steam-user 0.1.0

//! Trade service for Steam Community.

use std::sync::OnceLock;

use chrono::{FixedOffset, TimeZone};
use regex::Regex;
use scraper::{Html, Selector};
use serde_json::json;
use steamid::SteamID;

use crate::{
    client::SteamUser,
    endpoint::steam_endpoint,
    error::SteamUserError,
    types::{ParsedTradeURL, TradeOffer, TradeOfferAsset, TradeOfferItem, TradeOfferItems, TradeOfferPartner, TradeOfferResult, TradeOfferStatus, TradeOfferSummary, TradeOffersResponse},
};

// Selectors used by `get_trade_offer` are static — hoisted to module-level
// `OnceLock<Selector>` so they compile exactly once instead of per trade
// offer (the page can list dozens at a time).
static SEL_TRADE_URL: OnceLock<Selector> = OnceLock::new();
fn sel_trade_url() -> &'static Selector {
    SEL_TRADE_URL.get_or_init(|| Selector::parse("#trade_offer_access_url").expect("valid CSS selector"))
}

static SEL_SUBPAGE: OnceLock<Selector> = OnceLock::new();
fn sel_subpage() -> &'static Selector {
    SEL_SUBPAGE.get_or_init(|| Selector::parse(".profile_subpage_selector > a").expect("valid CSS selector"))
}

static SEL_ESCROW: OnceLock<Selector> = OnceLock::new();
fn sel_escrow() -> &'static Selector {
    SEL_ESCROW.get_or_init(|| Selector::parse(".trade_offers_escrow_explanation > .title").expect("valid CSS selector"))
}

static SEL_TRADEOFFER: OnceLock<Selector> = OnceLock::new();
fn sel_tradeoffer() -> &'static Selector {
    SEL_TRADEOFFER.get_or_init(|| Selector::parse(".profile_leftcol > .tradeoffer").expect("valid CSS selector"))
}

static SEL_PLAYER_AVATAR: OnceLock<Selector> = OnceLock::new();
fn sel_player_avatar() -> &'static Selector {
    SEL_PLAYER_AVATAR.get_or_init(|| Selector::parse(".playerAvatar").expect("valid CSS selector"))
}

static SEL_IMG: OnceLock<Selector> = OnceLock::new();
fn sel_img() -> &'static Selector {
    SEL_IMG.get_or_init(|| Selector::parse("img").expect("valid CSS selector"))
}

static SEL_A: OnceLock<Selector> = OnceLock::new();
fn sel_a() -> &'static Selector {
    SEL_A.get_or_init(|| Selector::parse("a").expect("valid CSS selector"))
}

static SEL_TRADEOFFER_HEADER: OnceLock<Selector> = OnceLock::new();
fn sel_tradeoffer_header() -> &'static Selector {
    SEL_TRADEOFFER_HEADER.get_or_init(|| Selector::parse(".tradeoffer_header").expect("valid CSS selector"))
}

static SEL_ITEMS_CTN: OnceLock<Selector> = OnceLock::new();
fn sel_items_ctn() -> &'static Selector {
    SEL_ITEMS_CTN.get_or_init(|| Selector::parse(".tradeoffer_items_ctn").expect("valid CSS selector"))
}

static SEL_PRIMARY_ITEMS: OnceLock<Selector> = OnceLock::new();
fn sel_primary_items() -> &'static Selector {
    SEL_PRIMARY_ITEMS.get_or_init(|| Selector::parse(".tradeoffer_items_ctn .tradeoffer_items.primary").expect("valid CSS selector"))
}

static SEL_SECONDARY_ITEMS: OnceLock<Selector> = OnceLock::new();
fn sel_secondary_items() -> &'static Selector {
    SEL_SECONDARY_ITEMS.get_or_init(|| Selector::parse(".tradeoffer_items_ctn .tradeoffer_items.secondary").expect("valid CSS selector"))
}

static SEL_AVATAR_LINK: OnceLock<Selector> = OnceLock::new();
fn sel_avatar_link() -> &'static Selector {
    SEL_AVATAR_LINK.get_or_init(|| Selector::parse("a.tradeoffer_avatar").expect("valid CSS selector"))
}

