use aether_contracts::{ExecutionError, ExecutionPlan};
use aether_data_contracts::repository::candidates::{
    RequestCandidateStatus, StoredRequestCandidate, UpsertRequestCandidateRecord,
};
use serde_json::{Map, Value};

#[derive(Debug, Clone, PartialEq)]
pub struct SchedulerRequestCandidateReportContext {
    pub request_id: Option<String>,
    pub candidate_id: Option<String>,
    pub user_id: Option<String>,
    pub api_key_id: Option<String>,
    pub candidate_index: Option<u32>,
    pub retry_index: u32,
    pub provider_id: Option<String>,
    pub endpoint_id: Option<String>,
    pub key_id: Option<String>,
    pub client_api_format: Option<String>,
    pub provider_api_format: Option<String>,
    pub upstream_url: Option<String>,
    pub mapped_model: Option<String>,
    pub key_name: Option<String>,
    pub header_rules: Option<Value>,
    pub body_rules: Option<Value>,
    pub proxy: Option<Value>,
    pub error_flow: Option<Value>,
    pub ranking_mode: Option<String>,
    pub priority_mode: Option<String>,
    pub ranking_index: Option<u32>,
    pub priority_slot: Option<i32>,
    pub promoted_by: Option<String>,
    pub demoted_by: Option<String>,
}

#[derive(Debug, Clone, PartialEq)]
pub struct SchedulerResolvedReportRequestCandidateSlot {
    pub id: String,
    pub request_id: String,
    pub user_id: Option<String>,
    pub api_key_id: Option<String>,
    pub candidate_index: u32,
    pub retry_index: u32,
    pub provider_id: Option<String>,
    pub endpoint_id: Option<String>,
    pub key_id: Option<String>,
    pub extra_data: Option<Value>,
    pub created_at_unix_ms: u64,
    pub started_at_unix_ms: Option<u64>,
    pub finished_at_unix_ms: Option<u64>,
}

pub struct SchedulerExecutionRequestCandidateSeed {
    pub upsert_record: UpsertRequestCandidateRecord,
    pub report_context: Value,
}

#[derive(Debug, Clone, Default)]
struct ReportCandidateExtraDataInput {
    client_api_format: Option<String>,
    provider_api_format: Option<String>,
    upstream_url: Option<String>,
    mapped_model: Option<String>,
    key_name: Option<String>,
    header_rules: Option<Value>,
    body_rules: Option<Value>,
    proxy: Option<Value>,
    error_flow: Option<Value>,
    ranking_mode: Option<String>,
    priority_mode: Option<String>,
    ranking_index: Option<u32>,
    priority_slot: Option<i32>,
    promoted_by: Option<String>,
    demoted_by: Option<String>,
}

#[derive(Debug, Clone, PartialEq, Eq)]
pub struct SchedulerRequestCandidateStatusUpdate {
    pub status: RequestCandidateStatus,
    pub status_code: Option<u16>,
    pub error_type: Option<String>,
    pub error_message: Option<String>,
    pub latency_ms: Option<u64>,
    pub started_at_unix_ms: Option<u64>,
    pub finished_at_unix_ms: Option<u64>,
}

#[derive(Debug, Clone)]
pub struct LocalRequestCandidateStatusRecordInput<'a> {
    pub plan: &'a ExecutionPlan,
    pub report_context: Option<&'a Value>,
    pub status_update: SchedulerRequestCandidateStatusUpdate,
}

#[derive(Debug, Clone)]
pub struct ReportRequestCandidateStatusRecordInput {
    pub slot: SchedulerResolvedReportRequestCandidateSlot,
    pub status_update: SchedulerRequestCandidateStatusUpdate,
    pub now_unix_ms: u64,
}

pub fn execution_error_details(
    error: Option<&ExecutionError>,
    body_json: Option<&Value>,
) -> (Option<String>, Option<String>) {
    match error {
        Some(error) => (
            Some(format!("{:?}", error.kind)),
            Some(error.message.trim().to_string()).filter(|value| !value.is_empty()),
        ),
        None => (
            None,
            body_json
                .and_then(extract_error_message)
                .map(str::trim)
                .filter(|value| !value.is_empty())
                .map(ToOwned::to_owned),
        ),
    }
}

