracy: 0.0001)
        XCTAssertEqual(geo.lon, -46.6, accuracy: 0.0001)
        XCTAssertEqual(geo.raioM, 120)
        XCTAssertTrue(geo.isPrecise)
    }

    func testMunicipalityCoordinateIsNotPrecise() async throws {
        routes.respond(
            "/01001000",
            body: """
                {"cep":"01001000","localidade":"São Paulo","geo":{"lat":-23.5,"lon":-46.6,
                 "raio_m":22000,"precisao":"localidade"}}
                """)
        let address = try await client.lookup("01001000")
        let geo = try XCTUnwrap(address.geo)
        XCTAssertFalse(geo.isPrecise)
        XCTAssertEqual(geo.raioM, 22000)
    }

    func testMalformedGeoDoesNotLoseTheAddress() async throws {
        routes.respond(
            "/01001000",
            body: #"{"cep":"01001000","localidade":"São Paulo","geo":{"lat":"not a number"}}"#)
        let address = try await client.lookup("01001000")
        XCTAssertNil(address.geo)
        XCTAssertEqual(address.localidade, "São Paulo")
    }

    func testNullGeoDoesNotLoseTheAddress() async throws {
        routes.respond(
            "/01001000", body: #"{"cep":"01001000","localidade":"São Paulo","geo":null}"#)
        let address = try await client.lookup("01001000")
        XCTAssertNil(address.geo)
        XCTAssertEqual(address.localidade, "São Paulo")
    }

    func testNewAPIFieldDoesNotBreak() async throws {
        routes.respond(
            "/01001000",
            body: #"{"cep":"01001000","localidade":"São Paulo","campo_do_futuro":"value"}"#)
        let address = try await client.lookup("01001000")
        XCTAssertEqual(address.localidade, "São Paulo")
    }

    func testNotFound() async throws {
        routes.respond(
            "/99999999", status: 404,
            body: #"{"erro":"cep_nao_encontrado","mensagem":"CEP não existe na base do DNE"}"#)
        do {
            _ = try await client.lookup("99999999")
            XCTFail("expected cepNotFound")
        } catch CepisError.cepNotFound(let message, let faixa) {
            XCTAssertTrue(message.contains("99999999"))
            XCTAssertNil(faixa)
        }
    }

    func testNotFoundIsNotRetried() async throws {
        routes.respond("/99999999", status: 404, body: #"{"erro":"cep_nao_encontrado"}"#)
        do {
            _ = try await client.lookup("99999999")
            XCTFail("expected cepNotFound")
        } catch CepisError.cepNotFound {
        }
        XCTAssertEqual(routes.count("/99999999"), 1)
    }

    func testInvalidCEPNeverLeavesTheMachine() async throws {
        do {
            _ = try await client.lookup("123")
            XCTFail("expected invalidCEP")
        } catch CepisError.invalidCEP {
        }
        XCTAssertEqual(routes.calls.count, 0)
    }

    func testAPI400BecomesInvalidCEP() async throws {
        routes.respond(
            "/00000000", status: 400,
            body: #"{"erro":"cep_invalido","mensagem":"rejected by the API"}"#)
        do {
            _ = try await client.lookup("00000000")
            XCTFail("expected invalidCEP")
        } catch CepisError.invalidCEP(let message) {
            XCTAssertEqual(message, "rejected by the API")
        }
    }

    func testResponseThatIsNotJSON() async throws {
        routes.respond("/01001000", body: "<html>captive portal</html>")
        do {
            _ = try await client.lookup("01001000")
            XCTFail("expected invalidResponse")
        } catch CepisError.invalidResponse {
        }
    }
}

final class NotFoundFaixaTests: ServerBackedTestCase {
    /// Serves `body` as the 404 for `cep` and returns the faixa that survived.
    private func faixaFromNotFound(_ body: String, cep: String = "25845000") async throws -> Faixa?
    {
        routes.respond("/\(cep)", status: 404, body: body)
        do {
            _ = try await client.lookup(cep)
            XCTFail("expected cepNotFound")
            return nil
        } catch CepisError.cepNotFound(_, let faixa) {
            return faixa
        }
    }

    func testNamesTheMunicipalityTheCEPWouldBelongTo() async throws {
        let decoded = try await faixaFromNotFound(arealNotFoundJSON)
        let faixa = try XCTUnwrap(decoded)
        XCTAssertEqual(faixa.localidade, "Areal")
        XCTAssertEqual(faixa.uf, "RJ")
        XCTAssertEqual(faixa.estado, "Rio de Janeiro")
        XCTAssertEqual(faixa.regiao, "Sudeste")
        XCTAssertEqual(faixa.ibge, "3300225")
        XCTAssertEqual(faixa.localidadeUF, "Areal/RJ")
    }