static SEL_TRADE_ITEM: OnceLock<Selector> = OnceLock::new();
fn sel_trade_item() -> &'static Selector {
    SEL_TRADE_ITEM.get_or_init(|| Selector::parse(".tradeoffer_item_list > .trade_item").expect("valid CSS selector"))
}

static SEL_ITEMS_BANNER: OnceLock<Selector> = OnceLock::new();
fn sel_items_banner() -> &'static Selector {
    SEL_ITEMS_BANNER.get_or_init(|| Selector::parse(".tradeoffer_items_banner").expect("valid CSS selector"))
}

static RE_HTML_TAGS: OnceLock<Regex> = OnceLock::new();
fn re_html_tags() -> &'static Regex {
    RE_HTML_TAGS.get_or_init(|| Regex::new(r"<[^>]+>").expect("valid regex"))
}

impl SteamUser {
    /// Retrieves the authenticated user's unique trade offer URL.
    ///
    /// This URL allows other users to send you trade offers without being on
    /// your friends list. The URL is scraped from the user's trade privacy
    /// settings page.
    #[steam_endpoint(GET, host = Community, path = "/my/tradeoffers/privacy", kind = Read)]
    pub async fn get_trade_url(&self) -> Result<Option<String>, SteamUserError> {
        let response = self.get_path("/my/tradeoffers/privacy").send().await?.text().await?;

        let html = Html::parse_document(&response);

        Ok(html.select(sel_trade_url()).next().and_then(|el| el.value().attr("value").map(|v| v.to_string())))
    }

    /// Retrieves a list of active trade offers (incoming and outgoing) from the
    /// trade offers page.
    ///
    /// Scrapes `https://steamcommunity.com/my/tradeoffers/` to extract offer IDs, status, and item summaries.
    #[steam_endpoint(GET, host = Community, path = "/my/tradeoffers/", kind = Read)]
    pub async fn get_trade_offer(&self) -> Result<TradeOffersResponse, SteamUserError> {
        let response = self.get_with_manual_redirects("https://steamcommunity.com/my/tradeoffers/").await?;

        let html = Html::parse_document(&response);

        let mut incoming_offers = TradeOfferSummary { link: String::new(), count: 0 };
        let mut sent_offers = TradeOfferSummary { link: String::new(), count: 0 };
        let mut trade_hold_count = 0;

        for el in html.select(sel_subpage()) {
            let text = el.text().collect::<String>();
            let link = el.value().attr("href").unwrap_or("").trim_end_matches('/').to_string();
            let mut count = 0;
            if let (Some(start), Some(end)) = (text.find('('), text.find(')')) {
                count = text[start + 1..end].trim().parse().unwrap_or(0);
            }

            if link.ends_with("tradeoffers") {
                incoming_offers = TradeOfferSummary { link, count };
            } else if link.ends_with("tradeoffers/sent") {
                sent_offers = TradeOfferSummary { link, count };
            }
        }

        if let Some(el) = html.select(sel_escrow()).next() {
            let text = el.text().collect::<String>().trim().to_string();
            if text.ends_with("trade on hold") || text.ends_with("trades on hold") {
                trade_hold_count = text.split(' ').next().and_then(|s| s.parse().ok()).unwrap_or(0);
            }
        }

        let mut trade_offers = Vec::new();
        for el in html.select(sel_tradeoffer()) {
            let id_str = el.value().attr("id").unwrap_or("");
            if !id_str.starts_with("tradeofferid_") {
                continue;
            }
            let tradeofferid = id_str["tradeofferid_".len()..].parse().unwrap_or(0);
            if tradeofferid == 0 {
                continue;
            }

            let html_content = el.html();
            let partner_data = if let Some(start) = html_content.find("ReportTradeScam(") {
                let rest = &html_content[start + "ReportTradeScam(".len()..];
                if let Some(end) = rest.find(");") {
                    let part = rest[..end].trim();
                    let parts: Vec<String> = part
                        .split(',')
                        .map(|s| {
                            // Decode HTML entities first, then trim quotes/whitespace
                            let decoded = s.trim().replace("&quot;", "\"").replace("&amp;", "&").replace("&lt;", "<").replace("&gt;", ">").replace("&#39;", "'");
                            decoded.trim_matches(|c: char| c == '\'' || c == '"').trim().to_string()
                        })
                        .collect();
                    if parts.len() >= 2 {
                        // Steam embeds the partner SteamID64 as a decimal
                        // string. Parse to SteamID at this boundary; drop the
                        // offer if it doesn't parse so we never carry a
                        // bogus ID forward.
                        let steam_id = parts[0].parse::<SteamID>().ok();
                        let name = decode_js_unicode_escapes(&parts[1]);
                        Some((steam_id, name))
                    } else {
                        None
                    }
                } else {
                    None
                }
            } else {
                None
            };

