using PostFundManagement.Application.Shared;
using PostFundManagement.Domain;
using PostFundManagement.Domain.Abstractions;
using PostFundManagement.Domain.Extensions;
using PostFundManagement.Domain.Models;
using PostFundManagement.Infrastructure.Database;

namespace PostFundManagement.Application.Services.Evidence;

public sealed class EvidenceService(IDbContextFactory<ApplicationDbContext> contextFactory, HashService hashService, 
    [FromKeyedServices(Constants.EvidenceBucketName)] IS3Service s3Service) : IService
{
    public async ValueTask<Result> UploadEvidenceFileAsync(Guid userId, IFormCollection form, IFormFile file, CancellationToken cancellationToken = default)
    {
        try
        {   
            _ = long.TryParse(form["projectId"], out var projectId);
            _ = long.TryParse(form["milestoneId"], out var milestoneId);
            _ = long.TryParse(form["indicatorId"], out var indicatorId);
            _ = long.TryParse(form["activityId"], out var activityId);
            _ = Enum.TryParse<EvidenceType>(form["type"], out var type);

            using var stream = file.OpenReadStream();

            var uploadResult = await s3Service.UploadFileAsync(file.FileName, stream, file.ContentType, cancellationToken);

            if (uploadResult.IsFailed)
                return Result.Fail(uploadResult.Errors.FirstOrDefault()?.Message ?? "File upload failed.");

            var documentUrl = uploadResult.Value;

            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var evidence = new Domain.Entities.Evidence
            {
                ProjectId = projectId,
                MilestoneId = milestoneId,
                IndicatorId = indicatorId,
                ActivityId = activityId,
                CreatedBy = userId,
                CreatedAt = DateTime.UtcNow,
                Version = 1,
                Type = type,
                DocumentUrl = documentUrl,
                Status = ApprovalStatus.Pending
            };

            context.Evidences.Add(evidence);

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail("Evidence upload failed");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> RecordIndicatorActualAmountAsync(string indicatorIdHash, decimal amount, Guid userId, CancellationToken cancellationToken = default)
    {
        try
        {   
            var decodeResult = hashService.DecodeLongIdHash(indicatorIdHash);

            if (decodeResult.IsFailed)
                return Result.Fail(decodeResult.Errors);

            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var totalUpdated = await context.Indicators.Where(i => i.Id == decodeResult.Value)
                .ExecuteUpdateAsync(f => f
                    .SetProperty(f => f.ActualAmount, amount)
                    .SetProperty(f => f.CreatedBy, userId), cancellationToken);

            return totalUpdated > 0
                ? Result.Ok()
                : Result.Fail("Failed to record actual amount");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<Milestone[]>> GetMilestonesByProjectIdAsync(string projectIdHash, CancellationToken cancellationToken = default)
    {
        try
        {
            var decodeResult = hashService.DecodeLongIdHash(projectIdHash);

            if (decodeResult.IsFailed)
                return Result.Fail(decodeResult.Errors);

            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var milestones = await context.Milestones.AsNoTracking()
                .Where(m => m.ProjectId == decodeResult.Value)
                .OrderBy(m => m.DueAt)
                .ToListAsync(cancellationToken);

            return Result.Ok(milestones?.Select(i => i.Map()).ToArray() ?? []);
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<Milestone[]>> GetMilestonesAsync(Pagination pagination, CancellationToken cancellationToken = default)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var milestones = await context.Milestones.AsNoTracking()
                .OrderByDescending(m => m.CreatedAt)
                .Skip((pagination.Page - 1) * pagination.PageSize)
                .Take(pagination.PageSize)
                .ToListAsync(cancellationToken);

            return Result.Ok(milestones?.Select(i => i.Map()).ToArray() ?? []);
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<Indicator[]>> GetIndicatorsAsync(Pagination pagination, CancellationToken cancellationToken = default)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var indicators = await context.Indicators.AsNoTracking()
                .OrderByDescending(i => i.CreatedAt)
                .Skip((pagination.Page - 1) * pagination.PageSize)
                .Take(pagination.PageSize)
                .ToListAsync(cancellationToken);

