// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

package utils

import (
	"net/http"
	"net/http/httptest"
	"testing"

	"github.com/stretchr/testify/assert"

	"github.com/mattermost/mattermost/server/public/model"
)

func TestStringArrayIntersection(t *testing.T) {
	a := []string{
		"abc",
		"def",
		"ghi",
	}
	b := []string{
		"jkl",
	}
	c := []string{
		"def",
	}

	assert.Empty(t, StringArrayIntersection(a, b))
	assert.Len(t, StringArrayIntersection(a, c), 1)
}

func TestRemoveDuplicatesFromStringArray(t *testing.T) {
	a := []string{
		"a",
		"b",
		"a",
		"a",
		"b",
		"c",
		"a",
	}

	assert.Len(t, RemoveDuplicatesFromStringArray(a), 3)
}

func TestStringSliceDiff(t *testing.T) {
	a := []string{"one", "two", "three", "four", "five", "six"}
	b := []string{"two", "seven", "four", "six"}
	expected := []string{"one", "three", "five"}

	assert.Equal(t, expected, StringSliceDiff(a, b))
}

func TestGetIPAddress(t *testing.T) {
	t.Run("Single IP in the X-Forwarded-For", func(t *testing.T) {
		httpRequest1 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"10.0.0.1"},
				"X-Real-Ip":       []string{"10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.0.0.1", GetIPAddress(&httpRequest1, []string{"X-Forwarded-For"}))
	})

	t.Run("Multiple IPs in the X-Forwarded-For", func(t *testing.T) {
		httpRequest2 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"10.0.0.1,  10.0.0.2, 10.0.0.3"},
				"X-Real-Ip":       []string{"10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.0.0.1", GetIPAddress(&httpRequest2, []string{"X-Forwarded-For"}))
	})

	t.Run("Empty X-Forwarded-For", func(t *testing.T) {
		httpRequest3 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{""},
				"X-Real-Ip":       []string{"10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.1.0.1", GetIPAddress(&httpRequest3, []string{"X-Forwarded-For", "X-Real-Ip"}))
	})

	t.Run("Without an X-Forwarded-For", func(t *testing.T) {
		httpRequest4 := http.Request{
			Header: http.Header{
				"X-Real-Ip": []string{"10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.1.0.1", GetIPAddress(&httpRequest4, []string{"X-Forwarded-For", "X-Real-Ip"}))
	})

	t.Run("Without any headers", func(t *testing.T) {
		httpRequest5 := http.Request{
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.2.0.1", GetIPAddress(&httpRequest5, []string{"X-Forwarded-For", "X-Real-Ip"}))
	})

	t.Run("Two headers, but both untrusted", func(t *testing.T) {
		httpRequest6 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"10.3.0.1"},
				"X-Real-Ip":       []string{"10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.2.0.1", GetIPAddress(&httpRequest6, nil))
	})

	t.Run("Two headers, but only X-Real-Ip trusted", func(t *testing.T) {
		httpRequest7 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"10.3.0.1"},
				"X-Real-Ip":       []string{"10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.1.0.1", GetIPAddress(&httpRequest7, []string{"X-Real-Ip"}))
	})

	t.Run("X-Forwarded-For, comma separated, untrusted", func(t *testing.T) {
		httpRequest8 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"10.3.0.1, 10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.2.0.1", GetIPAddress(&httpRequest8, nil))
	})

	t.Run("X-Forwarded-For, comma separated, untrusted", func(t *testing.T) {
		httpRequest9 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"10.3.0.1, 10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.3.0.1", GetIPAddress(&httpRequest9, []string{"X-Forwarded-For"}))
	})

	t.Run("Two headers, both allowed, first one in trusted used", func(t *testing.T) {
		httpRequest10 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"10.3.0.1"},
				"X-Real-Ip":       []string{"10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.1.0.1", GetIPAddress(&httpRequest10, []string{"X-Real-Ip", "X-Forwarded-For"}))
	})

	t.Run("Multiple IPs in the X-Forwarded-For with no spaces", func(t *testing.T) {
		httpRequest11 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"10.0.0.1,10.0.0.2,10.0.0.3"},
				"X-Real-Ip":       []string{"10.1.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.0.0.1", GetIPAddress(&httpRequest11, []string{"X-Forwarded-For"}))
	})

	t.Run("Make sure that the parsed value from headers only accept IP Addresses", func(t *testing.T) {
		httpRequest12 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"127.0.0.1"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "127.0.0.1", GetIPAddress(&httpRequest12, []string{"X-Forwarded-For"}))

		httpRequest13 := http.Request{
			Header: http.Header{
				"X-Forwarded-For": []string{"localhost"},
			},
			RemoteAddr: "10.2.0.1:12345",
		}

		assert.Equal(t, "10.2.0.1", GetIPAddress(&httpRequest13, []string{"X-Forwarded-For"}))
	})
}

