use crate::{derive, hashing};
use bstr::{BStr, BString, ByteSlice as _};

// archives aren't sorted in any particular order, so we can just default these
/// The underlying hash object used to uniquely identify objects within the archive.
#[derive(Clone, Copy, Debug, Default, Eq, Ord, PartialEq, PartialOrd)]
#[repr(C)]
pub struct Hash {
    /// The file's stem crc.
    pub file: u32,
    /// The first 4 bytes of the file's extension.
    pub extension: u32,
    /// The file's parent path crc.
    pub directory: u32,
}

derive::hash!(FileHash);

impl Hash {
    #[must_use]
    pub fn new() -> Self {
        Self::default()
    }
}

#[allow(clippy::unreadable_literal)]
#[must_use]
fn crc32(bytes: &[u8]) -> u32 {
    const LUT: [u32; 256] = [
        0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535,
        0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD,
        0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D,
        0x6DDDE4EB, 0xF4D4B551, 0x83D385C7, 0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
        0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4,
        0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
        0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59, 0x26D930AC,
        0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
        0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB,
        0xB6662D3D, 0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F,
        0x9FBFE4A5, 0xE8B8D433, 0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB,
        0x086D3D2D, 0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
        0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA,
        0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65, 0x4DB26158, 0x3AB551CE,
        0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A,
        0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
        0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409,
        0xCE61E49F, 0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81,
        0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739,
        0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
        0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1, 0xF00F9344, 0x8708A3D2, 0x1E01F268,
        0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0,
        0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8,
        0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
        0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF,
        0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703,
        0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7,
        0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D, 0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
        0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE,
        0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
        0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777, 0x88085AE6,
        0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
        0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D,
        0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5,
        0x47B2CF7F, 0x30B5FFE9, 0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605,
        0xCDD70693, 0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
        0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D,
    ];

    let mut crc: u32 = 0;
    for &b in bytes {
        crc = crc.wrapping_shr(8) ^ LUT[((crc ^ u32::from(b)) & 0xFF) as usize];
    }
    crc
}

struct Split<'string> {
    parent: &'string BStr,
    stem: &'string BStr,
    extension: &'string BStr,
}

#[must_use]
fn split_path(path: &BStr) -> Split<'_> {
    let stem_pos = path.iter().rposition(|&x| x == b'\\');
    let parent = stem_pos.map(|pos| &path[0..pos]).unwrap_or_default();

    let extension_pos = path.iter().rposition(|&x| x == b'.');
    let extension = extension_pos
        .and_then(|pos| path.get(pos + 1..)) // don't include '.'
        .unwrap_or_default()
        .as_bstr();

    let first = stem_pos.map_or(0, |x| x + 1);
    let last = extension_pos.unwrap_or(path.len());
    let stem = path.get(first..last).unwrap_or_default().as_bstr();

    Split {
        parent,
        stem,
        extension,
    }
}

/// Produces a hash using the given path.
#[must_use]
pub fn hash_file(path: &BStr) -> (FileHash, BString) {
    let mut path = path.to_owned();
    (hash_file_in_place(&mut path), path)
}

/// Produces a hash using the given path.
///
/// The path is normalized in place. After the function returns, the path contains the string that would be stored on disk.
#[must_use]
pub fn hash_file_in_place(path: &mut BString) -> FileHash {
    hashing::normalize_path(path);
    let pieces = split_path(path.as_ref());

    let mut h = Hash {
        file: crc32(pieces.stem),
        extension: 0,
        directory: crc32(pieces.parent),
    };

    // truncation is impossible here
    #[allow(clippy::cast_possible_truncation)]
    let len = { usize::min(pieces.extension.len(), 4) as u32 };
    for i in 0..len {
        h.extension |= u32::from(pieces.extension[i as usize]) << (i * 8);
    }

    h.into()
}

#[cfg(test)]
mod tests {
    use crate::fo4::{self, Hash};
    use bstr::ByteSlice as _;

    #[test]
    fn default_state() {
        let h = Hash::default();
        assert_eq!(h.file, 0);
        assert_eq!(h.extension, 0);
        assert_eq!(h.directory, 0);
    }