pub fn parse_request_candidate_report_context(
    report_context: Option<&Value>,
) -> Option<SchedulerRequestCandidateReportContext> {
    let report_context = report_context?;
    Some(SchedulerRequestCandidateReportContext {
        request_id: string_field(report_context, "request_id"),
        candidate_id: string_field(report_context, "candidate_id"),
        user_id: string_field(report_context, "user_id"),
        api_key_id: string_field(report_context, "api_key_id"),
        candidate_index: u32_field(report_context, "candidate_index"),
        retry_index: u32_field(report_context, "retry_index").unwrap_or_default(),
        provider_id: string_field(report_context, "provider_id"),
        endpoint_id: string_field(report_context, "endpoint_id"),
        key_id: string_field(report_context, "key_id"),
        client_api_format: string_field(report_context, "client_api_format"),
        provider_api_format: string_field(report_context, "provider_api_format"),
        upstream_url: string_field(report_context, "upstream_url"),
        mapped_model: string_field(report_context, "mapped_model"),
        key_name: string_field(report_context, "key_name"),
        header_rules: report_context
            .get("header_rules")
            .cloned()
            .filter(|value| !value.is_null()),
        body_rules: report_context
            .get("body_rules")
            .cloned()
            .filter(|value| !value.is_null()),
        proxy: report_context
            .get("proxy")
            .cloned()
            .filter(|value| !value.is_null()),
        error_flow: report_context
            .get("error_flow")
            .cloned()
            .filter(|value| !value.is_null()),
        ranking_mode: string_field(report_context, "ranking_mode"),
        priority_mode: string_field(report_context, "priority_mode"),
        ranking_index: u32_field(report_context, "ranking_index"),
        priority_slot: i32_field(report_context, "priority_slot"),
        promoted_by: string_field(report_context, "promoted_by"),
        demoted_by: string_field(report_context, "demoted_by"),
    })
}

pub fn resolve_report_request_candidate_slot(
    existing_candidates: &[StoredRequestCandidate],
    metadata: SchedulerRequestCandidateReportContext,
    now_unix_ms: u64,
    generated_candidate_id: String,
) -> Option<SchedulerResolvedReportRequestCandidateSlot> {
    let matched_candidate = match_existing_report_candidate(existing_candidates, &metadata);
    let SchedulerRequestCandidateReportContext {
        request_id,
        candidate_id,
        user_id,
        api_key_id,
        candidate_index: metadata_candidate_index,
        retry_index,
        provider_id,
        endpoint_id,
        key_id,
        client_api_format,
        provider_api_format,
        upstream_url,
        mapped_model,
        key_name,
        header_rules,
        body_rules,
        proxy,
        error_flow,
        ranking_mode,
        priority_mode,
        ranking_index,
        priority_slot,
        promoted_by,
        demoted_by,
    } = metadata;
    let request_id = request_id?;
    let synthesized_extra_data = build_report_candidate_extra_data(ReportCandidateExtraDataInput {
        client_api_format,
        provider_api_format,
        upstream_url,
        mapped_model,
        key_name,
        header_rules,
        body_rules,
        proxy,
        error_flow,
        ranking_mode,
        priority_mode,
        ranking_index,
        priority_slot,
        promoted_by,
        demoted_by,
    });
    let created_at_unix_ms = matched_candidate
        .as_ref()
        .map(|candidate| candidate.created_at_unix_ms)
        .unwrap_or(now_unix_ms);
    let candidate_index = matched_candidate
        .as_ref()
        .map(|candidate| candidate.candidate_index)
        .or(metadata_candidate_index)
        .unwrap_or_else(|| next_candidate_index(existing_candidates));
    let retry_index = matched_candidate
        .as_ref()
        .map(|candidate| candidate.retry_index)
        .unwrap_or(retry_index);

    Some(SchedulerResolvedReportRequestCandidateSlot {
        id: matched_candidate
            .as_ref()
            .map(|candidate| candidate.id.clone())
            .or(candidate_id)
            .unwrap_or(generated_candidate_id),
        request_id,
        user_id: matched_candidate
            .as_ref()
            .and_then(|candidate| candidate.user_id.clone())
            .or(user_id),
        api_key_id: matched_candidate
            .as_ref()
            .and_then(|candidate| candidate.api_key_id.clone())
            .or(api_key_id),
        candidate_index,
        retry_index,
        provider_id: matched_candidate
            .as_ref()
            .and_then(|candidate| candidate.provider_id.clone())
            .or(provider_id),
        endpoint_id: matched_candidate
            .as_ref()
            .and_then(|candidate| candidate.endpoint_id.clone())
            .or(endpoint_id),
        key_id: matched_candidate
            .as_ref()
            .and_then(|candidate| candidate.key_id.clone())
            .or(key_id),
        extra_data: merge_request_candidate_extra_data(
            matched_candidate
                .as_ref()
                .and_then(|candidate| candidate.extra_data.clone()),
            synthesized_extra_data,
        ),
        created_at_unix_ms,
        started_at_unix_ms: matched_candidate
            .as_ref()
            .and_then(|candidate| candidate.started_at_unix_ms),
        finished_at_unix_ms: matched_candidate
            .as_ref()
            .and_then(|candidate| candidate.finished_at_unix_ms),
    })
}

