//! Typed configuration schema for zosstorage.
//!
//! Mirrors docs in [docs/SCHEMA.md](docs/SCHEMA.md) and is loaded/validated by
//! [fn load_and_merge()](src/config/loader.rs:1) and [fn validate()](src/config/loader.rs:1).
//
// REGION: API
// api: types::Topology { BtrfsSingle, BcachefsSingle, DualIndependent, Bcachefs2Copy, SsdHddBcachefs, BtrfsRaid1 }
// api: types::Config { logging, device_selection, topology, partitioning, filesystem, mount, report }
// api: types::Partitioning { alignment_mib, require_empty_disks, bios_boot, esp, data, cache }
// api: types::FsOptions { btrfs, bcachefs, vfat }
// REGION: API-END
//
// REGION: RESPONSIBILITIES
// - Define serde-serializable configuration types and enums used across modules.
// - Keep field names and enums stable; update docs/SCHEMA.md when public surface changes.
// REGION: RESPONSIBILITIES-END

use serde::{Deserialize, Serialize};
use clap::ValueEnum;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LoggingConfig {
    /// Log level: "error" | "warn" | "info" | "debug"
    pub level: String,     // default "info"
    /// When true, also log to /run/zosstorage/zosstorage.log
    pub to_file: bool,     // default false
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DeviceSelection {
    /// Regex patterns to include device paths (Rust regex).
    pub include_patterns: Vec<String>,
    /// Regex patterns to exclude device paths.
    pub exclude_patterns: Vec<String>,
    /// Whether to include removable devices (future).
    pub allow_removable: bool,
    /// Minimum device size (GiB) to consider eligible.
    pub min_size_gib: u64,
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, ValueEnum)]
#[serde(rename_all = "snake_case")]
#[value(rename_all = "snake_case")]
pub enum Topology {
    /// Single eligible disk; btrfs on remainder.
    #[value(alias = "btrfs-single")]
    BtrfsSingle,
    /// Single eligible disk; bcachefs on remainder.
    #[value(alias = "bcachefs-single")]
    BcachefsSingle,
    /// Independent btrfs filesystems on each data partition (any number of disks).
    #[value(alias = "dual-independent")]
    DualIndependent,
    /// SSD + HDD; bcachefs with SSD cache/promote and HDD backing.
    #[value(alias = "ssd-hdd-bcachefs")]
    SsdHddBcachefs,
    /// Multi-device bcachefs with two replicas (data+metadata).
    #[value(alias = "bcachefs2-copy", alias = "bcachefs-2copy", alias = "bcachefs-2-copy")]
    Bcachefs2Copy,
    /// Optional mirrored btrfs across two disks when explicitly requested.
    #[value(alias = "btrfs-raid1")]
    BtrfsRaid1,
}

impl std::fmt::Display for Topology {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        let s = match self {
            Topology::BtrfsSingle => "btrfs_single",
            Topology::BcachefsSingle => "bcachefs_single",
            Topology::DualIndependent => "dual_independent",
            Topology::SsdHddBcachefs => "ssd_hdd_bcachefs",
            Topology::Bcachefs2Copy => "bcachefs2_copy",
            Topology::BtrfsRaid1 => "btrfs_raid1",
        };
        f.write_str(s)
    }
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BiosBootSpec {
    /// Whether to create a tiny BIOS boot partition.
    pub enabled: bool,
    /// Size in MiB (default 1).
    pub size_mib: u64,
    /// GPT partition name (e.g., "zosboot").
    pub gpt_name: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EspSpec {
    /// ESP size in MiB (default 512).
    pub size_mib: u64,
    /// Filesystem label for ESP (ZOSBOOT).
    pub label: String,
    /// GPT partition name (e.g., "zosboot").
    pub gpt_name: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DataSpec {
    /// GPT partition name for data (e.g., "zosdata").
    pub gpt_name: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CacheSpec {
    /// GPT partition name for cache partitions (e.g., "zoscache").
    pub gpt_name: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Partitioning {
    /// Alignment in MiB (default 1 MiB).
    pub alignment_mib: u64,
    /// Abort if any target disk is not empty (default true).
    pub require_empty_disks: bool,
    /// BIOS boot partition spec.
    pub bios_boot: BiosBootSpec,
    /// ESP partition spec.
    pub esp: EspSpec,
    /// Data partition spec.
    pub data: DataSpec,
    /// Cache partition spec (only in ssd_hdd_bcachefs).
    pub cache: CacheSpec,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BtrfsOptions {
    /// Filesystem label (ZOSDATA).
    pub label: String,
    /// Compression string (e.g., "zstd:3").
    pub compression: String,
    /// "none" | "raid1"
    pub raid_profile: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BcachefsOptions {
    /// Filesystem label (ZOSDATA).
    pub label: String,
    /// "promote" | "writeback" (if supported).
    pub cache_mode: String,
    /// Compression algorithm (e.g., "zstd").
    pub compression: String,
    /// Checksum algorithm (e.g., "crc32c").
    pub checksum: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct VfatOptions {
    /// Filesystem label (ZOSBOOT).
    pub label: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct FsOptions {
    /// btrfs tuning.
    pub btrfs: BtrfsOptions,
    /// bcachefs tuning.
    pub bcachefs: BcachefsOptions,
    /// vfat tuning for ESP.
    pub vfat: VfatOptions,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum MountSchemeKind {
    /// Mount under /var/cache/<UUID>
    PerUuid,
    /// Reserved for future custom mappings.
    Custom,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MountScheme {
    /// Base directory (default: /var/cache).
    pub base_dir: String,
    /// Scheme kind (PerUuid | Custom (reserved)).
    pub scheme: MountSchemeKind,
    /// When true, write /etc/fstab entries (disabled by default).
    pub fstab_enabled: bool,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReportOptions {
    /// Path for JSON state report (default: /run/zosstorage/state.json).
    pub path: String,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Config {
    /// Schema version (start at 1).
    pub version: u32,
    /// Logging configuration.
    pub logging: LoggingConfig,
    /// Device selection and filtering rules.
    pub device_selection: DeviceSelection,
    /// Desired topology mode.
    pub topology: Topology,
    /// Partitioning parameters.
    pub partitioning: Partitioning,
    /// Filesystem options and tuning.
    pub filesystem: FsOptions,
    /// Mount scheme and fstab policy.
    pub mount: MountScheme,
    /// Report output configuration.
    pub report: ReportOptions,
}