    /// The faixa decorates the 404; it must never promote it to a success.
    func testStillThrowsAndReturnsNoAddress() async throws {
        routes.respond("/25845000", status: 404, body: arealNotFoundJSON)
        do {
            let address = try await client.lookup("25845000")
            XCTFail("a faixa must not turn a not-found into \(address)")
        } catch CepisError.cepNotFound(let message, let faixa) {
            XCTAssertTrue(message.contains("25845000"))
            XCTAssertTrue(message.contains("does not exist"))
            XCTAssertNotNil(faixa)
        }
    }

    /// `cep_ini` is the first CEP that *exists*, not the DNE's published start
    /// — which for Areal is `25845000`, the very CEP that just failed.
    func testBoundsAreTheCEPsThatExistNotTheDNEStart() async throws {
        let decoded = try await faixaFromNotFound(arealNotFoundJSON)
        let faixa = try XCTUnwrap(decoded)
        XCTAssertEqual(faixa.cepIni, "25845001")
        XCTAssertEqual(faixa.cepFim, "25849899")
        XCTAssertNotEqual(faixa.cepIni, "25845000")
    }

    /// The pair is not a list: 118 CEPs across ~4,900 numbers.
    func testRangeIsSparse() async throws {
        let decoded = try await faixaFromNotFound(arealNotFoundJSON)
        let faixa = try XCTUnwrap(decoded)
        XCTAssertEqual(faixa.ceps, 118)

        let first = try XCTUnwrap(Int(faixa.cepIni))
        let last = try XCTUnwrap(Int(faixa.cepFim))
        let span = last - first + 1
        XCTAssertEqual(span, 4899)
        XCTAssertLessThan(faixa.ceps, span / 10)
    }

    func testAbsentWhenNoMunicipalityOwnsTheBand() async throws {
        let body = #"{"erro":"cep_nao_encontrado","mensagem":"CEP não existe na base do DNE"}"#
        let decoded = try await faixaFromNotFound(body)
        XCTAssertNil(decoded)
    }

    func testNullFaixaIsNil() async throws {
        let decoded = try await faixaFromNotFound(#"{"erro":"cep_nao_encontrado","faixa":null}"#)
        XCTAssertNil(decoded)
    }

    func testEmptyFaixaIsNil() async throws {
        let decoded = try await faixaFromNotFound(#"{"erro":"cep_nao_encontrado","faixa":{}}"#)
        XCTAssertNil(decoded)
    }

    func testFaixaWithoutAMunicipalityIsNil() async throws {
        for value in [#""""#, #""   ""#, "123", "null", "[]"] {
            let body = #"{"erro":"cep_nao_encontrado","faixa":{"localidade":\#(value),"uf":"RJ"}}"#
            let decoded = try await faixaFromNotFound(body)
            XCTAssertNil(decoded, "localidade \(value)")
        }
    }

    func testMalformedFaixaDoesNotBecomeADecodingFailure() async throws {
        let bodies = [
            #"{"erro":"cep_nao_encontrado","faixa":"Areal"}"#,
            #"{"erro":"cep_nao_encontrado","faixa":[{"localidade":"Areal"}]}"#,
            #"{"erro":"cep_nao_encontrado","faixa":{"localidade":{"nome":"Areal"}}}"#,
        ]
        for body in bodies {
            let decoded = try await faixaFromNotFound(body)
            XCTAssertNil(decoded, body)
        }
    }