pub fn build_execution_request_candidate_seed(
    plan: &ExecutionPlan,
    report_context: Option<&Value>,
    started_at_unix_ms: u64,
    generated_candidate_id: String,
) -> SchedulerExecutionRequestCandidateSeed {
    let mut context = report_context
        .and_then(Value::as_object)
        .cloned()
        .unwrap_or_default();
    let request_id =
        string_field_from_object(&context, "request_id").unwrap_or_else(|| plan.request_id.clone());
    let candidate_index = u32_field_from_object(&context, "candidate_index").unwrap_or(0);
    let retry_index = u32_field_from_object(&context, "retry_index").unwrap_or(0);
    let candidate_id =
        string_field_from_object(&context, "candidate_id").unwrap_or(generated_candidate_id);
    let user_id = string_field_from_object(&context, "user_id");
    let api_key_id = string_field_from_object(&context, "api_key_id");

    context.insert("request_id".to_string(), Value::String(request_id.clone()));
    context.insert(
        "candidate_id".to_string(),
        Value::String(candidate_id.clone()),
    );
    context.insert(
        "candidate_index".to_string(),
        Value::Number(candidate_index.into()),
    );
    context.insert(
        "provider_id".to_string(),
        Value::String(plan.provider_id.clone()),
    );
    context.insert(
        "endpoint_id".to_string(),
        Value::String(plan.endpoint_id.clone()),
    );
    context.insert("key_id".to_string(), Value::String(plan.key_id.clone()));
    let mut extra_data = parse_request_candidate_report_context(Some(&Value::Object(
        context.clone(),
    )))
    .and_then(|metadata| {
        build_report_candidate_extra_data(ReportCandidateExtraDataInput {
            client_api_format: metadata.client_api_format,
            provider_api_format: metadata.provider_api_format,
            upstream_url: metadata.upstream_url,
            mapped_model: metadata.mapped_model,
            key_name: metadata.key_name,
            header_rules: metadata.header_rules,
            body_rules: metadata.body_rules,
            proxy: metadata.proxy,
            error_flow: metadata.error_flow,
            ranking_mode: metadata.ranking_mode,
            priority_mode: metadata.priority_mode,
            ranking_index: metadata.ranking_index,
            priority_slot: metadata.priority_slot,
            promoted_by: metadata.promoted_by,
            demoted_by: metadata.demoted_by,
        })
    });
    append_seed_extra_data_from_report_context(&mut extra_data, &context);

    SchedulerExecutionRequestCandidateSeed {
        upsert_record: UpsertRequestCandidateRecord {
            id: candidate_id,
            request_id,
            user_id,
            api_key_id,
            username: None,
            api_key_name: None,
            candidate_index,
            retry_index,
            provider_id: Some(plan.provider_id.clone()),
            endpoint_id: Some(plan.endpoint_id.clone()),
            key_id: Some(plan.key_id.clone()),
            status: RequestCandidateStatus::Pending,
            skip_reason: None,
            is_cached: Some(false),
            status_code: None,
            error_type: None,
            error_message: None,
            latency_ms: None,
            concurrent_requests: None,
            extra_data,
            required_capabilities: None,
            created_at_unix_ms: Some(started_at_unix_ms),
            started_at_unix_ms: Some(started_at_unix_ms),
            finished_at_unix_ms: None,
        },
        report_context: Value::Object(context),
    }
}

fn append_seed_extra_data_from_report_context(
    extra_data: &mut Option<Value>,
    context: &Map<String, Value>,
) {
    const PASSTHROUGH_FIELDS: &[&str] = &[
        "execution_strategy",
        "conversion_mode",
        "client_contract",
        "provider_contract",
        "transport_diagnostics",
    ];

    let mut object = extra_data
        .take()
        .and_then(|value| match value {
            Value::Object(object) => Some(object),
            _ => None,
        })
        .unwrap_or_default();
    for field in PASSTHROUGH_FIELDS {
        if let Some(value) = context.get(*field).filter(|value| !value.is_null()) {
            object.insert((*field).to_string(), value.clone());
        }
    }
    *extra_data = (!object.is_empty()).then_some(Value::Object(object));
}

pub fn build_local_request_candidate_status_record(
    input: LocalRequestCandidateStatusRecordInput<'_>,
) -> Option<UpsertRequestCandidateRecord> {
    let LocalRequestCandidateStatusRecordInput {
        plan,
        report_context,
        status_update,
    } = input;
    let SchedulerRequestCandidateStatusUpdate {
        status,
        status_code,
        error_type,
        error_message,
        latency_ms,
        started_at_unix_ms,
        finished_at_unix_ms,
    } = status_update;