            let (partner_steam_id, partner_name) = partner_data.unwrap_or_default();

            let player_avatar = el.select(sel_player_avatar()).next();
            let avatar_url = player_avatar.and_then(|a| a.select(sel_img()).next()).and_then(|i| i.value().attr("src")).unwrap_or("");
            let avatar_hash = if let Some(pos) = avatar_url.rfind('/') {
                let filename = &avatar_url[pos + 1..];
                if let Some(dot_pos) = filename.find('.') {
                    filename[..dot_pos].to_string()
                } else {
                    filename.to_string()
                }
            } else {
                String::new()
            };

            let link = player_avatar.and_then(|a| a.select(sel_a()).next()).and_then(|l| l.value().attr("href")).unwrap_or("").to_string();
            let header = el.select(sel_tradeoffer_header()).next().map(|h| h.text().collect::<String>().trim().to_string()).unwrap_or_default();
            let active = el.select(sel_items_ctn()).next().map(|c| c.value().has_class("active", scraper::CaseSensitivity::AsciiCaseInsensitive)).unwrap_or(false);

            let primary_items_ctn = el.select(sel_primary_items()).next();
            let secondary_items_ctn = el.select(sel_secondary_items()).next();

            let primary_steam_id = primary_items_ctn.and_then(|c| c.select(sel_avatar_link()).next()).and_then(|a| a.value().attr("data-miniprofile")).and_then(|m| m.parse::<u32>().ok()).map(SteamID::from_individual_account_id);

            let secondary_steam_id = secondary_items_ctn.and_then(|c| c.select(sel_avatar_link()).next()).and_then(|a| a.value().attr("data-miniprofile")).and_then(|m| m.parse::<u32>().ok()).map(SteamID::from_individual_account_id);

            let parse_items = |ctn: Option<scraper::ElementRef>| {
                let mut items = Vec::new();
                if let Some(ctn) = ctn {
                    for item_el in ctn.select(sel_trade_item()) {
                        let economy_item = item_el.value().attr("data-economy-item").unwrap_or("").to_string();
                        let img = item_el.select(sel_img()).next().and_then(|i| i.value().attr("src")).unwrap_or("").to_string();
                        // Extract high-res image from srcset (2x variant)
                        let img_hi = item_el
                            .select(sel_img())
                            .next()
                            .and_then(|i| i.value().attr("srcset"))
                            .and_then(|srcset| {
                                srcset.split(',').find_map(|entry| {
                                    let entry = entry.trim();
                                    if entry.ends_with("2x") {
                                        Some(entry.trim_end_matches("2x").trim().to_string())
                                    } else {
                                        None
                                    }
                                })
                            })
                            .unwrap_or_default();
                        let missing = item_el.value().has_class("missing", scraper::CaseSensitivity::AsciiCaseInsensitive);
                        items.push(TradeOfferItem { economy_item, img, img_hi, missing });
                    }
                }
                items
            };

            // Parse banner text and status
            let banner_el = el.select(sel_items_banner()).next();
            let banner_text = banner_el.map(|b| b.text().collect::<String>().trim().to_string()).unwrap_or_default();
            let status = if active {
                TradeOfferStatus::Active
            } else if banner_el.map(|b| b.value().has_class("accepted", scraper::CaseSensitivity::AsciiCaseInsensitive)).unwrap_or(false) {
                TradeOfferStatus::Accepted
            } else if banner_text.contains("Unavailable") || banner_text.contains("unavailable") {
                TradeOfferStatus::Unavailable
            } else if banner_text.contains("Counter") || banner_text.contains("counter") {
                TradeOfferStatus::Countered
            } else {
                TradeOfferStatus::Inactive
            };

            let banner_timestamp = parse_steam_banner_timestamp(&banner_text);

            trade_offers.push(TradeOffer {
                tradeofferid,
                partner: TradeOfferPartner { steamid: partner_steam_id, name: partner_name, avatar_hash, link, header },
                active,
                primary: TradeOfferItems { steamid: primary_steam_id, items: parse_items(primary_items_ctn) },
                secondary: TradeOfferItems { steamid: secondary_steam_id, items: parse_items(secondary_items_ctn) },
                banner_text,
                banner_timestamp,
                status,
            });
        }

