// file: crates/ksp-config-lib/src/logging.rs
// version: 2

/// Effective standard Logging configuration resolved from Config and mapped to the Logging runtime contract.
#[derive(Clone, Eq, PartialEq)]
pub struct ResolvedLoggingConfig {
    file_id: crate::ConfigFileId,
    source_path: std::path::PathBuf,
    profile_id: String,
    selection_source: crate::ConfigProfileSelectionSource,
    effective: crate::ResolvedConfigJson,
    logs_directory: std::path::PathBuf,
    settings: ksp_logging_lib::LoggingSettings,
}

impl ResolvedLoggingConfig {
    /// Returns the logical Config document identifier used by this runtime configuration.
    #[must_use]
    pub const fn file_id(&self) -> &crate::ConfigFileId {
        return &self.file_id;
    }

    /// Returns the physical source Config document path.
    #[must_use]
    pub fn source_path(&self) -> &std::path::Path {
        return self.source_path.as_path();
    }

    /// Returns the selected standard Logging profile identifier.
    #[must_use]
    pub fn profile_id(&self) -> &str {
        return self.profile_id.as_str();
    }

    /// Returns the source that selected the standard Logging profile.
    #[must_use]
    pub const fn selection_source(&self) -> crate::ConfigProfileSelectionSource {
        return self.selection_source;
    }

    /// Returns the detailed environment-resolved effective Config view.
    ///
    /// The real tree is available to legitimate runtime consumers and the safe tree is suitable for ordinary diagnostics.
    #[must_use]
    pub const fn effective(&self) -> &crate::ResolvedConfigJson {
        return &self.effective;
    }

    /// Returns the validated real Logging root directory.
    ///
    /// Relative Config values are anchored to the process current working directory when this adapter runs. Absolute Config values are preserved.
    #[must_use]
    pub fn logs_directory(&self) -> &std::path::Path {
        return self.logs_directory.as_path();
    }

    /// Returns the mapped runtime Logging settings.
    #[must_use]
    pub const fn settings(&self) -> &ksp_logging_lib::LoggingSettings {
        return &self.settings;
    }

    /// Consumes this resolved Config and returns the mapped runtime Logging settings.
    #[must_use]
    pub fn into_settings(self) -> ksp_logging_lib::LoggingSettings {
        return self.settings;
    }
}

impl std::fmt::Debug for ResolvedLoggingConfig {
    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        return formatter
            .debug_struct("ResolvedLoggingConfig")
            .field("file_id", &self.file_id)
            .field("source_path", &self.source_path)
            .field("profile_id", &self.profile_id)
            .field("selection_source", &self.selection_source)
            .field("effective", &self.effective)
            .finish_non_exhaustive();
    }
}

impl crate::ConfigDocumentEngine {
    /// Loads the standard Logging document, selects a profile, resolves environment placeholders and maps the effective result to `LoggingSettings`.
    ///
    /// `requested_profile = None` uses the document `default_profile`; `Some(profile_id)` requests an explicit profile. Source JSON validation remains distinct
    /// from effective runtime validation: an environment value that resolves to an invalid Logging setting returns
    /// [`crate::ERROR_CODE_EFFECTIVE_CONFIG_INVALID`] and does not silently fall back to the placeholder fallback.
    pub fn load_resolved_logging_config(
        &self,
        requested_profile: std::option::Option<&str>,
        environment: &crate::ConfigEnvironment,
    ) -> ksp_core_lib::Result<ResolvedLoggingConfig> {
        let file_id = crate::ConfigFileId::new(crate::FILE_ID_STD_LOGGING);
        let file_id = match file_id {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error),
        };
        let profile = self.load_resolved_profile(&file_id, requested_profile);
        let profile = match profile {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error),
        };
        return resolve_logging_profile(&profile, environment);
    }

    /// Maps an already resolved standard Logging profile to the runtime Logging adapter while preserving its selection provenance.
    ///
    /// This entry point is intended for profiles selected by a composite. The profile must reference `cfg.std.logging`.
    pub fn resolve_logging_config_profile(
        &self,
        profile: &crate::ResolvedConfigProfile,
        environment: &crate::ConfigEnvironment,
    ) -> ksp_core_lib::Result<ResolvedLoggingConfig> {
        if profile.file_id().as_str() != crate::FILE_ID_STD_LOGGING {
            return std::result::Result::Err(effective_error(profile, "resolved Config profile does not reference the standard Logging document"));
        }
        let descriptor = self.registry().descriptor(profile.file_id());
        if let std::result::Result::Err(error) = descriptor {
            return std::result::Result::Err(error);
        }
        return resolve_logging_profile(profile, environment);
    }
}

