/*
NAME
  psi_test.go
DESCRIPTION
  See Readme.md

AUTHOR
  Saxon Milton <saxon@ausocean.org>

LICENSE
  psi_test.go is Copyright (C) 2018 the Australian Ocean Lab (AusOcean)

  It is free software: you can redistribute it and/or modify them
  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.

  It 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 revid in gpl.txt.  If not, see http://www.gnu.org/licenses.
*/

package psi

import (
	"bytes"
	"testing"
)

// Some common manifestations of PSI
var (
	// standardPat is a minimal PAT.
	standardPat = PSI{
		Pf:  0x00,
		Tid: 0x00,
		Ssi: true,
		Pb:  false,
		Sl:  0x0d,
		Tss: &TSS{
			Tide: 0x01,
			V:    0,
			Cni:  true,
			Sn:   0,
			Lsn:  0,
			Sd: &PAT{
				Pn:    0x01,
				Pmpid: 0x1000,
			},
		},
	}

	// standardPmt is a minimal PMT, without time and location descriptors.
	standardPmt = PSI{
		Pf:  0x00,
		Tid: 0x02,
		Ssi: true,
		Sl:  0x12,
		Tss: &TSS{
			Tide: 0x01,
			V:    0,
			Cni:  true,
			Sn:   0,
			Lsn:  0,
			Sd: &PMT{
				Pcrpid: 0x0100, // wrong
				Pil:    0,
				Essd: &ESSD{
					St:   0x1b,
					Epid: 0x0100,
					Esil: 0x00,
				},
			},
		},
	}

	// standardPmtTimeLocation is a standard PMT with time and location
	// descriptors, but time and location fields zeroed out.
	standardPmtWithMeta = PSI{
		Pf:  0x00,
		Tid: 0x02,
		Ssi: true,
		Sl:  0x3e,
		Tss: &TSS{
			Tide: 0x01,
			V:    0,
			Cni:  true,
			Sn:   0,
			Lsn:  0,
			Sd: &PMT{
				Pcrpid: 0x0100,
				Pil:    PmtTimeLocationPil,
				Pd: []Desc{
					{
						Dt: TimeDescTag,
						Dl: TimeDataSize,
						Dd: make([]byte, TimeDataSize),
					},
					{
						Dt: LocationDescTag,
						Dl: LocationDataSize,
						Dd: make([]byte, LocationDataSize),
					},
				},
				Essd: &ESSD{
					St:   0x1b,
					Epid: 0x0100,
					Esil: 0x00,
				},
			},
		},
	}
)

// Times as ints for testing
const (
	tstTime1 = 1235367435 // 0x49a2360b
	tstTime2 = 1735357535 // 0x676f745f
)

// GPS string for testing
// TODO: make these realistic
const (
	locationTstStr1 = "$GPGGA,123519,4807.038,N,01131.0"
	locationTstStr2 = "$GPGGA,183710,4902.048,N,02171.0"
)

// err message
const (
	errCmp = "Incorrect output, for: %v \nwant: %v, \ngot:  %v"
)

// Test time to bytes test Data
var (
	timeSlice = []byte{
		0x00, 0x00, 0x00, 0x00, 0x49, 0xA2, 0x36, 0x0B,
	}
)

// Parts to construct bytes of pmt with time and bytes
var (
	pmtWithMetaHead = []byte{
		0x00, 0x02, 0xb0, 0x12, 0x00, 0x01, 0xc1, 0x00, 0x00, 0xe1, 0x00, 0xf0, 0x0a,
		TimeDescTag,                                    // Descriptor tag for timestamp
		TimeDataSize,                                   // Length of bytes to follow
		0x00, 0x00, 0x00, 0x00, 0x67, 0x6f, 0x74, 0x5f, // Timestamp data
		LocationDescTag,  // Descriptor tag for location
		LocationDataSize, // Length of bytes to follow
	}
	pmtWithMetaTail = []byte{
		0x1b, 0xe1, 0x00, 0xf0, 0x00,
	}
)

