package com.peachpasswords.ui.security

import org.junit.Assert.assertEquals
import org.junit.Assert.assertTrue
import org.junit.Test

/**
 * Behavioural contract for the shared strength scorer. These assertions pin the
 * two gates the app relies on: CreateVault blocks `< 2`, ExportScreen blocks
 * `< 3`. They are intentionally inequality-based where the exact bucket is not
 * load-bearing, and exact where a boundary matters.
 */
class PasswordStrengthTest {

    @Test fun empty_scores_zero() {
        assertEquals(0, scorePassword(""))
    }

    @Test fun single_repeated_char_scores_zero() {
        assertEquals(0, scorePassword("aaaaaaaaaaaa"))
    }

    @Test fun common_passwords_score_zero_case_insensitive() {
        assertEquals(0, scorePassword("password"))
        assertEquals(0, scorePassword("Password"))
        assertEquals(0, scorePassword("PASSWORD"))
        assertEquals(0, scorePassword("123456"))
        assertEquals(0, scorePassword("qwerty"))
        assertEquals(0, scorePassword("peach"))
    }

    @Test fun short_single_class_is_weak() {
        // 8 lowercase letters: real but low-entropy → "weak" (1), below both gates.
        assertTrue(scorePassword("abcdefgh") < 2)
    }

    @Test fun straight_sequence_is_penalized() {
        // Pure ascending run collapses toward zero entropy.
        assertTrue(scorePassword("abcdefghij") < 2)
        assertTrue(scorePassword("0123456789") < 2)
    }

    @Test fun mixed_8char_three_class_passes_create_gate() {
        // "short1A!" — lower+upper+digit+symbol, length 8 → "fair" (2).
        assertTrue(scorePassword("short1A!") >= 2)
    }

    @Test fun mixed_12char_four_class_is_strong_and_passes_export_gate() {
        assertTrue(scorePassword("xK9#mQ2vL8wR") >= 3)
        assertTrue(scorePassword("Password123!") >= 3)
    }

    @Test fun long_passphrase_is_strong() {
        assertEquals(4, scorePassword("correcthorsebatterystaple"))
    }

    @Test fun score_is_always_in_range() {
        val samples = listOf(
            "", "a", "ab", "abc123", "Tr0ub4dor&3", "                ",
            "P@ssw0rd!2024xyz", "hunter2", "my secret diary 2024",
        )
        for (pw in samples) {
            val s = scorePassword(pw)
            assertTrue("score for '$pw' = $s out of range", s in 0..4)
        }
    }

    @Test fun labels_cover_full_range_and_clamp() {
        assertEquals("very weak", strengthLabel(0))
        assertEquals("weak", strengthLabel(1))
        assertEquals("fair", strengthLabel(2))
        assertEquals("good", strengthLabel(3))
        assertEquals("strong", strengthLabel(4))
        // Out-of-range inputs clamp rather than crash.
        assertEquals("very weak", strengthLabel(-1))
        assertEquals("strong", strengthLabel(99))
    }

    @Test fun more_length_never_lowers_a_clean_password() {
        // Monotonic-ish sanity: extending a varied password should not drop it
        // below the create gate.
        val base = "Xk9#mQ2v"
        assertTrue(scorePassword(base + "L8wR") >= scorePassword(base))
    }
}