using System.Text.Json;
using MAF1.Tools;
using MAF1.Utils;
using Microsoft.Agents.AI;
using Microsoft.Extensions.AI;

namespace MAF1.Agents.FileCity;

public static class FileCityAgent
{
    public static AIAgent Create(AgentFactory factory)
    {
        return factory.CreateAgent(
            name: "FileCityAgent",
            instructions:
            """
            你负责读取用户指定的本地文件，并从中提取有效城市名。
            必须先调用 ReadTextFile 读取文件，不要猜测文件内容。
            有效城市名：现实世界中真实存在的城市（如 成都、北京、Amsterdam）。
            忽略空行、注释、人名、水果、随意单词等不是城市的内容。
            只输出一个 JSON 对象，不要 Markdown，不要其它说明：
            {"hasValidCities": true, "cities": ["成都"], "reason": "说明"}
            若没有有效城市：{"hasValidCities": false, "cities": [], "reason": "原因"}
            cities 去重，保持文件中的出现顺序。
            """,
            tools: [AIFunctionFactory.Create(FileTools.ReadTextFile)]);
    }

    public static async Task<AgentStepResult> RunAsync(
        AIAgent agent,
        IReadOnlyDictionary<string, object?> inputs,
        CancellationToken cancellationToken = default)
    {
        string filePath = AgentInputs.ReadString(inputs, "filePath") ?? "Data/cities.txt";
        AgentResponse response = await agent.RunAsync(
            $"请读取这个文件并提取有效城市名：{filePath}",
            cancellationToken: cancellationToken);
        CityExtraction extraction = Parse(response.Text);
        return new AgentStepResult
        {
            Message = response.Text,
            Inputs = new Dictionary<string, object?> { ["filePath"] = filePath },
            Outputs = new Dictionary<string, object?>
            {
                ["hasValidCities"] = extraction.HasValidCities,
                ["cities"] = extraction.Cities,
                ["reason"] = extraction.Reason,
                ["raw"] = response.Text,
            },
        };
    }

    public static CityExtraction Parse(string text)
    {
        try
        {
            CityExtraction? result = JsonSerializer.Deserialize<CityExtraction>(
                JsonText.UnwrapObject(text),
                new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
            if (result is null)
            {
                return Invalid("无法解析文件 Agent 的输出。");
            }

            result.Cities = result.Cities
                .Where(city => !string.IsNullOrWhiteSpace(city))
                .Select(city => city.Trim())
                .Distinct(StringComparer.OrdinalIgnoreCase)
                .ToList();
            result.HasValidCities = result.HasValidCities && result.Cities.Count > 0;
            return result;
        }
        catch (JsonException ex)
        {
            return Invalid($"文件 Agent 没有返回合法 JSON：{ex.Message}");
        }
    }

    private static CityExtraction Invalid(string reason) =>
        new() { HasValidCities = false, Reason = reason };
}