// file: crates/ksp-program-api/tests/external_implementation.rs
// version: 1

//! Downstream-style implementation canary for the open Program decoder contract.

const EXTERNAL_PROGRAM_ID_BYTES: [u8; 32] = [0xE7_u8; 32];
const FOREIGN_PROGRAM_ID_BYTES: [u8; 32] = [0xE8_u8; 32];
const SUPPORTED_OPCODE: u8 = 0x2A_u8;

struct ExternalDecodedInstruction {
    opcode: u8,
}

struct ExternalProgramDecoder {
    program_ids: [ksp_program_api::Pubkey; 1],
}

impl ExternalProgramDecoder {
    fn new() -> Self {
        return Self { program_ids: [ksp_program_api::Pubkey::new_from_array(EXTERNAL_PROGRAM_ID_BYTES)] };
    }
}

impl ksp_program_api::ProgramInstructionDecoder for ExternalProgramDecoder {
    type Decoded = ExternalDecodedInstruction;

    fn program_ids(&self) -> &[ksp_program_api::Pubkey] {
        return &self.program_ids;
    }

    fn recognize(&self, instruction: &ksp_program_api::ProgramInstruction) -> ksp_program_api::ProgramInstructionRecognition {
        if instruction.program_id() != &self.program_ids[0] {
            return ksp_program_api::ProgramInstructionRecognition::NoMatch;
        }
        if instruction.data().first() == std::option::Option::Some(&SUPPORTED_OPCODE) {
            return ksp_program_api::ProgramInstructionRecognition::ExactMatch;
        }
        return ksp_program_api::ProgramInstructionRecognition::ProgramMatch;
    }

    fn decode(
        &self,
        instruction: &ksp_program_api::ProgramInstruction,
    ) -> ksp_program_api::Result<ksp_program_api::ProgramInstructionDecodeOutcome<Self::Decoded>> {
        if instruction.program_id() != &self.program_ids[0] {
            return std::result::Result::Ok(ksp_program_api::ProgramInstructionDecodeOutcome::Unsupported);
        }
        let opcode = match instruction.data().first() {
            std::option::Option::Some(value) if *value == SUPPORTED_OPCODE => *value,
            _ => return std::result::Result::Ok(ksp_program_api::ProgramInstructionDecodeOutcome::Unsupported),
        };
        return std::result::Result::Ok(ksp_program_api::ProgramInstructionDecodeOutcome::Decoded(ExternalDecodedInstruction { opcode }));
    }
}

fn assert_send_sync<T: Send + Sync>(_value: &T) {
    return;
}

#[test]
fn pre_004_external_decoder_uses_unregistered_pubkey_and_implementation_owned_output() {
    let decoder = ExternalProgramDecoder::new();
    assert_send_sync(&decoder);
    let external_program_id = ksp_program_api::Pubkey::new_from_array(EXTERNAL_PROGRAM_ID_BYTES);
    assert!(ksp_core_lib::find_program_pubkey(&external_program_id).is_none());
    assert_eq!(ksp_program_api::ProgramInstructionDecoder::program_ids(&decoder), &[external_program_id]);
    let exact = ksp_program_api::ProgramInstruction::try_new(external_program_id, std::vec![], std::vec![SUPPORTED_OPCODE]);
    assert!(exact.is_ok());
    let exact = match exact {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(_) => return,
    };
    assert_eq!(ksp_program_api::ProgramInstructionDecoder::recognize(&decoder, &exact), ksp_program_api::ProgramInstructionRecognition::ExactMatch);
    let outcome = ksp_program_api::ProgramInstructionDecoder::decode(&decoder, &exact);
    assert!(outcome.is_ok());
    let outcome = match outcome {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(_) => return,
    };
    let decoded = match outcome {
        ksp_program_api::ProgramInstructionDecodeOutcome::Decoded(value) => value,
        _ => return,
    };
    assert_eq!(decoded.opcode, SUPPORTED_OPCODE);
    return;
}

#[test]
fn pre_004_external_decoder_distinguishes_program_match_unsupported_and_no_match() {
    let decoder = ExternalProgramDecoder::new();
    let external_program_id = ksp_program_api::Pubkey::new_from_array(EXTERNAL_PROGRAM_ID_BYTES);
    let program_only = ksp_program_api::ProgramInstruction::try_new(external_program_id, std::vec![], std::vec![0x11_u8]);
    assert!(program_only.is_ok());
    let program_only = match program_only {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(_) => return,
    };
    assert_eq!(ksp_program_api::ProgramInstructionDecoder::recognize(&decoder, &program_only), ksp_program_api::ProgramInstructionRecognition::ProgramMatch);
    let unsupported = ksp_program_api::ProgramInstructionDecoder::decode(&decoder, &program_only);
    assert!(unsupported.is_ok());
    let unsupported = match unsupported {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(_) => return,
    };
    assert!(matches!(unsupported, ksp_program_api::ProgramInstructionDecodeOutcome::Unsupported));
    let foreign_program_id = ksp_program_api::Pubkey::new_from_array(FOREIGN_PROGRAM_ID_BYTES);
    let foreign = ksp_program_api::ProgramInstruction::try_new(foreign_program_id, std::vec![], std::vec![SUPPORTED_OPCODE]);
    assert!(foreign.is_ok());
    let foreign = match foreign {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(_) => return,
    };
    assert_eq!(ksp_program_api::ProgramInstructionDecoder::recognize(&decoder, &foreign), ksp_program_api::ProgramInstructionRecognition::NoMatch);
    return;
}