    let candidate_id = plan
        .candidate_id
        .as_deref()
        .map(str::trim)
        .filter(|value| !value.is_empty())?;
    let metadata = parse_request_candidate_report_context(report_context)?;
    let candidate_index = metadata.candidate_index?;
    let extra_data = build_report_candidate_extra_data(ReportCandidateExtraDataInput {
        client_api_format: metadata.client_api_format.clone(),
        provider_api_format: metadata.provider_api_format.clone(),
        upstream_url: metadata.upstream_url.clone(),
        mapped_model: metadata.mapped_model.clone(),
        key_name: metadata.key_name.clone(),
        header_rules: metadata.header_rules.clone(),
        body_rules: metadata.body_rules.clone(),
        proxy: metadata.proxy.clone(),
        error_flow: metadata.error_flow.clone(),
        ranking_mode: metadata.ranking_mode.clone(),
        priority_mode: metadata.priority_mode.clone(),
        ranking_index: metadata.ranking_index,
        priority_slot: metadata.priority_slot,
        promoted_by: metadata.promoted_by.clone(),
        demoted_by: metadata.demoted_by.clone(),
    });
    let created_at_unix_ms = started_at_unix_ms.or(finished_at_unix_ms);

    Some(UpsertRequestCandidateRecord {
        id: candidate_id.to_string(),
        request_id: plan.request_id.clone(),
        user_id: metadata.user_id,
        api_key_id: metadata.api_key_id,
        username: None,
        api_key_name: None,
        candidate_index,
        retry_index: metadata.retry_index,
        provider_id: Some(plan.provider_id.clone()),
        endpoint_id: Some(plan.endpoint_id.clone()),
        key_id: Some(plan.key_id.clone()),
        status,
        skip_reason: None,
        is_cached: None,
        status_code,
        error_type,
        error_message,
        latency_ms,
        concurrent_requests: None,
        extra_data,
        required_capabilities: None,
        created_at_unix_ms,
        started_at_unix_ms,
        finished_at_unix_ms,
    })
}

pub fn build_report_request_candidate_status_record(
    input: ReportRequestCandidateStatusRecordInput,
) -> UpsertRequestCandidateRecord {
    let ReportRequestCandidateStatusRecordInput {
        slot,
        status_update,
        now_unix_ms,
    } = input;
    let SchedulerRequestCandidateStatusUpdate {
        status,
        status_code,
        error_type,
        error_message,
        latency_ms,
        started_at_unix_ms,
        finished_at_unix_ms,
    } = status_update;

    let terminal_unix_secs = finished_at_unix_ms.unwrap_or(now_unix_ms);
    let started_at_unix_ms = started_at_unix_ms
        .or(slot.started_at_unix_ms)
        .or_else(|| status.is_attempted(None).then_some(terminal_unix_secs));
    let finished_at_unix_ms = finished_at_unix_ms
        .or(slot.finished_at_unix_ms)
        .or_else(|| is_terminal_candidate_status(status).then_some(terminal_unix_secs));
    let created_at_unix_ms = non_epoch_unix_ms(slot.created_at_unix_ms)
        .or_else(|| started_at_unix_ms.and_then(non_epoch_unix_ms))
        .or_else(|| finished_at_unix_ms.and_then(non_epoch_unix_ms))
        .unwrap_or(terminal_unix_secs);

    UpsertRequestCandidateRecord {
        id: slot.id,
        request_id: slot.request_id,
        user_id: slot.user_id,
        api_key_id: slot.api_key_id,
        username: None,
        api_key_name: None,
        candidate_index: slot.candidate_index,
        retry_index: slot.retry_index,
        provider_id: slot.provider_id,
        endpoint_id: slot.endpoint_id,
        key_id: slot.key_id,
        status,
        skip_reason: None,
        is_cached: None,
        status_code,
        error_type,
        error_message,
        latency_ms,
        concurrent_requests: None,
        extra_data: slot.extra_data,
        required_capabilities: None,
        created_at_unix_ms: Some(created_at_unix_ms),
        started_at_unix_ms,
        finished_at_unix_ms,
    }
}

fn non_epoch_unix_ms(value: u64) -> Option<u64> {
    (value > 1000).then_some(value)
}

pub fn finalize_execution_request_candidate_report_context(
    report_context: Value,
    candidate_id: &str,
) -> Value {
    let mut context = match report_context {
        Value::Object(context) => context,
        _ => Map::new(),
    };
    let candidate_id = candidate_id.trim();
    if !candidate_id.is_empty() {
        context.insert(
            "candidate_id".to_string(),
            Value::String(candidate_id.to_string()),
        );
    }
    Value::Object(context)
}

pub fn is_terminal_candidate_status(status: RequestCandidateStatus) -> bool {
    matches!(
        status,
        RequestCandidateStatus::Unused
            | RequestCandidateStatus::Success
            | RequestCandidateStatus::Failed
            | RequestCandidateStatus::Cancelled
            | RequestCandidateStatus::Skipped
    )
}

fn extract_error_message(body_json: &Value) -> Option<&str> {
    body_json
        .get("error")
        .and_then(|error| {
            error
                .get("message")
                .and_then(Value::as_str)
                .or_else(|| error.as_str())
        })
        .or_else(|| body_json.get("message").and_then(Value::as_str))
}