            return Result.Ok(indicators?.Select(i => i.Map()).ToArray() ?? []);
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<Domain.Models.Evidence[]>> GetEvidenceFilesAsync(Pagination pagination, CancellationToken cancellationToken = default)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var evidence = await context.Evidences.AsNoTracking()
                .OrderByDescending(e => e.CreatedAt)
                    .Skip((pagination.Page - 1) * pagination.PageSize)
                    .Take(pagination.PageSize)
                .ToListAsync(cancellationToken);

            return Result.Ok(evidence?.Select(i => i.Map()).ToArray() ?? []);
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> CreateMilestoneAsync(CreateMilestoneRequest request, Guid userId, CancellationToken cancellationToken = default)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            if (!await context.Projects.AnyAsync(p => p.Id == request.ProjectId, cancellationToken))
                return Result.Fail($"Project with ID {request.ProjectId} does not exist.");

            context.Milestones.Add(new Domain.Entities.Milestone
            {
                ProjectId = request.ProjectId,
                DueAt = request.DueAt,
                Name = request.Name,
                Priority = request.Priority,
                Status = ApprovalStatus.Pending,
                CreatedBy = userId,
                CreatedAt = DateTime.UtcNow
            });

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail("Failed to create the milestone");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> CreateIndicatorAsync(CreateIndicatorRequest request, Guid userId, CancellationToken cancellationToken = default)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            if (!await context.Users.AnyAsync(u => u.Id == userId && u.Status == ActivityStatus.Active, cancellationToken))
                return Result.Fail("Invalid user");

            if (!await context.Projects.AnyAsync(p => p.Id == request.ProjectId, cancellationToken))
                return Result.Fail($"Project with ID {request.ProjectId} does not exist.");

            context.Indicators.Add(new Domain.Entities.Indicator
            {
                ProjectId = request.ProjectId,
                Name = request.Name,
                UnitOfMeasure = request.UnitOfMeasure,
                BaselineAmount = request.BaselineAmount,
                TargetAmount = request.TargetAmount,
                ActualAmount = request.BaselineAmount,
                CreatedBy = userId,
                CreatedAt = DateTime.UtcNow
            });

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail("Failed to create the invite");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async Task<Result<Indicator>> GetIndicatorAsync(string indicatorId, CancellationToken cancellationToken)
    {
        try
        {
            var decodeResult = hashService.DecodeLongIdHash(indicatorId);

            if (decodeResult.IsFailed)
                return Result.Fail(decodeResult.Errors);

            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var indicator = await context.Indicators.AsNoTracking().FirstOrDefaultAsync(i => i.Id == decodeResult.Value, cancellationToken);

            return indicator is not null
                ? Result.Ok(indicator.Map())
                : Result.Fail("Failed to find specific indicator.");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async Task<Result<Milestone>> GetMilestoneAsync(string milestoneId, CancellationToken cancellationToken)
    {
        try
        {
            var decodeResult = hashService.DecodeLongIdHash(milestoneId);

            if (decodeResult.IsFailed)
                return Result.Fail(decodeResult.Errors);

            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var milestone = await context.Milestones.AsNoTracking().FirstOrDefaultAsync(m => m.Id == decodeResult.Value, cancellationToken);

            return milestone is not null
                ? Result.Ok(milestone.Map())
                : Result.Fail("Failed to get specific milestone");

        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<Domain.Models.Evidence>> GetEvidenceAsync(string evidenceId, CancellationToken cancellationToken = default)
    {
        try
        {
            var decodeResult = hashService.DecodeLongIdHash(evidenceId);

            if (decodeResult.IsFailed)
                return Result.Fail(decodeResult.Errors);

            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var evidence = await context.Evidences.AsNoTracking().FirstOrDefaultAsync(e => e.Id == decodeResult.Value, cancellationToken);

            return evidence is not null
                ? Result.Ok(evidence.Map())
                : Result.Fail("Failed to get a specific evidence record.");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }
}