<?php

namespace app\service;

use app\model\SysPermission;
use think\facade\Db;

/**
 * 后台权限目录：目录(dir) / 菜单(menu) / 按钮(btn)
 * 优先从 sys_permissions 表读取，表不存在时回退内置定义。
 */
class PermissionCatalog
{
    public static function builtinTree(): array
    {
        return [
            [
                'code'  => 'dir:overview',
                'name'  => '概览',
                'type'  => 'dir',
                'children' => [
                    [
                        'code' => 'menu:dashboard',
                        'name' => '数据概览',
                        'type' => 'menu',
                        'path' => '/dashboard',
                        'icon' => '📊',
                        'children' => [],
                    ],
                ],
            ],
            [
                'code'  => 'dir:org',
                'name'  => '组织架构',
                'type'  => 'dir',
                'children' => [
                    [
                        'code' => 'menu:users',
                        'name' => '用户管理',
                        'type' => 'menu',
                        'path' => '/users',
                        'icon' => '👥',
                        'children' => [
                            ['code' => 'btn:user:create', 'name' => '新增用户', 'type' => 'btn'],
                            ['code' => 'btn:user:edit', 'name' => '编辑用户', 'type' => 'btn'],
                            ['code' => 'btn:user:reset_password', 'name' => '重置密码', 'type' => 'btn'],
                            ['code' => 'btn:user:delete', 'name' => '删除用户', 'type' => 'btn'],
                        ],
                    ],
                    [
                        'code' => 'menu:departments',
                        'name' => '部门管理',
                        'type' => 'menu',
                        'path' => '/departments',
                        'icon' => '🏢',
                        'children' => [
                            ['code' => 'btn:dept:create', 'name' => '新增部门', 'type' => 'btn'],
                            ['code' => 'btn:dept:edit', 'name' => '编辑部门', 'type' => 'btn'],
                            ['code' => 'btn:dept:delete', 'name' => '删除部门', 'type' => 'btn'],
                        ],
                    ],
                    [
                        'code' => 'menu:roles',
                        'name' => '角色管理',
                        'type' => 'menu',
                        'path' => '/roles',
                        'icon' => '🛡️',
                        'children' => [
                            ['code' => 'btn:role:create', 'name' => '新增角色', 'type' => 'btn'],
                            ['code' => 'btn:role:edit', 'name' => '编辑角色', 'type' => 'btn'],
                            ['code' => 'btn:role:delete', 'name' => '删除角色', 'type' => 'btn'],
                        ],
                    ],
                ],
            ],
            [
                'code'  => 'dir:business',
                'name'  => '业务数据',
                'type'  => 'dir',
                'children' => [
                    [
                        'code' => 'menu:conversations',
                        'name' => '会话管理',
                        'type' => 'menu',
                        'path' => '/conversations',
                        'icon' => '💬',
                        'children' => [
                            ['code' => 'btn:conv:view_all', 'name' => '查看全部会话', 'type' => 'btn'],
                            ['code' => 'btn:conv:view_subordinate', 'name' => '查看下级部门会话', 'type' => 'btn'],
                        ],
                    ],
                    [
                        'code' => 'menu:memberships',
                        'name' => '会员等级',
                        'type' => 'menu',
                        'path' => '/memberships',
                        'icon' => '⭐',
                        'children' => [
                            ['code' => 'btn:membership:create', 'name' => '新增会员等级', 'type' => 'btn'],
                            ['code' => 'btn:membership:edit', 'name' => '编辑会员等级', 'type' => 'btn'],
                            ['code' => 'btn:membership:delete', 'name' => '删除会员等级', 'type' => 'btn'],
                        ],
                    ],
                ],
            ],
            [
                'code'  => 'dir:system',
                'name'  => '系统管理',
                'type'  => 'dir',
                'children' => [
                    [
                        'code' => 'menu:models',
                        'name' => 'AI 模型',
                        'type' => 'menu',
                        'path' => '/models',
                        'icon' => '🤖',
                        'children' => [
                            ['code' => 'btn:model:create', 'name' => '新增模型', 'type' => 'btn'],
                            ['code' => 'btn:model:edit', 'name' => '编辑模型', 'type' => 'btn'],
                            ['code' => 'btn:model:delete', 'name' => '删除模型', 'type' => 'btn'],
                            ['code' => 'btn:model:test', 'name' => '测试连接', 'type' => 'btn'],
                        ],
                    ],
                    [
                        'code' => 'menu:permissions',
                        'name' => '权限管理',
                        'type' => 'menu',
                        'path' => '/permissions',
                        'icon' => '🔑',
                        'children' => [
                            ['code' => 'btn:perm:create', 'name' => '新增权限', 'type' => 'btn'],
                            ['code' => 'btn:perm:edit', 'name' => '编辑权限', 'type' => 'btn'],
                            ['code' => 'btn:perm:delete', 'name' => '删除权限', 'type' => 'btn'],
                        ],
                    ],
                    [
                        'code' => 'menu:settings',
                        'name' => '系统设置',
                        'type' => 'menu',
                        'path' => '/settings',
                        'icon' => '🔧',
                        'children' => [
                            ['code' => 'btn:settings:save', 'name' => '保存设置', 'type' => 'btn'],
                        ],
                    ],
                ],
            ],
        ];
    }

    public static function tree(): array
    {
        try {
            if (!self::tableReady()) {
                return self::builtinTree();
            }

