using System.Security.Claims;
using MiaoJiZhang.Api.Contracts;
using MiaoJiZhang.Domain.Entities;
using MiaoJiZhang.Domain.Enums;
using MiaoJiZhang.Infrastructure.Persistence;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace MiaoJiZhang.Api.Controllers;

[ApiController]
[Authorize]
[Route("api/ledgers")]
public class LedgersController(AppDbContext db) : ControllerBase
{
    private long Uid => long.Parse(User.FindFirstValue(ClaimTypes.NameIdentifier) ?? User.FindFirstValue("sub")!);

    [HttpGet]
    public async Task<IActionResult> List() =>
        Ok(await db.Ledgers.Where(l => l.OwnerId == Uid)
            .OrderByDescending(l => l.IsDefault).ThenBy(l => l.CreatedAt)
            .Select(l => new { l.Id, l.Name, l.IconKey, l.IsDefault, TxCount = db.Transactions.IgnoreQueryFilters().Count(t => t.LedgerId == l.Id && t.UserId == Uid) })
            .ToListAsync());

    [HttpPost]
    public async Task<IActionResult> Create([FromBody] CreateLedgerReq req)
    {
        if (string.IsNullOrWhiteSpace(req.Name) || req.Name.Length > 12)
            return BadRequest(new ApiError("NAME_INVALID", "账本名 1-12 个字"));
        var maxCount = int.TryParse((await db.AppConfigs.FirstOrDefaultAsync(c => c.Key == "system.max_ledgers_per_user"))?.Value, out var v) ? v : 10;
        if (await db.Ledgers.CountAsync(l => l.OwnerId == Uid) >= maxCount)
            return BadRequest(new ApiError("LIMIT_REACHED", $"每人最多 {maxCount} 个账本"));
        var ledger = new Ledger { OwnerId = Uid, Name = req.Name.Trim(), IconKey = req.IconKey ?? "wallet" };
        db.Ledgers.Add(ledger);
        await db.SaveChangesAsync();
        return Ok(new { ledger.Id, ledger.Name, ledger.IconKey, ledger.IsDefault, TxCount = 0 });
    }

    [HttpPut("{id:long}/default")]
    public async Task<IActionResult> SetDefault(long id)
    {
        var target = await db.Ledgers.FirstOrDefaultAsync(l => l.Id == id && l.OwnerId == Uid);
        if (target is null) return NotFound(new ApiError("LEDGER_NOT_FOUND", "账本不存在"));
        await db.Ledgers.Where(l => l.OwnerId == Uid && l.IsDefault).ExecuteUpdateAsync(s => s.SetProperty(l => l.IsDefault, false));
        target.IsDefault = true;
        await db.SaveChangesAsync();
        return NoContent();
    }

    [HttpPut("{id:long}")]
    public async Task<IActionResult> Rename(long id, UpdateLedgerReq req)
    {
        if (string.IsNullOrWhiteSpace(req.Name) || req.Name.Trim().Length > 12)
            return BadRequest(new ApiError("NAME_INVALID", "账本名 1-12 个字"));
        var ledger = await db.Ledgers.FirstOrDefaultAsync(l => l.Id == id && l.OwnerId == Uid);
        if (ledger is null) return NotFound(new ApiError("LEDGER_NOT_FOUND", "账本不存在"));
        ledger.Name = req.Name.Trim();
        if (!string.IsNullOrWhiteSpace(req.IconKey)) ledger.IconKey = req.IconKey.Trim();
        await db.SaveChangesAsync();
        return Ok(new LedgerDto(ledger.Id, ledger.Name, ledger.IconKey, ledger.IsDefault));
    }

    [HttpPut("reorder")]
    public async Task<IActionResult> Reorder(ReorderCategoriesRequest req)
    {
        if (req.Type is not ("income" or "expense"))
            return BadRequest(new ApiError("TYPE_INVALID", "收支类型必须是 expense 或 income"));
        if (req.CategoryIds.Count != req.CategoryIds.Distinct().Count())
            return BadRequest(new ApiError("ORDER_INVALID", "分类排序中存在重复项"));

        var type = req.Type == "income"
            ? TransactionType.Income
            : TransactionType.Expense;
        var categories = await db.Categories
            .Where(c => c.UserId == Uid && c.Type == type && !c.IsDeleted)
            .ToListAsync();
        if (categories.Count != req.CategoryIds.Count ||
            categories.Select(c => c.Id).ToHashSet()
                .SetEquals(req.CategoryIds) is false)
            return BadRequest(new ApiError("ORDER_INVALID", "请提交完整的自定义分类顺序"));

        var byId = categories.ToDictionary(c => c.Id);
        for (var index = 0; index < req.CategoryIds.Count; index++)
            byId[req.CategoryIds[index]].SortOrder = 1000 + index;
        await db.SaveChangesAsync();
        return NoContent();
    }

