package httpx

import (
	"log/slog"
	"net/http"
	"time"

	"git.codelab.vc/pkg/httpx/balancer"
	"git.codelab.vc/pkg/httpx/circuitbreaker"
	"git.codelab.vc/pkg/httpx/middleware"
	"git.codelab.vc/pkg/httpx/retry"
)

type clientOptions struct {
	baseURL         string
	timeout         time.Duration
	transport       http.RoundTripper
	logger          *slog.Logger
	errorMapper     ErrorMapper
	middlewares     []middleware.Middleware
	retryOpts       []retry.Option
	enableRetry     bool
	cbOpts          []circuitbreaker.Option
	enableCB        bool
	endpoints       []balancer.Endpoint
	balancerOpts    []balancer.Option
	maxResponseBody int64
}

// Option configures a Client.
type Option func(*clientOptions)

// WithBaseURL sets the base URL prepended to all relative request paths.
func WithBaseURL(url string) Option {
	return func(o *clientOptions) { o.baseURL = url }
}

// WithTimeout sets the overall request timeout.
func WithTimeout(d time.Duration) Option {
	return func(o *clientOptions) { o.timeout = d }
}

// WithTransport sets the base http.RoundTripper. Defaults to http.DefaultTransport.
func WithTransport(rt http.RoundTripper) Option {
	return func(o *clientOptions) { o.transport = rt }
}

// WithLogger enables structured logging of requests and responses.
func WithLogger(l *slog.Logger) Option {
	return func(o *clientOptions) { o.logger = l }
}

// WithErrorMapper sets a function that maps HTTP responses to errors.
func WithErrorMapper(m ErrorMapper) Option {
	return func(o *clientOptions) { o.errorMapper = m }
}

// WithMiddleware appends user middlewares to the chain.
// These run between logging and retry in the middleware stack.
func WithMiddleware(mws ...middleware.Middleware) Option {
	return func(o *clientOptions) { o.middlewares = append(o.middlewares, mws...) }
}

// WithRetry enables retry with the given options.
func WithRetry(opts ...retry.Option) Option {
	return func(o *clientOptions) {
		o.enableRetry = true
		o.retryOpts = opts
	}
}

// WithCircuitBreaker enables per-host circuit breaking.
func WithCircuitBreaker(opts ...circuitbreaker.Option) Option {
	return func(o *clientOptions) {
		o.enableCB = true
		o.cbOpts = opts
	}
}

// WithEndpoints sets the endpoints for load balancing.
func WithEndpoints(eps ...balancer.Endpoint) Option {
	return func(o *clientOptions) { o.endpoints = eps }
}

// WithBalancer configures the load balancer strategy and options.
func WithBalancer(opts ...balancer.Option) Option {
	return func(o *clientOptions) { o.balancerOpts = opts }
}

// WithMaxResponseBody limits the number of bytes read from response bodies
// by Response.Bytes (and by extension String, JSON, XML). If the response
// body exceeds n bytes, reading stops and returns an error.
// A value of 0 means no limit (the default).
func WithMaxResponseBody(n int64) Option {
	return func(o *clientOptions) { o.maxResponseBody = n }
}