package main

import (
	"git.smesh.lol/smesh/web/common/helpers"
	"git.smesh.lol/smesh/web/common/jsbridge/ext"
	"git.smesh.lol/smesh/web/common/jsbridge/schnorr"
	"git.smesh.lol/smesh/web/common/jsbridge/subtle"
)

// Management API: vault lifecycle, identity CRUD, export/import.

func mgmtGetVaultStatus() (s string) {
	if !vaultExists {
		return jsonResult(string(append([]byte(nil), '"', 'n', 'o', 'n', 'e', '"')))
	}
	if vaultOpen {
		return jsonResult(string(append([]byte(nil), '"', 'u', 'n', 'l', 'o', 'c', 'k', 'e', 'd', '"')))
	}
	return jsonResult(string(append([]byte(nil), '"', 'l', 'o', 'c', 'k', 'e', 'd', '"')))
}

func mgmtUnlockVault(paramsJSON string) (s string) {
	kPassword := string(append([]byte(nil), 'p', 'a', 's', 's', 'w', 'o', 'r', 'd'))
	pw := helpers.JsonGetString(paramsJSON, kPassword)
	if pw == "" {
		return jsonErr(string(append([]byte(nil), 'm', 'i', 's', 's', 'i', 'n', 'g', ' ', 'p', 'a', 's', 's', 'w', 'o', 'r', 'd')))
	}
	if unlockVault(pw) {
		return jsonTrue()
	}
	if lastUnlockErr != "" {
		return jsonErr(lastUnlockErr)
	}
	return jsonFalse()
}

func mgmtCreateVault(paramsJSON string) (s string) {
	kPassword := string(append([]byte(nil), 'p', 'a', 's', 's', 'w', 'o', 'r', 'd'))
	pw := helpers.JsonGetString(paramsJSON, kPassword)
	if pw == "" {
		return jsonErr(string(append([]byte(nil), 'm', 'i', 's', 's', 'i', 'n', 'g', ' ', 'p', 'a', 's', 's', 'w', 'o', 'r', 'd')))
	}
	if createVault(pw) {
		return jsonTrue()
	}
	return jsonFalse()
}

func mgmtLockVault() (s string) {
	lockVault()
	return jsonTrue()
}

func mgmtListIdentities() (s string) {
	if !vaultOpen {
		return jsonErr(string(append([]byte(nil), 'v', 'a', 'u', 'l', 't', ' ', 'l', 'o', 'c', 'k', 'e', 'd')))
	}
	b := append([]byte(nil), '{', '"', 'r', 'e', 's', 'u', 'l', 't', '"', ':', '[')
	for i, id := range identities {
		if i > 0 {
			b = append(b, ',')
		}
		b = append(b, '{', '"', 'p', 'u', 'b', 'k', 'e', 'y', '"', ':')
		b = b | helpers.JsonString(id.Pubkey)
		b = append(b, ',', '"', 'n', 'a', 'm', 'e', '"', ':')
		b = b | helpers.JsonString(id.Name)
		b = append(b, '}')
	}
	return string(append(b, ']', '}'))
}

func mgmtSwitchIdentity(paramsJSON string) (s string) {
	if !vaultOpen {
		return jsonErr(string(append([]byte(nil), 'v', 'a', 'u', 'l', 't', ' ', 'l', 'o', 'c', 'k', 'e', 'd')))
	}
	kPubkey := string(append([]byte(nil), 'p', 'u', 'b', 'k', 'e', 'y'))
	pk := helpers.JsonGetString(paramsJSON, kPubkey)
	for i, id := range identities {
		if id.Pubkey == pk {
			activeIdx = i
			cacheSession()
			return jsonTrue()
		}
	}
	return jsonFalse()
}

