using System.Security.Claims;
using AgriculturalPlatform.Api.Data;
using AgriculturalPlatform.Api.Dtos;
using AgriculturalPlatform.Api.Models;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace AgriculturalPlatform.Api.Controllers;

/// <summary>菜单/权限管理</summary>
[ApiController]
[Route("api/menus")]
[Authorize]
public class MenusController(AppDbContext db) : ControllerBase
{
    /// <summary>菜单树（全部）</summary>
    [HttpGet]
    public async Task<ActionResult> Tree()
    {
        var menus = await db.SysMenus.AsNoTracking().OrderBy(m => m.Sort).ThenBy(m => m.Id).ToListAsync();
        return Ok(BuildTree(menus, null));
    }

    /// <summary>当前登录用户的菜单与权限</summary>
    [HttpGet("my")]
    public async Task<ActionResult> My()
    {
        var userId = User.FindFirstValue(ClaimTypes.NameIdentifier);
        if (userId is null) return Unauthorized();

        // 用户角色 -> 菜单
        var user = await db.Users.Include(u => u.SysRole).FirstOrDefaultAsync(u => u.Id == int.Parse(userId));
        if (user is null) return Unauthorized();

        int[] menuIds;
        if (user.SysRole?.Code == "super_admin" || user.Role == UserRole.SuperAdmin)
        {
            menuIds = await db.SysMenus.Select(m => m.Id).ToArrayAsync();
        }
        else if (user.RoleId is int rid)
        {
            menuIds = await db.SysRoleMenus.Where(rm => rm.RoleId == rid).Select(rm => rm.MenuId).ToArrayAsync();
        }
        else
        {
            menuIds = Array.Empty<int>();
        }

        var menus = await db.SysMenus.AsNoTracking()
            .Where(m => menuIds.Contains(m.Id))
            .OrderBy(m => m.Sort).ThenBy(m => m.Id)
            .ToListAsync();
        var tree = BuildTree(menus, null);
        var permissions = menus.Where(m => !string.IsNullOrWhiteSpace(m.Permission)).Select(m => m.Permission).Distinct().ToArray();
        return Ok(new { menus = tree, permissions });
    }

    private static List<MenuDto> BuildTree(List<SysMenu> all, int? parentId)
    {
        return all.Where(m => m.ParentId == parentId)
            .Select(m => new MenuDto(
                m.Id, m.ParentId, m.Name, m.Path, m.Component, m.Icon, m.Type,
                m.Permission, m.Visible, m.Sort, BuildTree(all, m.Id)))
            .ToList();
    }

    /// <summary>新增菜单</summary>
    [HttpPost]
    public async Task<ActionResult> Create(MenuSaveRequest req)
    {
        var menu = new SysMenu
        {
            ParentId = req.ParentId, Name = req.Name, Path = req.Path, Component = req.Component,
            Icon = req.Icon, Type = req.Type, Permission = req.Permission, Visible = req.Visible,
            Sort = req.Sort, CreatedAt = DateTime.Now
        };
        db.SysMenus.Add(menu);
        await db.SaveChangesAsync();
        return Ok(new { message = "保存成功", id = menu.Id });
    }

    /// <summary>修改菜单</summary>
    [HttpPut("{id:int}")]
    public async Task<ActionResult> Update(int id, MenuSaveRequest req)
    {
        var menu = await db.SysMenus.FindAsync(id);
        if (menu is null) return NotFound();
        if (req.ParentId == id) return BadRequest(new { message = "父级不能选择自身" });

        menu.ParentId = req.ParentId; menu.Name = req.Name; menu.Path = req.Path;
        menu.Component = req.Component; menu.Icon = req.Icon; menu.Type = req.Type;
        menu.Permission = req.Permission; menu.Visible = req.Visible; menu.Sort = req.Sort;
        await db.SaveChangesAsync();
        return Ok(new { message = "保存成功" });
    }

    /// <summary>删除菜单（有子菜单或已被角色引用时禁止删除）</summary>
    [HttpDelete("{id:int}")]
    public async Task<IActionResult> Delete(int id)
    {
        if (await db.SysMenus.AnyAsync(m => m.ParentId == id))
            return BadRequest(new { message = "请先删除子菜单" });
        if (await db.SysRoleMenus.AnyAsync(rm => rm.MenuId == id))
            return BadRequest(new { message = "该菜单已被角色引用，请先解除关联" });
        var menu = await db.SysMenus.FindAsync(id);
        if (menu is null) return NotFound();
        db.SysMenus.Remove(menu);
        await db.SaveChangesAsync();
        return Ok(new { message = "删除成功" });
    }
}