use std::{
    collections::{HashMap, HashSet},
    fs,
    sync::Arc,
};

use jiff::tz::TimeZone as JiffTimeZone;
use serde::Deserialize;
use serde_json::Value;

use crate::{
    LoadedEntry, PricingMap, Result, TimestampMs, TokenUsageRaw, UsageEntry, UsageMessage,
    calculate_cost_for_usage, cli::CostMode, format_date_tz, format_rfc3339_millis,
    missing_pricing_model_for_candidates, total_usage_tokens,
};
use ccusage_adapter_common::jsonl;
use ccusage_core::fast::LinePrefilter;

use super::paths::GrokSessionFiles;

#[derive(Debug, Default, Deserialize)]
struct GrokUpdateLine {
    #[serde(default)]
    timestamp: Option<Value>,
    #[serde(default)]
    params: Option<GrokParams>,
}

#[derive(Debug, Default, Deserialize)]
struct GrokParams {
    #[serde(
        default,
        rename = "sessionId",
        deserialize_with = "jsonl::non_empty_string"
    )]
    session_id: Option<String>,
    #[serde(default)]
    update: Option<GrokUpdate>,
    #[serde(default, rename = "_meta")]
    meta: Option<GrokMeta>,
}

#[derive(Debug, Default, Deserialize)]
struct GrokUpdate {
    #[serde(
        default,
        rename = "sessionUpdate",
        deserialize_with = "jsonl::non_empty_string"
    )]
    session_update: Option<String>,
    #[serde(default)]
    usage: Option<GrokUsage>,
}

#[derive(Debug, Default, Deserialize)]
struct GrokMeta {
    #[serde(
        default,
        rename = "eventId",
        deserialize_with = "jsonl::non_empty_string"
    )]
    event_id: Option<String>,
    #[serde(default, rename = "agentTimestampMs")]
    agent_timestamp_ms: Option<Value>,
}

#[derive(Debug, Default, Deserialize)]
#[serde(rename_all = "camelCase")]
struct GrokUsage {
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    input_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    output_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    cached_read_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    cache_creation_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    reasoning_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    total_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    cost_usd_ticks: u64,
    #[serde(default)]
    model_usage: Option<HashMap<String, GrokModelUsage>>,
}

#[derive(Debug, Default, Clone, Copy, Deserialize)]
#[serde(rename_all = "camelCase")]
struct GrokModelUsage {
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    input_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    output_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    cached_read_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    cache_creation_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    reasoning_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    total_tokens: u64,
    #[serde(default, deserialize_with = "jsonl::lenient_u64")]
    cost_usd_ticks: u64,
}

#[derive(Debug, Default, Deserialize)]
struct GrokSummary {
    #[serde(default)]
    info: Option<GrokSummaryInfo>,
    #[serde(
        default,
        rename = "git_root_dir",
        deserialize_with = "jsonl::non_empty_string"
    )]
    git_root_dir: Option<String>,
    #[serde(
        default,
        rename = "current_model_id",
        deserialize_with = "jsonl::non_empty_string"
    )]
    current_model_id: Option<String>,
}

#[derive(Debug, Default, Deserialize)]
struct GrokSummaryInfo {
    #[serde(default, deserialize_with = "jsonl::non_empty_string")]
    id: Option<String>,
    #[serde(default, deserialize_with = "jsonl::non_empty_string")]
    cwd: Option<String>,
}

#[derive(Debug, Clone)]
struct SessionMeta {
    session_id: String,
    project_path: String,
    default_model: Option<String>,
}

/// `costUsdTicks` are fixed-point USD: one tick is 1e-10 USD.
///
/// Verified against 58 turns of Grok CLI 1.0.0 data: every turn's
/// `costUsdTicks / 1e10` reproduced the xAI list price for `xai/grok-4.5`
/// exactly. Grok bills each API request separately, but a `turn_completed` row
/// only carries the sum over the requests in that turn. Recomputing from those
/// totals therefore cannot place the long-context tier boundary where Grok did,
/// and lands on either side of the real figure depending on how the turn split;
/// the recorded ticks are the only value that survives the aggregation.
const COST_USD_TICKS_PER_USD: f64 = 1e10;

/// Convert Grok's fixed-point `costUsdTicks` into USD, if the record carried any.
fn cost_usd_from_ticks(ticks: u64) -> Option<f64> {
    (ticks > 0).then(|| ticks as f64 / COST_USD_TICKS_PER_USD)
}

/// Split OpenAI-style input that includes cache: uncached = input − cache.
fn split_tokens(input: u64, cached: u64) -> (u64, u64) {
    let cache = cached.min(input);
    let uncached = input.saturating_sub(cache);
    (uncached, cache)
}

/// Split `inputTokens` into its uncached, cache-read and cache-write parts.
///
/// `cachedReadTokens` is provably a subset of `inputTokens`: session totals match
/// `logs/unified.jsonl`, where `cached_prompt_tokens` is part of `prompt_tokens`.
/// `cacheCreationTokens` arrived later and has only ever been observed as zero, so
/// it is treated as a sibling subset rather than an extra bucket on top; that keeps
/// the three parts summing back to `inputTokens` either way.
fn split_input_tokens(input: u64, cached_read: u64, cache_creation: u64) -> (u64, u64, u64) {
    let (uncached, cache_read) = split_tokens(input, cached_read);
    let cache_creation = cache_creation.min(uncached);
    (uncached - cache_creation, cache_read, cache_creation)
}

