namespace SimpleAdmin.Application;

/// <summary>
/// 实现入职合同预览和归档 DOCX 文件生成能力。
/// </summary>
public class OnboardingContractDocumentService : IOnboardingContractDocumentService
{
    private readonly SqlSugarScope _db;
    private readonly IFileService _fileService;

    public OnboardingContractDocumentService(IFileService fileService)
    {
        _db = DbContext.DB;
        _fileService = fileService;
    }

    /// <summary>
    /// 根据锁定的模板版本和任务变量快照生成已替换变量的合同 DOCX。
    /// </summary>
    public async Task<long> Generate(OnboardingGenerateContractInput input)
    {
        var contract = await _db.Queryable<ObTaskContract>().InSingleAsync(input.TaskContractId)
            ?? throw Oops.Bah("任务合同不存在");
        var task = await _db.Queryable<ObOnboardingTask>().InSingleAsync(contract.TaskId)
            ?? throw Oops.Bah("入职任务不存在");
        var statusAllowsGeneration = task.TaskStatus == OnboardingTaskStatus.PendingFill
                                     || task.TaskStatus == OnboardingTaskStatus.Rejected
                                     || task.TaskStatus == OnboardingTaskStatus.Reviewing
                                     || task.TaskStatus == OnboardingTaskStatus.Approved;
        if (!statusAllowsGeneration)
            throw Oops.Bah("当前任务状态不能生成合同");
        if (contract.GeneratedDocxFileId.HasValue)
            return contract.GeneratedDocxFileId.Value;

        var version = await _db.Queryable<ObContractTemplateVersion>().InSingleAsync(contract.TemplateVersionId)
            ?? throw Oops.Bah("合同版本不存在");
        var source = await _db.Queryable<SysFile>().InSingleAsync(version.SourceDocxFileId)
            ?? throw Oops.Bah("合同源文件不存在");
        var definitions = await _db.Queryable<ObTemplateVariable>()
            .Where(item => item.TemplateVersionId == version.Id)
            .ToListAsync();
        var variables = await _db.Queryable<ObTaskContractVariable>()
            .Where(item => item.TaskContractId == contract.Id)
            .ToListAsync();
        var missing = definitions
            .Where(item => item.Required)
            .FirstOrDefault(definition => string.IsNullOrWhiteSpace(
                variables.FirstOrDefault(variable => variable.VariableCode == definition.VariableCode)?.VariableValue));
        if (missing != null)
            throw Oops.Bah($"合同变量“{missing.VariableName}”尚未填写，暂时不能预览合同");

        var sourceResult = await _fileService.Download(new BaseIdInput { Id = source.Id })
            ?? throw Oops.Bah("无法读取合同源文件");
        await using var sourceStream = sourceResult.FileStream;
        using var sourceBytes = new MemoryStream();
        await sourceStream.CopyToAsync(sourceBytes);

        var rendered = DocxTemplateProcessor.Render(
            sourceBytes.ToArray(),
            variables.ToDictionary(
                item => item.VariableCode,
                item => item.VariableValue ?? string.Empty,
                StringComparer.OrdinalIgnoreCase));
        var generatedAt = DateTime.Now;
        // 在文件名中加入生成批次，避免手机系统把同名的新合同误认为历史下载文件。
        var name = $"{task.TaskNo}_{contract.ContractName}_{generatedAt:yyyyMMddHHmmssfff}.docx";
        var fileId = await _fileService.StoreGeneratedFile(
            SysDictConst.FILE_ENGINE_ALIYUN_OSS,
            name,
            rendered);

        contract.GeneratedDocxFileId = fileId;
        contract.GeneratedAt = generatedAt;
        contract.ContractStatus = task.TaskStatus == OnboardingTaskStatus.Approved
            ? TaskContractStatus.OfflinePendingSign
            : TaskContractStatus.PendingConfirm;
        await _db.Updateable(contract).ExecuteCommandAsync();
        return fileId;
    }
}