const std = @import("std");
const zap = @import("zap");
const mem = std.mem;

fn sendJson(r: zap.Request, body: []const u8) void {
    r.setHeader("content-type", "application/json") catch {};
    r.setHeader("access-control-allow-origin", "*") catch {};
    r.setHeader("access-control-allow-methods", "GET, POST, PATCH, DELETE, OPTIONS") catch {};
    r.setHeader("access-control-allow-headers", "content-type, x-prefect-api-version") catch {};
    r.sendBody(body) catch {};
}

pub fn health(r: zap.Request) !void {
    // match python prefect server response
    r.setHeader("content-type", "text/plain") catch {};
    r.setHeader("access-control-allow-origin", "*") catch {};
    r.sendBody("ok") catch {};
}

pub fn csrfToken(r: zap.Request) !void {
    // prefect client expects a csrf token with client id and expiration
    // extract client from query string: /api/csrf-token?client=...
    const target = r.path orelse "/";
    var client_id: []const u8 = "unknown";

    if (mem.indexOf(u8, target, "client=")) |start| {
        const rest = target[start + 7 ..];
        if (mem.indexOf(u8, rest, "&")) |end| {
            client_id = rest[0..end];
        } else {
            client_id = rest;
        }
    }

    var buf: [512]u8 = undefined;
    const response = std.fmt.bufPrint(&buf,
        \\{{"token":"zig-csrf-token","client":"{s}","expiration":"2099-01-01T00:00:00Z"}}
    , .{client_id}) catch {
        sendJson(r, "{\"token\":\"zig-csrf-token\",\"client\":\"unknown\",\"expiration\":\"2099-01-01T00:00:00Z\"}");
        return;
    };
    sendJson(r, response);
}

pub fn version(r: zap.Request) !void {
    // return version as JSON string (FastAPI behavior)
    // must return 3.x to match Python client major version
    sendJson(r, "\"3.0.0\"");
}