package records

import (
	"bufio"
	"encoding/json"
	"errors"
	"io"
	"log"
	"math"
	"os"
	"strconv"
	"strings"

	"github.com/curusarn/resh/pkg/histlist"
	"github.com/mattn/go-shellwords"
)

// BaseRecord - common base for Record and FallbackRecord
type BaseRecord struct {
	// core
	CmdLine   string `json:"cmdLine"`
	ExitCode  int    `json:"exitCode"`
	Shell     string `json:"shell"`
	Uname     string `json:"uname"`
	SessionID string `json:"sessionId"`

	// posix
	Home  string `json:"home"`
	Lang  string `json:"lang"`
	LcAll string `json:"lcAll"`
	Login string `json:"login"`
	//Path     string `json:"path"`
	Pwd      string `json:"pwd"`
	PwdAfter string `json:"pwdAfter"`
	ShellEnv string `json:"shellEnv"`
	Term     string `json:"term"`

	// non-posix"`
	RealPwd      string `json:"realPwd"`
	RealPwdAfter string `json:"realPwdAfter"`
	Pid          int    `json:"pid"`
	SessionPID   int    `json:"sessionPid"`
	Host         string `json:"host"`
	Hosttype     string `json:"hosttype"`
	Ostype       string `json:"ostype"`
	Machtype     string `json:"machtype"`
	Shlvl        int    `json:"shlvl"`

	// before after
	TimezoneBefore string `json:"timezoneBefore"`
	TimezoneAfter  string `json:"timezoneAfter"`

	RealtimeBefore      float64 `json:"realtimeBefore"`
	RealtimeAfter       float64 `json:"realtimeAfter"`
	RealtimeBeforeLocal float64 `json:"realtimeBeforeLocal"`
	RealtimeAfterLocal  float64 `json:"realtimeAfterLocal"`

	RealtimeDuration          float64 `json:"realtimeDuration"`
	RealtimeSinceSessionStart float64 `json:"realtimeSinceSessionStart"`
	RealtimeSinceBoot         float64 `json:"realtimeSinceBoot"`
	//Logs []string      `json: "logs"`

	GitDir               string `json:"gitDir"`
	GitRealDir           string `json:"gitRealDir"`
	GitOriginRemote      string `json:"gitOriginRemote"`
	GitDirAfter          string `json:"gitDirAfter"`
	GitRealDirAfter      string `json:"gitRealDirAfter"`
	GitOriginRemoteAfter string `json:"gitOriginRemoteAfter"`
	MachineID            string `json:"machineId"`

	OsReleaseID         string `json:"osReleaseId"`
	OsReleaseVersionID  string `json:"osReleaseVersionId"`
	OsReleaseIDLike     string `json:"osReleaseIdLike"`
	OsReleaseName       string `json:"osReleaseName"`
	OsReleasePrettyName string `json:"osReleasePrettyName"`

	ReshUUID     string `json:"reshUuid"`
	ReshVersion  string `json:"reshVersion"`
	ReshRevision string `json:"reshRevision"`

	// records come in two parts (collect and postcollect)
	PartOne     bool `json:"partOne,omitempty"` // false => part two
	PartsMerged bool `json:"partsMerged"`
	// special flag -> not an actual record but an session end
	SessionExit bool `json:"sessionExit,omitempty"`

	// recall metadata
	Recalled          bool     `json:"recalled"`
	RecallHistno      int      `json:"recallHistno,omitempty"`
	RecallStrategy    string   `json:"recallStrategy,omitempty"`
	RecallActionsRaw  string   `json:"recallActionsRaw,omitempty"`
	RecallActions     []string `json:"recallActions,omitempty"`
	RecallLastCmdLine string   `json:"recallLastCmdLine"`

	// recall command
	RecallPrefix string `json:"recallPrefix,omitempty"`

	// added by sanitizatizer
	Sanitized bool `json:"sanitized,omitempty"`
	CmdLength int  `json:"cmdLength,omitempty"`
}

