local testimony = require("testimony")
local litls = require("litls.core")

local hex = litls.hex_encode
local unhex = litls.hex_decode

local testify = testimony.new("== LITLS X.509 / CSR ==")

-- Test certificates generated with openssl (ECDSA P-256, SHA-256)
-- CA: self-signed, CN=Test CA, valid 2026-03-05 to 2036-03-02
-- Leaf: signed by CA, CN=example.com, SANs: example.com, www.example.com

local CA_CERT_DER_HEX = "308201793082011fa00302010202147e5c8ca31ae4a19931c0eb17422f8fbb8e3efe50"
	.. "300a06082a8648ce3d04030230123110300e06035504030c075465737420434130"
	.. "1e170d3236303330353138323430305a170d33363033303231383234303"
	.. "05a30123110300e06035504030c075465737420434130593013060"
	.. "72a8648ce3d020106082a8648ce3d0301070342000442a4c879d7a11ec7bacad310bfee"
	.. "129eef60c90007c4a10cc18283d936f67d78ef4d020fc5f4d6c087268abd48a7ac5415"
	.. "048a41bf2e381f5060df384a71ff9fa3533051301d0603551d0e04160414ad1d1dbe1f"
	.. "d5fd0d859c33a4020e95cea9d31d54301f0603551d23041830168014ad1d1dbe1fd5fd"
	.. "0d859c33a4020e95cea9d31d54300f0603551d130101ff040530030101ff300a06082a"
	.. "8648ce3d040302034800304502204cd5eb336d0b6e75ea185261f36c3c75fcda991a27"
	.. "fe4f7c15bede9a2fa379a3022100bb6784087d6c6ac2c5f6698924e96cd2c0d43b7774"
	.. "28eac21b931d4be3cd9b79"

local LEAF_CERT_DER_HEX = "308201953082013ba0030201020214404907bbaf74bc210426974866d92132e61dffa6"
	.. "300a06082a8648ce3d04030230123110300e06035504030c075465737420434130"
	.. "1e170d3236303330353138323430305a170d3336303330323138323430305a3016"
	.. "3114301206035504030c0b6578616d706c652e636f6d3059301306072a8648ce3d0201"
	.. "06082a8648ce3d030107034200045e360927cf88a126e5142ca95c91294fbc09345eea"
	.. "e29ab609c9313051175272cd887de2efc6ca983073a50dd309e875591e06b0310e350c"
	.. "05315143221d106ca36b306930270603551d110420301e820b6578616d706c652e636f"
	.. "6d820f7777772e6578616d706c652e636f6d301d0603551d0e0416041426ef636dbbbb"
	.. "ef55e61338dec7806e556ea50d10301f0603551d23041830168014ad1d1dbe1fd5fd0d"
	.. "859c33a4020e95cea9d31d54300a06082a8648ce3d0403020348003045022100f4c9b6"
	.. "67d8f4238a990414c8acfc12ae1d61eec815ccec56d2cf8a0c7e5b4b0702203b7a626c"
	.. "7aad4b8eb3d1953a297d663ffa161ede418dd45c31399f7c20bfef79"

local CA_CERT_PEM = [[-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----]]

-- RSA 2048 self-signed cert: CN=RSA Test CA
local RSA_CA_CERT_DER_HEX = "3082030d308201f5a0030201020214183cf45be308b6cb2487345cf5750e0a0525c2c8"
	.. "300d06092a864886f70d01010b050030163114301206035504030c0b52534120546573"
	.. "7420434130"
	.. "1e170d3236303330353138323431365a170d3336303330323138323431365a30163114"
	.. "301206035504030c0b525341205465737420434130820122300d06092a864886f70d01"
	.. "010105000382010f003082010a0282010100cd500b8f36b4fa19f610b019ef35f516fa"
	.. "953bd6ee7d7005069eab9f6bc63f09faf28fcd21e0d8cefb3140a4b30e3eb462929db2"
	.. "1c67e345693348ff8d00c78ab7177e4a986ce11338a1b31d976f97580a9df853a9ca23"
	.. "d0444b32a08c99b98fb1ef87978808d48fed4537446042db18f2a0e43a7631ed6cf066"
	.. "559493b36c8eb6846b983b23c4a4723c8c0120d94d4eca7e5e72c84bbd61146b68f770"
	.. "e6b282cf86f4ce633210ac8a80b3ffa6ec21ca180886f2e40855ca95cac0104a6ca50d"
	.. "d168278bd0929c37e58086be9a5f170045698a48facd3bfc3fe2100dd5424ab5fadcba"
	.. "82df91488204fffa9526a6ece4ed46f63e90c0bc7d8f635d8f9679fb0b0203010001a3"
	.. "533051301d0603551d0e041604144489fed49fb104c9ee72605743ec43248176a058301f"
	.. "0603551d230418301680144489fed49fb104c9ee72605743ec43248176a058300f0603"
	.. "551d130101ff040530030101ff300d06092a864886f70d01010b05000382010100"
	.. "32d66ea6433b5645f6fcd6a53027696b3125d797994e217e91c840ab2b0e54f8e8c620"
	.. "17497ca82f4f3bc756ad092ac39d7a087896b080e1edc72863a4420441c46ed3ee7a78"
	.. "b9a2e1fb9b64758aa1f90dddec93b15022f6557471e81041b87c0d0753c7b8b2bb4fba"
	.. "12e20c99d85bcc7c574ff6dd3dc05857022b5555f9f7698516568fba2c49b14c6531c7"
	.. "ce32582996ed880a200c631b830ec5e699496ce21808c55ece53d2e39860674dc08d525"
	.. "dc5049ec96a009fd8eccb7b57f5fa274de13e917920ee92291973ee182f1a00daceaa73"
	.. "ff421ea9197df1981e615c9843cb362499a10194622c67f596afe709d192a217e6b39a"
	.. "becbb1bfb3a24365a96f"

