// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2018 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package pushrules

import "encoding/json"

// PushActionType is the type of a PushAction
type PushActionType string

// The allowed push action types as specified in spec section 11.12.1.4.1.
const (
        ActionNotify     PushActionType = "notify"
        ActionDontNotify PushActionType = "dont_notify"
        ActionCoalesce   PushActionType = "coalesce"
        ActionSetTweak   PushActionType = "set_tweak"
)

// PushActionTweak is the type of the tweak in SetTweak push actions.
type PushActionTweak string

// The allowed tweak types as specified in spec section 11.12.1.4.1.1.
const (
        TweakSound     PushActionTweak = "sound"
        TweakHighlight PushActionTweak = "highlight"
)

// PushActionArray is an array of PushActions.
type PushActionArray []*PushAction

// PushActionArrayShould contains the important information parsed from a PushActionArray.
type PushActionArrayShould struct {
        // Whether or not the array contained a Notify, DontNotify or Coalesce action type.
        NotifySpecified bool
        // Whether or not the event in question should trigger a notification.
        Notify bool
        // Whether or not the event in question should be highlighted.
        Highlight bool

        // Whether or not the event in question should trigger a sound alert.
        PlaySound bool
        // The name of the sound to play if PlaySound is true.
        SoundName string
}

// Should parses this push action array and returns the relevant details wrapped in a PushActionArrayShould struct.
func (actions PushActionArray) Should() (should PushActionArrayShould) {
        for _, action := range actions {
                switch action.Action {
                case ActionNotify, ActionCoalesce:
                        should.Notify = true
                        should.NotifySpecified = true
                case ActionDontNotify:
                        should.Notify = false
                        should.NotifySpecified = true
                case ActionSetTweak:
                        switch action.Tweak {
                        case TweakHighlight:
                                var ok bool
                                should.Highlight, ok = action.Value.(bool)
                                if !ok {
                                        // Highlight value not specified, so assume true since the tweak is set.
                                        should.Highlight = true
                                }
                        case TweakSound:
                                should.SoundName = action.Value.(string)
                                should.PlaySound = len(should.SoundName) > 0
                        }
                }
        }
        return
}

// PushAction is a single action that should be triggered when receiving a message.
type PushAction struct {
        Action PushActionType
        Tweak  PushActionTweak
        Value  interface{}
}

// UnmarshalJSON parses JSON into this PushAction.
//
//  * If the JSON is a single string, the value is stored in the Action field.
//  * If the JSON is an object with the set_tweak field, Action will be set to
//    "set_tweak", Tweak will be set to the value of the set_tweak field and
//    and Value will be set to the value of the value field.
//  * In any other case, the function does nothing.
func (action *PushAction) UnmarshalJSON(raw []byte) error {
        var data interface{}

        err := json.Unmarshal(raw, &data)
        if err != nil {
                return err
        }

        switch val := data.(type) {
        case string:
                action.Action = PushActionType(val)
        case map[string]interface{}:
                tweak, ok := val["set_tweak"].(string)
                if ok {
                        action.Action = ActionSetTweak
                        action.Tweak = PushActionTweak(tweak)
                        action.Value, _ = val["value"]
                }
        }
        return nil
}

// MarshalJSON is the reverse of UnmarshalJSON()
func (action *PushAction) MarshalJSON() (raw []byte, err error) {
        if action.Action == ActionSetTweak {
                data := map[string]interface{}{
                        "set_tweak": action.Tweak,
                        "value":     action.Value,
                }
                return json.Marshal(&data)
        } else {
                data := string(action.Action)
                return json.Marshal(&data)
        }
}

// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2018 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package pushrules

import (
        "regexp"
        "strconv"
        "strings"

        "github.com/zyedidia/glob"
        "maunium.net/go/gomatrix"
        "maunium.net/go/gomuks/matrix/rooms"
)

// Room is an interface with the functions that are needed for processing room-specific push conditions
type Room interface {
        GetMember(mxid string) *rooms.Member
        GetMembers() map[string]*rooms.Member
        GetSessionOwner() *rooms.Member
}

// PushCondKind is the type of a push condition.
type PushCondKind string

// The allowed push condition kinds as specified in section 11.12.1.4.3 of r0.3.0 of the Client-Server API.
const (
        KindEventMatch          PushCondKind = "event_match"
        KindContainsDisplayName PushCondKind = "contains_display_name"
        KindRoomMemberCount     PushCondKind = "room_member_count"
)

// PushCondition wraps a condition that is required for a specific PushRule to be used.
type PushCondition struct {
        // The type of the condition.
        Kind PushCondKind `json:"kind"`
        // The dot-separated field of the event to match. Only applicable if kind is EventMatch.
        Key string `json:"key,omitempty"`
        // The glob-style pattern to match the field against. Only applicable if kind is EventMatch.
        Pattern string `json:"pattern,omitempty"`
        // The condition that needs to be fulfilled for RoomMemberCount-type conditions.
        // A decimal integer optionally prefixed by ==, <, >, >= or <=. Prefix "==" is assumed if no prefix found.
        MemberCountCondition string `json:"is,omitempty"`
}

