#include <mbgl/style/conversion/source.hpp>
#include <mbgl/style/conversion/coordinate.hpp>
#include <mbgl/style/conversion/geojson.hpp>
#include <mbgl/style/conversion/geojson_options.hpp>
#include <mbgl/style/conversion/source_options.hpp>
#include <mbgl/style/conversion/tileset.hpp>
#include <mbgl/style/conversion_impl.hpp>
#include <mbgl/style/sources/geojson_source.hpp>
#include <mbgl/style/sources/raster_source.hpp>
#include <mbgl/style/sources/raster_dem_source.hpp>
#include <mbgl/style/sources/vector_source.hpp>
#include <mbgl/style/sources/image_source.hpp>
#include <mbgl/style/sources/raster_array_source.hpp>
#include <mbgl/util/geo.hpp>

namespace mbgl {
namespace style {
namespace conversion {

namespace {
// A tile source can either specify a URL to TileJSON, or inline TileJSON.
std::optional<variant<std::string, Tileset>> convertURLOrTileset(const Convertible& value, Error& error) {
    auto urlVal = objectMember(value, "url");
    if (!urlVal) {
        std::optional<Tileset> tileset = convert<Tileset>(value, error);
        if (!tileset) {
            return std::nullopt;
        }
        return {std::move(*tileset)};
    }

    std::optional<std::string> url = toString(*urlVal);
    if (!url) {
        error.message = "source url must be a string";
        return std::nullopt;
    }

    return {std::move(*url)};
}

std::optional<std::unique_ptr<Source>> convertRasterSource(const std::string& id,
                                                           const Convertible& value,
                                                           Error& error) {
    std::optional<variant<std::string, Tileset>> urlOrTileset = convertURLOrTileset(value, error);
    if (!urlOrTileset) {
        return std::nullopt;
    }

    uint16_t tileSize = util::tileSize_I;
    auto tileSizeValue = objectMember(value, "tileSize");
    if (tileSizeValue) {
        std::optional<float> size = toNumber(*tileSizeValue);
        if (!size || *size < 0 || *size > std::numeric_limits<uint16_t>::max()) {
            error.message = "invalid tileSize";
            return std::nullopt;
        }
        tileSize = static_cast<uint16_t>(*size);
    }

    return {std::make_unique<RasterSource>(id, std::move(*urlOrTileset), tileSize)};
}

std::optional<std::unique_ptr<Source>> convertRasterDEMSource(const std::string& id,
                                                              const Convertible& value,
                                                              Error& error) {
    std::optional<variant<std::string, Tileset>> urlOrTileset = convertURLOrTileset(value, error);
    if (!urlOrTileset) {
        return std::nullopt;
    }

    uint16_t tileSize = util::tileSize_I;
    auto tileSizeValue = objectMember(value, "tileSize");
    if (tileSizeValue) {
        std::optional<float> size = toNumber(*tileSizeValue);
        if (!size || *size < 0 || *size > std::numeric_limits<uint16_t>::max()) {
            error.message = "invalid tileSize";
            return std::nullopt;
        }
        tileSize = static_cast<uint16_t>(*size);
    }

    /*
     TODO: Refactor TileJSON parsing responsibilities. Currently `Tileset` handles full TileJSON parsing with optional
           parameters. Since style.json can contain TileJSON parameter overrides or non-TileJSON spec parameters, a
           separate mechanism is needed. Ideally these two pathways share parsing logic.
    */
    auto options = convert<SourceOptions>(value, error);

    return {std::make_unique<RasterDEMSource>(id, std::move(*urlOrTileset), tileSize, options)};
}

std::optional<std::unique_ptr<Source>> convertVectorSource(const std::string& id,
                                                           const Convertible& value,
                                                           Error& error) {
    auto urlOrTileset = convertURLOrTileset(value, error);
    if (!urlOrTileset) {
        return std::nullopt;
    }
    const auto maxzoomValue = objectMember(value, "maxzoom");
    std::optional<float> maxzoom;
    if (maxzoomValue) {
        maxzoom = toNumber(*maxzoomValue);
        if (!maxzoom || *maxzoom < 0 || *maxzoom > std::numeric_limits<uint8_t>::max()) {
            error.message = "invalid maxzoom";
            return std::nullopt;
        }
    }
    const auto minzoomValue = objectMember(value, "minzoom");
    std::optional<float> minzoom;
    if (minzoomValue) {
        minzoom = toNumber(*minzoomValue);
        if (!minzoom || *minzoom < 0 || *minzoom > std::numeric_limits<uint8_t>::max()) {
            error.message = "invalid minzoom";
            return std::nullopt;
        }
    }
    const auto encodingValue = objectMember(value, "encoding");
    auto encoding = Tileset::VectorEncoding::Mapbox;
    if (encodingValue) {
        const auto encodingStr = toString(*encodingValue);
        if (encodingStr && encodingStr == "mvt") {
            encoding = Tileset::VectorEncoding::Mapbox;
        } else if (encodingStr && encodingStr == "mlt") {
            encoding = Tileset::VectorEncoding::MLT;
        } else {
            error.message = "invalid encoding";
            return std::nullopt;
        }
    }
    return {std::make_unique<VectorSource>(id, std::move(*urlOrTileset), maxzoom, minzoom, encoding)};
}

