using PowderCoating.Application.DTOs.Quote;
using PowderCoating.Application.Interfaces;
using PowderCoating.Core.Entities;

namespace PowderCoating.Application.Services;

/// <summary>
/// Converts quote/job data into persisted <see cref="JobItem"/>, <see cref="JobItemCoat"/>,
/// and <see cref="JobItemPrepService"/> entities.
///
/// Three source types are supported, each with a matching overload:
///   1. <see cref="CreateQuoteItemDto"/>  — quote wizard (new job from form data + fresh pricing result)
///   2. <see cref="QuoteItem"/>           — quote-to-job conversion (copies a saved quote line)
///   3. <see cref="JobItem"/>             — job duplication / template instantiation (copies an existing job line)
///
/// The private <see cref="JobItemSeed"/> / <see cref="JobItemCoatSeed"/> / <see cref="JobItemPrepServiceSeed"/>
/// intermediary classes exist solely to give all three overload paths a single <see cref="BuildJobItem"/>
/// construction site — avoiding subtle copy-paste drift where one overload forgets to copy a new field.
/// </summary>
public class JobItemAssemblyService : IJobItemAssemblyService
{
    /// <summary>
    /// Creates a <see cref="JobItem"/> from a quote wizard DTO and a pre-calculated pricing result.
    /// Used when creating a job directly from the job form or from an approved quote via the wizard.
    /// Pricing is passed in separately because it was already computed upstream (CalculateQuoteItemPriceAsync).
    /// </summary>
    public JobItem CreateJobItem(CreateQuoteItemDto source, int jobId, int companyId, QuoteItemPricingResult pricing, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);
        ArgumentNullException.ThrowIfNull(pricing);

        return BuildJobItem(
            new JobItemSeed
            {
                Description = source.Description,
                Quantity = source.Quantity,
                SurfaceAreaSqFt = source.SurfaceAreaSqFt,
                CatalogItemId = source.CatalogItemId,
                IsGenericItem = source.IsGenericItem,
                IsLaborItem = source.IsLaborItem,
                IsSalesItem = source.IsSalesItem,
                IsAiItem = source.IsAiItem,
                Sku = source.Sku,
                ManualUnitPrice = source.ManualUnitPrice,
                PowderCostOverride = source.PowderCostOverride,
                UnitPrice = pricing.UnitPrice,
                TotalPrice = pricing.TotalPrice,
                LaborCost = pricing.LaborCost,
                RequiresSandblasting = source.RequiresSandblasting,
                RequiresMasking = source.RequiresMasking,
                EstimatedMinutes = source.EstimatedMinutes,
                Notes = source.Notes,
                IncludePrepCost = source.IncludePrepCost,
                Complexity = source.Complexity,
                AiTags = source.AiTags,
                AiPredictionId = source.AiPredictionId
            },
            jobId,
            companyId,
            createdAtUtc);
    }

    /// <summary>
    /// Builds <see cref="JobItemCoat"/> records from the coat DTOs in the quote wizard form.
    /// PowderToOrder is recalculated server-side here (not trusted from the form) using surface area,
    /// quantity, coverage, and transfer efficiency — the wizard's displayed value is for UI only.
    /// </summary>
    public IReadOnlyList<JobItemCoat> CreateJobItemCoats(CreateQuoteItemDto source, int jobItemId, int companyId, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);

        return source.Coats?
            .OrderBy(c => c.Sequence)
            .Select(c => BuildJobItemCoat(
                new JobItemCoatSeed
                {
                    CoatName = c.CoatName,
                    Sequence = c.Sequence,
                    InventoryItemId = c.InventoryItemId,
                    ColorName = c.ColorName,
                    VendorId = c.VendorId,
                    ColorCode = c.ColorCode,
                    Finish = c.Finish,
                    CoverageSqFtPerLb = c.CoverageSqFtPerLb,
                    TransferEfficiency = c.TransferEfficiency,
                    PowderCostPerLb = c.PowderCostPerLb,
                    PowderToOrder = CalculatePowderToOrder(c.PowderToOrder, source.SurfaceAreaSqFt, source.Quantity, c.CoverageSqFtPerLb, c.TransferEfficiency),
                    Notes = c.Notes,
                    NoExtraLayerCharge = c.NoExtraLayerCharge
                },
                jobItemId,
                companyId,
                createdAtUtc))
            .ToList() ?? [];
    }

