using System.Text.Json;
using System.Text.Json.Serialization;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging.Abstractions;
using SVSim.Database;
using SVSim.Database.Enums;
using SVSim.Database.Models;

namespace SVSim.CardImport;

public static class Program
{
    private const string DefaultConnectionString =
        "Host=localhost;Database=svsim;Username=postgres;password=postgres";

    public static async Task<int> Main(string[] args)
    {
        if (args.Length < 1 || args[0] is "--help" or "-h")
        {
            Console.Error.WriteLine(
                "Usage: svsim-card-import <cards.json> [connection-string]\n" +
                "\n" +
                "  cards.json         Path to the loader's card dump (LitJson array of CardCSVData)\n" +
                "  connection-string  Postgres connection (falls back to NPGSQL_CONNECTION env var,\n" +
                $"                     then \"{DefaultConnectionString}\")");
            return 1;
        }

        string path = args[0];
        string connection = args.Length > 1
            ? args[1]
            : Environment.GetEnvironmentVariable("NPGSQL_CONNECTION") ?? DefaultConnectionString;

        if (!File.Exists(path))
        {
            Console.Error.WriteLine($"File not found: {path}");
            return 2;
        }

        Console.WriteLine($"Reading {path} ({new FileInfo(path).Length / 1024} KiB)...");
        var jsonOptions = new JsonSerializerOptions
        {
            PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower,
            NumberHandling = JsonNumberHandling.AllowReadingFromString,
        };

        List<CardInput>? input;
        await using (var fs = File.OpenRead(path))
        {
            input = await JsonSerializer.DeserializeAsync<List<CardInput>>(fs, jsonOptions);
        }
        if (input is null || input.Count == 0)
        {
            Console.Error.WriteLine("No card records parsed from input.");
            return 3;
        }
        Console.WriteLine($"Parsed {input.Count} card records.");

        var dbOptions = new DbContextOptionsBuilder<SVSimDbContext>()
            .UseNpgsql(connection)
            .Options;

        await using var context = new SVSimDbContext(NullLogger<SVSimDbContext>.Instance, dbOptions);

        // Apply any pending migrations first — bootstraps a fresh DB so CardImport can be the
        // very first thing run after `dotnet ef migrations add` (no need to run the server too).
        // Migration files have InsertData rows for the seeded master data already; runtime seeder
        // skip is fine.
        await context.Database.MigrateAsync();

        var classesById = await context.Classes.ToDictionaryAsync(c => c.Id);
        var existingSets = (await context.CardSets.ToListAsync()).ToDictionary(s => s.Id);
        var existingCards = (await context.Cards.ToListAsync()).ToDictionary(c => c.Id);
        Console.WriteLine(
            $"DB state before: {existingCards.Count} cards, {existingSets.Count} card sets, " +
            $"{classesById.Count} classes seeded.");

        int created = 0, updated = 0, skipped = 0, setsCreated = 0;

        foreach (var c in input)
        {
            if (!long.TryParse(c.CardId, out long id) || id == 0)
            {
                skipped++;
                continue;
            }

            int setId = ParseInt(c.CardSetId, 0);
            int clan = ParseInt(c.Clan, 0);
            int rarity = ParseInt(c.Rarity, 0);

            if (!existingSets.TryGetValue(setId, out var set))
            {
                set = new ShadowverseCardSetEntry
                {
                    Id = setId,
                    Name = $"Card Set {setId}",
                    IsInRotation = true,
                    IsBasic = false
                };
                context.CardSets.Add(set);
                existingSets[setId] = set;
                setsCreated++;
            }

            ClassEntry? classEntry = clan > 0 && classesById.TryGetValue(clan, out var ce) ? ce : null;
            var collection = new CardCollectionInfo
            {
                CraftCost = ParseInt(c.UseRedEther, 0),
                DustReward = ParseInt(c.GetRedEther, 0)
            };

            if (existingCards.TryGetValue(id, out var card))
            {
                card.Rarity = (Rarity)rarity;
                card.PrimaryResourceCost = ParseNullableInt(c.Cost);
                card.Attack = ParseNullableInt(c.Atk);
                card.Defense = ParseNullableInt(c.Life);
                card.Class = classEntry;
                card.CollectionInfo = collection;
                updated++;
            }
            else
            {
                card = new ShadowverseCardEntry
                {
                    Id = id,
                    Name = $"Card {id}",
                    Rarity = (Rarity)rarity,
                    PrimaryResourceCost = ParseNullableInt(c.Cost),
                    Attack = ParseNullableInt(c.Atk),
                    Defense = ParseNullableInt(c.Life),
                    Class = classEntry,
                    CollectionInfo = collection
                };
                set.Cards.Add(card);
                existingCards[id] = card;
                created++;
            }
        }

        Console.WriteLine(
            $"Saving: +{created} cards, ~{updated} updated, +{setsCreated} card sets, " +
            $"skipped {skipped} (bad/missing card_id)...");

        await context.SaveChangesAsync();

        Console.WriteLine("Done.");
        return 0;
    }

    private static int ParseInt(string? raw, int fallback) =>
        int.TryParse(raw, out int v) ? v : fallback;

    private static int? ParseNullableInt(string? raw) =>
        int.TryParse(raw, out int v) ? v : null;
}

/// <summary>
/// Lightweight projection over the CardCSVData fields we care about. The dump has many more
/// fields (PascalCase metadata + effect/voice/visual paths) — we ignore them; only the
/// snake_case CSV columns map here via the SnakeCaseLower naming policy.
/// </summary>
public class CardInput
{
    public string? CardId { get; set; }
    public string? CardSetId { get; set; }
    public string? Clan { get; set; }
    public string? Cost { get; set; }
    public string? Atk { get; set; }
    public string? Life { get; set; }
    public string? Rarity { get; set; }
    public string? GetRedEther { get; set; }
    public string? UseRedEther { get; set; }
}