#[derive(serde::Deserialize)]
#[serde(deny_unknown_fields)]
struct EffectiveLoggingSource {
    format_version: u32,
    logs_directory: String,
    profile_id: String,
    default_filter: String,
    span_events: String,
    console: EffectiveConsoleSource,
    files: std::vec::Vec<EffectiveFileSource>,
    target_filters: std::vec::Vec<EffectiveTargetFilterSource>,
}

#[derive(serde::Deserialize)]
#[serde(deny_unknown_fields)]
struct EffectiveConsoleSource {
    enabled: bool,
    output: String,
    ansi: bool,
    format: String,
    filter: EffectiveOutputFilterSource,
}

#[derive(serde::Deserialize)]
#[serde(deny_unknown_fields)]
struct EffectiveFileSource {
    output_id: String,
    enabled: bool,
    path: String,
    rotation: String,
    format: String,
    ansi: bool,
    filter: EffectiveOutputFilterSource,
}

#[derive(serde::Deserialize)]
#[serde(deny_unknown_fields)]
struct EffectiveOutputFilterSource {
    level: String,
    targets: std::vec::Vec<String>,
    domains: std::vec::Vec<String>,
}

#[derive(serde::Deserialize)]
#[serde(deny_unknown_fields)]
struct EffectiveTargetFilterSource {
    target_prefix: String,
    level: String,
}

fn resolve_logging_profile(profile: &crate::ResolvedConfigProfile, environment: &crate::ConfigEnvironment) -> ksp_core_lib::Result<ResolvedLoggingConfig> {
    let effective = profile.resolve_effective_environment_detailed(environment);
    let effective = match effective {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let sensitivity_validation = validate_logging_sensitivity(profile, &effective);
    if let std::result::Result::Err(error) = sensitivity_validation {
        return std::result::Result::Err(error);
    }
    let source = serde_json::from_value::<EffectiveLoggingSource>(effective.value().clone());
    let source = match source {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => {
            return std::result::Result::Err(
                effective_error(profile, "effective Logging Config cannot be decoded into the runtime adapter contract").with_source(error),
            );
        },
    };
    if source.format_version != 1 {
        return std::result::Result::Err(effective_error(profile, "effective Logging format_version is unsupported"));
    }
    if source.profile_id != profile.profile_id() {
        return std::result::Result::Err(effective_error(profile, "effective Logging profile_id differs from the selected source profile"));
    }
    let safe_logs_directory = safe_string_at(effective.safe_value(), "/logs_directory");
    let logs_directory = resolve_logs_directory(source.logs_directory.as_str(), safe_logs_directory.as_str(), profile);
    let logs_directory = match logs_directory {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let default_filter = map_level(source.default_filter.as_str(), "default_filter", profile);
    let default_filter = match default_filter {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let span_events = map_span_events(source.span_events.as_str(), profile);
    let span_events = match span_events {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let console = map_console(source.console, profile);
    let console = match console {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let files = map_files(source.files, logs_directory.as_path(), profile);
    let files = match files {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let mut settings = ksp_logging_lib::LoggingSettings::new(default_filter, span_events, std::option::Option::Some(console), files);
    for target_filter in source.target_filters {
        let level = map_level(target_filter.level.as_str(), "target_filters.level", profile);
        let level = match level {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error),
        };
        settings = settings.with_target_filter(ksp_logging_lib::TargetFilter::new(target_filter.target_prefix, level));
    }
    let validation = settings.validate();
    if let std::result::Result::Err(error) = validation {
        return std::result::Result::Err(
            effective_error(profile, "effective Logging settings fail the Logging runtime contract")
                .with_context("logging_error_domain", error.code().domain())
                .with_context("logging_error_code", error.code().code()),
        );
    }
    return std::result::Result::Ok(ResolvedLoggingConfig {
        file_id: profile.file_id().clone(),
        source_path: profile.path().to_path_buf(),
        profile_id: profile.profile_id().to_owned(),
        selection_source: profile.selection_source(),
        effective,
        logs_directory,
        settings,
    });
}

fn validate_logging_sensitivity(profile: &crate::ResolvedConfigProfile, effective: &crate::ResolvedConfigJson) -> ksp_core_lib::Result<()> {
    if effective.sensitivity().is_secret() {
        return std::result::Result::Err(effective_error(profile, "standard Logging configuration must not consume Secret environment values"));
    }
    return std::result::Result::Ok(());
}