            $rows = SysPermission::order('sort_order')->order('id')->select()->toArray();
            if (!$rows) {
                return self::builtinTree();
            }

            return self::buildTreeFromRows($rows);
        } catch (\Throwable $e) {
            return self::builtinTree();
        }
    }

    public static function flatList(): array
    {
        try {
            if (!self::tableReady()) {
                return self::flattenBuiltin();
            }
            return SysPermission::order('sort_order')->order('id')->select()->toArray();
        } catch (\Throwable $e) {
            return self::flattenBuiltin();
        }
    }

    private static function tableReady(): bool
    {
        static $ready = null;
        if ($ready !== null) {
            return $ready;
        }
        try {
            $db = Db::getConfig('database') ?: env('DB_NAME', 'ai_chat');
            $rows = Db::query(
                'SELECT TABLE_NAME FROM information_schema.TABLES WHERE TABLE_SCHEMA = ? AND TABLE_NAME = ? LIMIT 1',
                [$db, 'sys_permissions']
            );
            $ready = !empty($rows);
        } catch (\Throwable $e) {
            $ready = false;
        }
        return $ready;
    }

    private static function buildTreeFromRows(array $rows): array
    {
        $byParent = [];
        foreach ($rows as $row) {
            $pid = $row['parent_id'] ? (int) $row['parent_id'] : 0;
            $byParent[$pid][] = $row;
        }

        $mapNode = function (array $row) use (&$mapNode, $byParent) {
            $children = [];
            foreach ($byParent[(int) $row['id']] ?? [] as $child) {
                $children[] = $mapNode($child);
            }
            return [
                'id'         => (int) $row['id'],
                'code'       => $row['code'],
                'name'       => $row['name'],
                'type'       => $row['type'],
                'path'       => $row['path'] ?? '',
                'icon'       => $row['icon'] ?? '',
                'parent_id'  => $row['parent_id'] ? (int) $row['parent_id'] : null,
                'sort_order' => (int) ($row['sort_order'] ?? 0),
                'is_system'  => (int) ($row['is_system'] ?? 0),
                'children'   => $children,
            ];
        };

        $tree = [];
        foreach ($byParent[0] ?? [] as $root) {
            $tree[] = $mapNode($root);
        }
        return $tree;
    }

    private static function flattenBuiltin(): array
    {
        $list = [];
        $walk = function (array $nodes, $parentId = null) use (&$walk, &$list) {
            foreach ($nodes as $i => $node) {
                $id = count($list) + 1;
                $list[] = [
                    'id'         => $id,
                    'type'       => $node['type'],
                    'code'       => $node['code'],
                    'name'       => $node['name'],
                    'parent_id'  => $parentId,
                    'path'       => $node['path'] ?? null,
                    'icon'       => $node['icon'] ?? null,
                    'sort_order' => $i,
                    'is_system'  => 1,
                ];
                if (!empty($node['children'])) {
                    $walk($node['children'], $id);
                }
            }
        };
        $walk(self::builtinTree());
        return $list;
    }

    public static function emptyPermissions(): array
    {
        $perms = [
            'can_access_admin' => false,
            'dirs'             => [],
            'menus'            => [],
            'buttons'          => [],
        ];
        foreach (self::legacyKeys() as $key) {
            $perms[$key] = false;
        }
        return $perms;
    }

    public static function fullPermissions(): array
    {
        $dirs = [];
        $menus = [];
        $buttons = [];

        foreach (self::tree() as $dir) {
            $dirs[] = $dir['code'];
            foreach ($dir['children'] ?? [] as $menu) {
                $menus[] = $menu['code'];
                foreach ($menu['children'] ?? [] as $btn) {
                    $buttons[] = $btn['code'];
                }
            }
        }

        $perms = [
            'can_access_admin' => true,
            'dirs'             => $dirs,
            'menus'            => $menus,
            'buttons'          => $buttons,
        ];
        foreach (self::legacyKeys() as $key) {
            $perms[$key] = true;
        }
        return $perms;
    }

    public static function legacyKeys(): array
    {
        return [
            'can_manage_users',
            'can_manage_roles',
            'can_manage_departments',
            'can_view_all_conversations',
            'can_view_subordinate_conversations',
            'can_manage_models',
            'can_manage_settings',
            'can_manage_memberships',
            'can_manage_permissions',
        ];
    }

    public static function normalize(array $input): array
    {
        $base = self::emptyPermissions();
        $dirs = array_values(array_unique(array_filter((array) ($input['dirs'] ?? []))));
        $menus = array_values(array_unique(array_filter((array) ($input['menus'] ?? []))));
        $buttons = array_values(array_unique(array_filter((array) ($input['buttons'] ?? []))));

        if (empty($menus) && empty($buttons) && empty($dirs)) {
            [$dirs, $menus, $buttons] = self::fromLegacy($input);
        }