/// Pricing lookup candidates for a raw Grok model id (e.g. `grok-4.5-build`).
fn pricing_candidates(raw_model: &str) -> Vec<String> {
    let mut candidates = Vec::new();
    let mut push = |value: String| {
        if !candidates.iter().any(|existing| existing == &value) {
            candidates.push(value);
        }
    };

    let stripped = raw_model
        .strip_prefix("[grok] ")
        .unwrap_or(raw_model)
        .trim();
    if stripped.is_empty() {
        return candidates;
    }

    let normalized = stripped
        .strip_suffix("-build")
        .unwrap_or(stripped)
        .to_string();

    push(stripped.to_string());
    push(format!("xai/{stripped}"));
    push(format!("x-ai/{stripped}"));
    push(normalized.clone());
    push(format!("xai/{normalized}"));
    push(format!("x-ai/{normalized}"));
    candidates
}

pub(super) fn parse_session_files(
    files: &GrokSessionFiles,
    tz: Option<&JiffTimeZone>,
    mode: CostMode,
    pricing: &PricingMap,
) -> Result<Vec<LoadedEntry>> {
    let meta = load_session_meta(files);
    let content = fs::read(&files.updates)?;
    let prefilter = LinePrefilter::all(&[br#""turn_completed""#]);
    let mut entries = Vec::new();
    let mut seen = HashSet::new();

    for line in jsonl::records::<GrokUpdateLine>(&content, Some(&prefilter)) {
        let Some(params) = line.params.as_ref() else {
            continue;
        };
        let Some(update) = params.update.as_ref() else {
            continue;
        };
        if update.session_update.as_deref() != Some("turn_completed") {
            continue;
        }
        let Some(usage) = update.usage.as_ref() else {
            continue;
        };

        let event_id = params.meta.as_ref().and_then(|meta| meta.event_id.clone());
        let timestamp_ms = resolve_timestamp_ms(&line, params.meta.as_ref());
        let session_id = params
            .session_id
            .clone()
            .unwrap_or_else(|| meta.session_id.clone());

        let model_rows = model_usage_rows(usage, meta.default_model.as_deref());
        for (raw_model, model_usage) in model_rows {
            let (uncached, cache, cache_creation) = split_input_tokens(
                model_usage.input_tokens,
                model_usage.cached_read_tokens,
                model_usage.cache_creation_tokens,
            );
            let output_tokens = model_usage.output_tokens;
            let reasoning_tokens = model_usage.reasoning_tokens;
            if uncached == 0
                && cache == 0
                && cache_creation == 0
                && output_tokens == 0
                && reasoning_tokens == 0
            {
                continue;
            }
            let usage_raw = TokenUsageRaw {
                input_tokens: uncached,
                output_tokens,
                cache_creation_input_tokens: cache_creation,
                cache_read_input_tokens: cache,
                speed: None,
                cache_creation: None,
            };

            let dedupe_key = dedupe_key(
                event_id.as_deref(),
                &session_id,
                timestamp_ms,
                &raw_model,
                usage_raw,
                reasoning_tokens,
            );
            if !seen.insert(dedupe_key) {
                continue;
            }

            // Display the raw modelUsage key (e.g. grok-4.5-build); Agent column already
            // identifies the source in unified reports.
            let display_model = raw_model.clone();
            let cost_usd = cost_usd_from_ticks(model_usage.cost_usd_ticks);
            // Cost bills full output_tokens only; reasoning is never added to billable output.
            let cost = calculate_grok_cost(&raw_model, usage_raw, cost_usd, mode, pricing);
            let missing_pricing_model =
                missing_grok_pricing(&raw_model, usage_raw, cost_usd, mode, pricing);
            let timestamp_text = format_rfc3339_millis(timestamp_ms);
            let data = UsageEntry {
                session_id: Some(session_id.clone()),
                timestamp: timestamp_text,
                version: None,
                message: UsageMessage {
                    usage: usage_raw,
                    model: Some(display_model.clone()),
                    id: event_id.clone(),
                },
                cost_usd,
                request_id: event_id.clone(),
                is_api_error_message: None,
                is_sidechain: None,
            };
            entries.push(LoadedEntry {
                data,
                timestamp: timestamp_ms,
                date: format_date_tz(timestamp_ms, tz),
                project: Arc::from("grok"),
                session_id: Arc::from(session_id.clone()),
                project_path: Arc::from(meta.project_path.as_str()),
                cost,
                credits: None,
                model: Some(display_model),
                message_count: None,
                usage_limit_reset_time: None,
                missing_pricing_model,
                // Grok reports `totalTokens == inputTokens + outputTokens`, so its
                // reasoning tokens are already a subset of the output count. Adding
                // them to `extra_total_tokens` would bill them into the grand total a
                // second time.
                extra_total_tokens: 0,
            });
            let _ = model_usage.total_tokens;
        }
    }