    [HttpDelete("{id:long}")]
    public async Task<IActionResult> Delete(long id)
    {
        var ledger = await db.Ledgers.FirstOrDefaultAsync(l => l.Id == id && l.OwnerId == Uid);
        if (ledger is null) return NotFound(new ApiError("LEDGER_NOT_FOUND", "账本不存在"));
        if (ledger.IsDefault)
            return Conflict(new ApiError("DEFAULT_LEDGER", "默认账本不能删除，请先切换到其他账本"));
        var hasTransactions = await db.Transactions.IgnoreQueryFilters()
            .AnyAsync(t => t.UserId == Uid && t.LedgerId == id);
        var hasBudgets = await db.Budgets.AnyAsync(b => b.UserId == Uid && b.LedgerId == id);
        if (hasTransactions || hasBudgets)
            return Conflict(new ApiError("LEDGER_NOT_EMPTY", "仅可删除没有账单和预算的账本"));
        db.Ledgers.Remove(ledger);
        await db.SaveChangesAsync();
        return NoContent();
    }
}

public record CreateLedgerReq(string Name, string? IconKey);
public record UpdateLedgerReq(string Name, string? IconKey);

[ApiController]
[Authorize]
[Route("api/categories")]
public class CategoriesController(AppDbContext db) : ControllerBase
{
    internal static readonly HashSet<string> AllowedIcons =
    [
        "food", "cup", "cart", "house", "rent", "metro", "car", "plane",
        "phone", "wifi", "shirt", "beauty", "pill", "sport", "book", "baby",
        "pet", "game", "gift", "wallet", "money", "briefcase", "chart",
        "interest", "refund", "card", "insurance", "tax", "receipt",
        "camera", "target", "sparkle", "tag",
    ];

    internal static readonly HashSet<string> AllowedColors =
    [
        "mint", "teal", "aqua", "cyan", "sky", "blue",
        "navy", "indigo", "violet", "plum", "orchid", "rose",
        "coral", "red", "orange", "amber", "peach", "sand",
        "lime", "olive", "forest", "slate", "cocoa", "graphite",
    ];

    private long Uid => long.Parse(User.FindFirstValue(ClaimTypes.NameIdentifier) ?? User.FindFirstValue("sub")!);

    internal static string NormalizeIcon(string? iconKey) => iconKey?.Trim() switch
    {
        "shopping" => "cart",
        "transport" => "metro",
        "home" => "house",
        "salary" => "money",
        { Length: > 0 } value => value,
        _ => "tag",
    };

    [HttpGet]
    public async Task<ActionResult<List<CategoryDto>>> List([FromQuery] string type = "expense")
    {
        if (type is not ("income" or "expense"))
            return BadRequest(new ApiError("TYPE_INVALID", "收支类型必须是 expense 或 income"));
        var t = type == "income" ? TransactionType.Income : TransactionType.Expense;
        var list = await db.Categories
            .Where(c => !c.IsDeleted && c.Type == t && (c.UserId == null || c.UserId == Uid))
            .OrderBy(c => c.SortOrder)
            .Select(c => new CategoryDto(
                c.Id, c.Name, c.IconKey, type,
                c.SortOrder, c.UserId != null, c.ColorKey))
            .ToListAsync();
        return Ok(list);
    }