    #[test]
    fn validate_hashes() {
        let l = |path: &[u8]| fo4::hash_file(path.as_bstr()).0;
        let r = |file: u32, extension: u32, directory: u32| Hash {
            file,
            extension,
            directory,
        };

        assert_eq!(
            l(b"Sound\\Voice\\Fallout4.esm\\RobotMrHandy\\Mar\xEDa_M.fuz"),
            r(0xC9FB26F9, 0x007A7566, 0x8A9C014E)
        );
        assert_eq!(
            l(br"Strings\ccBGSFO4001-PipBoy(Black)_en.DLSTRINGS"),
            r(0x1985075C, 0x74736C64, 0x29F6B58B)
        );
        assert_eq!(
            l(br"Textures\CreationClub\BGSFO4001\AnimObjects\PipBoy\PipBoy02(Black)_d.DDS"),
            r(0x69E1E82C, 0x00736464, 0x23157A84)
        );
        assert_eq!(
            l(br"Materials\CreationClub\BGSFO4003\AnimObjects\PipBoy\PipBoyLabels01(Camo01).BGSM"),
            r(0x0785843B, 0x6D736762, 0x818374CC)
        );
        assert_eq!(
            l(br"Textures\CreationClub\BGSFO4003\AnimObjects\PipBoy\PipBoy02(Camo01)_d.DDS"),
            r(0xF2D2F9A7, 0x00736464, 0xE9DB0C08)
        );
        assert_eq!(
            l(br"Strings\ccBGSFO4004-PipBoy(Camo02)_esmx.DLSTRINGS"),
            r(0xC26B77C1, 0x74736C64, 0x29F6B58B)
        );
        assert_eq!(
            l(br"Textures\CreationClub\BGSFO4004\AnimObjects\PipBoy\PipBoyLabels01(Camo02)_d.DDS"),
            r(0xB32EE4B0, 0x00736464, 0x089FAA9B)
        );
        assert_eq!(
            l(br"Strings\ccBGSFO4006-PipBoy(Chrome)_es.STRINGS"),
            r(0xA94A4503, 0x69727473, 0x29F6B58B)
        );
        assert_eq!(
            l(br"Textures\CreationClub\BGSFO4006\AnimObjects\PipBoy\PipBoy01(Chrome)_s.DDS"),
            r(0xE2D67EE2, 0x00736464, 0xC251DC17)
        );
        assert_eq!(
            l(br"Meshes\CreationClub\BGSFO4016\Clothes\Prey\MorganSpaceSuit_M_First.nif"),
            r(0x212E5DAD, 0x0066696E, 0x741DAAC0)
        );
        assert_eq!(
            l(br"Textures\CreationClub\BGSFO4016\Clothes\Prey\Morgan_Male_Body_s.DDS"),
            r(0x9C672F34, 0x00736464, 0x1D5F0EDF)
        );
        assert_eq!(
            l(br"Strings\ccBGSFO4018-GaussRiflePrototype_ru.STRINGS"),
            r(0x5198717F, 0x69727473, 0x29F6B58B)
        );
        assert_eq!(
            l(br"Textures\CreationClub\BGSFO4018\Weapons\GaussRiflePrototype\Barrel02_s.DDS"),
            r(0x2C98BAA2, 0x00736464, 0x8D59E9EA)
        );
        assert_eq!(
            l(br"Strings\ccBGSFO4019-ChineseStealthArmor_esmx.DLSTRINGS"),
            r(0xDDF2A35F, 0x74736C64, 0x29F6B58B)
        );
        assert_eq!(l(br"Textures\CreationClub\BGSFO4019\Armor\ChineseStealthArmor\ChineseStealthArmor01_d.DDS"), r(0x03C2AA10, 0x00736464, 0x71ED2818));
        assert_eq!(
            l(br"Materials\CreationClub\BGSFO4020\Actors\PowerArmor\T45helmet01(Black).BGSM"),
            r(0xF56D31C0, 0x6D736762, 0x28A143A5)
        );
        assert_eq!(l(br"Textures\CreationClub\BGSFO4020\Actors\PowerArmor\T51\Black\T51Helmet01(Black)_d.DDS"), r(0x3192919D, 0x00736464, 0xA56D1E61));
        assert_eq!(
            l(br"Materials\CreationClub\BGSFO4038\Actors\PowerArmor\HorsePAHelmet.BGSM"),
            r(0xE90B72CC, 0x6D736762, 0x44676566)
        );
        assert_eq!(
            l(br"Textures\CreationClub\BGSFO4038\Actors\PowerArmor\HorsePATorso_teal_d.DDS"),
            r(0x0A6251B3, 0x00736464, 0xC1AC59B4)
        );
        assert_eq!(
            l(br"Strings\ccBGSFO4044-HellfirePowerArmor_en.DLSTRINGS"),