    Ok(entries)
}

fn model_usage_rows(
    usage: &GrokUsage,
    default_model: Option<&str>,
) -> Vec<(String, GrokModelUsage)> {
    if let Some(map) = usage.model_usage.as_ref()
        && !map.is_empty()
    {
        let mut rows: Vec<_> = map
            .iter()
            .map(|(model, usage)| (model.clone(), *usage))
            .collect();
        rows.sort_by(|a, b| a.0.cmp(&b.0));
        return rows;
    }

    let model = default_model
        .map(str::to_string)
        .unwrap_or_else(|| "unknown".to_string());
    vec![(
        model,
        GrokModelUsage {
            input_tokens: usage.input_tokens,
            output_tokens: usage.output_tokens,
            cached_read_tokens: usage.cached_read_tokens,
            cache_creation_tokens: usage.cache_creation_tokens,
            reasoning_tokens: usage.reasoning_tokens,
            total_tokens: usage.total_tokens,
            cost_usd_ticks: usage.cost_usd_ticks,
        },
    )]
}

fn load_session_meta(files: &GrokSessionFiles) -> SessionMeta {
    let session_dir_name = files
        .updates
        .parent()
        .and_then(|parent| parent.file_name())
        .and_then(|name| name.to_str())
        .unwrap_or("unknown")
        .to_string();
    let project_from_path = files
        .updates
        .parent()
        .and_then(|session| session.parent())
        .and_then(|project| project.file_name())
        .and_then(|name| name.to_str())
        .map(url_decode_lightweight)
        .unwrap_or_else(|| "unknown".to_string());

    let mut session_id = session_dir_name;
    let mut project_path = project_from_path;
    let mut default_model = None;

    if let Some(summary_path) = files.summary.as_ref()
        && let Ok(content) = fs::read_to_string(summary_path)
        && let Ok(summary) = serde_json::from_str::<GrokSummary>(&content)
    {
        if let Some(id) = summary.info.as_ref().and_then(|info| info.id.clone()) {
            session_id = id;
        }
        if let Some(cwd) = summary
            .info
            .as_ref()
            .and_then(|info| info.cwd.clone())
            .or(summary.git_root_dir)
        {
            project_path = cwd;
        }
        default_model = summary.current_model_id;
    }

    SessionMeta {
        session_id,
        project_path,
        default_model,
    }
}

fn resolve_timestamp_ms(line: &GrokUpdateLine, meta: Option<&GrokMeta>) -> TimestampMs {
    if let Some(ms) = meta
        .and_then(|meta| meta.agent_timestamp_ms.as_ref())
        .and_then(value_as_i64)
        && ms > 0
    {
        return TimestampMs::from_millis(ms);
    }
    if let Some(seconds) = line.timestamp.as_ref().and_then(value_as_i64)
        && seconds > 0
    {
        // Grok writes Unix seconds on the envelope timestamp field.
        return TimestampMs::from_millis(seconds.saturating_mul(1000));
    }
    TimestampMs::UNIX_EPOCH
}

fn value_as_i64(value: &Value) -> Option<i64> {
    value
        .as_i64()
        .or_else(|| value.as_u64().and_then(|n| i64::try_from(n).ok()))
        .or_else(|| value.as_f64().map(|n| n as i64))
}

fn dedupe_key(
    event_id: Option<&str>,
    session_id: &str,
    timestamp: TimestampMs,
    model: &str,
    usage: TokenUsageRaw,
    reasoning: u64,
) -> String {
    if let Some(event_id) = event_id {
        return format!("{event_id}|{model}");
    }
    format!(
        "{session_id}|{}|{model}|{}|{}|{}|{}|{reasoning}",
        timestamp.as_millis(),
        usage.input_tokens,
        usage.output_tokens,
        usage.cache_read_input_tokens,
        usage.cache_creation_input_tokens,
    )
}

fn calculate_grok_cost(
    raw_model: &str,
    usage: TokenUsageRaw,
    cost_usd: Option<f64>,
    mode: CostMode,
    pricing: &PricingMap,
) -> f64 {
    match mode {
        CostMode::Display => cost_usd.unwrap_or(0.0),
        // Grok's own figure is authoritative, so `auto` prefers it and only falls
        // back to the pricing table when a turn recorded no ticks.
        CostMode::Auto if cost_usd.is_some() => cost_usd.unwrap_or(0.0),
        CostMode::Auto | CostMode::Calculate => {
            // Exact hits across every candidate first: `find` falls back to
            // substring matching, and a fuzzy hit on the first candidate would
            // shadow an exact entry - a user pricing override included - that a
            // later candidate names precisely.
            let candidates = pricing_candidates(raw_model);
            for candidate in &candidates {
                if pricing.find_exact(candidate).is_some() {
                    return calculate_cost_for_usage(
                        Some(candidate),
                        usage,
                        None,
                        CostMode::Calculate,
                        Some(pricing),
                    );
                }
            }
            for candidate in &candidates {
                if pricing.find(candidate).is_some() {
                    return calculate_cost_for_usage(
                        Some(candidate),
                        usage,
                        None,
                        CostMode::Calculate,
                        Some(pricing),
                    );
                }
            }
            0.0
        }
    }
}

fn missing_grok_pricing(
    raw_model: &str,
    usage: TokenUsageRaw,
    cost_usd: Option<f64>,
    mode: CostMode,
    pricing: &PricingMap,
) -> Option<String> {
    // A turn that carried its own cost needs no pricing entry, so `display` and a
    // ticks-backed `auto` never warn about a missing model.
    if mode == CostMode::Display || (mode == CostMode::Auto && cost_usd.is_some()) {
        return None;
    }
    missing_pricing_model_for_candidates(
        raw_model,
        pricing_candidates(raw_model),
        total_usage_tokens(usage),
        Some(pricing),
    )
}