// MemberCountFilterRegex is the regular expression to parse the MemberCountCondition of PushConditions.
var MemberCountFilterRegex = regexp.MustCompile("^(==|[<>]=?)?([0-9]+)$")

// Match checks if this condition is fulfilled for the given event in the given room.
func (cond *PushCondition) Match(room Room, event *gomatrix.Event) bool {
        switch cond.Kind {
        case KindEventMatch:
                return cond.matchValue(room, event)
        case KindContainsDisplayName:
                return cond.matchDisplayName(room, event)
        case KindRoomMemberCount:
                return cond.matchMemberCount(room, event)
        default:
                return false
        }
}

func (cond *PushCondition) matchValue(room Room, event *gomatrix.Event) bool {
        index := strings.IndexRune(cond.Key, '.')
        key := cond.Key
        subkey := ""
        if index > 0 {
                subkey = key[index+1:]
                key = key[0:index]
        }

        pattern, _ := glob.Compile(cond.Pattern)

        switch key {
        case "type":
                return pattern.MatchString(event.Type)
        case "sender":
                return pattern.MatchString(event.Sender)
        case "room_id":
                return pattern.MatchString(event.RoomID)
        case "state_key":
                if event.StateKey == nil {
                        return cond.Pattern == ""
                }
                return pattern.MatchString(*event.StateKey)
        case "content":
                val, _ := event.Content[subkey].(string)
                return pattern.MatchString(val)
        default:
                return false
        }
}

func (cond *PushCondition) matchDisplayName(room Room, event *gomatrix.Event) bool {
        member := room.GetSessionOwner()
        if member == nil || member.UserID == event.Sender {
                return false
        }
        text, _ := event.Content["body"].(string)
        return strings.Contains(text, member.DisplayName)
}

func (cond *PushCondition) matchMemberCount(room Room, event *gomatrix.Event) bool {
        group := MemberCountFilterRegex.FindStringSubmatch(cond.MemberCountCondition)
        if len(group) != 3 {
                return false
        }

        operator := group[1]
        wantedMemberCount, _ := strconv.Atoi(group[2])

        memberCount := len(room.GetMembers())

        switch operator {
        case "==", "":
                return memberCount == wantedMemberCount
        case ">":
                return memberCount > wantedMemberCount
        case ">=":
                return memberCount >= wantedMemberCount
        case "<":
                return memberCount < wantedMemberCount
        case "<=":
                return memberCount <= wantedMemberCount
        default:
                // Should be impossible due to regex.
                return false
        }
}

package pushrules

import (
        "encoding/json"
        "net/url"

        "maunium.net/go/gomatrix"
)

// GetPushRules returns the push notification rules for the global scope.
func GetPushRules(client *gomatrix.Client) (*PushRuleset, error) {
        return GetScopedPushRules(client, "global")
}

// GetScopedPushRules returns the push notification rules for the given scope.
func GetScopedPushRules(client *gomatrix.Client, scope string) (resp *PushRuleset, err error) {
        u, _ := url.Parse(client.BuildURL("pushrules", scope))
        // client.BuildURL returns the URL without a trailing slash, but the pushrules endpoint requires the slash.
        u.Path += "/"
        _, err = client.MakeRequest("GET", u.String(), nil, &resp)
        return
}

// EventToPushRules converts a m.push_rules event to a PushRuleset by passing the data through JSON.
func EventToPushRules(event *gomatrix.Event) (*PushRuleset, error) {
        content, _ := event.Content["global"]
        raw, err := json.Marshal(content)
        if err != nil {
                return nil, err
        }

        ruleset := &PushRuleset{}
        err = json.Unmarshal(raw, ruleset)
        if err != nil {
                return nil, err
        }

        return ruleset, nil
}

// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2018 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package pushrules

import (
        "github.com/zyedidia/glob"
        "maunium.net/go/gomatrix"
)

type PushRuleCollection interface {
        GetActions(room Room, event *gomatrix.Event) PushActionArray
}

type PushRuleArray []*PushRule

func (rules PushRuleArray) setType(typ PushRuleType) PushRuleArray {
        for _, rule := range rules {
                rule.Type = typ
        }
        return rules
}

func (rules PushRuleArray) GetActions(room Room, event *gomatrix.Event) PushActionArray {
        for _, rule := range rules {
                if !rule.Match(room, event) {
                        continue
                }
                return rule.Actions
        }
        return nil
}

type PushRuleMap struct {
        Map  map[string]*PushRule
        Type PushRuleType
}

func (rules PushRuleArray) setTypeAndMap(typ PushRuleType) PushRuleMap {
        data := PushRuleMap{
                Map:  make(map[string]*PushRule),
                Type: typ,
        }
        for _, rule := range rules {
                rule.Type = typ
                data.Map[rule.RuleID] = rule
        }
        return data
}

func (ruleMap PushRuleMap) GetActions(room Room, event *gomatrix.Event) PushActionArray {
        var rule *PushRule
        var found bool
        switch ruleMap.Type {
        case RoomRule:
                rule, found = ruleMap.Map[event.RoomID]
        case SenderRule:
                rule, found = ruleMap.Map[event.Sender]
        }
        if found && rule.Match(room, event) {
                return rule.Actions
        }
        return nil
}