-- ── PEM decode ──────────────────────────────────────────

testify:that("pem_decode strips PEM headers and base64 decodes", function()
	local der = litls.pem_decode(CA_CERT_PEM)
	testimony.assert_equal(true, der ~= nil)
	local expected = unhex(CA_CERT_DER_HEX)
	testimony.assert_equal(hex(expected), hex(der))
end)

-- ── Certificate parsing ─────────────────────────────────

testify:that("parse ECDSA CA cert: CN, dates", function()
	local der = unhex(CA_CERT_DER_HEX)
	local info = litls.x509_parse(der)
	testimony.assert_equal(true, info ~= nil)
	testimony.assert_equal("Test CA", info.common_name)
	testimony.assert_equal("1772735040", info.not_before)
	testimony.assert_equal("2088095040", info.not_after)
end)

testify:that("parse leaf cert with SANs", function()
	local der = unhex(LEAF_CERT_DER_HEX)
	local info = litls.x509_parse(der)
	testimony.assert_equal(true, info ~= nil)
	testimony.assert_equal("example.com", info.common_name)
	testimony.assert_equal(true, info.sans ~= nil)
	testimony.assert_equal(2, #info.sans)
	testimony.assert_equal("example.com", info.sans[1])
	testimony.assert_equal("www.example.com", info.sans[2])
end)

testify:that("parse RSA cert: CN, dates", function()
	local der = unhex(RSA_CA_CERT_DER_HEX)
	local info = litls.x509_parse(der)
	testimony.assert_equal(true, info ~= nil)
	testimony.assert_equal("RSA Test CA", info.common_name)
	testimony.assert_equal("1772735056", info.not_before)
	testimony.assert_equal("2088095056", info.not_after)
end)

testify:that("parse rejects garbage input", function()
	local info, err = litls.x509_parse("not a certificate")
	testimony.assert_equal(true, info == nil)
end)

-- ── CSR generation ──────────────────────────────────────

testify:that("CSR generation produces valid DER", function()
	local priv, pub = litls.p256_keygen()
	local csr = litls.csr_generate(priv, pub, "test.example.com")
	testimony.assert_equal(true, csr ~= nil)
	-- CSR should start with SEQUENCE tag (0x30)
	testimony.assert_equal(0x30, string.byte(csr, 1))
	-- CSR should be reasonable size
	testimony.assert_equal(true, #csr > 100)
	testimony.assert_equal(true, #csr < 2048)
end)

testify:that("CSR with SANs", function()
	local priv, pub = litls.p256_keygen()
	local sans = { "alt1.example.com", "alt2.example.com" }
	local csr = litls.csr_generate(priv, pub, "main.example.com", sans)
	testimony.assert_equal(true, csr ~= nil)
	-- Verify all domain names appear in the DER output
	testimony.assert_equal(true, csr:find("main.example.com", 1, true) ~= nil)
	testimony.assert_equal(true, csr:find("alt1.example.com", 1, true) ~= nil)
	testimony.assert_equal(true, csr:find("alt2.example.com", 1, true) ~= nil)
end)