fn url_decode_lightweight(value: &str) -> String {
    // Session parents are URL-encoded cwd paths (e.g. `D%3A%5Cproj`).
    let bytes = value.as_bytes();
    // Decode into bytes, not chars: a percent triplet is one UTF-8 byte, so
    // pushing it as a `char` would turn a multi-byte path segment into mojibake.
    let mut out = Vec::with_capacity(value.len());
    let mut i = 0;
    while i < bytes.len() {
        if bytes[i] == b'%'
            && i + 2 < bytes.len()
            && let (Some(hi), Some(lo)) = (from_hex(bytes[i + 1]), from_hex(bytes[i + 2]))
        {
            out.push(hi * 16 + lo);
            i += 3;
            continue;
        }
        out.push(bytes[i]);
        i += 1;
    }
    String::from_utf8_lossy(&out).into_owned()
}

fn from_hex(byte: u8) -> Option<u8> {
    match byte {
        b'0'..=b'9' => Some(byte - b'0'),
        b'a'..=b'f' => Some(byte - b'a' + 10),
        b'A'..=b'F' => Some(byte - b'A' + 10),
        _ => None,
    }
}

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

    fn sample_turn_completed_line() -> String {
        r#"{"timestamp":1750000000,"method":"_x.ai/session/update","params":{"sessionId":"sess-1","update":{"sessionUpdate":"turn_completed","usage":{"inputTokens":100,"outputTokens":20,"cachedReadTokens":40,"reasoningTokens":10,"totalTokens":120,"modelUsage":{"grok-4.5-build":{"inputTokens":100,"outputTokens":20,"cachedReadTokens":40,"reasoningTokens":10,"totalTokens":120}}}},"_meta":{"eventId":"evt-1"}}}"#.to_string()
    }

    #[derive(Clone, Copy)]
    struct TurnTokens {
        input: u64,
        output: u64,
        cache: u64,
        reasoning: u64,
    }

    fn turn_line(
        event_id: &str,
        model: &str,
        tokens: TurnTokens,
        envelope_seconds: i64,
        agent_ms: Option<i64>,
    ) -> String {
        let mut meta = serde_json::json!({ "eventId": event_id });
        if let Some(ms) = agent_ms {
            meta["agentTimestampMs"] = serde_json::json!(ms);
        }
        let TurnTokens {
            input,
            output,
            cache,
            reasoning,
        } = tokens;
        serde_json::json!({
            "timestamp": envelope_seconds,
            "params": {
                "sessionId": "sess-1",
                "update": {
                    "sessionUpdate": "turn_completed",
                    "usage": {
                        "inputTokens": input,
                        "outputTokens": output,
                        "cachedReadTokens": cache,
                        "reasoningTokens": reasoning,
                        "modelUsage": {
                            model: {
                                "inputTokens": input,
                                "outputTokens": output,
                                "cachedReadTokens": cache,
                                "reasoningTokens": reasoning,
                            }
                        }
                    }
                },
                "_meta": meta
            }
        })
        .to_string()
    }

    fn parse_lines(content: &str, summary: Option<&str>) -> Vec<LoadedEntry> {
        let fixture = if let Some(summary) = summary {
            fs_fixture!({
                "sessions/proj/sess-1/updates.jsonl": content,
                "sessions/proj/sess-1/summary.json": summary,
            })
        } else {
            fs_fixture!({
                "sessions/proj/sess-1/updates.jsonl": content,
            })
        };
        let files = GrokSessionFiles {
            updates: fixture.path("sessions/proj/sess-1/updates.jsonl"),
            summary: summary.map(|_| fixture.path("sessions/proj/sess-1/summary.json")),
        };
        // Keep the fixture alive until parse finishes by reading paths first.
        let _root = fixture.root().to_path_buf();
        parse_session_files(
            &files,
            Some(&jiff::tz::TimeZone::UTC),
            CostMode::Display,
            &PricingMap::load_embedded(),
        )
        .unwrap()
    }

    #[test]
    fn splits_uncached_input_from_cache() {
        assert_eq!(split_tokens(100, 40), (60, 40));
        assert_eq!(split_tokens(10, 40), (0, 10));
        assert_eq!(split_tokens(0, 5), (0, 0));
    }

    #[test]
    fn pricing_candidates_strip_build_and_add_xai() {
        assert_eq!(
            pricing_candidates("grok-4.5-build"),
            vec![
                "grok-4.5-build".to_string(),
                "xai/grok-4.5-build".to_string(),
                "x-ai/grok-4.5-build".to_string(),
                "grok-4.5".to_string(),
                "xai/grok-4.5".to_string(),
                "x-ai/grok-4.5".to_string(),
            ]
        );
    }

    #[test]
    fn pricing_candidates_strip_grok_bracket_prefix() {
        assert_eq!(
            pricing_candidates("[grok] grok-4.5-build")[0],
            "grok-4.5-build"
        );
        assert!(pricing_candidates("   ").is_empty());
        assert!(pricing_candidates("[grok] ").is_empty());
    }

    #[test]
    fn exact_raw_model_pricing_override_beats_normalized_fallback() {
        let model = "grok-4.3-build".to_string();
        let pricing_override = crate::cli::PricingOverride {
            input_cost_per_token: Some(1.0),
            output_cost_per_token: Some(2.0),
            ..crate::cli::PricingOverride::default()
        };
        let pricing = PricingMap::load_with_overrides(true, false, [(&model, &pricing_override)]);
        let usage = TokenUsageRaw {
            input_tokens: 1,
            output_tokens: 1,
            ..TokenUsageRaw::default()
        };

        assert_eq!(
            calculate_grok_cost(&model, usage, None, CostMode::Calculate, &pricing),
            3.0
        );
    }