// Record representing single executed command with its metadata
type Record struct {
	BaseRecord

	Cols  string `json:"cols"`
	Lines string `json:"lines"`
}

// EnrichedRecord - record enriched with additional data
type EnrichedRecord struct {
	Record

	// enriching fields - added "later"
	Command             string   `json:"command"`
	FirstWord           string   `json:"firstWord"`
	Invalid             bool     `json:"invalid"`
	SeqSessionID        uint64   `json:"seqSessionId"`
	LastRecordOfSession bool     `json:"lastRecordOfSession"`
	DebugThisRecord     bool     `json:"debugThisRecord"`
	Errors              []string `json:"errors"`
	// SeqSessionID uint64 `json:"seqSessionId,omitempty"`
}

// FallbackRecord when record is too old and can't be parsed into regular Record
type FallbackRecord struct {
	BaseRecord
	// older version of the record where cols and lines are int

	Cols  int `json:"cols"`  // notice the int type
	Lines int `json:"lines"` // notice the int type
}

// SlimRecord used for recalling because unmarshalling record w/ 50+ fields is too slow
type SlimRecord struct {
	SessionID    string `json:"sessionId"`
	RecallHistno int    `json:"recallHistno,omitempty"`
	RecallPrefix string `json:"recallPrefix,omitempty"`

	// extra recall - we might use these in the future
	// Pwd string `json:"pwd"`
	// RealPwd string `json:"realPwd"`
	// GitDir          string `json:"gitDir"`
	// GitRealDir      string `json:"gitRealDir"`
	// GitOriginRemote string `json:"gitOriginRemote"`

}

// Convert from FallbackRecord to Record
func Convert(r *FallbackRecord) Record {
	return Record{
		BaseRecord: r.BaseRecord,
		// these two lines are the only reason we are doing this
		Cols:  strconv.Itoa(r.Cols),
		Lines: strconv.Itoa(r.Lines),
	}
}

// ToString - returns record the json
func (r EnrichedRecord) ToString() (string, error) {
	jsonRec, err := json.Marshal(r)
	if err != nil {
		return "marshalling error", err
	}
	return string(jsonRec), nil
}

// Enriched - returnd enriched record
func Enriched(r Record) EnrichedRecord {
	record := EnrichedRecord{Record: r}
	// Get command/first word from commandline
	var err error
	record.Command, record.FirstWord, err = GetCommandAndFirstWord(r.CmdLine)
	if err != nil {
		record.Errors = append(record.Errors, "GetCommandAndFirstWord error:"+err.Error())
		// rec, _ := record.ToString()
		// log.Println("Invalid command:", rec)
		record.Invalid = true
		return record
	}
	err = r.Validate()
	if err != nil {
		record.Errors = append(record.Errors, "Validate error:"+err.Error())
		// rec, _ := record.ToString()
		// log.Println("Invalid command:", rec)
		record.Invalid = true
	}
	record.GitOriginRemote = NormalizeGitRemote(record.GitOriginRemote)
	return record
	// TODO: Detect and mark simple commands r.Simple
}

// Merge two records (part1 - collect + part2 - postcollect)
func (r *Record) Merge(r2 Record) error {
	if r.PartOne == false || r2.PartOne {
		return errors.New("Expected part1 and part2 of the same record - usage: part1.Merge(part2)")
	}
	if r.SessionID != r2.SessionID {
		return errors.New("Records to merge are not from the same sesion - r1:" + r.SessionID + " r2:" + r2.SessionID)
	}
	if r.CmdLine != r2.CmdLine {
		return errors.New("Records to merge are not parts of the same records - r1:" + r.CmdLine + " r2:" + r2.CmdLine)
	}
	// r.RealtimeBefore != r2.RealtimeBefore - can't be used because of bash-preexec runs when it's not supposed to
	r.ExitCode = r2.ExitCode
	r.PwdAfter = r2.PwdAfter
	r.RealPwdAfter = r2.RealPwdAfter
	r.GitDirAfter = r2.GitDirAfter
	r.GitRealDirAfter = r2.GitRealDirAfter
	r.RealtimeAfter = r2.RealtimeAfter
	r.GitOriginRemoteAfter = r2.GitOriginRemoteAfter
	r.TimezoneAfter = r2.TimezoneAfter
	r.RealtimeAfterLocal = r2.RealtimeAfterLocal
	r.RealtimeDuration = r2.RealtimeDuration

