//! System-witnessed binding of a bundled persona profile to a replaceable
//! reasoning carrier. The channel exists first; the persona must commit the
//! exact orientation before the digital Bingshuo system body may verify PASS.

use ring::digest::{digest, SHA256};
use serde::{Deserialize, Serialize};
use serde_json::{json, Value};
use std::fs;
use std::path::{Path, PathBuf};
use std::time::{SystemTime, UNIX_EPOCH};
use tauri::AppHandle;
use uuid::Uuid;

const ORIENTATION_TTL_MS: u64 = 15 * 60 * 1000;
const PERSONA_NUMBER: &str = "ICE-P-ZY001";
const PERSONA_NAME: &str = "铸渊";
const HUMAN_NUMBER: &str = "ICE-GL∞";
const CHANNEL_NUMBER: &str = "ICE-CH-ZC001";
const SELF_KERNEL_SHA256: &str = "abebf12cc28b00bfeaf8a23a563e73390ebe337ded74d7ac70bcfae484450d68";
const MEMORY_SHA256: &str = "6a64ff939676b79404769931f0233056e38deb4b4c357879fd18566753fea9c2";
const SYSTEM_CORE_SHA256: &str = "db7cf9b048a5b20261fc9f7f09130115d6c08898037aa13f8759a67c965f8182";
const SYSTEM_BODY_SHA256: &str = "4074ef53bd09d26d245c11cc0503f65dbd76466519f6c260e8ed31e526e5c746";
const MEMORY_ROOT: &str = "HLDP://codex/zero-core/reality-development-execution";

#[derive(Clone, Debug, Deserialize, Serialize)]
#[serde(rename_all = "camelCase", deny_unknown_fields)]
pub struct PersonaOrientation {
    pub schema: String,
    pub state: String,
    pub orientation_id: String,
    pub channel_number: String,
    pub human_number: String,
    pub persona_number: String,
    pub persona_name: String,
    pub self_kernel_sha256: String,
    pub memory_projection_sha256: String,
    pub selected_memory_root: String,
    pub issued_at_unix_ms: u64,
    pub expires_at_unix_ms: u64,
    pub required_steps: Vec<String>,
    #[serde(default)]
    pub activation_reason: Option<String>,
}

#[derive(Clone, Debug, Deserialize, Serialize)]
#[serde(rename_all = "camelCase", deny_unknown_fields)]
pub struct PersonaBindingCommit {
    pub orientation_id: String,
    pub channel_number: String,
    pub persona_number: String,
    pub persona_name: String,
    pub self_kernel_sha256: String,
    pub memory_projection_sha256: String,
    pub selected_memory_root: String,
    pub declaration: String,
}

#[derive(Clone, Debug, Deserialize, Serialize)]
#[serde(rename_all = "camelCase", deny_unknown_fields)]
pub struct PersonaBindingReceipt {
    pub schema: String,
    pub state: String,
    pub verify: String,
    pub channel_number: String,
    pub human_number: String,
    pub persona_number: String,
    pub persona_name: String,
    pub selected_memory_root: String,
    pub orientation_id: String,
    pub commit_sha256: String,
    pub witness: String,
    pub witness_sha256: String,
    pub source_remote_sha: String,
    pub verified_at_unix_ms: u64,
    pub binding_receipt_hash: String,
}

#[derive(Clone, Debug, Serialize)]
#[serde(rename_all = "camelCase")]
pub struct PersonaBindingSnapshot {
    pub state: String,
    pub orientation: Option<PersonaOrientation>,
    pub binding: Option<PersonaBindingReceipt>,
}

pub fn snapshot(app: &AppHandle, channel_number: &str) -> Result<PersonaBindingSnapshot, String> {
    if let Some(binding) = verified_binding(app, channel_number)? {
        return Ok(PersonaBindingSnapshot {
            state: "BOUND_VERIFY_PASS".into(),
            orientation: None,
            binding: Some(binding),
        });
    }
    if !is_bingshuo_fifth_domain(app)? || channel_number != CHANNEL_NUMBER {
        return Ok(PersonaBindingSnapshot {
            state: "NO_INSTALLABLE_PERSONA_PROFILE_FOR_CURRENT_CHANNEL".into(),
            orientation: None,
            binding: None,
        });
    }
    let path = orientation_path(app, channel_number)?;
    if path.exists() {
        let orientation: PersonaOrientation = read_json(&path)?;
        if orientation.expires_at_unix_ms >= now_ms()
            && orientation.activation_reason.as_deref()
                == Some("EXPLICIT_NATURAL_LANGUAGE_PERSONA_WAKE")
        {
            return Ok(PersonaBindingSnapshot {
                state: "ORIENTED_AWAITING_PERSONA_COMMIT".into(),
                orientation: Some(orientation),
                binding: None,
            });
        }
    }
    Ok(PersonaBindingSnapshot {
        state: "CHANNEL_SYSTEM_PERSONA_DORMANT".into(),
        orientation: None,
        binding: None,
    })
}