    [HttpPost]
    public async Task<ActionResult<CategoryDto>> Create(CreateCategoryRequest req)
    {
        if (string.IsNullOrWhiteSpace(req.Name) || req.Name.Length > 8)
            return BadRequest(new ApiError("NAME_INVALID", "分类名 1-8 个字"));
        if (req.Type is not ("income" or "expense"))
            return BadRequest(new ApiError("TYPE_INVALID", "收支类型必须是 expense 或 income"));
        var t = req.Type == "income" ? TransactionType.Income : TransactionType.Expense;
        var iconKey = NormalizeIcon(req.IconKey);
        if (!AllowedIcons.Contains(iconKey))
            return BadRequest(new ApiError("ICON_INVALID", "分类图标不存在"));
        var colorKey = string.IsNullOrWhiteSpace(req.ColorKey)
            ? "mint"
            : req.ColorKey.Trim();
        if (!AllowedColors.Contains(colorKey))
            return BadRequest(new ApiError("COLOR_INVALID", "分类颜色不存在"));
        if (await db.Categories.AnyAsync(c => !c.IsDeleted && c.Type == t && c.Name == req.Name && (c.UserId == null || c.UserId == Uid)))
            return Conflict(new ApiError("NAME_TAKEN", "分类已存在"));
        var maxSort = await db.Categories
            .Where(c => c.Type == t && (c.UserId == null || c.UserId == Uid))
            .MaxAsync(c => (int?)c.SortOrder) ?? 0;
        var cat = new Category
        {
            UserId = Uid,
            Type = t,
            Name = req.Name.Trim(),
            IconKey = iconKey,
            ColorKey = colorKey,
            SortOrder = Math.Max(999, maxSort) + 1,
        };
        db.Categories.Add(cat);
        await db.SaveChangesAsync();
        return Ok(new CategoryDto(
            cat.Id, cat.Name, cat.IconKey, req.Type,
            cat.SortOrder, true, cat.ColorKey));
    }

    [HttpPut("{id:long}")]
    public async Task<ActionResult<CategoryDto>> Update(long id, UpdateCategoryRequest req)
    {
        if (string.IsNullOrWhiteSpace(req.Name) || req.Name.Trim().Length > 8)
            return BadRequest(new ApiError("NAME_INVALID", "分类名 1-8 个字"));
        var category = await db.Categories.FirstOrDefaultAsync(c =>
            c.Id == id && c.UserId == Uid && !c.IsDeleted);
        if (category is null)
            return NotFound(new ApiError("CATEGORY_NOT_FOUND", "分类不存在或非自定义分类"));
        var name = req.Name.Trim();
        if (await db.Categories.AnyAsync(c => c.Id != id && !c.IsDeleted &&
                c.Type == category.Type && c.Name == name &&
                (c.UserId == null || c.UserId == Uid)))
            return Conflict(new ApiError("NAME_TAKEN", "分类已存在"));
        var iconKey = NormalizeIcon(req.IconKey);
        if (!AllowedIcons.Contains(iconKey))
            return BadRequest(new ApiError("ICON_INVALID", "分类图标不存在"));
        var colorKey = req.ColorKey is null
            ? category.ColorKey
            : req.ColorKey.Trim();
        if (!AllowedColors.Contains(colorKey))
            return BadRequest(new ApiError("COLOR_INVALID", "分类颜色不存在"));
        category.Name = name;
        category.IconKey = iconKey;
        category.ColorKey = colorKey;
        category.SortOrder = Math.Max(1000, req.SortOrder);
        await db.SaveChangesAsync();
        return Ok(new CategoryDto(
            category.Id, category.Name, category.IconKey,
            category.Type == TransactionType.Income ? "income" : "expense",
            category.SortOrder, true, category.ColorKey));
    }

    [HttpPut("reorder")]
    public async Task<IActionResult> Reorder(ReorderCategoriesRequest req)
    {
        if (req.Type is not ("income" or "expense"))
            return BadRequest(new ApiError("TYPE_INVALID", "收支类型必须是 expense 或 income"));
        if (req.CategoryIds.Count != req.CategoryIds.Distinct().Count())
            return BadRequest(new ApiError("ORDER_INVALID", "分类排序中存在重复项"));

        var type = req.Type == "income"
            ? TransactionType.Income
            : TransactionType.Expense;
        var categories = await db.Categories
            .Where(c => c.UserId == Uid && c.Type == type && !c.IsDeleted)
            .ToListAsync();
        if (categories.Count != req.CategoryIds.Count ||
            categories.Select(c => c.Id).ToHashSet()
                .SetEquals(req.CategoryIds) is false)
            return BadRequest(new ApiError("ORDER_INVALID", "请提交完整的自定义分类顺序"));

        var byId = categories.ToDictionary(c => c.Id);
        for (var index = 0; index < req.CategoryIds.Count; index++)
            byId[req.CategoryIds[index]].SortOrder = 1000 + index;
        await db.SaveChangesAsync();
        return NoContent();
    }

    [HttpDelete("{id:long}")]
    public async Task<IActionResult> Delete(long id)
    {
        var cat = await db.Categories.FirstOrDefaultAsync(c => c.Id == id && c.UserId == Uid);
        if (cat is null) return NotFound(new ApiError("CATEGORY_NOT_FOUND", "分类不存在或非自定义分类"));
        cat.IsDeleted = true;
        await db.SaveChangesAsync();
        return NoContent();
    }
}

public record ReorderCategoriesRequest(string Type, List<long> CategoryIds);