fn string_field(value: &Value, key: &str) -> Option<String> {
    value
        .as_object()
        .and_then(|object| string_field_from_object(object, key))
}

fn string_field_from_object(object: &Map<String, Value>, key: &str) -> Option<String> {
    object
        .get(key)
        .and_then(Value::as_str)
        .map(str::trim)
        .filter(|value| !value.is_empty())
        .map(ToOwned::to_owned)
}

fn u32_field(value: &Value, key: &str) -> Option<u32> {
    value
        .as_object()
        .and_then(|object| u32_field_from_object(object, key))
}

fn u32_field_from_object(object: &Map<String, Value>, key: &str) -> Option<u32> {
    object
        .get(key)
        .and_then(Value::as_u64)
        .and_then(|value| u32::try_from(value).ok())
}

fn i32_field(value: &Value, key: &str) -> Option<i32> {
    value
        .as_object()
        .and_then(|object| object.get(key))
        .and_then(Value::as_i64)
        .and_then(|value| i32::try_from(value).ok())
}

fn match_existing_report_candidate<'a>(
    candidates: &'a [StoredRequestCandidate],
    metadata: &SchedulerRequestCandidateReportContext,
) -> Option<&'a StoredRequestCandidate> {
    if let Some(candidate_id) = metadata.candidate_id.as_deref() {
        if let Some(candidate) = candidates
            .iter()
            .find(|candidate| candidate.id == candidate_id)
        {
            return Some(candidate);
        }
    }

    if let Some(candidate_index) = metadata.candidate_index {
        if let Some(candidate) = candidates.iter().find(|candidate| {
            candidate.candidate_index == candidate_index
                && candidate.retry_index == metadata.retry_index
        }) {
            return Some(candidate);
        }
    }

    candidates
        .iter()
        .filter(|candidate| {
            candidate.provider_id.as_deref() == metadata.provider_id.as_deref()
                && candidate.endpoint_id.as_deref() == metadata.endpoint_id.as_deref()
                && candidate.key_id.as_deref() == metadata.key_id.as_deref()
        })
        .max_by_key(|candidate| {
            (
                candidate.retry_index,
                candidate.candidate_index,
                candidate.created_at_unix_ms,
            )
        })
}

fn next_candidate_index(candidates: &[StoredRequestCandidate]) -> u32 {
    candidates
        .iter()
        .map(|candidate| candidate.candidate_index)
        .max()
        .map(|value| value.saturating_add(1))
        .unwrap_or_default()
}

fn build_report_candidate_extra_data(input: ReportCandidateExtraDataInput) -> Option<Value> {
    let ReportCandidateExtraDataInput {
        client_api_format,
        provider_api_format,
        upstream_url,
        mapped_model,
        key_name,
        header_rules,
        body_rules,
        proxy,
        error_flow,
        ranking_mode,
        priority_mode,
        ranking_index,
        priority_slot,
        promoted_by,
        demoted_by,
    } = input;
    let mut extra_data = Map::with_capacity(8);
    extra_data.insert("gateway_execution_runtime".to_string(), Value::Bool(true));
    extra_data.insert("phase".to_string(), Value::String("3c_trial".to_string()));
    if let Some(client_api_format) = client_api_format {
        extra_data.insert(
            "client_api_format".to_string(),
            Value::String(client_api_format),
        );
    }
    if let Some(provider_api_format) = provider_api_format {
        extra_data.insert(
            "provider_api_format".to_string(),
            Value::String(provider_api_format),
        );
    }
    if let Some(upstream_url) = upstream_url {
        extra_data.insert("upstream_url".to_string(), Value::String(upstream_url));
    }
    if let Some(mapped_model) = mapped_model {
        extra_data.insert("mapped_model".to_string(), Value::String(mapped_model));
    }
    if let Some(key_name) = key_name {
        extra_data.insert("key_name".to_string(), Value::String(key_name));
    }
    if let Some(header_rules) = header_rules {
        extra_data.insert("header_rules".to_string(), header_rules);
    }
    if let Some(body_rules) = body_rules {
        extra_data.insert("body_rules".to_string(), body_rules);
    }
    if let Some(proxy) = proxy {
        extra_data.insert("proxy".to_string(), proxy);
    }
    if let Some(error_flow) = error_flow {
        extra_data.insert("error_flow".to_string(), error_flow);
    }
    if let Some(ranking_mode) = ranking_mode {
        extra_data.insert("ranking_mode".to_string(), Value::String(ranking_mode));
    }
    if let Some(priority_mode) = priority_mode {
        extra_data.insert("priority_mode".to_string(), Value::String(priority_mode));
    }
    if let Some(ranking_index) = ranking_index {
        extra_data.insert(
            "ranking_index".to_string(),
            Value::Number(ranking_index.into()),
        );
    }
    if let Some(priority_slot) = priority_slot {
        extra_data.insert(
            "priority_slot".to_string(),
            Value::Number(priority_slot.into()),
        );
    }
    if let Some(promoted_by) = promoted_by {
        extra_data.insert("promoted_by".to_string(), Value::String(promoted_by));
    }
    if let Some(demoted_by) = demoted_by {
        extra_data.insert("demoted_by".to_string(), Value::String(demoted_by));
    }
    (!extra_data.is_empty()).then_some(Value::Object(extra_data))
}