std::optional<std::unique_ptr<Source>> convertGeoJSONSource(const std::string& id,
                                                            const Convertible& value,
                                                            Error& error) {
    auto dataValue = objectMember(value, "data");
    if (!dataValue) {
        error.message = "GeoJSON source must have a data value";
        return std::nullopt;
    }

    Immutable<GeoJSONOptions> options = GeoJSONOptions::defaultOptions();
    if (std::optional<GeoJSONOptions> converted = convert<GeoJSONOptions>(value, error)) {
        options = makeMutable<GeoJSONOptions>(std::move(*converted));
    }

    auto result = std::make_unique<GeoJSONSource>(id, std::move(options));

    if (isObject(*dataValue)) {
        auto geoJSON = convert<GeoJSON>(*dataValue, error);
        if (!geoJSON) {
            return std::nullopt;
        }
        result->setGeoJSON(*geoJSON);
    } else if (toString(*dataValue)) {
        result->setURL(*toString(*dataValue));
    } else {
        error.message = "GeoJSON data must be a URL or an object";
        return std::nullopt;
    }

    return {std::move(result)};
}

std::optional<std::unique_ptr<Source>> convertImageSource(const std::string& id,
                                                          const Convertible& value,
                                                          Error& error) {
    auto urlValue = objectMember(value, "url");
    if (!urlValue) {
        error.message = "Image source must have a url value";
        return std::nullopt;
    }

    auto urlString = toString(*urlValue);
    if (!urlString) {
        error.message = "Image url must be a URL string";
        return std::nullopt;
    }

    auto coordinatesValue = objectMember(value, "coordinates");
    if (!coordinatesValue) {
        error.message = "Image source must have a coordinates values";
        return std::nullopt;
    }

    if (!isArray(*coordinatesValue) || arrayLength(*coordinatesValue) != 4) {
        error.message =
            "Image coordinates must be an array of four longitude latitude "
            "pairs";
        return std::nullopt;
    }

    std::array<LatLng, 4> coordinates;
    for (std::size_t i = 0; i < 4; i++) {
        auto latLng = conversion::convert<LatLng>(arrayMember(*coordinatesValue, i), error);
        if (!latLng) {
            return std::nullopt;
        }
        coordinates[i] = *latLng;
    }
    auto result = std::make_unique<ImageSource>(id, coordinates);
    result->setURL(*urlString);

