// Copyright 2018 gf Author(https://github.com/gogf/gf). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.

package ghttp

import (
	"reflect"
	"strings"

	"github.com/gogf/gf/text/gstr"

	"github.com/gogf/gf/util/gconv"
)

type (
	// RouterGroup is a group wrapping multiple routes and middleware.
	RouterGroup struct {
		parent     *RouterGroup  // Parent group.
		server     *Server       // Server.
		domain     *Domain       // Domain.
		prefix     string        // Prefix for sub-route.
		middleware []HandlerFunc // Middleware array.
	}

	// GroupItem is item for router group.
	GroupItem = []interface{}

	// preBindItem is item for lazy registering feature of router group. preBindItem is not really registered
	// to server when route function of the group called but is lazily registered when server starts.
	preBindItem struct {
		group    *RouterGroup
		bindType string
		pattern  string
		object   interface{}   // Can be handler, controller or object.
		params   []interface{} // Extra parameters for route registering depending on the type.
	}
)

var (
	preBindItems = make([]preBindItem, 0, 64)
)

// handlePreBindItems is called when server starts, which does really route registering to the server.
func (s *Server) handlePreBindItems() {
	for _, item := range preBindItems {
		// Handle the items of current server.
		if item.group.server != nil && item.group.server != s {
			continue
		}
		if item.group.domain != nil && item.group.domain.s != s {
			continue
		}
		item.group.doBind(item.bindType, item.pattern, item.object, item.params...)
	}
}

// Group creates and returns a RouterGroup object.
func (s *Server) Group(prefix string, groups ...func(group *RouterGroup)) *RouterGroup {
	if len(prefix) > 0 && prefix[0] != '/' {
		prefix = "/" + prefix
	}
	if prefix == "/" {
		prefix = ""
	}
	group := &RouterGroup{
		server: s,
		prefix: prefix,
	}
	if len(groups) > 0 {
		for _, v := range groups {
			v(group)
		}
	}
	return group
}

// Group creates and returns a RouterGroup object, which is bound to a specified domain.
func (d *Domain) Group(prefix string, groups ...func(group *RouterGroup)) *RouterGroup {
	if len(prefix) > 0 && prefix[0] != '/' {
		prefix = "/" + prefix
	}
	if prefix == "/" {
		prefix = ""
	}
	group := &RouterGroup{
		domain: d,
		prefix: prefix,
	}
	if len(groups) > 0 {
		for _, v := range groups {
			v(group)
		}
	}
	return group
}

// Group creates and returns a sub-group of current router group.
func (g *RouterGroup) Group(prefix string, groups ...func(group *RouterGroup)) *RouterGroup {
	if prefix == "/" {
		prefix = ""
	}
	group := &RouterGroup{
		parent: g,
		server: g.server,
		domain: g.domain,
		prefix: prefix,
	}
	if len(g.middleware) > 0 {
		group.middleware = make([]HandlerFunc, len(g.middleware))
		copy(group.middleware, g.middleware)
	}
	if len(groups) > 0 {
		for _, v := range groups {
			v(group)
		}
	}
	return group
}

// Clone returns a new router group which is a clone of current group.
func (g *RouterGroup) Clone() *RouterGroup {
	newGroup := &RouterGroup{
		parent:     g.parent,
		server:     g.server,
		domain:     g.domain,
		prefix:     g.prefix,
		middleware: make([]HandlerFunc, len(g.middleware)),
	}
	copy(newGroup.middleware, g.middleware)
	return newGroup
}

// Bind does batch route registering feature for router group.
func (g *RouterGroup) Bind(items []GroupItem) *RouterGroup {
	group := g.Clone()
	for _, item := range items {
		if len(item) < 3 {
			g.server.Logger().Fatalf("invalid router item: %s", item)
		}
		bindType := gstr.ToUpper(gconv.String(item[0]))
		switch bindType {
		case "REST":
			group.preBind("REST", gconv.String(item[0])+":"+gconv.String(item[1]), item[2])
		case "MIDDLEWARE":
			group.preBind("MIDDLEWARE", gconv.String(item[0])+":"+gconv.String(item[1]), item[2])
		default:
			if strings.EqualFold(bindType, "ALL") {
				bindType = ""
			} else {
				bindType += ":"
			}
			if len(item) > 3 {
				group.preBind("HANDLER", bindType+gconv.String(item[1]), item[2], item[3])
			} else {
				group.preBind("HANDLER", bindType+gconv.String(item[1]), item[2])
			}
		}
	}
	return group
}

// ALL registers a http handler to given route pattern and all http methods.
func (g *RouterGroup) ALL(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", gDEFAULT_METHOD+":"+pattern, object, params...)
}

// GET registers a http handler to given route pattern and http method: GET.
func (g *RouterGroup) GET(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "GET:"+pattern, object, params...)
}

// PUT registers a http handler to given route pattern and http method: PUT.
func (g *RouterGroup) PUT(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "PUT:"+pattern, object, params...)
}

// POST registers a http handler to given route pattern and http method: POST.
func (g *RouterGroup) POST(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "POST:"+pattern, object, params...)
}

// DELETE registers a http handler to given route pattern and http method: DELETE.
func (g *RouterGroup) DELETE(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "DELETE:"+pattern, object, params...)
}

// PATCH registers a http handler to given route pattern and http method: PATCH.
func (g *RouterGroup) PATCH(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "PATCH:"+pattern, object, params...)
}

// HEAD registers a http handler to given route pattern and http method: HEAD.
func (g *RouterGroup) HEAD(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "HEAD:"+pattern, object, params...)
}

// CONNECT registers a http handler to given route pattern and http method: CONNECT.
func (g *RouterGroup) CONNECT(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "CONNECT:"+pattern, object, params...)
}

