import { compress } from '../compress.js';
import { GQL_ENUM, GQL_TEMPLATE, isGqlEnum, isGqlFragment, isGqlTemplate, isGqlVariable } from './symbols.js';
import type { GqlEnum } from './enum.js';
import type { GqlFragment } from './fragment.js';
import type { TemplateStringsArrayLike } from './template-string.js';
import type { GqlVariable } from './variable.js';

/** GQL 模板可填充的类型 */
export type GqlTemplateValue =
    null | string | number | boolean | bigint | GqlEnum | GqlVariable | GqlFragment | GqlTemplate | GqlTemplate[];

/** GQL 模板已处理的填充类型 */
export type GqlTemplateContent = string | GqlVariable | GqlFragment | GqlTemplate | GqlTemplate[];

/** GQL 模板 */
export interface GqlTemplate {
    /** 插值量 */
    [GQL_TEMPLATE]: readonly GqlTemplateContent[];
    /** 字面量 */
    parts: readonly string[];
}

/** 检查模板字符串 */
function checkTemplatePart(part: string): void {
    const fq = part.indexOf('"');
    const lq = part.lastIndexOf('"');
    if (fq >= 0 && fq === lq) {
        throw new Error(
            `Invalid GQL template, interpolation is not allowed in strings, instead of 
    \`input: "interpolate \${value}" \`
use
    \`input: \${\`interpolate \${value}\`} \``,
        );
    }
}

/** 构造插值变量 */
function stringify(value: unknown): string {
    if (value == null) return 'null';
    // eslint-disable-next-line @typescript-eslint/switch-exhaustiveness-check
    switch (typeof value) {
        case 'boolean':
        case 'number':
        case 'bigint':
            return value.toString();
        case 'string':
            return JSON.stringify(value);
        default:
        // "symbol" | "object" | "function"
    }
    if (isGqlEnum(value)) return value[GQL_ENUM];
    throw new Error(
        `Cannot stringify ${Object.prototype.toString.call(
            value,
        )} as GQL literal, please use GqlVariable() to wrap it as a GQL variable.`,
    );
}

/** 创建 GQL 模板 */
export function GqlTemplate(query: TemplateStringsArrayLike, args: readonly GqlTemplateValue[]): GqlTemplate {
    if (args.length + 1 !== query.raw.length) {
        throw new Error(`Query string length does not match args.`);
    }
    const parts: string[] = [];
    const interpolated: GqlTemplateContent[] = [];
    let index = 0;
    for (const part of query.raw) {
        checkTemplatePart(part);
        parts.push(compress(part));
        if (index < args.length) {
            const arg = args[index];
            if (isGqlVariable(arg)) {
                interpolated.push(arg);
            } else if (isGqlFragment(arg)) {
                interpolated.push(arg);
            } else if (isGqlTemplate(arg) || (Array.isArray(arg) && arg.every((item) => isGqlTemplate(item)))) {
                interpolated.push(arg);
            } else {
                interpolated.push(stringify(arg));
            }
        }
        index++;
    }
    return {
        [GQL_TEMPLATE]: interpolated,
        parts,
    };
}