package http

import (
	"context"
	"fmt"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

	"forge.cadoles.com/Cadoles/go-proxy/wildcard"
	"forge.cadoles.com/cadoles/bouncer/internal/rule"
	"github.com/expr-lang/expr"
	"github.com/pkg/errors"
)

func setRequestHostFunc() expr.Option {
	return expr.Function(
		"set_host",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			host, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			r, ok := CtxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.Host = host

			return true, nil
		},
		new(func(context.Context, string) bool),
	)
}

func setRequestURLFunc() expr.Option {
	return expr.Function(
		"set_url",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			rawURL, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			url, err := url.Parse(rawURL)
			if err != nil {
				return false, errors.WithStack(err)
			}

			r, ok := CtxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.URL = url

			return true, nil
		},
		new(func(context.Context, string) bool),
	)
}

func addRequestHeaderFunc() expr.Option {
	return expr.Function(
		"add_header",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			name, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			value := formatValue(params[2])

			r, ok := CtxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.Header.Add(name, value)

			return true, nil
		},
		new(func(context.Context, string, string) bool),
	)
}

func setRequestHeaderFunc() expr.Option {
	return expr.Function(
		"set_header",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			name, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			value := formatValue(params[2])

			r, ok := CtxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.Header.Set(name, value)

			return true, nil
		},
		new(func(context.Context, string, string) bool),
	)
}

func delRequestHeadersFunc() expr.Option {
	return expr.Function(
		"del_headers",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			pattern, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			r, ok := CtxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			deleted := false

			for key := range r.Header {
				if !wildcard.Match(key, pattern) {
					continue
				}

				r.Header.Del(key)
				deleted = true
			}

			return deleted, nil
		},
		new(func(context.Context, string) bool),
	)
}

type CookieVar struct {
	Name     string        `expr:"name"`
	Value    string        `expr:"value"`
	Path     string        `expr:"path"`
	Domain   string        `expr:"domain"`
	Expires  time.Time     `expr:"expires"`
	MaxAge   int           `expr:"max_age"`
	Secure   bool          `expr:"secure"`
	HttpOnly bool          `expr:"http_only"`
	SameSite http.SameSite `expr:"same_site"`
}

func getRequestCookieFunc() expr.Option {
	return expr.Function(
		"get_cookie",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			name, err := rule.Assert[string](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			r, ok := CtxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			cookie, err := r.Cookie(name)
			if err != nil && !errors.Is(err, http.ErrNoCookie) {
				return nil, errors.WithStack(err)
			}

			if cookie == nil {
				return nil, nil
			}

			return CookieVar{
				Name:     cookie.Name,
				Value:    cookie.Value,
				Path:     cookie.Path,
				Domain:   cookie.Domain,
				Expires:  cookie.Expires,
				MaxAge:   cookie.MaxAge,
				Secure:   cookie.Secure,
				HttpOnly: cookie.HttpOnly,
				SameSite: cookie.SameSite,
			}, nil
		},
		new(func(context.Context, string) CookieVar),
	)
}

func addRequestCookieFunc() expr.Option {
	return expr.Function(
		"add_cookie",
		func(params ...any) (any, error) {
			ctx, err := rule.Assert[context.Context](params[0])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			values, err := rule.Assert[map[string]any](params[1])
			if err != nil {
				return nil, errors.WithStack(err)
			}

			cookie, err := cookieFrom(values)
			if err != nil {
				return nil, errors.WithStack(err)
			}

			r, ok := CtxRequest(ctx)
			if !ok {
				return nil, errors.New("could not find http request in context")
			}

			r.AddCookie(cookie)

			return true, nil
		},
		new(func(context.Context, map[string]any) bool),
	)
}

func cookieFrom(values map[string]any) (*http.Cookie, error) {
	cookie := &http.Cookie{}

	if name, ok := values["name"].(string); ok {
		cookie.Name = name
	}

	if value, ok := values["value"].(string); ok {
		cookie.Value = value
	}

	if domain, ok := values["domain"].(string); ok {
		cookie.Domain = domain
	}

	if path, ok := values["path"].(string); ok {
		cookie.Path = path
	}

	if httpOnly, ok := values["http_only"].(bool); ok {
		cookie.HttpOnly = httpOnly
	}

	if maxAge, ok := values["max_age"].(int); ok {
		cookie.MaxAge = maxAge
	}

	if secure, ok := values["secure"].(bool); ok {
		cookie.Secure = secure
	}

	if sameSite, ok := values["same_site"].(http.SameSite); ok {
		cookie.SameSite = sameSite
	} else if sameSite, ok := values["same_site"].(int); ok {
		cookie.SameSite = http.SameSite(sameSite)
	}

	if expires, ok := values["expires"].(time.Time); ok {
		cookie.Expires = expires
	} else if rawExpires, ok := values["expires"].(string); ok {
		expires, err := time.Parse(http.TimeFormat, rawExpires)
		if err != nil {
			return nil, errors.WithStack(err)
		}

		cookie.Expires = expires
	}

	return cookie, nil
}

func formatValue(v any) string {
	var value string
	switch v := v.(type) {
	case []string:
		value = strings.Join(v, ",")
	case time.Time:
		value = strconv.FormatInt(v.UTC().Unix(), 10)
	case time.Duration:
		value = strconv.FormatInt(int64(v.Seconds()), 10)
	default:
		value = fmt.Sprintf("%v", v)
	}
	return value
}