func mgmtAddIdentity(paramsJSON string) (s string) {
	if !vaultOpen {
		return jsonErr(string(append([]byte(nil), 'v', 'a', 'u', 'l', 't', ' ', 'l', 'o', 'c', 'k', 'e', 'd')))
	}
	kNsec := string(append([]byte(nil), 'n', 's', 'e', 'c'))
	kSeckey := string(append([]byte(nil), 's', 'e', 'c', 'k', 'e', 'y'))
	kName := string(append([]byte(nil), 'n', 'a', 'm', 'e'))
	nsec := helpers.JsonGetString(paramsJSON, kNsec)
	sk := helpers.JsonGetString(paramsJSON, kSeckey)
	name := helpers.JsonGetString(paramsJSON, kName)
	var skBytes []byte
	if nsec != "" {
		// Page-side API passes bech32 nsec.
		raw, ok := decodeNsec(nsec)
		if !ok {
			return jsonErr(string(append([]byte(nil), 'i', 'n', 'v', 'a', 'l', 'i', 'd', ' ', 'n', 's', 'e', 'c')))
		}
		skBytes = raw[:]
		sk = helpers.HexEncode(skBytes)
	} else if sk != "" {
		// Backward-compat: hex seckey.
		skBytes = helpers.HexDecode(sk)
		if skBytes == nil {
			return jsonErr(string(append([]byte(nil), 'i', 'n', 'v', 'a', 'l', 'i', 'd', ' ', 's', 'e', 'c', 'k', 'e', 'y')))
		}
	} else {
		// Neither nsec nor seckey provided: generate a fresh random identity.
		var raw [32]byte
		subtle.RandomBytes(raw[:])
		skBytes = raw[:]
		sk = helpers.HexEncode(skBytes)
	}
	pkBytes, ok := schnorr.PubKeyFromSecKey(skBytes)
	if !ok {
		return jsonErr(string(append([]byte(nil), 'k', 'e', 'y', ' ', 'd', 'e', 'r', 'i', 'v', 'a', 't', 'i', 'o', 'n', ' ', 'f', 'a', 'i', 'l', 'e', 'd')))
	}
	pk := helpers.HexEncode(pkBytes)
	for _, id := range identities {
		if id.Pubkey == pk {
			return jsonErr(string(append([]byte(nil), 'i', 'd', 'e', 'n', 't', 'i', 't', 'y', ' ', 'e', 'x', 'i', 's', 't', 's')))
		}
	}
	identities = append(identities, identity{Pubkey: pk, Seckey: sk, Name: name})
	if activeIdx < 0 {
		activeIdx = len(identities) - 1
	}
	saveVault()
	return jsonResult(helpers.JsonString(pk))
}

// decodeNsec decodes a bech32-encoded nsec1... string into 32 raw bytes.
// Returns ([32]byte{}, false) on invalid format/length/charset.
func decodeNsec(nsec string) ([32]byte, bool) {
	var zero [32]byte
	prefix := string(append([]byte(nil), 'n', 's', 'e', 'c', '1'))
	if len(nsec) < 5 || nsec[:5] != prefix {
		return zero, false
	}
	sep := -1
	for i := len(nsec) - 1; i >= 0; i-- {
		if nsec[i] == '1' {
			sep = i
			break
		}
	}
	if sep < 0 || len(nsec)-sep-1 <= 6 {
		return zero, false
	}
	data := nsec[sep+1 : len(nsec)-6]
	out := []byte{:32}[:0]
	acc := uint32(0)
	bits := uint32(0)
	for i := 0; i < len(data); i++ {
		v, ok := bech32CharVal(data[i])
		if !ok {
			return zero, false
		}
		acc = (acc << 5) | uint32(v)
		bits += 5
		for bits >= 8 {
			bits -= 8
			out = append(out, byte(acc>>bits))
		}
	}
	if len(out) != 32 {
		return zero, false
	}
	var result [32]byte
	for i := 0; i < 32; i++ {
		result[i] = out[i]
	}
	return result, true
}