-- ── Chain validation ────────────────────────────────────

testify:that("chain validation: ECDSA leaf + CA", function()
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	local ok, err = litls.x509_verify_chain({ leaf_der }, CA_CERT_PEM)
	testimony.assert_equal(true, ok)
end)

testify:that("chain validation rejects unknown anchor", function()
	-- Use the RSA CA PEM as anchor, but leaf was signed by ECDSA CA
	local rsa_ca_pem = "-----BEGIN CERTIFICATE-----\n"
		.. "MIIDDTCCAfWgAwIBAgIUGDz0W+MItsskhzRc9XUOCgUlwsgwDQYJKoZIhvcNAQEL\n"
		.. "BQAwFjEUMBIGA1UEAwwLUlNBIFRlc3QgQ0EwHhcNMjYwMzA1MTgyNDE2WhcNMzYw\n"
		.. "MzAyMTgyNDE2WjAWMRQwEgYDVQQDDAtSU0EgVGVzdCBDQTCCASIwDQYJKoZIhvcN\n"
		.. "AQEBBQADggEPADCCAQoCggEBAM1QC482tPoZ9hCwGe819Rb6lTvW7n1wBQaeq59r\n"
		.. "xj8J+vKPzSHg2M77MUCksw4+tGKSnbIcZ+NFaTNI/40Ax4q3F35KmGzhEzihsx2X\n"
		.. "b5dYCp34U6nKI9BESzKgjJm5j7Hvh5eICNSP7UU3RGBC2xjyoOQ6djHtbPBmVZST\n"
		.. "s2yOtoRrmDsjxKRyPIwBINlNTsp+XnLIS71hFGto93DmsoLPhvTOYzIQrIqAs/+m\n"
		.. "7CHKGAiG8uQIVcqVysAQSmylDdFoJ4vQkpw35YCGvppfFwBFaYpI+s07/D/iEA3V\n"
		.. "Qkq1+ty6gt+RSIIE//qVJqbs5O1G9j6QwLx9j2Ndj5Z5+wsCAwEAAaNTMFEwHQYD\n"
		.. "VR0OBBYEFESJ/tSfsQTJ7nJgV0PsQySBdqBYMB8GA1UdIwQYMBaAFESJ/tSfsQTJ\n"
		.. "7nJgV0PsQySBdqBYMA8GA1UdEwEB/wQFMAMBAf8wDQYJKoZIhvcNAQELBQADggEB\n"
		.. "ADLWbqZDO1ZF9vzWpTAnaWsxJdeXmU4hfpHIQKsrDlT46MYgF0l8qC9PO8dWrQkq\n"
		.. "w516CHiWsIDh7ccoY6RCBEHEbtPueni5ouH7m2R1iqH5Dd3sk7FQIvZVdHHoEEG4\n"
		.. "fA0HU8e4srtPuhLiDJnYW8x8V0/23T3AWFcCK1VV+fdphRZWj7osSbFMZTHHzjJY\n"
		.. "KZbtiAogDGMbgw7F5plJbOIYCMVezlPS45hgZ03AjVJdxQSeyWoAn9jsy3tX9fon\n"
		.. "TeE+kXkg7pIpGXPuGC8aANrOqnP/Qh6pGX3xmB5hXJhDyzYkmaEBlGIsZ/WWr+cJ\n"
		.. "0ZKiF+azmr7Lsb+zokNlqW8=\n"
		.. "-----END CERTIFICATE-----"
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	local ok, err = litls.x509_verify_chain({ leaf_der }, rsa_ca_pem)
	testimony.assert_equal(true, ok == nil)
	testimony.assert_equal(true, err ~= nil)
end)