    #[test]
    fn prices_via_the_stripped_candidate_when_the_build_form_is_missing() {
        // The model is one no pricing table carries, so only the override key
        // can answer it. That key carries a suffix of its own, which no
        // `-build` candidate can reach: pricing the model therefore proves the
        // stripped candidates ran, rather than the fuzzy lookup answering
        // `xai/<raw>` with a key the raw form already contains.
        let pricing_override = crate::cli::PricingOverride {
            input_cost_per_token: Some(0.001),
            output_cost_per_token: Some(0.002),
            ..crate::cli::PricingOverride::default()
        };
        let key = "xai/grok-unreleased-9.9-preview".to_string();
        let pricing = PricingMap::load_with_overrides(true, false, [(&key, &pricing_override)]);
        for unpriced in [
            "grok-unreleased-9.9-build",
            "xai/grok-unreleased-9.9-build",
            "x-ai/grok-unreleased-9.9-build",
        ] {
            assert!(pricing.find(unpriced).is_none(), "{unpriced} was priced");
        }
        let usage = TokenUsageRaw {
            input_tokens: 10,
            output_tokens: 5,
            cache_read_input_tokens: 0,
            ..TokenUsageRaw::default()
        };

        assert_eq!(
            calculate_grok_cost(
                "grok-unreleased-9.9-build",
                usage,
                None,
                CostMode::Calculate,
                &pricing
            ),
            0.02
        );
    }

    #[test]
    fn reports_an_unpriced_model_as_missing_pricing_instead_of_dropping_it() {
        let fixture = fs_fixture!({
            "sessions/proj/sess-1/updates.jsonl": turn_line(
                "evt-miss",
                "grok-never-priced-build",
                TurnTokens { input: 93, output: 3, cache: 0, reasoning: 0 },
                1_750_000_000,
                None,
            ),
        });
        let files = GrokSessionFiles {
            updates: fixture.path("sessions/proj/sess-1/updates.jsonl"),
            summary: None,
        };
        let pricing = PricingMap::load_embedded();
        let entries = parse_session_files(&files, None, CostMode::Calculate, &pricing).unwrap();

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].model.as_deref(), Some("grok-never-priced-build"));
        assert_eq!(entries[0].data.message.usage.input_tokens, 93);
        assert_eq!(entries[0].cost, 0.0);
        assert_eq!(
            entries[0].missing_pricing_model.as_deref(),
            Some("grok-never-priced-build")
        );
    }

    #[test]
    fn turn_completed_model_usage_maps_tokens_without_double_count() {
        let fixture = fs_fixture!({
            "sessions/proj/sess-1/updates.jsonl": sample_turn_completed_line(),
            "sessions/proj/sess-1/summary.json": r#"{"info":{"id":"sess-1","cwd":"D:\\work\\proj"},"current_model_id":"grok-4.5"}"#,
        });
        let files = GrokSessionFiles {
            updates: fixture.path("sessions/proj/sess-1/updates.jsonl"),
            summary: Some(fixture.path("sessions/proj/sess-1/summary.json")),
        };
        let pricing = PricingMap::load_embedded();
        let entries = parse_session_files(&files, None, CostMode::Calculate, &pricing).unwrap();

        assert_eq!(entries.len(), 1);
        let entry = &entries[0];
        assert_eq!(entry.model.as_deref(), Some("grok-4.5-build"));
        assert_eq!(entry.data.message.usage.input_tokens, 60);
        assert_eq!(entry.data.message.usage.cache_read_input_tokens, 40);
        assert_eq!(entry.data.message.usage.output_tokens, 20);
        assert_eq!(entry.data.message.usage.cache_creation_input_tokens, 0);
        // Reasoning is already inside outputTokens, so it adds nothing to the total.
        assert_eq!(entry.extra_total_tokens, 0);
        // This fixture records no costUsdTicks, so there is no precomputed cost.
        assert!(entry.data.cost_usd.is_none());
        assert_eq!(entry.session_id.as_ref(), "sess-1");
        assert_eq!(entry.project_path.as_ref(), "D:\\work\\proj");
    }

    #[test]
    fn does_not_add_reasoning_tokens_to_the_total() {
        let tokens = TurnTokens {
            input: 0,
            output: 0,
            cache: 0,
            reasoning: 42,
        };
        let line = turn_line("evt-r", "grok-4.5-build", tokens, 1_750_000_000, None);
        let entries = parse_lines(&line, None);

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].data.message.usage.input_tokens, 0);
        assert_eq!(entries[0].data.message.usage.output_tokens, 0);
        assert_eq!(entries[0].extra_total_tokens, 0);
    }

    #[test]
    fn falls_back_to_top_level_usage_when_model_usage_is_absent() {
        let line = r#"{"timestamp":1750000000,"params":{"sessionId":"sess-top","update":{"sessionUpdate":"turn_completed","usage":{"inputTokens":50,"outputTokens":5,"cachedReadTokens":10,"reasoningTokens":2}},"_meta":{"eventId":"evt-top"}}}"#;
        let summary =
            r#"{"info":{"id":"sess-top","cwd":"/tmp/proj"},"current_model_id":"grok-4.5-build"}"#;
        let entries = parse_lines(line, Some(summary));