// OPTIONS registers a http handler to given route pattern and http method: OPTIONS.
func (g *RouterGroup) OPTIONS(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "OPTIONS:"+pattern, object, params...)
}

// TRACE registers a http handler to given route pattern and http method: TRACE.
func (g *RouterGroup) TRACE(pattern string, object interface{}, params ...interface{}) *RouterGroup {
	return g.Clone().preBind("HANDLER", "TRACE:"+pattern, object, params...)
}

// REST registers a http handler to given route pattern according to REST rule.
func (g *RouterGroup) REST(pattern string, object interface{}) *RouterGroup {
	return g.Clone().preBind("REST", pattern, object)
}

// Hook registers a hook to given route pattern.
func (g *RouterGroup) Hook(pattern string, hook string, handler HandlerFunc) *RouterGroup {
	return g.Clone().preBind("HANDLER", pattern, handler, hook)
}

// Middleware binds one or more middleware to the router group.
func (g *RouterGroup) Middleware(handlers ...HandlerFunc) *RouterGroup {
	g.middleware = append(g.middleware, handlers...)
	return g
}

// preBind adds the route registering parameters to internal variable array for lazily registering feature.
func (g *RouterGroup) preBind(bindType string, pattern string, object interface{}, params ...interface{}) *RouterGroup {
	preBindItems = append(preBindItems, preBindItem{
		group:    g,
		bindType: bindType,
		pattern:  pattern,
		object:   object,
		params:   params,
	})
	return g
}

// getPrefix returns the route prefix of the group, which recursively retrieves its parent's prefixo.
func (g *RouterGroup) getPrefix() string {
	prefix := g.prefix
	parent := g.parent
	for parent != nil {
		prefix = parent.prefix + prefix
		parent = parent.parent
	}
	return prefix
}

// doBind does really registering for the group.
func (g *RouterGroup) doBind(bindType string, pattern string, object interface{}, params ...interface{}) *RouterGroup {
	prefix := g.getPrefix()
	// Route check.
	if len(prefix) > 0 {
		domain, method, path, err := g.server.parsePattern(pattern)
		if err != nil {
			g.server.Logger().Fatalf("invalid pattern: %s", pattern)
		}
		// If there'a already a domain, unset the domain field in the pattern.
		if g.domain != nil {
			domain = ""
		}
		if bindType == "REST" {
			pattern = prefix + "/" + strings.TrimLeft(path, "/")
		} else {
			pattern = g.server.serveHandlerKey(method, prefix+"/"+strings.TrimLeft(path, "/"), domain)
		}
	}
	// Filter repeated char '/'.
	pattern = gstr.Replace(pattern, "//", "/")
	// Convert params to string array.
	extras := gconv.Strings(params)
	// Check whether it's a hook handler.
	if _, ok := object.(HandlerFunc); ok && len(extras) > 0 {
		bindType = "HOOK"
	}
	switch bindType {
	case "HANDLER":
		if h, ok := object.(HandlerFunc); ok {
			if g.server != nil {
				g.server.doBindHandler(pattern, h, g.middleware)
			} else {
				g.domain.doBindHandler(pattern, h, g.middleware)
			}
		} else if g.isController(object) {
			if len(extras) > 0 {
				if g.server != nil {
					g.server.doBindControllerMethod(pattern, object.(Controller), extras[0], g.middleware)
				} else {
					g.domain.doBindControllerMethod(pattern, object.(Controller), extras[0], g.middleware)
				}
			} else {
				if g.server != nil {
					g.server.doBindController(pattern, object.(Controller), "", g.middleware)
				} else {
					g.domain.doBindController(pattern, object.(Controller), "", g.middleware)
				}
			}
		} else {
			if len(extras) > 0 {
				if g.server != nil {
					g.server.doBindObjectMethod(pattern, object, extras[0], g.middleware)
				} else {
					g.domain.doBindObjectMethod(pattern, object, extras[0], g.middleware)
				}
			} else {
				if g.server != nil {
					g.server.doBindObject(pattern, object, "", g.middleware)
				} else {
					g.domain.doBindObject(pattern, object, "", g.middleware)
				}
			}
		}
	case "REST":
		if g.isController(object) {
			if g.server != nil {
				g.server.doBindControllerRest(pattern, object.(Controller), g.middleware)
			} else {
				g.domain.doBindControllerRest(pattern, object.(Controller), g.middleware)
			}
		} else {
			if g.server != nil {
				g.server.doBindObjectRest(pattern, object, g.middleware)
			} else {
				g.domain.doBindObjectRest(pattern, object, g.middleware)
			}
		}
	case "HOOK":
		if h, ok := object.(HandlerFunc); ok {
			if g.server != nil {
				g.server.BindHookHandler(pattern, extras[0], h)
			} else {
				g.domain.BindHookHandler(pattern, extras[0], h)
			}
		} else {
			g.server.Logger().Fatalf("invalid hook handler for pattern:%s", pattern)
		}
	}
	return g
}

// isController checks and returns whether given <value> is a controller.
// A controller should contains attributes: Request/Response/Server/Cookie/Session/View.
func (g *RouterGroup) isController(value interface{}) bool {
	// Whether implements interface Controller.
	if _, ok := value.(Controller); !ok {
		return false
	}
	// Check the necessary attributes.
	v := reflect.ValueOf(value)
	if v.Kind() == reflect.Ptr {
		v = v.Elem()
	}
	if v.FieldByName("Request").IsValid() &&
		v.FieldByName("Response").IsValid() &&
		v.FieldByName("Server").IsValid() &&
		v.FieldByName("Cookie").IsValid() &&
		v.FieldByName("Session").IsValid() &&
		v.FieldByName("View").IsValid() {
		return true
	}
	return false
}