fn merge_request_candidate_extra_data(
    existing: Option<Value>,
    overlay: Option<Value>,
) -> Option<Value> {
    match (existing, overlay) {
        (Some(Value::Object(mut existing_object)), Some(Value::Object(overlay_object))) => {
            existing_object.extend(overlay_object);
            Some(Value::Object(existing_object))
        }
        (Some(existing), None) => Some(existing),
        (None, Some(overlay)) => Some(overlay),
        (Some(existing), Some(_overlay)) => Some(existing),
        (None, None) => None,
    }
}

#[cfg(test)]
mod tests {
    use aether_contracts::{
        ExecutionError, ExecutionErrorKind, ExecutionPhase, ExecutionPlan, RequestBody,
    };
    use aether_data_contracts::repository::candidates::{
        RequestCandidateStatus, StoredRequestCandidate,
    };
    use serde_json::{json, Value};

    use super::{
        build_execution_request_candidate_seed, build_local_request_candidate_status_record,
        build_report_request_candidate_status_record, execution_error_details,
        finalize_execution_request_candidate_report_context,
        parse_request_candidate_report_context, resolve_report_request_candidate_slot,
        LocalRequestCandidateStatusRecordInput, ReportRequestCandidateStatusRecordInput,
        SchedulerRequestCandidateStatusUpdate, SchedulerResolvedReportRequestCandidateSlot,
    };

    fn sample_candidate(
        id: &str,
        candidate_index: u32,
        retry_index: u32,
    ) -> StoredRequestCandidate {
        StoredRequestCandidate::new(
            id.to_string(),
            "req-1".to_string(),
            Some("user-1".to_string()),
            Some("key-1".to_string()),
            None,
            None,
            candidate_index as i32,
            retry_index as i32,
            Some("provider-1".to_string()),
            Some("endpoint-1".to_string()),
            Some("catalog-key-1".to_string()),
            RequestCandidateStatus::Pending,
            None,
            false,
            None,
            None,
            None,
            None,
            None,
            None,
            None,
            100_000,
            Some(110_000),
            None,
        )
        .expect("candidate should build")
    }

    fn sample_plan() -> ExecutionPlan {
        ExecutionPlan {
            request_id: "req-1".to_string(),
            candidate_id: None,
            provider_name: Some("openai".to_string()),
            provider_id: "provider-1".to_string(),
            endpoint_id: "endpoint-1".to_string(),
            key_id: "key-1".to_string(),
            method: "POST".to_string(),
            url: "https://example.com/v1/chat/completions".to_string(),
            headers: Default::default(),
            content_type: Some("application/json".to_string()),
            content_encoding: None,
            body: RequestBody::from_json(json!({"model": "gpt-5"})),
            stream: false,
            client_api_format: "openai:chat".to_string(),
            provider_api_format: "openai:chat".to_string(),
            model_name: Some("gpt-5".to_string()),
            proxy: None,
            transport_profile: None,
            timeouts: None,
        }
    }

    #[test]
    fn parses_report_context_and_resolves_existing_candidate_slot() {
        let metadata = parse_request_candidate_report_context(Some(&json!({
            "request_id": "req-1",
            "candidate_index": 1,
            "retry_index": 2,
            "provider_id": "provider-1",
            "endpoint_id": "endpoint-1",
            "key_id": "catalog-key-1",
            "client_api_format": "openai:chat"
        })))
        .expect("metadata");
        let slot = resolve_report_request_candidate_slot(
            &[sample_candidate("cand-1", 1, 2)],
            metadata,
            123,
            "generated-1".to_string(),
        )
        .expect("slot");

        assert_eq!(slot.id, "cand-1");
        assert_eq!(slot.candidate_index, 1);
        assert_eq!(slot.retry_index, 2);
        assert_eq!(slot.request_id, "req-1");
    }