    /// <summary>
    /// Builds <see cref="JobItemPrepService"/> records (sandblasting, masking, etc.) from the
    /// quote wizard DTO. These are per-item prep steps with individual time estimates that feed
    /// labor cost calculations and shop floor instructions.
    /// </summary>
    public IReadOnlyList<JobItemPrepService> CreateJobItemPrepServices(CreateQuoteItemDto source, int jobItemId, int companyId, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);
        return BuildJobItemPrepServices(
            source.PrepServices?.Select(p => new JobItemPrepServiceSeed
            {
                PrepServiceId = p.PrepServiceId,
                EstimatedMinutes = p.EstimatedMinutes,
                BlastSetupId = p.BlastSetupId
            }),
            jobItemId,
            companyId,
            createdAtUtc);
    }

    /// <summary>
    /// Creates a <see cref="JobItem"/> by copying a saved <see cref="QuoteItem"/> during quote-to-job conversion.
    /// Prices are taken directly from the quote snapshot — no repricing occurs — so the job starts with
    /// exactly the amounts that were approved by the customer.
    /// The first coat's color/finish is promoted to the job item's top-level fields for quick display
    /// (details remain in the coat records).
    /// </summary>
    public JobItem CreateJobItem(QuoteItem source, int jobId, int companyId, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);

        var firstCoat = source.Coats?
            .OrderBy(c => c.Sequence)
            .FirstOrDefault();

        return BuildJobItem(
            new JobItemSeed
            {
                Description = source.Description,
                Quantity = source.Quantity,
                ColorName = firstCoat?.ColorName,
                ColorCode = firstCoat?.ColorCode,
                Finish = firstCoat?.Finish,
                SurfaceArea = source.SurfaceAreaSqFt,
                SurfaceAreaSqFt = source.SurfaceAreaSqFt,
                CatalogItemId = source.CatalogItemId,
                IsGenericItem = source.IsGenericItem,
                IsLaborItem = source.IsLaborItem,
                IsSalesItem = source.IsSalesItem,
                IsAiItem = source.IsAiItem,
                Sku = source.Sku,
                ManualUnitPrice = source.ManualUnitPrice,
                PowderCostOverride = source.PowderCostOverride,
                UnitPrice = source.UnitPrice,
                TotalPrice = source.TotalPrice,
                LaborCost = source.ItemLaborCost,
                RequiresSandblasting = source.RequiresSandblasting,
                RequiresMasking = source.RequiresMasking,
                EstimatedMinutes = source.EstimatedMinutes,
                Notes = source.Notes,
                IncludePrepCost = source.IncludePrepCost,
                Complexity = source.Complexity,
                AiTags = source.AiTags,
                AiPredictionId = source.AiPredictionId
            },
            jobId,
            companyId,
            createdAtUtc);
    }

    /// <summary>
    /// Builds <see cref="JobItemCoat"/> records from a saved <see cref="QuoteItem"/> during quote-to-job conversion.
    /// Coat appearance (color name, code, finish) is resolved from the linked <see cref="InventoryItem"/> if available,
    /// because the inventory record is the canonical source of truth for a product's appearance —
    /// the values typed into the quote form may be incomplete or informal.
    /// </summary>
    public IReadOnlyList<JobItemCoat> CreateJobItemCoats(QuoteItem source, int jobItemId, int companyId, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);

        return source.Coats?
            .OrderBy(c => c.Sequence)
            .Select(c =>
            {
                var appearance = ResolveCoatAppearance(c.ColorName, c.ColorCode, c.Finish, c.InventoryItem);
                return BuildJobItemCoat(
                    new JobItemCoatSeed
                    {
                        CoatName = c.CoatName,
                        Sequence = c.Sequence,
                        InventoryItemId = c.InventoryItemId,
                        ColorName = appearance.ColorName,
                        VendorId = c.VendorId,
                        ColorCode = appearance.ColorCode,
                        Finish = appearance.Finish,
                        CoverageSqFtPerLb = c.CoverageSqFtPerLb,
                        TransferEfficiency = c.TransferEfficiency,
                        PowderCostPerLb = c.PowderCostPerLb,
                        PowderToOrder = CalculatePowderToOrder(c.PowderToOrder, source.SurfaceAreaSqFt, source.Quantity, c.CoverageSqFtPerLb, c.TransferEfficiency),
                        Notes = c.Notes,
                        NoExtraLayerCharge = c.NoExtraLayerCharge
                    },
                    jobItemId,
                    companyId,
                    createdAtUtc);
            })
            .ToList() ?? [];
    }