        Ok(TradeOffersResponse { incoming_offers, sent_offers, trade_hold_count, trade_offers })
    }

    /// Sends a new trade offer to a partner using their trade URL.
    ///
    /// # Arguments
    ///
    /// * `trade_url` - The full trade offer URL of the partner.
    /// * `my_assets` - A list of [`TradeOfferAsset`] from your inventory to
    ///   give.
    /// * `their_assets` - A list of [`TradeOfferAsset`] from their inventory to
    ///   receive.
    /// * `message` - An optional message to include with the trade offer.
    #[steam_endpoint(POST, host = Community, path = "/tradeoffer/new/send", kind = Write)]
    pub async fn send_trade_offer(&self, trade_url: &str, my_assets: Vec<TradeOfferAsset>, their_assets: Vec<TradeOfferAsset>, message: &str) -> Result<TradeOfferResult, SteamUserError> {
        let parsed = self.parse_trade_url(trade_url).ok_or_else(|| SteamUserError::Other("Invalid trade URL".into()))?;

        let json_tradeoffer = json!({
            "newversion": true,
            "version": 3,
            "me": {
                "assets": my_assets,
                "currency": [],
                "ready": false,
            },
            "them": {
                "assets": their_assets,
                "currency": [],
                "ready": false,
            }
        });

        let mut form = Vec::new();
        form.push(("serverid", "1".to_string()));
        form.push(("partner", parsed.steam_id.steam_id64().to_string()));
        form.push(("tradeoffermessage", message.to_string()));
        form.push(("json_tradeoffer", json_tradeoffer.to_string()));
        form.push(("captcha", "".to_string()));
        form.push(("trade_offer_create_params", json!({ "trade_offer_access_token": parsed.token }).to_string()));

        let response = self.post_path("/tradeoffer/new/send").header(reqwest::header::REFERER, trade_url).form(&form).send().await?.text().await?;

        // Check for strError first — Steam returns this on failure instead of
        // tradeofferid
        let raw: serde_json::Value = serde_json::from_str(&response).map_err(|e| SteamUserError::Other(format!("Failed to parse response: {}", e)))?;
        if let Some(str_error) = raw.get("strError").and_then(|v| v.as_str()) {
            // Strip HTML tags for a clean error message
            let clean = str_error.replace("<br>", "\n").replace("<br/>", "\n");
            let clean = re_html_tags().replace_all(&clean, "").to_string();
            return Err(SteamUserError::Other(clean.trim().to_string()));
        }

        let result: TradeOfferResult = serde_json::from_value(raw).map_err(|e| SteamUserError::Other(format!("Failed to parse response: {}", e)))?;
        Ok(result)
    }

    /// Accepts an incoming trade offer.
    ///
    /// # Arguments
    ///
    /// * `trade_offer_id` - The unique ID of the trade offer to accept.
    /// * `partner_steam_id` - Optional Steam ID of the partner. If not
    ///   provided, it will be scraped from the offer page.
    #[steam_endpoint(POST, host = Community, path = "/tradeoffer/{trade_offer_id}/accept", kind = Write)]
    pub async fn accept_trade_offer(&self, trade_offer_id: u64, partner_steam_id: Option<String>) -> Result<String, SteamUserError> {
        let partner_id = if let Some(id) = partner_steam_id {
            id
        } else {
            let page = self.get_path(format!("/tradeoffer/{}", trade_offer_id)).send().await?.text().await?;
            if let Some(start) = page.find("var g_ulTradePartnerSteamID = '") {
                let rest = &page[start + "var g_ulTradePartnerSteamID = '".len()..];
                if let Some(end) = rest.find("';") {
                    rest[..end].to_string()
                } else {
                    return Err(SteamUserError::MalformedResponse("Failed to extract partner Steam ID".into()));
                }
            } else {
                return Err(SteamUserError::MalformedResponse("Failed to extract partner Steam ID".into()));
            }
        };