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].model.as_deref(), Some("grok-4.5-build"));
        assert_eq!(entries[0].data.message.usage.input_tokens, 40);
        assert_eq!(entries[0].data.message.usage.cache_read_input_tokens, 10);
        assert_eq!(entries[0].data.message.usage.output_tokens, 5);
        assert_eq!(entries[0].extra_total_tokens, 0);
    }

    #[test]
    fn names_top_level_usage_unknown_when_summary_has_no_default_model() {
        let line = r#"{"timestamp":1750000000,"params":{"sessionId":"sess-u","update":{"sessionUpdate":"turn_completed","usage":{"inputTokens":10,"outputTokens":1,"cachedReadTokens":0,"reasoningTokens":0}},"_meta":{"eventId":"evt-u"}}}"#;
        let entries = parse_lines(line, None);

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].model.as_deref(), Some("unknown"));
    }

    #[test]
    fn prefers_agent_timestamp_ms_over_envelope_seconds() {
        let tokens = TurnTokens {
            input: 10,
            output: 1,
            cache: 0,
            reasoning: 0,
        };
        let line = turn_line(
            "evt-ts",
            "grok-4.5-build",
            tokens,
            1_750_000_000,
            Some(1_785_328_986_355),
        );
        let entries = parse_lines(&line, None);

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].timestamp.as_millis(), 1_785_328_986_355);
        assert_eq!(entries[0].date, "2026-07-29");
    }

    #[test]
    fn converts_envelope_unix_seconds_to_millis_when_agent_ms_is_absent() {
        let tokens = TurnTokens {
            input: 10,
            output: 1,
            cache: 0,
            reasoning: 0,
        };
        let line = turn_line("evt-sec", "grok-4.5-build", tokens, 1_750_000_000, None);
        let entries = parse_lines(&line, None);

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].timestamp.as_millis(), 1_750_000_000_000);
        assert_eq!(entries[0].date, "2025-06-15");
    }

    #[test]
    fn uses_unix_epoch_when_no_timestamp_fields_are_present() {
        let line = r#"{"params":{"sessionId":"sess-e","update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"grok-4.5-build":{"inputTokens":1,"outputTokens":1,"cachedReadTokens":0,"reasoningTokens":0}}}},"_meta":{"eventId":"evt-e"}}}"#;
        let entries = parse_lines(line, None);

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].timestamp.as_millis(), 0);
    }

    #[test]
    fn summary_cwd_overrides_path_derived_project_and_fills_session_when_line_omits_it() {
        // No params.sessionId — meta from summary.json should supply the session id.
        let line = r#"{"timestamp":1750000000,"params":{"update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"grok-4.5-build":{"inputTokens":10,"outputTokens":1,"cachedReadTokens":0,"reasoningTokens":0}}}},"_meta":{"eventId":"evt-meta"}}}"#;
        let summary = r#"{"info":{"id":"canonical-session","cwd":"D:\\canonical\\cwd"},"git_root_dir":"should-not-win"}"#;
        let entries = parse_lines(line, Some(summary));

        assert_eq!(entries[0].session_id.as_ref(), "canonical-session");
        assert_eq!(entries[0].project_path.as_ref(), "D:\\canonical\\cwd");
    }

    #[test]
    fn line_session_id_beats_summary_id() {
        let line = sample_turn_completed_line();
        let summary = r#"{"info":{"id":"canonical-session","cwd":"D:\\canonical\\cwd"}}"#;
        let entries = parse_lines(&line, Some(summary));

        assert_eq!(entries[0].session_id.as_ref(), "sess-1");
        assert_eq!(entries[0].project_path.as_ref(), "D:\\canonical\\cwd");
    }

    #[test]
    fn url_decodes_project_segment_when_summary_is_absent() {
        // Omit params.sessionId so the session directory name becomes the id.
        let line = r#"{"timestamp":1750000000,"params":{"update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"grok-4.5-build":{"inputTokens":10,"outputTokens":1,"cachedReadTokens":0,"reasoningTokens":0}}}},"_meta":{"eventId":"evt-url"}}}"#;
        let fixture = fs_fixture!({
            "sessions/D%3A%5Cwork%5Cproj/019fa1b1-0000-7000-8000-000000000001/updates.jsonl": line,
        });
        let files = GrokSessionFiles {
            updates: fixture.path(
                "sessions/D%3A%5Cwork%5Cproj/019fa1b1-0000-7000-8000-000000000001/updates.jsonl",
            ),
            summary: None,
        };
        let entries = parse_session_files(
            &files,
            None,
            CostMode::Display,
            &PricingMap::load_embedded(),
        )
        .unwrap();

        assert_eq!(entries.len(), 1);
        assert_eq!(
            entries[0].session_id.as_ref(),
            "019fa1b1-0000-7000-8000-000000000001"
        );
        assert_eq!(entries[0].project_path.as_ref(), "D:\\work\\proj");
    }

    #[test]
    fn url_decode_recombines_wide_scalars_and_tolerates_invalid_bytes() {
        // Three triplets for one scalar, which is what a CJK path segment looks like.
        assert_eq!(
            url_decode_lightweight("%2Ftmp%2F%E6%97%A5%E6%9C%AC"),
            "/tmp/日本"
        );
        assert_eq!(
            url_decode_lightweight("D%3A%5Cwork%5Cproj"),
            "D:\\work\\proj"
        );
        // A triplet that is not valid UTF-8 degrades to the replacement character
        // rather than panicking or truncating the rest of the path.
        assert_eq!(url_decode_lightweight("%2Ftmp%2F%FFx"), "/tmp/\u{fffd}x");
    }

