import { Inject, Injectable } from '@nestjs/common';
import type { CreateWatermarkDerivativeRequest, WatermarkDerivative } from '@atlas/contracts';
import type { Database } from '@atlas/database';
import { ApiError } from '../common/api-error.js';
import { IdempotencyService } from '../common/idempotency.service.js';
import { DATABASE } from '../database/database.module.js';
import { MediaService } from './media.service.js';

type DerivativeRow = {
    id: string;
    status: WatermarkDerivative['status'];
    source_asset_id: string;
    watermark_template_id: string;
    watermark_template_version: number;
    output_asset_id: string | null;
    error_code: string | null;
    content_type: string | null;
    byte_size: string | null;
    width_px: number | null;
    height_px: number | null;
    asset_created_at: Date | string | null;
};

@Injectable()
export class WatermarkDerivativeService {
    public constructor(
        @Inject(DATABASE) private readonly database: Database,
        @Inject(IdempotencyService) private readonly idempotency: IdempotencyService,
        @Inject(MediaService) private readonly media: MediaService,
    ) {}

    /** 创建任务时固定模板版本，并与进度和 Outbox 一起提交。 */
    public async create(
        workspaceId: string,
        userId: string,
        assetId: string,
        key: string,
        input: CreateWatermarkDerivativeRequest,
    ) {
        return this.idempotency.run({
            workspaceId,
            userId,
            method: 'POST',
            path: `/api/media-assets/${assetId}/watermark-derivatives`,
            key,
            request: input,
        }, async (tx) => {
            const source = await tx.query<{ id: string }>(
                `SELECT id FROM atlas.media_assets
                 WHERE id = $1 AND content_type IN ('image/jpeg', 'image/png', 'image/webp')
                   AND byte_size <= 20971520 AND width_px BETWEEN 1 AND 10000
                   AND height_px BETWEEN 1 AND 10000`,
                [assetId],
            );
            if (!source.rows[0]) throw new ApiError(404, 'RESOURCE_NOT_FOUND', '图片素材不存在或不可处理');
            if (input.product_id) {
                const product = await tx.query<{ id: string }>(
                    'SELECT id FROM atlas.products WHERE id = $1',
                    [input.product_id],
                );
                if (!product.rows[0]) throw new ApiError(404, 'RESOURCE_NOT_FOUND', '商品不存在');
            }
            const template = await tx.query<{ id: string; current_version: number }>(
                `SELECT id, current_version FROM atlas.watermark_templates
                 WHERE id = $1 AND status = 'active' AND deleted_at IS NULL`,
                [input.watermark_template_id],
            );
            if (!template.rows[0]) throw new ApiError(404, 'RESOURCE_NOT_FOUND', '水印模板不存在');
            const version = template.rows[0].current_version;
            const created = await tx.query<{ id: string }>(
                `INSERT INTO atlas.media_watermark_derivatives
                 (workspace_id, product_id, source_asset_id, watermark_template_id,
                  watermark_template_version, created_by_user_id)
                 VALUES (current_setting('app.workspace_id')::uuid, $1, $2, $3, $4, $5)
                 RETURNING id`,
                [input.product_id ?? null, assetId, input.watermark_template_id, version, userId],
            );
            const id = created.rows[0].id;
            await tx.query(
                `INSERT INTO atlas.operations
                 (id, workspace_id, kind, resource_type, resource_id, created_by_user_id)
                 VALUES ($1, current_setting('app.workspace_id')::uuid,
                         'media_watermark_derivative', 'media_derivative', $1, $2)`,
                [id, userId],
            );
            await tx.query(
                `INSERT INTO atlas.outbox_events
                 (workspace_id, aggregate_type, aggregate_id, event_type, event_payload, deduplication_key)
                 VALUES (current_setting('app.workspace_id')::uuid, 'media_derivative', $1,
                         'media.watermark_derivative.requested',
                         jsonb_build_object('derivative_id', $1::uuid), $1::text)`,
                [id],
            );
            return { status: 202, body: { data: {
                id,
                status: 'queued',
                source_asset_id: assetId,
                watermark_template_id: input.watermark_template_id,
                watermark_template_version: version,
                output_asset: null,
                error_code: null,
            } satisfies WatermarkDerivative } };
        });
    }

    /** 成功结果读取时才签发短时预览地址。 */
    public async read(workspaceId: string, derivativeId: string): Promise<WatermarkDerivative> {
        const row = await this.database.workspaceTransaction(workspaceId, async (tx) => {
            const result = await tx.query<DerivativeRow>(
                `SELECT d.id, d.status, d.source_asset_id, d.watermark_template_id,
                        d.watermark_template_version, d.output_asset_id, d.error_code,
                        a.content_type, a.byte_size::text, a.width_px, a.height_px,
                        a.created_at AS asset_created_at
                 FROM atlas.media_watermark_derivatives d
                 LEFT JOIN atlas.media_assets a ON a.id = d.output_asset_id
                 WHERE d.id = $1`,
                [derivativeId],
            );
            return result.rows[0] ?? null;
        });
        if (!row) throw new ApiError(404, 'RESOURCE_NOT_FOUND', '水印处理任务不存在');
        const access = row.output_asset_id
            ? await this.media.accessUrl(workspaceId, row.output_asset_id)
            : null;
        return {
            id: row.id,
            status: row.status,
            source_asset_id: row.source_asset_id,
            watermark_template_id: row.watermark_template_id,
            watermark_template_version: row.watermark_template_version,
            error_code: row.error_code,
            output_asset: row.output_asset_id && access ? {
                id: row.output_asset_id,
                content_type: row.content_type!,
                byte_size: Number(row.byte_size),
                width_px: row.width_px,
                height_px: row.height_px,
                created_at: row.asset_created_at instanceof Date
                    ? row.asset_created_at.toISOString() : String(row.asset_created_at),
                preview_url: access.url,
                preview_url_expires_at: access.expires_at,
            } : null,
        };
    }
}