        $perms = array_merge($base, [
            'can_access_admin' => !empty($input['can_access_admin']),
            'dirs'             => $dirs,
            'menus'            => $menus,
            'buttons'          => $buttons,
        ]);

        return self::syncLegacyFlags($perms);
    }

    public static function syncLegacyFlags(array $perms): array
    {
        $menus = $perms['menus'] ?? [];
        $buttons = $perms['buttons'] ?? [];

        $perms['can_manage_users'] = in_array('menu:users', $menus, true);
        $perms['can_manage_roles'] = in_array('menu:roles', $menus, true);
        $perms['can_manage_departments'] = in_array('menu:departments', $menus, true);
        $perms['can_manage_models'] = in_array('menu:models', $menus, true);
        $perms['can_manage_settings'] = in_array('menu:settings', $menus, true);
        $perms['can_manage_memberships'] = in_array('menu:memberships', $menus, true);
        $perms['can_manage_permissions'] = in_array('menu:permissions', $menus, true);
        $perms['can_view_all_conversations'] = in_array('btn:conv:view_all', $buttons, true);
        $perms['can_view_subordinate_conversations'] = in_array('btn:conv:view_subordinate', $buttons, true);

        if (in_array('menu:conversations', $menus, true)
            && empty($perms['can_view_all_conversations'])
            && empty($perms['can_view_subordinate_conversations'])) {
            $perms['can_view_subordinate_conversations'] = true;
            if (!in_array('btn:conv:view_subordinate', $buttons, true)) {
                $perms['buttons'][] = 'btn:conv:view_subordinate';
            }
        }

        return $perms;
    }

    private static function fromLegacy(array $input): array
    {
        $dirs = [];
        $menus = [];
        $buttons = [];

        $map = [
            'can_manage_users' => ['dir:org', 'menu:users', ['btn:user:create', 'btn:user:edit', 'btn:user:reset_password', 'btn:user:delete']],
            'can_manage_departments' => ['dir:org', 'menu:departments', ['btn:dept:create', 'btn:dept:edit', 'btn:dept:delete']],
            'can_manage_roles' => ['dir:org', 'menu:roles', ['btn:role:create', 'btn:role:edit', 'btn:role:delete']],
            'can_manage_memberships' => ['dir:business', 'menu:memberships', ['btn:membership:create', 'btn:membership:edit', 'btn:membership:delete']],
            'can_manage_models' => ['dir:system', 'menu:models', ['btn:model:create', 'btn:model:edit', 'btn:model:delete', 'btn:model:test']],
            'can_manage_settings' => ['dir:system', 'menu:settings', ['btn:settings:save']],
            'can_manage_permissions' => ['dir:system', 'menu:permissions', ['btn:perm:create', 'btn:perm:edit', 'btn:perm:delete']],
        ];

        foreach ($map as $key => [$dir, $menu, $btns]) {
            if (!empty($input[$key])) {
                $dirs[] = $dir;
                $menus[] = $menu;
                $buttons = array_merge($buttons, $btns);
            }
        }

        if (!empty($input['can_view_all_conversations']) || !empty($input['can_view_subordinate_conversations'])) {
            $dirs[] = 'dir:business';
            $menus[] = 'menu:conversations';
            if (!empty($input['can_view_all_conversations'])) {
                $buttons[] = 'btn:conv:view_all';
            }
            if (!empty($input['can_view_subordinate_conversations'])) {
                $buttons[] = 'btn:conv:view_subordinate';
            }
        }

        if (!empty($input['can_access_admin'])) {
            $dirs[] = 'dir:overview';
            $menus[] = 'menu:dashboard';
        }

        return [
            array_values(array_unique($dirs)),
            array_values(array_unique($menus)),
            array_values(array_unique($buttons)),
        ];
    }

    public static function hasCode(array $perms, string $code): bool
    {
        if ($code === 'can_access_admin') {
            return !empty($perms['can_access_admin']);
        }
        if (str_starts_with($code, 'dir:')) {
            return in_array($code, $perms['dirs'] ?? [], true);
        }
        if (str_starts_with($code, 'menu:')) {
            return in_array($code, $perms['menus'] ?? [], true);
        }
        if (str_starts_with($code, 'btn:')) {
            return in_array($code, $perms['buttons'] ?? [], true);
        }
        return !empty($perms[$code]);
    }

    public static function menuMeta(): array
    {
        $items = [];
        foreach (self::tree() as $dir) {
            foreach ($dir['children'] ?? [] as $menu) {
                $items[] = [
                    'id'      => $menu['id'] ?? null,
                    'code'    => $menu['code'],
                    'name'    => $menu['name'],
                    'path'    => $menu['path'] ?? '',
                    'icon'    => $menu['icon'] ?? '',
                    'dir'     => $dir['code'],
                    'dirName' => $dir['name'],
                ];
            }
        }
        return $items;
    }
}