    /// <summary>
    /// Copies prep service records from a <see cref="QuoteItem"/> to a new job item during quote-to-job conversion.
    /// </summary>
    public IReadOnlyList<JobItemPrepService> CreateJobItemPrepServices(QuoteItem source, int jobItemId, int companyId, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);
        return BuildJobItemPrepServices(
            source.PrepServices?.Select(p => new JobItemPrepServiceSeed
            {
                PrepServiceId = p.PrepServiceId,
                EstimatedMinutes = p.EstimatedMinutes,
                BlastSetupId = p.BlastSetupId
            }),
            jobItemId,
            companyId,
            createdAtUtc);
    }

    /// <summary>
    /// Creates a new <see cref="JobItem"/> by cloning an existing one — used for job templates
    /// and rework duplication where an existing job line is reused on a new job.
    /// Prices are copied as-is from the source; the job controller is responsible for repricing
    /// if operating costs have changed since the original job was created.
    /// </summary>
    public JobItem CreateJobItem(JobItem source, int jobId, int companyId, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);

        return BuildJobItem(
            new JobItemSeed
            {
                Description = source.Description,
                Quantity = source.Quantity,
                ColorName = source.ColorName,
                ColorCode = source.ColorCode,
                Finish = source.Finish,
                SurfaceArea = source.SurfaceArea,
                SurfaceAreaSqFt = source.SurfaceAreaSqFt,
                CatalogItemId = source.CatalogItemId,
                IsGenericItem = source.IsGenericItem,
                IsLaborItem = source.IsLaborItem,
                IsSalesItem = source.IsSalesItem,
                IsAiItem = source.IsAiItem,
                Sku = source.Sku,
                ManualUnitPrice = source.ManualUnitPrice,
                PowderCostOverride = source.PowderCostOverride,
                UnitPrice = source.UnitPrice,
                TotalPrice = source.TotalPrice,
                LaborCost = source.LaborCost,
                RequiresSandblasting = source.RequiresSandblasting,
                RequiresMasking = source.RequiresMasking,
                EstimatedMinutes = source.EstimatedMinutes,
                Notes = source.Notes,
                IncludePrepCost = source.IncludePrepCost,
                Complexity = source.Complexity,
                AiTags = source.AiTags,
                AiPredictionId = source.AiPredictionId
            },
            jobId,
            companyId,
            createdAtUtc);
    }

    /// <summary>
    /// Clones coat records from an existing <see cref="JobItem"/> onto a new job item.
    /// PowderToOrder is copied verbatim (not recalculated) because the original job's powder
    /// quantities may have been manually adjusted after initial calculation.
    /// </summary>
    public IReadOnlyList<JobItemCoat> CreateJobItemCoats(JobItem source, int jobItemId, int companyId, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);

        return source.Coats?
            .OrderBy(c => c.Sequence)
            .Select(c => BuildJobItemCoat(
                new JobItemCoatSeed
                {
                    CoatName = c.CoatName,
                    Sequence = c.Sequence,
                    InventoryItemId = c.InventoryItemId,
                    ColorName = c.ColorName,
                    VendorId = c.VendorId,
                    ColorCode = c.ColorCode,
                    Finish = c.Finish,
                    CoverageSqFtPerLb = c.CoverageSqFtPerLb,
                    TransferEfficiency = c.TransferEfficiency,
                    PowderCostPerLb = c.PowderCostPerLb,
                    PowderToOrder = c.PowderToOrder,
                    Notes = c.Notes,
                    NoExtraLayerCharge = c.NoExtraLayerCharge
                },
                jobItemId,
                companyId,
                createdAtUtc))
            .ToList() ?? [];
    }

    /// <summary>
    /// Clones prep service records from an existing <see cref="JobItem"/> onto a new job item.
    /// </summary>
    public IReadOnlyList<JobItemPrepService> CreateJobItemPrepServices(JobItem source, int jobItemId, int companyId, DateTime createdAtUtc)
    {
        ArgumentNullException.ThrowIfNull(source);
        return BuildJobItemPrepServices(
            source.PrepServices?.Select(p => new JobItemPrepServiceSeed
            {
                PrepServiceId = p.PrepServiceId,
                EstimatedMinutes = p.EstimatedMinutes,
                BlastSetupId = p.BlastSetupId
            }),
            jobItemId,
            companyId,
            createdAtUtc);
    }