fn map_console(source: EffectiveConsoleSource, profile: &crate::ResolvedConfigProfile) -> ksp_core_lib::Result<ksp_logging_lib::ConsoleSettings> {
    let output = match source.output.as_str() {
        "stdout" => ksp_logging_lib::ConsoleOutput::Stdout,
        "stderr" => ksp_logging_lib::ConsoleOutput::Stderr,
        _ => return std::result::Result::Err(effective_field_error(profile, "console.output", "effective Logging console output is unsupported")),
    };
    let format = map_format(source.format.as_str(), "console.format", profile);
    let format = match format {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    let filter = map_output_filter(source.filter, "console.filter", profile);
    let filter = match filter {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    return std::result::Result::Ok(ksp_logging_lib::ConsoleSettings::new(source.enabled, output, source.ansi, format, filter));
}

fn map_files(
    sources: std::vec::Vec<EffectiveFileSource>,
    logs_directory: &std::path::Path,
    profile: &crate::ResolvedConfigProfile,
) -> ksp_core_lib::Result<std::vec::Vec<ksp_logging_lib::FileSettings>> {
    let mut files = std::vec::Vec::<ksp_logging_lib::FileSettings>::with_capacity(sources.len());
    for source in sources {
        if !relative_file_path_is_valid(source.path.as_str()) {
            return std::result::Result::Err(
                effective_field_error(profile, "files.path", "effective Logging file path must stay relative to logs_directory without traversal")
                    .with_context("output_id", source.output_id.as_str()),
            );
        }
        let file_path = std::path::Path::new(source.path.as_str());
        let file_name = match file_path.file_name().and_then(std::ffi::OsStr::to_str) {
            std::option::Option::Some(value) if !value.is_empty() => value.to_owned(),
            _ => return std::result::Result::Err(effective_field_error(profile, "files.path", "effective Logging file path has no UTF-8 file name")),
        };
        let relative_directory = match file_path.parent() {
            std::option::Option::Some(value) => value,
            std::option::Option::None => std::path::Path::new(""),
        };
        let directory = logs_directory.join(relative_directory);
        let rotation = map_rotation(source.rotation.as_str(), profile);
        let rotation = match rotation {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error),
        };
        let format = map_format(source.format.as_str(), "files.format", profile);
        let format = match format {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error),
        };
        let filter = map_output_filter(source.filter, "files.filter", profile);
        let filter = match filter {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => return std::result::Result::Err(error),
        };
        let file = ksp_logging_lib::FileSettings::new(source.output_id, source.enabled, directory, file_name, rotation, format, filter).with_ansi(source.ansi);
        files.push(file);
    }
    return std::result::Result::Ok(files);
}

fn map_output_filter(
    source: EffectiveOutputFilterSource,
    field: &'static str,
    profile: &crate::ResolvedConfigProfile,
) -> ksp_core_lib::Result<ksp_logging_lib::OutputFilter> {
    let level = map_level(source.level.as_str(), field, profile);
    let level = match level {
        std::result::Result::Ok(value) => value,
        std::result::Result::Err(error) => return std::result::Result::Err(error),
    };
    return std::result::Result::Ok(ksp_logging_lib::OutputFilter::new(level, source.targets, source.domains));
}

fn map_level(value: &str, field: &'static str, profile: &crate::ResolvedConfigProfile) -> ksp_core_lib::Result<ksp_logging_lib::LogFilterLevel> {
    return match value {
        "off" => std::result::Result::Ok(ksp_logging_lib::LogFilterLevel::Off),
        "error" => std::result::Result::Ok(ksp_logging_lib::LogFilterLevel::Error),
        "warn" => std::result::Result::Ok(ksp_logging_lib::LogFilterLevel::Warn),
        "info" => std::result::Result::Ok(ksp_logging_lib::LogFilterLevel::Info),
        "debug" => std::result::Result::Ok(ksp_logging_lib::LogFilterLevel::Debug),
        "trace" => std::result::Result::Ok(ksp_logging_lib::LogFilterLevel::Trace),
        _ => std::result::Result::Err(effective_field_error(profile, field, "effective Logging level is unsupported")),
    };
}

fn map_span_events(value: &str, profile: &crate::ResolvedConfigProfile) -> ksp_core_lib::Result<ksp_logging_lib::SpanEvents> {
    return match value {
        "off" => std::result::Result::Ok(ksp_logging_lib::SpanEvents::Off),
        "new_and_close" => std::result::Result::Ok(ksp_logging_lib::SpanEvents::NewAndClose),
        "full" => std::result::Result::Ok(ksp_logging_lib::SpanEvents::Full),
        _ => std::result::Result::Err(effective_field_error(profile, "span_events", "effective Logging span_events value is unsupported")),
    };
}

