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.Projects;

public sealed class ProjectService(IDbContextFactory<ApplicationDbContext> contextFactory, HashService hashService) : IService
{
    public async ValueTask<Result> UpdateProjectStatusAsync(UpdateProjectStatusRequest request, Guid userId, CancellationToken cancellationToken = default)
    {
        try
        {
            using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var project = await context.Projects.FirstOrDefaultAsync(p => p.Id == request.ProjectId, cancellationToken);

            if (project == null)
                return Result.Fail("Project does not exist.");

            project.Status = request.Status;
            project.UpdatedBy = userId;
            project.UpdatedAt = DateTime.UtcNow;

            context.Projects.Update(project);

            var changedTotal = await context.Projects
                .Where(p => p.Id != request.ProjectId)
                .ExecuteUpdateAsync(f => f
                    .SetProperty(p => p.Status, request.Status)
                    .SetProperty(p => p.UpdatedBy, userId)
                    .SetProperty(p => p.UpdatedAt, DateTime.UtcNow), cancellationToken);

            return changedTotal > 0
                ? Result.Ok()
                : Result.Fail("Failed to update project");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

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

            var projects = await context.Projects.AsNoTracking().OrderByDescending(p => p.CreatedAt)
                .Skip((pagination.Page - 1) * pagination.PageSize)
                .Take(pagination.PageSize)
                .ToListAsync(cancellationToken);

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

    public async ValueTask<Result<Project>> GetProjectByIdAsync(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 project = await context.Projects.AsNoTracking().FirstOrDefaultAsync(p => p.Id == decodeResult.Value, cancellationToken);

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

    public async ValueTask<Result<Domain.Models.Activity[]>> GetActivitiesAsync(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 activities = await context.Activities.AsNoTracking()
                .Where(a => a.ProjectId == decodeResult.Value)
                .OrderByDescending(a => a.CreatedAt)
                .ToListAsync(cancellationToken);

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

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

            if (await context.Projects.AnyAsync(p => p.Name == request.Name && p.Sector == request.Sector && p.ProjectType == request.ProjectType, cancellationToken))
                return Result.Fail("A similarly named project exists of the same project type and sector");

            if (!await context.Programmes.AnyAsync(p => p.Id == request.ProgrammeId, cancellationToken))
                return Result.Fail($"Programme does not exist.");

            context.Projects.Add(new Domain.Entities.Project
            {
                ProgrammeId = request.ProgrammeId,
                Name = request.Name,
                Description = request.Description,
                Sector = request.Sector,
                ProjectType = request.ProjectType,
                Status = ApprovalStatus.Pending,
                CreatedBy = userId,
                CreatedAt = DateTime.UtcNow
            });

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

    public async ValueTask<Result> CreateActivityAsync(CreateActivityRequest 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 does not exist.");

            if (request.MilestoneId.HasValue)
                if (!await context.Milestones.AnyAsync(m => m.Id == request.MilestoneId.Value, cancellationToken))
                    return Result.Fail($"Milestone does not exist.");

            context.Activities.Add(new Domain.Entities.Activity
            {
                ProjectId = request.ProjectId,
                MilestoneId = request.MilestoneId,
                Category = request.Category,
                Amount = request.Amount,
                Title = request.Title,
                Description = request.Description,
                PerformedAt = request.PerformedAt,
                Status = ApprovalStatus.Pending,
                CreatedBy = userId,
                CreatedAt = DateTime.UtcNow
            });

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