    /// A 404 body that is not JSON at all is still a clean not-found, never an
    /// `invalidResponse`.
    func testNonJSONBodyStillYieldsNotFound() async throws {
        for body in ["<html>captive portal</html>", ""] {
            let decoded = try await faixaFromNotFound(body)
            XCTAssertNil(decoded, body)
        }
    }

    func testToleratesOddFieldTypesAroundTheMunicipality() async throws {
        let body = """
            {"erro":"cep_nao_encontrado","faixa":{"localidade":"Areal","uf":"RJ",
             "ibge":3300225,"cep_ini":"25845001","ceps":118.0}}
            """
        let decoded = try await faixaFromNotFound(body)
        let faixa = try XCTUnwrap(decoded)
        XCTAssertEqual(faixa.localidade, "Areal")
        XCTAssertEqual(faixa.ceps, 118)
        XCTAssertEqual(faixa.ibge, "")
        XCTAssertEqual(faixa.cepFim, "")
    }

    func testDescriptionMentionsTheMunicipality() async throws {
        routes.respond("/25845000", status: 404, body: arealNotFoundJSON)
        do {
            _ = try await client.lookup("25845000")
            XCTFail("expected cepNotFound")
        } catch let error as CepisError {
            XCTAssertTrue(error.description.contains("Areal/RJ"), error.description)
            XCTAssertEqual(error.errorDescription, error.description)
            XCTAssertEqual(error.faixa?.localidade, "Areal")
            // `message` stays what it always was, for callers matching on it.
            XCTAssertFalse(error.message.contains("Areal"))
        }
    }

    func testDescriptionWithoutAFaixaIsJustTheMessage() {
        let error = CepisError.cepNotFound(message: "CEP 99999999 does not exist", faixa: nil)
        XCTAssertEqual(error.description, error.message)
        XCTAssertEqual(error.errorDescription, error.message)
        XCTAssertNil(error.faixa)
    }

    func testFaixaAccessorIsNilForTheOtherCases() {
        XCTAssertNil(CepisError.invalidCEP("x").faixa)
        XCTAssertNil(CepisError.networkError(message: "x").faixa)
        XCTAssertNil(CepisError.serverError(message: "x", status: 500).faixa)
    }

    func testAFaixaIsStillNotRetriable() {
        let faixa = Faixa(localidade: "Areal", uf: "RJ")
        XCTAssertFalse(CepisError.cepNotFound(message: "x", faixa: faixa).isRetriable)
    }
}

final class RetryTests: ServerBackedTestCase {
    func testRetriesOn500ThenSucceeds() async throws {
        routes.respond(
            "/01001000",
            sequence: [
                StubResponse(status: 500, body: #"{"erro":"interno"}"#),
                StubResponse(status: 200, body: seAddressJSON),
            ])
        let address = try await client.lookup("01001000")
        XCTAssertEqual(address.localidade, "São Paulo")
        XCTAssertEqual(routes.count("/01001000"), 2)
    }

    func testExhaustsAttemptsThenThrows() async throws {
        routes.respond("/01001000", status: 503, body: #"{"erro":"interno"}"#)
        do {
            _ = try await client.lookup("01001000")
            XCTFail("expected serverError")
        } catch CepisError.serverError(_, let status) {
            XCTAssertEqual(status, 503)
        }
        XCTAssertEqual(routes.count("/01001000"), 3)
    }

    func testMaxAttemptsOneDisablesRetry() async throws {
        let single = Client(baseURL: server.baseURL, timeout: 5, maxAttempts: 1)
        routes.respond("/01001000", status: 500, body: "{}")
        do {
            _ = try await single.lookup("01001000")
            XCTFail("expected serverError")
        } catch CepisError.serverError {
        }
        XCTAssertEqual(routes.count("/01001000"), 1)
    }

    func test429BecomesRateLimitedWithRetryAfter() async throws {
        routes.respond("/01001000", status: 429, body: "{}", headers: ["Retry-After": "7"])
        do {
            _ = try await client.lookup("01001000")
            XCTFail("expected rateLimited")
        } catch CepisError.rateLimited(_, let retryAfter) {
            XCTAssertEqual(retryAfter, 7)
        }
    }

    func testRetryAfterHonoursTheCap() async throws {
        routes.respond("/01001000", status: 429, body: "{}", headers: ["Retry-After": "3600"])
        let started = Date()
        do {
            _ = try await client.lookup("01001000")
            XCTFail("expected rateLimited")
        } catch CepisError.rateLimited {
        }
        XCTAssertLessThan(Date().timeIntervalSince(started), 5)
    }