    /// <summary>
    /// Single construction point for all <see cref="JobItem"/> creation paths.
    /// Centralised here so that adding a new field only requires one code change, not three.
    /// </summary>
    private static JobItem BuildJobItem(JobItemSeed seed, int jobId, int companyId, DateTime createdAtUtc)
    {
        return new JobItem
        {
            JobId = jobId,
            Description = seed.Description,
            Quantity = seed.Quantity,
            ColorName = seed.ColorName,
            ColorCode = seed.ColorCode,
            Finish = seed.Finish,
            SurfaceArea = seed.SurfaceArea,
            SurfaceAreaSqFt = seed.SurfaceAreaSqFt,
            CatalogItemId = seed.CatalogItemId,
            IsGenericItem = seed.IsGenericItem,
            IsLaborItem = seed.IsLaborItem,
            IsSalesItem = seed.IsSalesItem,
            IsAiItem = seed.IsAiItem,
            Sku = seed.Sku,
            ManualUnitPrice = seed.ManualUnitPrice,
            PowderCostOverride = seed.PowderCostOverride,
            UnitPrice = seed.UnitPrice,
            TotalPrice = seed.TotalPrice,
            LaborCost = seed.LaborCost,
            RequiresSandblasting = seed.RequiresSandblasting,
            RequiresMasking = seed.RequiresMasking,
            EstimatedMinutes = seed.EstimatedMinutes,
            Notes = seed.Notes,
            IncludePrepCost = seed.IncludePrepCost,
            Complexity = seed.Complexity,
            AiTags = seed.AiTags,
            AiPredictionId = seed.AiPredictionId,
            CompanyId = companyId,
            CreatedAt = createdAtUtc
        };
    }

    /// <summary>
    /// Single construction point for all <see cref="JobItemCoat"/> creation paths.
    /// </summary>
    private static JobItemCoat BuildJobItemCoat(JobItemCoatSeed seed, int jobItemId, int companyId, DateTime createdAtUtc)
    {
        return new JobItemCoat
        {
            JobItemId = jobItemId,
            CoatName = seed.CoatName,
            Sequence = seed.Sequence,
            InventoryItemId = seed.InventoryItemId,
            ColorName = seed.ColorName,
            VendorId = seed.VendorId,
            ColorCode = seed.ColorCode,
            Finish = seed.Finish,
            CoverageSqFtPerLb = seed.CoverageSqFtPerLb,
            TransferEfficiency = seed.TransferEfficiency,
            PowderCostPerLb = seed.PowderCostPerLb,
            PowderToOrder = seed.PowderToOrder,
            Notes = seed.Notes,
            NoExtraLayerCharge = seed.NoExtraLayerCharge,
            CompanyId = companyId,
            CreatedAt = createdAtUtc
        };
    }

    /// <summary>
    /// Single construction point for all <see cref="JobItemPrepService"/> creation paths.
    /// Returns an empty list (not null) when <paramref name="seeds"/> is null so callers
    /// can safely iterate without a null check.
    /// </summary>
    private static IReadOnlyList<JobItemPrepService> BuildJobItemPrepServices(IEnumerable<JobItemPrepServiceSeed>? seeds, int jobItemId, int companyId, DateTime createdAtUtc)
    {
        return seeds?
            .Select(seed => new JobItemPrepService
            {
                JobItemId = jobItemId,
                PrepServiceId = seed.PrepServiceId,
                EstimatedMinutes = seed.EstimatedMinutes,
                BlastSetupId = seed.BlastSetupId,
                CompanyId = companyId,
                CreatedAt = createdAtUtc
            })
            .ToList() ?? [];
    }