func mgmtRemoveIdentity(paramsJSON string) (s string) {
	if !vaultOpen {
		return jsonErr(string(append([]byte(nil), 'v', 'a', 'u', 'l', 't', ' ', 'l', 'o', 'c', 'k', 'e', 'd')))
	}
	kPubkey := string(append([]byte(nil), 'p', 'u', 'b', 'k', 'e', 'y'))
	pk := helpers.JsonGetString(paramsJSON, kPubkey)
	for i, id := range identities {
		if id.Pubkey == pk {
			identities = identities[:i] | identities[i+1:]
			if activeIdx >= len(identities) {
				activeIdx = len(identities) - 1
			}
			saveVault()
			return jsonTrue()
		}
	}
	return jsonFalse()
}

func mgmtNsecLogin(paramsJSON string) (s string) {
	kNsec := string(append([]byte(nil), 'n', 's', 'e', 'c'))
	nsec := helpers.JsonGetString(paramsJSON, kNsec)
	if nsec == "" {
		return jsonErr(string(append([]byte(nil), 'm', 'i', 's', 's', 'i', 'n', 'g', ' ', 'n', 's', 'e', 'c')))
	}
	raw, ok := decodeNsec(nsec)
	if !ok {
		return jsonErr(string(append([]byte(nil), 'i', 'n', 'v', 'a', 'l', 'i', 'd', ' ', 'n', 's', 'e', 'c')))
	}
	skBytes := raw[:]
	sk := helpers.HexEncode(skBytes)
	pkBytes, ok := schnorr.PubKeyFromSecKey(skBytes)
	if !ok {
		return jsonErr(string(append([]byte(nil), 'k', 'e', 'y', ' ', 'd', 'e', 'r', 'i', 'v', 'a', 't', 'i', 'o', 'n', ' ', 'f', 'a', 'i', 'l', 'e', 'd')))
	}
	pk := helpers.HexEncode(pkBytes)
	identities = []identity{{Pubkey: pk, Seckey: sk, Name: ""}}
	activeIdx = 0
	vaultOpen = true
	vaultExists = true
	vaultVersion = 0
	_ = ext.StorageSet
	return jsonTrue()
}

// bech32CharVal returns the 5-bit value for a bech32 character.
// Charset: "qpzry9x8gf2tvdw0s3jn54khce6mua7l"
func bech32CharVal(c byte) (byte, bool) {
	switch c {
	case 'q':
		return 0, true
	case 'p':
		return 1, true
	case 'z':
		return 2, true
	case 'r':
		return 3, true
	case 'y':
		return 4, true
	case '9':
		return 5, true
	case 'x':
		return 6, true
	case '8':
		return 7, true
	case 'g':
		return 8, true
	case 'f':
		return 9, true
	case '2':
		return 10, true
	case 't':
		return 11, true
	case 'v':
		return 12, true
	case 'd':
		return 13, true
	case 'w':
		return 14, true
	case '0':
		return 15, true
	case 's':
		return 16, true
	case '3':
		return 17, true
	case 'j':
		return 18, true
	case 'n':
		return 19, true
	case '5':
		return 20, true
	case '4':
		return 21, true
	case 'k':
		return 22, true
	case 'h':
		return 23, true
	case 'c':
		return 24, true
	case 'e':
		return 25, true
	case '6':
		return 26, true
	case 'm':
		return 27, true
	case 'u':
		return 28, true
	case 'a':
		return 29, true
	case '7':
		return 30, true
	case 'l':
		return 31, true
	}
	return 0, false
}