fn map_format(value: &str, field: &'static str, profile: &crate::ResolvedConfigProfile) -> ksp_core_lib::Result<ksp_logging_lib::LogFormat> {
    return match value {
        "human" => std::result::Result::Ok(ksp_logging_lib::LogFormat::Human),
        "compact" => std::result::Result::Ok(ksp_logging_lib::LogFormat::Compact),
        "pretty" => std::result::Result::Ok(ksp_logging_lib::LogFormat::Pretty),
        "json" => std::result::Result::Ok(ksp_logging_lib::LogFormat::Json),
        _ => std::result::Result::Err(effective_field_error(profile, field, "effective Logging format is unsupported")),
    };
}

fn map_rotation(value: &str, profile: &crate::ResolvedConfigProfile) -> ksp_core_lib::Result<ksp_logging_lib::FileRotation> {
    return match value {
        "never" => std::result::Result::Ok(ksp_logging_lib::FileRotation::Never),
        "hourly" => std::result::Result::Ok(ksp_logging_lib::FileRotation::Hourly),
        "daily" => std::result::Result::Ok(ksp_logging_lib::FileRotation::Daily),
        _ => std::result::Result::Err(effective_field_error(profile, "files.rotation", "effective Logging rotation is unsupported")),
    };
}

fn resolve_logs_directory(value: &str, safe_value: &str, profile: &crate::ResolvedConfigProfile) -> ksp_core_lib::Result<std::path::PathBuf> {
    if value.trim().is_empty() {
        return std::result::Result::Err(
            effective_field_error(profile, "logs_directory", "effective Logging logs_directory must not be empty").with_context("safe_value", safe_value),
        );
    }
    let configured = std::path::PathBuf::from(value);
    let resolved = if configured.is_absolute() {
        configured
    } else {
        let current_directory = std::env::current_dir();
        let current_directory = match current_directory {
            std::result::Result::Ok(value) => value,
            std::result::Result::Err(error) => {
                return std::result::Result::Err(
                    effective_field_error(profile, "logs_directory", "process current working directory cannot be resolved").with_source(error),
                );
            },
        };
        current_directory.join(configured)
    };
    let metadata = std::fs::metadata(resolved.as_path());
    match metadata {
        std::result::Result::Ok(value) if !value.is_dir() => {
            return std::result::Result::Err(
                effective_field_error(profile, "logs_directory", "effective Logging logs_directory resolves to an existing non-directory path")
                    .with_context("safe_value", safe_value),
            );
        },
        std::result::Result::Ok(_) => {},
        std::result::Result::Err(error) if error.kind() == std::io::ErrorKind::NotFound => {},
        std::result::Result::Err(error) => {
            return std::result::Result::Err(
                effective_field_error(profile, "logs_directory", "effective Logging logs_directory cannot be inspected")
                    .with_context("safe_value", safe_value)
                    .with_source(error),
            );
        },
    }
    return std::result::Result::Ok(resolved);
}

fn relative_file_path_is_valid(value: &str) -> bool {
    let path = std::path::Path::new(value);
    if path.is_absolute() {
        return false;
    }
    let mut has_normal_component = false;
    for component in path.components() {
        match component {
            std::path::Component::Normal(_) => has_normal_component = true,
            std::path::Component::CurDir | std::path::Component::ParentDir | std::path::Component::RootDir | std::path::Component::Prefix(_) => return false,
        }
    }
    return has_normal_component;
}

fn safe_string_at(value: &serde_json::Value, pointer: &str) -> String {
    return match value.pointer(pointer).and_then(serde_json::Value::as_str) {
        std::option::Option::Some(value) => value.to_owned(),
        std::option::Option::None => "<unavailable>".to_owned(),
    };
}

fn effective_field_error(profile: &crate::ResolvedConfigProfile, field: &'static str, reason: &'static str) -> ksp_core_lib::Error {
    return effective_error(profile, reason).with_context("field", field);
}

fn effective_error(profile: &crate::ResolvedConfigProfile, reason: &'static str) -> ksp_core_lib::Error {
    return ksp_core_lib::Error::new(crate::ERROR_CODE_EFFECTIVE_CONFIG_INVALID, "effective Config cannot be mapped to the requested runtime contract")
        .with_context("file_id", profile.file_id().as_str())
        .with_context("profile_id", profile.profile_id())
        .with_context("reason", reason);
}

#[cfg(test)]
#[path = "../unit_tests/logging.rs"]
mod tests;