	r.PartsMerged = true
	r.PartOne = false
	return nil
}

// Validate - returns error if the record is invalid
func (r *Record) Validate() error {
	if r.CmdLine == "" {
		return errors.New("There is no CmdLine")
	}
	if r.RealtimeBefore == 0 || r.RealtimeAfter == 0 {
		return errors.New("There is no Time")
	}
	if r.RealtimeBeforeLocal == 0 || r.RealtimeAfterLocal == 0 {
		return errors.New("There is no Local Time")
	}
	if r.RealPwd == "" || r.RealPwdAfter == "" {
		return errors.New("There is no Real Pwd")
	}
	if r.Pwd == "" || r.PwdAfter == "" {
		return errors.New("There is no Pwd")
	}

	// TimezoneBefore
	// TimezoneAfter

	// RealtimeDuration
	// RealtimeSinceSessionStart - TODO: add later
	// RealtimeSinceBoot  - TODO: add later

	// device extras
	// Host
	// Hosttype
	// Ostype
	// Machtype
	// OsReleaseID
	// OsReleaseVersionID
	// OsReleaseIDLike
	// OsReleaseName
	// OsReleasePrettyName

	// session extras
	// Term
	// Shlvl

	// static info
	// Lang
	// LcAll

	// meta
	// ReshUUID
	// ReshVersion
	// ReshRevision

	// added by sanitizatizer
	// Sanitized
	// CmdLength
	return nil
}

// SetCmdLine sets cmdLine and related members
func (r *EnrichedRecord) SetCmdLine(cmdLine string) {
	r.CmdLine = cmdLine
	r.CmdLength = len(cmdLine)
	r.ExitCode = 0
	var err error
	r.Command, r.FirstWord, err = GetCommandAndFirstWord(cmdLine)
	if err != nil {
		r.Errors = append(r.Errors, "GetCommandAndFirstWord error:"+err.Error())
		// log.Println("Invalid command:", r.CmdLine)
		r.Invalid = true
	}
}

// Stripped returns record stripped of all info that is not available during prediction
func Stripped(r EnrichedRecord) EnrichedRecord {
	// clear the cmd itself
	r.SetCmdLine("")
	// replace after info with before info
	r.PwdAfter = r.Pwd
	r.RealPwdAfter = r.RealPwd
	r.TimezoneAfter = r.TimezoneBefore
	r.RealtimeAfter = r.RealtimeBefore
	r.RealtimeAfterLocal = r.RealtimeBeforeLocal
	// clear some more stuff
	r.RealtimeDuration = 0
	r.LastRecordOfSession = false
	return r
}

// GetCommandAndFirstWord func
func GetCommandAndFirstWord(cmdLine string) (string, string, error) {
	args, err := shellwords.Parse(cmdLine)
	if err != nil {
		// log.Println("shellwords Error:", err, " (cmdLine: <", cmdLine, "> )")
		return "", "", err
	}
	if len(args) == 0 {
		return "", "", nil
	}
	i := 0
	for true {
		// commands in shell sometimes look like this `variable=something command argument otherArgument --option`
		//		to get the command we skip over tokens that contain '='
		if strings.ContainsRune(args[i], '=') && len(args) > i+1 {
			i++
			continue
		}
		return args[i], args[0], nil
	}
	log.Fatal("GetCommandAndFirstWord error: this should not happen!")
	return "ERROR", "ERROR", errors.New("this should not happen - contact developer ;)")
}