        let form = vec![("serverid", "1".to_string()), ("tradeofferid", trade_offer_id.to_string()), ("partner", partner_id), ("captcha", String::new())];

        let referer = format!("https://steamcommunity.com/tradeoffer/{}/", trade_offer_id);
        let response = self.post_path(format!("/tradeoffer/{}/accept", trade_offer_id)).header(reqwest::header::REFERER, &referer).form(&form).send().await?.text().await?;

        let data: serde_json::Value = serde_json::from_str(&response).map_err(|e| SteamUserError::Other(format!("Failed to parse response: {}", e)))?;
        if let Some(trade_id) = data.get("tradeid").and_then(|v| v.as_str()) {
            Ok(trade_id.to_string())
        } else {
            Err(SteamUserError::Other(format!("Unexpected response: {}", response)))
        }
    }

    /// Declines or cancels a Steam trade offer.
    ///
    /// # Arguments
    ///
    /// * `trade_offer_id` - The unique ID of the trade offer to decline.
    #[steam_endpoint(POST, host = Community, path = "/tradeoffer/{trade_offer_id}/decline", kind = Write)]
    pub async fn decline_trade_offer(&self, trade_offer_id: u64) -> Result<(), SteamUserError> {
        let referer = format!("https://steamcommunity.com/tradeoffer/{}/", trade_offer_id);
        let response = self.post_path(format!("/tradeoffer/{}/decline", trade_offer_id)).header(reqwest::header::REFERER, &referer).form(&([] as [(&str, &str); 0])).send().await?.text().await?;

        let data: serde_json::Value = serde_json::from_str(&response).map_err(|e| SteamUserError::Other(format!("Failed to parse response: {}", e)))?;
        let success = data.get("success").and_then(|v| v.as_bool().or_else(|| v.as_i64().map(|i| i == 1))).unwrap_or(false);

        if success || data.get("tradeofferid").is_some() || data.get("tradeoffer_id").is_some() {
            Ok(())
        } else {
            Err(SteamUserError::Other(format!("Failed to decline trade offer: {}", response)))
        }
    }

    /// Parses a Steam trade offer URL and extracts key partner information.
    pub fn parse_trade_url(&self, trade_url: &str) -> Option<ParsedTradeURL> {
        let url = url::Url::parse(trade_url).ok()?;
        let partner = url.query_pairs().find(|(k, _)| k == "partner")?.1.to_string();
        let token = url.query_pairs().find(|(k, _)| k == "token").map(|(_, v)| v.to_string());

        let account_id = partner.parse::<u32>().ok()?;
        let steam_id = SteamID::from_individual_account_id(account_id);

        Some(ParsedTradeURL { account_id: partner, steam_id, token })
    }
}

/// Parse a Steam banner timestamp string like "Trade Accepted 8 Mar, 2026 @
/// 3:46am" and return a UTC Unix timestamp (seconds).
///
/// Steam renders these timestamps server-side using the account's configured
/// timezone, which is typically US Pacific Time (UTC-7 PDT / UTC-8 PST).
/// We assume UTC-7 (PDT) by default.
fn parse_steam_banner_timestamp(banner_text: &str) -> Option<i64> {
    // Look for the `@` separator — format is: "<prefix> <day> <Mon>, <year> @
    // <hour>:<min><am/pm>"
    let at_pos = banner_text.find('@');
    if at_pos.is_none() {
        tracing::debug!("[TradeOffer] No '@' in banner text: {:?}", banner_text);
        return None;
    }
    let at_pos = at_pos?;
    let time_part = banner_text[at_pos + 1..].trim(); // "5:20am" or "11:20pm"
    let date_part = banner_text[..at_pos].trim(); // "Trade Accepted 15 Mar, 2026"

    // Extract the date portion: find the first digit to get "<day> <Mon>, <year>"
    let date_start = date_part.find(|c: char| c.is_ascii_digit())?;
    let date_str = date_part[date_start..].trim(); // "15 Mar, 2026"

