//! Typed failures and coarse process status allocation.

use std::collections::BTreeMap;

use schemars::JsonSchema;
use serde::{Deserialize, Serialize};
use serde_json::Value;
use thiserror::Error;

/// Stable machine-readable error taxonomy available in the foundation.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum ErrorCode {
    /// Command-line syntax or validation failed.
    InvalidArguments,
    /// The caller's Sample path does not exist.
    SampleNotFound,
    /// The caller's Sample cannot be read.
    SampleUnreadable,
    /// The opened Sample is not a regular file.
    InvalidSampleType,
    /// The Sample exceeded the selected byte ceiling.
    SampleTooLarge,
    /// Source metadata changed while snapshotting.
    SampleChanged,
    /// The Analysis Store lacks the required free-space reserve.
    InsufficientStoreSpace,
    /// Ghidra could not recognize a Target Specification.
    UnsupportedTarget,
    /// Ghidra found multiple Target Specification candidates.
    AmbiguousTarget,
    /// Ghidra is not installed.
    GhidraMissing,
    /// The installed Ghidra version is incompatible.
    GhidraIncompatible,
    /// Java is not installed.
    JavaMissing,
    /// The installed Java version is incompatible.
    JavaIncompatible,
    /// Rust/Java request or response validation failed.
    ProtocolViolation,
    /// The child exceeded a native or watchdog timeout.
    Timeout,
    /// Native auto-analysis timed out.
    AnalysisTimeout,
    /// Ghidra auto-analysis failed.
    AnalysisFailed,
    /// Native Function decompilation timed out.
    DecompileTimeout,
    /// Ghidra Function decompilation failed.
    DecompilationFailed,
    /// The caller interrupted the operation.
    Interrupted,
    /// The adapter could not serialize a bounded response.
    ResultTooLarge,
    /// The success descriptor cannot fit the requested inline budget.
    InlineBudgetTooSmall,
    /// Store-wide cleanup lacks explicit confirmation.
    ConfirmationRequired,
    /// Another process holds the selected Analysis lock.
    AnalysisBusy,
    /// Stored Analysis validation failed and recovery did not succeed.
    CorruptAnalysis,
    /// A cleanup transaction requires a recoverable retry.
    CleanupIncomplete,
    /// The resolved Analysis Store path is invalid.
    InvalidStorePath,
    /// A Function Selector resolved to no Function.
    FunctionNotFound,
    /// A Function Selector resolved to multiple Functions.
    FunctionSelectorAmbiguous,
    /// An Address is not a Function entry.
    FunctionEntryRequired,
    /// Ghidra does not contain the requested address space.
    AddressSpaceNotFound,
    /// Installation diagnosis found an unusable component.
    DoctorFailed,
    /// A general runtime or integration failure.
    Internal,
}

impl ErrorCode {
    /// Authoritative coarse status mapping from ADR 0002.
    #[must_use]
    pub const fn exit_status(self) -> ExitStatus {
        match self {
            Self::InvalidArguments => ExitStatus::InvalidInvocation,
            Self::Timeout | Self::AnalysisTimeout | Self::DecompileTimeout => ExitStatus::Timeout,
            Self::Interrupted => ExitStatus::Interrupted,
            _ => ExitStatus::RuntimeFailure,
        }
    }
}

/// Stable public error body.
#[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize, JsonSchema)]
pub struct ErrorBody {
    /// Stable machine identifier.
    pub code: ErrorCode,
    /// Concise context that is not a control-flow interface.
    pub message: String,
    /// Whether the same logical request might later succeed unchanged.
    pub retryable: bool,
    /// Code-specific structured context, always an object.
    pub details: BTreeMap<String, Value>,
}

/// Versioned failure document.
#[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize, JsonSchema)]
pub struct ErrorEnvelope {
    /// Public schema major version.
    pub schema_version: u32,
    /// Always `error`.
    pub kind: ErrorKind,
    /// Typed failure body.
    pub error: ErrorBody,
}

/// Error envelope discriminator.
#[derive(Clone, Copy, Debug, Eq, PartialEq, Serialize, Deserialize, JsonSchema)]
#[serde(rename_all = "snake_case")]
pub enum ErrorKind {
    /// A failed invocation.
    Error,
}

/// Internal error paired with its public document and status class.
#[derive(Clone, Debug, Error)]
#[error("{body_message}")]
pub struct AppError {
    body_message: String,
    envelope: ErrorEnvelope,
    status: ExitStatus,
}

impl AppError {
    /// Constructs a typed failure with empty structured details.
    #[must_use]
    pub fn new(code: ErrorCode, message: impl Into<String>, retryable: bool) -> Self {
        let message = message.into();
        let status = code.exit_status();
        Self {
            body_message: message.clone(),
            envelope: ErrorEnvelope {
                schema_version: 1,
                kind: ErrorKind::Error,
                error: ErrorBody {
                    code,
                    message,
                    retryable,
                    details: BTreeMap::new(),
                },
            },
            status,
        }
    }

    /// Constructs an invalid-invocation failure from clap context.
    #[must_use]
    pub fn invalid_arguments(message: impl Into<String>) -> Self {
        Self::new(ErrorCode::InvalidArguments, message, false)
    }

    /// Adds one typed detail field.
    #[must_use]
    pub fn with_detail(mut self, key: impl Into<String>, value: Value) -> Self {
        self.envelope.error.details.insert(key.into(), value);
        self
    }

    /// Returns the public error document.
    #[must_use]
    pub const fn envelope(&self) -> &ErrorEnvelope {
        &self.envelope
    }

    /// Returns the coarse process status.
    #[must_use]
    pub const fn status(&self) -> ExitStatus {
        self.status
    }
}

/// Accepted coarse process statuses from ADR 0002.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
#[repr(i32)]
pub enum ExitStatus {
    /// Successful operation.
    Success = 0,
    /// Runtime failure.
    RuntimeFailure = 1,
    /// Invalid invocation or arguments.
    InvalidInvocation = 2,
    /// Native phase or child watchdog timeout.
    Timeout = 124,
    /// User interruption.
    Interrupted = 130,
}

impl ExitStatus {
    /// Integer process exit code.
    #[must_use]
    pub const fn code(self) -> i32 {
        self as i32
    }
}

#[cfg(test)]
mod tests {
    use super::{ErrorCode, ExitStatus};

    #[test]
    fn detailed_errors_map_to_only_accepted_coarse_statuses() {
        assert_eq!(
            ErrorCode::InvalidArguments.exit_status(),
            ExitStatus::InvalidInvocation
        );
        assert_eq!(
            ErrorCode::AnalysisTimeout.exit_status(),
            ExitStatus::Timeout
        );
        assert_eq!(
            ErrorCode::Interrupted.exit_status(),
            ExitStatus::Interrupted
        );
        assert_eq!(
            ErrorCode::ProtocolViolation.exit_status(),
            ExitStatus::RuntimeFailure
        );
    }
}