            r(0x3E5C1E5E, 0x74736C64, 0x29F6B58B)
        );
        assert_eq!(l(br"Textures\CreationClub\BGSFO4044\Actors\PowerArmor\HellfirePAHelmet_Institute_d.DDS"), r(0x0F221EAF, 0x00736464, 0xC021EF40));
        assert_eq!(
            l(br"Meshes\Weapons\HandmadeShotgun\HandmadeShotgun_GlowSights.nif"),
            r(0x4E080CE2, 0x0066696E, 0xCCD47ECF)
        );
        assert_eq!(
            l(br"Textures\Weapons\HandmadeShotgun\HandmadeShotgun_Barrels_GhoulSlayer_d.DDS"),
            r(0xBBFC484C, 0x00736464, 0xCEAE4154)
        );
        assert_eq!(l(br"Materials\CreationClub\FSVFO4001\Clothes\MilitaryBackpack\BackpackPatch_NCR02.bgsm"), r(0x90EB78B9, 0x6D736762, 0xDA685DF4));
        assert_eq!(l(br"Textures\CreationClub\FSVFO4001\Clothes\MilitaryBackpack\Button_SunsetSars_d.DDS"), r(0xC25F8604, 0x00736464, 0xD1CE178D));
        assert_eq!(
            l(br"Materials\CreationClub\FSVFO4002\Furniture\MidCenturyModern01\BedSpread01.bgsm"),
            r(0xA5AAE799, 0x6D736762, 0xBECD0DEF)
        );
        assert_eq!(
            l(br"Textures\CreationClub\FSVFO4002\Furniture\MidCenturyModern01\Bed01_n.DDS"),
            r(0x6A09686A, 0x00736464, 0xBA782808)
        );
        assert_eq!(
            l(br"Sound\FX\DLC03\NPC\Gulper\NPC_Gulper_Foot_Walk_02.xwm"),
            r(0xFE001981, 0x006D7778, 0xE7FBD6C4)
        );
        assert_eq!(
            l(br"Textures\Terrain\DLC03FarHarbor\DLC03FarHarbor.4.-69.41.DDS"),
            r(0x36BACD03, 0x00736464, 0x8184624D)
        );
        assert_eq!(
            l(br"Sound\Voice\DLCCoast.esm\PlayerVoiceFemale01\00043FFC_1.fuz"),
            r(0x339EFB3F, 0x007A7566, 0x3A5289D4)
        );
        assert_eq!(
            l(br"Meshes\PreCombined\DLCNukaWorld.esm\0000F616_17EAC297_OC.NIF"),
            r(0xD4AD97F7, 0x0066696E, 0x0787B7E9)
        );
        assert_eq!(
            l(br"Textures\Terrain\NukaWorld\NukaWorld.4.-28.28_msn.DDS"),
            r(0x86C13103, 0x00736464, 0x26C08933)
        );
        assert_eq!(
            l(br"Sound\Voice\DLCNukaWorld.esm\DLC04NPCMJohnCalebBradberton\00044D5E_1.fuz"),
            r(0x896E4419, 0x007A7566, 0xD6575CD6)
        );
        assert_eq!(
            l(br"Meshes\SCOL\DLCRobot.esm\CM00007BD8.NIF"),
            r(0x103559EF, 0x0066696E, 0xF584B7C4)
        );
        assert_eq!(
            l(br"Textures\DLC01\SetDressing\Rubble\Robottrashpilesnorust_s.DDS"),
            r(0xC7AF7106, 0x00736464, 0x5FD1A1B0)
        );
        assert_eq!(
            l(br"Sound\Voice\DLCRobot.esm\DLC01RobotCompanionFemaleProcessed\00001460_1.fuz"),
            r(0x6D3D7DC7, 0x007A7566, 0xB2B47CAD)
        );
        assert_eq!(
            l(br"Materials\DLC02\SetDressing\Workshop\NeonSignage\NeonLetterKit01-Orange-5.BGEM"),
            r(0x21D59551, 0x6D656762, 0x926F0C27)
        );
        assert_eq!(
            l(br"Textures\DLC02\SetDressing\Workshop\Traps\DLC02_SpringTrap01_s.DDS"),
            r(0x02BE99A4, 0x00736464, 0xF03CA2DF)
        );
        assert_eq!(
            l(br"Sound\FX\DLC05\PHY\BallTrack\PHY_Metal_BallTrack_SteelBall_Wood_H_03.xwm"),
            r(0x33AABE0C, 0x006D7778, 0x07AA294C)
        );
        assert_eq!(
            l(br"Textures\DLC05\Effects\PaintBalls\ImpactDecalPaintSplatters01Red_d.DDS"),
            r(0x6327DF24, 0x00736464, 0xFB5FB431)
        );
        assert_eq!(
            l(br"Meshes\SCOL\DLCworkshop03.esm\CM00001091.NIF"),