    func testRetryAfterAcceptsAnHTTPDate() throws {
        let formatter = DateFormatter()
        formatter.locale = Locale(identifier: "en_US_POSIX")
        formatter.timeZone = TimeZone(identifier: "GMT")
        formatter.dateFormat = "EEE, dd MMM yyyy HH:mm:ss zzz"
        let header = formatter.string(from: Date().addingTimeInterval(30))

        let seconds = try XCTUnwrap(Client.retryAfterSeconds(header))
        XCTAssertGreaterThan(seconds, 20)
        XCTAssertLessThan(seconds, 40)
    }

    func testRetryAfterInThePastIsClampedToZero() {
        XCTAssertEqual(Client.retryAfterSeconds("-5"), 0)
        XCTAssertNil(Client.retryAfterSeconds(nil))
        XCTAssertNil(Client.retryAfterSeconds("not a date"))
    }

    func testNetworkErrorWhenNothingListens() async throws {
        let unreachable = Client(
            baseURL: URL(string: "http://127.0.0.1:1")!,
            timeout: 1,
            maxAttempts: 2,
            backoffBase: 0.001,
            backoffMax: 0.01
        )
        do {
            _ = try await unreachable.lookup("01001000")
            XCTFail("expected networkError")
        } catch CepisError.networkError {
        }
    }

    func testTotalTimeoutBoundsTheWholeCall() async throws {
        let bounded = Client(
            baseURL: server.baseURL,
            timeout: 5,
            maxAttempts: 50,
            backoffBase: 0.05,
            backoffMax: 0.05,
            totalTimeout: 0.3
        )
        routes.respond("/01001000", status: 500, body: "{}")
        let started = Date()
        do {
            _ = try await bounded.lookup("01001000")
            XCTFail("expected serverError")
        } catch CepisError.serverError {
        }
        XCTAssertLessThan(Date().timeIntervalSince(started), 5)
        XCTAssertLessThan(routes.count("/01001000"), 50)
    }
}

final class BatchTests: ServerBackedTestCase {
    func testPreservesOrderAndMarksMissing() async throws {
        let body = csvBody([
            "01001000,Praça da Sé,lado ímpar,,Sé,São Paulo,SP,São Paulo,"
                + "Sudeste,3550308,1004,11,7107",
            "99999999,,,,,,,,,,,,",
            "20040020,Avenida Rio Branco,,,Centro,Rio de Janeiro,RJ,"
                + "Rio de Janeiro,Sudeste,3304557,,21,6001",
        ])
        routes.setHandler { _ in StubResponse(status: 200, body: body) }

        let result = try await client.lookupMany(["01001000", "99999999", "20040020"])
        XCTAssertEqual(result.count, 3)
        XCTAssertEqual(result[0]?.localidade, "São Paulo")
        XCTAssertNil(result[1])
        XCTAssertEqual(result[2]?.uf, "RJ")
        XCTAssertNil(result[0]?.geo)
    }

    func testFieldWithCommaIsParsed() async throws {
        let body = csvBody([
            #"01001000,"Rua Um, Dois",,,Centro,São Paulo,SP,São Paulo,Sudeste,1,,11,1"#
        ])
        routes.setHandler { _ in StubResponse(status: 200, body: body) }

        let result = try await client.lookupMany(["01001000"])
        XCTAssertEqual(result[0]?.logradouro, "Rua Um, Dois")
    }

    func testEscapedQuotesInAField() async throws {
        let body = csvBody([
            #"01001000,"Rua ""Dois"" Irmãos",,,Centro,São Paulo,SP,São Paulo,Sudeste,1,,11,1"#
        ])
        routes.setHandler { _ in StubResponse(status: 200, body: body) }

        let result = try await client.lookupMany(["01001000"])
        XCTAssertEqual(result[0]?.logradouro, #"Rua "Dois" Irmãos"#)
    }

    func testEmptyListMakesNoRequest() async throws {
        let result = try await client.lookupMany([])
        XCTAssertTrue(result.isEmpty)
        XCTAssertEqual(routes.calls.count, 0)
    }

    func testChunksAboveTheAPILimit() async throws {
        let ceps = (0..<501).map { String(format: "%08d", $0) }
        let first = csvBody(ceps[0..<500].map { "\($0),,,,,X,SP,São Paulo,Sudeste,1,,11,1" })
        let second = csvBody(ceps[500...].map { "\($0),,,,,X,SP,São Paulo,Sudeste,1,,11,1" })