var (
	// Bytes representing pmt with tstTime1
	pmtTimeBytes1 = []byte{
		0x00, 0x02, 0xb0, 0x12, 0x00, 0x01, 0xc1, 0x00, 0x00, 0xe1, 0x00, 0xf0, 0x0a,
		TimeDescTag,                                    // Descriptor tag
		TimeDataSize,                                   // Length of bytes to follow
		0x00, 0x00, 0x00, 0x00, 0x49, 0xa2, 0x36, 0x0b, // timestamp
		0x1b, 0xe1, 0x00, 0xf0, 0x00,
	}

	// Bytes representing pmt with tstTime 2
	pmtTimeBytes2 = []byte{
		0x00, 0x02, 0xb0, 0x12, 0x00, 0x01, 0xc1, 0x00, 0x00, 0xe1, 0x00, 0xf0, 0x0a,
		TimeDescTag,                                    // Descriptor tag
		TimeDataSize,                                   // Length of bytes to follow
		0x00, 0x00, 0x00, 0x00, 0x67, 0x6f, 0x74, 0x5f, // timestamp
		0x1b, 0xe1, 0x00, 0xf0, 0x00,
	}

	// Bytes representing pmt with time1 and location1
	pmtWithMetaTst1 = buildPmtWithMeta(locationTstStr1)

	// bytes representing pmt with with time1 and location 2
	pmtWithMetaTst2 = buildPmtWithMeta(locationTstStr2)
)

// bytesTests contains data for testing the Bytes() funcs for the PSI data struct
var bytesTests = []struct {
	name  string
	input PSI
	want  []byte
}{
	// Pat test
	{
		name:  "pat Bytes()",
		input: standardPat,
		want:  StandardPatBytes,
	},

	// Pmt test data no descriptor
	{
		name:  "pmt to Bytes() without descriptors",
		input: standardPmt,
		want:  StandardPmtBytes,
	},

	// Pmt with time descriptor
	{
		name: "pmt to Bytes() with time descriptor",
		input: PSI{
			Pf:  0x00,
			Tid: 0x02,
			Ssi: true,
			Sl:  0x12,
			Tss: &TSS{
				Tide: 0x01,
				V:    0,
				Cni:  true,
				Sn:   0,
				Lsn:  0,
				Sd: &PMT{
					Pcrpid: 0x0100, // wrong
					Pil:    10,
					Pd: []Desc{
						{
							Dt: TimeDescTag,
							Dl: TimeDataSize,
							Dd: TimeBytes(tstTime1),
						},
					},
					Essd: &ESSD{
						St:   0x1b,
						Epid: 0x0100,
						Esil: 0x00,
					},
				},
			},
		},
		want: pmtTimeBytes1,
	},

	// Pmt with time and location
	{
		name: "pmt Bytes() with time and location",
		input: PSI{
			Pf:  0x00,
			Tid: 0x02,
			Ssi: true,
			Sl:  0x12,
			Tss: &TSS{
				Tide: 0x01,
				V:    0,
				Cni:  true,
				Sn:   0,
				Lsn:  0,
				Sd: &PMT{
					Pcrpid: 0x0100, // wrong
					Pil:    10,
					Pd: []Desc{
						{
							Dt: TimeDescTag,
							Dl: TimeDataSize,
							Dd: TimeBytes(tstTime2),
						},
						{
							Dt: LocationDescTag,
							Dl: LocationDataSize,
							Dd: []byte(locationTstStr1),
						},
					},
					Essd: &ESSD{
						St:   0x1b,
						Epid: 0x0100,
						Esil: 0x00,
					},
				},
			},
		},
		want: buildPmtWithMeta(locationTstStr1),
	},
}