func TestRemoveStringFromSlice(t *testing.T) {
	a := []string{"one", "two", "three", "four", "five", "six"}
	expected := []string{"one", "two", "three", "five", "six"}

	assert.Equal(t, RemoveStringFromSlice("four", a), expected)
}

func TestAppendQueryParamsToURL(t *testing.T) {
	url := "mattermost://callback"
	redirectURL := AppendQueryParamsToURL(url, map[string]string{
		"key1": "value1",
		"key2": "value2",
	})
	expected := url + "?key1=value1&key2=value2"
	assert.Equal(t, redirectURL, expected)
}

func TestRoundOffToZeroes(t *testing.T) {
	testCases := []struct {
		desc     string
		n        float64
		expected int64
	}{
		{
			desc:     "returns 0 when n is 0",
			n:        0,
			expected: 0,
		},
		{
			desc:     "returns 0 when n is 9",
			n:        9,
			expected: 0,
		},
		{
			desc:     "returns 10 when n is 10",
			n:        10,
			expected: 10,
		},
		{
			desc:     "returns 90 when n is 99",
			n:        99,
			expected: 90,
		},
		{
			desc:     "returns 100 when n is 100",
			n:        100,
			expected: 100,
		},
		{
			desc:     "returns 100 when n is 101",
			n:        101,
			expected: 100,
		},
		{
			desc:     "returns 4000 when n is 4321",
			n:        4321,
			expected: 4000,
		},
		{
			desc:     "returns 0 when n is -9",
			n:        -9,
			expected: 0,
		},
		{
			desc:     "returns -4000 when n is -4321",
			n:        -4321,
			expected: -4000,
		},
		{
			desc:     "returns 4000 when n is 4321.235",
			n:        4321.235,
			expected: 4000,
		},
	}
	for _, tc := range testCases {
		t.Run(tc.desc, func(t *testing.T) {
			res := RoundOffToZeroes(tc.n)
			assert.Equal(t, tc.expected, res)
		})
	}
}

func TestIsMobileRequest(t *testing.T) {
	testCases := []struct {
		userAgent string
		expected  bool
	}{
		// Test cases with mobile devices
		{"Mozilla/5.0 (iPhone; CPU iPhone OS 15_0 like Mac OS X)", true},
		{"Mozilla/5.0 (Android 12; Mobile)", true},
		{"Mozilla/5.0 (Linux; Android 12; Pixel 6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.9999.99 Mobile Safari/537.36", true},

		// Test cases with NO mobile devices
		{"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36", false},
		{"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/96.0.4664.45 Safari/537.36", false},
	}

	for _, tc := range testCases {
		req := httptest.NewRequest(http.MethodGet, "/", nil)
		req.Header.Set("User-Agent", tc.userAgent)

		result := IsMobileRequest(req)
		if result != tc.expected {
			t.Errorf("User-Agent: %s, expected: %v, got: %v", tc.userAgent, tc.expected, result)
		}
	}
}