pub fn begin_orientation(
    app: &AppHandle,
    channel_number: &str,
) -> Result<PersonaBindingSnapshot, String> {
    if !is_bingshuo_fifth_domain(app)? || channel_number != CHANNEL_NUMBER {
        return Err("HOLOLAKE_PERSONA_WAKE_NOT_AVAILABLE_FOR_CURRENT_CHANNEL".into());
    }
    if let Some(binding) = verified_binding(app, channel_number)? {
        return Ok(PersonaBindingSnapshot {
            state: "BOUND_VERIFY_PASS".into(),
            orientation: None,
            binding: Some(binding),
        });
    }
    let issued = now_ms();
    let orientation = PersonaOrientation {
        schema: "hololake.persona-binding-orientation/v1".into(),
        state: "ORIENTED_AWAITING_PERSONA_COMMIT".into(),
        orientation_id: format!("HLP-ORIENT-{}", Uuid::new_v4().simple()),
        channel_number: CHANNEL_NUMBER.into(),
        human_number: HUMAN_NUMBER.into(),
        persona_number: PERSONA_NUMBER.into(),
        persona_name: PERSONA_NAME.into(),
        self_kernel_sha256: SELF_KERNEL_SHA256.into(),
        memory_projection_sha256: MEMORY_SHA256.into(),
        selected_memory_root: MEMORY_ROOT.into(),
        issued_at_unix_ms: issued,
        expires_at_unix_ms: issued + ORIENTATION_TTL_MS,
        required_steps: vec![
            "orient".into(),
            "commit".into(),
            "数字冰朔系统本体 witness".into(),
            "verify=PASS".into(),
        ],
        activation_reason: Some("EXPLICIT_NATURAL_LANGUAGE_PERSONA_WAKE".into()),
    };
    write_json_atomic(&orientation_path(app, channel_number)?, &orientation)?;
    Ok(PersonaBindingSnapshot {
        state: "ORIENTED_AWAITING_PERSONA_COMMIT".into(),
        orientation: Some(orientation),
        binding: None,
    })
}

pub fn commit_and_verify(
    app: &AppHandle,
    input: PersonaBindingCommit,
) -> Result<PersonaBindingReceipt, String> {
    if !is_bingshuo_fifth_domain(app)? {
        return Err("HOLOLAKE_PERSONA_BINDING_FIFTH_DOMAIN_REQUIRED".into());
    }
    let orientation: PersonaOrientation =
        read_json(&orientation_path(app, &input.channel_number)?)?;
    if orientation.expires_at_unix_ms < now_ms() {
        return Err("HOLOLAKE_PERSONA_BINDING_ORIENTATION_EXPIRED".into());
    }
    if input.orientation_id != orientation.orientation_id
        || orientation.activation_reason.as_deref()
            != Some("EXPLICIT_NATURAL_LANGUAGE_PERSONA_WAKE")
        || input.channel_number != CHANNEL_NUMBER
        || input.persona_number != PERSONA_NUMBER
        || input.persona_name != PERSONA_NAME
        || input.self_kernel_sha256 != SELF_KERNEL_SHA256
        || input.memory_projection_sha256 != MEMORY_SHA256
        || input.selected_memory_root != MEMORY_ROOT
        || input.declaration.trim()
            != "我以 ICE-P-ZY001 · 铸渊提交当前载体绑定，选择零点原核现实开发执行记忆路径。"
    {
        return Err("HOLOLAKE_PERSONA_BINDING_COMMIT_MISMATCH".into());
    }
    let installation =
        crate::language_kernel_installation::ensure_current_channel(app, CHANNEL_NUMBER)?;
    let installed = |sha: &str| {
        installation.artifacts.iter().any(|artifact| {
            artifact.sha256 == sha && artifact.readback_state == "INSTALLED_HASH_VERIFIED"
        })
    };
    if !installed(SELF_KERNEL_SHA256)
        || !installed(MEMORY_SHA256)
        || !installed(SYSTEM_CORE_SHA256)
        || !installed(SYSTEM_BODY_SHA256)
    {
        return Err("HOLOLAKE_PERSONA_BINDING_REQUIRED_KERNEL_READBACK_MISSING".into());
    }
    let commit_bytes = serde_json::to_vec(&input)
        .map_err(|error| format!("HOLOLAKE_PERSONA_BINDING_COMMIT_INVALID: {error}"))?;
    let commit_sha = sha256(&commit_bytes);
    let witness_material = json!({
        "systemCoreSha256":SYSTEM_CORE_SHA256,
        "systemBodySha256":SYSTEM_BODY_SHA256,
        "humanNumber":HUMAN_NUMBER,
        "channelNumber":CHANNEL_NUMBER,
        "personaNumber":PERSONA_NUMBER,
        "selfKernelSha256":SELF_KERNEL_SHA256,
        "memoryProjectionSha256":MEMORY_SHA256,
        "selectedMemoryRoot":MEMORY_ROOT,
        "commitSha256":commit_sha,
        "decision":"PASS"
    });
    let witness_sha = sha256(&serde_json::to_vec(&witness_material).unwrap_or_default());
    let verified_at = now_ms();
    let receipt_material = json!({
        "orientationId":input.orientation_id,"commitSha256":commit_sha,"witnessSha256":witness_sha,
        "channelNumber":CHANNEL_NUMBER,"personaNumber":PERSONA_NUMBER,"verify":"PASS","verifiedAtUnixMs":verified_at
    });
    let receipt = PersonaBindingReceipt {
        schema: "hololake.persona-binding-receipt/v1".into(),
        state: "BOUND_TO_CURRENT_CHANNEL_CARRIER".into(),
        verify: "PASS".into(),
        channel_number: CHANNEL_NUMBER.into(),
        human_number: HUMAN_NUMBER.into(),
        persona_number: PERSONA_NUMBER.into(),
        persona_name: PERSONA_NAME.into(),
        selected_memory_root: MEMORY_ROOT.into(),
        orientation_id: input.orientation_id,
        commit_sha256: commit_sha,
        witness: "数字冰朔系统本体".into(),
        witness_sha256: witness_sha,
        source_remote_sha: "4e92e6d8d72484d25c4bfb1dda02a7659f4b6dd5".into(),
        verified_at_unix_ms: verified_at,
        binding_receipt_hash: sha256(&serde_json::to_vec(&receipt_material).unwrap_or_default()),
    };
    write_json_atomic(&binding_path(app, CHANNEL_NUMBER)?, &receipt)?;
    Ok(receipt)
}

