const std = @import("std");
const types = @import("../weather/types.zig");

pub fn render(allocator: std.mem.Allocator, weather: types.WeatherData) ![]const u8 {
    var output = std.ArrayList(u8).init(allocator);
    errdefer output.deinit();

    try std.json.stringify(.{
        .current_condition = .{
            .temp_C = weather.current.temp_c,
            .temp_F = weather.current.temp_f,
            .weatherCode = weather.current.weather_code,
            .weatherDesc = .{.{ .value = weather.current.condition }},
            .humidity = weather.current.humidity,
            .windspeedKmph = weather.current.wind_kph,
            .winddirDegree = weather.current.wind_dir,
            .pressure = weather.current.pressure_mb,
            .precipMM = weather.current.precip_mm,
        },
        .weather = blk: {
            var forecast_array = std.ArrayList(struct {
                date: []const u8,
                maxtempC: f32,
                mintempC: f32,
                weatherCode: u16,
                weatherDesc: []const u8,
            }).init(allocator);
            defer forecast_array.deinit();

            for (weather.forecast) |day| {
                try forecast_array.append(.{
                    .date = day.date,
                    .maxtempC = day.max_temp_c,
                    .mintempC = day.min_temp_c,
                    .weatherCode = day.weather_code,
                    .weatherDesc = day.condition,
                });
            }

            break :blk try forecast_array.toOwnedSlice();
        },
    }, .{}, output.writer());

    return output.toOwnedSlice();
}

test "render json format" {
    const allocator = std.testing.allocator;

    const weather = types.WeatherData{
        .location = "London",
        .current = .{
            .temp_c = 15.0,
            .temp_f = 59.0,
            .condition = "Partly cloudy",
            .weather_code = 116,
            .humidity = 72,
            .wind_kph = 13.0,
            .wind_dir = "SW",
            .pressure_mb = 1013.0,
            .precip_mm = 0.0,
        },
        .forecast = &[_]types.ForecastDay{},
        .allocator = allocator,
    };

    const output = try render(allocator, weather);
    defer allocator.free(output);

    try std.testing.expect(output.len > 0);
    try std.testing.expect(std.mem.indexOf(u8, output, "temp_C") != null);
    try std.testing.expect(std.mem.indexOf(u8, output, "15") != null);
}