            r(0x2CAF6750, 0x0066696E, 0xABA83647)
        );
        assert_eq!(
            l(br"Textures\DLC06\Interiors\Vault\DLC06VltSignWelcome88_01_d.DDS"),
            r(0x825BD732, 0x00736464, 0xAE76DDEF)
        );
        assert_eq!(
            l(br"Sound\Voice\DLCworkshop03.esm\FemaleEvenToned\00005232_1.fuz"),
            r(0x4DB6EE2D, 0x007A7566, 0xDA9F7ABC)
        );
        assert_eq!(
            l(br"Meshes\AnimTextData\DynamicIdleData\5693375383928345500.txt"),
            r(0x997FC17A, 0x00747874, 0xFD345C50)
        );
        assert_eq!(
            l(br"Interface\Pipboy_StatsPage.swf"),
            r(0x2F26E4D0, 0x00667773, 0xD2FDF873)
        );
        assert_eq!(
            l(br"Materials\Landscape\Grass\BeachGrass01.BGSM"),
            r(0xB023CE22, 0x6D736762, 0x941D851F)
        );
        assert_eq!(
            l(br"Meshes\Actors\Character\FaceGenData\FaceGeom\Fallout4.esm\000B3EC7.NIF"),
            r(0x90C91640, 0x0066696E, 0x067FA81E)
        );
        assert_eq!(
            l(br"Meshes\PreCombined\0000E069_7831AAC9_OC.NIF"),
            r(0x5F0B19DF, 0x0066696E, 0xE659D075)
        );
        assert_eq!(
            l(br"scripts\MinRadiantOwnedBuildResourceScript.pex"),
            r(0xA2DAD4FD, 0x00786570, 0x40724840)
        );
        assert_eq!(
            l(br"Meshes\debris\roundrock2_dirt.nif"),
            r(0x1E47A158, 0x0066696E, 0xF55EC6BA)
        );
        assert_eq!(
            l(br"ShadersFX\Shaders011.fxp"),
            r(0x883415D8, 0x00707866, 0xDFAE3D0F)
        );
        assert_eq!(
            l(br"Sound\FX\FX\Bullet\Impact\xxx\FX_Bullet_Impact_Dirt_04.xwm"),
            r(0xFFAD9A14, 0x006D7778, 0xCBA20EB7)
        );
        assert_eq!(
            l(br"Textures\Effects\ColorBlackZeroAlphaUtility.DDS"),
            r(0xF912F225, 0x00736464, 0xEA3C9738)
        );
        assert_eq!(
            l(br"Textures\interiors\Building\BldWindow01_s.DDS"),
            r(0x6ECA4F0C, 0x00736464, 0x5A3A7C7A)
        );
        assert_eq!(
            l(br"Textures\Terrain\Commonwealth\Commonwealth.4.-8.12_msn.DDS"),
            r(0x55E37BD8, 0x00736464, 0x4409E1A9)
        );
        assert_eq!(
            l(br"Textures\Clothes\Nat\Nats_Outfit_s.DDS"),
            r(0x692FFE7D, 0x00736464, 0x3F5BEDF1)
        );
        assert_eq!(
            l(br"Textures\Interface\Newspaper\Newspaper_s.DDS"),
            r(0xFAC17C6C, 0x00736464, 0x58B9C5A4)
        );
        assert_eq!(
            l(br"Textures\Actors\Character\FaceCustomization\Fallout4.esm\00110043_s.DDS"),
            r(0x09A155E6, 0x00736464, 0x9C7DFA7A)
        );
        assert_eq!(
            l(br"Textures\Terrain\Commonwealth\Commonwealth.4.-48.-60.DDS"),
            r(0x182C2446, 0x00736464, 0x4409E1A9)
        );
        assert_eq!(
            l(br"Textures\Terrain\Commonwealth\Commonwealth.4.-80.8_msn.DDS"),
            r(0xDA3234A4, 0x00736464, 0x4409E1A9)
        );
        assert_eq!(
            l(br"Textures\Terrain\SanctuaryHillsWorld\SanctuaryHillsWorld.4.-36.40.DDS"),
            r(0xDD27070A, 0x00736464, 0x49AAA5E1)
        );
        assert_eq!(
            l(br"Textures\Terrain\SanctuaryHillsWorld\SanctuaryHillsWorld.4.76.-24.DDS"),
            r(0x71560B31, 0x00736464, 0x49AAA5E1)
        );
        assert_eq!(
            l(br"Sound\Voice\Fallout4.esm\NPCMTravisMiles\000A6032_1.fuz"),
            r(0x34402DE0, 0x007A7566, 0xF186D761)
        );
    }
}