// TestBytes ensures that the Bytes() funcs are working correctly to take PSI
// structs and convert them to byte slices
func TestBytes(t *testing.T) {
	for _, test := range bytesTests {
		got := test.input.Bytes()
		if !bytes.Equal(got, addPadding(addCrc(test.want))) {
			t.Errorf("unexpected error for test %v: got:%v want:%v", test.name, got,
				test.want)
		}
	}
}

// TestTimestampToBytes is a quick sanity check of the int64 time to []byte func
func TestTimestampToBytes(t *testing.T) {
	tb := TimeBytes(tstTime1)
	if !bytes.Equal(timeSlice, tb) {
		t.Errorf(errCmp, "testTimeStampToBytes", timeSlice, tb)
	}
}

// TestTimeUpdate checks to see if we can correctly update the timstamp in pmt
func TestTimeUpdate(t *testing.T) {
	cpy := make([]byte, len(pmtTimeBytes1))
	copy(cpy, pmtTimeBytes1)
	cpy = addCrc(cpy)
	err := UpdateTime(cpy, tstTime2)
	cpy = cpy[:len(cpy)-4]
	if err != nil {
		t.Errorf("Update time returned err: %v", err)
	}
	if !bytes.Equal(pmtTimeBytes2, cpy) {
		t.Errorf(errCmp, "TestTimeUpdate", pmtTimeBytes2, cpy)
	}
}

// TestTimeGet tsts to see if we can correctly get the timestamp from a pmt
func TestTimeGet(t *testing.T) {
	s, err := TimeFrom(pmtTimeBytes1)
	if err != nil {
		t.Errorf("Getting timestamp failed with err: %v", err)
	}
	if s != tstTime1 {
		t.Errorf(errCmp, "TestTimeGet", tstTime1, s)
	}
}

// TestLocationGet checks that we can correctly get location data from a pmt table
func TestLocationGet(t *testing.T) {
	pb := standardPmtWithMeta.Bytes()
	err := UpdateLocation(pb, locationTstStr1)
	if err != nil {
		t.Errorf("Error for TestLocationGet UpdateLocation(pb, locationTstStr1): %v", err)
	}
	g, err := LocationFrom(pb)
	if err != nil {
		t.Errorf("Error for TestLocationGet LocationOf(pb): %v", err)
	}
	if g != locationTstStr1 {
		t.Errorf(errCmp, "TestLocationGet", locationTstStr1, g)
	}
}

// TestLocationUpdate checks to see if we can update the location string in a pmt correctly
func TestLocationUpdate(t *testing.T) {
	cpy := make([]byte, len(pmtWithMetaTst1))
	copy(cpy, pmtWithMetaTst1)
	cpy = addCrc(cpy)
	err := UpdateLocation(cpy, locationTstStr2)
	cpy = cpy[:len(cpy)-4]
	if err != nil {
		t.Errorf("Update time returned err: %v", err)
	}
	if !bytes.Equal(pmtWithMetaTst2, cpy) {
		t.Errorf(errCmp, "TestLocationUpdate", pmtWithMetaTst2, cpy)
	}
}

func TestTrim(t *testing.T) {
	test := []byte{0xa3, 0x01, 0x03, 0x00, 0xde}
	want := []byte{0xa3, 0x01, 0x03}
	got := trimTo(test, 0x00)
	if !bytes.Equal(got, want) {
		t.Errorf(errCmp, "TestTrim", want, got)
	}
}

// buildPmtTimeLocationBytes is a helper function to help construct the byte slices
// for pmts with time and location, as the location data field is 32 bytes, i.e. quite large
// to type out
func buildPmtWithMeta(tstStr string) []byte {
	dst := make([]byte, len(pmtWithMetaHead)+32+len(pmtWithMetaTail))
	copy(dst, pmtWithMetaHead)
	copy(dst[len(pmtWithMetaHead):], tstStr)
	copy(dst[len(pmtWithMetaHead)+32:], pmtWithMetaTail)
	return dst
}