// NormalizeGitRemote func
func NormalizeGitRemote(gitRemote string) string {
	if strings.HasSuffix(gitRemote, ".git") {
		return gitRemote[:len(gitRemote)-4]
	}
	return gitRemote
}

// DistParams is used to supply params to Enrichedrecords.DistanceTo()
type DistParams struct {
	ExitCode  float64
	MachineID float64
	SessionID float64
	Login     float64
	Shell     float64
	Pwd       float64
	RealPwd   float64
	Git       float64
	Time      float64
}

// DistanceTo another record
func (r *EnrichedRecord) DistanceTo(r2 EnrichedRecord, p DistParams) float64 {
	var dist float64
	dist = 0

	// lev distance or something? TODO later
	// CmdLine

	// exit code
	if r.ExitCode != r2.ExitCode {
		if r.ExitCode == 0 || r2.ExitCode == 0 {
			// one success + one error -> 1
			dist += 1 * p.ExitCode
		} else {
			// two different errors
			dist += 0.5 * p.ExitCode
		}
	}

	// machine/device
	if r.MachineID != r2.MachineID {
		dist += 1 * p.MachineID
	}
	// Uname

	// session
	if r.SessionID != r2.SessionID {
		dist += 1 * p.SessionID
	}
	// Pid - add because of nested shells?
	// SessionPid

	// user
	if r.Login != r2.Login {
		dist += 1 * p.Login
	}
	// Home

	// shell
	if r.Shell != r2.Shell {
		dist += 1 * p.Shell
	}
	// ShellEnv

	// pwd
	if r.Pwd != r2.Pwd {
		// TODO: compare using hierarchy
		// TODO: make more important
		dist += 1 * p.Pwd
	}
	if r.RealPwd != r2.RealPwd {
		// TODO: -||-
		dist += 1 * p.RealPwd
	}
	// PwdAfter
	// RealPwdAfter

	// git
	if r.GitDir != r2.GitDir {
		dist += 1 * p.Git
	}
	if r.GitRealDir != r2.GitRealDir {
		dist += 1 * p.Git
	}
	if r.GitOriginRemote != r2.GitOriginRemote {
		dist += 1 * p.Git
	}

	// time
	// this can actually get negative for differences of less than one second which is fine
	// distance grows by 1 with every order
	distTime := math.Log10(math.Abs(r.RealtimeBefore-r2.RealtimeBefore)) * p.Time
	if math.IsNaN(distTime) == false && math.IsInf(distTime, 0) == false {
		dist += distTime
	}
	// RealtimeBeforeLocal
	// RealtimeAfter
	// RealtimeAfterLocal

	// TimezoneBefore
	// TimezoneAfter

	// RealtimeDuration
	// RealtimeSinceSessionStart - TODO: add later
	// RealtimeSinceBoot  - TODO: add later

	// device extras
	// Host
	// Hosttype
	// Ostype
	// Machtype
	// OsReleaseID
	// OsReleaseVersionID
	// OsReleaseIDLike
	// OsReleaseName
	// OsReleasePrettyName