    #[test]
    fn url_decodes_multi_byte_project_segment() {
        // `%C3%A9` is one UTF-8 code point split across two percent triplets.
        let line = r#"{"timestamp":1750000000,"params":{"update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"grok-4.5-build":{"inputTokens":10,"outputTokens":1,"cachedReadTokens":0,"reasoningTokens":0}}}},"_meta":{"eventId":"evt-utf8"}}}"#;
        let fixture = fs_fixture!({
            "sessions/%2Fhome%2F%C3%A9projet/019fa1b1-0000-7000-8000-000000000002/updates.jsonl": line,
        });
        let files = GrokSessionFiles {
            updates: fixture.path(
                "sessions/%2Fhome%2F%C3%A9projet/019fa1b1-0000-7000-8000-000000000002/updates.jsonl",
            ),
            summary: None,
        };
        let entries = parse_session_files(
            &files,
            None,
            CostMode::Display,
            &PricingMap::load_embedded(),
        )
        .unwrap();

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].project_path.as_ref(), "/home/éprojet");
    }

    #[test]
    fn skips_turn_completed_without_usage_and_zero_rows() {
        let lines = [
            r#"{"timestamp":1750000001,"params":{"update":{"sessionUpdate":"tool_call"}}}"#,
            r#"{"timestamp":1750000002,"params":{"update":{"sessionUpdate":"turn_completed"},"_meta":{"eventId":"no-usage"}}}"#,
            r#"{"timestamp":1750000003,"params":{"update":{"sessionUpdate":"turn_completed","usage":{"inputTokens":0,"outputTokens":0,"cachedReadTokens":0,"reasoningTokens":0,"modelUsage":{"grok-4.5":{"inputTokens":0,"outputTokens":0,"cachedReadTokens":0,"reasoningTokens":0}}}},"_meta":{"eventId":"zero"}}}"#,
            r#"{"this is not json"#,
            &sample_turn_completed_line(),
        ]
        .join("\n");
        let entries = parse_lines(&lines, None);
        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].data.message.usage.input_tokens, 60);
    }

    #[test]
    fn multi_model_turn_emits_one_entry_per_model() {
        let line = r#"{"timestamp":1750000100,"params":{"sessionId":"sess-m","update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"model-a":{"inputTokens":10,"outputTokens":2,"cachedReadTokens":0,"reasoningTokens":1},"model-b":{"inputTokens":20,"outputTokens":4,"cachedReadTokens":5,"reasoningTokens":0}}}},"_meta":{"eventId":"evt-multi"}}}"#;
        let mut entries = parse_lines(line, None);
        entries.sort_by(|a, b| a.model.cmp(&b.model));
        assert_eq!(entries.len(), 2);
        assert_eq!(entries[0].model.as_deref(), Some("model-a"));
        assert_eq!(entries[0].data.message.usage.input_tokens, 10);
        assert_eq!(entries[0].extra_total_tokens, 0);
        assert_eq!(entries[1].model.as_deref(), Some("model-b"));
        assert_eq!(entries[1].data.message.usage.input_tokens, 15);
        assert_eq!(entries[1].data.message.usage.cache_read_input_tokens, 5);
    }

    #[test]
    fn dedupes_same_event_id_and_model() {
        let line = sample_turn_completed_line();
        let content = format!("{line}\n{line}\n");
        let entries = parse_lines(&content, None);
        assert_eq!(entries.len(), 1);
    }

    #[test]
    fn dedupes_identical_rows_without_event_id_by_content_key() {
        let line = r#"{"timestamp":1750000000,"params":{"sessionId":"sess-d","update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"grok-4.5-build":{"inputTokens":100,"outputTokens":20,"cachedReadTokens":40,"reasoningTokens":10}}}}}}"#;
        let content = format!("{line}\n{line}\n");
        let entries = parse_lines(&content, None);
        assert_eq!(entries.len(), 1);
    }

    #[test]
    fn keeps_rows_without_event_id_that_differ_only_in_cache_creation() {
        // Both turns leave 80 uncached input, so cache creation is the only
        // discriminator left; dropping one would undercount 20 tokens.
        let with_creation = r#"{"timestamp":1750000000,"params":{"sessionId":"sess-cc","update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"grok-4.5-build":{"inputTokens":100,"outputTokens":5,"cachedReadTokens":0,"cacheCreationTokens":20,"reasoningTokens":0}}}}}}"#;
        let without_creation = r#"{"timestamp":1750000000,"params":{"sessionId":"sess-cc","update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"grok-4.5-build":{"inputTokens":80,"outputTokens":5,"cachedReadTokens":0,"reasoningTokens":0}}}}}}"#;
        let entries = parse_lines(&format!("{with_creation}\n{without_creation}\n"), None);

        assert_eq!(entries.len(), 2);
        assert_eq!(
            entries[0].data.message.usage.cache_creation_input_tokens,
            20
        );
        assert_eq!(entries[1].data.message.usage.cache_creation_input_tokens, 0);
    }