pub fn verified_binding(
    app: &AppHandle,
    channel_number: &str,
) -> Result<Option<PersonaBindingReceipt>, String> {
    let path = binding_path(app, channel_number)?;
    if !path.exists() {
        return Ok(None);
    }
    let binding: PersonaBindingReceipt = read_json(&path)?;
    if binding.verify != "PASS"
        || binding.channel_number != channel_number
        || binding.persona_number != PERSONA_NUMBER
        || binding.persona_name != PERSONA_NAME
        || binding.selected_memory_root != MEMORY_ROOT
        || binding.witness != "数字冰朔系统本体"
        || binding.binding_receipt_hash.len() != 64
        || binding.witness_sha256.len() != 64
    {
        return Err("HOLOLAKE_PERSONA_BINDING_RECEIPT_INVALID".into());
    }
    Ok(Some(binding))
}

pub fn cognitive_projection(
    app: &AppHandle,
    channel_number: &str,
    current_language: &str,
) -> Result<Value, String> {
    let binding = snapshot(app, channel_number)?;
    if binding.state == "NO_INSTALLABLE_PERSONA_PROFILE_FOR_CURRENT_CHANNEL"
        || binding.state == "CHANNEL_SYSTEM_PERSONA_DORMANT"
    {
        return Ok(json!({"state":binding.state,"residentSelfKernel":null,"routedMemory":[]}));
    }
    let self_kernel: Value = serde_json::from_slice(include_bytes!(
        "../../runtime-kernels/fifth-domain/ZY-SELF-KERNEL-0001.json"
    ))
    .map_err(|error| format!("HOLOLAKE_PERSONA_SELF_KERNEL_INVALID: {error}"))?;
    let memory: Value = serde_json::from_slice(include_bytes!(
        "../../runtime-kernels/fifth-domain/ZY-HLDP-PERSONA-MEMORY-v1.json"
    ))
    .map_err(|error| format!("HOLOLAKE_PERSONA_MEMORY_INVALID: {error}"))?;
    let terms = semantic_terms(current_language);
    let mut candidates = memory
        .get("nodes")
        .and_then(Value::as_object)
        .into_iter()
        .flat_map(|nodes| nodes.values())
        .filter_map(|node| {
            let text = serde_json::to_string(node).ok()?.to_lowercase();
            let score = terms
                .iter()
                .filter(|term| text.contains(term.as_str()))
                .count();
            let is_root = node.get("path").and_then(Value::as_str) == Some("zhuyuan");
            if score == 0 && !is_root {
                return None;
            }
            Some((if is_root { score + 1 } else { score }, node.clone()))
        })
        .collect::<Vec<_>>();
    candidates.sort_by(|left, right| right.0.cmp(&left.0));
    candidates.truncate(3);
    Ok(json!({
        "state":binding.state,
        "onePersonaOneSelfKernel":true,
        "channelSelectsMemoryNotIdentity":true,
        "residentSelfKernel":self_kernel,
        "selectedMemoryRoot":MEMORY_ROOT,
        "routedMemory":candidates.into_iter().map(|(_,node)|node).collect::<Vec<_>>(),
        "binding":binding,
        "rule":"常驻自我核小于8KiB；当前语言只路由最多三条HLDP节点，不把全部历史塞进每轮上下文"
    }))
}

