// Package dumptsm inspects low-level details about tsm1 files.
package dumptsm

import (
	"encoding/binary"
	"flag"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
	"text/tabwriter"
	"time"

	"github.com/influxdata/influxdb/tsdb/engine/tsm1"
	"golang.org/x/text/cases"
	"golang.org/x/text/language"
)

// Command represents the program execution for "influxd dumptsm".
type Command struct {
	// Standard input/output, overridden for testing.
	Stderr io.Writer
	Stdout io.Writer

	dumpIndex  bool
	dumpBlocks bool
	dumpAll    bool
	filterKey  string
	path       string
}

// NewCommand returns a new instance of Command.
func NewCommand() *Command {
	return &Command{
		Stderr: os.Stderr,
		Stdout: os.Stdout,
	}
}

// Run executes the command.
func (cmd *Command) Run(args ...string) error {
	fs := flag.NewFlagSet("file", flag.ExitOnError)
	fs.BoolVar(&cmd.dumpIndex, "index", false, "Dump raw index data")
	fs.BoolVar(&cmd.dumpBlocks, "blocks", false, "Dump raw block data")
	fs.BoolVar(&cmd.dumpAll, "all", false, "Dump all data. Caution: This may print a lot of information")
	fs.StringVar(&cmd.filterKey, "filter-key", "", "Only display index and block data match this key substring")

	fs.SetOutput(cmd.Stdout)
	fs.Usage = cmd.printUsage

	if err := fs.Parse(args); err != nil {
		return err
	}

	if fs.Arg(0) == "" {
		fmt.Printf("TSM file not specified\n\n")
		fs.Usage()
		return nil
	}
	cmd.path = fs.Args()[0]
	cmd.dumpBlocks = cmd.dumpBlocks || cmd.dumpAll || cmd.filterKey != ""
	cmd.dumpIndex = cmd.dumpIndex || cmd.dumpAll || cmd.filterKey != ""
	return cmd.dump()
}

func (cmd *Command) dump() error {
	var errors []error

	f, err := os.Open(cmd.path)
	if err != nil {
		return err
	}

	// Get the file size
	stat, err := f.Stat()
	if err != nil {
		return err
	}
	b := make([]byte, 8)

	r, err := tsm1.NewTSMReader(f)
	if err != nil {
		return fmt.Errorf("Error opening TSM files: %s", err.Error())
	}
	defer r.Close()

	minTime, maxTime := r.TimeRange()
	keyCount := r.KeyCount()

	blockStats := &blockStats{}

	println("Summary:")
	fmt.Printf("  File: %s\n", cmd.path)
	fmt.Printf("  Time Range: %s - %s\n",
		time.Unix(0, minTime).UTC().Format(time.RFC3339Nano),
		time.Unix(0, maxTime).UTC().Format(time.RFC3339Nano),
	)
	fmt.Printf("  Duration: %s ", time.Unix(0, maxTime).Sub(time.Unix(0, minTime)))
	fmt.Printf("  Series: %d ", keyCount)
	fmt.Printf("  File Size: %d\n", stat.Size())
	println()

	tw := tabwriter.NewWriter(cmd.Stdout, 8, 8, 1, '\t', 0)

	if cmd.dumpIndex {
		println("Index:")
		tw.Flush()
		println()

		fmt.Fprintln(tw, "  "+strings.Join([]string{"Pos", "Min Time", "Max Time", "Ofs", "Size", "Key", "Field"}, "\t"))
		var pos int
		for i := 0; i < keyCount; i++ {
			key, _ := r.KeyAt(i)
			for _, e := range r.Entries(key) {
				pos++
				split := strings.Split(string(key), "#!~#")

				// Possible corruption? Try to read as much as we can and point to the problem.
				measurement := split[0]
				field := split[1]

				if cmd.filterKey != "" && !strings.Contains(string(key), cmd.filterKey) {
					continue
				}
				fmt.Fprintln(tw, "  "+strings.Join([]string{
					strconv.FormatInt(int64(pos), 10),
					time.Unix(0, e.MinTime).UTC().Format(time.RFC3339Nano),
					time.Unix(0, e.MaxTime).UTC().Format(time.RFC3339Nano),
					strconv.FormatInt(int64(e.Offset), 10),
					strconv.FormatInt(int64(e.Size), 10),
					measurement,
					field,
				}, "\t"))
				tw.Flush()
			}
		}
	}

	tw = tabwriter.NewWriter(cmd.Stdout, 8, 8, 1, '\t', 0)
	fmt.Fprintln(tw, "  "+strings.Join([]string{"Blk", "Chk", "Ofs", "Len", "Type", "Min Time", "Points", "Enc [T/V]", "Len [T/V]"}, "\t"))

	// Starting at 5 because the magic number is 4 bytes + 1 byte version
	i := int64(5)
	var blockCount, pointCount, blockSize int64
	indexSize := r.IndexSize()