        let served = NSLock()
        var count = 0
        routes.setHandler { _ in
            served.lock()
            defer { served.unlock() }
            count += 1
            return StubResponse(status: 200, body: count == 1 ? first : second)
        }

        let result = try await client.lookupMany(ceps)
        XCTAssertEqual(routes.count("/csv"), 2)
        XCTAssertEqual(result.count, 501)
        XCTAssertEqual(result[500]?.cep, "00000500")
    }

    func testTruncatedResponseDoesNotShift() async throws {
        let body = csvBody(["01001000,,,,,São Paulo,SP,São Paulo,Sudeste,1,,11,1"])
        routes.setHandler { _ in StubResponse(status: 200, body: body) }

        let result = try await client.lookupMany(["01001000", "20040020"])
        XCTAssertEqual(result.count, 2)
        XCTAssertEqual(result[0]?.localidade, "São Paulo")
        XCTAssertNil(result[1])
    }

    func testMalformedCEPBecomesNilRatherThanThrowing() async throws {
        let body = csvBody([
            "01001000,,,,,São Paulo,SP,São Paulo,Sudeste,1,,11,1",
            "abc,,,,,,,,,,,,",
        ])
        routes.setHandler { _ in StubResponse(status: 200, body: body) }

        let result = try await client.lookupMany(["01001000", "abc"])
        XCTAssertEqual(result.count, 2)
        XCTAssertNil(result[1])
    }
}

final class HealthTests: ServerBackedTestCase {
    func testReadsHealth() async throws {
        routes.respond(
            "/health",
            body: """
                {"status":"ok","dne":"26071","ceps":1596168,"geo":894489,
                 "base_gerada_em":"2026-07-24T03:48:28Z"}
                """)
        let health = try await client.health()
        XCTAssertTrue(health.ok)
        XCTAssertEqual(health.dne, "26071")
        XCTAssertEqual(health.ceps, 1_596_168)
        XCTAssertEqual(health.geo, 894_489)
        XCTAssertEqual(health.baseGeradaEm, "2026-07-24T03:48:28Z")
    }

    func testDegradedDoesNotThrow() async throws {
        routes.respond(
            "/health", status: 503,
            body: #"{"status":"degradado","dne":"","ceps":0,"geo":0}"#)
        let health = try await client.health()
        XCTAssertFalse(health.ok)
        XCTAssertEqual(health.status, "degradado")
        XCTAssertEqual(routes.count("/health"), 1)
    }
}

final class ConfigurationTests: XCTestCase {
    func testTrailingSlashIsNotDuplicated() {
        let client = Client(baseURL: URL(string: "http://example.test/")!)
        XCTAssertEqual(client.baseURL.absoluteString, "http://example.test")
    }

    func testUserAgentIdentifiesTheLibrary() {
        XCTAssertTrue(Client().userAgent.hasPrefix("cepis-swift/"))
        XCTAssertTrue(Client().userAgent.contains(Client.version))
    }

    func testDefaultBaseURL() {
        XCTAssertEqual(Client.defaultBaseURL.absoluteString, "https://cep.is")
        XCTAssertEqual(Client.maxBatch, 500)
    }

    func testFormattedCEPLeavesOddLengthsAlone() {
        XCTAssertEqual(Address(cep: "01001000").formattedCEP, "01001-000")
        XCTAssertEqual(Address(cep: "123").formattedCEP, "123")
    }
}

final class CSVTests: XCTestCase {
    func testParsesQuotedFieldsAndCRLF() {
        let rows = CSV.parse("a,b\r\n\"x,1\",\"y\"\"z\"\r\n")
        XCTAssertEqual(rows.count, 2)
        XCTAssertEqual(rows[0], ["a", "b"])
        XCTAssertEqual(rows[1], ["x,1", "y\"z"])
    }

    func testParsesLastLineWithoutNewline() {
        let rows = CSV.parse("a,b\n1,2")
        XCTAssertEqual(rows.count, 2)
        XCTAssertEqual(rows[1], ["1", "2"])
    }

    func testTrailingNewlineDoesNotProduceAnEmptyRow() {
        XCTAssertEqual(CSV.parse("a,b\n1,2\n").count, 2)
    }

    func testEmptyInput() {
        XCTAssertTrue(CSV.parse("").isEmpty)
    }
}