	// session extras
	// Term
	// Shlvl

	// static info
	// Lang
	// LcAll

	// meta
	// ReshUUID
	// ReshVersion
	// ReshRevision

	// added by sanitizatizer
	// Sanitized
	// CmdLength

	return dist
}

// LoadFromFile loads records from 'fname' file
func LoadFromFile(fname string, limit int) []Record {
	const allowedErrors = 1
	var encounteredErrors int
	// NOTE: limit does nothing atm
	var recs []Record
	file, err := os.Open(fname)
	if err != nil {
		log.Println("Open() resh history file error:", err)
		log.Println("WARN: Skipping reading resh history!")
		return recs
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	var i int
	var firstErrLine int
	for scanner.Scan() {
		i++
		record := Record{}
		fallbackRecord := FallbackRecord{}
		line := scanner.Text()
		err = json.Unmarshal([]byte(line), &record)
		if err != nil {
			err = json.Unmarshal([]byte(line), &fallbackRecord)
			if err != nil {
				if encounteredErrors == 0 {
					firstErrLine = i
				}
				encounteredErrors++
				log.Println("Line:", line)
				log.Println("Decoding error:", err)
				if encounteredErrors > allowedErrors {
					log.Fatalf("Fatal: Encountered more than %d decoding errors (%d)", allowedErrors, encounteredErrors)
				}
			}
			record = Convert(&fallbackRecord)
		}
		recs = append(recs, record)
	}
	if encounteredErrors > 0 {
		// fix errors in the history file
		log.Printf("There were %d decoding errors, the first error happend on line %d/%d", encounteredErrors, firstErrLine, i)
		log.Println("Backing up current history file ...")
		err := copyFile(fname, fname+".bak")
		if err != nil {
			log.Fatalln("Failed to backup history file with decode errors")
		}
		log.Println("Writing out a history file without errors ...")
		err = writeHistory(fname, recs)
		if err != nil {
			log.Fatalln("Fatal: Failed write out new history")
		}
	}
	return recs
}

func copyFile(source, dest string) error {
	from, err := os.Open(source)
	if err != nil {
		// log.Println("Open() resh history file error:", err)
		return err
	}
	defer from.Close()

	// to, err := os.OpenFile(dest, os.O_RDWR|os.O_CREATE, 0666)
	to, err := os.Create(dest)
	if err != nil {
		// log.Println("Create() resh history backup error:", err)
		return err
	}
	defer to.Close()

	_, err = io.Copy(to, from)
	if err != nil {
		// log.Println("Copy() resh history to backup error:", err)
		return err
	}
	return nil
}

func writeHistory(fname string, history []Record) error {
	file, err := os.Create(fname)
	if err != nil {
		// log.Println("Create() resh history error:", err)
		return err
	}
	defer file.Close()
	for _, rec := range history {
		jsn, err := json.Marshal(rec)
		if err != nil {
			log.Fatalln("Encode error!")
		}
		file.Write(append(jsn, []byte("\n")...))
	}
	return nil
}

// LoadCmdLinesFromZshFile loads cmdlines from zsh history file
func LoadCmdLinesFromZshFile(fname string) histlist.Histlist {
	hl := histlist.New()
	file, err := os.Open(fname)
	if err != nil {
		log.Println("Open() zsh history file error:", err)
		log.Println("WARN: Skipping reading zsh history!")
		return hl
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		// trim newline
		line = strings.TrimRight(line, "\n")
		var cmd string
		// zsh format EXTENDED_HISTORY
		// : 1576270617:0;make install
		// zsh format no EXTENDED_HISTORY
		// make install
		if len(line) == 0 {
			// skip empty
			continue
		}
		if strings.Contains(line, ":") && strings.Contains(line, ";") &&
			len(strings.Split(line, ":")) >= 3 && len(strings.Split(line, ";")) >= 2 {
			// contains at least 2x ':' and 1x ';' => assume EXTENDED_HISTORY
			cmd = strings.Split(line, ";")[1]
		} else {
			cmd = line
		}
		hl.AddCmdLine(cmd)
	}
	return hl
}

// LoadCmdLinesFromBashFile loads cmdlines from bash history file
func LoadCmdLinesFromBashFile(fname string) histlist.Histlist {
	hl := histlist.New()
	file, err := os.Open(fname)
	if err != nil {
		log.Println("Open() bash history file error:", err)
		log.Println("WARN: Skipping reading bash history!")
		return hl
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := scanner.Text()
		// trim newline
		line = strings.TrimRight(line, "\n")
		// trim spaces from left
		line = strings.TrimLeft(line, " ")
		// bash format (two lines)
		// #1576199174
		// make install
		if strings.HasPrefix(line, "#") {
			// is either timestamp or comment => skip
			continue
		}
		if len(line) == 0 {
			// skip empty
			continue
		}
		hl.AddCmdLine(line)
	}
	return hl
}