    /// <summary>
    /// Returns the pounds of powder needed to coat a batch, preferring the pre-stored value
    /// (which the user may have manually adjusted in the wizard) over a fresh recalculation.
    ///
    /// Formula: (surfaceAreaSqFt × quantity) ÷ (coverageSqFtPerLb × transferEfficiency)
    ///
    /// Industry defaults are applied when catalog data is missing:
    ///   - Coverage: 30 sqft/lb  (typical for standard powder at 2–3 mil DFT)
    ///   - Transfer efficiency: 65% (industry average for electrostatic spray)
    /// These are conservative defaults that slightly overestimate powder needed — intentional,
    /// so the shop doesn't run short on a job.
    /// </summary>
    private static decimal? CalculatePowderToOrder(decimal? storedPowderToOrder, decimal surfaceAreaSqFt, decimal quantity, decimal coverageSqFtPerLb, decimal transferEfficiency)
    {
        if (storedPowderToOrder.HasValue && storedPowderToOrder.Value > 0)
            return storedPowderToOrder;

        if (surfaceAreaSqFt <= 0)
            return null;

        var coverage = coverageSqFtPerLb > 0 ? coverageSqFtPerLb : 30m;
        var efficiency = transferEfficiency > 0 ? transferEfficiency / 100m : 0.65m;
        return Math.Round((surfaceAreaSqFt * quantity) / (coverage * efficiency), 2);
    }

    /// <summary>
    /// Resolves the display appearance (color name, code, finish) for a coat, preferring the linked
    /// <see cref="InventoryItem"/>'s values over whatever was typed into the quote form.
    /// The inventory record is the canonical source of truth — the form values are used as a fallback
    /// only when no inventory item is linked (e.g. custom/one-off powder).
    /// </summary>
    private static (string? ColorName, string? ColorCode, string? Finish) ResolveCoatAppearance(
        string? colorName,
        string? colorCode,
        string? finish,
        InventoryItem? inventoryItem)
    {
        if (inventoryItem == null)
            return (colorName, colorCode, finish);

        return (inventoryItem.Name, inventoryItem.ColorCode, inventoryItem.Finish);
    }

    /// <summary>
    /// Intermediate value object that normalises the three different source types
    /// (DTO, QuoteItem, JobItem) into a single shape before the shared BuildJobItem factory method.
    /// Using a seed class prevents subtle bugs where an overload forgets to map a new field.
    /// </summary>
    private sealed class JobItemSeed
    {
        public string Description { get; init; } = string.Empty;
        public decimal Quantity { get; init; }
        public string? ColorName { get; init; }
        public string? ColorCode { get; init; }
        public string? Finish { get; init; }
        public decimal? SurfaceArea { get; init; }
        public decimal SurfaceAreaSqFt { get; init; }
        public int? CatalogItemId { get; init; }
        public bool IsGenericItem { get; init; }
        public bool IsLaborItem { get; init; }
        public bool IsSalesItem { get; init; }
        public bool IsAiItem { get; init; }
        public string? Sku { get; init; }
        public decimal? ManualUnitPrice { get; init; }
        public decimal? PowderCostOverride { get; init; }
        public decimal UnitPrice { get; init; }
        public decimal TotalPrice { get; init; }
        public decimal LaborCost { get; init; }
        public bool RequiresSandblasting { get; init; }
        public bool RequiresMasking { get; init; }
        public int EstimatedMinutes { get; init; }
        public string? Notes { get; init; }
        public bool IncludePrepCost { get; init; }
        public string? Complexity { get; init; }
        public string? AiTags { get; init; }
        public int? AiPredictionId { get; init; }
    }

    /// <summary>Intermediate value object for coat creation — see <see cref="JobItemSeed"/> for rationale.</summary>
    private sealed class JobItemCoatSeed
    {
        public string CoatName { get; init; } = string.Empty;
        public int Sequence { get; init; }
        public int? InventoryItemId { get; init; }
        public string? ColorName { get; init; }
        public int? VendorId { get; init; }
        public string? ColorCode { get; init; }
        public string? Finish { get; init; }
        public decimal CoverageSqFtPerLb { get; init; }
        public decimal TransferEfficiency { get; init; }
        public decimal? PowderCostPerLb { get; init; }
        public decimal? PowderToOrder { get; init; }
        public string? Notes { get; init; }
        public bool NoExtraLayerCharge { get; init; }
    }

    /// <summary>Intermediate value object for prep service creation — see <see cref="JobItemSeed"/> for rationale.</summary>
    private sealed class JobItemPrepServiceSeed
    {
        public int PrepServiceId { get; init; }
        public int EstimatedMinutes { get; init; }
        public int? BlastSetupId { get; init; }
    }
}