import { z } from "zod";
import {
    AI_PROVIDER_AUTH_TYPES,
    providerRequiresUpstreamUrl,
    type AiProviderAuthType,
    type AiProviderRoutingMode,
    type AiProviderType
} from "@server/lib/aiProviderDefaults";
import { AI_CAPABILITIES } from "@server/lib/aiCapabilities";

export const aiProviderTypeSchema = z.enum([
    "openai",
    "anthropic",
    "googleGemini",
    "vertexAi",
    "bedrock",
    "microsoftFoundry",
    "openRouter",
    "vercelAiGateway",
    "custom"
]);

export const aiAuthTypeSchema = z.enum(AI_PROVIDER_AUTH_TYPES);

export const aiRoutingModeSchema = z.enum(["url", "target"]);

export const aiCapabilitySchema = z.enum(AI_CAPABILITIES);

export const aiCapabilitiesSchema = z.array(aiCapabilitySchema);

const validHeaderName = /^[a-zA-Z0-9!#$%&'*+\-.^_`|~]+$/;
const validHeaderValue = /^[\t\x20-\x7E]*$/;
const templatePattern = /\{\{[^}]+\}\}/;

export const aiProviderHeadersSchema = z
    .array(z.strictObject({ name: z.string(), value: z.string() }))
    .nullable()
    .optional()
    .superRefine((headers, ctx) => {
        if (!headers) {
            return;
        }
        for (const [index, header] of headers.entries()) {
            if (!validHeaderName.test(header.name)) {
                ctx.addIssue({
                    code: "custom",
                    message:
                        "Header names may only contain valid HTTP token characters (letters, digits, and !#$%&'*+-.^_`|~).",
                    path: [index, "name"]
                });
            }
            if (!validHeaderValue.test(header.value)) {
                ctx.addIssue({
                    code: "custom",
                    message:
                        "Header values may only contain printable ASCII characters and horizontal whitespace.",
                    path: [index, "value"]
                });
            }
            if (
                templatePattern.test(header.name) ||
                templatePattern.test(header.value)
            ) {
                ctx.addIssue({
                    code: "custom",
                    message:
                        "Header names and values must not contain template expressions such as {{value}}.",
                    path: [index]
                });
            }
        }
    });

export function refineProviderUpstreamFields(
    data: {
        type: AiProviderType;
        upstreamUrl?: string | null;
        authType?: AiProviderAuthType | null;
        routingMode?: AiProviderRoutingMode | null;
        capabilities?: z.infer<typeof aiCapabilitiesSchema> | null;
    },
    ctx: z.RefinementCtx
) {
    const routingMode = data.routingMode ?? "url";

    if (data.type !== "custom" && routingMode === "target") {
        ctx.addIssue({
            code: "custom",
            message: "routingMode target is only allowed for custom providers",
            path: ["routingMode"]
        });
    }

    if (
        providerRequiresUpstreamUrl(data.type, routingMode) &&
        !data.upstreamUrl
    ) {
        ctx.addIssue({
            code: "custom",
            message: `upstreamUrl is required for ${data.type} providers`,
            path: ["upstreamUrl"]
        });
    }

    if (data.type === "custom") {
        const caps = data.capabilities;
        if (!caps || caps.length === 0) {
            ctx.addIssue({
                code: "custom",
                message:
                    "At least one capability is required for custom providers",
                path: ["capabilities"]
            });
        }
    }
}