#!/bin/bash

# Provides the get_retrofit_dates helper for identifying missing market-data archives on a remote host.
get_retrofit_dates() {
    local host=${1:-}
    local root_dir=${2:-}
    local filename_glob=${3:-}
    local day_count=${4:-}

    if [[ -z "$host" || -z "$root_dir" || -z "$filename_glob" || -z "$day_count" ]]; then
        echo "usage: get_retrofit_dates <host> <root_dir> <filename_glob> <day_count>" >&2
        return 1
    fi

    if ! [[ "$day_count" =~ ^[0-9]+$ ]] || (( day_count <= 0 )); then
        echo "get_retrofit_dates: <day_count> must be a positive integer" >&2
        return 1
    fi

    local -a target_dates=()
    declare -A month_dirs=()

    if ! date -d "1 day ago" +%Y%m%d >/dev/null 2>&1; then
        echo "get_retrofit_dates: requires GNU date arithmetic" >&2
        return 1
    fi

    local offset date
    for (( offset = 1; offset <= day_count; offset++ )); do
        date=$(date -d "$offset day ago" +%Y%m%d)
        target_dates+=("$date")
        month_dirs["${date:0:4}/${date:4:2}"]=1
    done

    declare -A existing_dates=()

    local dir remote_path remote_cmd remote_output entry
    for dir in "${!month_dirs[@]}"; do
        remote_path="$root_dir/$dir"
        printf -v remote_cmd "cd %q 2>/dev/null && LC_ALL=C ls -1" "$remote_path"
        remote_output=$(ssh "$host" "$remote_cmd" 2>/dev/null || true)

        if [[ -n "$remote_output" ]]; then
            while IFS= read -r entry; do
                [[ -z "$entry" ]] && continue
                [[ $entry == $filename_glob ]] || continue
                if [[ "$entry" =~ ^([0-9]{8}) ]]; then
                  existing_dates["${BASH_REMATCH[1]}"]=1
                fi
            done <<<"$remote_output"
        fi
    done

    local -a missing_dates=()
    local idx
    for (( idx = ${#target_dates[@]} - 1; idx >= 0; idx-- )); do
        local dt=${target_dates[$idx]}
        [[ -n "${existing_dates[$dt]:-}" ]] || missing_dates+=("$dt")
    done

    printf '%s\n' "${missing_dates[@]}"
}

is_equity_business_date() {
    local ymd=${1:-}

    if [[ ! "$ymd" =~ ^[0-9]{8}$ ]]; then
        echo "is_equity_business_date: expected YYYYMMDD, got \"$ymd\"" >&2
        return 2
    fi

    local iso_date="${ymd:0:4}-${ymd:4:2}-${ymd:6:2}"
    local url="https://trading-calendar.cvtt.net/api/v1/markets/hours?mic=XNYS&start=${iso_date}&end=${iso_date}"
    local response

    if ! response=$(curl -fsS "$url" 2>/dev/null); then
        echo "is_equity_business_date: failed to query trading calendar API" >&2
        return 1
    fi

    if [[ "$response" =~ \[\s*\] ]]; then
        return 1
    fi

    return 0
}

get_equity_retrofit_dates() {
    local host=${1:-}
    local root_dir=${2:-}
    local filename_glob=${3:-}
    local day_count=${4:-}

    if [[ -z "$host" || -z "$root_dir" || -z "$filename_glob" || -z "$day_count" ]]; then
        echo "usage: get_equity_retrofit_dates <host> <root_dir> <filename_glob> <day_count>" >&2
        return 1
    fi

    if ! [[ "$day_count" =~ ^[0-9]+$ ]] || (( day_count <= 0 )); then
        echo "get_equity_retrofit_dates: <day_count> must be a positive integer" >&2
        return 1
    fi

    if ! date -d "1 day ago" +%Y%m%d >/dev/null 2>&1; then
        echo "get_equity_retrofit_dates: requires GNU date arithmetic" >&2
        return 1
    fi

    local -a target_dates=()
    local offset date weekday
    for (( offset = 1; offset <= day_count; offset++ )); do
        date=$(date -d "$offset day ago" +%Y%m%d)
        weekday=$(date -d "$date" +%u)
        (( weekday >= 6 )) && continue
        target_dates+=("$date")
    done

    declare -A existing_dates=()

    local remote_cmd remote_output entry
    printf -v remote_cmd "cd %q 2>/dev/null && LC_ALL=C ls -1 %s" "$root_dir" "$filename_glob"
    remote_output=$(ssh "$host" "$remote_cmd" 2>/dev/null || true)

    if [[ -n "$remote_output" ]]; then
        while IFS= read -r entry; do
            [[ -z "$entry" ]] && continue
            if [[ "$entry" =~ ^([0-9]{8}) ]]; then
                existing_dates["${BASH_REMATCH[1]}"]=1
            fi
        done <<<"$remote_output"
    fi

    local -a missing_dates=()
    local idx dt tmp rc
    for (( idx = ${#target_dates[@]} - 1; idx >= 0; idx-- )); do
        dt=${target_dates[$idx]}
        [[ -n "${existing_dates[$dt]:-}" ]] && continue
        is_equity_business_date "$dt"
        rc=$?
        if (( rc != 0 )); then
            continue
        fi
        if ! tmp=$(date -d "$dt" +%Y-%m-%d 2>/dev/null); then
            echo "invalid date \"$dt\"" >&2
            return 1
        fi
        missing_dates+=("$tmp")
    done

    printf '%s\n' "${missing_dates[@]}"
}