    #[test]
    fn keeps_distinct_models_that_share_an_event_id() {
        let line = r#"{"timestamp":1750000100,"params":{"sessionId":"sess-m","update":{"sessionUpdate":"turn_completed","usage":{"modelUsage":{"model-a":{"inputTokens":10,"outputTokens":1,"cachedReadTokens":0,"reasoningTokens":0},"model-b":{"inputTokens":20,"outputTokens":2,"cachedReadTokens":0,"reasoningTokens":0}}}},"_meta":{"eventId":"evt-shared"}}}"#;
        let entries = parse_lines(line, None);
        assert_eq!(entries.len(), 2);
    }

    #[test]
    fn display_mode_cost_is_zero_and_does_not_flag_missing_pricing() {
        let fixture = fs_fixture!({
            "sessions/proj/sess-1/updates.jsonl": sample_turn_completed_line(),
        });
        let files = GrokSessionFiles {
            updates: fixture.path("sessions/proj/sess-1/updates.jsonl"),
            summary: None,
        };
        let pricing = PricingMap::load_embedded();
        let entries = parse_session_files(&files, None, CostMode::Display, &pricing).unwrap();
        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].cost, 0.0);
        assert_eq!(entries[0].missing_pricing_model, None);
    }

    #[test]
    fn reads_the_recorded_cost_usd_ticks() {
        // Verbatim from a Grok CLI 1.0.0 turn: 185_192_000 ticks is $0.0185192,
        // which is exactly the xAI list price for these token counts.
        let line = r#"{"timestamp":1750000000,"params":{"sessionId":"sess-1","update":{"sessionUpdate":"turn_completed","usage":{"inputTokens":18444,"outputTokens":130,"cachedReadTokens":11264,"reasoningTokens":73,"costUsdTicks":185192000,"modelUsage":{"grok-4.5-build":{"inputTokens":18444,"outputTokens":130,"cachedReadTokens":11264,"reasoningTokens":73,"costUsdTicks":185192000}}}},"_meta":{"eventId":"evt-cost"}}}"#;
        let entries = parse_lines(line, None);

        assert_eq!(entries.len(), 1);
        assert!(
            entries[0]
                .data
                .cost_usd
                .is_some_and(|cost| (cost - 0.0185192).abs() < 1e-12)
        );
        assert!((entries[0].cost - 0.0185192).abs() < 1e-12);
        assert_eq!(entries[0].missing_pricing_model, None);
    }

    #[test]
    fn splits_cache_creation_out_of_the_uncached_input() {
        assert_eq!(split_input_tokens(100, 40, 25), (35, 40, 25));
        // Nothing to carve out when the field is absent, which is every turn observed so far.
        assert_eq!(split_input_tokens(100, 40, 0), (60, 40, 0));
        // A cache-write larger than the remaining input is clamped rather than wrapping.
        assert_eq!(split_input_tokens(100, 40, 999), (0, 40, 60));
    }

    #[test]
    fn reads_cache_creation_tokens() {
        let line = r#"{"timestamp":1750000000,"params":{"sessionId":"sess-1","update":{"sessionUpdate":"turn_completed","usage":{"inputTokens":100,"outputTokens":20,"cachedReadTokens":40,"cacheCreationTokens":25,"reasoningTokens":10,"modelUsage":{"grok-4.5-build":{"inputTokens":100,"outputTokens":20,"cachedReadTokens":40,"cacheCreationTokens":25,"reasoningTokens":10}}}},"_meta":{"eventId":"evt-cc"}}}"#;
        let entries = parse_lines(line, None);

        assert_eq!(entries.len(), 1);
        assert_eq!(entries[0].data.message.usage.input_tokens, 35);
        assert_eq!(entries[0].data.message.usage.cache_read_input_tokens, 40);
        assert_eq!(
            entries[0].data.message.usage.cache_creation_input_tokens,
            25
        );
        assert_eq!(entries[0].data.message.usage.output_tokens, 20);
    }

    #[test]
    fn auto_prefers_recorded_ticks_while_calculate_recomputes() {
        let key = "grok-4.5".to_string();
        let pricing_override = crate::cli::PricingOverride {
            input_cost_per_token: Some(1.0),
            output_cost_per_token: Some(1.0),
            ..crate::cli::PricingOverride::default()
        };
        let pricing = PricingMap::load_with_overrides(true, false, [(&key, &pricing_override)]);
        let usage = TokenUsageRaw {
            input_tokens: 10,
            output_tokens: 10,
            ..TokenUsageRaw::default()
        };

        assert_eq!(
            calculate_grok_cost(
                "grok-4.5-build",
                usage,
                Some(0.25),
                CostMode::Auto,
                &pricing
            ),
            0.25
        );
        assert_eq!(
            calculate_grok_cost(
                "grok-4.5-build",
                usage,
                Some(0.25),
                CostMode::Calculate,
                &pricing
            ),
            20.0
        );
    }

    #[test]
    fn auto_falls_back_to_the_pricing_table_without_ticks() {
        let key = "grok-4.5".to_string();
        let pricing_override = crate::cli::PricingOverride {
            input_cost_per_token: Some(1.0),
            output_cost_per_token: Some(1.0),
            ..crate::cli::PricingOverride::default()
        };
        let pricing = PricingMap::load_with_overrides(true, false, [(&key, &pricing_override)]);
        let usage = TokenUsageRaw {
            input_tokens: 10,
            output_tokens: 10,
            ..TokenUsageRaw::default()
        };

        assert_eq!(
            calculate_grok_cost("grok-4.5-build", usage, None, CostMode::Auto, &pricing),
            20.0
        );
    }
}