// Copyright 2024 Martin Riedl
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// 	http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package gomp4

import (
	"encoding/binary"
	"time"
)

// MediaHeaderBox media header box struct
//
// 8.4.2 Media Header Box
//
// Box Type: ‘mdhd’
// Container: Media Box (‘mdia’)
// Mandatory: Yes
// Quantity: Exactly one
//
// The media header declares overall information that is media‐independent, and relevant to
// characteristics of the media in a track.
type MediaHeaderBox struct {
	*FullBox
	// is an integer that declares the creation time of the media in this track (in
	// seconds since midnight, Jan. 1, 1904, in UTC time).
	CreationTimeV0 time.Time
	// is an integer that declares the creation time of the media in this track (in
	// seconds since midnight, Jan. 1, 1904, in UTC time).
	CreationTimeV1 time.Time
	// is an integer that declares the most recent time the media in this track was
	// modified (in seconds since midnight, Jan. 1, 1904, in UTC time).
	ModificationTimeV0 time.Time
	// is an integer that declares the most recent time the media in this track was
	// modified (in seconds since midnight, Jan. 1, 1904, in UTC time).
	ModificationTimeV1 time.Time
	// is an integer that specifies the time‐scale for this media; this is the number of time
	// units that pass in one second. For example, a time coordinate system that measures time in
	// sixtieths of a second has a time scale of 60.
	Timescale uint32
	// is an integer that declares the duration of this media (in the scale of the timescale). If the
	// duration cannot be determined then duration is set to all 1s.
	DurationV0 uint32
	// is an integer that declares the duration of this media (in the scale of the timescale). If the
	// duration cannot be determined then duration is set to all 1s.
	DurationV1 uint64

	// TODO: parse language language
}

// ParseMediaHeaderBox creates a new Media Header Box struct
func ParseMediaHeaderBox(filePosition uint64, headerSize uint32, content []byte) *MediaHeaderBox {
	box := &MediaHeaderBox{
		FullBox: newFullBox(&Box{filePosition, headerSize}, content[0:4]),
	}

	position := 4
	if box.Version == 1 {
		box.CreationTimeV1 = since1904ToTime(int64(binary.BigEndian.Uint64(content[position : position+8])))
		box.ModificationTimeV1 = since1904ToTime(int64(binary.BigEndian.Uint64(content[position+8 : position+16])))
		box.Timescale = binary.BigEndian.Uint32(content[position+16 : position+20])
		box.DurationV1 = binary.BigEndian.Uint64(content[position+20 : position+28])
		position += 28
	} else { // version == 0
		box.CreationTimeV0 = since1904ToTime(int64(binary.BigEndian.Uint32(content[position : position+4])))
		box.ModificationTimeV0 = since1904ToTime(int64(binary.BigEndian.Uint32(content[position+4 : position+8])))
		box.Timescale = binary.BigEndian.Uint32(content[position+8 : position+12])
		box.DurationV0 = binary.BigEndian.Uint32(content[position+12 : position+16])
		position += 16
	}

	// TODO: parse language language

	return box
}