<?php

namespace App\Services\Agent;

use App\Models\Agent\Agent;
use App\Models\Agent\AgentFlowCommissionProfile;
use Illuminate\Database\Eloquent\Builder;
use Illuminate\Support\Facades\DB;

class AgentFlowCommissionProfileService
{
    public function __construct(private AgentFlowCommissionAssignmentService $assignments)
    {
    }

    public function paginate(array $params, ?Agent $owner = null): array
    {
        $page = max(1, (int) ($params['page'] ?? 1));
        $limit = min(100, max(1, (int) ($params['limit'] ?? 20)));
        $query = $this->ownedQuery($owner);
        if (!empty($params['name'])) $query->where('name', 'like', '%' . $params['name'] . '%');
        $total = (clone $query)->count();
        $list = $query->orderByDesc('is_default')->orderByDesc('id')->forPage($page, $limit)->get();
        if ($owner) {
            $list->each(fn (AgentFlowCommissionProfile $profile) => $profile->setAttribute('editable', true));
        }
        return compact('total', 'page', 'limit', 'list');
    }

    public function paginateSelectable(Agent $agent, array $params): array
    {
        $agent->loadMissing('flowCommissionProfile');
        if (!$agent->flowCommissionProfile) throw new \RuntimeException('当前代理未关联流水佣金方案');
        $page = max(1, (int) ($params['page'] ?? 1));
        $limit = min(100, max(1, (int) ($params['limit'] ?? 20)));
        $query = AgentFlowCommissionProfile::query()->where(function (Builder $query) use ($agent) {
            $query->whereNull('owner_agent_id')->orWhere('owner_agent_id', $agent->id);
        });
        foreach (AgentFlowCommissionProfile::RATE_FIELDS as $field) {
            $query->where($field, '<=', (string) $agent->flowCommissionProfile->{$field});
        }
        if (!empty($params['name'])) $query->where('name', 'like', '%' . $params['name'] . '%');
        $total = (clone $query)->count();
        $list = $query->orderByRaw('owner_agent_id is null')->orderByDesc('is_default')->orderByDesc('id')
            ->forPage($page, $limit)->get();
        $list->each(function (AgentFlowCommissionProfile $profile) use ($agent) {
            $profile->setAttribute('editable', $profile->isOwnedBy((int) $agent->id));
        });
        return compact('total', 'page', 'limit', 'list');
    }

    public function save(array $data, ?int $adminId = null, ?Agent $owner = null): AgentFlowCommissionProfile
    {
        return DB::transaction(function () use ($data, $adminId, $owner) {
            $profiles = $this->ownedQuery($owner)->orderBy('id')->lockForUpdate()->get(['id', 'is_default']);
            $profile = empty($data['id'])
                ? new AgentFlowCommissionProfile()
                : AgentFlowCommissionProfile::query()->lockForUpdate()->findOrFail($data['id']);
            if ($profile->exists) $this->assertOwned($profile, $owner);
            else $profile->owner_agent_id = $owner?->id;

            $oldDefaultId = $profiles->firstWhere('is_default', 1)?->id;
            $isDefault = !empty($data['is_default']);
            if ($profile->exists && (int) $oldDefaultId === (int) $profile->id && !$isDefault) {
                throw new \RuntimeException('默认流水方案必须始终保留一条，请先将其他方案设为默认');
            }
            $name = trim((string) $data['name']);
            if ($name === '') throw new \InvalidArgumentException('流水方案名称不能为空');
            $duplicate = $this->ownedQuery($owner)->where('name', $name)
                ->when($profile->exists, fn ($query) => $query->where('id', '<>', $profile->id))->exists();
            if ($duplicate) throw new \InvalidArgumentException('流水方案名称已存在');

            $profile->name = $name;
            foreach (AgentFlowCommissionProfile::RATE_FIELDS as $field) $profile->{$field} = (string) $data[$field];
            if ($owner) $this->assertRatesWithinOwner($owner, $profile);
            $willBeDefault = $isDefault || (!$profile->exists && !$oldDefaultId);
            $profile->is_default = $willBeDefault ? 1 : 0;
            $snapshotChanged = !$profile->exists || $profile->isDirty(AgentFlowCommissionProfile::RATE_FIELDS);
            $affectedAgentIds = [];
            if ($snapshotChanged && $profile->exists) {
                $affectedAgentIds = Agent::query()->where('flow_commission_profile_id', $profile->id)
                    ->pluck('id')->map(fn ($id) => (int) $id)->all();
            }
            if ($willBeDefault) {
                $defaultAgentIds = $this->defaultMigrationQuery($oldDefaultId, $profile, $owner)
                    ->pluck('id')->map(fn ($id) => (int) $id)->all();
                $affectedAgentIds = array_values(array_unique(array_merge($affectedAgentIds, $defaultAgentIds)));
            }
            $this->assertHierarchy($affectedAgentIds, $profile);
            $profile->save();

            if ($willBeDefault) {
                $this->ownedQuery($owner)->where('id', '<>', $profile->id)->update(['is_default' => 0]);
                $this->defaultMigrationQuery($oldDefaultId, $profile, $owner)
                    ->update(['flow_commission_profile_id' => $profile->id]);
            }
            $this->assignments->assignMany($affectedAgentIds, $profile, now()->toDateString(), $adminId);
            return $profile->fresh();
        });
    }