    return {std::move(result)};
}

std::optional<std::unique_ptr<Source>> convertRasterArraySource(const std::string& id,
                                                                const Convertible& value,
                                                                Error& error) {
    if (const auto localFieldsValue = objectMember(value, "production-fields")) {
        if (!isArray(*localFieldsValue) || arrayLength(*localFieldsValue) < 2) {
            error.message = "raster-array production-fields must contain at least two entries";
            return std::nullopt;
        }
        std::vector<RasterArrayLocalFieldDescriptor> localFields;
        for (size_t index = 0; index < arrayLength(*localFieldsValue); ++index) {
            const auto entry = arrayMember(*localFieldsValue, index);
            const auto metadata = objectMember(entry, "metadata");
            const auto field = objectMember(entry, "field");
            if (!metadata || !field) {
                error.message = "raster-array production field requires metadata and field";
                return std::nullopt;
            }
            const auto metadataURL = toString(*metadata);
            const auto fieldURL = toString(*field);
            if (!metadataURL || !fieldURL) {
                error.message = "raster-array production field inputs must be strings";
                return std::nullopt;
            }
            localFields.push_back({*metadataURL, *fieldURL});
        }
        return {std::make_unique<RasterArraySource>(id, std::move(localFields))};
    }
    const auto fixture = objectMember(value, "fixture");
    const auto metadata = objectMember(value, "metadata");
    const auto field = objectMember(value, "field");
    if (!fixture || !metadata || !field) {
        error.message = "raster-array source requires fixture, metadata, and field";
        return std::nullopt;
    }
    const auto fixtureID = toString(*fixture);
    const auto metadataURL = toString(*metadata);
    const auto fieldURL = toString(*field);
    if (!fixtureID || !metadataURL || !fieldURL) {
        error.message = "raster-array fixture inputs must be strings";
        return std::nullopt;
    }
    const auto nextFixture = objectMember(value, "next-fixture");
    const auto nextMetadata = objectMember(value, "next-metadata");
    const auto nextField = objectMember(value, "next-field");
    if (static_cast<bool>(nextFixture) != static_cast<bool>(nextMetadata) ||
        static_cast<bool>(nextFixture) != static_cast<bool>(nextField)) {
        error.message = "raster-array next fixture requires next-fixture, next-metadata, and next-field";
        return std::nullopt;
    }
    std::vector<RasterArrayRuntimeFieldDescriptor> runtimeFields;
    if (const auto runtimeFieldsValue = objectMember(value, "runtime-fields")) {
        if (!isArray(*runtimeFieldsValue)) {
            error.message = "raster-array runtime-fields must be an array";
            return std::nullopt;
        }
        for (size_t index = 0; index < arrayLength(*runtimeFieldsValue); ++index) {
            const auto runtimeField = arrayMember(*runtimeFieldsValue, index);
            const auto runtimeFixture = objectMember(runtimeField, "fixture");
            const auto runtimeMetadata = objectMember(runtimeField, "metadata");
            const auto runtimeData = objectMember(runtimeField, "field");
            if (!runtimeFixture || !runtimeMetadata || !runtimeData) {
                error.message = "raster-array runtime field requires fixture, metadata, and field";
                return std::nullopt;
            }
            const auto runtimeFixtureID = toString(*runtimeFixture);
            const auto runtimeMetadataURL = toString(*runtimeMetadata);
            const auto runtimeFieldURL = toString(*runtimeData);
            if (!runtimeFixtureID || !runtimeMetadataURL || !runtimeFieldURL) {
                error.message = "raster-array runtime field inputs must be strings";
                return std::nullopt;
            }
            runtimeFields.push_back({*runtimeFixtureID, *runtimeMetadataURL, *runtimeFieldURL});
        }
    }
    if (!nextFixture) {
        return {std::make_unique<RasterArraySource>(
            id, *fixtureID, *metadataURL, *fieldURL, "", "", "", std::move(runtimeFields))};
    }
    const auto nextFixtureID = toString(*nextFixture);
    const auto nextMetadataURL = toString(*nextMetadata);
    const auto nextFieldURL = toString(*nextField);
    if (!nextFixtureID || !nextMetadataURL || !nextFieldURL) {
        error.message = "raster-array next fixture inputs must be strings";
        return std::nullopt;
    }
    return {std::make_unique<RasterArraySource>(id,
                                                *fixtureID,
                                                *metadataURL,
                                                *fieldURL,
                                                *nextFixtureID,
                                                *nextMetadataURL,
                                                *nextFieldURL,
                                                std::move(runtimeFields))};
}
} // namespace

std::optional<std::unique_ptr<Source>> Converter<std::unique_ptr<Source>>::operator()(const Convertible& value,
                                                                                      Error& error,
                                                                                      const std::string& id) const {
    if (!isObject(value)) {
        error.message = "source must be an object";
        return std::nullopt;
    }

    auto typeValue = objectMember(value, "type");
    if (!typeValue) {
        error.message = "source must have a type";
        return std::nullopt;
    }

    std::optional<std::string> type = toString(*typeValue);
    if (!type) {
        error.message = "source type must be a string";
        return std::nullopt;
    }
    const std::string& tname = type.value();
    if (tname == "raster") {
        return convertRasterSource(id, value, error);
    } else if (tname == "raster-dem") {
        return convertRasterDEMSource(id, value, error);
    } else if (tname == "vector") {
        return convertVectorSource(id, value, error);
    } else if (tname == "geojson") {
        return convertGeoJSONSource(id, value, error);
    } else if (tname == "image") {
        return convertImageSource(id, value, error);
    } else if (tname == "raster-array") {
        return convertRasterArraySource(id, value, error);
    } else {
        error.message = "invalid source type";
        return std::nullopt;
    }
}

} // namespace conversion
} // namespace style
} // namespace mbgl