func (ruleMap PushRuleMap) unmap() PushRuleArray {
        array := make(PushRuleArray, len(ruleMap.Map))
        index := 0
        for _, rule := range ruleMap.Map {
                array[index] = rule
                index++
        }
        return array
}

type PushRuleType string

const (
        OverrideRule  PushRuleType = "override"
        ContentRule   PushRuleType = "content"
        RoomRule      PushRuleType = "room"
        SenderRule    PushRuleType = "sender"
        UnderrideRule PushRuleType = "underride"
)

type PushRule struct {
        // The type of this rule.
        Type PushRuleType `json:"-"`
        // The ID of this rule.
        // For room-specific rules and user-specific rules, this is the room or user ID (respectively)
        // For other types of rules, this doesn't affect anything.
        RuleID string `json:"rule_id"`
        // The actions this rule should trigger when matched.
        Actions PushActionArray `json:"actions"`
        // Whether this is a default rule, or has been set explicitly.
        Default bool `json:"default"`
        // Whether or not this push rule is enabled.
        Enabled bool `json:"enabled"`
        // The conditions to match in order to trigger this rule.
        // Only applicable to generic underride/override rules.
        Conditions []*PushCondition `json:"conditions,omitempty"`
        // Pattern for content-specific push rules
        Pattern string `json:"pattern,omitempty"`
}

func (rule *PushRule) Match(room Room, event *gomatrix.Event) bool {
        if !rule.Enabled {
                return false
        }
        switch rule.Type {
        case OverrideRule, UnderrideRule:
                return rule.matchConditions(room, event)
        case ContentRule:
                return rule.matchPattern(room, event)
        case RoomRule:
                return rule.RuleID == event.RoomID
        case SenderRule:
                return rule.RuleID == event.Sender
        default:
                return false
        }
}

func (rule *PushRule) matchConditions(room Room, event *gomatrix.Event) bool {
        for _, cond := range rule.Conditions {
                if !cond.Match(room, event) {
                        return false
                }
        }
        return true
}

func (rule *PushRule) matchPattern(room Room, event *gomatrix.Event) bool {
        pattern, err := glob.Compile(rule.Pattern)
        if err != nil {
                return false
        }
        text, _ := event.Content["body"].(string)
        return pattern.MatchString(text)
}

// gomuks - A terminal Matrix client written in Go.
// Copyright (C) 2018 Tulir Asokan
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package pushrules

import (
        "encoding/json"

        "maunium.net/go/gomatrix"
)

type PushRuleset struct {
        Override  PushRuleArray
        Content   PushRuleArray
        Room      PushRuleMap
        Sender    PushRuleMap
        Underride PushRuleArray
}

type rawPushRuleset struct {
        Override  PushRuleArray `json:"override"`
        Content   PushRuleArray `json:"content"`
        Room      PushRuleArray `json:"room"`
        Sender    PushRuleArray `json:"sender"`
        Underride PushRuleArray `json:"underride"`
}

// UnmarshalJSON parses JSON into this PushRuleset.
//
// For override, sender and underride push rule arrays, the type is added
// to each PushRule and the array is used as-is.
//
// For room and sender push rule arrays, the type is added to each PushRule
// and the array is converted to a map with the rule ID as the key and the
// PushRule as the value.
func (rs *PushRuleset) UnmarshalJSON(raw []byte) (err error) {
        data := rawPushRuleset{}
        err = json.Unmarshal(raw, &data)
        if err != nil {
                return
        }

        rs.Override = data.Override.setType(OverrideRule)
        rs.Content = data.Content.setType(ContentRule)
        rs.Room = data.Room.setTypeAndMap(RoomRule)
        rs.Sender = data.Sender.setTypeAndMap(SenderRule)
        rs.Underride = data.Underride.setType(UnderrideRule)
        return
}

// MarshalJSON is the reverse of UnmarshalJSON()
func (rs *PushRuleset) MarshalJSON() ([]byte, error) {
        data := rawPushRuleset{
                Override:  rs.Override,
                Content:   rs.Content,
                Room:      rs.Room.unmap(),
                Sender:    rs.Sender.unmap(),
                Underride: rs.Underride,
        }
        return json.Marshal(&data)
}

// DefaultPushActions is the value returned if none of the rule
// collections in a Ruleset match the event given to GetActions()
var DefaultPushActions = make(PushActionArray, 0)

// GetActions matches the given event against all of the push rule
// collections in this push ruleset in the order of priority as
// specified in spec section 11.12.1.4.
func (rs *PushRuleset) GetActions(room Room, event *gomatrix.Event) (match PushActionArray) {
        // Add push rule collections to array in priority order
        arrays := []PushRuleCollection{rs.Override, rs.Content, rs.Room, rs.Sender, rs.Underride}
        // Loop until one of the push rule collections matches the room/event combo.
        for _, pra := range arrays {
                if match = pra.GetActions(room, event); match != nil {
                        // Match found, return it.
                        return
                }
        }
        // No match found, return default actions.
        return DefaultPushActions
}