    public function delete(int $id, ?int $adminId = null, ?Agent $owner = null): void
    {
        DB::transaction(function () use ($id, $adminId, $owner) {
            $profile = AgentFlowCommissionProfile::query()->lockForUpdate()->findOrFail($id);
            $this->assertOwned($profile, $owner);
            if ((int) $profile->is_default === 1) throw new \RuntimeException('默认流水方案不能删除');
            $default = $this->ownedQuery($owner)->where('is_default', 1)->lockForUpdate()->first();
            if (!$default) throw new \RuntimeException('缺少默认流水方案，不能删除');
            $agentIds = $this->agentsUsingProfile($profile->id, $owner);
            $this->assertHierarchy($agentIds, $default);
            $this->assignments->assignMany($agentIds, $default, now()->toDateString(), $adminId);
            Agent::query()->where('flow_commission_profile_id', $profile->id)
                ->when($owner, fn ($query) => $query->where('parent_id', $owner->id))
                ->update(['flow_commission_profile_id' => $default->id]);
            $profile->delete();
        });
    }

    private function ownedQuery(?Agent $owner): Builder
    {
        $query = AgentFlowCommissionProfile::query();
        return $owner
            ? $query->where('owner_agent_id', $owner->id)
            : $query->whereNull('owner_agent_id');
    }

    private function defaultMigrationQuery(?int $oldDefaultId, AgentFlowCommissionProfile $profile, ?Agent $owner): Builder
    {
        $query = Agent::query()->where(function (Builder $query) use ($oldDefaultId, $profile) {
            $query->whereNull('flow_commission_profile_id');
            if ($oldDefaultId && (int) $oldDefaultId !== (int) $profile->id) {
                $query->orWhere('flow_commission_profile_id', $oldDefaultId);
            }
        });
        return $owner ? $query->where('parent_id', $owner->id) : $query;
    }

    private function agentsUsingProfile(int $profileId, ?Agent $owner): array
    {
        $ids = Agent::query()->where('flow_commission_profile_id', $profileId)
            ->pluck('id')->map(fn ($agentId) => (int) $agentId);
        if ($owner) {
            $childIds = Agent::query()->where('parent_id', $owner->id)
                ->pluck('id')->map(fn ($agentId) => (int) $agentId);
            if ($ids->diff($childIds)->isNotEmpty()) {
                throw new \RuntimeException('该流水方案仍被非直属下级使用，不能删除');
            }
            return $ids->intersect($childIds)->values()->all();
        }
        return $ids->all();
    }

    private function assertOwned(AgentFlowCommissionProfile $profile, ?Agent $owner): void
    {
        if ($owner) {
            if (!$profile->isOwnedBy((int) $owner->id)) {
                throw new \RuntimeException('无权操作该流水方案');
            }
            return;
        }
        if (!$profile->isOfficial()) {
            throw new \RuntimeException('总后台只能维护官方流水方案');
        }
    }

    private function assertRatesWithinOwner(Agent $owner, AgentFlowCommissionProfile $profile): void
    {
        $owner->loadMissing('flowCommissionProfile');
        if (!$owner->flowCommissionProfile) throw new \RuntimeException('当前代理未关联流水佣金方案');
        foreach (AgentFlowCommissionProfile::RATE_FIELDS as $field) {
            if (bccomp((string) $profile->{$field}, (string) $owner->flowCommissionProfile->{$field}, 4) > 0) {
                throw new \RuntimeException('下级流水方案不能高于当前代理方案');
            }
        }
    }

    private function assertHierarchy(array $agentIds, AgentFlowCommissionProfile $candidate): void
    {
        $agentIds = array_values(array_unique(array_map('intval', $agentIds)));
        if ($agentIds === []) return;
        $affected = array_fill_keys($agentIds, true);
        $agents = Agent::query()->with([
            'parent.flowCommissionProfile',
            'children.flowCommissionProfile',
        ])->whereIn('id', $agentIds)->get();
        foreach ($agents as $agent) {
            if ($agent->parent) {
                foreach (AgentFlowCommissionProfile::RATE_FIELDS as $field) {
                    if (!isset($affected[(int) $agent->parent->id]) && !$agent->parent->flowCommissionProfile) {
                        throw new \RuntimeException('上级代理未关联流水佣金方案');
                    }
                    $parentRate = isset($affected[(int) $agent->parent->id])
                        ? (string) $candidate->{$field}
                        : (string) $agent->parent->flowCommissionProfile->{$field};
                    if (bccomp((string) $candidate->{$field}, $parentRate, 4) > 0) {
                        throw new \RuntimeException('修改后的流水方案会高于上级代理方案');
                    }
                }
            }
            foreach ($agent->children as $child) {
                foreach (AgentFlowCommissionProfile::RATE_FIELDS as $field) {
                    if (!isset($affected[(int) $child->id]) && !$child->flowCommissionProfile) {
                        throw new \RuntimeException('下级代理未关联流水佣金方案');
                    }
                    $childRate = isset($affected[(int) $child->id])
                        ? (string) $candidate->{$field}
                        : (string) $child->flowCommissionProfile->{$field};
                    if (bccomp((string) $candidate->{$field}, $childRate, 4) < 0) {
                        throw new \RuntimeException('修改后的流水方案会低于下级代理方案');
                    }
                }
            }
        }
    }
}