testify:that("chain validation: RSA self-signed cert validates against itself", function()
	local rsa_der = unhex(RSA_CA_CERT_DER_HEX)
	local rsa_pem = "-----BEGIN CERTIFICATE-----\n"
		.. "MIIDDTCCAfWgAwIBAgIUGDz0W+MItsskhzRc9XUOCgUlwsgwDQYJKoZIhvcNAQEL\n"
		.. "BQAwFjEUMBIGA1UEAwwLUlNBIFRlc3QgQ0EwHhcNMjYwMzA1MTgyNDE2WhcNMzYw\n"
		.. "MzAyMTgyNDE2WjAWMRQwEgYDVQQDDAtSU0EgVGVzdCBDQTCCASIwDQYJKoZIhvcN\n"
		.. "AQEBBQADggEPADCCAQoCggEBAM1QC482tPoZ9hCwGe819Rb6lTvW7n1wBQaeq59r\n"
		.. "xj8J+vKPzSHg2M77MUCksw4+tGKSnbIcZ+NFaTNI/40Ax4q3F35KmGzhEzihsx2X\n"
		.. "b5dYCp34U6nKI9BESzKgjJm5j7Hvh5eICNSP7UU3RGBC2xjyoOQ6djHtbPBmVZST\n"
		.. "s2yOtoRrmDsjxKRyPIwBINlNTsp+XnLIS71hFGto93DmsoLPhvTOYzIQrIqAs/+m\n"
		.. "7CHKGAiG8uQIVcqVysAQSmylDdFoJ4vQkpw35YCGvppfFwBFaYpI+s07/D/iEA3V\n"
		.. "Qkq1+ty6gt+RSIIE//qVJqbs5O1G9j6QwLx9j2Ndj5Z5+wsCAwEAAaNTMFEwHQYD\n"
		.. "VR0OBBYEFESJ/tSfsQTJ7nJgV0PsQySBdqBYMB8GA1UdIwQYMBaAFESJ/tSfsQTJ\n"
		.. "7nJgV0PsQySBdqBYMA8GA1UdEwEB/wQFMAMBAf8wDQYJKoZIhvcNAQELBQADggEB\n"
		.. "ADLWbqZDO1ZF9vzWpTAnaWsxJdeXmU4hfpHIQKsrDlT46MYgF0l8qC9PO8dWrQkq\n"
		.. "w516CHiWsIDh7ccoY6RCBEHEbtPueni5ouH7m2R1iqH5Dd3sk7FQIvZVdHHoEEG4\n"
		.. "fA0HU8e4srtPuhLiDJnYW8x8V0/23T3AWFcCK1VV+fdphRZWj7osSbFMZTHHzjJY\n"
		.. "KZbtiAogDGMbgw7F5plJbOIYCMVezlPS45hgZ03AjVJdxQSeyWoAn9jsy3tX9fon\n"
		.. "TeE+kXkg7pIpGXPuGC8aANrOqnP/Qh6pGX3xmB5hXJhDyzYkmaEBlGIsZ/WWr+cJ\n"
		.. "0ZKiF+azmr7Lsb+zokNlqW8=\n"
		.. "-----END CERTIFICATE-----"
	local ok, err = litls.x509_verify_chain({ rsa_der }, rsa_pem)
	testimony.assert_equal(true, ok)
end)

testify:that("chain validation rejects corrupted signature", function()
	-- Corrupt one byte of the leaf cert
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	-- Flip a byte near the end (in the signature area)
	local corrupted = leaf_der:sub(1, #leaf_der - 5) .. string.char(0xFF) .. leaf_der:sub(#leaf_der - 3)
	local ok, err = litls.x509_verify_chain({ corrupted }, CA_CERT_PEM)
	testimony.assert_equal(true, ok == nil)
end)

-- ── Extension parsing (BasicConstraints / KeyUsage / EKU) ──────

testify:that("parse CA cert exposes BasicConstraints CA=true", function()
	local der = unhex(CA_CERT_DER_HEX)
	local info = litls.x509_parse(der)
	testimony.assert_equal(true, info ~= nil)
	-- The test CA was generated with "CA:TRUE" basicConstraints.
	testimony.assert_equal(true, info.is_ca == true)
end)

testify:that("parse leaf cert without BasicConstraints omits is_ca", function()
	local der = unhex(LEAF_CERT_DER_HEX)
	local info = litls.x509_parse(der)
	testimony.assert_equal(true, info ~= nil)
	-- Leaf has no BasicConstraints extension, so the field should be absent.
	testimony.assert_equal(true, info.is_ca == nil)
end)

-- ── Hostname verification (RFC 6125) ──────────────────────────

testify:that("hostname match: SAN dNSName exact", function()
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	-- LEAF SANs: "example.com", "www.example.com"
	testimony.assert_equal(true, litls.x509_verify_hostname(leaf_der, "example.com") == true)
	testimony.assert_equal(true, litls.x509_verify_hostname(leaf_der, "www.example.com") == true)
end)

testify:that("hostname match: case-insensitive", function()
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	testimony.assert_equal(true, litls.x509_verify_hostname(leaf_der, "EXAMPLE.com") == true)
end)

testify:that("hostname match: trailing dot FQDN stripped", function()
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	testimony.assert_equal(true, litls.x509_verify_hostname(leaf_der, "example.com.") == true)
end)

testify:that("hostname mismatch: different domain", function()
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	local ok, err = litls.x509_verify_hostname(leaf_der, "evil.com")
	testimony.assert_equal(true, ok == nil)
	testimony.assert_equal(true, err ~= nil)
end)

testify:that("hostname mismatch: subdomain of SAN (no wildcard)", function()
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	-- SAN is "example.com" (not "*.example.com") so "a.example.com" must fail.
	local ok = litls.x509_verify_hostname(leaf_der, "a.example.com")
	testimony.assert_equal(true, ok == nil)
end)

testify:that("hostname mismatch: empty input fails closed", function()
	local leaf_der = unhex(LEAF_CERT_DER_HEX)
	local ok = litls.x509_verify_hostname(leaf_der, "")
	testimony.assert_equal(true, ok == nil)
end)

testify:conclude()