    #[test]
    fn merges_proxy_trace_info_into_existing_candidate_extra_data() {
        let mut existing = sample_candidate("cand-1", 1, 0);
        existing.extra_data = Some(json!({
            "provider_name": "Provider One"
        }));

        let metadata = parse_request_candidate_report_context(Some(&json!({
            "request_id": "req-1",
            "candidate_index": 1,
            "retry_index": 0,
            "provider_id": "provider-1",
            "endpoint_id": "endpoint-1",
            "key_id": "catalog-key-1",
            "client_api_format": "openai:chat",
            "provider_api_format": "openai:responses",
            "header_rules": [
                {"op": "set", "name": "x-test", "value": "1"}
            ],
            "body_rules": [
                {"op": "remove", "path": "/store"}
            ],
            "proxy": {
                "node_id": "proxy-node-1",
                "node_name": "edge-1",
                "source": "provider"
            },
            "error_flow": {
                "classification": "retry_upstream_failure",
                "decision": "retry_next_candidate",
                "propagation": "suppressed"
            }
        })))
        .expect("metadata");

        let slot = resolve_report_request_candidate_slot(
            &[existing],
            metadata,
            123,
            "generated-1".to_string(),
        )
        .expect("slot");

        assert_eq!(
            slot.extra_data
                .as_ref()
                .and_then(|value| value.get("provider_name")),
            Some(&json!("Provider One"))
        );
        assert_eq!(
            slot.extra_data
                .as_ref()
                .and_then(|value| value.get("proxy"))
                .and_then(|value| value.get("node_id")),
            Some(&json!("proxy-node-1"))
        );
        assert_eq!(
            slot.extra_data
                .as_ref()
                .and_then(|value| value.get("proxy"))
                .and_then(|value| value.get("source")),
            Some(&json!("provider"))
        );
        assert_eq!(
            slot.extra_data
                .as_ref()
                .and_then(|value| value.get("header_rules"))
                .and_then(Value::as_array)
                .map(Vec::len),
            Some(1)
        );
        assert_eq!(
            slot.extra_data
                .as_ref()
                .and_then(|value| value.get("body_rules"))
                .and_then(Value::as_array)
                .map(Vec::len),
            Some(1)
        );
        assert_eq!(
            slot.extra_data
                .as_ref()
                .and_then(|value| value.get("error_flow"))
                .and_then(|value| value.get("propagation")),
            Some(&json!("suppressed"))
        );
    }

    #[test]
    fn resolves_error_details_from_execution_error_or_body_json() {
        let error = ExecutionError {
            kind: ExecutionErrorKind::Upstream5xx,
            phase: ExecutionPhase::FirstByte,
            message: " upstream failed ".to_string(),
            upstream_status: Some(502),
            retryable: true,
            failover_recommended: true,
        };
        assert_eq!(
            execution_error_details(Some(&error), None),
            (
                Some("Upstream5xx".to_string()),
                Some("upstream failed".to_string())
            )
        );
        assert_eq!(
            execution_error_details(None, Some(&json!({"error": {"message": "bad request"}}))),
            (None, Some("bad request".to_string()))
        );
    }

    #[test]
    fn builds_execution_request_candidate_seed_and_finalizes_report_context() {
        let seed = build_execution_request_candidate_seed(
            &sample_plan(),
            Some(&json!({
                "request_id": "req-override",
                "candidate_index": 3,
                "retry_index": 2,
                "user_id": "user-1",
                "api_key_id": "api-key-1",
                "client_api_format": "openai:chat"
            })),
            123,
            "generated-1".to_string(),
        );

        assert_eq!(seed.upsert_record.id, "generated-1");
        assert_eq!(seed.upsert_record.request_id, "req-override");
        assert_eq!(seed.upsert_record.candidate_index, 3);
        assert_eq!(seed.upsert_record.retry_index, 2);
        assert_eq!(seed.upsert_record.user_id.as_deref(), Some("user-1"));
        assert_eq!(
            seed.report_context
                .get("provider_id")
                .and_then(Value::as_str),
            Some("provider-1")
        );

        let finalized =
            finalize_execution_request_candidate_report_context(seed.report_context, "cand-final");
        assert_eq!(
            finalized.get("candidate_id").and_then(Value::as_str),
            Some("cand-final")
        );
    }

    #[test]
    fn builds_local_request_candidate_status_record() {
        let mut plan = sample_plan();
        plan.candidate_id = Some("cand-1".to_string());

        let record =
            build_local_request_candidate_status_record(LocalRequestCandidateStatusRecordInput {
                plan: &plan,
                report_context: Some(&json!({
                    "candidate_index": 1,
                    "retry_index": 2,
                    "user_id": "user-1",
                    "api_key_id": "api-key-1",
                    "client_api_format": "openai:chat",
                    "provider_api_format": "openai:responses",
                    "upstream_url": "https://example.com/v1/responses",
                    "mapped_model": "gpt-5-upstream",
                    "key_name": "primary",
                    "ranking_mode": "CacheAffinity",
                    "priority_mode": "Provider",
                    "ranking_index": 2,
                    "priority_slot": 7,
                    "promoted_by": "cached_affinity",
                    "demoted_by": "cross_format"
                })),
                status_update: SchedulerRequestCandidateStatusUpdate {
                    status: RequestCandidateStatus::Failed,
                    status_code: Some(500),
                    error_type: Some("Upstream5xx".to_string()),
                    error_message: Some("boom".to_string()),
                    latency_ms: Some(42),
                    started_at_unix_ms: Some(100),
                    finished_at_unix_ms: Some(101),
                },
            })
            .expect("record should build");