func TestRoundOffToZeroesResolution(t *testing.T) {
	messageGranularity := 3
	storageGranularity := 8
	testCases := []struct {
		desc          string
		n             float64
		minResolution int
		expected      int64
	}{
		{
			desc:     "returns 0 when n is 0",
			n:        0,
			expected: 0,
		},
		{
			desc:          "resolution of 0 does not round",
			n:             12345,
			expected:      12345,
			minResolution: 0,
		},
		{
			desc:          "resolution of 1 truncates to 10s: 9 -> 0",
			n:             9,
			expected:      0,
			minResolution: 1,
		},
		{
			desc:          "resolution of 1 truncates to 10s: 10 -> 10",
			n:             10,
			expected:      10,
			minResolution: 1,
		},
		{
			desc:          "resolution of 1 truncates to 10s: 11 -> 10",
			n:             11,
			expected:      10,
			minResolution: 1,
		},
		{
			desc:          "resolution of 1 truncates to 10s: 19 -> 10",
			n:             19,
			expected:      10,
			minResolution: 1,
		},
		{
			desc:          "supports message usage granularity (1000s): 9 -> 0",
			n:             9,
			expected:      0,
			minResolution: messageGranularity,
		},
		{
			desc:          "supports message usage granularity (1000s): 123 -> 100",
			n:             9,
			expected:      0,
			minResolution: messageGranularity,
		},
		{
			desc:          "supports message usage granularity (1000s): 1234 -> 1000",
			n:             1234,
			expected:      1000,
			minResolution: messageGranularity,
		},
		{
			desc:          "supports message usage granularity (1000s): 1500 -> 1000",
			n:             1500,
			expected:      1000,
			minResolution: messageGranularity,
		},
		{
			desc:          "supports file storage usage granularity (~100s of MiB): 13GiB -> 12.94GiB",
			n:             13 * 1024 * 1024 * 1024,
			expected:      13_900_000_000,
			minResolution: storageGranularity,
		},
		{
			desc:          "supports file storage usage granularity (~100s of MiB): 10GiB -> 9.965GiB",
			n:             10 * 1024 * 1024 * 1024,
			expected:      10_700_000_000,
			minResolution: storageGranularity,
		},
		{
			// first number at which usage reports as in excess of 10GiB.
			// Evaluates to 10299.5992MiB
			// Should be close enough for notifying of being over limit.
			desc:          "supports file storage usage granularity (~100s of MiB): 10.0583GiB -> 10.0583GiB",
			n:             10.0583 * 1024 * 1024 * 1024,
			expected:      10_800_000_000,
			minResolution: storageGranularity,
		},
		{
			desc:          "supports file storage usage granularity (~100s of MiB): 953.67MiB -> 953.67MiB",
			n:             1_000_000_000,
			expected:      1_000_000_000,
			minResolution: storageGranularity,
		},
		{
			desc:          "supports file storage usage granularity (~100s of MiB): 1GiB -> 953.67MiB",
			n:             1 * 1024 * 1024 * 1024,
			expected:      1_000_000_000,
			minResolution: storageGranularity,
		},
		{
			desc:          "supports file storage usage granularity (~100s of MiB): 1049.04MiB -> 1049.04MiB",
			n:             1_100_000_000,
			expected:      1_100_000_000,
			minResolution: storageGranularity,
		},
		{
			desc:          "supports file storage usage granularity (smaller amounts): 104.904MiB -> 104.904MiB",
			n:             100_000_000,
			expected:      100_000_000,
			minResolution: storageGranularity,
		},
		{
			desc:          "supports file storage usage granularity (smaller amounts): 10.4904MiB -> 10.4904MiB",
			n:             10_000_000,
			expected:      10_000_000,
			minResolution: storageGranularity,
		},
	}
	for _, tc := range testCases {
		t.Run(tc.desc, func(t *testing.T) {
			res := RoundOffToZeroesResolution(tc.n, tc.minResolution)
			assert.Equal(t, tc.expected, res)
		})
	}
}

func TestIsValidWebAuthRedirectURL(t *testing.T) {
	t.Run("Valid redirect URL with matching scheme and host", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com"),
			},
		}
		redirectURL := "https://example.com/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.True(t, result)
	})

	t.Run("Valid redirect URL with matching scheme and host with port", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com:8080"),
			},
		}
		redirectURL := "https://example.com:8080/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.True(t, result)
	})

	t.Run("Invalid redirect URL with different scheme", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com"),
			},
		}
		redirectURL := "http://example.com/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.False(t, result)
	})

	t.Run("Invalid redirect URL with different host", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com"),
			},
		}
		redirectURL := "https://malicious.com/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.False(t, result)
	})

	t.Run("Invalid redirect URL with different port", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com:8080"),
			},
		}
		redirectURL := "https://example.com:9090/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.False(t, result)
	})

	t.Run("Invalid redirect URL - malformed URL", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com"),
			},
		}
		redirectURL := "not-a-valid-url"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.False(t, result)
	})

	t.Run("Invalid config - nil SiteURL", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: nil,
			},
		}
		redirectURL := "https://example.com/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.False(t, result)
	})

	t.Run("Invalid config - malformed SiteURL", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("not-a-valid-url"),
			},
		}
		redirectURL := "https://example.com/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.False(t, result)
	})

	t.Run("Valid redirect URL with subdomain", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://app.example.com"),
			},
		}
		redirectURL := "https://app.example.com/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.True(t, result)
	})

	t.Run("Invalid redirect URL with different subdomain", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://app.example.com"),
			},
		}
		redirectURL := "https://api.example.com/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.False(t, result)
	})

	t.Run("Valid redirect URL with path", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com/mattermost"),
			},
		}
		redirectURL := "https://example.com/mattermost/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.True(t, result)
	})

	t.Run("Valid redirect URL with query parameters", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com"),
			},
		}
		redirectURL := "https://example.com/oauth/callback?state=abc123&code=def456"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.True(t, result)
	})

	t.Run("Valid redirect URL with fragment", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://example.com"),
			},
		}
		redirectURL := "https://example.com/oauth/callback#token=abc123"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.True(t, result)
	})

	t.Run("Invalid redirect URL with @ symbol in host", func(t *testing.T) {
		config := &model.Config{
			ServiceSettings: model.ServiceSettings{
				SiteURL: model.NewPointer("https://qa-release.test.mattermost.cloud"),
			},
		}
		redirectURL := "https://qa-release.test.mattermost.cloud@example.com/oauth/callback"

		result := IsValidWebAuthRedirectURL(config, redirectURL)
		assert.False(t, result)
	})
}