    // Parse time: "5:20am" -> (hour, minute)
    // Handle possible trailing text after am/pm (e.g., from extra banner content)
    let time_token = time_part.split_whitespace().next().unwrap_or(time_part);
    let am_pm = if time_token.ends_with("am") {
        "AM"
    } else if time_token.ends_with("pm") {
        "PM"
    } else {
        tracing::debug!("[TradeOffer] Cannot determine AM/PM from time_token: {:?} (full time_part: {:?})", time_token, time_part);
        return None;
    };
    let time_digits = time_token.trim_end_matches(|c: char| c.is_ascii_alphabetic());
    let mut time_split = time_digits.split(':');
    let mut hour: u32 = time_split.next()?.trim().parse().ok()?;
    let minute: u32 = time_split.next()?.trim().parse().ok()?;

    // Convert 12-hour to 24-hour
    if am_pm == "AM" && hour == 12 {
        hour = 0;
    }
    if am_pm == "PM" && hour != 12 {
        hour += 12;
    }

    // Parse date: "15 Mar, 2026"
    let date_str = date_str.replace(',', "");
    let mut parts = date_str.split_whitespace();
    let day: u32 = parts.next()?.parse().ok()?;
    let month_str = parts.next()?;
    let year: i32 = parts.next()?.parse().ok()?;

    let month = match month_str {
        "Jan" => 1,
        "Feb" => 2,
        "Mar" => 3,
        "Apr" => 4,
        "May" => 5,
        "Jun" => 6,
        "Jul" => 7,
        "Aug" => 8,
        "Sep" => 9,
        "Oct" => 10,
        "Nov" => 11,
        "Dec" => 12,
        _ => {
            tracing::debug!("[TradeOffer] Unknown month: {:?}", month_str);
            return None;
        }
    };

    // Steam typically uses US Pacific Time (UTC-7 PDT)
    let steam_offset = FixedOffset::west_opt(7 * 3600)?;
    let naive = chrono::NaiveDate::from_ymd_opt(year, month, day)?.and_hms_opt(hour, minute, 0)?;
    let dt = steam_offset.from_local_datetime(&naive).single()?;
    let ts = dt.timestamp();
    tracing::debug!("[TradeOffer] Parsed banner timestamp: {:?} -> UTC {}", banner_text, ts);
    Some(ts)
}

/// Decode JavaScript unicode escape sequences (e.g., `\u01b0\u01a1ng` →
/// `ương`).
fn decode_js_unicode_escapes(s: &str) -> String {
    let mut result = String::with_capacity(s.len());
    let mut chars = s.chars().peekable();
    while let Some(ch) = chars.next() {
        if ch == '\\' && chars.peek() == Some(&'u') {
            chars.next(); // consume 'u'
            let hex: String = chars.by_ref().take(4).collect();
            if hex.len() == 4 {
                if let Ok(code) = u32::from_str_radix(&hex, 16) {
                    // Handle surrogate pairs (\uD800-\uDFFF)
                    if (0xD800..=0xDBFF).contains(&code) {
                        // High surrogate — look for low surrogate
                        let mut low_chars = chars.clone();
                        if low_chars.next() == Some('\\') && low_chars.next() == Some('u') {
                            let low_hex: String = low_chars.by_ref().take(4).collect();
                            if let Ok(low_code) = u32::from_str_radix(&low_hex, 16) {
                                if (0xDC00..=0xDFFF).contains(&low_code) {
                                    let cp = 0x10000 + ((code - 0xD800) << 10) + (low_code - 0xDC00);
                                    if let Some(c) = char::from_u32(cp) {
                                        result.push(c);
                                        // Advance the real iterator past the low surrogate
                                        for _ in 0..6 {
                                            chars.next();
                                        }
                                        continue;
                                    }
                                }
                            }
                        }
                        // Fallback: emit replacement char if surrogate pair is broken
                        result.push(char::REPLACEMENT_CHARACTER);
                    } else if let Some(c) = char::from_u32(code) {
                        result.push(c);
                    } else {
                        result.push(char::REPLACEMENT_CHARACTER);
                    }
                } else {
                    result.push_str("\\u");
                    result.push_str(&hex);
                }
            } else {
                result.push_str("\\u");
                result.push_str(&hex);
            }
        } else {
            result.push(ch);
        }
    }
    result
}