func mgmtExportVault(paramsJSON string) (s string) {
	if !vaultOpen {
		return jsonErr(string(append([]byte(nil), 'v', 'a', 'u', 'l', 't', ' ', 'l', 'o', 'c', 'k', 'e', 'd')))
	}
	kPassword := string(append([]byte(nil), 'p', 'a', 's', 's', 'w', 'o', 'r', 'd'))
	pw := helpers.JsonGetString(paramsJSON, kPassword)
	if pw == "" {
		return jsonErr(string(append([]byte(nil), 'm', 'i', 's', 's', 'i', 'n', 'g', ' ', 'p', 'a', 's', 's', 'w', 'o', 'r', 'd')))
	}
	salt := []byte{:32}
	subtle.RandomBytes(salt)
	hash := passwordHash(pw)
	if hash == "" {
		return jsonErr(string(append([]byte(nil), 'h', 'a', 's', 'h', ' ', 'f', 'a', 'i', 'l', 'e', 'd')))
	}
	key := subtle.Argon2idDeriveKey(pw, salt, argon2T, argon2MNew, argon2P, argon2DKLen)
	if len(key) == 0 {
		return jsonErr(string(append([]byte(nil), 'k', 'e', 'y', ' ', 'f', 'a', 'i', 'l', 'e', 'd')))
	}
	b := []byte{:512}[:0]
	b = append(b, '{', '"', 'v', 'e', 'r', 's', 'i', 'o', 'n', '"', ':', '3')
	b = append(b, ',', '"', 'a', 'r', 'g', 'o', 'n', '2', 'M', '"', ':')
	b = b | helpers.Itoa(int64(argon2MNew))
	b = append(b, ',', '"', 's', 'a', 'l', 't', '"', ':')
	b = b | helpers.JsonString(helpers.Base64Encode(salt))
	b = append(b, ',', '"', 'v', 'a', 'u', 'l', 't', 'H', 'a', 's', 'h', '"', ':')
	b = b | helpers.JsonString(hash)
	b = append(b, ',', '"', 'i', 'd', 'e', 'n', 't', 'i', 't', 'i', 'e', 's', '"', ':', '[')
	for i, id := range identities {
		if i > 0 {
			b = append(b, ',')
		}
		encSk, ok := encryptFieldWith(id.Seckey, key)
		if !ok {
			encSk = ""
		}
		b = append(b, '{', '"', 'p', 'u', 'b', 'k', 'e', 'y', '"', ':')
		b = b | helpers.JsonString(id.Pubkey)
		b = append(b, ',', '"', 's', 'e', 'c', 'k', 'e', 'y', '"', ':')
		b = b | helpers.JsonString(encSk)
		b = append(b, ',', '"', 'n', 'a', 'm', 'e', '"', ':')
		b = b | helpers.JsonString(id.Name)
		b = append(b, '}')
	}
	b = append(b, ']', '}')
	return jsonResult(string(b))
}

func mgmtImportVault(paramsJSON string) (s string) {
	kData := string(append([]byte(nil), 'd', 'a', 't', 'a'))
	data := helpers.JsonGetString(paramsJSON, kData)
	if data == "" {
		return jsonErr(string(append([]byte(nil), 'm', 'i', 's', 's', 'i', 'n', 'g', ' ', 'd', 'a', 't', 'a')))
	}
	kVersion := string(append([]byte(nil), 'v', 'e', 'r', 's', 'i', 'o', 'n'))
	kVaultHash := string(append([]byte(nil), 'v', 'a', 'u', 'l', 't', 'H', 'a', 's', 'h'))
	ver := helpers.JsonGetValue(data, kVersion)
	vh := helpers.JsonGetString(data, kVaultHash)
	if ver == "" || vh == "" {
		return jsonErr(string(append([]byte(nil), 'i', 'n', 'v', 'a', 'l', 'i', 'd', ' ', 'v', 'a', 'u', 'l', 't', ' ', 'f', 'o', 'r', 'm', 'a', 't')))
	}
	vaultRawCache = data
	vaultExists = true
	vaultOpen = false
	kVault := string(append([]byte(nil), 's', 'm', 'e', 's', 'h', '-', 'v', 'a', 'u', 'l', 't'))
	ext.StorageSet(kVault, data)
	return jsonTrue()
}

func mgmtResetExtension() (s string) {
	ext.StorageRemove(vaultStorageKey)
	ext.StorageRemove(string(append([]byte(nil), 's', 'm', 'e', 's', 'h', '-', 'p', 'e', 'r', 'm', 'i', 's', 's', 'i', 'o', 'n', 's')))
	lockVault()
	vaultExists = false
	vaultRawCache = ""
	return jsonTrue()
}