        assert_eq!(record.id, "cand-1");
        assert_eq!(record.candidate_index, 1);
        assert_eq!(record.retry_index, 2);
        assert_eq!(record.user_id.as_deref(), Some("user-1"));
        assert_eq!(record.status, RequestCandidateStatus::Failed);
        assert_eq!(record.created_at_unix_ms, Some(100));
        assert_eq!(
            record
                .extra_data
                .as_ref()
                .and_then(|value| value.get("provider_api_format")),
            Some(&json!("openai:responses"))
        );
        assert_eq!(
            record
                .extra_data
                .as_ref()
                .and_then(|value| value.get("mapped_model")),
            Some(&json!("gpt-5-upstream"))
        );
        assert_eq!(
            record
                .extra_data
                .as_ref()
                .and_then(|value| value.get("ranking_mode")),
            Some(&json!("CacheAffinity"))
        );
        assert_eq!(
            record
                .extra_data
                .as_ref()
                .and_then(|value| value.get("priority_mode")),
            Some(&json!("Provider"))
        );
        assert_eq!(
            record
                .extra_data
                .as_ref()
                .and_then(|value| value.get("ranking_index")),
            Some(&json!(2))
        );
        assert_eq!(
            record
                .extra_data
                .as_ref()
                .and_then(|value| value.get("priority_slot")),
            Some(&json!(7))
        );
        assert_eq!(
            record
                .extra_data
                .as_ref()
                .and_then(|value| value.get("promoted_by")),
            Some(&json!("cached_affinity"))
        );
        assert_eq!(
            record
                .extra_data
                .as_ref()
                .and_then(|value| value.get("demoted_by")),
            Some(&json!("cross_format"))
        );
    }

    #[test]
    fn builds_report_request_candidate_status_record_with_terminal_timestamps() {
        let record =
            build_report_request_candidate_status_record(ReportRequestCandidateStatusRecordInput {
                slot: SchedulerResolvedReportRequestCandidateSlot {
                    id: "cand-1".to_string(),
                    request_id: "req-1".to_string(),
                    user_id: Some("user-1".to_string()),
                    api_key_id: Some("api-key-1".to_string()),
                    candidate_index: 1,
                    retry_index: 0,
                    provider_id: Some("provider-1".to_string()),
                    endpoint_id: Some("endpoint-1".to_string()),
                    key_id: Some("key-1".to_string()),
                    extra_data: None,
                    created_at_unix_ms: 10,
                    started_at_unix_ms: None,
                    finished_at_unix_ms: None,
                },
                status_update: SchedulerRequestCandidateStatusUpdate {
                    status: RequestCandidateStatus::Success,
                    status_code: Some(200),
                    error_type: None,
                    error_message: None,
                    latency_ms: Some(12),
                    started_at_unix_ms: None,
                    finished_at_unix_ms: None,
                },
                now_unix_ms: 123,
            });

        assert_eq!(record.started_at_unix_ms, Some(123));
        assert_eq!(record.finished_at_unix_ms, Some(123));
        assert_eq!(record.created_at_unix_ms, Some(123));
        assert_eq!(record.status, RequestCandidateStatus::Success);
    }

    #[test]
    fn report_request_candidate_status_record_repairs_epoch_created_at() {
        let record =
            build_report_request_candidate_status_record(ReportRequestCandidateStatusRecordInput {
                slot: SchedulerResolvedReportRequestCandidateSlot {
                    id: "cand-epoch".to_string(),
                    request_id: "req-epoch".to_string(),
                    user_id: None,
                    api_key_id: None,
                    candidate_index: 0,
                    retry_index: 0,
                    provider_id: Some("provider-1".to_string()),
                    endpoint_id: Some("endpoint-1".to_string()),
                    key_id: Some("key-1".to_string()),
                    extra_data: None,
                    created_at_unix_ms: 0,
                    started_at_unix_ms: None,
                    finished_at_unix_ms: None,
                },
                status_update: SchedulerRequestCandidateStatusUpdate {
                    status: RequestCandidateStatus::Success,
                    status_code: Some(200),
                    error_type: None,
                    error_message: None,
                    latency_ms: Some(12),
                    started_at_unix_ms: Some(2_000),
                    finished_at_unix_ms: Some(3_000),
                },
                now_unix_ms: 4_000,
            });

        assert_eq!(record.created_at_unix_ms, Some(2_000));
        assert_eq!(record.started_at_unix_ms, Some(2_000));
        assert_eq!(record.finished_at_unix_ms, Some(3_000));
    }
}