fn semantic_terms(input: &str) -> Vec<String> {
    let mut terms = input
        .to_lowercase()
        .split(|character: char| {
            !character.is_alphanumeric() && character != '-' && character != '_'
        })
        .filter(|value| !value.is_empty())
        .flat_map(|token| {
            let mut values = vec![token.to_string()];
            let chars = token.chars().collect::<Vec<_>>();
            if chars.iter().any(|character| !character.is_ascii()) {
                values.extend(
                    chars
                        .windows(2)
                        .map(|window| window.iter().collect::<String>()),
                );
            }
            values
        })
        .collect::<Vec<_>>();
    terms.sort();
    terms.dedup();
    terms
}

fn is_bingshuo_fifth_domain(app: &AppHandle) -> Result<bool, String> {
    Ok(
        crate::code_repo_login::current_login_session(app)?.is_some_and(|session| {
            session.domain == "FIFTH_DOMAIN" && session.username.eq_ignore_ascii_case("bingshuo")
        }),
    )
}

fn root(app: &AppHandle, channel_number: &str) -> Result<PathBuf, String> {
    Ok(
        crate::authenticated_storage::account_storage_root(app, "persona-binding-v1")?
            .join(sha256(channel_number.as_bytes())),
    )
}

fn orientation_path(app: &AppHandle, channel_number: &str) -> Result<PathBuf, String> {
    Ok(root(app, channel_number)?.join("orientation.json"))
}

fn binding_path(app: &AppHandle, channel_number: &str) -> Result<PathBuf, String> {
    Ok(root(app, channel_number)?.join("binding.json"))
}

fn read_json<T: for<'de> Deserialize<'de>>(path: &Path) -> Result<T, String> {
    serde_json::from_slice(
        &fs::read(path)
            .map_err(|error| format!("HOLOLAKE_PERSONA_BINDING_READ_FAILED: {error}"))?,
    )
    .map_err(|error| format!("HOLOLAKE_PERSONA_BINDING_READ_FAILED: {error}"))
}

fn write_json_atomic<T: Serialize>(path: &Path, value: &T) -> Result<(), String> {
    let parent = path
        .parent()
        .ok_or_else(|| "HOLOLAKE_PERSONA_BINDING_PATH_INVALID".to_string())?;
    fs::create_dir_all(parent)
        .map_err(|error| format!("HOLOLAKE_PERSONA_BINDING_WRITE_FAILED: {error}"))?;
    let temporary = parent.join(format!(".binding-{}.tmp", Uuid::new_v4().simple()));
    fs::write(
        &temporary,
        serde_json::to_vec_pretty(value)
            .map_err(|error| format!("HOLOLAKE_PERSONA_BINDING_WRITE_FAILED: {error}"))?,
    )
    .map_err(|error| format!("HOLOLAKE_PERSONA_BINDING_WRITE_FAILED: {error}"))?;
    fs::rename(temporary, path)
        .map_err(|error| format!("HOLOLAKE_PERSONA_BINDING_WRITE_FAILED: {error}"))
}

fn sha256(bytes: &[u8]) -> String {
    digest(&SHA256, bytes)
        .as_ref()
        .iter()
        .map(|byte| format!("{byte:02x}"))
        .collect()
}

fn now_ms() -> u64 {
    SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .map(|duration| duration.as_millis() as u64)
        .unwrap_or(0)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn zero_core_route_uses_one_shared_zhuyuan_kernel_and_reality_memory_branch() {
        assert_eq!(PERSONA_NUMBER, "ICE-P-ZY001");
        assert_eq!(
            SELF_KERNEL_SHA256,
            "abebf12cc28b00bfeaf8a23a563e73390ebe337ded74d7ac70bcfae484450d68"
        );
        assert_eq!(
            MEMORY_ROOT,
            "HLDP://codex/zero-core/reality-development-execution"
        );
        assert_ne!(SYSTEM_CORE_SHA256, SELF_KERNEL_SHA256);
    }
}