// Package windsurf is a minimal Go client for the Windsurf LanguageServerService (local gRPC)
// and upstream Connect-RPC JSON endpoints.
//
// Portions of this file derive from https://github.com/seven7763/windsurf-tools (MIT, 2025 shaoyu521).
// See ./LICENSE for full attribution.
package windsurf

import (
	"encoding/hex"
)

// ── Constants ──────────────────────────────────────────────────────────────

const (
	DefaultBaseURL = "https://server.self-serve.windsurf.com"

	AppName          = "windsurf"
	AppVersion       = "1.48.2"
	ExtensionVersion = "1.9600.41"
	IDEVersion       = ExtensionVersion
	RuntimeOS        = "linux"
	HardwareArch     = "x86_64"
	ClientVersion    = "2.0.63"
	UserAgent        = "connect-go/1.18.1 (go1.26.1)"
)

// ── Protobuf wire encoding ─────────────────────────────────────────────────

func writeVarint(value uint64) []byte {
	var parts []byte
	for value > 0x7F {
		parts = append(parts, byte(value&0x7F)|0x80)
		value >>= 7
	}
	parts = append(parts, byte(value))
	return parts
}

func encodeBytesField(fieldNum uint64, data []byte) []byte {
	tag := writeVarint((fieldNum << 3) | 2)
	length := writeVarint(uint64(len(data)))
	out := make([]byte, 0, len(tag)+len(length)+len(data))
	out = append(out, tag...)
	out = append(out, length...)
	out = append(out, data...)
	return out
}

func encodeStringField(fieldNum uint64, s string) []byte {
	return encodeBytesField(fieldNum, []byte(s))
}

func encodeVarintField(fieldNum uint64, value uint64) []byte {
	tag := writeVarint((fieldNum << 3) | 0)
	val := writeVarint(value)
	out := make([]byte, 0, len(tag)+len(val))
	out = append(out, tag...)
	out = append(out, val...)
	return out
}

// ReadVarint reads a varint from data starting at pos.
func ReadVarint(data []byte, pos int) (val uint64, newPos int, ok bool) {
	var shift uint
	for pos < len(data) {
		b := data[pos]
		pos++
		val |= uint64(b&0x7F) << shift
		shift += 7
		if (b & 0x80) == 0 {
			return val, pos, true
		}
		if shift >= 64 {
			return 0, pos, false
		}
	}
	return 0, pos, false
}

// ── UUID ───────────────────────────────────────────────────────────────────

func generateUUID() string {
	var buf [16]byte
	_, _ = readRandom(buf[:])
	buf[6] = (buf[6] & 0x0f) | 0x40
	buf[8] = (buf[8] & 0x3f) | 0x80
	return hex.EncodeToString(buf[0:4]) + "-" +
		hex.EncodeToString(buf[4:6]) + "-" +
		hex.EncodeToString(buf[6:8]) + "-" +
		hex.EncodeToString(buf[8:10]) + "-" +
		hex.EncodeToString(buf[10:16])
}