	// Start at the beginning and read every block
	for j := 0; j < keyCount; j++ {
		key, _ := r.KeyAt(j)
		for _, e := range r.Entries(key) {

			f.Seek(int64(e.Offset), 0)
			f.Read(b[:4])

			chksum := binary.BigEndian.Uint32(b[:4])

			buf := make([]byte, e.Size-4)
			f.Read(buf)

			blockSize += int64(e.Size)

			if cmd.filterKey != "" && !strings.Contains(string(key), cmd.filterKey) {
				i += blockSize
				blockCount++
				continue
			}

			blockType := buf[0]

			encoded := buf[1:]

			var v []tsm1.Value
			v, err := tsm1.DecodeBlock(buf, v)
			if err != nil {
				return err
			}
			startTime := time.Unix(0, v[0].UnixNano())

			pointCount += int64(len(v))

			// Length of the timestamp block
			tsLen, j := binary.Uvarint(encoded)

			// Unpack the timestamp bytes
			ts := encoded[int(j) : int(j)+int(tsLen)]

			// Unpack the value bytes
			values := encoded[int(j)+int(tsLen):]

			tsEncoding := timeEnc[int(ts[0]>>4)]
			vEncoding := encDescs[int(blockType+1)][values[0]>>4]

			typeDesc := blockTypes[blockType]

			blockStats.inc(0, ts[0]>>4)
			blockStats.inc(int(blockType+1), values[0]>>4)
			blockStats.size(len(buf))

			if cmd.dumpBlocks {
				fmt.Fprintln(tw, "  "+strings.Join([]string{
					strconv.FormatInt(blockCount, 10),
					strconv.FormatUint(uint64(chksum), 10),
					strconv.FormatInt(i, 10),
					strconv.FormatInt(int64(len(buf)), 10),
					typeDesc,
					startTime.UTC().Format(time.RFC3339Nano),
					strconv.FormatInt(int64(len(v)), 10),
					fmt.Sprintf("%s/%s", tsEncoding, vEncoding),
					fmt.Sprintf("%d/%d", len(ts), len(values)),
				}, "\t"))
			}

			i += blockSize
			blockCount++
		}
	}

	if cmd.dumpBlocks {
		println("Blocks:")
		tw.Flush()
		println()
	}

	var blockSizeAvg int64
	if blockCount > 0 {
		blockSizeAvg = blockSize / blockCount
	}
	fmt.Printf("Statistics\n")
	fmt.Printf("  Blocks:\n")
	fmt.Printf("    Total: %d Size: %d Min: %d Max: %d Avg: %d\n",
		blockCount, blockSize, blockStats.min, blockStats.max, blockSizeAvg)
	fmt.Printf("  Index:\n")
	fmt.Printf("    Total: %d Size: %d\n", blockCount, indexSize)
	fmt.Printf("  Points:\n")
	fmt.Printf("    Total: %d", pointCount)
	println()

	println("  Encoding:")
	for i, counts := range blockStats.counts {
		if len(counts) == 0 {
			continue
		}
		fmt.Printf("    %s: ", cases.Title(language.Und, cases.NoLower).String(fieldType[i]))
		for j, v := range counts {
			fmt.Printf("\t%s: %d (%d%%) ", encDescs[i][j], v, int(float64(v)/float64(blockCount)*100))
		}
		println()
	}
	fmt.Printf("  Compression:\n")
	fmt.Printf("    Per block: %0.2f bytes/point\n", float64(blockSize)/float64(pointCount))
	fmt.Printf("    Total: %0.2f bytes/point\n", float64(stat.Size())/float64(pointCount))

	if len(errors) > 0 {
		println()
		fmt.Printf("Errors (%d):\n", len(errors))
		for _, err := range errors {
			fmt.Printf("  * %v\n", err)
		}
		println()
		return fmt.Errorf("error count %d", len(errors))
	}
	return nil
}

// printUsage prints the usage message to STDERR.
func (cmd *Command) printUsage() {
	usage := `Dumps low-level details about tsm1 files.

Usage: influx_inspect dumptsm [flags] <path

    -index
            Dump raw index data
    -blocks
            Dump raw block data
    -all
            Dump all data. Caution: This may print a lot of information
    -filter-key <name>
            Only display index and block data match this key substring
`

	fmt.Fprintf(cmd.Stdout, usage)
}

var (
	fieldType = []string{
		"timestamp", "float", "int", "bool", "string", "unsigned",
	}
	blockTypes = []string{
		"float64", "int64", "bool", "string", "unsigned",
	}
	timeEnc = []string{
		"none", "s8b", "rle",
	}
	floatEnc = []string{
		"none", "gor",
	}
	intEnc = []string{
		"none", "s8b", "rle",
	}
	boolEnc = []string{
		"none", "bp",
	}
	stringEnc = []string{
		"none", "snpy",
	}
	unsignedEnc = []string{
		"none", "s8b", "rle",
	}
	encDescs = [][]string{
		timeEnc, floatEnc, intEnc, boolEnc, stringEnc, unsignedEnc,
	}
)

type blockStats struct {
	min, max int
	counts   [][]int
}

func (b *blockStats) inc(typ int, enc byte) {
	for len(b.counts) <= typ {
		b.counts = append(b.counts, []int{})
	}
	for len(b.counts[typ]) <= int(enc) {
		b.counts[typ] = append(b.counts[typ], 0)
	}
	b.counts[typ][enc]++
}

func (b *blockStats) size(sz int) {
	if b.min == 0 || sz < b.min {
		b.min = sz
	}
	if b.min == 0 || sz > b.max {
		b.max = sz
	}
}
